Degradation of microbial polyesters.

Science.gov (United States)

Tokiwa, Yutaka; Calabia, Buenaventurada P

2004-08-01

Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB.

Fungal communities associated with the biodegradation of polyester polyurethane buried under compost at different temperatures.

Science.gov (United States)

Zafar, Urooj; Houlden, Ashley; Robson, Geoffrey D

2013-12-01

Plastics play an essential role in the modern world due to their low cost and durability. However, accumulation of plastic waste in the environment causes wide-scale pollution with long-lasting effects, making plastic waste management expensive and problematic. Polyurethanes (PUs) are heteropolymers that made up ca. 7% of the total plastic production in Europe in 2011. Polyester PUs in particular have been extensively reported as susceptible to microbial biodegradation in the environment, particularly by fungi. In this study, we investigated the impact of composting on PUs, as composting is a microbially rich process that is increasingly being used for the processing of green waste and food waste as an economically viable alternative to landfill disposal. PU coupons were incubated for 12 weeks in fresh compost at 25°C, 45°C, and 50°C to emulate the thermophilic and maturation stages of the composting process. Incubation at all temperatures caused significant physical deterioration of the polyester PU coupons and was associated with extensive fungal colonization. Terminal restriction fragment length polymorphism (TRFLP) analysis and pyrosequencing of the fungal communities on the PU surface and in the surrounding compost revealed that the population on the surface of PU was different from the surrounding compost community, suggesting enrichment and selection. The most dominant fungi identified from the surfaces of PU coupons by pyrosequencing was Fusarium solani at 25°C, while at both 45°C and 50°C, Candida ethanolica was the dominant species. The results of this preliminary study suggest that the composting process has the potential to biodegrade PU waste if optimized further in the future.

Fungal Communities Associated with the Biodegradation of Polyester Polyurethane Buried under Compost at Different Temperatures

Science.gov (United States)

Zafar, Urooj; Houlden, Ashley

2013-01-01

Plastics play an essential role in the modern world due to their low cost and durability. However, accumulation of plastic waste in the environment causes wide-scale pollution with long-lasting effects, making plastic waste management expensive and problematic. Polyurethanes (PUs) are heteropolymers that made up ca. 7% of the total plastic production in Europe in 2011. Polyester PUs in particular have been extensively reported as susceptible to microbial biodegradation in the environment, particularly by fungi. In this study, we investigated the impact of composting on PUs, as composting is a microbially rich process that is increasingly being used for the processing of green waste and food waste as an economically viable alternative to landfill disposal. PU coupons were incubated for 12 weeks in fresh compost at 25°C, 45°C, and 50°C to emulate the thermophilic and maturation stages of the composting process. Incubation at all temperatures caused significant physical deterioration of the polyester PU coupons and was associated with extensive fungal colonization. Terminal restriction fragment length polymorphism (TRFLP) analysis and pyrosequencing of the fungal communities on the PU surface and in the surrounding compost revealed that the population on the surface of PU was different from the surrounding compost community, suggesting enrichment and selection. The most dominant fungi identified from the surfaces of PU coupons by pyrosequencing was Fusarium solani at 25°C, while at both 45°C and 50°C, Candida ethanolica was the dominant species. The results of this preliminary study suggest that the composting process has the potential to biodegrade PU waste if optimized further in the future. PMID:24056469

A review of plastic waste biodegradation.

Science.gov (United States)

Zheng, Ying; Yanful, Ernest K; Bassi, Amarjeet S

2005-01-01

With more and more plastics being employed in human lives and increasing pressure being placed on capacities available for plastic waste disposal, the need for biodegradable plastics and biodegradation of plastic wastes has assumed increasing importance in the last few years. This review looks at the technological advancement made in the development of more easily biodegradable plastics and the biodegradation of conventional plastics by microorganisms. Additives, such as pro-oxidants and starch, are applied in synthetic materials to modify and make plastics biodegradable. Recent research has shown that thermoplastics derived from polyolefins, traditionally considered resistant to biodegradation in ambient environment, are biodegraded following photo-degradation and chemical degradation. Thermoset plastics, such as aliphatic polyester and polyester polyurethane, are easily attacked by microorganisms directly because of the potential hydrolytic cleavage of ester or urethane bonds in their structures. Some microorganisms have been isolated to utilize polyurethane as a sole source of carbon and nitrogen source. Aliphatic-aromatic copolyesters have active commercial applications because of their good mechanical properties and biodegradability. Reviewing published and ongoing studies on plastic biodegradation, this paper attempts to make conclusions on potentially viable methods to reduce impacts of plastic waste on the environment.

A critical review of algal biomass: A versatile platform of bio-based polyesters from renewable resources.

Science.gov (United States)

Noreen, Aqdas; Zia, Khalid Mahmood; Zuber, Mohammad; Ali, Muhammad; Mujahid, Mohammad

2016-05-01

Algal biomass is an excellent renewable resource for the production of polymers and other products due to their higher growth rate, high photosynthetic efficiency, great potential for carbon dioxide fixation, low percentage of lignin and high amount of carbohydrates. Algae contain unique metabolites which are transformed into monomers suitable for development of novel polyesters. This review article mainly focuses on algal bio-refinery concept for polyester synthesis and on exploitation of algae-based biodegradable polyester blends and composites in tissue engineering and controlled drug delivery system. Algae-derived hybrid polyester scaffolds are extensively used for bone, cartilage, cardiac and nerve tissue regeneration due to their biocompatibility and tunable biodegradability. Microcapsules and microspheres of algae-derived polyesters have been used for controlled and continuous release of several pharmaceutical agents and macromolecules to produce humoral and cellular immunity with efficient intracellular delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

Nano-biocomposites based on synthetic aliphatic polyesters and nanoclay

CSIR Research Space (South Africa)

Ojijo, Vincent O

2014-05-01

Full Text Available This article gives an overview of the recent developments in the preparation, characterisation, properties, crystallisation behaviour, and melt rheology of clay-containing composites of biodegradable synthetic aliphatic polyesters such as poly...

Modulation of the gene expression of annulus fibrosus-derived stem cells using poly(ether carbonate urethane)urea scaffolds of tunable elasticity.

Science.gov (United States)

Zhu, Caihong; Li, Jun; Liu, Chen; Zhou, Pinghui; Yang, Huilin; Li, Bin

2016-01-01

Annulus fibrosus (AF) injuries commonly lead to substantial deterioration of the intervertebral disc (IVD). While tissue engineering has recently evolved into a promising approach for AF regeneration, it remains challenging due to the cellular, biochemical, and mechanical heterogeneity of AF tissue. In this study, we explored the use of AF-derived stem cells (AFSCs) to achieve diversified differentiation of cells for AF tissue engineering. Since the differentiation of stem cells relies significantly on the elasticity of the substrate, we synthesized a series of biodegradable poly(ether carbonate urethane)urea (PECUU) materials whose elasticity approximated that of native AF tissue. When AFSCs were cultured on electrospun PECUU fibrous scaffolds, the gene expression of collagen-I in the cells increased with the elasticity of scaffold material, whereas the expression of collagen-II and aggrecan genes showed an opposite trend. At the protein level, the content of collagen-I gradually increased with substrate elasticity, while collagen-II and GAG contents decreased. In addition, the cell traction forces (CTFs) of AFSCs gradually decreased with scaffold elasticity. Such substrate elasticity-dependent changes of AFSCs were similar to the gradual transition in the genetic, biochemical, and biomechanical characteristics of cells from inner to outer regions of native AF tissue. Together, findings from this study indicate that AFSCs, depending on the substrate elasticity, have strong tendencies to differentiate into various types of AF-like cells, thereby providing a solid foundation for the tissue engineering applications of AFSCs. Repairing the annulus fibrosus (AF) of intervertebral disc (IVD) is critical for the treatment of disc degeneration disease, but remains challenging due to the significant heterogeneity of AF tissue. Previously, we have identified rabbit AF-derived stem cells (AFSCs), which are AF tissue-specific and hold promise for AF regeneration. In this

Development auxiliaries for dyeing polyester with disperse dyes at low temperatures

Science.gov (United States)

Carrion-Fite, F. J.; Radei, S.

2017-10-01

High-molecular weight organic compounds known as carriers are widely used to expedite polyester dyeing at atmospheric pressure at 100 °C. However, carriers are usually poorly biodegradable and can partially plasticize fibres. Also, dyeing at temperatures above 100 °C in the absence of a carrier entails using expensive equipment. In this work, we developed an alternative method for dyeing polyester at temperatures below 100 °C that reduces energy expenses, dispenses with the need to invest in new equipment and avoids the undesirable effects of non-biodegradable carriers. The method uses disperse dyes in a microemulsion containing a low proportion of a non-toxic organic solvent and either of two alternative development auxiliaries (coumarin and o-vanillin) that is prepared with the aid of ultrasound.

(Citric acid–co–polycaprolactone triol) polyester

Science.gov (United States)

Thomas, Lynda V.; Nair, Prabha D.

2011-01-01

Tissue engineering holds enormous challenges for materials science, wherein the ideal scaffold to be used is expected to be biocompatible, biodegradable and possess mechanical and physical properties that are suitable for target application. In this context, we have prepared degradable polyesters in different ratios by a simple polycondensation technique with citric acid and polycaprolactone triol. Differential scanning calorimetry indicated that the materials were amorphous based the absence of a crystalline melting peak and the presence of a glass transition temperature below 37°C. These polyesters were found to be hydrophilic and could be tailor-made into tubes and films. Porosity could also be introduced by addition of porogens. All the materials were non-cytotoxic in an in vitro cytotoxicity assay and may degrade via hydrolysis to non-toxic degradation products. These polyesters have potential implications in the field of soft tissue engineering on account of their similarity of properties. PMID:23507730

Surface modification of polyester biomaterials for tissue engineering

International Nuclear Information System (INIS)

Jiao Yanpeng; Cui Fuzhai

2007-01-01

Surfaces play an important role in a biological system for most biological reactions occurring at surfaces and interfaces. The development of biomaterials for tissue engineering is to create perfect surfaces which can provoke specific cellular responses and direct new tissue regeneration. The improvement in biocompatibility of biomaterials for tissue engineering by directed surface modification is an important contribution to biomaterials development. Among many biomaterials used for tissue engineering, polyesters have been well documented for their excellent biodegradability, biocompatibility and nontoxicity. However, poor hydrophilicity and the lack of natural recognition sites on the surface of polyesters have greatly limited their further application in the tissue engineering field. Therefore, how to introduce functional groups or molecules to polyester surfaces, which ideally adjust cell/tissue biological functions, becomes more and more important. In this review, recent advances in polyester surface modification and their applications are reviewed. The development of new technologies or methods used to modify polyester surfaces for developing their biocompatibility is introduced. The results of polyester surface modifications by surface morphological modification, surface chemical group/charge modification, surface biomacromolecule modification and so on are reported in detail. Modified surface properties of polyesters directly related to in vitro/vivo biological performances are presented as well, such as protein adsorption, cell attachment and growth and tissue response. Lastly, the prospect of polyester surface modification is discussed, especially the current conception of biomimetic and molecular recognition. (topical review)

Microbial degradation of polyurethane, polyester polyurethanes and polyether polyurethanes.

Science.gov (United States)

Nakajima-Kambe, T; Shigeno-Akutsu, Y; Nomura, N; Onuma, F; Nakahara, T

1999-02-01

Polyurethane (PUR) is a polymer derived from the condensation of polyisocyanate and polyol and it is widely used as a base material in various industries. PUR, in particular, polyester PUR, is known to be vulnerable to microbial attack. Recently, environmental pollution by plastic wastes has become a serious issue and polyester PUR had attracted attention because of its biodegradability. There are many reports on the degradation of polyester PUR by microorganisms, especially by fungi. Microbial degradation of polyester PUR is thought to be mainly due to the hydrolysis of ester bonds by esterases. Recently, polyester-PUR-degrading enzymes have been purified and their characteristics reported. Among them, a solid-polyester-PUR-degrading enzyme (PUR esterase) derived from Comamonas acidovorans TB-35 had unique characteristics. This enzyme has a hydrophobic PUR-surface-binding domain and a catalytic domain, and the surface-binding domain was considered as being essential for PUR degradation. This hydrophobic surface-binding domain is also observed in other solid-polyester-degrading enzymes such as poly(hydroxyalkanoate) (PHA) depolymerases. There was no significant homology between the amino acid sequence of PUR esterase and that of PHA depolymerases, except in the hydrophobic surface-binding region. Thus, PUR esterase and PHA depolymerase are probably different in terms of their evolutionary origin and it is possible that PUR esterases come to be classified as a new solid-polyester-degrading enzyme family.

Fishing Performance of an Octopus minor Net Pot Made of Biodegradable Twines

OpenAIRE

Kim, Seonghun; Park, Seongwook; Lee, Kyounghoon

2014-01-01

Gillnets and net pots are made of synthetic fiber as polyester (PE) and polyamide (PA). These are often lost by heavy weather or trawling of the active fishing gears. Lost gears result in the ghost fishing because these are non-degradable in seawater and damage to spawning grounds or habitats. To address these problems, biodegradable nets composed of aliphatic polyester were developed. This study describes four types of biodegradable net pots for capturing Octopus minor in Southern Korea,...

Study on the control of the compositions and properties of a biodegradable polyester elastomer

Energy Technology Data Exchange (ETDEWEB)

Liu Quanyong; Weng Jingyi; Zhang Liqun [Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Tan Tianwei, E-mail: liu_quanyong@126.co, E-mail: zhanglq@mail.buct.edu.c [Key Laboratory of Bioprocess of Beijing, Beijing University of Chemical Technology, Beijing 100029 (China)

2009-04-15

Biodegradable polyester elastomers are widely reported to be applied in varied biomedical fields. In this paper, we attempt to investigate how both the thermal-curing time and molar ratio of the monomers affect the final compositions and properties of the novel poly(glycerol-sebacate-citrate) (PGSC) elastomers. First, PGSC elastomers are obtained after the thermal curing of the moldable mixtures consisting of citric acid and poly(glycerol-sebacate) (PGS) prepolymers synthesized in the lab. Then further studies show that, on the one hand, the control of longer thermal-curing time results in elastomers with less sol, lower swelling degree, slower degradation, greater mechanical strength and higher glass transition temperature and, on the other hand, the crosslink with more citric acid is advantageous to greatly improving their mechanical strength and glass transition temperatures, simultaneously decreasing their sol contents, swelling degrees and degradation rates. The PGSC elastomers show thermosetting properties, certain strength, mass losses lower than 20% after 4-week degradation and durative water absorption during degradation. Thus they might be potentially used as degradable bio-coatings, varied soft biomedical membranes and drug delivery matrices.

Contribution of soil esterase to biodegradation of aliphatic polyester agricultural mulch film in cultivated soils.

Science.gov (United States)

Yamamoto-Tamura, Kimiko; Hiradate, Syuntaro; Watanabe, Takashi; Koitabashi, Motoo; Sameshima-Yamashita, Yuka; Yarimizu, Tohru; Kitamoto, Hiroko

2015-01-01

The relationship between degradation speed of soil-buried biodegradable polyester film in a farmland and the characteristics of the predominant polyester-degrading soil microorganisms and enzymes were investigated to determine the BP-degrading ability of cultivated soils through characterization of the basal microbial activities and their transition in soils during BP film degradation. Degradation of poly(butylene succinate-co-adipate) (PBSA) film was evaluated in soil samples from different cultivated fields in Japan for 4 weeks. Both the degradation speed of the PBSA film and the esterase activity were found to be correlated with the ratio of colonies that produced clear zone on fungal minimum medium-agarose plate with emulsified PBSA to the total number colonies counted. Time-dependent change in viable counts of the PBSA-degrading fungi and esterase activities were monitored in soils where buried films showed the most and the least degree of degradation. During the degradation of PBSA film, the viable counts of the PBSA-degrading fungi and the esterase activities in soils, which adhered to the PBSA film, increased with time. The soil, where the film was degraded the fastest, recorded large PBSA-degrading fungal population and showed high esterase activity compared with the other soil samples throughout the incubation period. Meanwhile, esterase activity and viable counts of PBSA-degrading fungi were found to be stable in soils without PBSA film. These results suggest that the higher the distribution ratio of native PBSA-degrading fungi in the soil, the faster the film degradation is. This could be due to the rapid accumulation of secreted esterases in these soils.

Synthetic biodegradable functional polymers for tissue engineering: a brief review

OpenAIRE

BaoLin, GUO; MA, Peter X.

2014-01-01

Scaffolds play a crucial role in tissue engineering. Biodegradable polymers with great processing flexibility are the predominant scaffolding materials. Synthetic biodegradable polymers with well-defined structure and without immunological concerns associated with naturally derived polymers are widely used in tissue engineering. The synthetic biodegradable polymers that are widely used in tissue engineering, including polyesters, polyanhydrides, polyphosphazenes, polyurethane, and poly (glyce...

Study of nanocomposites prepared from polyamides and biodegradable polyesters and poly(ester amide)s

OpenAIRE

Morales Gámez, Laura Teresa

2012-01-01

Premi extraordinari doctorat curs 2011-2012, àmbit d’Enginyeria Industrial Polymer clay nanocomposites of polyamides and biodegradable polymers with three kinds of organomodified clays were prepared by different techniques (in situ polymerization, solution casting, and melt mixing). The polymers used in this research were nylons 56, 65 and 47 and the biodegradable polymers: poly (glycolic acid-alt-6-hydrohexanoic acid) and poly(glycolic acid-alt-6-aminohexanoic acid). The developmen...

Biocompatibility of Poly(ester amide (PEA Microfibrils in Ocular Tissues

Directory of Open Access Journals (Sweden)

Martina Kropp

2014-01-01

Full Text Available Drug delivery systems (DDS are able to deliver, over long periods of time, therapeutic concentrations of drugs requiring frequent administration. Two classes of DDS are available, biodegradable and non-biodegradable. The larger non-biodegradable implants ensure long-term delivery, but require surgical interventions. Biodegradable biomaterials are smaller, injectable implants, but degrade hydrolytically and release drugs in non-zero order kinetics, which is inefficient for long-term sustained drug release. Biodegradable poly(ester amides (PEAs may overcome these difficulties. To assess their ocular biocompatibility and long-term behavior, PEA fibrils were analyzed in vitro and in vivo. In vitro, incubation in vitreous humor changes to PEA structure, suggests degradation by surface erosion, enabling drug release with zero order kinetics. Clinical and histological analysis of PEA fibrils implanted subconjunctivally and intravitreally showed the absence of an inflammatory response or other pathological tissue alteration. This study shows that PEA fibrils are biocompatible with ocular environment and degrade by surface erosion.

Biodegradable compounds: Rheological, mechanical and thermal properties

Science.gov (United States)

Nobile, Maria Rossella; Lucia, G.; Santella, M.; Malinconico, M.; Cerruti, P.; Pantani, R.

2015-12-01

Recently great attention from industry has been focused on biodegradable polyesters derived from renewable resources. In particular, PLA has attracted great interest due to its high strength and high modulus and a good biocompatibility, however its brittleness and low heat distortion temperature (HDT) restrict its wide application. On the other hand, Poly(butylene succinate) (PBS) is a biodegradable polymer with a low tensile modulus but characterized by a high flexibility, excellent impact strength, good thermal and chemical resistance. In this work the two aliphatic biodegradable polyesters PBS and PLA were selected with the aim to obtain a biodegradable material for the industry of plastic cups and plates. PBS was also blended with a thermoplastic starch. Talc was also added to the compounds because of its low cost and its effectiveness in increasing the modulus and the HDT of polymers. The compounds were obtained by melt compounding in a single screw extruder and the rheological, mechanical and thermal properties were investigated. The properties of the two compounds were compared and it was found that the values of the tensile modulus and elongation at break measured for the PBS/PLA/Talc compound make it interesting for the production of disposable plates and cups. In terms of thermal resistance the compounds have HDTs high enough to contain hot food or beverages. The PLA/PBS/Talc compound can be, then, considered as biodegradable substitute for polystyrene for the production of disposable plates and cups for hot food and beverages.

Biodegradative Activities of Selected Environmental Fungi on a Polyester Polyurethane Varnish and Polyether Polyurethane Foams.

Science.gov (United States)

Álvarez-Barragán, Joyce; Domínguez-Malfavón, Lilianha; Vargas-Suárez, Martín; González-Hernández, Ricardo; Aguilar-Osorio, Guillermo; Loza-Tavera, Herminia

2016-09-01

Polyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it is slowly degraded, there are limited recycling processes, and its destruction may generate toxic compounds. In this work, we isolated fungal strains able to grow in mineral medium with a polyester PU (PS-PU; Impranil DLN) or a polyether PU (PE-PU; Poly Lack) varnish as the only carbon source. Of the eight best Impranil-degrading strains, the six best degraders belonged to the Cladosporium cladosporioides complex, including the species C. pseudocladosporioides, C. tenuissimum, C. asperulatum, and C. montecillanum, and the two others were identified as Aspergillus fumigatus and Penicillium chrysogenum The best Impranil degrader, C. pseudocladosporioides strain T1.PL.1, degraded up to 87% after 14 days of incubation. Fourier transform infrared (FTIR) spectroscopy analysis of Impranil degradation by this strain showed a loss of carbonyl groups (1,729 cm(-1)) and N-H bonds (1,540 and 1,261 cm(-1)), and gas chromatography-mass spectrometry (GC-MS) analysis showed a decrease in ester compounds and increase in alcohols and hexane diisocyanate, indicating the hydrolysis of ester and urethane bonds. Extracellular esterase and low urease, but not protease activities were detected at 7 and 14 days of culture in Impranil. The best eight Impranil-degrading fungi were also able to degrade solid foams of the highly recalcitrant PE-PU type to different extents, with the highest levels generating up to 65% of dry-weight losses not previously reported. Scanning electron microscopy (SEM) analysis of fungus-treated foams showed melted and thinner cell wall structures than the non-fungus-treated ones, demonstrating fungal biodegradative action on PE-PU. Polyurethane waste disposal has become a serious problem. In this work, fungal strains able to efficiently degrade different types of polyurethanes are reported, and

Synthetic scaffolds based on biodegradable, functionalized polyesters for tissue engineering applications

NARCIS (Netherlands)

Seyednejad, S.H.

2012-01-01

The aim of this thesis was to investigate the possibility of using a novel hydroxyl-functionalized polyester [poly(hydroxymethylglycolide-co-ε-caprolactone), pHMGCL] (Fig.9) to fabricate scaffolds for tissue engineering applications. Degradable polymers that are frequently used for tissue

Biodegradable products by lipase biocatalysis.

Science.gov (United States)

Linko, Y Y; Lämsä, M; Wu, X; Uosukainen, E; Seppälä, J; Linko, P

1998-11-18

The interest in the applications of biocatalysis in organic syntheses has rapidly increased. In this context, lipases have recently become one of the most studied groups of enzymes. We have demonstrated that lipases can be used as biocatalyst in the production of useful biodegradable compounds. A number of examples are given. 1-Butyl oleate was produced by direct esterification of butanol and oleic acid to decrease the viscosity of biodiesel in winter use. Enzymic alcoholysis of vegetable oils without additional organic solvent has been little investigated. We have shown that a mixture of 2-ethyl-1-hexyl esters can be obtained in a good yield by enzymic transesterification from rapeseed oil fatty acids for use as a solvent. Trimethylolpropane esters were also similarly synthesized as lubricants. Finally, the discovery that lipases can also catalyze ester syntheses and transesterification reactions in organic solvent systems has opened up the possibility of enzyme catalyzed production of biodegradable polyesters. In direct polyesterification of 1,4-butanediol and sebacic acid, polyesters with a mass average molar mass of the order of 56,000 g mol-1 or higher, and a maximum molar mass of about 130,000 g mol-1 were also obtained by using lipase as biocatalyst. Finally, we have demonstrated that also aromatic polyesters can be synthesized by lipase biocatalysis, a higher than 50,000 g mol-1 mass average molar mass of poly(1,6-hexanediyl isophthalate) as an example.

Recent developments and future prospects on bio-based polyesters derived from renewable resources: A review.

Science.gov (United States)

Zia, Khalid Mahmood; Noreen, Aqdas; Zuber, Mohammad; Tabasum, Shazia; Mujahid, Mohammad

2016-01-01

A significantly growing interest is to design a new strategy for development of bio-polyesters from renewable resources due to limited fossil fuel reserves, rise of petrochemicals price and emission of green house gasses. Therefore, this review aims to present an overview on synthesis of biocompatible, biodegradable and cost effective polyesters from biomass and their prospective in different fields including packaging, coating, tissue engineering, drug delivery system and many more. Isosorbide, 2,4:3,5-di-O-methylene-d-mannitol, bicyclic diacetalyzed galactaric acid, 2,5-furandicarboxylic acid, citric, 2,3-O-methylene l-threitol, dimethyl 2,3-O-methylene l-threarate, betulin, dihydrocarvone, decalactone, pimaric acid, ricinoleic acid and sebacic acid, are some important monomers derived from biomass which are used for bio-based polyester manufacturing, consequently, replacing the petrochemical based polyesters. The last part of this review highlights some recent advances in polyester blends and composites in order to improve their properties for exceptional biomedical applications i.e. skin tissue engineering, guided bone regeneration, bone healing process, wound healing and wound acceleration. Copyright © 2015 Elsevier B.V. All rights reserved.

A biodegradable rubber by crosslinking poly(hydroxyalkanoate) from Pseudomonas oleovorans

NARCIS (Netherlands)

DEKONING, GJM; VANBILSEN, HMM; LEMSTRA, PJ; HAZENBERG, W; Witholt, B.; Preusting, H.; VANDERGALIEN, JG; SCHIRMER, A; JENDROSSEK, D

1994-01-01

Poly((R)-3-hydroxyalkanoate)s (PHAs) are bacterial storage polyesters, currently receiving much attention because of their potential application as biodegradable and biocompatible plastics. Among them are the PHAs from Pseudomonas oleovorans, which are semicrystalline elastomers. Their applicability

Design and Applications of Biodegradable Polyester Tissue Scaffolds Based on Endogenous Monomers Found in Human Metabolism

Directory of Open Access Journals (Sweden)

Devin G. Barrett

2009-10-01

Full Text Available Synthetic polyesters have deeply impacted various biomedical and engineering fields, such as tissue scaffolding and therapeutic delivery. Currently, many applications involving polyesters are being explored with polymers derived from monomers that are endogenous to the human metabolism. Examples of these monomers include glycerol, xylitol, sorbitol, and lactic, sebacic, citric, succinic, α-ketoglutaric, and fumaric acids. In terms of mechanical versatility, crystallinity, hydrophobicity, and biocompatibility, polyesters synthesized partially or completely from these monomers can display a wide range of properties. The flexibility in these macromolecular properties allows for materials to be tailored according to the needs of a particular application. Along with the presence of natural monomers that allows for a high probability of biocompatibility, there is also an added benefit that this class of polyesters is more environmentally friendly than many other materials used in biomedical engineering. While the selection of monomers may be limited by nature, these polymers have produced or have the potential to produce an enormous number of successes in vitro and in vivo.

The catalytic microwave synthesis of biodegradable polyester polyols based on castor oil and l-lactide

Science.gov (United States)

Kojić, D.; Erceg, T.; Vukić, N.; Teofilović, V.; Ristić, I.; Budinski-Simendić, J.; Aleksić, V.

2017-01-01

Various strategies for achieving a functional poly(lactic acid) (PLA) have been developed such as ring-opening copolymerization with a functional monomer, the use of functional initiator and various post polymerization modifications. It is possible to obtain the star shaped polymer using natural oil with at least three OH groups as an initiator. It was estimated that despite of low-molecular mass of star-shaped PLA, the hydrophobic castor oil central core influenced the slow degradation rate in the case of injectable biomedical application. The star-shaped polymers with low-molecular-mass have a lower melt viscosity correlated with linear counterparts. In soft tissue reparation the polymer viscosity increases with fluid body contact and the solid implant can be formed. To ensure liquid state at injection temperature the low molar mass polymer is favorable. There is a particular size for each macromolecular chains at which chain entanglement occurs. In this work the influence of the l-lactide (LA) and the castor oil (CO) contents on the size of biodegradable branched polyester polyols was studied. The average molecular masses of synthesized polymers were estimated by GPC procedure. In sample formulations the [LA]/[CO] ratios were from to 113 to 533. Mn values for obtained polymers were from 5000 to 20000 Da. The molecular mass distribution for the resulting polymers was between 1.09 and 1.37.

Synthesis and characterization of poly(ester amide from remewable resources through melt polycondensation

Directory of Open Access Journals (Sweden)

B. B. Wang

2014-01-01

Full Text Available Biodegradable poly(ester amides (PEAs were synthesized from lactic acid and 11-aminoundecanoic acid via melt polycondensation. Molecular weights, chemical structures and thermal properties of the poly(ester amides were characterized in terms of gel permeation chromatography (GPC, Fourier transform infrared spectroscopy (FTIR, 1H nuclear magnetic resonance (1H NMR, differential scanning calorimetry (DSC and thermogravimetric analysis (TGA, respectively. The PEAs have low molecular weights and display a lower cold crystallization temperature as well as smaller crystallinity by comparison with the pure poly(lactic acid (PLA. The incorporation of the 11-aminoundecanoic acid into the PLA chain not only improved the thermal stability but changed the decomposition process.

Microbial Degradation Behavior in Seawater of Polyester Blends Containing Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBHHx

Directory of Open Access Journals (Sweden)

Hitoshi Sashiwa

2018-01-01

Full Text Available The microbial degradation behavior of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate (PHBHHx and its compound with several polyesters such as poly(butylene adipate-co-telephtharate (PBAT, poly(butylene succinate (PBS, and polylactic acid (PLA in seawater was tested by a biological oxygen demand (BOD method. PHBHHx showed excellent biodegradation in seawater in this study. In addition, the biodegradation rate of several blends was much influenced by the weight ratio of PHBHHx in their blends and decreased in accordance with the decrement of PHBHHX ratio. The surface morphology of the sheet was important factor for controlling the biodegradation rate of PHBHHx-containing blends in seawater.

Biodegradation of Polyester Polyurethane by Endophytic Fungi▿

Science.gov (United States)

Russell, Jonathan R.; Huang, Jeffrey; Anand, Pria; Kucera, Kaury; Sandoval, Amanda G.; Dantzler, Kathleen W.; Hickman, DaShawn; Jee, Justin; Kimovec, Farrah M.; Koppstein, David; Marks, Daniel H.; Mittermiller, Paul A.; Núñez, Salvador Joel; Santiago, Marina; Townes, Maria A.; Vishnevetsky, Michael; Williams, Neely E.; Vargas, Mario Percy Núñez; Boulanger, Lori-Ann; Bascom-Slack, Carol; Strobel, Scott A.

2011-01-01

Bioremediation is an important approach to waste reduction that relies on biological processes to break down a variety of pollutants. This is made possible by the vast metabolic diversity of the microbial world. To explore this diversity for the breakdown of plastic, we screened several dozen endophytic fungi for their ability to degrade the synthetic polymer polyester polyurethane (PUR). Several organisms demonstrated the ability to efficiently degrade PUR in both solid and liquid suspensions. Particularly robust activity was observed among several isolates in the genus Pestalotiopsis, although it was not a universal feature of this genus. Two Pestalotiopsis microspora isolates were uniquely able to grow on PUR as the sole carbon source under both aerobic and anaerobic conditions. Molecular characterization of this activity suggests that a serine hydrolase is responsible for degradation of PUR. The broad distribution of activity observed and the unprecedented case of anaerobic growth using PUR as the sole carbon source suggest that endophytes are a promising source of biodiversity from which to screen for metabolic properties useful for bioremediation. PMID:21764951

Biodegradable Shape Memory Polymers in Medicine.

Science.gov (United States)

Peterson, Gregory I; Dobrynin, Andrey V; Becker, Matthew L

2017-11-01

Shape memory materials have emerged as an important class of materials in medicine due to their ability to change shape in response to a specific stimulus, enabling the simplification of medical procedures, use of minimally invasive techniques, and access to new treatment modalities. Shape memory polymers, in particular, are well suited for such applications given their excellent shape memory performance, tunable materials properties, minimal toxicity, and potential for biodegradation and resorption. This review provides an overview of biodegradable shape memory polymers that have been used in medical applications. The majority of biodegradable shape memory polymers are based on thermally responsive polyesters or polymers that contain hydrolyzable ester linkages. These materials have been targeted for use in applications pertaining to embolization, drug delivery, stents, tissue engineering, and wound closure. The development of biodegradable shape memory polymers with unique properties or responsiveness to novel stimuli has the potential to facilitate the optimization and development of new medical applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Progress on biodegradation of polylactic acid--a review].

Science.gov (United States)

Li, Fan; Wang, Sha; Liu, Weifeng; Chen, Guanjun

2008-02-01

Polylactic acid is a high molecular-weight polyester made from renewable resources such as corn or starch. It is a promising biodegradable plastic due to its mechanical properties, biocompatibility and biodegradability. To achieve natural recycling of polylactic acid, relative microorganisms and the underlying mechanisms in the biodegradation has become an important issue in biodegradable materials. Up to date, most isolated microbes capable of degrading polylactic acid belong to actinomycetes. Proteases secreted by these microorganisms are responsible for the degradation. However, subtle differences exist between these polylactic acid degrading enzymes and typical proteases with respect to substrate binding and catalysis. Amino acids relative to catalysis are postulated to be highly plastic allowing their catalytic hydrolysis of polylactic acid. In this paper we reviewed current studies on biodegradation of polylactic acid concerning its microbial, enzymatic reactions and the possible mechanisms. We also discussed the probability of biologically recycling PLA by applying highly efficient strains and enzymes.

Dipeptide-based polyphosphazene and polyester blends for bone tissue engineering.

Science.gov (United States)

Deng, Meng; Nair, Lakshmi S; Nukavarapu, Syam P; Jiang, Tao; Kanner, William A; Li, Xudong; Kumbar, Sangamesh G; Weikel, Arlin L; Krogman, Nicholas R; Allcock, Harry R; Laurencin, Cato T

2010-06-01

Polyphosphazene-polyester blends are attractive materials for bone tissue engineering applications due to their controllable degradation pattern with non-toxic and neutral pH degradation products. In our ongoing quest for an ideal completely miscible polyphosphazene-polyester blend system, we report synthesis and characterization of a mixed-substituent biodegradable polyphosphazene poly[(glycine ethyl glycinato)(1)(phenyl phenoxy)(1)phosphazene] (PNGEG/PhPh) and its blends with a polyester. Two dipeptide-based blends namely 25:75 (Matrix1) and 50:50 (Matrix2) were produced at two different weight ratios of PNGEG/PhPh to poly(lactic acid-glycolic acid) (PLAGA). Blend miscibility was confirmed by differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy. Both blends resulted in higher tensile modulus and strength than the polyester. The blends showed a degradation rate in the order of Matrix2PLAGA in phosphate buffered saline at 37 degrees C over 12 weeks. Significantly higher pH values of degradation media were observed for blends compared to PLAGA confirming the neutralization of PLAGA acidic degradation by polyphosphazene hydrolysis products. The blend components PLAGA and polyphosphazene exhibited a similar degradation pattern as characterized by the molecular weight loss. Furthermore, blends demonstrated significantly higher osteoblast growth rates compared to PLAGA while maintaining osteoblast phenotype over a 21-day culture. Both blends demonstrated improved biocompatibility in a rat subcutaneous implantation model compared to PLAGA over 12 weeks. (c) 2010 Elsevier Ltd. All rights reserved.

Experimental Investigation on Mechanical Properties of Hemp/E-Glass Fabric Reinforced Polyester Hybrid Composites

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M R SANJAY

2016-09-01

Full Text Available This research work has been focusing on Hemp fibers has an alternative reinforcement for fiber reinforced polymer composites due to its eco-friendly and biodegradable characteristics. This work has been carried out to evaluate the mechanical properties of hemp/E-glass fabrics reinforced polyester hybrid composites. Vacuum bagging method was used for the preparation of six different kinds of hemp/glass fabrics reinforced polyester composite laminates as per layering sequences. The tensile, flexural, impact and water absorption tests of these hybrid composites were carried out experimentally according to ASTM standards. It reveals that an addition of E-glass fabrics with hemp fabrics can increase the mechanical properties of composites and decrease the water absorption of the hybrid composites.

Modelling pH-Optimized Degradation of Microgel-Functionalized Polyesters

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Lisa Bürgermeister

2016-01-01

Full Text Available We establish a novel mathematical model to describe and analyze pH levels in the vicinity of poly(N-vinylcaprolactam-co-acetoacetoxyethyl methacrylate-co-N-vinylimidazole (VCL/AAEM/VIm microgel-functionalized polymers during biodegradation. Biodegradable polymers, especially aliphatic polyesters (polylactide/polyglycolide/polycaprolactone homo- and copolymers, have a large range of medical applications including delivery systems, scaffolds, or stents for the treatment of cardiovascular diseases. Most of those applications are limited by the inherent drop of pH level during the degradation process. The combination of polymers with VCL/AAEM/VIm-microgels, which aims at stabilizing pH levels, is innovative and requires new mathematical models for the prediction of pH level evaluation. The mathematical model consists of a diffusion-reaction PDE system for the degradation including reaction rate equations and diffusion of acidic degradation products into the vicinity. A system of algebraic equations is coupled to the degradation model in order to describe the buffering action of the microgel. The model is validated against the experimental pH-monitored biodegradation of microgel-functionalized polymer foils and is available for the design of microgel-functionalized polymer components.

Study of the properties of poly(ester urethanes) following ionizing irradiation

International Nuclear Information System (INIS)

Kornacka, A.M.; Przybytniak, G.

2006-01-01

Copolymers of polyurethanes and polyesters were found unsuitable for long-term implants because of fast hydrolysis of the ester soft segments. On the other hand, such properties make them valuable as gradually degradable biomaterial that might be used as scaffolds for tissue engineering. The elastomeric polyurethanes are known to be radiation stable materials in sterilizing dose. Nevertheless, if additional components appear in the system, e.g. segments of polyesters, then the influence of irradiation is poorly recognized. In presented paper it has been shown that ionizing radiation induces solid state reorganization of the segmented domains, leading to migration of soft segments towards the surface and to grow of hydrophobic properties. Obtained results confirmed that the urethane segments were more resistant towards ionizing irradiation and the presence of ester units facilitated generation of free radicals. It was also found that in poly(ε-caprolactane)diol (PCL) segments ionizing radiation induces radicals that are able to introduce cross-linking in macromolecules, and consequently reduce ability to biodegradation

3D printing of new biobased unsaturated polyesters by microstereo-thermal-lithography

International Nuclear Information System (INIS)

Gonçalves, Filipa A M M; Costa, Cátia S M F; Fabela, Inês G P; Simões, Pedro N; Serra, Arménio C; Coelho, Jorge F J; Farinha, Dina; Faneca, Henrique; Bártolo, Paulo J

2014-01-01

New micro three-dimensional (3D) scaffolds using biobased unsaturated polyesters (UPs) were prepared by microstereo-thermal-lithography (μSTLG). This advanced processing technique offers indubitable advantages over traditional printing methods. The accuracy and roughness of the 3D structures were evaluated by scanning electron microscopy and infinite focus microscopy, revealing a suitable roughness for cell attachment. UPs were synthesized by bulk polycondensation between biobased aliphatic diacids (succinic, adipic and sebacic acid) and two different glycols (propylene glycol and diethylene glycol) using fumaric acid as the source of double bonds. The chemical structures of the new oligomers were confirmed by proton nuclear magnetic resonance spectra, attenuated total reflectance Fourier transform infrared spectroscopy and matrix assisted laser desorption/ionization-time of flight mass spectrometry. The thermal and mechanical properties of the UPs were evaluated to determine the influence of the diacid/glycol ratio and the type of diacid in the polyester’s properties. In addition an extensive thermal characterization of the polyesters is reported. The data presented in this work opens the possibility for the use of biobased polyesters in additive manufacturing technologies as a route to prepare biodegradable tailor made scaffolds that have potential applications in a tissue engineering area. (paper)

Degradation of Polyester Polyurethane by Bacterial Polyester Hydrolases

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Juliane Schmidt

2017-02-01

Full Text Available Polyurethanes (PU are widely used synthetic polymers. The growing amount of PU used industrially has resulted in a worldwide increase of plastic wastes. The related environmental pollution as well as the limited availability of the raw materials based on petrochemicals requires novel solutions for their efficient degradation and recycling. The degradation of the polyester PU Impranil DLN by the polyester hydrolases LC cutinase (LCC, TfCut2, Tcur1278 and Tcur0390 was analyzed using a turbidimetric assay. The highest hydrolysis rates were obtained with TfCut2 and Tcur0390. TfCut2 also showed a significantly higher substrate affinity for Impranil DLN than the other three enzymes, indicated by a higher adsorption constant K. Significant weight losses of the solid thermoplastic polyester PU (TPU Elastollan B85A-10 and C85A-10 were detected as a result of the enzymatic degradation by all four polyester hydrolases. Within a reaction time of 200 h at 70 °C, LCC caused weight losses of up to 4.9% and 4.1% of Elastollan B85A-10 and C85A-10, respectively. Gel permeation chromatography confirmed a preferential degradation of the larger polymer chains. Scanning electron microscopy revealed cracks at the surface of the TPU cubes as a result of enzymatic surface erosion. Analysis by Fourier transform infrared spectroscopy indicated that the observed weight losses were a result of the cleavage of ester bonds of the polyester TPU.

Kinetics of monomer biodegradation in soil.

Science.gov (United States)

Siotto, Michela; Sezenna, Elena; Saponaro, Sabrina; Innocenti, Francesco Degli; Tosin, Maurizio; Bonomo, Luca; Mezzanotte, Valeria

2012-01-01

In modern intensive agriculture, plastics are used in several applications (i.e. mulch films, drip irrigation tubes, string, clips, pots, etc.). Interest towards applying biodegradable plastics to replace the conventional plastics is promising. Ten monomers, which can be applied in the synthesis of potentially biodegradable polyesters, were tested according to ASTM 5988-96 (standard respirometric test to evaluate aerobic biodegradation in soil by measuring the carbon dioxide evolution): adipic acid, azelaic acid, 1,4-butanediol, 1,2-ethanediol, 1,6-hexanediol, lactic acid, glucose, sebacic acid, succinic acid and terephthalic acid. Eight replicates were carried out for each monomer for 27-45 days. The numerical code AQUASIM was applied to process the CO₂ experimental data in order to estimate values for the parameters describing the different mechanisms occurring to the monomers in soil: i) the first order solubilization kinetic constant, K(sol) (d⁻¹); ii) the first order biodegradation kinetic constant, K(b) (d⁻¹); iii) the lag time in biodegradation, t(lag) (d); and iv) the carbon fraction biodegraded but not transformed into CO₂, Y (-). The following range of values were obtained: [0.006 d⁻¹, 6.9 d⁻¹] for K(sol), [0.1 d⁻¹, 1.2 d⁻¹] for K(b), and [0.32-0.58] for Y; t(lag) was observed for azelaic acid, 1,2-ethanediol, and terephthalic acid, with estimated values between 3.0 e 4.9 d. Copyright © 2011 Elsevier Ltd. All rights reserved.

Development of a biodegradable bone cement

International Nuclear Information System (INIS)

Yusof Abdullah; Nurhaslinda Ee Abdullah; Wee Pee Chai; Norita Mohd Zain

2002-01-01

Biodegradable bone cement is a newly developed bone repair material, which is able to give immediate support to the implant area, and does not obstruct the bone repairing and regeneration process through appropriate biodegradation rate, which is synchronized with the mechanical load it should bear. The purpose of this study is to locally produce biodegradable bone cement using HA as absorbable filler. The cement is composed of an absorbable filler and unsaturated polyester for 100% degradation. Cross-linking effect is achieved through the action of poly (vinyl pyrrol lidone) (PVP) and an initiator. On the other hand, PPF was synthesized using direct esterification method. Characteristics of the bone cement were studied; these included the curing time, cross-linking effect and curing temperature. The products were characterized using X-Ray diffraction (XRD) to perform phase analysis and Scanning Electrons Microscopes to determine the morphology. The physical and mechanical properties of the bone cement were also investigated. The biocompatibility of the bone cement was tested using simulated body physiological solution. (Author)

Microencapsulation of superoxide dismutase into biodegradable microparticles by spray-drying.

Science.gov (United States)

Youan, Bi-Botti Célestin

2004-01-01

The aim of this work was to encapsulate superoxide dismutase (SOD) into biodegradable microparticles by spray-drying technique. The nature of the organic solvent to dissolve the polymer, the method of incorporation of the drug in the organic phase (with or without a surfactant, namely sucrose ester of HLB = 6), the surfactant/polymer ratio, and the nature of the biodegradable polyesters were investigated as formulation variables. The polyesters investigated as matrix were poly(epsilon-caprolactone) (PCL), poly(d, l, lactide-co-glycolide) (PLG-RG756), and poly(d, l-lactide) (PLA-R207) of respective molecular weight 78.2 kDa, 84.8 kDa, and 199.8 kDa. At surfactant/polymer ratio of 1/10, the SOD-retained enzymatic activities were higher (> 95%) for PLG-RG756 and PLA-R207 but relatively lower for the PCL (approximately 85%) probably due to the PCL relatively higher hydrophobicity. The obtained microparticles exhibited average volume mean diameter of 4-10 microm, the smaller for PCL and the larger for PLG-RG756 polymeric matrix. The in vitro release profile showed that SOD was completely (100%) released from PLA-R207 in 48 hr and from PLG-RG756 and PCL within 72 hr. These results showed that spray-drying with incorporation of surfactant such as sucrose ester may efficiently encapsulate SOD into biodegradable microparticles. Such formulations may improve the bioavailability of SOD and similar biopharmaceuticals.

Biodegradation of polyurethane derived from castor oil

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José M. Cangemi

2008-09-01

Full Text Available The aim of this research was to study the biodegradation of a polymer derived from castor oil, which is a renewable, natural material that is a practical alternative for the replacement of traditional polyurethane foams. Due to its molecular structure, which contains polyester segments derived from vegetable oil, the polymeric surface is susceptible to microorganism attack. This study tested the biological degrading agent that was in contact with the microorganisms resulting from microbiological grease degrading agents, when foam was inoculated. Solid-media agar-plate tests were conducted for their potential to evaluate the biodegradation of polymeric particles by specific strains of microorganisms during 216 hours. The growth rate was defined. This technique provides a way of distinguishing the degradation abilities of microorganisms from the degradability of materials.

Enzymatic Synthesis and Characterization of Hydrophilic Sugar Based Polyesters and Their Modification with Stearic Acid

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Muhammad Humayun Bilal

2016-03-01

Full Text Available Biodegradable and hydrophilic functional polyesters were synthesized enzymatically using xylitol or d-sorbitol together with divinyl adipate and lipase B from Candida antartica (CAL-B. The resulting polyesters had pendant OH-groups from their sugar units which were esterified to different degrees with stearic acid chloride. The structure and the degrees of polymerization of the resulting graft copolymers based on poly(xylitol adipate and poly(d-sorbitol adipate were characterized by 1H NMR spectroscopy and SEC. DSC, WAXS and SAXS measurements indicated that a phase separation between polymer backbone and stearoyl side chains occurred in the graft copolymers, and, additionally, the side chains were able to crystallize which resulted in the formation of a lamellar morphology. Additionally, nanoparticles of the graft copolymers in an aqueous environment were studied by DLS and negative stain TEM.

Biodegradable conductive composites of poly(3-hydroxybutyrate and polyaniline nanofibers: Preparation, characterization and radiolytic effects

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2011-01-01

Full Text Available Poly(3-hydroxybutyrate is a biodegradable polyester produced by microorganisms under nutrient limitation conditions. We obtained a biodegradable poly(3-hydroxybutyrate composite having 8 to 55% of chemically in situ polymerized hydrochloric acid-doped polyaniline nanofibers (70-100 nm in diameter. Fourier transform infrared spectroscopy and X-rays diffractometry data did not show evidence of significant interaction between the two components of the nanocomposite, and polyaniline semiconductivity was preserved in all studied compositions. Gamma-irradiation at 25 kGy absorbed dose on the semiconductive composite presenting 28% of doped polyaniline increased its conductivity from 4.6*10-2 to 1.1 S/m, while slightly decreasing its biodegradability. PANI-HCl biodegradation is negligible when compared to PHB biodegradability in an 80 day timeframe. Thus, this unprecedented all-polymer nanocomposite presents, at the same time, semiconductivity and biodegradability and was proven to maintain these properties after gamma irradiation. This new material has many potential applications in biological science, engineering, and medicine.

Poly(ester amide)s based on (L)-lactic acid oligomers and α-amino acids: influence of the α-amino acid side chain in the poly(ester amide)s properties.

Science.gov (United States)

Fonseca, Ana C; Coelho, Jorge F J; Valente, Joana F A; Correia, Tiago R; Correia, Ilídio J; Gil, Maria H; Simões, Pedro N

2013-01-01

Novel biodegradable and low cytotoxic poly(ester amide)s (PEAs) based on α-amino acids and (L)-lactic acid (L-LA) oligomers were successfully synthesized by interfacial polymerization. The chemical structure of the new polymers was confirmed by spectroscopic analyses. Further characterization suggests that the α-amino acid plays a critical role on the final properties of the PEA. L-phenylalanine provides PEAs with higher glass transition temperature, whereas glycine enhances the crystallinity. The hydrolytic degradation in PBS (pH = 7.4) at 37 °C also depends on the α-amino acid, being faster for glycine-based PEAs. The cytotoxic profiles using fibroblast human cells indicate that the PEAs did not elicit an acute cytotoxic effect. The strategy presented in this work opens the possibility of synthesizing biodegradable PEAs with low citotoxicity by an easy and fast method. It is worth to mention also that the properties of these materials can be fine-tuned only by changing the α-amino acid.

Current trends in biodegradable polyhydroxyalkanoates.

Science.gov (United States)

Chanprateep, Suchada

2010-12-01

The microbial polyesters known as polyhydroxyalkanoates (PHAs) positively impact global climate change scenarios by reducing the amount of non-degradable plastic used. A wide variety of different monomer compositions of PHAs has been described, as well as their future prospects for applications where high biodegradability or biocompatibility is required. PHAs can be produced from renewable raw materials and are degraded naturally by microorganisms that enable carbon dioxide and organic compound recycling in the ecosystem, providing a buffer to climate change. This review summarizes recent research on PHAs and addresses the opportunities as well as challenges for their place in the global market. Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Thermal Degradation and Kinetic Parameters of Polyester and Poly(Lactic Acid) Blends Used in Shopping Bags in Brazil

OpenAIRE

Araújo Junior, J.; Magalhães, D; Oliveira, N. A.; Wiebeck, Helio; Matos, J. R.

2014-01-01

In this work, synthetic polyester and poly(lactic acid) blends used as biodegradable shopping plastic bags were studied, together with control samples of polyethylene containing pro-oxidant catalysts (called “oxidegradable bags” in the market). Samples of these materials were weighed and buried in simulated soil for 3 months, and then studied by Thermal Analysis including a non-isothermal kinetic analysis. It was observed that although there was no significant mass loss in the period of the a...

New poly(ester urea) derived from L-leucine: Electrospun scaffolds loaded with antibacterial drugs and enzymes

Energy Technology Data Exchange (ETDEWEB)

Díaz, Angélica; Valle, Luis J. del [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain); Tugushi, David; Katsarava, Ramaz [Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, 13 km. David Aghmashenebeli Alley, Tblisi 0131, Georgia (United States); Puiggalí, Jordi, E-mail: Jordi.Puiggali@upc.edu [Departament d' Enginyeria Química, Universitat Politècnica de Catalunya, Av. Diagonal 647, Barcelona E-08028 (Spain)

2015-01-01

Electrospun scaffolds from an amino acid containing poly(ester urea) (PEU) were developed as promising materials in the biomedical field and specifically in tissue engineering applications. The selected poly(ester urea) was obtained with a high yield and molecular weight by reaction of phosgene with a bis(α-aminoacyl)-α,ω-diol-diester monomer. The polymer having L-leucine, 1,6-hexanediol and carbonic acid units had a semicrystalline character and relatively high glass transition and melting temperatures. Furthermore it was highly soluble in most organic solvents, an interesting feature that facilitated the electrospinning process and the effective incorporation of drugs with bactericidal activity (e.g. biguanide derivatives such as clorhexidine and polyhexamethylenebiguanide) and enzymes (e.g. α-chymotrypsin) that accelerated the degradation process. Continuous micro/nanofibers were obtained under a wide range of processing conditions, being diameters of electrospun fibers dependent on the drug and solvent used. Poly(ester urea) samples were degradable in media containing lipases and proteinases but the degradation rate was highly dependent on the surface area, being specifically greater for scaffolds with respect to films. The high hydrophobicity of new scaffolds had repercussions on enzymatic degradability since different weight loss rates were found depending on how samples were exposed to the medium (e.g. forced or non-forced immersion). New scaffolds were biocompatible, as demonstrated by adhesion and proliferation assays performed with fibroblast and epithelial cells. - Highlights: • Electrospun scaffolds from a biodegradable poly(ester urea) have been prepared. • Scaffolds were effectively loaded with bactericide agents. • Enzymatic degradability of the L-leucine derived poly(ester urea) was demonstrated. • Enzymes that accelerate degradation were incorporated in the electrospun fibers. • Cell adhesion/proliferation assays demonstrated

Lipase biocatalysis for useful biodegradable products

Energy Technology Data Exchange (ETDEWEB)

Linko, Y Y; Wang, Zhuo Lin; Uosukainen, E; Seppaelae, J [Helsinki Univ. of Technology, Espoo (Finland); Laemsae, M [Raisio Group Oil Milling Industry, Raisio (Finland)

1997-12-31

It was shown that lipases can be used as biocatalysts in the production of useful biodegradable compounds such as 1-butyl oleate by direct esterification of butanol and oleic acid to decrease viscosity of biodiesel in winter use. By enzymic transesterification, a mixture of 2-ethyl-1-hexyl esters from rapeseed oil fatty acids can be obtained in good yields for use as a solvent, and of trimethylolpropane esters for use as a lubricant. Finally, it was demonstrated that polyesters with a mass average molar mass in excess of 75,000 g mol{sup -}1 can be obtained by esterification or transesterification by using lipase as biocatalyst. (author) (3 refs.)

Lipase biocatalysis for useful biodegradable products

Energy Technology Data Exchange (ETDEWEB)

Linko, Y.Y.; Wang, Zhuo Lin; Uosukainen, E.; Seppaelae, J. [Helsinki Univ. of Technology, Espoo (Finland); Laemsae, M. [Raisio Group Oil Milling Industry, Raisio (Finland)

1996-12-31

It was shown that lipases can be used as biocatalysts in the production of useful biodegradable compounds such as 1-butyl oleate by direct esterification of butanol and oleic acid to decrease viscosity of biodiesel in winter use. By enzymic transesterification, a mixture of 2-ethyl-1-hexyl esters from rapeseed oil fatty acids can be obtained in good yields for use as a solvent, and of trimethylolpropane esters for use as a lubricant. Finally, it was demonstrated that polyesters with a mass average molar mass in excess of 75,000 g mol{sup -}1 can be obtained by esterification or transesterification by using lipase as biocatalyst. (author) (3 refs.)

Biodegradable magnesium alloys for orthopaedic applications: A review on corrosion, biocompatibility and surface modifications.

Science.gov (United States)

Agarwal, Sankalp; Curtin, James; Duffy, Brendan; Jaiswal, Swarna

2016-11-01

Magnesium (Mg) and its alloys have been extensively explored as potential biodegradable implant materials for orthopaedic applications (e.g. Fracture fixation). However, the rapid corrosion of Mg based alloys in physiological conditions has delayed their introduction for therapeutic applications to date. The present review focuses on corrosion, biocompatibility and surface modifications of biodegradable Mg alloys for orthopaedic applications. Initially, the corrosion behaviour of Mg alloys and the effect of alloying elements on corrosion and biocompatibility is discussed. Furthermore, the influence of polymeric deposit coatings, namely sol-gel, synthetic aliphatic polyesters and natural polymers on corrosion and biological performance of Mg and its alloy for orthopaedic applications are presented. It was found that inclusion of alloying elements such as Al, Mn, Ca, Zn and rare earth elements provides improved corrosion resistance to Mg alloys. It has been also observed that sol-gel and synthetic aliphatic polyesters based coatings exhibit improved corrosion resistance as compared to natural polymers, which has higher biocompatibility due to their biomimetic nature. It is concluded that, surface modification is a promising approach to improve the performance of Mg-based biomaterials for orthopaedic applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Intensification of polyester synthesis by continuous reactive distillation

NARCIS (Netherlands)

Shah, M.R.

2011-01-01

The thesis starts with a brief overview of unsaturated polyesters. In particular, the usage of raw materials, the application of unsaturated polyester resins, and, the worldwide supply and demand of the unsaturated polyester resins are discussed. Unsaturated polyester is traditionally produced in a

Electrospinning of microbial polyester for cell culture

Energy Technology Data Exchange (ETDEWEB)

Kwon, Oh Hyeong [Department of Polymer Science and Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of); Lee, Ik Sang [Department of Polymer Science and Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of); Ko, Young-Gwang [Department of Polymer Science and Engineering, Kumoh National Institute of Technology, 1 Yangho-dong, Gumi, Gyeongbuk 730-701 (Korea, Republic of); Meng, Wan [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Jung, Kyung-Hye [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Kang, Inn-Kyu [Department of Polymer Science, Kyungpook National University, 1370 Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Ito, Yoshihiro [Kanagawa Academy of Science and Technology, KSP East 309, Sakado 3-2-1, Takatsu-ku, Kawasaki 213-0012 (Japan)

2007-03-01

Biodegradable and biocompatible poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a copolymer of microbial polyester, was fabricated as a nanofibrous mat by electrospinning. The specific surface area and the porosity of electrospun PHBV nanofibrous mat were determined. When the mechanical properties of flat film and electrospun PHBV nanofibrous mats were investigated, both the tensile modulus and strength of electrospun PHBV were less than those of cast PHBV film. However, the elongation ratio of nanofiber mat was higher than that of the cast film. The structure of electrospun nanofibers using PHBV-trifluoroethanol solutions depended on the solution concentrations. When x-ray diffraction patterns of bulk PHBV before and after electrospinning were compared, the crystallinity of PHBV was not significantly affected by the electrospinning process. Chondrocytes adhered and grew on the electrospun PHBV nanofibrous mat better than on the cast PHBV film. Therefore, the electrospun PHBV was considered to be suitable for cell culture.

40 CFR 721.8082 - Polyester polyurethane acrylate.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyester polyurethane acrylate. 721... Substances § 721.8082 Polyester polyurethane acrylate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as polyester polyurethane acrylate...

Nanomembranes and Nanofibers from Biodegradable Conducting Polymers

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Jordi Puiggalí

2013-09-01

Full Text Available This review provides a current status report of the field concerning preparation of fibrous mats based on biodegradable (e.g., aliphatic polyesters such as polylactide or polycaprolactone and conducting polymers (e.g., polyaniline, polypirrole or polythiophenes. These materials have potential biomedical applications (e.g., tissue engineering or drug delivery systems and can be combined to get free-standing nanomembranes and nanofibers that retain the better properties of their corresponding individual components. Systems based on biodegradable and conducting polymers constitute nowadays one of the most promising solutions to develop advanced materials enable to cover aspects like local stimulation of desired tissue, time controlled drug release and stimulation of either the proliferation or differentiation of various cell types. The first sections of the review are focused on a general overview of conducting and biodegradable polymers most usually employed and the explanation of the most suitable techniques for preparing nanofibers and nanomembranes (i.e., electrospinning and spin coating. Following sections are organized according to the base conducting polymer (e.g., Sections 4–6 describe hybrid systems having aniline, pyrrole and thiophene units, respectively. Each one of these sections includes specific subsections dealing with applications in a nanofiber or nanomembrane form. Finally, miscellaneous systems and concluding remarks are given in the two last sections.

Experimental Evaluation of Polyester and Epoxy–Polyester Powder Coatings in Aggressive Media

Directory of Open Access Journals (Sweden)

Ivan Stojanović

2018-03-01

Full Text Available Protective coatings are the most widely used corrosion protection method for construction materials in different environmental conditions. They isolate metals from aggressive media, making the structure more durable. Today, alongside good anti-corrosive properties, coatings need to be safe for the environment and harmless to those who apply them. The high volatile organic compound (VOC content in conventional solvent-borne coatings presents a huge ecological problem. A solution for indispensable solvent emission reduction is the application of powder coatings. This study evaluates the corrosion performance and surface morphology of polyester and epoxy–polyester powder coatings. Electrochemical impedance spectroscopy (EIS, open circuit potential (OCP measurement, salt spray chamber and humidity chamber testing followed by adhesion testing were used to investigate the protective properties of powder coatings. Scanning electron microscope (SEM with energy-dispersive X-ray spectroscopy (EDX was used to analyse the surface morphology and chemical composition, whereas the microstructure and coating uniformity were determined by optical microscope examination. The research revealed a negative influence of coating surface texture on coating thickness and consequently a lack of barrier and adhesion properties. The epoxy–polyester powder coating showed a better performance than the polyester coating. All tested coatings showed uniform structure.

Application of eco-friendly antimicrobial finish butea monosperma leaves on fabric properties of polyester and cotton/polyester

International Nuclear Information System (INIS)

Sadaf, S.; Saeed, M.; Kalsoom, S.; Saeed, M.

2017-01-01

The study was aimed to check the effect of eco-friendly antimicrobial finish on 100% polyester and 50/50 cotton/polyester woven fabrics. The leaves' extract of Butea monosperma was used as an eco-friendly antimicrobial finish. The fabric was first desized, scoured, bleached and washed then antimicrobial finish was applied by using pad dry cure method. The aesthetic, comfort and mechanical fabrics properties were checked before and after applying antimicrobial finish. Under aesthetic property stiffness and smoothness appearance was checked, under comfort related property absorbency and air permeability was checked and under mechanical property tear and tensile strength was checked. The antimicrobial finish was checked by using ASTEM E2149 Shake Flask method. The AATCC and ISO standard testing methods were used for checking fabric properties. One way ANOVA statistical test was applied for analysis of results. Antimicrobial finish has increased aesthetic (stiffness, smoothness appearance), comfort (absorbency, air permeability) and mechanical (tensile and tear strengths) properties of polyester and cotton/polyester fabrics. The antimicrobial finish was effective on both 100% polyester and 50/50 cotton/polyester fabrics up to 25 washes. This study is beneficial to medical industry, paramedical staff, sports wears, home furnishing as well as common people. (author)

Co-Expression of ORFCma with PHB Depolymerase (PhaZCma ) in Escherichia coli Induces Efficient Whole-Cell Biodegradation of Polyesters.

Science.gov (United States)

Lee, Ming-Chieh; Liu, En-Jung; Yang, Cheng-Han; Hsiao, Li-Jung; Wu, Tzong-Ming; Li, Si-Yu

2018-04-01

Whole-cell degradation of polyesters not only avoids the tedious process of enzyme separation, but also allows the degraded product to be reused as a carbon source. In this study, Escherichia coli BL21(DE3) harboring phaZ Cma , a gene encoding poly(3-hydroxybutyrate) (PHB) depolymerase from Caldimonas manganoxidans, is constructed. The extra-cellular fraction of E. coli/pPHAZ exhibits a fast PHB degradation rate where it only took 35 h to completely degrade PHB films, while C. manganoxidans takes 81 h to do the same. The co-expression of ORF Cma (a putative periplasmic substrate binding protein that is within the same operon of phaZ Cma ) further improves the PHB degradation. While 28 h is needed for E. coli/pPHAZ to cause an 80% weight loss in PHB films, E. coli/pORFPHAZ needs only 21 h. Furthermore, it is able to degrade at-least four different polyesters, PHB, poly(lactic acid) (PLA), polycaprolactone (PCL), and poly(butylene succinate-co-adipate) (PBSA). Testing of the time course of 3-hydroxybutyrate concentration and the turbidity of the degradation solutions over time shows that PhaZ Cma has both exo- and endo-enzymatic activity. The whole-cell E. coli/pORFPHAZ can be used for recycling various polyesters while ORF Cma can potentially be a universal element for enhancing the secretion of recombinant protein. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Functional bio-based polyesters by enzymatic polymerization

DEFF Research Database (Denmark)

Daugaard, Anders Egede; Hoffmann, Christian; Andersen, Christian

During recent years enzymatic polymerization has become increasingly popular as an alternative to classical polyesterification processes. The high regioselectivity observed for lipases permits preparation of novel polyesters with a high number of functional groups.1 This is particularly interesting...... polymerization was applied to prepare functional water soluble polyesters based on dimethyl itaconate and poly(ethyleneglycol).2 The monomer permits postfunctionalization using thiol-ene chemistry or aza-michael additions, which was used to illustrate the possibilites of preparing functional hydrogels. Hydrogels...... based on the polyesters were shown to be degradable and could be prepared either from the pure polyester or from prefunctionalized polyesters, though the thiol-ene reactions were found to be less effective. Since then a new monomer, trans-2,5-dihydroxy-3-pentenoic acid methyl ester (DPM) has been...

Polyester projects for India, Pakistan

International Nuclear Information System (INIS)

Siddiqi, R.

1993-01-01

India's Indo Rama Synthetics (Bombay) is planning a $186-million integrated polyester fiber and filament complex at Nagpur, Maharashtra. The complex will have annual capacities for 38,000 m.t. of polyester chips by polycondensation, 25,000 m.t. of polyester staple fiber, and 12,000 m.t. of polyester blended yarn. The company is negotiating with the main world suppliers of polycondensation technology. The first stage of the project is slated to begin production by the end of this year and be fully completed by 1994. In Pakistan, National Fibers Ltd. (PNF; Karachi) has signed a deal with Zimmer (Frankfurt) for technology, procurement, construction, and support work to expand polyester staple fiber capacity from 14,000 m.t./year to 52,000 m.t./year. The technology involves a continuous polymerization process. The project also calls for improvements to PNF's existing batch plant. It is scheduled for completion by the end of 1994. Total cost of the project is estimated at Rs1.745 billion ($70 million), out of which the foreign exchange component is Rs1.05 billion. The Islamic Development Bank (Jeddah; Saudi Arabia) has already approved a $27-million slice of the financing, while the balance of the foreign exchange loan is being arranged through suppliers credit. Local currency loans will be provided by other financial institutions in Pakistan

Propagation of polarized light through azobenzene polyester films

DEFF Research Database (Denmark)

Nedelchev, L; Matharu, A; Nikolova, Ludmila

2002-01-01

When elliptically polarized light of appropriate wavelength Corresponding to trans-cis-trans isomerisation process is incident on thin films of azobenzene polyesters, a helical structure is induced. We investigate the propagation of the exciting light beam (self-induced) as well as a probe light...... beam outside the absorption band through the polyester films. Investigations are carried out in one amorphous and one liquid crystalline polyester. We show that amorphous polyester after irradiation behaves like classical helical material....

Optical and mechanical properties of UV-weathered biodegradable PHBV/PBAT nanocomposite films containing halloysite nanotubes

Science.gov (United States)

Scarfato, P.; Avallone, E.; Acierno, D.; Russo, P.

2014-05-01

Recently, the increasing use of plastics, stringent environmental issues and the awareness of the progressive reduction of available petrochemical resources have ever more guided the research interest towards the investigation and development of innovative materials intrinsically biodegradable or derived from renewable sources, and generally known as bio-based polymers. Amongst the biobased and biodegradable polymers, many investigations were reported in literature about a family of polyesters known as poly(hydroxyalkanoate)s (PHAs), one of whose most prevalent is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). In this context, here we report the results of a photo-degradation study performed on biodegradable blown film samples based on a commercial grade PHBV/PBAT formulation. The films, subjected to photo-oxidative weathering in a climatic chamber under UV exposure, were systematically analysed in order to check the chemico-physical changes induced by the aging protocol, taking the as-produced films as the reference materials.

Bacterial production of the biodegradable plastics polyhydroxyalkanoates.

Science.gov (United States)

Urtuvia, Viviana; Villegas, Pamela; González, Myriam; Seeger, Michael

2014-09-01

Petroleum-based plastics constitute a major environmental problem due to their low biodegradability and accumulation in various environments. Therefore, searching for novel biodegradable plastics is of increasing interest. Microbial polyesters known as polyhydroxyalkanoates (PHAs) are biodegradable plastics. Life cycle assessment indicates that PHB is more beneficial than petroleum-based plastics. In this report, bacterial production of PHAs and their industrial applications are reviewed and the synthesis of PHAs in Burkholderia xenovorans LB400 is described. PHAs are synthesized by a large number of microorganisms during unbalanced nutritional conditions. These polymers are accumulated as carbon and energy reserve in discrete granules in the bacterial cytoplasm. 3-hydroxybutyrate and 3-hydroxyvalerate are two main PHA units among 150 monomers that have been reported. B. xenovorans LB400 is a model bacterium for the degradation of polychlorobiphenyls and a wide range of aromatic compounds. A bioinformatic analysis of LB400 genome indicated the presence of pha genes encoding enzymes of pathways for PHA synthesis. This study showed that B. xenovorans LB400 synthesize PHAs under nutrient limitation. Staining with Sudan Black B indicated the production of PHAs by B. xenovorans LB400 colonies. The PHAs produced were characterized by GC-MS. Diverse substrates for the production of PHAs in strain LB400 were analyzed. Copyright © 2014 Elsevier B.V. All rights reserved.

Polystyrene/Hyperbranched Polyester Blends and Reactive Polystyrene/Hyperbranched Polyester Blends

National Research Council Canada - National Science Library

Mulkern, Thomas

1999-01-01

.... In this work, the incorporation of HBPs in thermoplastic blends was investigated. Several volume fractions of hydroxyl functionalized hyperbranched polyesters were melt blended with nonreactive polystyrene (PS...

Biodegradable charged polyester-based vectors (BCPVs) as an efficient non-viral transfection nanoagent for gene knockdown of the BCR-ABL hybrid oncogene in a human chronic myeloid leukemia cell line

Science.gov (United States)

Yang, Chengbin; Panwar, Nishtha; Wang, Yucheng; Zhang, Butian; Liu, Maixian; Toh, Huiting; Yoon, Ho Sup; Tjin, Swee Chuan; Chong, Peter Han Joo; Law, Wing-Cheung; Chen, Chih-Kuang; Yong, Ken-Tye

2016-04-01

First-line therapy of chronic myelogenous leukemia (CML) has always involved the use of BCR-ABL tyrosine-kinase inhibitors which is associated with an abnormal chromosome called Philadelphia chromosome. Although the overall survival rate has been improved by the current therapeutic regime, the presence of resistance has resulted in limited efficacy. In this study, an RNA interference (RNAi)-based therapeutic regime is proposed with the aim to knockdown the BCR-ABL hybrid oncogene using small interfering RNA (siRNA). The siRNA transfection rates have usually been limited due to the declining contact probability among polyplexes and the non-adherent nature of leukemic cells. Our work aims at addressing this limitation by using a biodegradable charged polyester-based vector (BCPV) as a nanocarrier for the delivery of BCR-ABL-specific siRNA to the suspension culture of a K562 CML cell line. BCR-ABL siRNAs were encapsulated in the BCPVs by electrostatic force. Cell internalization was facilitated by the BCPV and assessed by confocal microscopy and flow cytometry. The regulation of the BCR-ABL level in K562 cells as a result of RNAi was analyzed by real-time polymerase chain reaction (RT-PCR). We observed that BCPV was able to form stable nanoplexes with siRNA molecules, even in the presence of fetal bovine serum (FBS), and successfully assisted in vitro siRNA transfection in the non-adherent K562 cells. As a consequence of downregulation of BCR-ABL, BCPV-siRNA nanoplexes inhibited cell proliferation and promoted cell apoptosis. All results were compared with a commercial transfection reagent, Lipofectamine2000™, which served as a positive control. More importantly, this class of non-viral vector exhibits biodegradable features and negligible cytotoxicity, thus providing a versatile platform to deliver siRNA to non-adherent leukemia cells with high transfection efficiency by effectively overcoming extra- and intra-cellular barriers. Due to the excellent in vitro

Synthetic polyester-hydrolyzing enzymes from thermophilic actinomycetes.

Science.gov (United States)

Wei, Ren; Oeser, Thorsten; Zimmermann, Wolfgang

2014-01-01

Thermophilic actinomycetes produce enzymes capable of hydrolyzing synthetic polyesters such as polyethylene terephthalate (PET). In addition to carboxylesterases, which have hydrolytic activity predominantly against PET oligomers, esterases related to cutinases also hydrolyze synthetic polymers. The production of these enzymes by actinomycetes as well as their recombinant expression in heterologous hosts is described and their catalytic activity against polyester substrates is compared. Assays to analyze the enzymatic hydrolysis of synthetic polyesters are evaluated, and a kinetic model describing the enzymatic heterogeneous hydrolysis process is discussed. Structure-function and structure-stability relationships of actinomycete polyester hydrolases are compared based on molecular dynamics simulations and recently solved protein structures. In addition, recent progress in enhancing their activity and thermal stability by random or site-directed mutagenesis is presented. © 2014 Elsevier Inc. All rights reserved.

Biodegradable electroactive materials for tissue engineering applications

Science.gov (United States)

Guimard, Nathalie Kathryn

This dissertation focuses on the development of biomaterials that could be used to enhance the regeneration of severed peripheral nerves. These materials were designed to be electroactive, biodegradable, and biocompatible. To render the materials electroactive the author chose to incorporate conducting polymer (CP) units into the materials. Because CPs are inherently non-degradable, the key challenge was to create a CP-based material that was also biodegradable. Two strategies were explored to generate a biodegradable CP-based material. The first strategy centered around the incorporation of both electroactive and biodegradable subunits into a copolymer system. In the context of this approach, two bis(methoxyquaterthiophene)-co-adipic acid polyester (QAPE) analogues were successfully synthesized, one through polycondensation (giving undoped QAPE) and the second through oxidative polymerization (giving doped QAPE-2). QAPE was found to be electroactive by cyclic voltammetry, bioerodible, and cytocompatible with Schwann cells. QAPE was doped with ferric perchlorate, although only a low doping percentage was realized (˜8%). Oxidative polymerization of a bis(bithiophene) adipate permitted the direct synthesis of doped QAPE-2, which was found to have a higher doping level (˜24%). The second strategy pursued with the goal of generating an electroactive biodegradable material involved covalently immobilizing low molecular weight polythiophene chains onto the surface of crosslinked hyaluronic acid (HA) films. HA films are not only biodegradable and biocompatible, but they also provide mechanical integrity to bilayer systems. Dicyclocarbodiimide coupling of carboxylic acids to HA alcohol groups was used to functionalize HA films. The HA-polythiophene composite is still in the early stages of development. However, to date, thiophene has been successfully immobilized at the surface of HA films with a high degree of substitution. The author has also shown that thiophene

Biodegradable polyesters for veterinary drug delivery systems: Characterization, in vitro degradation and release behavior of Oligolactides and Polytartrate

OpenAIRE

Schliecker, Gesine

2004-01-01

This thesis deals with the degradation and release behavior of aliphatic polyesters with special respect to the influence of oligomers on the degradation rate and the potential use of these biomaterials for the development of veterinary drug delivery systems. In Chapter 1 the animal health care market is introduced with regard to opportunities and challenges of veterinary drug delivery systems. . In the second part of this chapter...

Biodegradable composites from polyester and sugar beet pulp with antimicrobial coating for food packaging

Science.gov (United States)

Totally biodegradable, double-layered antimicrobial composite Sheets were introduced for food packaging. The substrate layers of the sheets were prepared from poly (lactic acid) (PLA) and sugar beet pulp (SBP) or poly (butylene adipate-co-terephthalate (PBAT) and SBP by a twin-screw extruder. The ac...

Blends of polyester ionomers with polar polymers: Interactions, reactions, and compatibilization

Science.gov (United States)

Boykin, Timothy Lamar

The compatibility of amorphous and semicrystalline polyester ionomers with various polar polymers (i.e., polyesters and polyamides) has been investigated for their potential use as minor component compatibilizers. The degree of compatibility (i.e., ranging from incompatible to miscible) between the polyester ionomers and the polar polymers was determined by evaluating the effect of blend composition on the melting behavior and phase behavior of binary blends. In addition, the origin of compatibility and/or incompatibility for each of the binary blends (i.e., polyamide/ionomer and polyester/ionomer) was determined by evaluating blends prepared by both solution and melt mixed methods. Subsequent to investigation of the binary blends, the effect of polyester ionomer addition on the compatibility of polyamide/polyester blends was investigated by evaluating the mechanical properties and phase morphology of ionomer compatibilized polyamide/polyester blends. Polyester ionomers (amorphous and semicrystalline) were shown to exhibit a high degree of compatibility (even miscibility) with polyamides, such as nylon 6,6 (N66). Compatibility was attributed to specific interactions between the metal counterion of the polyester ionomer and the amide groups of N66. The degree of compatibility (or miscibility) was shown to be dependent on the counterion type of the ionomer, with the highest degree exhibited by blends containing the divalent form of the polyester ionomers. Although polyester ionomers were shown to exhibit incompatibility with both poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT), increasing the time of melt processing significantly enhanced the compatibility of the polyester ionomers with both PET and PBT. The observed enhancement in compatibility was attributed to ester-ester interchange between the polyester blend components, which was confirmed by NMR spectroscopy. The addition of polyester ionomers as a minor component compatibilizer (i

Preparation and applications of wood-polyester composites

International Nuclear Information System (INIS)

Czvikovszky, T.

1982-01-01

Optimum processing parameters were searched for the pilot-scale production of wood-polyester composites by irradiation of resin-impregnated wood material. The radiation initiation of the following systems were examined in wood and without wood matrix: methyl methacrylate, mixture of styrene and acrylonitryle, and their combination with unsaturated polyester. In the most cases the over-all rate of the complete polymerization process in wood matrix is proportional to the square root of the initiation rate. The parameters of the radiation technology of wood-polyester composites have been determined, using 260 TBq (7 kCi) 60 Co radiation source. A pilot plant has been constructed using an underwater irradiation system of 1.85 PBq (50 kCi) 60 Co. The successful production rate of 200 kg wood-polyester composite per day, as well as the application tests have demonstrated the technical feasibility of this new structural material. (author)

Biodegradable magnesium alloys for orthopaedic applications: A review on corrosion, biocompatibility and surface modifications

Energy Technology Data Exchange (ETDEWEB)

Agarwal, Sankalp [Centre for Research in Engineering and Surface Technology, FOCAS Institute, Dublin Institute of Technology (Ireland); School of Food Science and Environmental Health, Cathal Brugha Street, Dublin Institute of Technology (Ireland); Curtin, James [School of Food Science and Environmental Health, Cathal Brugha Street, Dublin Institute of Technology (Ireland); Duffy, Brendan [Centre for Research in Engineering and Surface Technology, FOCAS Institute, Dublin Institute of Technology (Ireland); Jaiswal, Swarna, E-mail: swarna.jaiswal@dit.ie [Centre for Research in Engineering and Surface Technology, FOCAS Institute, Dublin Institute of Technology (Ireland)

2016-11-01

Magnesium (Mg) and its alloys have been extensively explored as potential biodegradable implant materials for orthopaedic applications (e.g. Fracture fixation). However, the rapid corrosion of Mg based alloys in physiological conditions has delayed their introduction for therapeutic applications to date. The present review focuses on corrosion, biocompatibility and surface modifications of biodegradable Mg alloys for orthopaedic applications. Initially, the corrosion behaviour of Mg alloys and the effect of alloying elements on corrosion and biocompatibility is discussed. Furthermore, the influence of polymeric deposit coatings, namely sol-gel, synthetic aliphatic polyesters and natural polymers on corrosion and biological performance of Mg and its alloy for orthopaedic applications are presented. It was found that inclusion of alloying elements such as Al, Mn, Ca, Zn and rare earth elements provides improved corrosion resistance to Mg alloys. It has been also observed that sol-gel and synthetic aliphatic polyesters based coatings exhibit improved corrosion resistance as compared to natural polymers, which has higher biocompatibility due to their biomimetic nature. It is concluded that, surface modification is a promising approach to improve the performance of Mg-based biomaterials for orthopaedic applications. - Highlights: • The Mg based alloys are promising candidates for orthopaedic applications. • The rapid corrosion of Mg can affect human cells, and causes infection and implant failure. • The various physiological factors and Mg alloying elements affect the corrosion and mechanical properties of implants. • The polymeric deposit coatings enhance the corrosion resistance and biocompatibility.

Biodegradable magnesium alloys for orthopaedic applications: A review on corrosion, biocompatibility and surface modifications

International Nuclear Information System (INIS)

Agarwal, Sankalp; Curtin, James; Duffy, Brendan; Jaiswal, Swarna

2016-01-01

Magnesium (Mg) and its alloys have been extensively explored as potential biodegradable implant materials for orthopaedic applications (e.g. Fracture fixation). However, the rapid corrosion of Mg based alloys in physiological conditions has delayed their introduction for therapeutic applications to date. The present review focuses on corrosion, biocompatibility and surface modifications of biodegradable Mg alloys for orthopaedic applications. Initially, the corrosion behaviour of Mg alloys and the effect of alloying elements on corrosion and biocompatibility is discussed. Furthermore, the influence of polymeric deposit coatings, namely sol-gel, synthetic aliphatic polyesters and natural polymers on corrosion and biological performance of Mg and its alloy for orthopaedic applications are presented. It was found that inclusion of alloying elements such as Al, Mn, Ca, Zn and rare earth elements provides improved corrosion resistance to Mg alloys. It has been also observed that sol-gel and synthetic aliphatic polyesters based coatings exhibit improved corrosion resistance as compared to natural polymers, which has higher biocompatibility due to their biomimetic nature. It is concluded that, surface modification is a promising approach to improve the performance of Mg-based biomaterials for orthopaedic applications. - Highlights: • The Mg based alloys are promising candidates for orthopaedic applications. • The rapid corrosion of Mg can affect human cells, and causes infection and implant failure. • The various physiological factors and Mg alloying elements affect the corrosion and mechanical properties of implants. • The polymeric deposit coatings enhance the corrosion resistance and biocompatibility.

Synthesis and characterization of polyesters from renewable cardol ...

African Journals Online (AJOL)

Bulletin of the Chemical Society of Ethiopia ... The preparation and thermal characteristics of new polyesters from cardol, a renewable monomer ... All prepared polyesters were insoluble in common laboratory solvents at room temperature.

Bio-plastic (P-3HB-co-3HV) from Bacillus circulans (MTCC 8167) and its biodegradation.

Science.gov (United States)

Phukon, Pinkee; Saikia, Jyoti Prasad; Konwar, Bolin Kumar

2012-04-01

Polyhydroxyalkanoates (PHAs) are naturally occurring polyesters synthesized by bacteria for carbon and energy storage and it has commercial potential as bioplastic. The bacterial species Bacillus circulans MTCC 8167, isolated from crude oil contaminated soil, can efficiently produce medium chain length polyhydroxyalkanoates (P-3HB-co-3HV) from cheap carbon sources like dextrose. The molecular mass of P-3HB-co-3HV was reported as 5.1×10(4)Da with polydispersity index of 1.21 by gel permeation chromatography. In the present investigation different bacteria and fungi species were used for testing the biodegradability of the extracted polymer. The FTIR spectra of the biodegraded PHBV film showed a decrease in the peak from 1735 cm(-1) (untreated film) to 1675 cm(-1), and disappearance of a peak present in the control at 2922 cm(-1) indicating the breakdown of ester (>C=O) or O-R group and -C=H bond, respectively. From biodegradability testing, the tested microorganisms were found to have decisive contribution to the biodegradation of P-3HB-co-3HV polymer. Copyright © 2011 Elsevier B.V. All rights reserved.

Holographic recording in thiophene-based polyester

DEFF Research Database (Denmark)

Matharu, Avtar Singh; Chambers-Asman, David; Jeeva, Shehzad

2008-01-01

The synthesis and optical data storage properties of a side-chain thiophene-phenyl azopolyester ThPhAzoP.ol is reported. The polyester is derived from diphenyl tetradecanedioate and a thiophenebased liquid crystalline diol which exhibits a short-lived enantiotropic SmA phase (Cryst 177.7 SmA 180.......4 I). The polyester ThPhAzoPol exhibits amorphous (Tg, 78.6 DC), crystalline and liquid crystalline character as evidenced by differential scanning calorimetry and thermal polarising microscopy. A grainy texture, which is thermally reversible, with increasing birefringence on cooling from...... the isotropic melt is observed. The polyester is amenable to optical data storage, showing efficient induced anisotropy, which is stable at room temperature. Polarisation gratings can be inscribed using orthogonally.linear and circularly polarised light to good effect (>10/0) and surface relief gratings...

Rheological Behavior of Bentonite-Polyester Dispersions

Science.gov (United States)

Abu-Jdayil, Basim; Al-Omari, Salah Addin

2013-07-01

The rheological behavior of a bentonite clay dispersed in unsaturated polyester was investigated. The effects of the solid content and particle size on the steady and transient rheological properties of the dispersions were studied. In addition, two types of bentonite with different Na+/Ca+2 ratio were used in this study. The Herschel-Bulkley and the Weltman models were used to describe the apparent viscosity of the bentonite-polyester composite in relation to the shear rate and shearing time. The bentonite-polyester dispersions were found to exhibit both Newtonian and non-Newtonian behavior. The transition from a Newtonian to a Bingham plastic and then to a shear-thinning material with a yield stress was found to depend on the solid concentration, the particle size, and the type of bentonite. At a low solid content, the apparent viscosity of the bentonite dispersion increased linearly with solid concentration. But a dramatic increase in the apparent viscosity beyond a solid content of 20 wt.% was observed. On the other hand, a thixotropic behavior was detected in bentonite-polyester dispersions with a high solid content and a low particle size. However, this behavior was more pronounced in dispersions with a high Na+/Ca+2 ratio.

Light scattering of thin azobenzene side-chain polyester layers

DEFF Research Database (Denmark)

Kerekes, Á.; Lörincz, E.; Ramanujam, P.S.

2002-01-01

Light scattering properties of liquid crystalline and amorphous azobenzene side-chain polyester layers used for optical data storage were examined by means of transmissive scatterometry. Comparative experiments show that the amorphous polyester has significantly lower light scattering...... characteristics than the liquid crystalline polyester. The amorphous samples have negligible polarization part orthogonal to the incident beam. the liquid crystalline samples have relative high orthogonal polarization part in light scattering, The light scattering results can be used to give a lower limit...... for the domain size in thin liquid crystalline polyester layers being responsible for the dominant light scattering. The characteristic domain Sizes obtained from the Fourier transformation of polarization microscopic Pictures confirm these values....

Studies in reactive extrusion processing of biodegradable polymeric materials

Science.gov (United States)

Balakrishnan, Sunder

Various reaction chemistries such as Polymerization, Polymer cross-linking and Reactive grafting were investigated in twin-screw extruders. Poly (1,4-dioxan-2-one) (PPDX) was manufactured in melt by the continuous polymerization of 1,4-dioxan-2-one (PDX) monomer in a twin-screw extruder using Aluminum tri-sec butoxide (ATSB) initiator. Good and accurate control over molecular weight was obtained by controlling the ratio of monomer to initiator. A screw configuration consisting of only conveying elements was used for the polymerization. The polymerization reaction was characterized by a monomer-polymer dynamic equilibrium, above the melting temperature of the polymer, limiting the equilibrium conversion to 78-percent. Near complete (˜100-percent) conversion was obtained on co-polymerizing PDX monomer with a few mol-percent (around 8-percent) Caprolactone (CL) monomer in a twin-screw extruder using ATSB initiator. The co-polymers exhibited improved thermal stability with reduction in glass transition temperature. The extruder was modeled as an Axial Dispersed Plug Flow Reactor for the polymerization of CL monomer using Residence Time Distribution (RTD) Analysis. The model provided a good fit to the experimental RTD and conversion data. Aliphatic and aliphatic-aromatic co-polyesters, namely Polycaprolactone (PCL) and Poly butylenes (adipate-co-terephthalate) (Ecoflex) were cross-linked in a twin-screw extruder using radical initiator to form micro-gel reinforced biodegradable polyesters. Cross-linked Ecoflex was further extrusion blended with talc to form blends suitable to be blown into films. A screw configuration consisting of conveying and kneading elements was found to be effective in dispersion of the talc particles (5--10 microns) in the polyester matrix. While the rates of crystallization increased for the talc filled polyester blends, overall crystallinity reduced. Mechanical, tear and puncture properties of films made using the talc filled polyester blends

Radiation processed composite materials of wood and elastic polyester resins

International Nuclear Information System (INIS)

Tapolcai, I.; Czvikovszky, T.

1983-01-01

The radiation polymerization of multifunctional unsaturated polyester-monomer mixtures in wood forms interpenetrating network system. The mechanical resistance (compression, abrasion, hardness, etc.) of these composite materials are generally well over the original wood, however the impact strength is almost the same or even reduced, in comparison to the wood itself. An attempt is made using elastic polyester resins to produced wood-polyester composite materials with improved modulus of elasticity and impact properties. For the impregnation of European beech wood two types of elastic unsaturated polyester resins were used. The exothermic effect of radiation copolymerization of these resins in wood has been measured and the dose rate effects as well as hardening dose was determined. Felxural strength and impact properties were examined. Elastic unsaturated polyester resins improved the impact strength of wood composite materials. (author)

Isohexide and Sorbitol-Derived, Enzymatically Synthesized Renewable Polyesters with Enhanced Tg.

Science.gov (United States)

Gustini, Liliana; Lavilla, Cristina; de Ilarduya, Antxon Martínez; Muñoz-Guerra, Sebastián; Koning, Cor E

2016-10-10

Sugar-based polyesters derived from sorbitol and isohexides were obtained via solvent-free enzymatic catalysis. Pendant hydroxyl groups, coming from the sorbitol units, were present along the polyester backbone, whereas the two isohexides, namely, isomannide and isoidide dimethyl ester monomers, were selected to introduce rigidity into the polyester chains. The feasibility of incorporating isomannide as a diol compared to the isoidide dimethyl ester as acyl-donor via lipase-catalyzed polycondensation was investigated. The presence of bicyclic units resulted in enhanced T g with respect to the parent sorbitol-containing polyester lacking isohexides. The different capability of the two isohexides to boost the thermal properties confirmed the more flexible character provided by the isoidide diester derivative. Solvent-borne coatings were prepared by cross-linking the sugar-based polyester polyols with polyisocyanates. The increased rigidity of the obtained sugar-based polyester polyols led to an enhancement in hardness of the resulting coatings.

Side-chain liquid crystalline polyesters for optical information storage

DEFF Research Database (Denmark)

Ramanujam, P.S.; Holme, Christian; Hvilsted, Søren

1996-01-01

and holographic storage in one particular polyester are described in detail and polarized Fourier transform infrared spectroscopic data complementing the optical data are presented. Optical and atomic force microscope investigations point to a laser-induced aggregation as responsible for permanent optical storage.......Azobenzene side-chain liquid crystalline polyester structures suitable for permanent optical storage are described. The synthesis and characterization of the polyesters together with differential scanning calorimetry and X-ray investigations are discussed. Optical anisotropic investigations...

Aliphatic polyesters for medical imaging and theranostic applications.

Science.gov (United States)

Nottelet, Benjamin; Darcos, Vincent; Coudane, Jean

2015-11-01

Medical imaging is a cornerstone of modern medicine. In that context the development of innovative imaging systems combining biomaterials and contrast agents (CAs)/imaging probes (IPs) for improved diagnostic and theranostic applications focuses intense research efforts. In particular, the classical aliphatic (co)polyesters poly(lactide) (PLA), poly(lactide-co-glycolide) (PLGA) and poly(ɛ-caprolactone) (PCL), attract much attention due to their long track record in the medical field. This review aims therefore at providing a state-of-the-art of polyester-based imaging systems. In a first section a rapid description of the various imaging modalities, including magnetic resonance imaging (MRI), optical imaging, computed tomography (CT), ultrasound (US) and radionuclide imaging (SPECT, PET) will be given. Then, the two main strategies used to combine the CAs/IPs and the polyesters will be discussed. In more detail we will first present the strategies relying on CAs/IPs encapsulation in nanoparticles, micelles, dendrimers or capsules. We will then present chemical modifications of polyesters backbones and/or polyester surfaces to yield macromolecular imaging agents. Finally, opportunities offered by these innovative systems will be illustrated with some recent examples in the fields of cell labeling, diagnostic or theranostic applications and medical devices. Copyright © 2015 Elsevier B.V. All rights reserved.

Polarisation-sensitive optical elements in azobenzene polyesters and peptides

DEFF Research Database (Denmark)

Ramanujam, P.S.; Dam-Hansen, Carsten; Berg, Rolf Henrik

2006-01-01

In this article, we describe fabrication of polarisation holographic optical elements in azobenzene polyesters. Both liquid crystalline and amorphous side-chain polyesters have been utilised. Diffractive optical elements such as lenses and gratings that are sensitive to the polarisation...... of the incident light have been fabricated with polarisation holography. Computer-generated optical elements and patterns have also been written with a single polarised laser beam. Recording of polarisation defects enabling easy visualisation is also shown to be feasible in azobenzene polyesters....

Carboxylated Polyurethanes Containing Hyperbranched Polyester Soft Segments

Directory of Open Access Journals (Sweden)

Žigon, M.

2006-09-01

Full Text Available hyperbranched polyester soft segments (HB PU with functional carboxylic groups in order to enable the preparation of stable HB PU dispersions. Carboxylated hyperbranched polyurethanes were synthesized using a hyperbranched polyester based on 2,2-bis(methylolpropionic acid of the fourth pseudo-generation (Boltorn H40 and hexamethylene (HDI or isophorone diisocyanate (IPDI. The reactivity of hyperbranched polyester with HDI was lower than expected, possibly due to the presence of less reactive hydroxyl groups in the linear repeat units. A gel was formed at mole ratios rNCO/OH = 1:2 or 1:4. The synthesis of HB PU was performed with partly esterified hyperbranched polyester with lowered hydroxyl functionality. The carboxyl groups were incorporated in the HB PU backbone by reaction of residual hydroxyl groups with cis-1,2-cyclohexanedicarboxylic anhydride. HB PU aqueous dispersions were stable at least for two months, although their films were brittle. The tensile strength and Young's modulus of blends of linear and HB PU decreased with increasing content of HB PU whereas elongation at break remained nearly constant, which was explained in terms of looser chain packing due to more open tree-like hyperbranched structures.

Novel side-chain liquid crystalline polyester architecture for reversible optical storage

DEFF Research Database (Denmark)

Hvilsted, Søren; Andruzzi, Fulvio; Kulinna, Chrisian

1995-01-01

New side-chain liquid crystalline polyesters have been prepared by melt transesterification of diphenyl tetradecanedioate and a series of mesogenic 2-[omega-[4-[(4-cyanophenyl)azo]phenoxyl] alkyl]-1,3-propanediols, where the alkyl spacer is hexa-, octa-, and decamethylene in turn. The polyesters...... have molecular masses in the range 5000-89 000. Solution C-13 NMR spectroscopy has been employed to identify carbons of polyester repeat units and of both types of end groups. Polyester phases and phase transitions have been investigated in detail by polarizing optical microscopy and differential...... scanning calorimetry for the hexamethylene spacer architecture with different molecular masses. Using FTIR polarization spectroscopy, the segmental orientation in unoriented polyester films induced by argon ion laser irradiation has been followed and an irradiation-dependent order parameter...

Air-drying paint compositions comprising carbohydrate-based polyesters and polyester preparation

NARCIS (Netherlands)

Oostveen, E.A.; Weijnen, J.; Haveren, van J.; Gillard, M.

2003-01-01

The invention relates to a polyester obtainable by transesterification or interesterification of:(i) a carbohydrate or an acyl ester thereof, (ii) an alkyl ester of a drying fatty acid, semi-drying fatty acid or mixture thereof; and (iii) an alkyl ester of a non aromatic polycarboxylic acid. The

Komposit Hibrid Polyester Berpenguat Serbuk Batang Dan Serat Sabut Kelapa

OpenAIRE

Lumintang, Romels C. A; Soenoko, Rudy; Wahyudi, Slamet

2011-01-01

Sawdust coconut trunks of palm trees and fiber coconut coir are two waste materials from the processing of coconuts and coconut tree trunks sawmill waste are plentiful materials can be utilized for producing composites using polyester resins. Both each properties materials as follow polyester resin: liquid in the open air conditions, sawdust coconut and coconut coir fiber properties is lightweight and fragile nature of the polyester adhesive used as a binder (binder) between fiber coconut coi...

Procedure for the fabrication of a cross-linked polyester material

International Nuclear Information System (INIS)

D'Alelio, G.F.

1972-01-01

The procedures are described for the production of a cross-linked polyester material by means of the irradiation of a radiosensitive polyester with a dose of over 0.5 megarad and under 8 megarads high energy, ionising radiation, corresponding to at least 100,000 ev. The polyester is of the telomerised diacrylpolyester type, and may be in a mixture containing about 1% of a coplymerisable aliphatic monomer, or about 30-90% of an unsaturated aliphatic alkyd resin. (JIW)

Biodegradation of films of low density polyethylene (LDPE, poly(hydroxibutyrate-co-valerate (PHBV, and LDPE/PHBV (70/30 blend with Paecilomyces variotii

Directory of Open Access Journals (Sweden)

Thayse Marques Passos

2015-02-01

Full Text Available The increased consumption of plastics in the world has been a subject of great concern and special attention by the scientific community. The aim is to promote development of materials that are biodegradable in a shorter time upon disposal in the environment. The most used synthetic plastics are difficult to biodegrade because they are made of long hydrocarbon chains, such as polyethylene (PE, polypropylene (PP, poly(vinyl chloride (PVC, which are hydrophobic and resistant to the action of microbial enzymes. The use of alternative materials (natural polyesters can minimize the harm to dumps and landfills upon their disposal, because they are susceptible to the action of microorganisms. In this study we evaluated the biodegradation/biodeterioration of PHBV (poly(3-hydroxybutyrate-co-hydroxyvalerate films, LDPE (low density polyethylene and the blend of LDPE/PHBV (70/30 by the fungus Paecilomyces variotii, using different methods: optical microscopy (OM, scanning electronic microscopy (SEM and Fourier Transform Infrared spectroscopy (FTIR.

Radiation flame proofing of polyester/cotton blends

International Nuclear Information System (INIS)

Liepins, R.; Surles, J.R.; Morosoff, N.; Stannett, V.T.; Barker, R.H.

1977-01-01

Methodology has been developed for the grafting of vinyl functional organobromide and organophosphorus compounds on polyester fibers and 50/50 PET/cotton fabric. Procedures were developed for localized grafting of vinyl bromide (VBr) and diethylvinylphosphonate (DEVP) upon PET fibers. Oxygen index was used to evaluate the effect of the location of VBr and DEVP within the filament upon their flame retardance efficiencies. For the various bromine homopolymer grafts the apparent thermal stability of the graft and its flame retardance efficiency may be related to the alpha aliphatic hydrogen to bromine ratio. Using results from the polyester studies, techniques were devised for the treatment of 50/50 polyester/ cotton fabrics. Both homopolymer and copolymer grafts were evaluated but the greatest degree of success was attained using mixtures of phosphorus and bromine containing monomers. The results of these studies will be reviewed and their implications for development as commercial textile treatments discussed. (author)

Highly Branched Bio-Based Unsaturated Polyesters by Enzymatic Polymerization

Directory of Open Access Journals (Sweden)

Hiep Dinh Nguyen

2016-10-01

Full Text Available A one-pot, enzyme-catalyzed bulk polymerization method for direct production of highly branched polyesters has been developed as an alternative to currently used industrial procedures. Bio-based feed components in the form of glycerol, pentaerythritol, azelaic acid, and tall oil fatty acid (TOFA were polymerized using an immobilized Candida antarctica lipase B (CALB and the potential for an enzymatic synthesis of alkyds was investigated. The developed method enables the use of both glycerol and also pentaerythritol (for the first time as the alcohol source and was found to be very robust. This allows simple variations in the molar mass and structure of the polyester without premature gelation, thus enabling easy tailoring of the branched polyester structure. The postpolymerization crosslinking of the polyesters illustrates their potential as binders in alkyds. The formed films had good UV stability, very high water contact angles of up to 141° and a glass transition temperature that could be controlled through the feed composition.

Immediate implant placement using a biodegradable barrier, polyhydroxybutyrate-hydroxyvalerate reinforced with polyglactin 910. An experimental study in dogs

DEFF Research Database (Denmark)

Gotfredsen, K; Nimb, L; Hjørting-Hansen, E

1994-01-01

The purpose of this study was to evaluate the use of a biodegradable membrane of polyhydroxybutyrate-hydroxyvalerate copolymer reinforced with polyglactin 910 fibers, as an occlusive barrier over implants placed into fresh extraction sockets. Ten dogs had the 3rd and 4th mandibular premolars...... extracted bilaterally. Each dog had 4 Astra Dental Implants placed directly into the fresh extraction sockets. The top of the fixtures was placed at the same level as the top of the buccal cortical bone. The two implants in the right side were covered with the hydrolyzable polyester material...

Synthesis and Properties of Some polyurethane/ Partially Aromatic Polyester Casting Samples

International Nuclear Information System (INIS)

Sadek, E.M.; Mazroua, A.M.; Emam, A.S.; Motawie, A.M.

2005-01-01

A series of partially aromatic terephthalate polyesters were synthesized by melt transesterification of dimethyl terephthalate with various types of aliphatic diol compounds in 1:1.1 molar ratio. Ethylene-, di-, tri-, tetra ethylene glycol and polyethylene glycol with different molecular weights 1000, 4000, 6000 as well as the prepared dihydroxy natural rubber were used. Another series of partially aromatic adipate and sebacate polyesters based on the prepared bisphenol A and its tetrabromo derivative were also synthesized by direct polycondensation esterification with adipic and sebacic acid. Polyurethane with NCO/OH ratio equal 4 was prepared from the reaction of 2,4 toluene diisocyanate with polyethylene glycol 1000. The prepared polyurethane was mixed with different weight percentages (2, 4, 6, 8, 10 or 12 % w/w) of the prepared partially aromatic polyesters to give polyurethane/polyester compositions. Mechanical and electrical properties as well as water and chemical resistance of the prepared film samples with thickness 3-4 mm were determined and compared with those of polyurethane film sample without polyester. The data indicate that 10 % w/w of the added partially aromatic polyester increases polyurethane tensile strength, improves its insulation properties and hydrolytic stability as well as its chemical resistance. Film samples based on bisphenol A impart excellent properties as compared with those based on aliphatic glycol species and dihydroxy natural rubber. Keywords: Partially aromatic polyesters, Dimethyl terephthalate, Glycols, Bisphenol A, Tetrabromo bisphenol A, Natural rubber, Adipic acid, Sebacic acid, Polyurethane, Casting

Process for the production of a dianhydrohexitol based polyester

NARCIS (Netherlands)

2008-01-01

Process for the production of a polyester by the polycondensation of a mixture comprising isoidide, and a dicarboxylic acid or dicarboxylic acid anhydride, wherein the reaction is performed in the melt of the monomers and wherein these monomers are not activated. The polyesters based on one or more

Bio-based liquid crystalline polyesters

Science.gov (United States)

Wilsens, Carolus; Rastogi, Sanjay; Dutch Collaboration

2013-03-01

The reported thin-film polymerization has been used as a screening method in order to find bio-based liquid crystalline polyesters with convenient melting temperatures for melt-processing purposes. An in depth study of the structural, morphological and chemical changes occurring during the ongoing polycondensation reactions of these polymers have been performed. Structural and conformational changes during polymerization for different compositions have been followed by time resolved X-ray and Infrared spectroscopy. In this study, bio-based monomers such as vanillic acid and 2,5-furandicarboxylic acid are successfully incorporated in liquid crystalline polyesters and it is shown that bio-based liquid crystalline polymers with high aromatic content and convenient processing temperatures can be synthesized. Special thanks to the Dutch Polymer Institute for financial support

Interior microelectrolysis oxidation of polyester wastewater and its treatment technology

Energy Technology Data Exchange (ETDEWEB)

Yang Xiaoyi, E-mail: yangxiaoyi@buaa.edu.cn [Department of Thermal Energy Engineering, BeiHang University, Beijing 100191 (China)

2009-09-30

This paper has investigated the effects of interior microelectrolysis pretreatment on polyester wastewater treatment and analyzed its mechanism on COD and surfactant removal. The efficiency of interior microelectrolysis is mainly influenced by solution pH, aeration and reaction time. Contaminants can be removed not only by redox reaction and flocculation in the result of ferrous and ferric hydroxides but also by electrophoresis under electric fields created by electron flow. pH confirms the chemical states of surfactants, Fe(II)/Fe(III) ratio and the redox potential, and thus influences the effects of electrophoresis, flocculation and redox action on contaminant removal. Anaerobic and aerobic batch tests were performed to study the degradation of polyester wastewater. The results imply that interior microelectrolysis and anaerobic pretreatment are lacking of effectiveness if applied individually in treating polyester wastewater in spite of their individual advantages. The interior microelectrolysis-anaerobic-aerobic process was investigated to treat polyester wastewater with comparison with interior microelectrolysis-aerobic process and anaerobic-aerobic process. High COD removal efficiencies have been gotten by the combination of interior microelectrolysis with anaerobic technology and aerobic technology. The results also imply that only biological treatment was less effective in polyester wastewater treatment.

Interior microelectrolysis oxidation of polyester wastewater and its treatment technology

International Nuclear Information System (INIS)

Yang Xiaoyi

2009-01-01

This paper has investigated the effects of interior microelectrolysis pretreatment on polyester wastewater treatment and analyzed its mechanism on COD and surfactant removal. The efficiency of interior microelectrolysis is mainly influenced by solution pH, aeration and reaction time. Contaminants can be removed not only by redox reaction and flocculation in the result of ferrous and ferric hydroxides but also by electrophoresis under electric fields created by electron flow. pH confirms the chemical states of surfactants, Fe(II)/Fe(III) ratio and the redox potential, and thus influences the effects of electrophoresis, flocculation and redox action on contaminant removal. Anaerobic and aerobic batch tests were performed to study the degradation of polyester wastewater. The results imply that interior microelectrolysis and anaerobic pretreatment are lacking of effectiveness if applied individually in treating polyester wastewater in spite of their individual advantages. The interior microelectrolysis-anaerobic-aerobic process was investigated to treat polyester wastewater with comparison with interior microelectrolysis-aerobic process and anaerobic-aerobic process. High COD removal efficiencies have been gotten by the combination of interior microelectrolysis with anaerobic technology and aerobic technology. The results also imply that only biological treatment was less effective in polyester wastewater treatment.

Interior microelectrolysis oxidation of polyester wastewater and its treatment technology.

Science.gov (United States)

Yang, Xiaoyi

2009-09-30

This paper has investigated the effects of interior microelectrolysis pretreatment on polyester wastewater treatment and analyzed its mechanism on COD and surfactant removal. The efficiency of interior microelectrolysis is mainly influenced by solution pH, aeration and reaction time. Contaminants can be removed not only by redox reaction and flocculation in the result of ferrous and ferric hydroxides but also by electrophoresis under electric fields created by electron flow. pH confirms the chemical states of surfactants, Fe(II)/Fe(III) ratio and the redox potential, and thus influences the effects of electrophoresis, flocculation and redox action on contaminant removal. Anaerobic and aerobic batch tests were performed to study the degradation of polyester wastewater. The results imply that interior microelectrolysis and anaerobic pretreatment are lacking of effectiveness if applied individually in treating polyester wastewater in spite of their individual advantages. The interior microelectrolysis-anaerobic-aerobic process was investigated to treat polyester wastewater with comparison with interior microelectrolysis-aerobic process and anaerobic-aerobic process. High COD removal efficiencies have been gotten by the combination of interior microelectrolysis with anaerobic technology and aerobic technology. The results also imply that only biological treatment was less effective in polyester wastewater treatment.

Wettability and Impact Performance of Wood Veneer/Polyester Composites

Directory of Open Access Journals (Sweden)

Shayesteh Haghdan

2015-07-01

Full Text Available Fiber-reinforced thermosetting composites have been of interest since the 1940s due to their ease of use in processing, fast curing times, and high specific stiffness and strength. While the use of plant fibers in a polyester matrix has been thoroughly studied, only limited information is available regarding using wood as reinforcement. In this study, composites of thin wood veneer and a polyester matrix were made and the difficulties in the lamination and curing processes were investigated. Sheets of Douglas fir, maple, and oak veneers using a catalyzed polyester resin were assembled as unidirectional, balanced, and unbalanced cross-ply laminates. These were compared to control specimens using glass fiber as reinforcement. The impact properties of the samples, with respect to the laminate thicknesses, were characterized using a drop-weight impact tester. The wettability and surface roughness of unsanded and sanded wood veneers were also investigated. Results showed that Douglas fir cross-ply laminates had an impact energy equivalent to glass fiber laminates, making them an interesting alternative to synthetic fiber composites. Wood/polyester laminates absorbed a considerable amount of energy through a higher number of fracture modes. The balanced lay-up limited twisting of the wood/polyester composites. The lowest contact angle and highest wettability were observed in unsanded Douglas fir veneers.

Polyester polymer concrete overlay.

Science.gov (United States)

2013-01-01

Polyester polymer concrete (PPC) was used in a trial application on a section of pavement that suffers from extensive studded tire wear. The purpose of the trial section is to determine if PPC is a possible repair strategy for this type of pavement d...

Assessment of the radiation resistance of some aromatic polyesters

International Nuclear Information System (INIS)

Choi, E.J.; Hill, D.J.T.; Kim, K.Y.

1998-01-01

Full text: For many applications, polyesters have more useful properties than vinyl polymers, and they can be degraded to their monomer components and recycled. In addition, aromatic polyesters are known to display a resistance to high temperatures and high-energy ionizing radiation. Recently, we have reported the γ-radiolysis for some aromatic polyesters at low radiation dose; The G-values of radical formation at 77 K were determined to be in the range 0.38∼0.46 for the polyesters of bisphenol A with fluorine substitution at isopropylidene units and in the range 0.71∼1.18 for the polyesters of halogenated bisphenol A with decamethylene segments. While the radiation sensitivities of the latter polymers were dependent on the position and content of halogen substitution, those of the former polymers were slightly dependent on these factors as assessed by the G-values at 77 K. We also have studied the radiolysis of the commercial aromatic polyesters (UP) and polycarbonate (PC). UP has been found to be more radiation stable than PC with respect to the total yield of radicals formed. The G-values for radical formation at 77K was determined to be 0.31 and 0.5 for UP and PC, respectively. In this work, we have prepared poly(ethylene-, butylene- or decalene-terephthalate)s (PET, PBT or PDT) and poly(ethylene-, buthylene- or decalene-2,6-naphthalenedicarboxylate)s (PEN, PBN or PDN) by standard melt polymerization methods, and have examined their γ-radiolysis at 77 K or room temperature, and in vacuum or air, through the applications of ESR spectroscopy and thermal analysis. Inherent viscosities of the polyesters used for the radiation studies were in the range of 0.16∼0.69 dL/g. The values of G(R) indicates that PEN-related polymers have more radiation stable than PET-related polymers and the E, B and D order is one of decreasing stability as one might expect. The significant decrease in the G(R)-values of the polyester being in the range of 0.1∼0.41 at 77 K by

Synthesis and degradation kinetics of a novel polyester containing bithiazole rings

Energy Technology Data Exchange (ETDEWEB)

He, W., E-mail: hwdut2003@yahoo.com [Research Center of Plastic Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); State Key Laboratory of Robotics (China); Department of Chemistry, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Jiang, Y.Y. [Research Center of Plastic Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); State Key Laboratory of Robotics (China); Luyt, A.S. [Department of Chemistry, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Ocaya, R.O. [Department of Physics, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866 (South Africa); Ge, T.J. [Research Center of Plastic Engineering, Shenyang University of Chemical Technology, Shenyang 110142 (China); State Key Laboratory of Robotics (China)

2011-10-20

Highlights: {yields} A novel Schiff base type polyester was synthesized and characterized by FTIR spectroscopy, elemental analysis, and X-ray diffraction spectroscopy. {yields} Thermal degradation of the polyester in nitrogen has been studied at several heating rates by thermogravimetric analysis. {yields} The activation energies were calculated by different methods. And the possible conversation function was estimated. {yields} The life time estimates for the polyester can be determined and the results demonstrate that the polymer possesses good thermal resistance. - Abstract: A novel Schiff base type polyester containing 2,2'-diamino-4,4'-bithiazole (DABT) was prepared by low-temperature interface polycondensation of 1,4-benzenedicarbonyl dichloride with 4,4'-(4,4'-bithiazole-2,2'-diylbis(imine-2,1-diyl) diphenol (BDDP), which is derived from a 2,2'-diamino-4,4'-bithiazole (DABT) Schiff base reacted with a 4-hydroxybenzaldehyde monomer. The newly generated polyester was characterized by FTIR spectroscopy, elemental analysis, and X-ray diffraction spectroscopy. The thermal decomposition was investigated in nitrogen atmosphere using thermogravimetric analysis. The activation energies of the decomposition step of the polyester were calculated through the isoconversional methods of Kissinger-Akahira-Sunose (K-A-S) and the iterative equation. In order to estimate the reaction model that best describes the experimental data, the use of an empirical kinetic equation based on that proposed by Sestak-Berggren was investigated here. On the basis of the kinetic data, the life time estimates for the polyester generated from the weight loss of 5%, 10%, and 15% were also constructed.

Biobased functional polyesters for coating applications: Synthesis, characterization and application

NARCIS (Netherlands)

Noordover, B.A.J.; Duchateau, R.; Koning, C.E.; Benthem, van R.A.T.M.; Ming, W.; Haveren, van J.; Es, van D.S.

2007-01-01

Thermosetting coating systems contain polyesters as binders. A crucial property of these polymers is their functionality. During coating application, the polyesters are cross-linked in situ, which means that each polymer chain needs a sufficient no. of reactive end-groups. Renewable monomers are

Physico-chemical studies of gamma-irradiated polyester. Impregnated cement mortar composite

International Nuclear Information System (INIS)

Ismail, M.R.; Afifi, M.S.

1998-01-01

The effect of impregnation time on the physico-chemical and mechanical properties of polyester-cement mortar composite has been investigated. The samples were soaked in unsaturated polyester resin containing 40% styrene monomer at impregnation times ranging from 1-15 hours and then exposed to 50 kGy of γ-irradiation. The effects on polymer loading, compressive strength, apparent porosity, and water absorption in addition to IR spectra and TGA of the samples were studied. It was found that, the polymer loading and compressive strength increase with the increased of soaking time up to 4 hours and there is no significant improvement of the polymer loading and strength. Whereas, the apparent porosity and water absorption behave in an opposite direction. These are attributed to the presence of polymer in the pores of the samples. IR spectra showed that, new bands appeared as result of the reaction between polyester and set cement. TGA showed that, the polyester cement composite has higher thermal stability as a compared to irradiated polyester. (author)

Oleic Acid Based Polyesters of Trimethylolpropane and Pentaerythritol for Bio lubricant Application

International Nuclear Information System (INIS)

Hamizah Ammarah Mahmud; Nadia Salih; Jumat Salimon

2015-01-01

The production of polyesters based on oleic acid and trimethylolpropane (TMP) or pentaerythritol (PE) as potential bio lubricant were carried out. The esterification processes between oleic acid with TMP or PE were carried out using sulfuric acid as a catalyst. The esterification process produced high yield between 92 %-94 % w/w respectively. The formation of polyesters was confirmed using gas chromatography (GC-FID), Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). The polyesters were analyzed for basic lubrication physicochemical properties. The results showed that polyesters of both TMP and PE having high viscosity index between 200-309, good pour points ranging from -42 to -59 degree Celsius and high flash points of 280 - 300 degree Celsius respectively. The polyesters also showed good thermal oxidative stability with TGA onset temperatures above 180 degree Celsius. In general both products are plausible to be used as bio lubricant for industrial application. (author)

Study on the Antimicrobial Properties of Citrate-Based Biodegradable Polymers

Directory of Open Access Journals (Sweden)

Lee-Chun eSu

2014-07-01

Full Text Available Citrate-based polymers possess unique advantages for various biomedical applications since citric acid is a natural metabolism product, which is biocompatible and antimicrobial. In polymer synthesis, citric acid also provides multiple functional groups to control the crosslinking of polymers and active binding sites for further conjugation of biomolecules. Our group recently developed a number of citrate-based polymers for various biomedical applications by taking advantage of their controllable chemical, mechanical, and biological characteristics. In this study, various citric acid derived biodegradable polymers were synthesized and investigated for their physicochemical and antimicrobial properties. Results indicate that citric acid derived polymers reduced bacterial proliferation to different degrees based on their chemical composition. Among the studied polymers, poly(octamethylene citrate (POC showed approximately 70-80% suppression to microbe proliferation, owing to its relatively higher ratio of citric acid contents. Crosslinked urethane-doped polyester elastomers (CUPEs and biodegradable photoluminescent polymers (BPLPs also exhibited significant bacteria reduction of ~20% and ~50% for Staphylococcus aureus and Escherichia coli, respectively. Thus, the intrinsic antibacterial properties in citrate-based polymers enable them to inhibit bacteria growth without incorporation of antibiotics, silver nanoparticles, and other traditional bacteria-killing agents suggesting that they are unique beneficial materials for wound dressing, tissue engineering, and other potential medical applications where antimicrobial property is desired.

Mass spectrometry for the elucidation of the subtle molecular structure of biodegradable polymers and their degradation products.

Science.gov (United States)

Kowalczuk, Marek; Adamus, Grażyna

2016-01-01

Contemporary reports by Polish authors on the application of mass spectrometric methods for the elucidation of the subtle molecular structure of biodegradable polymers and their degradation products will be presented. Special emphasis will be given to natural aliphatic (co)polyesters (PHA) and their synthetic analogues, formed through anionic ring-opening polymerization (ROP) of β-substituted β-lactones. Moreover, the application of MS techniques for the evaluation of the structure of biodegradable polymers obtained in ionic and coordination polymerization of cyclic ethers and esters as well as products of step-growth polymerization, in which bifunctional or multifunctional monomers react to form oligomers and eventually long chain polymers, will be discussed. Furthermore, the application of modern MS techniques for the assessment of polymer degradation products, frequently bearing characteristic end groups that can be revealed and differentiated by MS, will be discussed within the context of specific degradation pathways. Finally, recent Polish accomplishments in the area of mass spectrometry will be outlined. © 2015 Wiley Periodicals, Inc.

Life-cycle assessment of textiles manufacture of polyester shirt (VB)

DEFF Research Database (Denmark)

Othman, Samer; Peter, Oduro Justice; Hassan, Osama

1998-01-01

According to the EDIP (Environmental Design of Industrial Products), It is made possible to perform resource and environmental profile analysis of the 100% polyester shirt. In order to understand the true life-cycle consequences, life-cycle analysis of a typical 100% polyester shirt was carried out...

Corrosion Protection Performance of Polyester-Melamine Coating with Natural Wood Fiber Using EIS Analysis

Energy Technology Data Exchange (ETDEWEB)

Shin, PyongHwa; Shon, MinYoung [Pukyong National University, Busan (Korea, Republic of); Jo, DuHwan [POSCO, Gwangyang (Korea, Republic of)

2016-04-15

In the present study, polyester-melamine coating systems with natural wood fiber (NWF) were prepared and the effects of NWF on the corrosion protectiveness of the polyester-melamine coating were examined using EIS analysis. From the results, higher average surface roughness was observed with increase of NWF content. Water diffusivity and water uptake into the polyester-melamine coatings with NWF were much higher than that into the pure polyester-melamine coating. The decrease in the impedance modulus |Z| was associated with the localized corrosion on carbon steel, confirming that corrosion protection of the polyester-melamine coatings with NWF well agrees with its water transport behavior.

Modification in the thermo mechanical behavior of biodegradable polyesters submitted to gamma radiation

International Nuclear Information System (INIS)

Mega, Veronica I; Fernandez, Victor; Eisenberg, Patricia; Hermida, Elida B

2006-01-01

The biopolymers poly(3- polyhydroxy butyrate) (PHB), poly(3-hydroxy butyrate-co-3-hydroxyvalerate) (PHBV) and their mixtures with other biodegradables like polycaprolactone (PCL) are materials that can be used in the production of food packaging and in bioabsorbable medical applications because of their good processability, suitable mechanical properties and complete degradation in different environments. Radiation γ is an appropriate method for the sterilization of food packaging. It offers good storage stability and high microbiological safety. This work proposes to study the effect of radiation γ on the mechanical and thermal properties of sheets of PHB, PHBV and of a PHB-based commercial biodegradable mixture. The samples standardized for traction tests were irradiated in air, at a constant dosage rate of 10 kGy/h. The range of absorbed doses was from 10 to 179 kGy. The possible structural changes were evaluated by attenuated total reflection infrared spectroscopy. The thermal properties were determined by differential scanning calorimetry (DSC) and the mechanical properties were measured with a universal test machine. The ruling mechanism during the gamma irradiation of Biocycle 1000 (PHB), 1400-2 (PHB-PCL) and PHBV is chain scission. The decreased vitreous transition melting and crytallization temperatures of PHB and PHBV after increasing the dosage, are evidence of the reduction in average molecular weight due to this mechanism. A similar effect was observed in the mechanical properties of irradiated PHBV, Biocycle 1000 and 1400-2: decreased resistance to traction and in the percentage of elongation to fracture, while the tensile module remains almost constant. The tenacity of the Biocycle 1000 is reduced more than that for the PHBV, which is less crystalline; showing that the damage occurs mostly in the crystalline region. This behavior is repeated in the Biocycle 1400-2. For the doses used in food irradiation or in sterilization of food packaging (≤ 20

Obtaining polyester from glycerin for synthesis of polyurethanes

International Nuclear Information System (INIS)

Breves, Rodolfo A.; Ghesti, Grace F.; Sales, Maria J.A.

2014-01-01

The use of renewable resources has been increasing, due to the development of materials that have viable applications that are environmentally friendly. In this paper, a polyester was synthesized from glycerin, with the addition of adipic acid in a molar ratio of 1: 1.5, with dilauryl tin catalyst, which was added in proportions of 1 to 3% obtained PUs from castor oil (Ricinus communis) and MDI (diphenyl methane diisocyanate). The materials were characterized by infrared spectroscopy (FTIR), nuclear magnetic resonance "1H NMR, thermogravimetry (TG) and derivative thermogravimetry (DTG). The reaction for obtaining the polyester was confirmed by FTIR, the absorption band between 1708-1730 cm"-"1 and "1H NMR, in the region 1.4 to 1.8 ppm and 2.2 to 2.6 ppm. The thermal decomposition of polyester occurred with temperature above 300 ° C. PUs showed similar thermal stability. (author)

Biodegradable, elastomeric coatings with controlled anti-proliferative agent release for magnesium-based cardiovascular stents.

Science.gov (United States)

Gu, Xinzhu; Mao, Zhongwei; Ye, Sang-Ho; Koo, Youngmi; Yun, Yeoheung; Tiasha, Tarannum R; Shanov, Vesselin; Wagner, William R

2016-08-01

Vascular stent design continues to evolve to further improve the efficacy and minimize the risks associated with these devices. Drug-eluting coatings have been widely adopted and, more recently, biodegradable stents have been the focus of extensive evaluation. In this report, biodegradable elastomeric polyurethanes were synthesized and applied as drug-eluting coatings for a relatively new class of degradable vascular stents based on Mg. The dynamic degradation behavior, hemocompatibility and drug release were investigated for poly(carbonate urethane) urea (PCUU) and poly(ester urethane) urea (PEUU) coated magnesium alloy (AZ31) stents. Poly(lactic-co-glycolic acid) (PLGA) coated and bare stents were employed as control groups. The PCUU coating effectively slowed the Mg alloy corrosion in dynamic degradation testing compared to PEUU-coated, PLGA-coated and bare Mg alloy stents. This was confirmed by electron microscopy, energy-dispersive x-ray spectroscopy and magnesium ion release experiments. PCUU-coating of AZ31 was also associated with significantly reduced platelet adhesion in acute blood contact testing. Rat vascular smooth muscle cell (rSMC) proliferation was successfully inhibited when paclitaxel was released from pre-loaded PCUU coatings. The corrosion retardation, low thrombogenicity, drug loading capacity, and high elasticity make PCUU an attractive option for drug eluting coating on biodegradable metallic cardiovascular stents. Copyright © 2016 Elsevier B.V. All rights reserved.

Radiation cured polyester compositions containing metal-properties

Science.gov (United States)

Szalińska, H.; Pietrzak, M.; Gonerski, A.

The subject of the studies was unsaturated polyester resin, Polimal-109 and its compositions containing acrylates of: sodium, potassium, calcium, magnesium, barium, manganese, iron, cobalt, copper and acrylic acid. Polyester resin modified with acrylic acid salts was cured with 60Co gamma radiation. Measurements of Vicat softening temperature, water absorption, creep current resistance, volume and surface resistivity, the tangent of dielectric loss angle and permittivity of radiation cured compositions were carried out. The results of the studies presented testify to the fact that the properties of cross-linked polymers alter after ionogenic compounds have been introduced into them.

Radiation cured polyester compositions containing metal-properties

International Nuclear Information System (INIS)

Szalinska, H.; Pietrzak, M.; Gonerski, A.

1987-01-01

The subject of the studies was unsaturated polyester resin, Polimal-109 and its compositions containing acrylates of: sodium, potassium, calcium, magnesium, barium, manganese, iron, cobalt, copper and acrylic acid. Polyester resin modified with acrylic acid salts was cured with 60 Co gamma radiation. Measurements of Vicat softening temperature, water absorption, creep current resistance, volume and surface resistivity, the tangent of dielectric loss angle and permittivity of radiation cured compositions were carried out. The results of the studies presented testify to the fact that the properties of cross-linked polymers alter after ionogenic compounds have been introduced into them. (author)

Sustainable coatings from bio-based, enzymatically synthesized polyesters with enhanced functionalities

NARCIS (Netherlands)

Gustini, L.; Lavilla, C.; Finzel, L.; Noordover, B.A.J.; Hendrix, M.M.R.M.; Koning, C.E.

2016-01-01

Bio-based sorbitol-containing polyester polyols were synthesized via enzymatic polycondensation. The selectivity of the biocatalyst for primary vs. secondary hydroxyl groups allowed for the preparation of close to linear renewable polyester polyols with enhanced hydroxyl functionalities, both as

Reactive distillation: an attractive alternative for the synthesis of unsaturated polyester

NARCIS (Netherlands)

Shah, M.R.; Zondervan, E.; Oudshoorn, M.L.; Haan, de A.B.

2011-01-01

Unsaturated polyester is traditionally produced in a batch wise operating reaction vessel connected to a distillation unit. An attractive alternative for the synthesis of unsaturated polyester is a reactive distillation. To value such alternative synthesis route reliable process models need to be

Phase diagrams in blends of poly(3-hydroxybutyric acid with various aliphatic polyesters

Directory of Open Access Journals (Sweden)

2011-07-01

Full Text Available Phase behavior with immiscibility, miscibility, crystalline morphology, and kinetic analysis in blends of poly(3-hydroxybutyric acid (PHB with aliphatic polyesters such as poly(butylene adipate (PBA, poly(ethylene adipate (PEA, poly(trimethylene adipate (PTA, or poly(ethylene succinate (PESu, respectively, were explored mainly using differential scanning calorimeter (DSC and polarized-light optical microscopy (POM. Immiscibility phase behavior with reversible upper-critical-solution-temperature (UCST is common in the PHB/polyester blends. The polyester/polyester blend of PHB/PTA is partially miscible with no UCST in melt and amorphous glassy states within a composition range of PTA less than 50 wt%. The miscible crystalline/crystalline blend exhibits ring-banded spherulites at Tc = 50~100°C, with inter-ring spacing dependent on Tc. All immiscible or partially miscible PHB/polyester blends, by contrast, exhibit disrupted ringbanded spherulites or discrete spherical phase domains upon cooling from UCST to crystallization. The blends of PHB with all other aliphatic polyesters, such as PESu, PEA, PBA, etc. are only partially miscible or immiscible with an upper critical solution temperature (UCST at 180~221°C depending on blend composition. UCST with reversibility was verified.

Thermal Degradation Mechanism of a Thermostable Polyester Stabilized with an Open-Cage Oligomeric Silsesquioxane

Directory of Open Access Journals (Sweden)

Yolanda Bautista

2017-12-01

Full Text Available A polyester composite was prepared through the polymerization of an unsaturated ester resin with styrene and an open-cage oligomeric silsesquioxane with methacrylate groups. The effect of the open-cage oligomeric silsesquioxane on the thermal stability of the thermostable polyester was studied using both thermogravimetric analysis and differential thermal analysis. The results showed that the methacryl oligomeric silsesquioxane improved the thermal stability of the polyester. The decomposition mechanism of the polyester/oligomer silsesquioxane composite was proposed by Fourier transform infrared spectroscopy (FTIR analysis of the volatiles.

76 FR 11268 - Certain Polyester Staple Fiber From Korea and Taiwan

Science.gov (United States)

2011-03-01

... Polyester Staple Fiber From Korea and Taiwan AGENCY: United States International Trade Commission. ACTION... Korea and Taiwan. SUMMARY: The Commission hereby gives notice that it has instituted reviews pursuant to... the antidumping duty orders on certain polyester staple fiber from Korea and Taiwan would be likely to...

Synthesis, characterization and ESR study of polyesters containing isomeric naphthylene units by gamma irradiation

International Nuclear Information System (INIS)

Choi, B.K.; Hill, D.J.T.; Choi, E.J.; Ahn, H.K.

1998-01-01

Full text: Aromatic polyesters containing naphthalene groups have interesting properties because the geometry of the naphthalene group can provide many of the structural features for the polymer chain. In this study we synthesized six polyesters from 4,4 ' - (hexafluoroisopropyl-idene)bis(benzoic acid) and isomeric naphthylene-diols. An ESR study of the radicals formed on gamma radiolysis of the polyesters has been undertaken to investigate their relative radiation sensitivities. The structures of the polyesters were characterized by means of IR spectroscopy. Inherent viscosities were measured in the range of 0.11 - 0.46 dL/g. Thermal properties of polyesters were determined by DSC and TGA thermograms, respectively. All polyesters were irradiated in an AECL Gamma cell with a dose rate of approximately 6.7kGy h -1 to doses in the range of 0 - 15kGy at 77K and 300K, respectively. In order to identify other radicals present at 77K, annealing studies were utilized by taking advantage of the different reactivities of these radicals

Rewritable azobenzene polyester for polarization holographic data storage

DEFF Research Database (Denmark)

Kerekes, A; Sajti, Sz.; Loerincz, Emoeke

2000-01-01

Optical storage properties of thin azobenzene side-chain polyester films were examined by polarization holographic measurements. The new amorphous polyester film is the candidate material for the purpose of rewritable holographic memory system. Temporal formation of anisotropic and topographic...... gratings was studied in case of films with and without a hard protective layer. We showed that the dominant contribution to the diffraction efficiency comes from the anisotropy in case of expositions below 1 sec even for high incident intensity. The usage of the same wavelength for writing, reading...

The biomechanical evaluation of polyester as a tension band for the internal fixation of patellar fractures.

LENUS (Irish Health Repository)

McGreal, G

2012-02-03

We use a braided polyester suture in place of cerclage wire in tension band fixations. The objective of this study was to test the biomechanical properties of this technique. Sixteen cadaveric patellae were fractured and repaired by modified tension band fixation. Eight were fixed using eighteen gauge stainless steel wire as a tension band and eight using braided polyester. All specimens were subjected to tensile testing. Polyester was 75.0% as strong as wire. For dynamic testing, the patellae of seven cadaveric knees were fractured and then fixed with polyester tension bands. These were mounted in a device capable of extending the knees from 90 degrees to neutral against an applied force. None of the fixations failed. Three of the specimens fixed using 18 gauge stainless steel wire were compared with three fixed using polyester over 2000 cycles of knee flexion and extension. Polyester performed as well as wire. We conclude that polyester is an acceptable alternative to wire in tension band fixation.

Study on the improvement of hydrophilic character on polyvinylalcohol treated polyester fabric

Directory of Open Access Journals (Sweden)

S. Pitchai

2014-12-01

Full Text Available Polyester fabric was treated with polyvinyl alcohol in alkaline medium. The moisture regain, water retention and wettability of the PVA treated polyester fabric were tested. The PVA treated PET fabric was dyed with disperse dye. The presence of PVA in the treated PET fabric was assessed by spot test. The treated fabric was also characterized by scanning electron microscope, FTIR and differential scanning calorimetry. The PVA treated polyester fabric showed improved hydrophilic character over intact and sodium hydroxide treated PET fabrics.

Characterizing the sorption of polybrominated diphenyl ethers (PBDEs) to cotton and polyester fabrics under controlled conditions

Energy Technology Data Exchange (ETDEWEB)

Saini, Amandeep [Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military trail, Toronto, ON M1C 1A4 (Canada); Rauert, Cassandra [School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT (United Kingdom); Simpson, Myrna J. [Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military trail, Toronto, ON M1C 1A4 (Canada); Harrad, Stuart [School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT (United Kingdom); Diamond, Miriam L., E-mail: miriam.diamond@utoronto.ca [Department of Earth Sciences, 22 Russell Street, University of Toronto, Toronto, ON M5S 3B1 (Canada); Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military trail, Toronto, ON M1C 1A4 (Canada)

2016-09-01

Cotton and polyester, physically and chemically different fabrics, were characterized for sorption of gas-phase polybrominated diphenyl ethers (PBDEs). Scanning electron microscopic (SEM) images and BET specific surface area (BET-SSA) analysis showed cotton's high microsurface area; NMR analysis showed richness of hexose- and aromatic-carbon in cotton and polyester, respectively. Cotton and polyester sorbed similar concentrations of gas-phase PBDEs in chamber studies, when normalized to planar surface area. However, polyester concentrations were 20–50 times greater than cotton when normalized to BET-SSA, greater than the 10 times difference in BET-SSA. The difference in sorption between cotton and polyester is hypothesized to be due to ‘dilution’ due to cotton's large BET-SSA and/or greater affinity of PBDEs for aromatic-rich polyester. Similar fabric-air area normalized distribution coefficients (K'{sub D}, 10{sup 3} to 10{sup 4} m) for cotton and polyester support air-side controlled uptake under non-equilibrium conditions. K'{sub D} values imply that 1 m{sup 2} of cotton or polyester fabrics would sorb gas-phase PBDEs present in 10{sup 3} to 10{sup 4} m{sup 3} of equivalent air volume at room temperature over one week, assuming similar air flow conditions. Sorption of PBDEs to fabrics has implications for their fate indoors and human exposure. - Highlights: • Sorption of gas-phase PBDEs by cotton and polyester fabrics • Similar sorption to cotton and polyester per unit planar surface area • Greater sorption by polyester/BET-SSA; cotton's dilution or polyester’s affinity • 1 m{sup 2} fabric sorbs PBDEs in 10{sup 3} to 10{sup 4} m{sup 3} of equivalent air volume • Clothing likely a large indoor sink of PBDEs and influence human exposure.

PENGARUH PENGGUNAAN SERAT KULIT ROTAN SEBAGAI PENGUAT PADA KOMPOSIT POLIMER DENGAN MATRIKS POLYESTER YUKALAC 157 TERHADAP KEKUATAN TARIK DAN DAN TEKUK

Directory of Open Access Journals (Sweden)

Sarjito Jokosisworo

2012-02-01

Full Text Available This time, rattan bark fiber’s used in furniture industries and home industries because it is easy to get, cheap,not to be danger for our health, and it can lesson environment pollution (biodegradability; so, with exploit ascomposites lasing fibre, later, it can overcome the environment problem. The rattan bark development ascomposite material has already know, in view of the raw material of natural fibre (rattan available, Indonesiahas many raw material. From this case, this research conducted to get technical analysis of tensile strength andbending from rattan bark fibre composite that is using woven roving treatment of variation matting pattern onfibre direction 0º/90º and 45º angles as polyester resin matrix.The purpose of this research is: to identify the tensile strength and bending of composite of rattan bark fibrewhich influence fibre direction between 0º/90º and 45º angles. From the result of specimen trial is served intensile strength and bending, and compared with tensile strength and bending value which permitted by BKI (Biro Klasifikasi Indonesia as theory of standardization trial. On the research, the writer found composite thathave rattan bark fibre compared 0º/90º and 45º angle of fibre direction, the treatment of matting pattern fibre,volume fraction 42,8% matrix polyester and 57,2% rattan bark fibre to specimen of tensile strength trial,volume fraction 50% matrix polyester and 50% rattan bark fibre to specimen bending trials. Conducted handlay up method, from the result study found the price maximum of tensile strength has got by composite with0º/90º and 45º fibre direction and maximum bending has got by composite with 45º fibre direction.

The radiation chemistry of symmetric aliphatic polyesters

International Nuclear Information System (INIS)

Babanalbandi, A.; Hill, D.J.T.; Pomery, P.J.; Whittaker, A.K.

1996-01-01

Full text: Naturally occurring, symmetric polyesters, including polyglycolic acid, polylactic acid and polyhydroxybutyrate, have found biomedical applications in areas as diverse as the controlled release of pharmaceuticals and the manufacture of surgical sutures. As biomedical products, the materials require sterilization by high energy radiation. This has provided the motivation for the present work. D'Alelio et al. have reported that linear, asymmetric polyesters undergo scission on irradiation, but that branched polyesters containing a methyl group in the diol segments undergo crosslinking. However, for the symmetric polyhydroxybutyrate, Carswell-Pomerantz et al. have reported that only scission occurs on radiolysis, with the evolution of CO and CO 2 as a result of the loss of ester linkages. These workers also found that G(CO + CO 2 ) was approximately equal to G(S) for this polyester. By contrast, Collett et al. have reported that G(S) = 1.26 and G(X) = 0.53 for polylactic acid, which indicates that the polymer undergoes nett crosslinking on radiolysis to form a gel. They have also reported that poly(lactic-co-glycolic acid) should form a gel on radiolysis, since G(S) = 1.66 and G(X) = 0.65 for a 1:1 copolymer composition. In the present work the radiolysis of polylactic acid and poly(lactic-co-glycolic acid) have been reinvestigated in order to resolve the differences between the work of Collett et al. and that of Carswell-Pomerantz et al. In these studies, ESR has been used to study the radicals formed, GPC has been used to investigate scission and crosslinking, GC has been used to study the small molecule volatile products and NMR spectroscopy has been used to identify and measure the new chemical structures formed in the polymers

Gamma Irradiation Effect on Biodegradable Poly (Hydroxybutyrate) Studied by Positron Annihilation Technique

International Nuclear Information System (INIS)

Abdel-Hady, E.E.; Mohamed, S.S.

2010-01-01

-Bacterial polyesters have attracted much attention as biodegradable polymers. An ecofriendly alternative to this biodegradable material is poly-3-hydroxybutyrate (PHB) which has attracted industrial attention as an environmentally degradable plastic for a wide range of medical applications. Free volume holes in polymers play a crucial role in determining its physical properties. The Positron Annihilation Lifetime (PAL) technique has been established as a powerful probe for microstructures of polymers, in particular, angstrom-sized free volume holes. The PHB samples were irradiated using 60 Co source at room temperature with doss ranging from 5 to 300 kGy. The PAL spectra for all the samples have been measured at room temperature as a function of gamma-irradiation dose. The free volume hole size decreases with increasing the irradiation dose up to 25 kGy followed by slowly increases up to 200 kGy, then decreases at higher doses. On the other hand, the free volume content decreases with increasing the gamma-irradiation dose which is due to the increase of the degree of crystallinity. The variations in the free volume with the irradiation dose will be discussed in the frame of free volume model. A correlation between the macroscopic mechanical properties Hv and positron annihilation parameters has been done

Effect of hydroxyapatite on the biodegradation and biomechanical stability of polyester nanocomposites for orthopaedic applications.

Science.gov (United States)

Jayabalan, M; Shalumon, K T; Mitha, M K; Ganesan, K; Epple, M

2010-03-01

The effect of hydroxyapatite (HAP) on the performance of nanocomposites of an unsaturated polyester, i.e., hydroxy-terminated high molecular weight poly(proplyene fumarate) (HT-PPFhm), was investigated. A thermoset nanocomposite was prepared with nanoparticles of calcined HAP (<100 nm, rod-like shape, filler content 30 wt.%), HT-PPFhm and N-vinyl pyrrolidone, dibenzoyl peroxide and N,N-dimethyl aniline. Two more nanocomposites were prepared with precipitated HAP nanoparticles (<100 nm rod-like shape) and commercially available HAP nanoparticles (<200 nm spherical shape), respectively. Calcined HAP nanoparticles resulted in very good crosslinking in the resin matrix with high crosslinking density and interfacial bonding with the polymer, owing to the rod-like shape of the nanoparticles; this gave improved biomechanical strength and modulus and also controlled degradation of the nanocomposite for scaffold formation. The tissue compatibility and osteocompatibility of the nanocomposite containing calcined HAP nanoparticles was evaluated. The tissue compatibility was studied by intramuscular implantation in a rabbit animal model for 3 months as per ISO standard 10993/6. The in vivo femoral bone repair was also carried out in the rabbit animal model as per ISO standard 10993/6. The nanocomposite containing calcined HAP nanoparticles is both biocompatible and osteocompatible. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

76 FR 58040 - Certain Polyester Staple Fiber From Korea and Taiwan

Science.gov (United States)

2011-09-19

... Polyester Staple Fiber From Korea and Taiwan Determination On the basis of the record \\1\\ developed in the... antidumping duty orders on certain polyester staple fiber from Korea and Taiwan would be likely to lead to continuation or recurrence of material injury to an industry in the United States within a reasonably...

[Analysis of anatomical pieces preservation with polyester resin for human anatomy study].

Science.gov (United States)

de Oliveira, Ítalo Martins; Mindêllo, Marcela Maria Aguiar; Martins, Yasmin de Oliveira; da Silva Filho, Antônio Ribeiro

2013-01-01

To evaluate the use of polyester resin in preserving anatomical specimens for the study of human anatomy. We used 150 anatomical specimens, comprised of unfixed (fresh), fixed in 10% formalin and vascular casts of organs injected with vinyl acetate and polyester resin. The solution used consisted of polyester resin with the diluent styrene monomer and catalyst (peroxol). After embedding in this solution, models in transparent resin were obtained, allowing full observation of structures and conservation of the specimens used. upon evaluation of the specimens, we observed a high degree of transparency, which promoted a complete visualization of structures with perfect preservation of the anatomy. The average time for the completion of the embedding was 48 hours. Only 14 specimens (9.3%) were lost during the preparation. Polyester resin can be used for preserving anatomical specimens for teaching human anatomy in a practical, aesthetic and durable way.

Flame Retardance and Physical Properties of Novel Cured Blends of Unsaturated Polyester and Furan Resins

Directory of Open Access Journals (Sweden)

Baljinder Kaur Kandola

2015-02-01

Full Text Available Novel blends of two furan resins with an unsaturated polyester have been prepared and cured by parallel free radical (for the unsaturated polyester and acid-catalysed crosslinking (for the furan resin to give co-cured composite materials. Although these materials have inferior physical properties, such as low Tg and low storage modulus compared with those of unsaturated polyester and furan resins alone, they show markedly improved flame retardance compared with that of the normally highly flammable unsaturated polyester. This increased flame retardance arises from a condensed phase mechanism in which the furanic component forms a semi-protective char, reducing rates of thermal degradation and total heat release and heat of combustion. The blends also burn with reduced smoke output compared with that from unsaturated polyester alone.

Light-induced circular birefringence in cyanoazobenzene side-chain liquid-crystalline polyester films

DEFF Research Database (Denmark)

Naydenova, I; Nikolova, L; Ramanujam, P.S.

1999-01-01

We report the inducement of large circular birefringence (optical activity) in films of a cyanoazobenzene side-chain liquid-crystalline polyester on illumination with circularly polarized light. The polyester has no chiral groups and is initially isotropic. The induced optical rotation is up to 5...

Cellular internalization and transport of biodegradable polyester dendrimers on a model of the pulmonary epithelium and their formulation in pressurized metered-dose inhalers.

Science.gov (United States)

Heyder, Rodrigo S; Zhong, Qian; Bazito, Reinaldo C; da Rocha, Sandro R P

2017-03-30

The purpose of this study was to evaluate the effect of generation and surface PEGylation of degradable polyester-based dendrimers nanocarriers on their interactions with an in vitro model of the pulmonary epithelium as well as to assess the ability to formulate such carriers in propellant-based, portable oral-inhalation devices to determine their potential for local and systemic delivery of drugs to and through the lungs. Hydroxyl (-OH) terminated polyester dendrimers of generation 3 and 4 (G3, and G4) were synthesized using a divergent approach. G4 was surface-modified with PEG (1,000Da). All dendrimers and their building blocks were determined to be highly compatible with the model pulmonary epithelium, with toxicity profiles much more favorable than non-degradable polyamidoamine dendrimers (PAMAM). The transport of the species from the apical to basolateral side across polarized Calu-3 monolayers showed to be generation and surface-chemistry (PEGylation) dependent. The extent of the transport is modulated by their interaction with the polarized epithelium and their transient opening of the tight junctions. G3 was the one most efficiently internalized by the epithelium, and had a small impact on the integrity of the monolayer. On the other hand, the PEGylated G4 was the one least internalized by the polarized epithelium, and at the same time had a more pronounced transient impact on the cellular junctions, resulting in more efficient transport across the cell monolayer. PEGylation of the dendrimer surface played other roles as well. PEGylation modulated the degradation profile of the dendrimer, slowing the process in a step-wise fashion - first the PEG layer is shed and then the dendrimer starts degrading. PEGylation also helped increase the solvation of the nanocarriers by the hydrofluoroalkane propellant used in pressurized metered-dose inhalers, resulting in formulations with excellent dispersibility and aerosol quality (deep lung deposition of 88

Properties and performance of flax yarn/thermoplastic polyester composites

DEFF Research Database (Denmark)

Madsen, Bo; Mehmood, Shahid

2012-01-01

Aiming at demonstrating the potential of unidirectional natural fiber-reinforced thermoplastic composites in structural applications, textile flax yarn/thermoplastic polyester composites with variable fiber volume fractions have been manufactured by a filament-winding process followed by a vacuum......-assisted compression molding process. The microstructure of the composites shows that the flax fiber yarns are well impregnated by the polyester matrix, and this supports the measured low porosity content of the composites. The experimental tensile modulus and ultimate tensile stress of the composites in the axial...

Polyester textile functionalization through incorporation of pH/thermo-responsive microgels. Part II: polyester functionalization and characterization

NARCIS (Netherlands)

Glampedaki, P.; Calvimontes, A.; Dutschk, Victoria; Warmoeskerken, Marinus

2012-01-01

A new approach to functionalize the surface of polyester textiles is described in this study. Functionalization was achieved by incorporating pH/temperature-responsive polyelectrolyte microgels into the textile surface layer using UV irradiation. The aim of functionalization was to regulate

Polyester Polyols from Waste PET Bottles for Polyurethane Rigid Foams

OpenAIRE

Evtimova, Rozeta; Lozeva, Yordanka; Schmidt, Karl-Heinz; Wotzka, Michael; Wagner, Peter; Behrendt, Gerhard

2003-01-01

This paper describes a modified process to produce polyester polyols from PET wastes derived from the “bottle fraction residue” of the German Dual System (DSD) [11] employing a waste oligoester condensate of the polyesterification process with the addition of some glycols of longer chain and occasional modification with further dicarboxylic acids to produce polyester polyols of a broad range of properties which are further reacted to form polyurethane or polyisocyanurate rigid foams for insul...

New UV-curable acrylated polyester prepolymers from palm oil based products

International Nuclear Information System (INIS)

Mohd Azam Ali; Ooi, T.L.; Salmiah Ahmad; Umaru, S.I.; Mohd Ishak, Z.A.

1999-01-01

Acrylated polyester prepolymers (PEPP-1 and PEPP-2) were synthesized from palm oil and its products. UV-curing and characteristic properties of UV-cured films of synthesized polyester resins were studied. The characteristic properties studied include pendulum hardness, gel content, FT-IR analysis, tensile strength and elongation at break. The materials have good potential for the production of radiation curable coating applications

Composite Preparation of Wood Dust-Polyester-Coconut Choir Fiber Mixture for Particle Board

International Nuclear Information System (INIS)

Danu, Sugiarto; Darsono; Padmono; Betty, Angesti

2002-01-01

Experiment on the use of γ-ray of Co 60 radiation has been used for curing of composite which made of wood dust, unsaturated polyester resin and coconut coir mixture. Composite was prepared by mixing of wood dust, polyester and coconut coir at a various mixture composition. Concentration of polyesters were 50, 55 and 60 % by weight based on saw dust and polyester mixture. Irradiation was conducted using 27,6 kCi acti vity Co 60 at a dose rate of 5 kGy/hrs and dose of 8, 10 and 12 kGy. Composite was also prepared conventionally by using peroxide catalyst. Parameters observed were density, pencil hardness and compression strength Experimental results showed that optimum condition wus achieved at irradiation dose of 12 kGy, polyester concentration of 60 % and coconut coir fiber of 4 %. In this condition, the density, hardness and compression strength were 1,115 g/cm 3, 5 Hand 6,815 kN/cm2 respectively. Density, hardness of composite prepared by radiation were almost the same whereas the compression strength was higher than that of composite prepared by conventional method

Nuclear magnetic resonance structure investigations on crosslinked polyesters

International Nuclear Information System (INIS)

Grobelny, J.

1999-01-01

Styrene-crosslinked mixed polyesters derived from maleic anhydride, 2,2-di(4-hydroxypropoxyphenyl)propane, oligo(propylene oxide) and 1,2-propylene glycol were investigated by high-resolution solid-state 13 C NMR spectroscopy. The structural modifications accompanying crosslinking were characterized in terms of spin-lattice relaxation times as a function of unsaturated polyester composition. Copolymerization and crosslinking effects were individually evaluated and the latter effect was related to variations in crosslinking density associated with the chemical structure of the unsaturated prepolymer. As the crosslinking effect is suppressed, the mechanical properties undergo expected changes, e.g., impact strength is increased and modulus of elasticity in tension is decreased. (author)

The studies on waste biodegradation by Tenebrio molitor

Directory of Open Access Journals (Sweden)

Bożek Magdalena

2017-01-01

Full Text Available As cities are growing in size with a rise in the population, the amount of plastic waste generated is increasing and becoming unmanageable. The treatment and disposal of plastic waste is an urgent need of our present and future. It has been proved recently that mealworms, the larvae of Tenebrio molitor Linnaeus, are able eat styrofoam, a common polystyrene product. Polystyrene is one of the most widely used plastics, the scale of its production being several million tons per year. Tenebrio molitor is one of the largest pests found in stored-grain products. The insect is indigenous to Europe, but is currently cosmopolitan in distribution. The styrofoam is efficiently degraded in the larval gut by microorganisms. We have used the larvae of T. molitor to biodegrade three types of food packaging plastics: polystyrene (PS, polyvinyl chloride (PVC and polylactide (PLA. PVC is a thermoplastic made of 57% chlorine (derived from industrial grade salt and 43% carbon (derived predominantly from oil /gas via ethylene. It is the world's third-most widely produced synthetic plastic polymer, which is not biodegradable easily. On the other hand, PLA is an easily biodegradable and bioactive thermoplastic aliphatic polyester derived from corn and tapioca starch or sugarcane. Three groups of larvae were fed selected types of polymers as an only food, while a control population was fed on oatmeal. The mass loss, dry matter content and biochemical composition of mealworms were assessed in the performed laboratory experiments. The protein concentration in homogenates of the larvae was determined by the Bradford method. To determine the level of hydrolized carbohydrates we used anthrone method. The classical sulfo-phospho-vanillin assay (SPVA was used to quantitate total lipids in mealworms. The results allowed to compare the decomposition efficiency of selected polymer materials by mealworms and to recognize the mechanism of decomposition contributing to the future

Photoinduced Deformation of Azobenzene Polyester Films

DEFF Research Database (Denmark)

Bublitz, D.; Helgert, M.; Fleck, B.

2000-01-01

We investigate two types of azobenzene side-chain polyesters which have shown opposite behaviour in light-induced surface grating formation experiments. Thin films of these polymers prepared on a water surface undergo opposite changes of shape under the influence of polarized light. We propose...

Micro-thermal analysis of polyester coatings

NARCIS (Netherlands)

Fischer, H.R.

2010-01-01

The application and suitability of micro-thermal analysis to detect changes in the chemical and physical properties of coating due to ageing and especially photo-degradation is demonstrated using a model polyester coating based on neopentyl glycol isophthalic acid. The changes in chemical structure

Magnesium Coated Bioresorbable Phosphate Glass Fibres: Investigation of the Interface between Fibre and Polyester Matrices

Directory of Open Access Journals (Sweden)

Xiaoling Liu

2013-01-01

Full Text Available Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+ in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM. The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM and X-ray diffraction (XRD analysis, respectively. The roughness of the coatings was seen to increase from 40±1 nm to 80±1 nm. The mechanical properties (tensile strength and modulus of fibre with coatings decreased with increased magnesium coating thickness.

Tensile strength of woven yarn kenaf fiber reinforced polyester composites

OpenAIRE

A.E. Ismail; M.A. Che Abdul Aziz

2015-01-01

This paper presents the tensile strength of woven kenaf fiber reinforced polyester composites. The as-received yarn kenaf fiber is weaved and then aligned into specific fiber orientations before it is hardened with polyester resin. The composite plates are shaped according to the standard geometry and uni-axially loaded in order to investigate the tensile responses. Two important parameters are studied such as fiber orientations and number of layers. According to the results, it is shown that...

Eco-friendly surface modification on polyester fabrics by esterase treatment

Energy Technology Data Exchange (ETDEWEB)

Wu, Jindan; Cai, Guoqiang; Liu, Jinqiang; Ge, Huayun; Wang, Jiping, E-mail: jipingwanghz@gmail.com

2014-03-01

Graphical abstract: - Highlights: • We used a simple and easy way to measure the enzyme activity. • We studied the mechanism by characterizing the chemical changes in the surface of fabric. • We studied the advantages in surface wettability, fiber integrity and mechanical performance of cutinase treated fabrics. • Cutinase pretreated fibers exhibited much improved fabric wicking and better fiber integrity comparing to alkali treated ones. • Cutinase pretreatment technology promotes energy conservation and emission reduction. - Abstract: Currently, traditional alkali deweighting technology is widely used to improve the hydrophilicity of polyester fabrics. However, the wastewater and heavy chemicals in the effluent cause enormous damage to the environment. Esterase treatment, which is feasible in mild conditions with high selectivity, can provide a clean and efficient way for polyester modification. Under the optimum conditions, the polyester fabric hydrolysis process of esterase had a linear kinetics. X-ray photoelectron spectrometry (XPS) results showed that hydroxyl and carboxyl groups were produced only on the surface of modified fiber without changing the chemical composition of the bulk. These fibers exhibited much improved fabric wicking, as well as greatly improved oily stain removal performance. Compared to the harsh alkali hydrolysis, the enzyme treatment led to smaller weight loss and better fiber integrity. The esterase treatment technology is promising to produce higher-quality polyester textiles with an environmental friendly approach.

The axial crushes behaviour on foam-filled round Jute/Polyester composite tubes

Science.gov (United States)

Othman, A.; Ismail, A. E.

2018-04-01

The present paper investigates the effect of axial loading compression on jute fibre reinforced polyester composite round tubes. The specimen of composite tube was fabricated by hand lay-up method of 120 mm length with fix 50.8 mm inner diameter to determine the behaviour of energy absorption on number of layers of 450 angle fibre and internally reinforced with and without foam filler material. The foam filler material used in this studies were polyurethane (PU) and polystyrene (PE) with average of 40 and 45 kg/m3 densities on the axial crushing load against displacement relations and on the failure modes. The number of layers of on this study were two; three and four were selected to calculate the crush force efficiency (CFE) and the specific energy absorption (SEA) of the composite tubes. Result indicated that the four layers’ jute/polyester show significant value in term of crushing load compared to 2 and 3 layers higher 60% for 2 layer and 3% compared to 3 layers. It has been found that the specific energy absorption of the jute/polyester tubes with polystyrene foam-filled is found higher respectively 10% to 12% than empty and polyurethane (PU) foam tubes. The increase in the number of layers from two to four increases the mean axial load from 1.01 KN to 3.60 KN for empty jute/polyester and from 2.11 KN to 4.26 KN for the polyurethane (PU) foam-filled jute/polyester tubes as well as for 3.60 KN to 5.58 KN for the polystyrene (PE) foam-filled jute/polyester. The author’s found that the failure of mechanism influence the characteristic of curve load against displacement obtained and conclude that an increasing number of layers and introduce filler material enhance the capability of specific absorbed energy.

Investigation of Mechanical Properties of Unidirectional Steel Fiber/Polyester Composites: Experiments and Micromechanical Predictions

DEFF Research Database (Denmark)

Raghavalu Thirumalai, Durai Prabhakaran; Løgstrup Andersen, Tom; Bech, Jakob Ilsted

2016-01-01

the role of material and process parameters on material properties. Two types of SFRP were studied: polyester resin reinforced by both steel fabric containing unidirectional fibers and steel fibers wound on a metal frame with 0° orientations. The effects of the fiber volume fraction and the role of polymer......The article introduces steel fiber reinforced polymer composites, which is considered new for composite product developments. These composites consist of steel fibers or filaments of 0.21 mm diameter embedded in a polyester resin. The goal of this investigation is to characterize the mechanical...... performance of steel fiber reinforced polyester composites at room temperature. The mechanical properties of unidirectional steel fiber reinforced polyester composites (SFRP) are evaluated experimentally and compared with the predicted values by micro-mechanical models. These predictions help to understand...

Influence of Sawdust Bio-filler on the Tensile, Flexural, and Impact Properties of Mangifera Indica Leaf Stalk Fibre Reinforced Polyester Composites

Directory of Open Access Journals (Sweden)

Heckadka Srinivas Shenoy

2018-01-01

Full Text Available The need to have biodegradable composites is aloft in today’s market as they are environment friendly and are also easy to fabricate. In this study, mangifera indica leaf stalk fibres were used as reinforcement along with saw dust as bio-filler material. Unsaturated isophthalic polyester resin was used as the matrix. The fibres were treated with 6 % vol. NaOH and neutralized with 3 % vol. of dilute HCl. Treatment of sawdust fillers was done by using 2% vol. NaOH solution. Hand layup method and compression moulding technique was used to fabricate the composite laminates. Specimens for evaluating the mechanical properties were prepared by using water jet machining. The results indicated an increase in tensile, flexural and impact strength of composites with addition of sawdust upto 3%. Further addition of the bio-filler resulted in decrease of mechanical properties.

Recent Advances in the Design of Water Based-Flame Retardant Coatings for Polyester and Polyester-Cotton Blends

Directory of Open Access Journals (Sweden)

Jenny Alongi

2016-10-01

Full Text Available Over the last ten years a new trend of research activities regarding the flame retardancy of polymeric materials has arisen. Indeed, the continuous search for new flame retardant systems able to replace the traditional approaches has encouraged alternative solutions, mainly centred on nanotechnology. In this context, the deposition of nanostructured coatings on fabrics appears to be the most appealing and performance suitable approach. To this aim, different strategies can be exploited: from the deposition of a single monolayer consisting of inorganic nanoparticles (single-step adsorption to the building-up of more complex architectures derived from layer by layer assembly (multi-step adsorption. The present paper aims to review the application of such systems in the field of polyester and polyester-cotton blend fabrics. The results collated by the authors are discussed and compared with those published in the literature on the basis of the different deposition methods adopted. A critical analysis of the advantages and disadvantages exhibited by these approaches is also presented.

Thermal studies of poly(esters) containing silicon or germanium in the main chain

International Nuclear Information System (INIS)

Tagle, L.H.; Terraza, C.; Valenzuela, P.; Leiva, A.; Urzua, M.

2005-01-01

The thermal properties of poly(esters) containing Si and/or Ge in the main chain derived from the acid dichlorides bis(4-chloroformyl-phenyl)-dimethyl-silane, bis(4-chloroformyl-phenyl)-dimethyl-germane, bis(4-chloroformyl-phenyl)-diphenyl-silane and bis(4-chloroformyl-phenyl)-diphenyl-silane, and the diphenols bis(4-hydroxyphenyl)-dimethyl-silane, bis(4-hydroxyphenyl)-dimethyl-germane, bis(4-hydroxyphenyl)-diphenyl-silane and bis(4-hydroxyphenyl)-diphenyl-germane were studied by differential scanning calorimetry and dynamic thermogravimetry. Poly(esters) with two Si atoms in the main chain showed higher values of T g than those with two Ge atoms, and the same was observed for poly(esters) with phenyl groups bonded to the heteroatoms, instead of those with methyl groups. Thermal decomposition temperatures were also higher for those poly(esters) with two Si atoms in the main chain and those in which the heteroatom is bonded to phenyl groups, due to the higher polarity of the Si-C bond in front of the Ge-C

ELECTROSPUN MESOFIBERS, A NOVEL BIODEGRADABLE PHEROMONE DISPENSER TECHNOLOGY, ARE COMBINED WITH MECHANICAL DEPLOYMENT FOR EFFICIENT IPM OF LOBESIA BOTRANA IN VINEYARDS.

Science.gov (United States)

Hummel, Hans E; Langner, S S; Breuer, M

2015-01-01

Behaviour modifying pheromones are well known agents for disrupting mating communication of pest insects. For optimal activity, they must be dispensed in time and space at a quantitatively measurable, predetermined release rate covering the flight period of the target species. Pheromones appeal to environmentally conscientious entomologists for their biodegradability, non-toxicity and ecological compatibility. In attempts of combining the virtues of pheromones, suitable slow release dispensers, and their mechanical deployment, an ecologically sensible, reasonably priced and patented procedure was developed and tested with the vineyard pest Lobesia botrana (Lep.: Tortricidae). It is characterized by (1) Electrospun mesofibers with diameters ranging from 0.6 to 3.5 micrometres, containing disruptants and dispensing it by slow release diffusion into the crop, (2) simultaneous application of the fully biodegradable combination of pheromone with Ecoflex polyester mesofiber, (3) combination of mechanical deployment by multi-purpose cultivators of the prefabricated pheromone dispensers with other simultaneous cultivation measures, and thus further reducing labour time and treatment costs. The dispensers are biodegradable within half a year without leaving any objectionable residues. In the standard eco-toxicology tests pheromone dispensers are harmless to non-target organisms. The disruptive effect of one treatment lasts for seven weeks which covers well one of several flight periods of L. botrana.

Polyester fabric coated with Ag/ZnO composite film by magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Yuan, Xiaohong, E-mail: yxhong1981_2004@126.com [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China); Faculty of Clothing and Design, Minjiang University, Fuzhou 350121, Fujian (China); Xu, Wenzheng, E-mail: xwz8199@126.com [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China); Huang, Fenglin, E-mail: windhuang325@163.com [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China); Chen, Dongsheng, E-mail: mjuchen@126.com [Faculty of Clothing and Design, Minjiang University, Fuzhou 350121, Fujian (China); Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn [Key Laboratory of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu (China)

2016-12-30

Highlights: • Ag/ZnO composite film was successfully deposited on polyester fabric by magnetron sputtering technique. • Ag film was easily oxidized into Ag{sub 2}O film in high vacuum oxygen environment. • The zinc film coated on the surface of Ag film before RF reactive sputtering could protect the silver film from oxidation. • Polyester fabric coated with Ag/ZnO composite film can obtained structural color. • The anti-ultraviolet and antistatic properties of polyester fabric coated with Ag/ZnO composite film all were good. - Abstract: Ag/ZnO composite film was successfully deposited on polyester fabric by using direct current (DC) magnetron sputtering and radio frequency (RF) magnetron reaction sputtering techniques with pure silver (Ag) and zinc (Zn) targets. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to examine the deposited film on the fabric. It was found that the zinc film coated on Ag film before RF reactive sputtering could protect the silver film from oxidation. Anti-ultraviolet property and antistatic property of the coated samples using different magnetron sputtering methods were also investigated. The experimental results showed that Ag film was oxidized into in Ag{sub 2}O film in high vacuum oxygen environment. The deposition of Zn film on the surface of the fabric coated with Ag film before RF reactive sputtering, could successfully obtained Ag/ZnO composite film, and also generated structural color on the polyester fabric.

A study on effect of ATH on Euphorbia coagulum modified polyester banana fiber composite

Science.gov (United States)

Kumari, Sanju; Rai, Bhuvneshwar; Kumar, Gulshan

2018-02-01

Fiber reinforced polymer composites are used for building and structural applications due to their high strength. In conventional composites both the binder and the reinforcing fibers are synthetic or either one of the material is natural. In the present study coagulum of Euphorbia royleana has been used for replacing polyester resinas binder in polyester banana composite. Euphorbia coagulum (driedlatex) is rich in resinous mass (60-80%), which are terpenes and polyisoprene (10-20%). Effect of varying percentage of coagulum content on various physico-mechanical properties of polyester-banana composites has been studied. Since banana fiber is sensitive to water due to presence of polar group, banana composite undergoes delamination and deterioration under humid condition. Alkali treated banana fiber along with coagulum content has improved overall mechanical properties and reduction in water absorption. The best physico-mechanical properties have been achieved on replacing 40% of polyester resin by coagulum. An increase of 50% in bending strength, 30% bending modulus and 45% impact strength as well as 68% decrease in water absorption was observed. Incorporation of 20% ATH as flame retardant in coagulum modified banana polyester composite enhanced limiting oxygen index from 20.6 to 26.8% and smoke density reduced up to 40%. This study presents the possibility of utilization of renewable materials for environmental friendly composite development as well as to find out alternative feedstock for petroleum products. Developed Euphorbia latex modified banana polyester composites can have potential utility in hardboard, partition panel, plywood and automotive etc.

Neutron shielding performance of water-extended polyester

International Nuclear Information System (INIS)

Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M.; Vega Carrillo, H.R.; Hernandez-Davila, V.M.; Gallego, E.; Lorente, A.

2006-01-01

A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester (WEP) was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (MCNP code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a 252 Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

Neutron shielding performance of water-extended polyester

Energy Technology Data Exchange (ETDEWEB)

Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M. [Zacatecas Univ. Autonoma, Nuclear Studies (Mexico); Vega Carrillo, H.R.; Hernandez-Davila, V.M. [Zacatecas Univ. Autonoma, Electric Engineering Academic Units (Mexico); Gallego, E.; Lorente, A. [Madrid Univ. Politecnica, cNuclear Engineering Department (Mexico)

2006-07-01

A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester (WEP) was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (MCNP code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a {sup 252}Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

Azobenzene side-chain liquid crystalline polyesters with outstanding optical storage properties

DEFF Research Database (Denmark)

Hvilsted, Søren; Pedersen, M; Holme, NCR

1998-01-01

A flexible azobenzene side-chain liquid crystalline (SCLC) polyester architecture employed for reversible optical storage is described. The modular design allows four structural parameters to be individually modified. These parameters: i- the methylene side-chain spacer length, ii- the substituent......,000 are routinely obtained by melt transesterification of the novel diols and selected diacid precursors (parameter iii). Prominent storage features include no prealignment of thin SCLC polyester films prior to the writing process, and sensitivity in a broad laser wavelength window (415-532 nm). Additionally...... sign of fatigue. The non-destructive read out is performed with red light (600-750 nm). Finally, erasing the information can be achieved by heating the polyester film to 80 degrees C or irradiating it briefly with UV-light. In the latter case at least 10,000 write, read and erase cycles are possible...

Effect of Argon Plasma Treatment Variables on Wettability and Antibacterial Properties of Polyester Fabrics

Science.gov (United States)

Senthilkumar, Pandurangan; Karthik, Thangavelu

2016-04-01

In this research work, the effect of argon plasma treatment variables on the comfort and antibacterial properties of polyester fabric has been investigated. The SEM micrographs and FTIR analysis confirms the modification of fabric surface. The Box-Behnken design was used for the optimization of plasma process variables and to evaluate the effects and interactions of the process variables, i.e. operating power, treatment time and distance between the electrodes on the characteristics of polyester fabrics. The optimum conditions of operating power 600 W, treatment time 30 s, and the distance between the electrodes of 2.8 mm was arrived using numerical prediction tool in Design-Expert software. The plasma treated polyester fabrics showed better fabric characteristics particularly in terms of water vapour permeability, wickability and antibacterial activity compared to untreated fabrics, which confirms that the modified structure of polyester fabric.

Studies on biodegradable and crosslinkable poly(castor oil fumarate)/poly(propylene fumarate) composite adhesive as a potential injectable biomaterial.

Science.gov (United States)

Mitha, M K; Jayabalan, M

2009-12-01

Biodegradable hydroxyl terminated-poly(castor oil fumarate) (HT-PCF) and poly(propylene fumarate) (HT-PPF) resins were synthesized as an injectable and in situ-cross linkable polyester resins for orthopedic applications. An injectable adhesive formulation containing this resin blend, N-vinyl pyrrolidone (NVP), hydroxy apatite, free radical initiator and accelerator was developed. The Composite adhesives containing the ratio of resin blend and NVP, 2.1:1.5, 2.1:1.2 and 2.1:1.0 set fast with tolerable exothermic temperature as a three dimensionally cross linked toughened material. Crosslink density and mechanical properties of the crosslinked composite increase with increase of NVP. The present crosslinked composite has hydrophilic character and cytocompatibility with L929 fibroblast cells.

Synthesis and characterization of saturated polyester and ...

Indian Academy of Sciences (India)

but which can actually be used for processes, which pro- duce interesting ... ing the synthesis of saturated polyester (from GPET waste). This has been done for the .... The solid product obtained from the glycolysis of PET was bis(hydroxy ethyl ...

Influence of fibre treatments on mechanical properties of short Sansevieria cylindrica/polyester composites

International Nuclear Information System (INIS)

Sreenivasan, V.S.; Ravindran, D.; Manikandan, V.; Narayanasamy, R.

2012-01-01

Highlights: ► Fibre treatments were performed to improve interfacial bond between SCF and matrix. ► Mechanical properties of treated SCFP composites are greater than USCFP composites. ► PSCFP composites show maximum mechanical properties among treated SCFP composites. ► SEM analysis revealed that the wetting of PSCFs by the polyester resin was good. ► KMnO 4 treatment is ideal treatment for SCFs to get optimum mechanical properties. -- Abstract: In the present study, to improve the interfacial bond between Sansevieria cylindrica fibres (SCFs) and polyester matrix, chemical surface treatments have been performed on the fibres. Treatments including alkali, benzoyl peroxide, potassium permanganate and stearic acid were carried out to modify the fibre surface. Raw and each type of treated SCF samples were utilised separately for fabricating the composites. The mechanical properties of composites prepared from the chemically treated SCFs are found to be much better than those of the untreated ones. Potassium-permanganate-treated S. cylindrica fibre/polyester (PSCFP) composites showed optimum mechanical properties among the treated S. cylindrica fibre/polyester (SCFP) composites. The surface morphologies of fracture surfaces of composites were recorded using scanning electron microscopy (SEM). The SEM micrographs reveal that interfacial bonding between potassium-permanganate-treated SCF (PSCF) and polyester matrix has significantly improved, suggesting that better dispersion of PSCF into the matrix has occurred upon potassium permanganate treatment of SCF.

Biocompatible Porous Polyester-Ether Hydrogel Scaffolds with Cross-Linker Mediated Biodegradation and Mechanical Properties for Tissue Augmentation

Directory of Open Access Journals (Sweden)

Berkay Ozcelik

2018-02-01

Full Text Available Porous polyester-ether hydrogel scaffolds (PEHs were fabricated using acid chloride/alcohol chemistry and a salt templating approach. The PEHs were produced from readily available and cheap commercial reagents via the reaction of hydroxyl terminated poly(ethylene glycol (PEG derivatives with sebacoyl, succinyl, or trimesoyl chloride to afford ester cross-links between the PEG chains. Through variation of the acid chloride cross-linkers used in the synthesis and the incorporation of a hydrophobic modifier (poly(caprolactone (PCL, it was possible to tune the degradation rates and mechanical properties of the resulting hydrogels. Several of the hydrogel formulations displayed exceptional mechanical properties, remaining elastic without fracture at compressive strains of up to 80%, whilst still displaying degradation over a period of weeks to months. A subcutaneous rat model was used to study the scaffolds in vivo and revealed that the PEHs were infiltrated with well vascularised tissue within two weeks and had undergone significant degradation in 16 weeks without any signs of toxicity. Histological evaluation for immune responses revealed that the PEHs incite only a minor inflammatory response that is reduced over 16 weeks with no evidence of adverse effects.

Preparation and properties of high storage stability polyester polyol dispersion for two-component waterborne polyurethane coating

Science.gov (United States)

Hao, H.; Hu, J. Q.; Wang, F.; Tu, W. P.

2017-01-01

A new type of polyester polyol dispersion with good storage stability was prepared based on a hydrophilic monomer 5-sodium sulfodimethyl isophthalate (5-SIPM), and frequently-used monomers such as neopentyl glycol (NPG), dimethyl terephthalate (DMT), dimethyl phthalate (DMP) and trimethylolpropane (TMP) by the transpolycondensation and polycondensation method. The polyester polyol dispersion was characterized by FTIR and GPC. The proper content of these monomers were determined by the performance of polyester dispersion: the content of TMP was 15wt%, the content of NPG was 7.5wt% and the hydrophilic monomer 5-SIPM content was 5wt%. Two-component waterborne polyurethane (2K-WPU) coatings were prepared by Bayhydur® XP2487/1 and polyester polyol dispersions, which were stored before and after at 40 ° for 6 weeks, the prepared films have no differences in drying time, adhesion, pencil hardness, gloss and chemical resistance, the result also reveals that the polyester polyol dispersion have excellent storage stability resistance.

Neutron shielding performance of water-extended polyester

International Nuclear Information System (INIS)

Vega Carrillo, H.R.; Manzanares-Acuna, E.; Hernandez-Davila, V.M.; Vega Carrillo, H.R.; Gallegoc, E.; Lorentec, A.; Hernandez-Davila, V.M.

2006-01-01

A Monte Carlo study to determine the shielding features to neutrons of water-extended polyester was carried out. Materials with low atomic number are predominantly used for neutron shielding because these materials effectively attenuate neutrons, mainly through elastic and inelastic collisions. In addition to neutron attenuation properties, other desirable properties for neutron shielding materials include mechanical strength, stability, low cost, and ease of handling. During the selection of materials to design a neutron shield, prompt gamma production as well as radionuclide induced by neutron activation must be considered. In this investigation the Monte Carlo method (M.C.N.P. code) was used to evaluate the performance of a water-extended polyester shield designed for the transportation, storage, and use of a 252 Cf isotopic neutron source, for comparison the calculations were extended to water shielding, the bare source in vacuum and in air. (authors)

Mechanical Characterization of Cotton Fiber/Polyester Composite Material

Directory of Open Access Journals (Sweden)

Altaf Hussain Rajper

2014-04-01

Full Text Available Development of composite from natural fiber for lower structural application is growing for long-term sustainable perspective. Cotton fiber composite material has the added advantages of high specific strength, corrosion resistance, low cost and low weight compared to glass fiber on the expense of internal components of IC engines. The primary aim of the research study is to examine the effect of the cotton fiber on mechanical properties of lower structural applications when added with the polyester resin. In this paper composite material sample has been prepared by hand Lay-Up process. A mould is locally developed in the laboratory for test sample preparation. Initially samples of polyester resin with appropriate ratio of the hardener were developed and tested. At the second stage yarns of cotton fiber were mixed with the polyester resin and sample specimens were developed and tested. Relative effect of the cotton as reinforcing agent was examined and observed that developed composite specimen possess significant improvement in mechanical properties such as tensile strength was improved as 19.78 % and modulus of elasticity was increased up to 24.81%. Through this research it was also observed that developed composite material was of ductile nature and its density decreases up to 2.6%. Results from this study were compared with relevant available advanced composite materials and found improved mechanical properties of developed composite material

Aerobic biodegradation of a nonylphenol polyethoxylate and toxicity of the biodegradation metabolites.

Science.gov (United States)

Jurado, Encarnación; Fernández-Serrano, Mercedes; Núñez-Olea, Josefa; Lechuga, Manuela

2009-09-01

In this paper a study was made of the biodegradation of a non-ionic surfactant, a nonylphenol polyethoxylate, in biodegradability tests by monitoring the residual surfactant matter. The influence of the concentration on the extent of primary biodegradation, the toxicity of biodegradation metabolites, and the kinetics of degradation were also determined. The primary biodegradation was studied at different initial concentrations: 5, 25 and 50 mg/L, (at sub-and supra-critical micelle concentration). The NPEO used in this study can be considered biodegradable since the primary biodegradation had already taken place (a biodegradation greater than 80% was found for the different initial concentration tested). The initial concentration affected the shape of the resulting curve, the mean biodegradation rate and the percentage of biodegradation reached (99% in less than 8 days at 5 mg/L, 98% in less than 13 days at 25 mg/L and 95% in 14 days at 50 mg/L). The kinetic model of Quiroga and Sales (1991) was applied to predict the biodegradation of the NPEO. The toxicity value was measured as EC(20) and EC(50). In addition, during the biodegradation process of the surfactant a toxicity analysis was made of the evolution of metabolites generated, confirming that the subproducts of the biodegradation process were more toxic than the original.

Acetalised Galactarate Polyesters: Interplay between Chemical Structure and Polymerisation Kinetics

Directory of Open Access Journals (Sweden)

Ionela Gavrila

2018-02-01

Full Text Available In spite of the progress that has made so far in the recent years regarding the synthesis of bio-based polymers and in particular polyesters, only few references address the optimisation of these new reactions with respect to conversion and reaction time. Related to this aspect, we here describe the transesterification reaction of two different acetalised galactarate esters with a model aliphatic diol, 1,6-hexanediol. The kinetics of these two apparently similar reactions is compared, with a focus on the conversion while varying the concentration of a di-butyltin oxide catalyst (DBTO, respectively, the used N2 flow-rate. During the first stage of polymerisation, the molecular weight of the end-products is more than doubled when using a 250 mL/min flow as opposed to an almost static N2 pressure. Additionally, the resulted pre-polymers are subjected to further polycondensation and the comparison between the obtained polyesters is extended to their thermal, mechanical and dielectrical characterisation. The influence of the acetal groups on the stability of the polyesters in acidic conditions concludes the study.

Biodegradability and biodegradation rate of poly(caprolactone)-starch blend and poly(butylene succinate) biodegradable polymer under aerobic and anaerobic environment.

Science.gov (United States)

Cho, H S; Moon, H S; Kim, M; Nam, K; Kim, J Y

2011-03-01

The biodegradability and the biodegradation rate of two kinds biodegradable polymers; poly(caprolactone) (PCL)-starch blend and poly(butylene succinate) (PBS), were investigated under both aerobic and anaerobic conditions. PCL-starch blend was easily degraded, with 88% biodegradability in 44 days under aerobic conditions, and showed a biodegradation rate of 0.07 day(-1), whereas the biodegradability of PBS was only 31% in 80 days under the same conditions, with a biodegradation rate of 0.01 day(-1). Anaerobic bacteria degraded well PCL-starch blend (i.e., 83% biodegradability for 139 days); however, its biodegradation rate was relatively slow (6.1 mL CH(4)/g-VS day) compared to that of cellulose (13.5 mL CH(4)/g-VS day), which was used as a reference material. The PBS was barely degraded under anaerobic conditions, with only 2% biodegradability in 100 days. These results were consistent with the visual changes and FE-SEM images of the two biodegradable polymers after the landfill burial test, showing that only PCL-starch blend had various sized pinholes on the surface due to attack by microorganisms. This result may be use in deciding suitable final disposal approaches of different types of biodegradable polymers in the future. Copyright © 2010 Elsevier Ltd. All rights reserved.

Proceedings of biodegradation

International Nuclear Information System (INIS)

Anon.

1990-01-01

This book contains the proceedings of Biodegradation. Topics include:biodegradation using the tools of biotechnology, basic science aspects of biodegradation, the physiological characteristics of microorganisms, the use of selective techniques that enhance the process of microbial evolution of biodegradative genes in nature, the genetic characteristics of microorganisms allowing them to biodegrade both natural and synthetic toxic chemicals, the molecular techniques that allow selective assembly of genetic segments form a variety of bacterial strains to a single strain, and methods needed to advance biodegradation research as well as the high-priority chemical problems important to the Department of Defense or to the chemical industry

Effect of structural parameters on burning behavior of polyester fabrics having flame retardancy property

Science.gov (United States)

Çeven, E. K.; Günaydın, G. K.

2017-10-01

The aim of this study is filling the gap in the literature about investigating the effect of yarn and fabric structural parameters on burning behavior of polyester fabrics. According to the experimental design three different fabric types, three different weft densities and two different weave types were selected and a total of eighteen different polyester drapery fabrics were produced. All statistical procedures were conducted using the SPSS Statistical software package. The results of the Analysis of Variance (ANOVA) tests indicated that; there were statistically significant (5% significance level) differences between the mass loss ratios (%) in weft and mass loss ratios (%) in warp direction of different fabrics calculated after the flammability test. The Student-Newman-Keuls (SNK) results for mass loss ratios (%) both in weft and warp directions revealed that the mass loss ratios (%) of fabrics containing Trevira CS type polyester were lower than the mass loss ratios of polyester fabrics subjected to washing treatment and flame retardancy treatment.

Polyesters production from the mixture of phthalic acid, terephthalic and glycerol

International Nuclear Information System (INIS)

Carvalho, A.L.S.; Oliveira, J.C.; Miranda, C.S.; Boaventura, J.S.; Jose, N.M.; Carvalho, R.F.

2010-01-01

Glycerin, a byproduct of biodiesel is currently an environmental and economic problem for producers of this renewable fuel in Brazil and in others parts of the world. In order to offer new proposals for recovery, it is used for the manufacture of polyesters used in applications in diverse areas such as construction and automobile industry. This work reports the production of polymer from the mixture of terephthalic and phthalic acid in three different proportions. The polyesters showed good thermal stability, analyzed by TGA and DSC, with an increase proportional to the terephthalic acid content. The X-ray diffraction patterns show that the samples are semi crystalline polymers. The micrographs indicated the presence of a smoother surface in the polyester that has a larger amount of phthalic acid, as reported in the literature. Therefore, the materials showed good thermal properties and morphological characteristics, so it consists in a new alternative to use glycerin. (author)

Development of a readily recyclable sound insulation material made of polyester fibers. Application of the PET fibers from plastic bottles; Recycle kanona jidoshayo polyester sei kyuon zairyo no kaihatsu. Shiyozumi pet bottle zai no insulator zai eno tekiyo

Energy Technology Data Exchange (ETDEWEB)

Nemoto, K; Watanabe, K; Sugawara, H; Minemura, Y [Nissan Motor Co. Ltd., Tokyo (Japan)

1997-10-01

We have developed new polyester sound-absorbing materials made of fine and modified-cross-section polyester fabric. They provide noticeably higher sound-absorbing performance than traditional materials. Another feature of the new materials is their excellent recyclability since they are made of polyester. Application of the new materials to the dash silencer and the floor carpeting produced a great improvement in sound-insulation performance with less weight. 2 refs., 7 figs.

Effect of Structure Change on Radiation Crosslinking of Unsaturated Polyesters

International Nuclear Information System (INIS)

Ranogajec, F.

2006-01-01

During the course of crosslinking of unsaturated polyesters reacting system, that was liquid prior to reaction, gels, and becomes solid. Crosslinking reaction begins to be controlled by the change of the physical state of the system at an early stage of reaction. The kinetics can not be studied by the usual kinetical methods. In-source 60 C o gamma rays induced crosslinking of unsaturated polyester with styrene was followed directly and continuously by measuring electrical conductivity change. The results of extraction analysis proved good correlation between the change of electrical conductivity and the extent of curing. The gel content was inversely proportional to conductivity and free styrene content directly proportional to conductivity. DC-electrical conductivity has shown high sensitivity toward structural changes and enabled us to detect liquid-liquid transitions in unsaturated polyester. The upper liquid-liquid transition (T l ρ) is less known transition caused by a stepwise decrease of intramolecular short-range local order that remains above the glass and lower liquid-liquid transitions. The local order is based on secondary valent interactions and is enhanced by hydrogen bonding. The linear temperature dependence of the viscosity and dc electrical conductivity of unsaturated polyesters showed a change of slope caused by the (T l ρ). Those changes were the result of the diminishing of the local order (which includes several bond lengths) caused by breaking of the intramolecular interactions. The intramolecular nature of the (T l ρ) in the polyesters under consideration was proved by its insensitivity to crosslinking and dilution with solvents. In the corresponding temperature range, DSC thermograms shoved expected endothermic changes. The structure changes related to the (T l ρ) in the investigated polyesters were determined by 1 H NMR and NIR spectroscopy. The proton NMR indicated that the stepwise change in hydrogen bonding occurred in the

Synthesis of Improved Polyester Resins.

Science.gov (United States)

1979-07-05

of this page) 21. No. of Pages 22. Price* Unclassified Unclassified 83 For sale by the National Technical Information Service, Springfield. Virginia...low sensitivity .... ........... 68 B2B C-scan of carbon fiber reinforced polyester Laminate #2 at high sensitivity ..... .......... 68 B3A C-scan of...right corner, but it is obscured by the delamination. Figure B2B shows the same composite at a 12 decibel increase in sensitivity. The image now shows

Photoinduced anisotropy in a family of amorphous azobenzene polyesters for optical storage

DEFF Research Database (Denmark)

Nedelchev, Lian; Matharu, Avtar S.; Hvilsted, Søren

2003-01-01

of E1aX polymers characterized by two-ring aromatic substituent in the main chain is a good candidate for optical data storage media. A recording energy of approximately 2 J/cm(2) is sufficient to induce high refractive-index modulations of Deltan = 0.13 in these materials, which is retained even......We investigate parameters associated with optical data storage in a variety of amorphous side-chain azobenzene-containing polyesters denoted as E1aX. The polyesters possess a common cyano-substituted azobenzene chromophore as a side chain, but differ in their main-chain polyester composition....... Seventeen different polymers from the E1aX family divided into four classes, depending on the type of the main-chain substituent (one-, two-, and three-ring aromatic or alicyclic) have been thoroughly investigated. Various parameters characterizing the photoinduced birefringence in these materials...

Simulation on the Performance of a Driven Fan Made by Polyester/Epoxy interpenetrate polymer network (IPN)

Science.gov (United States)

Fahrul Hassan, Mohd; Jamri, Azmil; Nawawi, Azli; Zaini Yunos, Muhamad; Fauzi Ahmad, Md; Adzila, Sharifah; Nasrull Abdol Rahman, Mohd

2017-08-01

The main purpose of this study is to investigate the performance of a driven fan design made by Polyester/Epoxy interpenetrate polymer network (IPN) material that specifically used for turbocharger compressor. Polyester/Epoxy IPN is polymer plastics that was used as replacements for traditional polymers and has been widely used in a variety of applications because of their limitless conformations. Simulation based on several parameters which are air pressure, air velocity and air temperature have been carried out for a driven fan design performance of two different materials, aluminum alloy (existing driven fan design) and Polyester/Epoxy IPN using SolidWorks Flow Simulation software. Results from both simulations were analyzed and compared where both materials show similar performance in terms of air pressure and air velocity due to similar geometric and dimension, but Polyester/Epoxy IPN produces lower air temperature than aluminum alloy. This study shows a preliminary result of the potential Polyester/Epoxy IPN to be used as a driven fan design material. In the future, further studies will be conducted on detail simulation and experimental analysis.

Solid-State Polymerization of Poly(Ethylene Furanoate Biobased Polyester, II: An Efficient and Facile Method to Synthesize High Molecular Weight Polyester Appropriate for Food Packaging Applications

Directory of Open Access Journals (Sweden)

Nejib Kasmi

2018-04-01

Full Text Available The goal of this study was to synthesize, through a facile strategy, high molecular weight poly(ethylene furanoate (PEF, which could be applicable in food packaging applications. The efficient method to generate PEF with high molecular weight consists of carrying out a first solid-state polycondensation under vacuum for 6 h reaction time at 205 °C for the resulting polymer from two-step melt polycondensation process, which is catalyzed by tetrabutyl titanate (TBT. A remelting step was thereafter applied for 15 min at 250 °C for the obtained polyester. Thus, the PEF sample was ground into powder, and was then crystallized for 6 h at 170 °C. This polyester is then submitted to a second solid-state polycondensation (SSP carried out at different reaction times (1, 2, 3.5, and 5 h and temperatures 190, 200, and 205 °C, under vacuum. Ultimately, a significant increase in intrinsic viscosity is observed with only 5 h reaction time at 205 °C during the second SSP being needed to obtain very high molecular weight PEF polymer greater than 1 dL/g, which sufficient for manufacturing purposes. Intrinsic viscosity (IV, carboxyl end-group content (–COOH, and thermal properties, via differential scanning calorimetry (DSC, were measured for all resultant polyesters. Thanks to the post-polymerization process, DSC results showed that the melting temperatures of the prepared PEF samples were steadily enhanced in an obvious way as a function of reaction time and temperature increase. It was revealed, as was expected for all SSP samples, that the intrinsic viscosity and the average molecular weight of PEF polyester increased with increasing SSP time and temperature, whereas the number of carboxyl end-group concentration was decreased. A simple kinetic model was also developed and used to predict the time evolution of polyesters IV, as well as the carboxyl and hydroxyl end-groups of PEF during the SSP.

Clinical outcomes after parastomal hernia repair with a polyester monofilament composite mesh

DEFF Research Database (Denmark)

Oma, E; Pilsgaard, B; Jorgensen, L N

2018-01-01

with intraperitoneal placement of a polyester monofilament macroporous composite mesh. METHODS: Data on all patients undergoing parastomal hernia repair with Parietex™ Composite Parastomal Mesh at our institution during a 4-year period were examined. Patients with urostomy were excluded. A team of three experienced...... chronic pain. CONCLUSION: In this study, we found low rates of recurrence and chronic pain following parastomal hernia repair using intraperitoneal reinforcement with a polyester monofilament composite mesh....

The Degradation of Mechanical Properties in Halloysite Nanoclay-Polyester Nanocomposites Exposed in Seawater Environment

Directory of Open Access Journals (Sweden)

Mohd Shahneel Saharudin

2016-01-01

Full Text Available Polyester based polymers are extensively used in aggressive marine environments; however, inadequate data is available on the effects of the seawater on the polyester based nanocomposites mechanical properties. This paper reports the effect of seawater absorption on the mechanical properties degradation of halloysite nanoclay-polyester nanocomposites. Results confirmed that the addition of halloysite nanoclay into polyester matrix was found to increase seawater uptake and reduce mechanical properties compared to monolithic polyester. The maximum decreases in microhardness, tensile and flexural properties, and impact toughness were observed in case of 1 wt% nanoclay. The microhardness decreased from 107 HV to 41.7 HV (61% decrease. Young’s modulus decreased from 0.6 GPa to 0.4 GPa (33% decrease. The flexural modulus decreased from 0.6 GPa to 0.34 GPa (43% decrease. The impact toughness dropped from 0.71 kJ/m2 to 0.48 kJ/m2 (32% decrease. Interestingly, the fracture toughness KIC increased with the addition of halloysite nanoclay due to the plasticization effect of the resin matrix. SEM images revealed the significant reduction in mechanical properties in case of 1 wt% reinforcement which is attributed to the degradation of the nanoclay-matrix interface influenced by seawater absorption and agglomeration of halloysite nanoclay.

Macromolecular Engineering: New Routes Towards the Synthesis of Well-??Defined Polyethers/Polyesters Co/Terpolymers with Different Architectures

KAUST Repository

Alamri, Haleema

2016-05-18

The primary objective of this research was to develop a new and efficient pathway for well-defined multicomponent homo/co/terpolymers of cyclic esters/ethers using an organocatalytic approach with an emphasis on the macromolecular engineering aspects of the overall synthesis. Macromolecular engineering (as discussed in the first chapter) of homo/copolymers refers to the specific tailoring of these materials for achieving an easy and reproducible synthesis that results in precise molecular characteristics, i.e. molecular weight and polydispersity, as well as specific structure and end?group choices. Precise control of these molecular characteristics will provide access to new materials that can be used for pre-targeted purposes such as biomedical applications. Among the most commonly used engineering materials are polyesters (biocompatible and biodegradable) and polyethers (biocompatible), either as homopolymers or when or copolymers with linear structures. The ability to create non-linear structures, for example stars, will open new horizons in the applications of these important polymeric materials. The second part of this thesis describes the synthesis of aliphatic polyesters, particularly polycaprolactone and polylactide, using a metal-free initiator/catalyst system. A phosphazene base (t?BuP2) was used as the catalyst for the ring-opening copolymerization of ?-aprolactone (??CL) and L,Lactide (LLA) at room temperature with a variety of protic initiators in different solvents. These studies provided important information for the design of a metal-free route toward the synthesis of polyester?based (bio) materials. The third part of the thesis describes a novel route for the one?pot synthesis of polyether-b polyester block copolymers with either a linear or a specific macromolecular architecture. Poly (styrene oxide)?b?poly(caprolactone)?b?poly(L,lactide) was prepared using this method with the goal of synthesizing poly(styrene oxide)-based materials since this

Adsorption of uranium ions by crosslinked polyester resin functionalized with acrylic acid from aqueous solutions

International Nuclear Information System (INIS)

Cemal Oezeroglu; Niluefer Metin

2012-01-01

In this paper, the crosslinked polyester resin containing acrylic acid functional groups was used for the adsorption of uranium ions from aqueous solutions. For this purpose, the crosslinked polyester resin of unsaturated polyester in styrene monomer (Polipol 353, Poliya) and acrylic acid as weight percentage at 80 and 20%, respectively was synthesized by using methyl ethyl ketone peroxide (MEKp, Butanox M60, Azo Nobel)-cobalt octoate initiator system. The adsorption of uranium ions on the sample (0.05 g copolymer and 5 mL of U(VI) solution were mixed) of the crosslinked polyester resin functionalized with acrylic acid was carried out in a batch reactor. The effects of adsorption parameters of the contact time, temperature, pH of solution and initial uranium(VI) concentration for U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid were investigated. The adsorption data obtained from experimental results depending on the initial U(VI) concentration were analyzed by the Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The adsorption capacity and free energy change were determined by using D-R isotherm. The obtained experimental adsorption data depending on temperature were evaluated to calculate the thermodynamic parameters of enthalpy (ΔH o ), entropy (ΔS o ) and free energy change (ΔG o ) for the U(VI) adsorption on the crosslinked polyester resin functionalized with acrylic acid from aqueous solutions. The obtained adsorption data depending on contact time were analyzed by using adsorption models such as the modified Freundlich, Elovich, pseudo-first order and pseudo-second-order kinetic models. (author)

Catalyst Influence on Undesired Side Reactions in the Polycondensation of Fully Bio-Based Polyester Itaconates

Directory of Open Access Journals (Sweden)

Ina Schoon

2017-12-01

Full Text Available Bio-based unsaturated polyester resins derived from itaconic acid can be an alternative to established resins of this type in the field of radical-curing resins. However, one of the challenges of these polyester itaconates is the somewhat more elaborate synthetic process, especially under polycondensation conditions used on an industrial scale. The α,β-unsaturated double bond of the itaconic acid is prone to side reactions that can lead to the gelation of the polyester resin under standard conditions. This is especially true when bio-based diols such as 1,3-propanediol or 1,4-butanediol are used to obtain resins that are 100% derived from renewable resources. It was observed in earlier studies that high amounts of these aliphatic diols in the polyester lead to low conversion and gelation of the resins. In this work, a catalytic study using different diols was performed in order to elucidate the reasons for this behavior. It was shown that the choice of catalyst has a crucial influence on the side reactions occurring during the polycondensation reactions. In addition, the side reactions taking place were identified and suppressed. These results will allow for the synthesis of polyester itaconates on a larger scale, setting the stage for their industrial application.

Influence of the substituent on azobenzene side-chain polyester optical storage materials

DEFF Research Database (Denmark)

Pedersen, M; Hvilsted, Søren; Holme, NCR

1999-01-01

, chloro, and bromo. C-13 NMR spectroscopic and molecular mass investigations substantiate good film forming characteristics. The optical storage performance of thin polyester films are investigated through polarization holography. The resulting diffraction efficiency is mapped and discussed as a function...... of irradiation power and exposure time. Polytetradecanedioates with cyano-, nitro-, methyl-, fluoro-, or trinuoromethyl-azobenzene reach more than 50% diffraction efficiency. Investigations of anisotropy induced at different temperatures reveal that the polyesters are only photosensitive in a narrow temperature...

Micro-thermal analysis of polyester coatings

Science.gov (United States)

Fischer, Hartmut R.

2010-04-01

The application and suitability of micro-thermal analysis to detect changes in the chemical and physical properties of coating due to ageing and especially photo-degradation is demonstrated using a model polyester coating based on neopentyl glycol isophthalic acid. The changes in chemical structure like chain scission and cross-linking are manifested by a shift of the LTA detectable Tg and by a change of the slope of the part of the LTA graph responsible for the penetration of the hot sensor into the material after passing the glass transition temperature. As such LTA is a valuable tool to have a quick look into coating surfaces and especially their ageing. The photo-degradation of polyester in air leads to the formation of a cross-linked network at a surface layer of about 3-4 μm coupled with an increase in hardness and of the glass transition temperature by ˜90 K, the effect is less drastic for a photo-degradation in a nitrogen environment. Moreover, the presence of a non-equilibrium dense surface layer with a higher Tg formed during the drying of the coating formulation and the film solidification can be shown.

Laboratory and Field Evaluation of Biodegradable Polyesters for Sustained Release of Isometamidium and Ethidium

Directory of Open Access Journals (Sweden)

S Geerts

1999-03-01

Full Text Available An overview is presented of the results obtained with biodegradable sustained release devices (SRDs containing a mixture of polymers and either isometamidium (ISMM or ethidium. Under controlled laboratory conditions (monthly challenge with tsetse flies infected with Trypanosoma congolense the protection period in SRD treated cattle could be extended by a factor 2.8 (for ethidium up to 4.2 (for ISMM as compared to animals treated intramuscularly with the same drugs. Using a competitive drug ELISA ISMM concentrations were detected up to 330 days after the implantation of the SRDs, whereas after i.m. injection the drug was no longer present three to four months post treatment. Two field trials carried out in Mali under heavy tsetse challenge showed that the cumulative infection rate was significantly lower in the ISMM-SRD implanted cattle than in those which received ISMM intramuscularly. Using ethidium SRD, however, contradictory results were obtained in field trials in Zambia and in Mali. The potential advantages and inconvenients of the use of SRDs are discussed and suggestions are made in order to further improve the currently available devices.

Study on Energy Absorption Capacity of Steel-Polyester Hybrid Fiber Reinforced Concrete Under Uni-axial Compression

Science.gov (United States)

Chella Gifta, C.; Prabavathy, S.

2018-05-01

This work presents the energy absorption capacity of hybrid fiber reinforced concrete made with hooked end steel fibers (0.5 and 0.75%) and straight polyester fibers (0.5, 0.8, 1.0 and 2.0%). Compressive toughness (energy absorption capacity) under uni-axial compression was evaluated on 100 × 200 mm size cylindrical specimens with varying steel and polyester fiber content. Efficiency of the hybrid fiber reinforcement is studied with respect to fiber type, size and volume fractions in this investigation. The vertical displacement under uni-axial compression was measured under the applied loads and the load-deformation curves were plotted. From these curves the toughness values were calculated and the results were compared with steel and polyester as individual fibers. The hybridization of 0.5% steel + 0.5% polyester performed well in post peak region due to the addition of polyester fibers with steel fibers and the energy absorption value was 23% greater than 0.5% steel FRC. Peak stress values were also higher in hybrid series than single fiber and based on the results it is concluded that hybrid fiber reinforcement improves the toughness characteristics of concrete without affecting workability.

Biodegradable Polymers

OpenAIRE

Vroman, Isabelle; Tighzert, Lan

2009-01-01

Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

Intimately coupling of photolysis accelerates nitrobenzene biodegradation, but sequential coupling slows biodegradation

Energy Technology Data Exchange (ETDEWEB)

Yang, Lihui [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Zhang, Yongming, E-mail: zhym@shnu.edu.cn [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Bai, Qi; Yan, Ning; Xu, Hua [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Rittmann, Bruce E. [Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, Tempe, AZ 85287-5701 (United States)

2015-04-28

Highlights: • Intimately coupled UV photolysis accelerated nitrobenzene biodegradation. • NB biodegradation was slowed by accumulation of nitrophenol. • Oxalic acid was a key product of UV photolysis. • Oxalic acid accelerated biodegradation of nitrobenzene and nitrophenol by a co-substrate effect. • Intimate coupling of UV and biodegradation accentuated the benefits of oxalic acid. - Abstract: Photo(cata)lysis coupled with biodegradation is superior to photo(cata)lysis or biodegradation alone for removal of recalcitrant organic compounds. The two steps can be carried out sequentially or simultaneously via intimate coupling. We studied nitrobenzene (NB) removal and mineralization to evaluate why intimate coupling of photolysis with biodegradation was superior to sequential coupling. Employing an internal circulation baffled biofilm reactor, we compared direct biodegradation (B), biodegradation after photolysis (P + B), simultaneous photolysis and biodegradation (P&B), and biodegradation with nitrophenol (NP) and oxalic acid (OA) added individually and simultaneously (B + NP, B + OA, and B + NP + OA); NP and OA were NB’s main UV-photolysis products. Compared with B, the biodegradation rate P + B was lower by 13–29%, but intimately coupling (P&B) had a removal rate that was 10–13% higher; mineralization showed similar trends. B + OA gave results similar to P&B, B + NP gave results similar to P + B, and B + OA + NP gave results between P + B and P&B, depending on the amount of OA and NP added. The photolysis product OA accelerated NB biodegradation through a co-substrate effect, but NP was inhibitory. Although decreasing the UV photolysis time could minimize the inhibition impact of NP in P + B, P&B gave the fastest removal of NB by accentuating the co-substrate effect of OA.

Intimately coupling of photolysis accelerates nitrobenzene biodegradation, but sequential coupling slows biodegradation

International Nuclear Information System (INIS)

Yang, Lihui; Zhang, Yongming; Bai, Qi; Yan, Ning; Xu, Hua; Rittmann, Bruce E.

2015-01-01

Highlights: • Intimately coupled UV photolysis accelerated nitrobenzene biodegradation. • NB biodegradation was slowed by accumulation of nitrophenol. • Oxalic acid was a key product of UV photolysis. • Oxalic acid accelerated biodegradation of nitrobenzene and nitrophenol by a co-substrate effect. • Intimate coupling of UV and biodegradation accentuated the benefits of oxalic acid. - Abstract: Photo(cata)lysis coupled with biodegradation is superior to photo(cata)lysis or biodegradation alone for removal of recalcitrant organic compounds. The two steps can be carried out sequentially or simultaneously via intimate coupling. We studied nitrobenzene (NB) removal and mineralization to evaluate why intimate coupling of photolysis with biodegradation was superior to sequential coupling. Employing an internal circulation baffled biofilm reactor, we compared direct biodegradation (B), biodegradation after photolysis (P + B), simultaneous photolysis and biodegradation (P&B), and biodegradation with nitrophenol (NP) and oxalic acid (OA) added individually and simultaneously (B + NP, B + OA, and B + NP + OA); NP and OA were NB’s main UV-photolysis products. Compared with B, the biodegradation rate P + B was lower by 13–29%, but intimately coupling (P&B) had a removal rate that was 10–13% higher; mineralization showed similar trends. B + OA gave results similar to P&B, B + NP gave results similar to P + B, and B + OA + NP gave results between P + B and P&B, depending on the amount of OA and NP added. The photolysis product OA accelerated NB biodegradation through a co-substrate effect, but NP was inhibitory. Although decreasing the UV photolysis time could minimize the inhibition impact of NP in P + B, P&B gave the fastest removal of NB by accentuating the co-substrate effect of OA

Radioluminescence of polyester resin modified with acrylic acid and its salts

Science.gov (United States)

Szalińska, H.; Wypych, M.; Pietrzak, M.; Szadkowska-Nicze, M.

Polimal-109 polyester resin and its compounds containing acrylic acid and its salts such as: sodium, potassium, magnesium, calcium, barium, iron, cobalt, copper and manganese acrylates were studied by the radioluminescence method, including isothermal luminescence (ITL) at a radiation temperature of 77 K, thermoluminescence (RTL) and spectral distributions of isothermal luminescence. Measurements of optical absorption at 77 K before and after irradiation of the investigated samples were also carried out. The results obtained have shown that metal ions play a significant part in the processes taking place in the polyester matrix under the influence of γ 60Co radiation.

Radioluminescence of polyester resin modified with acrylic acid and its salts

International Nuclear Information System (INIS)

Szalinska, H.; Wypych, M.; Pietrzak, M.; Szadkowska-Nicze, M.

1987-01-01

Polimal-109 polyester resin and its compounds containing acrylic acid and its salts such as: sodium, potassium, magnesium, calcium, barium, iron, cobalt, copper and manganese acrylates were studied by the radioluminescence method, including isothermal luminescence (ITL) at a radiation temperature of 77 K, thermoluminescence (RTL) and spectral distributions of isothermal luminescence. Measurements of optical absorption at 77K before and after irradiation of the investigated samples were also carried out. The results obtained have shown that metal ions play a significant part in the processes taking place in the polyester matrix under the influence of γ 60 Co radiation. (author)

Antifungal activity of fabrics knitted by metalized Silver/Polyester composite yarn

Science.gov (United States)

Özkan, İ.; Duru Baykal, P.

2017-10-01

In this study, antifungal properties of fabric knitted from metalized silver/polyester composite yarn were investigated. Intermingling is an alternative technique for yarn blending process. Yarns having different features can be combined by feeding the same intermingling jet. This process is defined as commingling. In the study, intermingling process was used to produce metalized silver/polyester composite yarn. Commingled yarns were knitted to single jersey fabrics by IPM brand sample type circular knitting machine. Antifungal activity test was applied to samples against Aspergillus Niger according to AATCC 30 test procedure. It has been identified that the application provides antifungal activity to fabric.

Photoinduced Circular Anisotropy in Side-Chain Azobenzene Polyesters

DEFF Research Database (Denmark)

Nikolova, L.; Todorov, T.; Ivanov, M.

1997-01-01

We report for the first time the inducing of large circular anisotropy in previously unoriented films of side-chain azobenzene polyesters on illumination with circularly polarized light at a wavelength of 488 nm. The circular dichroism and optical activity are measured simultaneously in real time...

Prevention of primary vascular graft infection with silver-coated polyester graft in a porcine model

DEFF Research Database (Denmark)

Gao, H; Sandermann, J; Prag, J

2010-01-01

To evaluate the efficacy of a silver-coated vascular polyester graft in the prevention of graft infection after inoculation with Staphylococcus aureus in a porcine model.......To evaluate the efficacy of a silver-coated vascular polyester graft in the prevention of graft infection after inoculation with Staphylococcus aureus in a porcine model....

Grey water biodegradability.

Science.gov (United States)

Ghunmi, Lina Abu; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

2011-02-01

Knowing the biodegradability characteristics of grey water constituents is imperative for a proper design and operation of a biological treatment system of grey water. This study characterizes the different COD fractions of dormitory grey water and investigates the effect of applying different conditions in the biodegradation test. The maximum aerobic and anaerobic biodegradability and conversion rate for the different COD fractions is determined. The results show that, on average, dormitory grey water COD fractions are 28% suspended, 32% colloidal and 40% dissolved. The studied factors incubation time, inoculum addition and temperature are influencing the determined biodegradability. The maximum biodegradability and biodegradation rate differ between different COD fractions, viz. COD(ss), COD(col) and COD(diss). The dissolved COD fraction is characterised by the lowest degradation rate, both for anaerobic and aerobic conditions. The maximum biodegradability for aerobic and anaerobic conditions is 86 and 70% respectively, whereas the first order conversion rate constant, k₂₀, is 0.119 and 0.005 day⁻¹, respectively. The anaerobic and aerobic conversion rates in relation to temperature can be described by the Arrhenius relation, with temperature coefficients of 1.069 and 1.099, respectively.

Protoenzymes: the case of hyperbranched polyesters

Science.gov (United States)

Mamajanov, Irena; Cody, George D.

2017-11-01

Enzymes are biopolymeric complexes that catalyse biochemical reactions and shape metabolic pathways. Enzymes usually work with small molecule cofactors that actively participate in reaction mechanisms and complex, usually globular, polymeric structures capable of specific substrate binding, encapsulation and orientation. Moreover, the globular structures of enzymes possess cavities with modulated microenvironments, facilitating the progression of reaction(s). The globular structure is ensured by long folded protein or RNA strands. Synthesis of such elaborate complexes has proven difficult under prebiotically plausible conditions. We explore here that catalysis may have been performed by alternative polymeric structures, namely hyperbranched polymers. Hyperbranched polymers are relatively complex structures that can be synthesized under prebiotically plausible conditions; their globular structure is ensured by virtue of their architecture rather than folding. In this study, we probe the ability of tertiary amine-bearing hyperbranched polyesters to form hydrophobic pockets as a reaction-promoting medium for the Kemp elimination reaction. Our results show that polyesters formed upon reaction between glycerol, triethanolamine and organic acid containing hydrophobic groups, i.e. adipic and methylsuccinic acid, are capable of increasing the rate of Kemp elimination by a factor of up to 3 over monomeric triethanolamine. This article is part of the themed issue 'Reconceptualizing the origins of life'.

Reactive modification of polyesters and their blends

Science.gov (United States)

Wan, Chen

2004-12-01

As part of a broader research effort to investigate the chemical modification of polyesters by reactive processing a low molecular weight (MW) unsaturated polyester (UP) and a higher MW saturated polyester, polyethylene terephthalate (PET), alone or blended with polypropylene (PP) were melt processed in a batch mixer and continuous twin screw extruders. Modification was monitored by on-line rheology and the products were characterized primarily by off-line rheology, morphology and thermal analysis. Efforts were made to establish processing/property relationships and provide an insight of the accompanying structural changes. The overall response of the reactively modified systems was found to be strongly dependent on the component characteristics, blend composition, type and concentrations of reactive additives and processing conditions. The work concluded that UP can be effectively modified through reactive melt processing. Its melt viscosity and MW can be increased through chemical reactions between organic peroxides (POX) and chain unsaturation or between MgO and carboxyl/hydroxyl end groups. Reactive blending of PP/UP blends through peroxide modification gave finer and more uniform morphology than unreacted blends and at a given PP/UP weight ratio more thermoplastic elastomers-like rheological behavior. This is due to the continuously decreasing viscosity ratio of PP/UP towards unity by the competing reactions between POX and the blend components and formation of PP-UP copolymers which serve as in-situ compatibilizers to promote better interfacial adhesion. Kinetics of the competing reactions were analyzed through a developed model. In addition to POX concentration and mixing efficiency, rheology and morphology of UP/PP bends were significantly affected by the addition of inorganic and organic coagents. Addition of coagents such as a difunctional maleimide, MgO and/or an anhydride functionalized PP during reactive blending offers effective means for tailoring

Quasi-static axial crushes on woven jute/polyester AA6063T52 composite tubes

Science.gov (United States)

Othman, A.; Ismail, AE

2018-04-01

Quasi-static axial loading have been studied in this paper to determine the behaviour of jute/polyester wrapped on aluminium alloy 6063T52. The filler material also was include into crush box specimen, which is polyurethane (PU) and polystyrene (PE) rigid foam at ranging 40 and 45 kg/m3 densities. All specimen profile was fabricated using hand layup techniques and the length of each specimen were fixed at 100 mm as well as diameter and width of the tube at 50.8 mm. The two types of tubular cross-section were studied of round and square thin-walled profiles and the angle of fibre at 450 were analysed for four layers. Thin walled of aluminium was 1.9 mm and end frontal of each specimen of composite were chamfered at 450 to prevent catastrophic failure mode. The specific absorbed energy (SEA) and crush force efficiency (CFE) were analyses for each specimen to see the behaviour on jute/polyester wrapped on metallic structure can give influence the energy management for automotive application. Result show that the four layers’ jute/polyester with filler material show significant value in term of specific absorbed energy compared empty and polyurethane profiles higher 26.66% for empty and 15.19% compared to polyurethane profiles. It has been found that the thin walled square profile of the jute/polyester tubes with polystyrene foam-filled is found higher respectively 27.42% to 13.13% than empty and polyurethane (PU) foam tubes. An introduce filler material onto thin walled composite profiles gave major advantage increases the mean axial load of 31.87% from 32.94 kN to 48.35 kN from empty to polystyrene thin walled round jute/polyester profiles and 31.7% from 23.11 KN to 33.84 kN from empty to polystyrene thin walled square jute/polyester profiles. Failure mechanisms of the axially loaded composite tubes were also observed and discussed.

High-performance biodegradable polylactide composites fabricated using a novel plasticizer and functionalized eggshell powder.

Science.gov (United States)

Kong, Junjun; Li, Yi; Bai, Yungang; Li, Zonglin; Cao, Zengwen; Yu, Yancun; Han, Changyu; Dong, Lisong

2018-06-01

A novel polyester poly(diethylene glycol succinate) (PDEGS) was synthesized and evaluated as a plasticizer for polylactide (PLA) in this study. Meanwhile, an effective sustainable filler, functionalized eggshell powder (FES) with a surface layer of calcium phenyphosphonate was also prepared. Then, PLA biocomposites were prepared from FES and PDEGS using a facile melt blending process. The addition of 15 wt% PDEGS as plasticizer showed good miscibility with PLA macromolecules and increased the chain mobility of PLA. The crystallization kinetics of PLA composites revealed that the highly effective nucleating FES significantly improved the crystallization ability of PLA at both of non-isothermal and isothermal conditions. In addition, the effective plasticizer and well-dispersed FES increased the elongation at break from 6% of pure PLA to over 200% for all of the plasticized PLA composites. These biodegradable PLA biocomposites, coupled with excellent crystallization ability and tunable mechanical properties, demonstrate their potential as alternatives to traditional commodity plastics. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of nanomodified polyester resin on hybrid sandwich laminates

International Nuclear Information System (INIS)

Anbusagar, NRR.; Giridharan, P.K.; Palanikumar, K.

2014-01-01

Highlights: • Effect of nanomodified polyester resin on hybrid sandwich laminates is evaluated. • The hybrid sandwich laminates are fabricated with varying wt% of nanoclay. • Flexural, impact and moisture absorbtion properties are evaluated for hybrid composites. • Scanning electron microscopy is utilized to analyze the dispersion of clay and fractured surfaces of the nanocomposites. - Abstract: Effect of nanoclay modified polyester resin on flexural, impact, hardness and water absorption properties of untreated woven jute and glass fabric hybrid sandwich laminates have been investigated experimentally. The hybrid sandwich laminates are prepared by hand lay-up manufacturing technique (HL) for investigation. All hybrid sandwich laminates are fabricated with a total of 10 layers, by varying the extreme layers and wt% of nanoclay in polyester resin so as to obtain four different combinations of hybrid sandwich laminates. For comparison of the composite with hybrid composite, jute fiber reinforced composite laminate also fabricated. X-ray diffraction (XRD) results obtained from samples with nanoclay indicated that intergallery spacing of the layered clay increases with matrix. Scanning electron microscopy (SEM) gave a morphological picture of the cross-sections and energy dispersive X-ray spectroscopy (EDS) allowed investigating the elemental composition of matrix in composites. The testing results indicated that the flexural properties are greatly increased at 4% of nanoclay loading while impact, hardness and water absorption properties are increased at 6% of nanoclay loading. A plausible explanation for high increase of properties has also been discussed

Hydrolytic And Enzymatic Degradation Characteristics Of Biodegradable Aliphatic Polysters

Institute of Scientific and Technical Information of China (English)

LI Suming

2004-01-01

Aliphatic polyesters, especially those derived from lactide (PLA), glycolide (PGA) and ε-caprolactone (PCL), are being investigated worldwide for applications in the field of surgery (suture material, devices for internal bone fracture fixation), pharmacology (sustained drug delivery systems), and tissue engineering (scaffold for tissue regeneration) [1,2]. This is mainly due to their good biocompatibility and variable degradability. These polymers present also a growing interest for environmental applications in agriculture (mulch films) and in our everyday life (packaging material)as the development of biodegradable materials is now considered as one of the potential solutions to the problem of plastic waste management.For both biomedical and environmental applications, it is of major importance to understand the degradation characteristics of the polymers. The hydrolytic degradation of aliphatic polyesters has been investigated by many research groups. Our group has shown that degradation of PLAGA large size devices is faster inside than at the surface. This heterogeneous degradation is due to the autocatalytic effect of carboxylic endgroups formed by ester bond cleavage. Moreover,degradation-induced morphological and compositional changes were also elucidated. In the case of PCL, the hydrolytic degradation is very slow due to its hydrophobicity and crystallinity.The enzymatic degradation of these polymers has been investigated by a number of authors. A specific enzyme, proteinase K, has been shown to have significant effects on PLA degradation. This enzyme preferentially degrade L-lactate units as opposed to D-lactate ones, amorphous zones as opposed to crystalline ones [3]. The enzymatic degradation of PCL polymers has also been investigated. A number of lipase-type enzymes were found to significantly accelerate the degradation of PCL despite its high crystallinity. In the case of PLA/PCL blends, the two components exhibited well separated crystalline domains

Corona Glow Discharge Plasma Treatment for Hidrophylicity Improvement of Polyester and Cotton Fabrics

Science.gov (United States)

Susan, A. I.; Widodo, M.; Nur, M.

2017-07-01

The effects of irradiation by a corona glow discharge plasma on hidrophylicity properties of polyester and cotton fabrics were investigated. We used a corona glow discharge plasma reactor with multiple points to plane electrodes, which was generated by a high voltage DC. Factors that affect the hidrophylicity properties were identified and evaluated as functions of irradiation parameters, which include duration of treatment, distance between electrodes, and bias voltage. It was readily observed from SEM examinations that plasma changed the surface morphology of both polyester and cotton fibers, giving result to an increased roughness to both of them. Results also showed that the hidrophylicityof polyester and cotton fabrics improved by the treatment, which is proportional to the time of treatment and voltage, but inversely proportional to the distance between electrodes. Time of treatment that provided the optimum enhancement of hidrophylicity for cotton is 15 minutes which improved the wetting time from 8.16 seconds to 1.26 seconds. For polyester, it took 15 minutes of irradiation time to improve the wetting time from 7340 seconds to 2905 seconds. The optimum distance between electrodes for both fabrics in this study was found to be 2 cm. Further analysis showed that the improved hidrophylicity properties is due to the creation of surface radicals by free radicals in the plasma leading to the formation of new water-attracting functional groups on the fiber surface.

Novel organometallic aromatic polyester based on ferrocene

Institute of Scientific and Technical Information of China (English)

Wei

2010-01-01

A novel polyester containing ferrocenyl was prepared by low-temperature interface polycondensation of 1,1'-ferrocenedi-carboxylic acid chloride with 4-(4-hydroxyphenyl)-2,3-phthalazin-l-one(DHPZ), which is a twisted non-coplanar heterocyclic bisphenol-like monomer. The newly generated polymer was evaluated based on characterization of its solubility, viscosity measurements, elemental analysis, FTIR spectroscopy, differential scanning calorimetric and thermogravimetric studies.

Sulfonation of polyester fabrics by gaseous sulfur oxide activated by UV irradiation

International Nuclear Information System (INIS)

Kordoghli, Bessem; Khiari, Ramzi; Mhenni, Mohamed Farouk; Sakli, Faouzi; Belgacem, Mohamed Naceur

2012-01-01

Highlights: ► In this paper, an original technique was present to improve the hydrophilic properties of polyester fibres. ► The modification of PET fabric was carried out using gaseous sulfur trioxide activated by UV irradiations. ► We fully characterized the modified and untreated fabrics. - Abstract: This paper describes an original technique aiming to improve the hydrophilic properties of polyester fibres. In this method, the sulfonation of the aromatic rings is carried out using gaseous sulfur trioxide activated by UV irradiations. Thus, exposing the polyester textile fabric to the UVC light (wavelength around 254 nm) under a stream of sulfur trioxide leads to the fixation of -SO 3 H groups. The amounts of the fixed sulfonate groups depended on the reaction conditions. Evidence of grafting deduced from the measurements of hygroscopic properties was carried out by contact angle measurement, moisture regain as well as by measuring the rate of retention. SEM and FT-IR analysis, DSC and DTA/TGA thermograms showed that no significant modifications have occurred in the bulk of the treated PET fabrics.

Soil-release behaviour of polyester fabrics after chemical modification with polyethylene glycol

Science.gov (United States)

Miranda, T. M. R.; Santos, J.; Soares, G. M. B.

2017-10-01

The fibres cleanability depends, among other characteristics, on their hydrophilicity. Hydrophilic fibres are easy-wash materials but hydrophobic fibres are difficult to clean due to their higher water-repellent surfaces. This type of surfaces, like polyester (PET), produce an accumulation of electrostatic charges, which favors adsorption and retention of dirt. Thus, the polyester soil-release properties can be increased by finishing processes that improve fiber hydrophilicity. In present study, PET fabric modification was described by using poly(ethylene glycol) (PEG) and N,N´-dimethylol-4,5-dihydroxyethylene urea (DMDHEU) chemically modified resin. Briefly, the modification process was carried out in two steps, one to hydrolyse the polyester and create hydroxyl and carboxylic acid groups on the surface and other to crosslink the PEG chains. The resulting materials were characterized by contact angle, DSC and FTIR-ATR methods. Additionally, the soil release behavior and the mechanical properties of modified PET were evaluated. For the best process conditions, the treated PET presented 0° contact angle, grade 5 stain release and acceptable mechanical performance.

Thread angle dependency on flame spread shape over kenaf/polyester combined fabric

Science.gov (United States)

Azahari Razali, Mohd; Sapit, Azwan; Nizam Mohammed, Akmal; Nor Anuar Mohamad, Md; Nordin, Normayati; Sadikin, Azmahani; Faisal Hushim, Mohd; Jaat, Norrizam; Khalid, Amir

2017-09-01

Understanding flame spread behavior is crucial to Fire Safety Engineering. It is noted that the natural fiber exhibits different flame spread behavior than the one of the synthetic fiber. This different may influences the flame spread behavior over combined fabric. There is a research has been done to examined the flame spread behavior over kenaf/polyester fabric. It is seen that the flame spread shape is dependent on the thread angle dependency. However, the explanation of this phenomenon is not described in detail in that research. In this study, explanation about this phenomenon is given in detail. Results show that the flame spread shape is dependent on the position of synthetic thread. For thread angle, θ = 0°, the polyester thread is breaking when the flame approach to the thread and the kenaf thread tends to move to the breaking direction. This behavior produces flame to be ‘V’ shape. However, for thread angle, θ = 90°, the polyester thread melts while the kenaf thread decomposed and burned. At this angle, the distance between kenaf threads remains constant as flame approaches.

Dsc cure kinetics of an unsaturated polyester resin using empirical kinetic model

International Nuclear Information System (INIS)

Abdullah, I.

2015-01-01

In this paper, the kinetics of curing of unsaturated polyester resin initiated with benzoyl peroxide was studied. In case of unsaturated polyester (UP) resin, isothermal test alone could not predict correctly the curing time of UP resin. Therefore, isothermal kinetic analysis through isoconventional adjustment was used to correctly predict the curing time and temperature of UP resin. Isothermal kinetic analysis through isoconversional adjustment indicated that 97% of UP resin cures in 33 min at 120 degree C. Curing of UP resin through microwaves was also studied and found that 67% of UP resin cures in 1 min at 120 degree C. The crosslinking reaction of UP resin is so fast at 120 degree C that it becomes impossible to predict correctly the curing time of UP resin using isothermal test and the burial of C=C bonds in microgels makes it impossible to be fully cured by microwaves at 120 degree C. The rheological behaviour of unsaturated polyester resin was also studied to observe the change in viscosity with respect to time and temperature. (author)

Effect of chemical heterogeneity of biodegradable polymers on surface energy: A static contact angle analysis of polyester model films

Energy Technology Data Exchange (ETDEWEB)

Belibel, R.; Avramoglou, T. [INSERM U1148, Laboratory for Vascular Translational Science (LVTS), Institut Galilée, Université Paris 13, Sorbonne Paris Cité, 99 Avenue Jean-Baptiste Clément, Villetaneuse F-93430 (France); Garcia, A. [CNRS UPR 3407, Laboratoire des Sciences des Procédés et des Matériau, Institut Galilée, Université Paris 13, Sorbonne Paris Cité, 99 Avenue Jean-Baptiste Clément, Villetaneuse F-93430 (France); Barbaud, C. [INSERM U1148, Laboratory for Vascular Translational Science (LVTS), Institut Galilée, Université Paris 13, Sorbonne Paris Cité, 99 Avenue Jean-Baptiste Clément, Villetaneuse F-93430 (France); Mora, L., E-mail: Laurence.mora@univ-paris13.fr [INSERM U1148, Laboratory for Vascular Translational Science (LVTS), Institut Galilée, Université Paris 13, Sorbonne Paris Cité, 99 Avenue Jean-Baptiste Clément, Villetaneuse F-93430 (France)

2016-02-01

Biodegradable and bioassimilable poly((R,S)-3,3 dimethylmalic acid) (PDMMLA) derivatives were synthesized and characterized in order to develop a new coating for coronary endoprosthesis enabling the reduction of restenosis. The PDMMLA was chemically modified to form different custom groups in its side chain. Three side groups were chosen: the hexyl group for its hydrophobic nature, the carboxylic acid and alcohol groups for their acid and neutral hydrophilic character, respectively. The sessile drop method was applied to characterize the wettability of biodegradable polymer film coatings. Surface energy and components were calculated. The van Oss approach helped reach not only the dispersive and polar acid–base components of surface energy but also acid and basic components. Surface topography was quantified by atomic force microscopy (AFM) and subnanometer average values of roughness (Ra) were obtained for all the analyzed surfaces. Thus, roughness was considered to have a negligible effect on wettability measurements. In contrast, heterogeneous surfaces had to be corrected by the Cassie–Baxter equation for copolymers (10/90, 20/80 and 30/70). The impact of this correction was quantified for all the wettability parameters. Very high relative corrections (%) were found, reaching 100% for energies and 30% for contact angles. - Highlights: • We develop different polymers with various chemical compositions. • Wettability properties were calculated using Cassie corrected contact angles. • Percentage of acid groups in polymers is directly correlated to acid part of SFE. • Cassie corrections are necessary for heterogeneous polymers.

Biodegradable plastics from Sinorhizobium meliloti as plastics compatible with the environment and human health

Directory of Open Access Journals (Sweden)

Mehrdad Hashemi Beidokhti

2016-03-01

Full Text Available Introduction: Polyhydroxyalkanoates (PHAs are natural polyesters and biodegradable plastics that are stored as intracellular inclusion bodies by a great variety of bacteria. The aim of this study was to extract polyhydroxyalkanoate from native Sinorhizobium meliloti in Iran. Materials and methods: Sinorhizobium meliloti isolates were collected from roots of alfalfa plants and were identified by Gram staining, biochemical experiments and amplification of 1500 bp fragment of 16Sr DNA gene. PHA granules were detected by microscopic examination. PHA production was evaluated in nutrient deficient medium and its amount was determined by conversion of PHA into crotonic acid by sulphuric acid treatment. The effect of various temperatures, agitation rate and carbon source (sucrose, mannitol, and maltose were evaluated on dry cell weight and polyhydroxybutyrate (PHB production. Results: The maximum amount of polymer production (43.10% was seen in basal mineral medium at 29°C, pH~7 and 215 revolutions per minute (rpm. The results of this research showed that the S5 isolate was capable to produce maximum poly3- hydroxybutyrate. The produced polymer was analyzed for its purity by GC- mass (gas chromatography- mass spectroscopy and confirmed to be PHB compared with the standard polymer. Discussion and conclusion: Native strains of Sinorhizobium can be used in the production of biodegradable plastics and the results of present study showed that S. meliloti S5 was capable to produce maximum PHB at 29°C, agitation rate of 215 rpm, and pH~7. 

The Degradation of Mechanical Properties in Halloysite Nano clay-Polyester Nano composites Exposed in Seawater Environment

International Nuclear Information System (INIS)

Saharudin, M.S.; Saharudin, M. Sh.; Wei, J.; Shyha, I.; Inam, F.

2016-01-01

Polyester based polymers are extensively used in aggressive marine environments; however, inadequate data is available on the effects of the seawater on the polyester based nano composites mechanical properties. This paper reports the effect of seawater absorption on the mechanical properties degradation of halloysite nano clay-polyester nano composites. Results confirmed that the addition of halloysite nano clay into polyester matrix was found to increase seawater uptake and reduce mechanical properties compared to monolithic polyester. The maximum decreases in microhardness, tensile and flexural properties, and impact toughness were observed in case of 1 wt% nano clay. The microhardness decreased from 107 HV to 41.7 HV (61% decrease). Young s modulus decreased from 0.6 GPa to 0.4 GPa (33% decrease). The flexural modulus decreased from 0.6 GPa to 0.34 GPa (43% decrease). The impact toughness dropped from 0.71 kJ/m"2 to 0.48 kJ/m"2 (32% decrease). Interestingly, the fracture toughnessκ_1C increased with the addition of halloysite nano clay due to the plasticization effect of the resin matrix. SEM images revealed the significant reduction in mechanical properties in case of 1 wt% reinforcement which is attributed to the degradation of the nano clay-matrix interface influenced by seawater absorption and agglomeration of halloysite nano clay.

Surface modification of polyester fabrics by atmospheric-pressure air/He plasma for color strength and adhesion enhancement

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chunming, E-mail: zcm1229@126.com [College of Textiles and Clothing, Qingdao University, Qingdao 266071 (China); Sunvim Grp Co Ltd, Gaomi 261500 (China); Zhao, Meihua; Wang, Libing; Qu, Lijun [College of Textiles and Clothing, Qingdao University, Qingdao 266071 (China); Men, Yajing [Sunvim Grp Co Ltd, Gaomi 261500 (China)

2017-04-01

Highlights: • Air/He plasma gave hydrophilicity on polyester surface and decreased contact angle to 18°. • The roughness of polyester increased and pit-like structures appeared on the surface after plasma treatment. • XPS confirmed the generation of new functional groups on polyester fabric. • The improved pigment color yield and anti-bleeding performance were contributed by the alteration of pigment adhesion. • The air/He plasma was more effective than air plasma at the same treatment time. - Abstract: Surface properties of water-based pigmented inks for ink-jet printed polyester fabrics were modified with atmospheric-pressure air/He plasma to improve the color strength and pigment adhesion of the treated surfaces. The influence of various parameters, including the surface morphology, chemical compositions, surface energy and dynamic contact angles of the control and plasma treated samples was studied. Color strength and edge definition were used to evaluate the ink-jet printing performance of fabrics. The change in pigment adhesion to polyester fibers was analyzed by SEM (scanning electron microscopy). AFM (Atomic force microscope) and XPS (X-ray photoelectron spectroscopy) analyses indicated the increase in surface roughness and the oxygen-containing polar groups(C=O, C−OH and COOH) reinforced the fixation of pigments on the fiber surface. The result from this study suggested that the improved pigment color yield was clearly affected by alteration of pigment adhesion enhanced by plasma surface modification. Polyester fabrics exhibited better surface property and ink-jet printing performance after the air/He mixture plasma treatment comparing with those after air plasma treatment.

Surface modification of polyester fabrics by atmospheric-pressure air/He plasma for color strength and adhesion enhancement

International Nuclear Information System (INIS)

Zhang, Chunming; Zhao, Meihua; Wang, Libing; Qu, Lijun; Men, Yajing

2017-01-01

Highlights: • Air/He plasma gave hydrophilicity on polyester surface and decreased contact angle to 18°. • The roughness of polyester increased and pit-like structures appeared on the surface after plasma treatment. • XPS confirmed the generation of new functional groups on polyester fabric. • The improved pigment color yield and anti-bleeding performance were contributed by the alteration of pigment adhesion. • The air/He plasma was more effective than air plasma at the same treatment time. - Abstract: Surface properties of water-based pigmented inks for ink-jet printed polyester fabrics were modified with atmospheric-pressure air/He plasma to improve the color strength and pigment adhesion of the treated surfaces. The influence of various parameters, including the surface morphology, chemical compositions, surface energy and dynamic contact angles of the control and plasma treated samples was studied. Color strength and edge definition were used to evaluate the ink-jet printing performance of fabrics. The change in pigment adhesion to polyester fibers was analyzed by SEM (scanning electron microscopy). AFM (Atomic force microscope) and XPS (X-ray photoelectron spectroscopy) analyses indicated the increase in surface roughness and the oxygen-containing polar groups(C=O, C−OH and COOH) reinforced the fixation of pigments on the fiber surface. The result from this study suggested that the improved pigment color yield was clearly affected by alteration of pigment adhesion enhanced by plasma surface modification. Polyester fabrics exhibited better surface property and ink-jet printing performance after the air/He mixture plasma treatment comparing with those after air plasma treatment.

Biodegradability of plastics.

Science.gov (United States)

Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

2009-08-26

Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

Salicylaldimine Copper(II) complex catalyst: Pioneer for ring ...

Indian Academy of Sciences (India)

leading biodegradable and biocompatible polyester and. PLA degrades to form nontoxic components (water ... in surgery as orthopedic applications, tissue engineer- ing and biodegradable internal fixation devices.8,9 ..... In Polymers of Lactic Acid D P Mobley (Ed.) In Plastics from Microbes (Munchen, Germany: Hanser ...

Self-Assembled Cationic Biodegradable Nanoparticles from pH-Responsive Amino-Acid-Based Poly(Ester Urea Urethane)s and Their Application As a Drug Delivery Vehicle.

Science.gov (United States)

He, Mingyu; Potuck, Alicia; Kohn, Julie C; Fung, Katharina; Reinhart-King, Cynthia A; Chu, Chih-Chang

2016-02-08

The objective of this study is to develop a new family of biodegradable and biologically active copolymers and their subsequent self-assembled cationic nanoparticles as better delivery vehicles for anticancer drugs to achieve the synergism between the cytotoxicity effects of the loaded drugs and the macrophage inflammatory response of the delivery vehicle. This family of cationic nanoparticles was formulated from a new family of amphiphilic cationic Arginine-Leucine (Arg-Leu)-based poly(ester urea urethane) (Arg-Leu PEUU) synthesized from four building blocks (amino acids, diols, glycerol α-monoallyl ether, and 1,6 hexamethylene diisocyanate). The chemical, physical, and biological properties of Arg-Leu PEUU biomaterials can be tuned by controlling the feed ratio of the four building blocks. The Arg-Leu PEUU copolymers have weight-average molecular weights from 13.4 to 16.8 kDa and glass-transition temperatures from -3.4 to -4.6 °C. The self-assembled cationic nanoparticles (Arg-Leu PEUU NPs) were prepared using a facile dialysis method. Arg-Leu PEUU NPs have average diameters ranging from 187 to 272 nm, show good biocompatibility with 3T3 fibroblasts, and they support bovine aortic endothelial cell (BAEC) proliferation and adhesion. Arg-Leu PEUU NPs also enhanced the macrophages' production of tumor necrosis factor-α (TNF-α) and nitric oxide (NO), but produced relatively low levels of interleukin-10 (IL-10), and therefore, the antitumor activity of macrophages might be enhanced. Arg-Leu PEUU NPs were taken up by HeLa cells after 4 h of incubation. The in vitro hemolysis assay showed the cationic Arg-Leu PEUU NPs increased their chance of endosomal escape at a more acidic pH. Doxorubicin (DOX) was successfully incorporated into the Arg-Leu PEUU NPs, and the DOX-loaded Arg-Leu PEUU NPs exhibited a pH-dependent drug release profile with accelerated release kinetics in a mild acidic condition. The DOX-loaded 6-Arg-4-Leu-4 A/L-2/1 NPs showed higher HeLa cell

Dyeing of Polyester with Disperse Dyes: Part 2. Synthesis and Dyeing Characteristics of Some Azo Disperse Dyes for Polyester Fabrics

Directory of Open Access Journals (Sweden)

Alya M. Al-Etaibi

2016-06-01

Full Text Available The goal of this study was to utilize carrier for accelerating the rate of dyeing not only to enhance dyeing of polyester fabrics dyed with disperse dyes 3a,b, but also to save energy. Both the color strength expressed as dye uptake and the fastness properties of the dyed fabrics were evaluated.

Generation of Microcellular Biodegradable Polycaprolactone Foams in Supercritical Carbon Dioxide

Institute of Scientific and Technical Information of China (English)

Xu Qun; Ren Xian-wen; Chang Yu-ning; Yu Long; Wang Jing-wu

2004-01-01

Present now the application of microcellular polymeric materials in biomedical field is growing rapidly, as that of guided tissue regeneration and cell transplantation. As far as guided tissue regeneration is concerned, porous implants are used as size selective membrane to promote the growth of a special tissue in a healing site. Ideally, the implant should be inherently biocompatible,have well-defined cell size and be resorbable with appropriate biodegradation rates.Poly(a-caprolactone) (PCL) is a kind of materials suit for the demands above. PCL is biocompatible and biodegradable aliphatic polyester which is nontoxic for living organisms and bioresorbable after a period of implantation. Because of its unique combination of biocompatibility, permeability and biodegradability, PCL and some of its copolymer with lactides and glycolide have been widely applied in medicine as artificial skin, artificial bone and containers for sustained drug release.Goel and Beckman have reported a new method to generate microcellular poly(methy l methacrylate) foams in which the samples are saturated with CO2 under a series of supercritical (SC)conditions, and then the system is rapidly depressurized to atmospheric pressure at constant temperature. Unlike traditional methods, it reduces glass-transition temperature (Tg) of the mixture to below the experimental temperature rather than directly heat the system above Tg. In this process of nucleation, no phase separation occurs as well as no phase boundary meets, so the cellular structure of the foam can be retained better.In this work, we have generated PCL foams by using supercritical CO2. Because of the low glass transition temperature (Tg = -60 ℃) of PCL far below the ice point, the experimental temperature in our study is much higher than Tg, which is different from the studies by others before. A series of variable factors on the foam structure as saturation temperature, saturation pressure, saturation time and depressurization

Biodegradability of Plastics

Directory of Open Access Journals (Sweden)

Yutaka Tokiwa

2009-08-01

Full Text Available Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.. In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

Anaerobic biodegradability of macropollutants

DEFF Research Database (Denmark)

Angelidaki, Irini

2002-01-01

A variety of test procedures for determination of anaerobic biodegradability has been reported. This paper reviews the methods developed for determination of anaerobic biodegradability of macro-pollutants. Anaerobic biodegradability of micro-pollutants is not included. Furthermore, factors...

Modification of unsaturated polyester resins using nano-size core ...

African Journals Online (AJOL)

Modification of unsaturated polyester resins using nano-size core-shell particles. MO Munyati, PA Lovell. Abstract. No Abstract Available Journal of Science and Technology Special Edition 2004: 24-31. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

Synthesis of polyester urethane urea and fabrication of elastomeric nanofibrous scaffolds for myocardial regeneration

Energy Technology Data Exchange (ETDEWEB)

Jamadi, Elham Sadat; Ghasemi-Mobarakeh, Laleh [Department of Textile engineering, Isfahan university of technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Morshed, Mohammad, E-mail: morshed@cc.iut.ac.ir [Department of Textile engineering, Isfahan university of technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Sadeghi, Morteza [Department of Chemical Engineering, Isfahan university of technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Prabhakaran, Molamma P., E-mail: nanotechmpp@gmail.com [Department of Mechanical Engineering, Faculty of Engineering, 2 Engineering Drive 3, National University of Singapore, Singapore 117576 (Singapore); Ramakrishna, Seeram [Department of Mechanical Engineering, Faculty of Engineering, 2 Engineering Drive 3, National University of Singapore, Singapore 117576 (Singapore)

2016-06-01

Fabrication of bioactive scaffolds is one of the most promising strategies to reconstruct the infarcted myocardium. In this study, we synthesized polyester urethane urea (PEUU), further blended it with gelatin and fabricated PEUU/G nanofibrous scaffolds. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and X-ray diffraction were used for the characterization of the synthesized PEUU and properties of nanofibrous scaffolds were evaluated using scanning electron microscopy (SEM), ATR-FTIR, contact angle measurement, biodegradation test, tensile strength analysis and dynamic mechanical analysis (DMA). In vitro biocompatibility studies were performed using cardiomyocytes. DMA analysis showed that the scaffolds could be reshaped with cyclic deformations and might remain stable in the frequencies of the physiological activity of the heart. On the whole, our study suggests that aligned PEUU/G 70:30 nanofibrous scaffolds meet the required specifications for cardiac tissue engineering and could be used as a promising construct for myocardial regeneration. - Highlights: • PEUU was synthesized to fabricate elastomeric scaffolds for myocardial regeneration. • FTIR, DSC and XRD analysis showed that polymer synthesis was well. • PEUU/gelatin nanofibrous scaffolds could be reshaped with cyclic deformations of the heart. • Gelatin in structure of PEUU nanofibers improved proliferation of cardiomyocytes. • Aligned PEUU/gelatin 70:30 nanofibrous scaffold support the alignment of cardiomyocytes.

Biodegradation and bioremediation

DEFF Research Database (Denmark)

Albrechtsen, H.-J.

1996-01-01

Anmeldelse af Alexander,M.: Biodegradation and bioremediation. Academic Press, Sandiego, USA, 1994......Anmeldelse af Alexander,M.: Biodegradation and bioremediation. Academic Press, Sandiego, USA, 1994...

Sulfonation of polyester fabrics by gaseous sulfur oxide activated by UV irradiation

Energy Technology Data Exchange (ETDEWEB)

Kordoghli, Bessem [Laboratory of Applied Chemical and Environment (UR-CAE) - University of Monastir (Tunisia); Textile Research Laboratory (LRT) - ISET Kasr Hellal, University of Monastir (Tunisia); Khiari, Ramzi, E-mail: khiari_ramzi2000@yahoo.fr [Laboratory of Applied Chemical and Environment (UR-CAE) - University of Monastir (Tunisia); LGP2 - Laboratory of Pulp and Paper Science, 461, Rue de la Papeterie - BP 65, 38402 Saint Martin d' Heres Cedex (France); Mhenni, Mohamed Farouk [Laboratory of Applied Chemical and Environment (UR-CAE) - University of Monastir (Tunisia); Sakli, Faouzi [Textile Research Laboratory (LRT) - ISET Kasr Hellal, University of Monastir (Tunisia); Belgacem, Mohamed Naceur [LGP2 - Laboratory of Pulp and Paper Science, 461, Rue de la Papeterie - BP 65, 38402 Saint Martin d' Heres Cedex (France)

2012-10-01

Highlights: Black-Right-Pointing-Pointer In this paper, an original technique was present to improve the hydrophilic properties of polyester fibres. Black-Right-Pointing-Pointer The modification of PET fabric was carried out using gaseous sulfur trioxide activated by UV irradiations. Black-Right-Pointing-Pointer We fully characterized the modified and untreated fabrics. - Abstract: This paper describes an original technique aiming to improve the hydrophilic properties of polyester fibres. In this method, the sulfonation of the aromatic rings is carried out using gaseous sulfur trioxide activated by UV irradiations. Thus, exposing the polyester textile fabric to the UVC light (wavelength around 254 nm) under a stream of sulfur trioxide leads to the fixation of -SO{sub 3}H groups. The amounts of the fixed sulfonate groups depended on the reaction conditions. Evidence of grafting deduced from the measurements of hygroscopic properties was carried out by contact angle measurement, moisture regain as well as by measuring the rate of retention. SEM and FT-IR analysis, DSC and DTA/TGA thermograms showed that no significant modifications have occurred in the bulk of the treated PET fabrics.

A novel polyester composite nanofiltration membrane formed by interfacial polymerization of pentaerythritol (PE) and trimesoyl chloride (TMC)

Science.gov (United States)

Cheng, Jun; Shi, Wenxin; Zhang, Lanhe; Zhang, Ruijun

2017-09-01

A novel polyester thin film composite nanofiltration (NF) membrane was prepared by interfacial polymerization of pentaerythritol (PE) and trimesoyl chloride (TMC) on polyethersulfone (PES) supporting membrane. The performance of the polyester composite NF membrane was optimized by regulating the preparation parameters, including reaction time, pH of the aqueous phase solution, pentaerythritol concentration and TMC concentration. A series of characterization, including permeation experiments, attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscope (SEM), atomic force microscopy (AFM), zeta potential analyzer and chlorine resistance experiments, were employed to study the properties of the optimized membrane. The results showed that the optimized polyester composite NF membrane exhibited very high rejection of Na2SO4 (98.1%), but the water flux is relatively low (6.1 L/m2 h, 0.5 MPa, 25 °C). The order of salt rejections is Na2SO4 > MgSO4 > MgCl2 > NaCl, which indicated the membrane was negatively charged, just consistent with the membrane zeta potential results. After treating by NaClO solutions with different concentrations (100 ppm, 500 ppm, 1000 ppm, 2000 ppm, 3000 ppm) for 48 h, the results demonstrated that the polyester NF membrane had good chlorine resistance. Additionally, the polyester TFC NF membrane exhibits good long-term stability.

Purification and Properties of a Polyester Polyurethane-Degrading Enzyme from Comamonas acidovorans TB-35

OpenAIRE

Akutsu, Yukie; Nakajima-Kambe, Toshiaki; Nomura, Nobuhiko; Nakahara, Tadaatsu

1998-01-01

A polyester polyurethane (PUR)-degrading enzyme, PUR esterase, derived from Comamonas acidovorans TB-35, a bacterium that utilizes polyester PUR as the sole carbon source, was purified until it showed a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This enzyme was bound to the cell surface and was extracted by addition of 0.2% N,N-bis(3-d-gluconamidopropyl)deoxycholamide (deoxy-BIGCHAP). The results of gel filtration and SDS-PAGE showed that the PUR este...

Impact behaviour of Napier/polyester composites under different energy levels

Energy Technology Data Exchange (ETDEWEB)

Fahmi, I., E-mail: fahmi-unimap@yahoo.com; Majid, M. S. Abdul, E-mail: shukry@unimap.edu.my; Afendi, M., E-mail: afendirojan@unimap.edu.my; Haameem, J. M.A., E-mail: mhaameem@gmail.com [School of Mechatronic Engineering, Universiti Malaysia Perlis, Arau (Malaysia); Haslan, M., E-mail: haslan@sirim.my; Helmi, E. A., E-mail: hilmi@sirim.my [Advanced Material Research Centre (AMREC), SIRIM Berhad, Kulim (Malaysia)

2016-07-19

The effects of different energy levels on the impact behaviour of Napier fibre/polyester reinforced composites were investigated. Napier fibre was extracted using traditional water retting process to be utilized as reinforcing materials in polyester composite laminates. 25% fibre loading composite laminates were prepared and impacted at three different energy levels; 2.5,5 and 7.5 J using an instrumented drop weight impact testing machine (IMATEK IM10). The outcomes show that peak force and contact time increase with increased impact load. The energy absorption was then calculated from the force displacement curve. The results indicated that the energy absorption decreases with increasing energy levels of the impact. Impacted specimens were observed visually for fragmentation fracture using an optical camera to identify the failure mechanisms. Fracture fragmentation pattern from permanent dent to perforation with radial and circumferential was observed.

Tensile strength of woven yarn kenaf fiber reinforced polyester composites

Directory of Open Access Journals (Sweden)

A.E. Ismail

2015-12-01

Full Text Available This paper presents the tensile strength of woven kenaf fiber reinforced polyester composites. The as-received yarn kenaf fiber is weaved and then aligned into specific fiber orientations before it is hardened with polyester resin. The composite plates are shaped according to the standard geometry and uni-axially loaded in order to investigate the tensile responses. Two important parameters are studied such as fiber orientations and number of layers. According to the results, it is shown that fiber orientations greatly affected the ultimate tensile strength but it is not for modulus of elasticity for both types of layers. It is estimated that the reductions of both ultimate tensile strength and Young’s modulus are in the range of 27.7-30.9% and 2.4-3.7% respectively, if the inclined fibers are used with respect to the principal axis.

Fabrication of narrow surface relief features in a side-chain azobenzene polyester with a scanning near-field microscope

DEFF Research Database (Denmark)

Ramanujam, P.S.; Holme, N. C. R.; Pedersen, M.

2001-01-01

We show that it is possible to fabricate topographic submicron features in a side-chain azobenzene polyester with a scanning near-field optical microscope, Through irradiation at a wavelength of 488 run at intensity levels of 12 W/cm(2), topographic features as narrow as 240 nm and as high as 6 nm...... have been reproducibly recorded in a thin film of the polyester. These observations are consistent with the fact that at low intensities peaks are produced evolving into formation of trenches at high intensities in the case of amorphous side-chain azobenzene polyesters. This may find applications...

Influence of Immersion Conditions on The Tensile Strength of Recycled Kevlar®/Polyester/Low-Melting-Point Polyester Nonwoven Geotextiles through Applying Statistical Analyses

Directory of Open Access Journals (Sweden)

Jing-Chzi Hsieh

2016-05-01

Full Text Available The recycled Kevlar®/polyester/low-melting-point polyester (recycled Kevlar®/PET/LPET nonwoven geotextiles are immersed in neutral, strong acid, and strong alkali solutions, respectively, at different temperatures for four months. Their tensile strength is then tested according to various immersion periods at various temperatures, in order to determine their durability to chemicals. For the purpose of analyzing the possible factors that influence mechanical properties of geotextiles under diverse environmental conditions, the experimental results and statistical analyses are incorporated in this study. Therefore, influences of the content of recycled Kevlar® fibers, implementation of thermal treatment, and immersion periods on the tensile strength of recycled Kevlar®/PET/LPET nonwoven geotextiles are examined, after which their influential levels are statistically determined by performing multiple regression analyses. According to the results, the tensile strength of nonwoven geotextiles can be enhanced by adding recycled Kevlar® fibers and thermal treatment.

Biodegradable polyester films from renewable aleuritic acid: surface modifications induced by melt-polycondensation in air

International Nuclear Information System (INIS)

Benítez, José Jesús; De Vargas-Parody, María Inmaculada; Cruz-Carrillo, Miguel Antonio; Heredia-Guerrero, José Alejandro; Morales-Flórez, Victor; De la Rosa-Fox, Nicolás; Heredia, Antonio

2016-01-01

Good water barrier properties and biocompatibility of long-chain biopolyesters like cutin and suberin have inspired the design of synthetic mimetic materials. Most of these biopolymers are made from esterified mid-chain functionalized ω-long chain hydroxyacids. Aleuritic (9,10,16-trihydroxypalmitic) acid is such a polyhydroxylated fatty acid and is also the major constituent of natural lac resin, a relatively abundant and renewable resource. Insoluble and thermostable films have been prepared from aleuritic acid by melt-condensation polymerization in air without catalysts, an easy and attractive procedure for large scale production. Intended to be used as a protective coating, the barrier's performance is expected to be conditioned by physical and chemical modifications induced by oxygen on the air-exposed side. Hence, the chemical composition, texture, mechanical behavior, hydrophobicity, chemical resistance and biodegradation of the film surface have been studied by attenuated total reflection–Fourier transform infrared spectroscopy (ATR–FTIR), atomic force microscopy (AFM), nanoindentation and water contact angle (WCA). It has been demonstrated that the occurrence of side oxidation reactions conditions the surface physical and chemical properties of these polyhydroxyester films. Additionally, the addition of palmitic acid to reduce the presence of hydrophilic free hydroxyl groups was found to have a strong influence on these parameters. (paper)

Effective Interfacially Polymerized Polyester Solvent Resistant Nanofiltration Membrane from Bioderived Materials

KAUST Repository

Abdellah, Mohamed H.; Perez Manriquez, Liliana; Puspasari, Tiara; Scholes, Colin A.; Kentish, Sandra E.; Peinemann, Klaus-Viktor

2018-01-01

Utilization of sustainable and environmentally friendly solvents for the preparation of membranes has attracted growing interest in recent years. In this work, a polyester thin film composite solvent resistant nanofiltration (SRNF) membrane

Measurement of salivary cortisol--effects of replacing polyester with cotton and switching antibody

DEFF Research Database (Denmark)

Hansen, Ase Marie; Garde, Anne Helene; Persson, Roger

2008-01-01

measurements in our laboratory were affected by: 1) changes in the tampon material and 2) changes in the antibody of the analytical kit. In study 1, saliva from healthy subjects (n = 19) was split and spiked to Salivette polyester and cotton tampons, respectively, and treated as ordinary samples before being...... analysed for cortisol using a Spectria RIA kit for cortisol. In study 2, 68 anonymous saliva samples were analysed with the Spectria Cortisol RIA kit both before and after the manufacturer changed the antibody. The change from polyester to cotton tampons reduced the measured concentration of salivary...

Effects of gamma irradiation on the molecular structure and mechanical properties of biodegradable polymer poly(hydroxybutyrate)

International Nuclear Information System (INIS)

Oliveira, Leticia M. de; Araujo, Elmo S.

2005-01-01

The effects of gamma irradiation ( 60 Co) on the properties of the Brazilian biodegradable polymer, Poly(hydroxybutyrate), PHB, i.e. chemical, mechanical and structural properties were investigated. PHB is a natural polyester biosynthesized by different bacteria as a form to store carbon and energy. This new biopolymer shows a great potential in the medical and pharmaceutical applications due to the biocompatibility and biodegradation capacity, since it is reabsorbed by organism without liberation of toxic substances. As it.s well known, gamma irradiation have been considered the more functional sterilization mechanism applied to medical devices. This way, it is necessary to know the effects caused by energy transfer to the polymer system. The viscosity-average molar mass (Mv) of the irradiated PHB, measured using an Ostwald-type capillary viscometer, significantly decreased. The irradiated samples (test specimens) showed a molecular degradation degree, G (scissions/100 eV) value, in the sterilization dose range (0-25 kGy) about 11.4, and 20.9 to doses above 35 kGy. Other results also indicate that the gamma irradiation significantly affected the mechanical properties of PHB. Tensile strength, impact strength and elongation at break decreased dramatically, indicating increasing on the brittleness, because significant chain scissions take place in the amorphous region of irradiated PHB. On the other hand, Young modulus does not significantly change on irradiated polymer. 13 C NMR spectra of irradiated PHB at dose of 200 kGy did not show arising of new structural groups. (author)

Plasma treatment of polyester fabric to impart the water repellency ...

Indian Academy of Sciences (India)

test method 39 (1971). ... pilot production line [7]. It is found that prior .... experiment was set up for testing the absorbancy of modified polyester fabric as in case of .... New Delhi for providing the research grant under TAPTEC scheme. We are ...

Mechanical properties of water hyacinth fibers – polyester composites before and after immersion in water

International Nuclear Information System (INIS)

Abral, H.; Kadriadi, D.; Rodianus, A.; Mastariyanto, P.; Ilhamdi; Arief, S.; Sapuan, S.M.; Ishak, M.R.

2014-01-01

Highlights: • Moisture absorption of water hyacinth (WH) fibers was measured. • WH fibers polyester composites immersed in water decreased mechanical properties. • Improvement fibers fraction in polyester increases mechanical properties. - Abstract: This study reported moisture absorption of untreated and treated individual water hyacinth (WH) fibers as well as comparison the mechanical properties of WH fibers – unsaturated polyester (UPR) matrix composites after and before immersion in water. The result shows that the individual WH fibers treated with various alkali concentration did not exhibit significantly decreases of their moisture absorption. SEM photograph in cross section of the treated WH fibers shows swollen cell wall containing more nano and micro hollows. Tensile and flexure strength of the wet composite samples are lower than that of dried ones. However, increases volume fraction of the WH fibers in UPR matrix affected slightly on enhancement mechanical properties of the composite samples

Sup(1)H n.m.r. relaxation of radiation induced crosslinking in polyester-styrene systems

International Nuclear Information System (INIS)

Andreis, M.; Veksli, Z.; Ranogajec, F.; Hedvig, P.

1989-01-01

The structure and dynamics of a network formed by radiation induced crosslinking of polyesters based on 1,6-hexane diol and 1,2-propylene glycol and maleic anhydride (HDF and PGF, respectively) with styrene is studied by proton pulsed n.m.r. spectroscopy. The dependence of spin-lattice, T 1 , and spin-spin, T 2 , relaxation times on the structure of polyester chain, molar ratios of styrene to polyester unsaturations and the radiation doses are analysed in terms of network formation and structure, and their effect on molecular motion. Above the gel point, at temperatures above the glass transition, the presence of two T 2 components reflects the heterogeneity of the network structure in both resins. Parallel with the n.m.r. relaxation measurements the crosslink density was determined from the extracted gel phase or double bonds (fumaric and styrene) participating in the crosslinking process. (author)

Biodegradable congress 2012; Bioschmierstoff-Kongress 2012

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-11-01

Within the Guelzower expert discussions at 5th and 6th June, 2012 in Oberhausen (Federal Republic of Germany) the following lectures were held: (1) Promotion of biodegradable lubricants by means of research and development as well as public relations (Steffen Daebeler); (2) Biodegradable lubricants - An overview of the advantages and disadvantages of the engaged product groups (Hubertus Murrenhoff); (3) Standardization of biodegradable lubricants - CEN/DIN standard committees - state of the art (Rolf Luther); (4) Market research for the utilization of biodegradable lubricants and means of proof of sustainability (Norbert Schmitz); (5) Fields of application for high performance lubricants and requirements upon the products (Gunther Kraft); (6) Investigations of biodegradable lubricants in rolling bearings and gears (Christoph Hentschke); (7) Biodegradable lubricants in central lubrication systems Development of gears and bearings of offshore wind power installations (Reiner Wagner); (8) Investigations towards environmental compatibility of biodegradable lubricants used in offshore wind power installations (Tolf Schneider); (9) Development of glycerine based lubricants for the industrial metalworking (Harald Draeger); (10) Investigations and utilization of biodegradable oils as electroinsulation oils in transformers (Stefan Tenbohlen); (11) Operational behaviour of lubricant oils in vegetable oil operation and Biodiesel operation (Horst Hamdorf); (12) Lubrication effect of lubricating oil of the third generation (Stefan Heitzig); (13) Actual market development from the view of a producer of biodegradable lubricants (Frank Lewen); (14) Utilization of biodegradable lubricants in forestry harvesters (Guenther Weise); (15) New biodegradable lubricants based on high oleic sunflower oil (Otto Botz); (16) Integrated fluid concept - optimized technology and service package for users of biodegradable lubricants (Juergen Baer); (17) Utilization of a bio oil sensor to control

Study of compounds emitted during thermo-oxidative decomposition of polyester fabrics

Directory of Open Access Journals (Sweden)

Dzięcioł Małgorzata

2016-03-01

Full Text Available Compounds emitted during thermo-oxidative decomposition of three commercial polyester fabrics for indoor outfit and decorations (upholstery, curtains were studied. The experiments were carried out in a flow tubular furnace at 600°C in an air atmosphere. During decomposition process the complex mixtures of volatile and solid compounds were emitted. The main volatile products were carbon oxides, benzene, acetaldehyde, vinyl benzoate and acetophe-none. The emitted solid compounds consisted mainly of aromatic carboxylic acids and its derivatives, among which the greatest part took terephthalic acid, monovinyl terephthalate and benzoic acid. The small amounts of polycyclic aromatic hydrocarbons were also emitted. The emission profiles of the tested polyester fabrics were similar. The presence of toxic compounds indicates the possibility of serious hazard for people during fire.

Development of sugar palm yarn/glass fibre reinforced unsaturated polyester hybrid composites

Science.gov (United States)

Nurazzi, N. Mohd; Khalina, A.; Sapuan, S. Mohd; Rahmah, M.

2018-04-01

This study investigates the effect of fibre hybridization for sugar palm yarn fibre with glass fibre reinforced with unsaturated polyester composites. In this work, unsaturated polyester resin are reinforced with fibre at a ratio of 70:30 wt% and 60:40 wt%. The hybrid composites were characterized in terms of physical (density and water absorption), mechanical (tensile, flexural and compression) and thermal properties through thermal gravimetry analysis (TGA). Density determination showed that density increased with higher wt% of glass fibre. The inherently higher density of glass fibre increased the density of hybrid composite. Resistance to water absorption is improved upon the incorporation of glass fibre and the hybrid composites were found to reach equilibrium absorption at days 4 and 5. As for mechanical performance, the highest tensile strength, tensile modulus, flexural strength, flexural modulus and compression strength were obtained from 40 wt% of fibres reinforcement with ratio of 50:50 wt% of sugar palm yarn fibre and glass fibre reinforced unsaturated polyester composites. The increase of glass fibre loading had a synergistic effect on the mechanical properties to the composites structure due to its superior strength and modulus. The thermal stability of hybrid composites was improved by the increase of onset temperature and the reduction of residues upon increase in temperature.

Thermal Aging of Unsaturated Polyester Composite Reinforced with E-Glass Nonwoven Mat

Directory of Open Access Journals (Sweden)

Hossain Milon

2017-12-01

Full Text Available An experiment was carried out using glass fiber (GF as reinforcing materials with unsaturated polyester matrix to fabricate composite by hand layup technique. Four layers of GF were impregnated by polyester resin and pressed under a load of 5 kg for 20 hours. The prepared composite samples were treated by prolonged exposure to heat for 1 hour at 60-150°C and compared with untreated GF-polyester composite. Different mechanical test of the fabricated composite were investigated. The experiment depicted significant improvement in the mechanical properties of the fabricated composite resulted from the heat treatment. The maximum tensile strength of 200.6 MPa is found for 90°C heat-treated sample. The mechanical properties of the composite do seem to be very affected negatively above 100°C. Water uptake of the composite was carried out and thermal stability of the composite was investigated by thermogravimetric analysis, and it was found that the composite is stable up to 600°C. Fourier transform infrared spectroscopy shows the characteristic bond in the composite. Finally, the excellent elevated heat resistant capacity of glass-fiber-reinforced polymeric composite shows the suitability of its application to heat exposure areas such as kitchen furniture materials, marine, and electric board.

A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Tang, Xiaoning [College of Textiles, Qingdao University, Qingdao, Shandong 266071 (China); Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Tian, Mingwei [College of Textiles, Qingdao University, Qingdao, Shandong 266071 (China); Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, Qingdao University, Qingdao, Shandong 266071 (China); Qu, Lijun, E-mail: lijunqu@126.com [College of Textiles, Qingdao University, Qingdao, Shandong 266071 (China); Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, Qingdao University, Qingdao, Shandong 266071 (China); Zhu, Shifeng [College of Textiles, Qingdao University, Qingdao, Shandong 266071 (China); Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Guo, Xiaoqing [College of Textiles, Qingdao University, Qingdao, Shandong 266071 (China); Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, Qingdao University, Qingdao, Shandong 266071 (China); Han, Guangting [Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao, Shandong 266071 (China); Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, Qingdao University, Qingdao, Shandong 266071 (China); and others

2014-10-30

Highlights: • Multifunctional knit polyester fabric was facile fabricated by the combination of pad-dry-cure process and in situ chemical polymerization route. • High electrical conductivity and efficient water-repellent properties were endowed to the polymer nanocomposite coated fabric. • The polymer nanocomposite coated fabric also performed efficient and durable photocatalytic activities under the illumination of ultraviolet light. - Abstract: Knit polyester fabric was successively modified and decorated with chitosan layer and polyaniline polymer nanocomposite layer in this paper. The fabric was firstly treated with chitosan to form a stable layer through the pad-dry-cure process, and then the polyaniline polymer nanocomposite layer was established on the outer layer by in situ chemical polymerization method using ammonium persulfate as oxidant and chlorhydric acid as dopant. The surface morphology of coated fabric was characterized by scanning electron microscopy (SEM), and the co-existence of chitosan layer and granular polyaniline polymer nanocomposite was confirmed and well dispersed on the fabric surface. The resultant fabric was endowed with remarkable electrical conductivity properties and efficient water-repellent capability, which also have been found stable after water laundering. In addition, the photocatalytic decomposition activity for reactive red dye was observed when the multifunctional knit polyester fabric was exposed to the illumination of ultraviolet lamp. These results indicated that chitosan and polyaniline polymer nanocomposite could form ideal multifunctional coatings on the surface of knit polyester fabric.

A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite

International Nuclear Information System (INIS)

Tang, Xiaoning; Tian, Mingwei; Qu, Lijun; Zhu, Shifeng; Guo, Xiaoqing; Han, Guangting

2014-01-01

Highlights: • Multifunctional knit polyester fabric was facile fabricated by the combination of pad-dry-cure process and in situ chemical polymerization route. • High electrical conductivity and efficient water-repellent properties were endowed to the polymer nanocomposite coated fabric. • The polymer nanocomposite coated fabric also performed efficient and durable photocatalytic activities under the illumination of ultraviolet light. - Abstract: Knit polyester fabric was successively modified and decorated with chitosan layer and polyaniline polymer nanocomposite layer in this paper. The fabric was firstly treated with chitosan to form a stable layer through the pad-dry-cure process, and then the polyaniline polymer nanocomposite layer was established on the outer layer by in situ chemical polymerization method using ammonium persulfate as oxidant and chlorhydric acid as dopant. The surface morphology of coated fabric was characterized by scanning electron microscopy (SEM), and the co-existence of chitosan layer and granular polyaniline polymer nanocomposite was confirmed and well dispersed on the fabric surface. The resultant fabric was endowed with remarkable electrical conductivity properties and efficient water-repellent capability, which also have been found stable after water laundering. In addition, the photocatalytic decomposition activity for reactive red dye was observed when the multifunctional knit polyester fabric was exposed to the illumination of ultraviolet lamp. These results indicated that chitosan and polyaniline polymer nanocomposite could form ideal multifunctional coatings on the surface of knit polyester fabric

ANAEROBIC BIODEGRADATION OF A BIODEGRADABLE MATERIAL UNDER ANAEROBIC - THERMOPHILIC DIGESTION

Directory of Open Access Journals (Sweden)

RICARDO CAMACHO-MUÑOZ

2014-12-01

Full Text Available This paper dertermined the anaerobic biodegradation of a polymer obtained by extrusion process of native cassava starch, polylactic acid and polycaprolactone. Initially a thermophilic - methanogenic inoculum was prepared from urban solid waste. The gas final methane concentration and medium’s pH reached values of 59,6% and 7,89 respectively. The assay assembly was carried out according ASTM D5511 standard. The biodegradation percent of used materials after 15 day of digestion were: 77,49%, 61,27%, 0,31% for cellulose, sample and polyethylene respectively. Due cellulose showed biodegradation levels higher than 70% it’s deduced that the inoculum conditions were appropriate. A biodegradation level of 61,27%, 59,35% of methane concentration in sample’s evolved gas and a medium’s finale pH of 7,71 in sample’s vessels, reveal the extruded polymer´s capacity to be anaerobically degraded under thermophilic- high solid concentration conditions.

External validation of structure-biodegradation relationship (SBR) models for predicting the biodegradability of xenobiotics.

Science.gov (United States)

Devillers, J; Pandard, P; Richard, B

2013-01-01

Biodegradation is an important mechanism for eliminating xenobiotics by biotransforming them into simple organic and inorganic products. Faced with the ever growing number of chemicals available on the market, structure-biodegradation relationship (SBR) and quantitative structure-biodegradation relationship (QSBR) models are increasingly used as surrogates of the biodegradation tests. Such models have great potential for a quick and cheap estimation of the biodegradation potential of chemicals. The Estimation Programs Interface (EPI) Suite™ includes different models for predicting the potential aerobic biodegradability of organic substances. They are based on different endpoints, methodologies and/or statistical approaches. Among them, Biowin 5 and 6 appeared the most robust, being derived from the largest biodegradation database with results obtained only from the Ministry of International Trade and Industry (MITI) test. The aim of this study was to assess the predictive performances of these two models from a set of 356 chemicals extracted from notification dossiers including compatible biodegradation data. Another set of molecules with no more than four carbon atoms and substituted by various heteroatoms and/or functional groups was also embodied in the validation exercise. Comparisons were made with the predictions obtained with START (Structural Alerts for Reactivity in Toxtree). Biowin 5 and Biowin 6 gave satisfactorily prediction results except for the prediction of readily degradable chemicals. A consensus model built with Biowin 1 allowed the diminution of this tendency.

Cationization and gamma irradiation effects on the dyeability of polyester fabric towards disperse dyes

Energy Technology Data Exchange (ETDEWEB)

Zohdy, Maged H. [Department of Radiation Chemistry, National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt)]. E-mail: mhzohdy@yahoo.com

2005-06-01

The effect of hydrazine hydrate (HZH) treatment and/or gamma irradiation on the dyeing, mechanical and thermal properties of polyester fabrics (PET) was studied. The different factors that may affect the dyeing performance, such as concentrations of HZH, benzyl alcohol and pH values, were investigated. In this regard, the colour strength of untreated polyester fabrics dyed with the dyestuffs Dispersol blue BR, Dispersol orange B2R and Dispersol red B2B was found to be 10.34, 10.76 and 10.12 compared to 24.61, 24.90 and 23.00 in the case of irradiated and HZH-treated polyester fabrics, respectively. These colour strength values were achieved by preirradiation at a dose of 75kGy followed by treatment with 15mll-1 of HZH. Thermogravimetric analysis (TGA) showed that the thermal decomposition stability was improved by using gamma irradiation and the treatment with HZH as indicated by the calculated activation energies. FT-IR spectroscopy showed that the treatment with HZH acts as cationizer prior to dyeing with disperse dyes.

Cationization and gamma irradiation effects on the dyeability of polyester fabric towards disperse dyes

International Nuclear Information System (INIS)

Zohdy, Maged H.

2005-01-01

The effect of hydrazine hydrate (HZH) treatment and/or gamma irradiation on the dyeing, mechanical and thermal properties of polyester fabrics (PET) was studied. The different factors that may affect the dyeing performance, such as concentrations of HZH, benzyl alcohol and pH values, were investigated. In this regard, the colour strength of untreated polyester fabrics dyed with the dyestuffs Dispersol blue BR, Dispersol orange B2R and Dispersol red B2B was found to be 10.34, 10.76 and 10.12 compared to 24.61, 24.90 and 23.00 in the case of irradiated and HZH-treated polyester fabrics, respectively. These colour strength values were achieved by preirradiation at a dose of 75kGy followed by treatment with 15mll-1 of HZH. Thermogravimetric analysis (TGA) showed that the thermal decomposition stability was improved by using gamma irradiation and the treatment with HZH as indicated by the calculated activation energies. FT-IR spectroscopy showed that the treatment with HZH acts as cationizer prior to dyeing with disperse dyes

Preparation and properties of aromatic polyester/TiO{sub 2} nanocomposites from polyethylene terephthalate

Energy Technology Data Exchange (ETDEWEB)

Santos, Leonardo Moreira dos; Carone, Carlos Leonardo Pandolfo; Einloft, Sandra Mara Oliveira; Ligabue, Rosane Angelica, E-mail: rligabue@pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUCRS), Porto Alegre, RS (Brazil). Programa de Graduacao em Engenharia e Tecnologia de Materiais

2016-01-15

The development of polyester based materials with enhanced properties as well as the use of post- consumer plastics as raw material has been an increasing market demand. This work aims the synthesis and characterization of aromatic polyesters/titanium dioxide nanocomposites from PET and using TiO{sub 2} (0, 1, 3 and 5% w/w) as filler by in situ polymerization. The results obtained by DSC, XRD and FTIR analyzes evidenced an interaction between the OH groups on the TiO{sub 2} surface with the ester groups of the polymer leading to decrease of the polymer crystallinity and of hydrophilicity. By SEM images was possible to note a homogeneous distribution of the filler into polymer matrix with 1%w/w TiO{sub 2} (average particle size of 199 nm), however for larger amounts of filler (3 and 5% TiO{sub 2}) revealed the aggregates formation. The results showed an improvement of thermal properties and hardness of the nanocomposites containing TiO{sub 2} nanoparticles compared to pristine polyester. (author)

Construction of 2D transparent micromodels in polyester resin with porosity similar to carrots

Directory of Open Access Journals (Sweden)

Rodrigo Emilio Díaz

2011-12-01

Full Text Available Microscopic visualization, especially in transparent micromodels, can provide valuable information to understand the transport phenomena at pore scale in different process occurring in porous materials (food, timber, soils, etc.. Micromodels studies focus mainly on the observation of multi-phase flow, which presents a greater proximity to reality. The aim of this study was to study the process of flexography and its application in the manufacture of polyester resin transparent micromodels and its application to carrots. Materials used to implement a flexo station for micromodels construction were thermoregulated water bath, exposure chamber to UV light, photosensitive substance (photopolymer, RTV silicone polyester resin, and glass plates. In this paper, data on size distribution of a particular kind of carrot we used, and a transparent micromodel with square cross-section as well as a Log-normal pore size distribution with pore radii ranging from 10 to 110 µm (average of 22 µm and micromodel size of 10 × 10 cm were built. Finally, it stresses that it has successfully implemented the protocol processing 2D polyester resin transparent micromodels.

Chemical structures and thermal properties of polyesters obtained from different samples of bio diesel epoxidized

International Nuclear Information System (INIS)

Samios, Dimitrios; Reiznautt, Quelen B.; Nicolau, Aline; Martini, Denise D.; Chagas, Arthur L. das

2009-01-01

In this work new structures from oligo esters and polyesters from different oils (olive oil, sunflower oil and linseed oil) were synthesized and characterized. Oligo esters and polyesters were synthesized from the reaction of fatty acid methyl epoxy-esters, obtained from different oils, with cis-1,2-cyclohexanedicarboxylic anhydride in the presence of triethylamine (TEA). Different amounts of the resin 1,4-butanediol diglycidyl ether (BDGE) were added in order to increase the capacity of crosslinking. The molar ratio of BDGE used in system was between 0 and 0.066. The intermediate structures, as well as the oligo esters and polyesters produced, were analyzed by using Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance ( 1 H - NMR). The thermal behavior of the products was realized through differential scanning calorimetry and Thermogravimetric analyses. The presence of BDGE in the materials chains increases the bonding capacity resulting in a higher molecular weight material which presents good thermal stability. (author)

Comparison of Cashew Nut Shell Liquid (CNS) Resin with Polyester ...

African Journals Online (AJOL)

Akorede

cobalt amine (accelerator), methyl ethyl ketone peroxide (catalyst) to develop two sets of ... shell liquid (CNSL) resin were comparable to those developed with polyester resin. ... permit diffusion of water, this function is often not adequately ... When designed ... blades in gas turbine engines, wing leading edges and flaps.

Characterization of material composite marble-polyester

Directory of Open Access Journals (Sweden)

Corpas, F. A.

2002-12-01

Full Text Available In this work we characterize a new material composite, formed with a polyester and crushed white marble mixture. The final purpose is double: to obtain a material for applications sufficiently competitive after an economic viability study, increasing the yield of the main commodity, using waste marble and improving the jobs in the quarries area. From the results obtained, we deduce then that this material could be used to inside and outside adornment.

En este trabajo, caracterizamos un nuevo material compuesto, formado con una mezcla de poliéster y de mármol blanco triturado. El propósito final es doble: por un lado obtener un material para aplicaciones lo suficientemente competitivas como para que se pueda iniciar un estudio económico de viabilidad, aumentando el rendimiento de la materia prima y mejorando las salidas laborales de las comarcas extractoras. Para la caracterización del material se ha determinado el porcentaje adecuado de poliéster. Así como las propiedades mecánicas (flexión, compresión y dureza, químicas, fatiga térmica y su influencia a la exposición solar In order to characterized of material, we have determined the suitable porcentage of polyester Also we have carried out a study of the mechanical (stretching, resistance to traction, hardeness and thermal fatigue chemicals properties and solar radiation influence. De los resultados obtenidos, este material podría ser utilizado para ornamentación tanto de interior como de exterior.

Biodegradation of selected offshore chemicals

OpenAIRE

Wennberg, Aina C.; Petersen, Karina

2017-01-01

A review of biodegradation data for specific oil field chemicals and chemical groups were performed in order to evaluate if the current categorisation of these were appropriate based on the biodegradation properties. Data were compiled from databases like ECHA and MITI and from the literature. For compounds with limited or inconclusive test data, biodegradation was also estimated by the BIOWIN models, and the EAWAG-BBD pathway prediction system was used to predict plausible biodegradation pat...

Characterization of polyester composites from recycled polyethylene terephthalate reinforced with empty fruit bunch fibers

International Nuclear Information System (INIS)

Tan, Chiachun; Ahmad, Ishak; Heng, Muichin

2011-01-01

Highlights: → Unsaturated polyester resin (UPR) was synthesized from recycled PET. → Effect of surface treatment on EFB/UPR was studied. → Treatment on EFB improved the mechanical and thermal properties. → Treatment on EFB also improved fiber-matrix interaction. -- Abstract: Unsaturated polyester resin (UPR) was synthesized from recycled polyethylene terephthalate (PET) which acted as a matrix for the preparation of UPR/empty fruit bunch fibers (EFB) composite. Chemical recycling on fine pieces of PET bottles were conducted through glycolysis process using ethylene glycol. The unsaturated polyester resin (UPR) was then prepared by reacting the glycolysed product with maleic anhydride. FTIR analysis of glycolyzed product and prepared UPR showed that cross-links between unsaturated polyester chain and styrene monomer occurred at the unsaturated sites which resulted in the forming of cross-linking network. The preparation of UPR/EFB composite was carried out by adding EFB into prepared UPR matrix. The effects of surface treatment on EFB with sodium hydroxide solution (NaOH), silane coupling agent and maleic anhydride (MA) were then studied. The experimental results showed that treated EFB have higher values of tensile and impact strength compared with untreated EFB. The best results were obtained for silane treatment followed by MA and NaOH treatments where the tensile strength was increased by about 21%, 18% and 13% respectively. SEM micrographs of the tensile fracture surfaces of UPR/EFB composite also proved that treatment on EFB has increased the interfacial adhesion between the fiber and UPR matrix compared to the untreated UPR/EFB composite.

Comparative study on the biodegradation and biocompatibility of silicate bioceramic coatings on biodegradable magnesium alloy as biodegradable biomaterial

Science.gov (United States)

Razavi, M.; Fathi, M. H.; Savabi, O.; Razavi, S. M.; Hashemibeni, B.; Yazdimamaghani, M.; Vashaee, D.; Tayebi, L.

2014-03-01

Many clinical cases as well as in vivo and in vitro assessments have demonstrated that magnesium alloys possess good biocompatibility. Unfortunately, magnesium and its alloys degrade too quickly in physiological media. In order to improve the biodegradation resistance and biocompatibility of a biodegradable magnesium alloy, we have prepared three types of coating include diopside (CaMgSi2O6), akermanite (Ca2MgSi2O6) and bredigite (Ca7MgSi4O16) coating on AZ91 magnesium alloy through a micro-arc oxidation (MAO) and electrophoretic deposition (EPD) method. In this research, the biodegradation and biocompatibility behavior of samples were evaluated in vitro and in vivo. The in vitro analysis was performed by cytocompatibility and MTT-assay and the in vivo test was conducted on the implantation of samples in the greater trochanter of adult rabbits. The results showed that diopside coating has the best bone regeneration and bredigite has the best biodegradation resistance compared to others.

Use Of Biodegradation Ratios In Monitoring Trend Of Biostimulated Biodegradation In Crude Oil Polluted Soils

Directory of Open Access Journals (Sweden)

Okorondu

2017-03-01

Full Text Available This study deals with biodegradation experiment on soil contaminated with crude oil. The soil sample sets A BC D E F G were amended with inorganic fertilizer to enhance microbial growth and hydrocarbon degradation moisture content of some of the sets were as well varied. Biodegradation ratios nC17Pr nC18Ph and nC17nC18PrPh were used to monitor biodegradation of soil sets A BC D E F G for a period of 180. The soil samples were each contaminated with the same amount of crude oil and exposed to specific substrate treatment regarding the amount of nutrients and water content over the same period of time. The trend in biodegradation of the different soil sample sets shows that biodegradation ratio nC17nC18PrPh was more reflective of and explains the biodegradation trend in all the sample sets throughout the period of the experiment hence a better parameter ratio for monitoring trend of biostimulated biodegradation. The order of preference of the biodegradation ratios is expressed as nC18Ph nC17Pr nC17nC18 PrPh. This can be a relevant support tool when designing bioremediation plan on field.

Microbial production of polyhydroxyalkanoates (PHAs) and its copolymers: A review of recent advancements.

Science.gov (United States)

Anjum, Anbreen; Zuber, Mohammad; Zia, Khalid Mahmood; Noreen, Aqdas; Anjum, Muhammad Naveed; Tabasum, Shazia

2016-08-01

Traditional mineral oil based plastics are important commodity to enhance the comfort and quality of life but the accumulation of these plastics in the environment has become a major universal problem due to their low biodegradation. Solution to the plastic waste management includes incineration, recycling and landfill disposal methods. These processes are very time consuming and expensive. Biopolymers are important alternatives to the petroleum-based plastics due to environment friendly manufacturing processes, biodegradability and biocompatibility. Therefore use of novel biopolymers, such as polylactide, polysaccharides, aliphatic polyesters and polyhydroxyalkanoates is of interest. PHAs are biodegradable polyesters of hydroxyalkanoates (HA) produced from renewable resources by using microorganisms as intracellular carbon and energy storage compounds. Even though PHAs are promising candidate for biodegradable polymers, however, the production cost limit their application on an industrial scale. This article provides an overview of various substrates, microorganisms for the economical production of PHAs and its copolymers. Recent advances in PHAs to reduce the cost and to improve the performance of PHAs have also been discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Phthalates biodegradation in the environment.

Science.gov (United States)

Liang, Da-Wei; Zhang, Tong; Fang, Herbert H P; He, Jianzhong

2008-08-01

Phthalates are synthesized in massive amounts to produce various plastics and have become widespread in environments following their release as a result of extensive usage and production. This has been of an environmental concern because phthalates are hepatotoxic, teratogenic, and carcinogenic by nature. Numerous studies indicated that phthalates can be degraded by bacteria and fungi under aerobic, anoxic, and anaerobic conditions. This paper gives a review on the biodegradation of phthalates and includes the following aspects: (1) the relationship between the chemical structure of phthalates and their biodegradability, (2) the biodegradation of phthalates by pure/mixed cultures, (3) the biodegradation of phthalates under various environments, and (4) the biodegradation pathways of phthalates.

The identification of cutin synthase: formation of the plant polyester cutin

DEFF Research Database (Denmark)

Yeats, Trevor H.; Martin, Laetitia B. B.; Viart, Helene Marie-France

2012-01-01

A hydrophobic cuticle consisting of waxes and the polyester cutin covers the aerial epidermis of all land plants, providing essential protection from desiccation and other stresses. We have determined the enzymatic basis of cutin polymerization through characterization of a tomato extracellular...

Reduced toxicity polyester resins and microvascular pre-preg tapes for advanced composites manufacturing

Science.gov (United States)

Poillucci, Richard

Advanced composites manufacturing broadly encapsulates topics ranging from matrix chemistries to automated machines that lay-up fiber-reinforced materials. Environmental regulations are stimulating research to reduce matrix resin formulation toxicity. At present, composites fabricated with polyester resins expose workers to the risk of contact with and inhalation of styrene monomer, which is a potential carcinogen, neurotoxin, and respiratory irritant. The first primary goal of this thesis is to reduce the toxicity associated with polyester resins by: (1) identification of potential monomers to replace styrene, (2) determination of monomer solubility within the polyester, and (3) investigation of approaches to rapidly screen a large resin composition parameter space. Monomers are identified based on their ability to react with polyester and their toxicity as determined by the Globally Harmonized System (GHS) and a green screen method. Solubilities were determined by the Hoftyzer -- Van Krevelen method, Hansen solubility parameter database, and experimental mixing of monomers. A combinatorial microfluidic mixing device is designed and tested to obtain distinct resin compositions from two input chemistries. The push for safer materials is complemented by a thrust for multifunctional composites. The second primary goal of this thesis is to design and implement the manufacture of sacrificial fiber materials suitable for use in automated fiber placement of microvascaular multifunctional composites. Two key advancements are required to achieve this goal: (1) development of a roll-to-roll method to place sacrificial fibers onto carbon fiber pre-preg tape; and (2) demonstration of feasible manufacture of microvascular carbon fiber plates with automated fiber placement. An automated method for placing sacrificial fibers onto carbon fiber tapes is designed and a prototype implemented. Carbon fiber tows with manual placement of sacrificial fibers is implemented within an

High Throughput Screening of Valganciclovir in Acidic Microenvironments of Polyester Thin Films

Directory of Open Access Journals (Sweden)

Teilo Schaller

2015-04-01

Full Text Available Ganciclovir and valganciclor are antiviral agents used for the treatment of cytomegalovirus retinitis. The conventional method for administering ganciclovir in cytomegalovirus retinitis patients is repeated intravitreal injections. In order to obviate the possible detrimental effects of repeated intraocular injections, to improve compliance and to eliminate systemic side-effects, we investigated the tuning of the ganciclovir pro-drug valganciclovir and the release from thin films of poly(lactic-co-glycolic acid (PLGA, polycaprolactone (PCL, or mixtures of both, as a step towards prototyping periocular valganciclovir implants. To investigate the drug release, we established and evaluated a high throughput fluorescence-based quantification screening assay for the detection of valganciclovir. Our protocol allows quantifying as little as 20 ng of valganciclovir in 96-well polypropylene plates and a 50× faster analysis compared to traditional HPLC measurements. This improvement can hence be extrapolated to other polyester matrix thin film formulations using a high-throughput approach. The acidic microenvironment within the polyester matrix was found to protect valganciclovir from degradation with resultant increases in the half-life of the drug in the periocular implant to 100 days. Linear release profiles were obtained using the pure polyester polymers for 10 days and 60 days formulations; however, gross phase separations of PCL and acid-terminated PLGA prevented tuning within these timeframes due to the phase separation of the polymer, valganciclovir, or both.

Design of Functional Polyesters for Electronic and Biological Applications

OpenAIRE

Nelson, Ashley Marie

2015-01-01

Melt polymerization and novel monomers enabled the synthesis of polyesters for electronic and biological applications. Inspiration from nature and a passion for environmental preservation instigated an emphasis on the incorporation of renewable resources into polymeric materials. Critical analysis of current research surrounding bisphenol-A replacements and ioncontaining segmented polyurethanes aided in identifying benchmark polymers, including limitations, challenges, and future needs. Struc...

Tandem mass spectrometry characteristics of polyester anions and cations formed by electrospray ionization.

Science.gov (United States)

Arnould, Mark A; Buehner, Rita W; Wesdemiotis, Chrys; Vargas, Rafael

2005-01-01

Electrospray ionization of polyesters composed of isophthalic acid and neopentyl glycol produces carboxylate anions in negative mode and mainly sodium ion adducts in positive mode. A tandem mass spectrometry (MS/MS) study of these ions in a quadrupole ion trap shows that the collisionally activated dissociation pathways of the anions are simpler than those of the corresponding cations. Charge-remote fragmentations predominate in both cases, but the spectra obtained in negative mode are devoid of the complicating cation exchange observed in positive mode. MS/MS of the Na(+) adducts gives rise to a greater number of fragments but not necessarily more structural information. In either positive or negative mode, polyester oligomers with different end groups fragment by similar mechanisms. The observed fragments are consistent with rearrangements initiated by the end groups. Single-stage ESI mass spectra also are more complex in positive mode because of extensive H/Na substitutions; this is also true for matrix-assisted laser desorption ionization (MALDI) mass spectra. Hence, formation and analysis of anions might be the method of choice for determining block length, end group structure and copolymer sequence, provided the polyester contains at least one carboxylic acid end group that is ionizable to anions.

Polyurethane coating from prepolymers and Crambe oil polyesters in oxygenates and green solvents

International Nuclear Information System (INIS)

Pinto, Elaine R.P.; Messaddeq, Younes; Polito, Wagner Luiz; Matinelli, Marcia

2015-01-01

The PU coatings are extremely used in areas that require high-performance. For several applications PU resin, the solvent base is commonly used, the problem is the solvents with high content of volatile organic compounds (VCO) like: toluene, xylene, benzene, etc.. In this work, we were synthesized and characterized four kinds of prepolymers with low-VCO from renewable sources such as castor oil and crambe oil with oxygenate and green solvents. The PU prepolymers had been synthesized in the proportions NCO/OH 2:1 and 3:1. The curing process was carried out with atmospheric moisture in the films. Characterization was made from prepolymers, oligomers and polyesters and PU films by FTIR, TGA / DTA, NMR, GPC and GC-FID, besides this the coatings were applied on aluminum and glass plates and, subjected to analysis chamber saline, hardness and adhesion. The results indicated that the reaction occurred between the prepolymers with oligomers or polyesters, because disappearance of the NCO band at 2270 cm"-"1. The PU films showed good thermal stability (> 270 °C), high tensile strength and deformation. Surround the formulations, the PU films with HDI prepolymers showed the best results with polyesters from crambe oil (PEC 02 and PEC 03). (author)

Material characterization of a polyester resin system for the pultrusion process

DEFF Research Database (Denmark)

Baran, Ismet; Akkerman, Remko; Hattel, Jesper Henri

2014-01-01

In the present work, the chemo-rheology of an industrial ‘‘orthophthalic’’ polyester system specifically prepared for a pultrusion process is characterized. The curing behaviour is first characterized using the differential scanning calorimetry (DSC). Isothermal and dynamic scans are performed...

Effect of particle size and concentration on the mechanical properties of polyester/date palm seed particulate composites

Directory of Open Access Journals (Sweden)

Alewo Opuada AMEH

2015-05-01

Full Text Available The use of cellulosic materials as reinforcement in composites can greatly enhance their properties. The thrust of this study was to investigate the effect of date palm seed particle on the properties of reinforced polyester. Unsaturated polyester resin was reinforced with date palm seed particles of 0.5, 2.0 and 2.8mm particle sizes using variable particle loadings of 5, 10, 15, 20 and 25wt%. The composites obtained were subjected to various types of mechanical and physical tests in order to assess their performance. The optimum tensile strength of 16.7619N/mm2 and elastic modulus of 343.8N/mm2 were attained at 15wt% and 10wt% loading (using 0.5mm particles respectively and percent water absorption was found to be least for 0.5mm particle size. The hardness was enhanced to the maximum of 74 HRF (Rockwell Hardness Factor by 2mm particle size at 25wt% loading. Pure unsaturated polyester resin recorded tensile strength of 17.5959N/mm2, elastic modulus of 316.7N/mm2 and hardness of 33.5 HRF. The results indicated that the use of date palm seed particles as reinforcement can enhance the properties of polyester composites.

External validation of EPIWIN biodegradation models.

Science.gov (United States)

Posthumus, R; Traas, T P; Peijnenburg, W J G M; Hulzebos, E M

2005-01-01

The BIOWIN biodegradation models were evaluated for their suitability for regulatory purposes. BIOWIN includes the linear and non-linear BIODEG and MITI models for estimating the probability of rapid aerobic biodegradation and an expert survey model for primary and ultimate biodegradation estimation. Experimental biodegradation data for 110 newly notified substances were compared with the estimations of the different models. The models were applied separately and in combinations to determine which model(s) showed the best performance. The results of this study were compared with the results of other validation studies and other biodegradation models. The BIOWIN models predict not-readily biodegradable substances with high accuracy in contrast to ready biodegradability. In view of the high environmental concern of persistent chemicals and in view of the large number of not-readily biodegradable chemicals compared to the readily ones, a model is preferred that gives a minimum of false positives without a corresponding high percentage false negatives. A combination of the BIOWIN models (BIOWIN2 or BIOWIN6) showed the highest predictive value for not-readily biodegradability. However, the highest score for overall predictivity with lowest percentage false predictions was achieved by applying BIOWIN3 (pass level 2.75) and BIOWIN6.

Mechanical characterization of glass fiber (woven roving/chopped strand mat E-glass fiber) reinforced polyester composites

Science.gov (United States)

Bhaskar, V. Vijaya; Srinivas, Kolla

2017-07-01

Polymer reinforced composites have been replacing most of the engineering material and their applications become more and more day by day. Polymer composites have been analyzing from past thirty five years for their betterment for adapting more applications. This paper aims at the mechanical properties of polyester reinforced with glass fiber composites. The glass fiber is reinforced with polyester in two forms viz Woven Rovings (WRG) and Chopped Strand Mat (CSMG) E-glass fibers. The composites are fabricated by hand lay-up technique and the composites are cut as per ASTM Standard sizes for corresponding tests like flexural, compression and impact tests, so that flexural strength, compression strength, impact strength and inter laminar shear stress(ILSS) of polymer matrix composites are analyzed. From the tests and further calculations, the polyester composites reinforced with Chopped Strand Mat glass fiber have shown better performance against flexural load, compression load and impact load than that of Woven Roving glass fiber.

Biodegradation of lubricant oil

African Journals Online (AJOL)

M

2012-09-25

Sep 25, 2012 ... lubricating oil, showed high biodegradation efficiency for different used lubricating oils. Capability of ..... amount after biodegradation showed no difference in the .... products polluted sites in Elele, Rivers State, Ngeria.

A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite

Science.gov (United States)

Tang, Xiaoning; Tian, Mingwei; Qu, Lijun; Zhu, Shifeng; Guo, Xiaoqing; Han, Guangting; Sun, Kaikai; Hu, Xili; Wang, Yujiao; Xu, Xiaoqi

2014-10-01

Knit polyester fabric was successively modified and decorated with chitosan layer and polyaniline polymer nanocomposite layer in this paper. The fabric was firstly treated with chitosan to form a stable layer through the pad-dry-cure process, and then the polyaniline polymer nanocomposite layer was established on the outer layer by in situ chemical polymerization method using ammonium persulfate as oxidant and chlorhydric acid as dopant. The surface morphology of coated fabric was characterized by scanning electron microscopy (SEM), and the co-existence of chitosan layer and granular polyaniline polymer nanocomposite was confirmed and well dispersed on the fabric surface. The resultant fabric was endowed with remarkable electrical conductivity properties and efficient water-repellent capability, which also have been found stable after water laundering. In addition, the photocatalytic decomposition activity for reactive red dye was observed when the multifunctional knit polyester fabric was exposed to the illumination of ultraviolet lamp. These results indicated that chitosan and polyaniline polymer nanocomposite could form ideal multifunctional coatings on the surface of knit polyester fabric.

High Efficiency Particulate Air (HEPA) filters from polyester and polypropylene fibre nonwovens

CSIR Research Space (South Africa)

Boguslavsky, L

2010-10-01

Full Text Available filtration efficiency. Glass fibres are more harmful to human, compared to polypropylene and polyester fibre which are chemically inert. Hydroentanglement and chemical bonding techniques were utilised in manufacturing nonwovens for dry filtration. Acrylic...

Novel biphotonic holographic storage in a side-chain liquid crystalline polyester

DEFF Research Database (Denmark)

Ramanujam, P.S.; Hvilsted, S.; Andruzzi, F.

1993-01-01

We report novel biphotonic holographic storage of text and gratings on unoriented films of a side-chain liquid crystalline polyester capable of high density storage and complete erasure. The holograms have a typical size of 1 mm. The recording utilizes unusual photochemistry involving azo dye...

Aza‐Michael addition reaction: Post‐polymerization modification and preparation of PEI/PEG‐based polyester hydrogels from enzymatically synthesized reactive polymers

DEFF Research Database (Denmark)

Hoffmann, Christian; Stuparu, Mihaiela C.; Daugaard, Anders Egede

2015-01-01

The utility of aza‐Michael addition chemistry for post‐polymerization functionalization of enzymatically prepared polyesters is established. For this, itaconate ester and oligoethylene glycol are selected as monomers. A Candida Antarctica lipase B catalyzed polycondensation reaction between the two...... monomers provides the polyesters, which carry an activated carbon‐carbon double bond in the polymer backbone. These electron deficient alkenes represent suitable aza‐Michael acceptors and can be engaged in a nucleophilic addition reaction with small molecular mono‐amines (aza‐Michael donors) to yield...... functionalized linear polyesters. Employing a poly‐amine as the aza‐Michael donor, on the other hand, results in the formation of hydrophilic polymer networks....

Mechanical Properties Analysis Of Composite Magnetic Base On hexa ferrite And Polyester Or Epoxy Matrix With Silane Additive Addition

International Nuclear Information System (INIS)

Sudirman; Ridwan; Mujamilah; K K, Aloma; Rembulan, Marisa; Fitriyanti

2003-01-01

Application of composite magnetic especially hexa ferrite magnet for industry and home industry in Indonesia has been used. Research purposes were making composite magnetic by mixing hexa ferrite powder with polyester or epoxy and studying the effect of coupling agent 3-aminopropyltriethoxysilane (3-APE) addition on mechanical properties of composite magnetic. The coupling agent may increase bonding properties between magnetic powder and matrix polymer, so that tensile strength of magnetic composite will increase without decreasing the magnetic properties. Magnetic powder (SrM or BaM) wich be coated by coupling agent were added to matrix polyester and mekpo or epoxy and versamid, mixed until homogen then pressing into to the dumbbell form molding. For epoxy matrix, pressing was done in hot press at 70 deg. C and 150 kg/cm 2 following by cooling in cold press, while for polyester matrix pressing was done in hydraulic press and following by curing at 70 deg. C in an oven for 1 hour. The composition of magnetic powder were varied to 30, 40 and 50% volume fraction and coupling agent were varied to 5, 10 and 15 ml for every volume fraction. The result showed that 10 ml added of coupling agent was give best mechanical properties both polyester and epoxy matrix. However generally, increasing of magnetic powder content decreased the tensile strength of magnetic composite. The properties of magnetic composite SrM was better than BaM either in polyester or epoxy matrix

A solvent induced crystallisation method to imbue bioactive ingredients of neem oil into the compact structure of poly (ethylene terephthalate) polyester

Energy Technology Data Exchange (ETDEWEB)

Ali, Wazed [Department of Textile Technology, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Sultana, Parveen [Department of Physics, Jadavpur University, Kolkata 700032 (India); Joshi, Mangala [Department of Textile Technology, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India); Rajendran, Subbiyan, E-mail: sr2@bolton.ac.uk [Institute for Materials Research and Innovation, The University of Bolton, Bolton BL3 5AB (United Kingdom)

2016-07-01

Neem oil, a natural antibacterial agent from neem tree (Azadarichtaindica) has been used to impart antibacterial activity to polyester fabrics. Solvent induced polymer modification method was used and that facilitated the easy entry of neem molecules into the compact structure of polyethylene terephthalate (PET) polyester. The polyester fabric was treated with trichloroacetic acid-methylene chloride (TCAMC) solvent system at room temperature prior to treatment with neem oil. The concentration of TCAMC and the treatment time were optimised. XRD and SEM results showed that the TCAMC treatment causes polymer modification and morphological changes in the PET polyester. Antibacterial activity of TCAMC pre-treated and neem-oil-treated polyester fabric was tested using AATCC qualitative and quantitative methods. Both Gram-positive and Gram-negative organisms were used to determine the antimicrobial activity. It was observed that the treated fabric registers substantial antimicrobial activity against both the Staphylococcus aureus (Gram-positive) and the Escherichia coli (Gram-negative) and the effect increases with the increase in concentration of TCAMC treatment. The antibacterial effect remains substantial even after 25 launderings. A kinetic growth study involving the effect of antibacterial activity at various incubation times was carried out. - Highlights: • A novel technique whereby the antibacterial components of neem oil are imbued into the compact structure of PET polyester • Trichloroacetic acid-Methylene Chloride treatment facilitated the easy entry of neem ingredients into the PET structure • Neem oil treated PET registered substantial antibacterial efficacy • Antibacterial effect is retained even after multiple use-wash cycles.

Effect of fiber content on tensile retention properties of Cellulose Microfiber Reinforced Polymer Composites for Automobile Application

Science.gov (United States)

Aseer, J. R.; Sankaranarayanasamy, K.

2017-12-01

Today, the utilization of biodegradable materials has been hogging much attention throughout the world. Due to the disposal issues of petroleum based products, there is a focus towards developing biocomposites with superior mechanical properties and degradation rate. In this research work, Hibiscus Sabdariffa (HS) fibers were used as the reinforcement for making biocomposites. The HS fibers were reinforced in the polyester resin by compression moulding method. Water absorption studies of the composite at room temperature are carried out as per ASTM D 570. Also, degradation behavior of HS/Polyester was done by soil burial method. The HS/polyester biocomposites containing 7.5 wt% of HS fiber has shown higher value of tensile strength. The tensile strength retention of the HS/Polyester composites are higher than the neat polyester composites. This value increases with increase of HS fiber loading in the composites. The results indicated that HS/polyester biocomposites can be used for making automobile components such as bumper guards etc.

Azobenzene Polyesters Used as Gate‐Like Scaffolds in Nanoscopic Hybrid Systems

DEFF Research Database (Denmark)

Bernardos, Andrea; Mondragón, Laura; Javakhishvili, Irakli

2012-01-01

inside the mesopores. Two solid materials, Rh‐PAzo8‐S and Rh‐PAzo6‐S, containing two closely related polymers, PAzo8 and PAzo6, in the pore outlets have been prepared. Materials Rh‐PAzo8‐S and Rh‐PAzo6‐S showed an almost zero release in water due to steric hindrance imposed by the presence of anchored...... bulky polyesters, whereas a large delivery of the cargo was observed in the presence of an esterase enzyme due to the progressive hydrolysis of polyester chains. Moreover, nanoparticles Rh‐PAzo8‐S and Rh‐PAzo6‐S were used to study the controlled release of the dye in intracellular media. Nanoparticles...... were not toxic for HeLa cells and endocytosis‐mediated cell internalisation was confirmed by confocal microscopy. Furthermore, the possible use of capped materials as a drug‐delivery system was demonstrated by the preparation of a new mesoporous silica nanoparticle functionalised with PAzo6 and loaded...

Chemical and enzymatic catalytic routes to polyesters and oligopeptides biobased materials

Science.gov (United States)

Zhu, Jianhui

My Ph.D research focuses on the synthesis and property studies of different biobased materials, including polyesters, polyurethanes and oligopeptides. The first study describes the synthesis, crystal structure and physico-mechanical properties of a bio-based polyester prepared from 2,5-furandicarboxylic acid (FDCA) and 1,4-butanediol. Melt-polycondensation experiments were conducted by a two-stage polymerization using titanium tetraisopropoxide (Ti[OiPr] 4) as catalyst. Polymerization conditions (catalyst concentration, reaction time and 2nd stage reaction temperature) were varied to optimize poly(butylene furan dicarboxylate), PBF, molecular weight. A series of PBFs with different Mw were characterized by Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Dynamic Mechanical Thermal Analysis (DMTA), X-Ray diffraction and tensile testing. Influence of molecular weight and melting/crystallization enthalpy on PBF material tensile properties was explored. Cold-drawing tensile tests at room temperature for PBF with Mw 16K to 27K showed a brittle-to-ductile transition. When Mw reaches 38K, the Young's Modulus of PBF remains above 900 MPa, and the elongation at break increases to above 1000%. The mechanical properties, thermal properties and crystal structures of PBF were similar to petroleum derived poly(butylenes terephthalate), PBT. Fiber diagrams of uniaxially stretched PBF films were collected, indexed, and the unit cell was determined as triclinic (a=4.78(3) A, b=6.03(5) A, c=12.3(1) A, alpha=110.1(2)°, beta=121.1(3)°, gamma=100.6(2)°). A crystal structure was derived from this data and final atomic coordinates are reported. We concluded that there is a close similarity of the PBF structure to PBT alpha- and beta-forms. In the second study, a biobased long chain polyester polyol (PC14-OH) was synthesized from o-hydroxytetradecanoic acid (o-HOC14) and 1,4-butanediol. The first section about polyester polyurethanes describes the synthesis

Ultrasound enhanced plasma treatment of glass-fibre-reinforced polyester in atmospheric pressure air for adhesion improvement

DEFF Research Database (Denmark)

Kusano, Yukihiro; Singh, Shailendra Vikram; Norrman, Kion

2011-01-01

A glass-fibre-reinforced polyester (GFRP) plate was treated with dielectric barrier discharge (DBD) at atmospheric pressure in air for adhesion improvement. The effects of ultrasonic irradiation using a high-power gas-jet generator during the treatment were investigated. The optical emission...... damage of the GFRP plates. The polar component of the surface energy of the polyester plate was 21 mJ/m2 before the treatment, increased markedly to 52 mJ/m2 after 2-s plasma treatment without ultrasonic irradiation, and further increased slightly after longer treatments. In addition, the polar component...

Biodegradable Sonobuoy Decelerators

Science.gov (United States)

2015-06-01

of Water Temperature and the Presence of Salt on the Disintegration Time of MonoSol A200 PVOH...polyhydroxyalkanoate (PHA). The proposed film would disintegrate , dissolve, and eventually biodegrade to prevent long-term effects on marine life. Ensuring no...Standard Specification for Non-Floating Biodegradable Plastics in the Marine Environment. Results showed that no PHA grades were toxic to the marine

Filler Fraction Effect on Creep Response of Crosslinked Polyester Matrix with Mineral Filler

Czech Academy of Sciences Publication Activity Database

Hristova, J.; Minster, Jiří

Vol. 89, - (2003), s. 3329-3335 ISSN 0021-8995 Institutional research plan: CEZ:AV0Z2071913 Keywords : polyester composites * creep * ageing Subject RIV: JI - Composite Materials Impact factor: 1.017, year: 2003

Highly Branched Bio-Based Unsaturated Polyesters by Enzymatic Polymerization

DEFF Research Database (Denmark)

Nguyen, Hiep Dinh; Löf, David; Hvilsted, Søren

2016-01-01

A one-pot, enzyme-catalyzed bulk polymerization method for direct production of highly branched polyesters has been developed as an alternative to currently used industrial procedures. Bio-based feed components in the form of glycerol, pentaerythritol, azelaic acid, and tall oil fatty acid (TOFA)...... stability, very high water contact angles of up to 141° and a glass transition temperature that could be controlled through the feed composition....

Side-chain liquid-crystalline polyesters for optical information storage

DEFF Research Database (Denmark)

Hvilsted, Søren; Andruzzi, F.; Ramanujam, P.S.

1992-01-01

We report erasable holographic recording with a resolution of at least 2500 lines/mm on unoriented films of side-chain liquid-crystalline polyesters. Recording energies of approximately 1 J/cm2 have been used. We have obtained a diffraction efficiency of approximately 30% with polarization record...... recording of holograms. The holograms can be erased by heating them to approximately 80-degrees-C for approximately 2 min and are available for rerecording....

The EIS investigation of powder polyester coatings on phosphated low carbon steel: The effect of NaNO2 in the phosphating bath

International Nuclear Information System (INIS)

Jegdic, B.V.; Bajat, J.B.; Popic, J.P.; Stevanovic, S.I.; Miskovic-Stankovic, V.B.

2011-01-01

Highlights: → The effect of NaNO 2 on surface morphology of iron-phosphate coatings were determined. → Better corrosion stability of polyester coating on phosphated steel without NaNO 2 . → EIS results and microscopic examinations correlate well with adhesion measurements. - Abstract: The effect of different type of iron-phosphate coatings on corrosion stability and adhesion characteristic of top powder polyester coating on steel was investigated. Iron-phosphate coatings were deposited on steel in the novel phosphating bath with or without NaNO 2 as an accelerator. The corrosion stability of the powder polyester coating was evaluated by electrochemical impedance spectroscopy (EIS), adhesion by pull-off and NMP test, while surface morphology of phosphate coatings were investigated by atomic force microscopy (AFM). The adhesion and corrosion stability of powder polyester coatings were improved with pretreatment based on iron-phosphate coating deposited from NaNO 2 -free bath.

Histological evaluation of different biodegradable and non-biodegradable membranes implanted subcutaneously in rats

DEFF Research Database (Denmark)

Zhao, S; Pinholt, E M; Madsen, J E

2000-01-01

Different types of biodegradable membranes have become available for guided tissue regeneration. The purpose of this study was to evaluate histologically three different biodegradable membranes (Bio-Gide, Resolut and Vicryl) and one non-biodegradable membrane (expanded polytetrafluoroethylene/e-PTFE...... that e-PTFE was well tolerated and encapsulated by a fibrous connective tissue capsule. There was capsule formation around Resolut and Vicryl and around Bio-Gide in the early phase there was a wide inflammatory zone already. e-PTFE and Vicryl were stable materials while Resolut and Bio-Gide fragmented...

Effect of polyester fiber reinforcement on the mechanical properties of interim fixed partial dentures

Directory of Open Access Journals (Sweden)

N. Gopichander

2015-10-01

Conclusion: Within the limitations of this study, polyester fiber reinforcements improved the mechanical properties of heat-polymerized PMMA, cold-polymerized PMMA, and bis-acrylic provisional FPD materials.

Purification and Properties of a Polyester Polyurethane-Degrading Enzyme from Comamonas acidovorans TB-35.

Science.gov (United States)

Akutsu, Y; Nakajima-Kambe, T; Nomura, N; Nakahara, T

1998-01-01

A polyester polyurethane (PUR)-degrading enzyme, PUR esterase, derived from Comamonas acidovorans TB-35, a bacterium that utilizes polyester PUR as the sole carbon source, was purified until it showed a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This enzyme was bound to the cell surface and was extracted by addition of 0.2% N,N-bis(3-d-gluconamidopropyl)deoxycholamide (deoxy-BIGCHAP). The results of gel filtration and SDS-PAGE showed that the PUR esterase was a monomer with a molecular mass of about 62,000 Da. This enzyme, which is a kind of esterase, degraded solid polyester PUR, with diethylene glycol and adipic acid released as the degradation products. The optimum pH for this enzyme was 6.5, and the optimum temperature was 45 degrees C. PUR degradation by the PUR esterase was strongly inhibited by the addition of 0.04% deoxy-BIGCHAP. On the other hand, deoxy-BIGCHAP did not inhibit the activity when p-nitrophenyl acetate, a water-soluble compound, was used as a substrate. These observations indicated that this enzyme degrades PUR in a two-step reaction: hydrophobic adsorption to the PUR surface and hydrolysis of the ester bond of PUR.

Characterization of a Bio-Based, Biodegradable Class of Copolymers, Poly[(R)-3-Hydroxybutyrate-Co-(R)-3- Hydroxyhexanoate], and Application Development

Science.gov (United States)

Sobieski, Brian

As modern society begins to focus on sustainability and renewable resources there is a growing need for the polymer industry to develop more environmentally friendly materials and practices. Part of this movement can be seen in the use of recycled materials in new products and in the development of bio-based, biodegradable polymers. Bio-based, biodegradable polymers are produced from renewable carbon sources, such as vegetable oils, typically polymerized using fermentation reactions via bacteria, and are able to be consumed by bacteria in landfills to completely convert the polymers to water and CO2. One class of such polymers are poly(hydroxyalkanoate)'s (PHAs), which are chiral, aliphatic polyesters. Within this class of polyesters are poly(hydroxybutyrate) (PHB) and the copolymer poly[(R)-3-hydroxybutyrate- co-(R)-3-hydroxyhexanoate] (PHBHx), which have received extensive study due to their material properties as thermoplastics. Although the properties of PHB have been widely explored, much still remains to be understood about these promising biodegradable polymers. Specifically, PHB and its copolymers exhibit physical gelation in most solvents, yet the origin and mechanism of gelation and the properties of the resulting gel state are unknown. This research effort was primarily focused on investigating the physical gel state of PHBHx. Five goals were laid out and completed: determining the origin of gelation, the mechanism of gelation, the structure of the gel state, the properties of the gel state, and the effects of gelation on electrospun fibers of PHBHx. These goals were achieved through material characterization of the gel state utilizing infrared spectroscopy/two-dimensional correlation spectroscopy, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and many other analysis methods. Crystallization of the polymer in solution was found to cause gelation in PHBHx solutions, where the polymer crystals act as tie points forming

Synthesis and characterization of polyester copolymers based on poly(butylene succinate) and poly(ethylene glycol)

International Nuclear Information System (INIS)

Zhou, Xiao-Ming

2012-01-01

A series of polyester copolymers was synthesized from 1,4-succinic acid with 1,4-butanediol and poly(ethylene glycol) through a two-step process of esterification and polycondensation in this article. The composition and physical properties of copolyesters were investigated via GPC, 1 HNMR, DSC and PLM. The copolymer composition was in good agreement with that expected from the feed composition of the reactants. The melting temperature (T m ), crystallization temperature (T c ), and crystallinity (X c ) of these copolyesters decreased gradually as the content of PEG unit increased. Otherwise, experimental results also showed that the contents of PEG in copolymers had an effect on the molecular weight, distribution, thermal properties, hydrolysis degradation properties, and crystalline morphology of polyester copolymers. - Graphical abstract: The composition of polyester copolymer was determined from the 1 H NMR spectra using the relative intensities of the proton peaks. As a sample, the 1 H NMR spectrum of polyester copolymer with 10 mol% of PEG is shown in Fig. 2: CO-(CH 2 ) 2 -CO; O-CH 2 - and C-(CH 2 ) 2 -C from the SA and BD unit at δ2.59; δ 4.08 and δ1.67; O-(CH 2 CH 2 ) n -O from the PEG unit at δ 3.61. The molar composition of polyester copolymer was measured as the area ratio of δ3.61/(δ4.08 + δ1.67) peak. The PEG unit is incorporated into the copolymers in an amount of about 9.12mol% less than that of the feed proportion. These results showed that the composition of the copolymers is in good agreement with that expected from the feed proportion. Highlights: ► The introduction of PEG unit changed the flexibility of PBS main chain. ► PEG unit did not alter the crystal form of PBS in copolymers. ► PEG unit hindered the formation of ring-banded spherulite morphology in copolymers. ► The copolyesters had good in vitro degradation performance. ► The composition ratio of PEG unit can adjust the in vitro degradation performance.

Biodegradable modified Phba systems

International Nuclear Information System (INIS)

Aniscenko, L.; Dzenis, M.; Erkske, D.; Tupureina, V.; Savenkova, L.; Muizniece - Braslava, S.

2004-01-01

Compositions as well as production technology of ecologically sound biodegradable multicomponent polymer systems were developed. Our objective was to design some bio plastic based composites with required mechanical properties and biodegradability intended for use as biodegradable packaging. Significant characteristics required for food packaging such as barrier properties (water and oxygen permeability) and influence of γ-radiation on the structure and changes of main characteristics of some modified PHB matrices was evaluated. It was found that barrier properties were plasticizers chemical nature and sterilization with γ-radiation dependent and were comparable with corresponding values of typical polymeric packaging films. Low γ-radiation levels (25 kGy) can be recommended as an effective sterilization method of PHB based packaging materials. Purposely designed bio plastic packaging may provide an alternative to traditional synthetic packaging materials without reducing the comfort of the end-user due to specific qualities of PHB - biodegradability, Biocompatibility and hydrophobic nature

Diffraction from polarization holographic gratings with surface relief in side-chain azobenzene polyesters

DEFF Research Database (Denmark)

Naydenova, I; Nikolova, L; Todorov, T

1998-01-01

We investigate the polarization properties of holographic gratings in side-chain azobenzene polyesters in which an anisotropic grating that is due to photoinduced linear and circular birefringence is recorded in the volume of the material and a relief grating appears on the surface. A theoretical...... model is proposed to explain the experimental results, making it possible to understand the influence of the different photoinduced effects. It is shown that at low intensity the polarization properties of the diffraction at these gratings are determined by the interaction of the linear and circular...... photobirefringences, and at larger intensity the influence of the surface relief dominates the effect of the circular anisotropy. Owing to the high recording efficiency of the polyesters, the +/-1-order diffracted waves change the polarization interference pattern during the holographic recording, resulting...

Current knowledge on biodegradable microspheres in drug delivery.

Science.gov (United States)

Prajapati, Vipul D; Jani, Girish K; Kapadia, Jinita R

2015-08-01

Biodegradable microspheres have gained popularity for delivering a wide variety of molecules via various routes. These types of products have been prepared using various natural and synthetic biodegradable polymers through suitable techniques for desired delivery of various challenging molecules. Selection of biodegradable polymers and technique play a key role in desired drug delivery. This review describes an overview of the fundamental knowledge and status of biodegradable microspheres in effective delivery of various molecules via desired routes with consideration of outlines of various compendial and non-compendial biodegradable polymers, formulation techniques and release mechanism of microspheres, patents and commercial biodegradable microspheres. There are various advantages of using biodegradable polymers including promise of development with different types of molecules. Biocompatibility, low dosage and reduced side effects are some reasons why usage biodegradable microspheres have gained in popularity. Selection of biodegradable polymers and formulation techniques to create microspheres is the biggest challenge in research. In the near future, biodegradable microspheres will become the eco-friendly product for drug delivery of various genes, hormones, proteins and peptides at specific site of body for desired periods of time.

Absorbable Polydioxanone (PDS) suture provides fewer wound complications than polyester (ethibond) suture in acute Tendo-Achilles rupture repair

LENUS (Irish Health Repository)

Baig, M N

2017-05-01

We prospectively studied acute Achilles tendon rupture in patients over a two 2-year period and reviewed the causes, outcome and complications. There were 53 patients included with acute Achilles rupture with minimum follow up period of 6 months. We compared the outcomes including infection rate and Boyden score between the two groups repaired by Polydioxanone and Polyester respectively. All infected cases had a suture repair using the polyester suture. The difference in the infection rate was highly significant between the 2 groups (p=0.001). All 34 patients (100%) in the PDS group had good \\/ excellent results based on the Boyden clinical assessment. Conversely, only 16 patients 9(68.4%) had good or excellent results IN Polyester repair group. Patients treated with a non- absorbable suture (ethibond) material for repair had a higher incidence infection and worse Boyden scores than the absorbable PDS group.

UV-irradiation effects on polyester nuclear track detector

International Nuclear Information System (INIS)

Agarwal, Chhavi; Kalsi, P.C.

2010-01-01

The effects of UV irradiation (λ=254 nm) on polyester nuclear track detector have been investigated employing bulk-etch technique, UV-visible spectrophotometry and infra-red spectrometry (FTIR). The activation energy values for bulk-etching were found to decrease with the UV-irradiation time indicating the scission of the polymer. Not much shift in the absorption edge due to UV irradiation was seen in the UV-visible spectra. FTIR studies also indicate the scission of the chemical bonds, thereby further validating the bulk-etch rate results.

Poly(Butylene Succinate) and Poly[(Butylene Succinate)-co-Adipate] Nanocomposites

CSIR Research Space (South Africa)

Ojijo, Vincent O

2012-01-01

Full Text Available In the recent years, biodegradable aliphatic polyesters-based composite materials have attracted substantial interest, primarily due to their sustainable production, use and end-life. This chapter discusses the preparation, characterisation...

Plasma Surface Modification of Glass-Fibre-Reinforced Polyester Enhanced by Ultrasonic Irradiation

DEFF Research Database (Denmark)

Kusano, Yukihiro; Singh, Shailendra Vikram; Bardenshtein, Alexander

2010-01-01

treatment can be highly enhanced by simultaneous high-power ultrasonic irradiation of the treating surface, because the delivered acoustic energy can reduce the thickness of the boundary gas layer. Here surfaces of glass-fibre-reinforced polyester (GFRP) plates were treated using an atmospheric pressure...

Thermoplastic poly(urethane urea)s from novel, bio-based amorphous polyester diols

NARCIS (Netherlands)

Tang, D.; Noordover, B.A.J.; Sablong, R.J.; Koning, C.E.

2012-01-01

In this study, two novel, bio-based, amorphous polyester diols, namely poly(1,2-dimethylethylene adipate) (PDMEA) and poly(1,2-dimethylethylene succinate) (PDMES) are used to prepare thermoplastic poly(urethane urea)s (TPUUs). Interestingly, the TPUUs based on PDMEA show similar thermal and

The effect of oxidation on the enzyme-catalyzed hydrolytic biodegradation of poly(urethane)s.

Science.gov (United States)

Labow, Rosalind S; Tang, Yiwen; McCloskey, Christopher B; Santerre, J Paul

2002-01-01

Although the biodegradation of polyurethanes (PU) by oxidative and hydrolytic agents has been studied extensively, few investigations have reported on the combination of their effects. Since neutrophils (PMN) arrive at an implanted device first and release HOCl, followed by monocyte-derived macrophages (MDM) which have potent esterase activities and oxidants of their own, the combined effect of oxidative and hydrolytic degradation on radiolabeled polycarbonate-polyurethanes (PCNU)s was investigated and compared to that of a polyester-PU (PESU) and a polyether-PU (PEU). The PCNUs were synthesized with PCN (MW = 1,000), and butanediol (14C-BD) and one of two diisocyanates, hexane-1,6-diisocyanate (14C-HDI) or methylene bis-p-phenyl diisocyanate (MDI). The PESU and PEU were synthesized using toluene-diisocyanate (14C-TDI), with polycaprolactone and polytetramethylene oxide as soft segments respectively, and ethylene diamine as the chain extender. The effect of pre-treatment with 0.1 mM HOC1 for 1 week on the HDI-based PCNUs and both TDI-based PUs resulted in a significant inhibition of radiolabel release (RR) elicited by cholesterol esterase (CE), when compared to buffer alone, whereas the MDI-based PCNU showed a small but significant increase. When PMN were activated on the HDI-based PCNU surface with phorbol myristate acetate (PMA), HOCl was released for 3 h, and was almost completely abolished by sodium azide (AZ). Simultaneously, the PMN-elicited RR, shown previously to be due to the esterolytic cleavage by serine proteases, was inhibited approximately 75% by PMA-activation of the cells, but significantly increased relative to the latter when AZ was added. Both in vitro oxidation by HOCl and the release of HOCI by PMN were associated with the inhibition of RR and suggest perturbations between oxidative and hydrolytic mechanisms of biodegradation.

Fully Biobased Unsaturated Aliphatic Polyesters from Renewable Resources : Enzymatic Synthesis, Characterization, and Properties

NARCIS (Netherlands)

Jiang, Yi; Alberda van Ekenstein, Gerhard; Woortman, Albert J. J.; Loos, Katja

2014-01-01

Fully biobased saturated and unsaturated aliphatic polyesters and oligoesters are successfully prepared by Candida antarctica lipase B (CALB)-catalyzed polycondensations of succinate, itaconate, and 1,4-butanediol. The effects of monomer substrates and polymerization methods on enzymatic

Biochemical interpretation of quantitative structure-activity relationships (QSAR) for biodegradation of N-heterocycles: a complementary approach to predict biodegradability.

Science.gov (United States)

Philipp, Bodo; Hoff, Malte; Germa, Florence; Schink, Bernhard; Beimborn, Dieter; Mersch-Sundermann, Volker

2007-02-15

Prediction of the biodegradability of organic compounds is an ecologically desirable and economically feasible tool for estimating the environmental fate of chemicals. We combined quantitative structure-activity relationships (QSAR) with the systematic collection of biochemical knowledge to establish rules for the prediction of aerobic biodegradation of N-heterocycles. Validated biodegradation data of 194 N-heterocyclic compounds were analyzed using the MULTICASE-method which delivered two QSAR models based on 17 activating (OSAR 1) and on 16 inactivating molecular fragments (GSAR 2), which were statistically significantly linked to efficient or poor biodegradability, respectively. The percentages of correct classifications were over 99% for both models, and cross-validation resulted in 67.9% (GSAR 1) and 70.4% (OSAR 2) correct predictions. Biochemical interpretation of the activating and inactivating characteristics of the molecular fragments delivered plausible mechanistic interpretations and enabled us to establish the following biodegradation rules: (1) Target sites for amidohydrolases and for cytochrome P450 monooxygenases enhance biodegradation of nonaromatic N-heterocycles. (2) Target sites for molybdenum hydroxylases enhance biodegradation of aromatic N-heterocycles. (3) Target sites for hydratation by an urocanase-like mechanism enhance biodegradation of imidazoles. Our complementary approach represents a feasible strategy for generating concrete rules for the prediction of biodegradability of organic compounds.

Radiation-induced changes affecting polyester based polyurethane binder

Science.gov (United States)

Pierpoint, Sujita Basi

The application of thermoplastic polyurethane elastomers as binders in the high energy explosives particularly when used in weapons presents a significantly complex and challenging problem due to the impact of the aging of this polymer on the useful service life of the explosive. In this work, the effects of radiation on the aging of the polyester based polyurethane were investigated using both electron beam and gamma irradiation at various dose rates in the presence and absence of oxygen. It was found by means of GPC that, in the presence and absence of oxygen, the poly (ester urethane) primarily undergoes cross-linking, by means of a carbon-centered secondary alkyl radical. It was also concluded that the polymer partially undergoes scission of the backbone of the main chain at C-O, N-C, and C-C bonds. Substantial changes in the conditions of irradiation and in dose levels did not affect the cross-linking and scission yields. Experiments were also performed with EPR spectroscopy for the purpose of identifying the initial carbon-centered free radicals and for studying the decay mechanisms of these radicals. It was found that the carbon-centered radical which is produced via C-C scission (primary alkyl radical) is rapidly converted to a long-lived allylic species at higher temperatures; more than 80% radicals are converted to allyl species in 2.5 hours. In the presence of oxygen, the allyl radical undergoes a fast reaction to produce a peroxyl radical; this radical decays with a 1.7 hour half-life by pseudo first-order kinetics to negligible levels in 13 hours. FTIR measurements were conducted to identify the radiation-induced changes to the functional groups in the polyester polyurethane. These measurements show an increase in carbonyl, amine and carboxylic groups as a result of reaction of H atoms with R-C-O·, ·NH-R and R-COO·. The FTIR results also demonstrate the production of the unsaturation resulting from hydrogen atom transfer during intrachain conversion

Unsaturated polyester resin composition curable with ionizing radiations

International Nuclear Information System (INIS)

Maruyama, Tsutomu; Murata, Koichiro.

1971-01-01

An unsaturated polyester resin composition curable with ionizing radiations and excellent in weather resistance is provided. The composition is obtained by reacting 10-12 moles of a polyhydric alcohol (e.g. ethylene glycol) with 10 moles of an acid mixture (25.45% by mole of endo-cis-bicyclo (2,2,1)-5-heptene-2-3-dicarboxylic acid (A), 20-40% of unsaturated dibasic acid and 15-55% of saturated dibasic acid) so that the acid value reaches 4-11. The composition is useful as coating, laminating and molding materials. As a coating material it is excellent in surface hardening property. The ionizing radiation used is preferably β-, α-rays or electron beams. In one example, and unsaturated polyester was prepared by reacting 3 moles of fumaric acid, 2 moles of phthalic anhydride, 3 moles of adipic acid 3, moles of (A), 10 moles of neopentyl glycol and 1 mole of trimethylolpropane. The resin was dissolved into a mixture of styrene, methyl methacrylate and butyl acrylate (50:8:42) and incorporated with titanium white. An ABS plate was coated with the enamel thus obtained and irradiated with electron beams (12 Mrad). In exposure test at 60 0 C, luster of the film was 92 before exposure and 83 after 30 months. In a comparative run in which (A) was not used, luster of the film decreased from 90 to 45 in 30 months. (Sakaichi, S.)

Research of the biodegradability of degradable/biodegradable plastic material in various types of environments

Directory of Open Access Journals (Sweden)

Dana Adamcová

2017-04-01

Full Text Available Research was carried out in order to assess biodegradability of degradable/biodegradable materials made of HDPE and mixed with totally degradable plastic additive (TDPA additive or made of polyethylene (PE with the addition of pro-oxidant additive (d2w additive, advertised as 100% degradable or certifi ed as compostable within various types of environments. Research conditions were: (i controlled composting environment – laboratory-scale, (ii real composting conditions – domestic compost bin, (iii real composting conditions – industrial composting plant and (iv landfill conditions. The results demonstrate that the materials made of HDPE and mixed with totally degradable plastic additive (TDPA additive or made of polyethylene (PE with the addition of pro-oxidant additive (d2w additive or advertised as 100% degradable did not biodegrade in any of the above-described conditions and remained completely intact at the end of the tests. Biodegradation of the certified compostable plastic bags proceeded very well in laboratory-scale conditions and in real composting conditions – industrial composting plant, however, these materials did not biodegrade in real composting conditions – domestic compost bin and landfill conditions.

Biodegradation of bioplastics in natural environments.

Science.gov (United States)

Emadian, S Mehdi; Onay, Turgut T; Demirel, Burak

2017-01-01

The extensive production of conventional plastics and their use in different commercial applications poses a significant threat to both the fossil fuels sources and the environment. Alternatives called bioplastics evolved during development of renewable resources. Utilizing renewable resources like agricultural wastes (instead of petroleum sources) and their biodegradability in different environments enabled these polymers to be more easily acceptable than the conventional plastics. The biodegradability of bioplastics is highly affected by their physical and chemical structure. On the other hand, the environment in which they are located, plays a crucial role in their biodegradation. This review highlights the recent findings attributed to the biodegradation of bioplastics in various environments, environmental conditions, degree of biodegradation, including the identified bioplastic-degrading microorganisms from different microbial communities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modelling of polyester fabric dyeing in the presence of ultrasonic waves

Directory of Open Access Journals (Sweden)

Kodrić Marija

2017-01-01

Full Text Available In this paper, modelling of dyeing, i.e. adsorptive behaviour of disperse dyes on polyester fibres (dyeing, under the influence of ultrasound has been considered with the aim of getting the data about mechanisms of binding the dyes and defining the conditions of dyeing process of this synthetic fibres along with additional energy source without the use of carriers, compounds that increase permeability of the fibres and help dyeing. Dyeing - adsorption is conducted under different conditions, and the concentration of dyes, mass of the substrate, recipes and time of dyeing were being varied. It has been established that ultrasound allows dyeing without carriers and the efficiency of dyeing depends on the time of contact, initial concentration of the dye and the amount of absorbent - material. There is the continuity of growth of the amount of bound dye to the mass of the absorbent. Characteristic graphs, obtained from Langmuir isotherm, have confirmed that this model ensures precise description of polyester dyeing by disperse dye. Kinetic of dyeing has been remarkably interpreted by pseudo second-order in regards to the high functionality.

Structural and Functional Studies of A. oryzae Cutinase: Enhanced Thermostability and Hydrolytic Activity of Synthetic Ester and Polyester Degradation

OpenAIRE

Liu, Zhiqiang; Gosser, Yuying; Baker, Peter James; Ravee, Yaniv; Lu, Ziying; Alemu, Girum; Li, Huiguang; Butterfoss, Glenn L.; Kong, Xiang-Peng; Gross, Richard; Montclare, Jin Kim

2009-01-01

Cutinases are responsible for hydrolysis of the protective cutin lipid polyester matrix in plants and thus have been exploited for hydrolysis of small molecule esters and polyesters. Here we explore the reactivity, stability, and structure of Aspergillus oryzae cutinase and compare it to the well-studied enzyme from Fusarium solani. Two critical differences are highlighted in the crystallographic analysis of the A. oryzae structure: (i) an additional disulfide bond and (ii) a topologically fa...

Electromagnetic shielding mechanisms using soft magnetic stainless steel fiber enabled polyester textiles

Science.gov (United States)

Shyr, Tien-Wei; Shie, Jing-Wen

2012-11-01

This work studied the effects of conductivity, magnetic loss, and complex permittivity when using blended textiles (SSF/PET) of polyester fibers (PET) with stainless steel fibers (SSF) on electromagnetic wave shielding mechanisms at electromagnetic wave frequencies ranging from 30 MHz to 1500 MHz. The 316L stainless steel fiber used in this study had 38 vol% γ austenite and 62 vol% α' martensite crystalline phases, which was characterized by an x-ray diffractometer. Due to the magnetic and dielectric loss of soft metallic magnetic stainless steel fiber enabled polyester textiles, the relationship between the reflection/absorption/transmission behaviors of the electromagnetic wave and the electrical/magnetic/dielectric properties of the SSF and SSF/PET fabrics was analyzed. Our results showed that the electromagnetic interference shielding of the SSF/PET textiles show an absorption-dominant mechanism, which attributed to the dielectric loss and the magnetic loss at a lower frequency and attributed to the magnetic loss at a higher frequency, respectively.

Biodegradation of flax fiber reinforced poly lactic acid

Directory of Open Access Journals (Sweden)

2010-07-01

Full Text Available Woven and nonwoven flax fiber reinforced poly lactic acid (PLA biocomposites were prepared with amphiphilic additives as accelerator for biodegradation. The prepared composites were buried in farmland soil for biodegradability studies. Loss in weight of the biodegraded composite samples was determined at different time intervals. The surface morphology of the biodegraded composites was studied with scanning electron microscope (SEM. Results indicated that in presence of mandelic acid, the composites showed accelerated biodegradation with 20–25% loss in weight after 50–60 days. On the other hand, in presence of dicumyl peroxide (as additive, biodegradation of the composites was relatively slow as confirmed by only 5–10% loss in weight even after 80–90 days. This was further confirmed by surface morphology of the biodegraded composites. We have attempted to show that depending on the end uses, we can add different amphiphilic additives for delayed or accelerated biodegradability. This work gives us the idea of biodegradation of materials from natural fiber reinforced PLA composites when discarded carelessly in the environment instead of proper waste disposal site.

A study on influence of borax to polyester insulators

OpenAIRE

ERSOY, Aysel; KUNTMAN, Ayten

2014-01-01

In this study the effect of borax on polyester insulators is investigated by evaluating the tracking and erosion resistance using the inclined plane test. The test procedure follows the ASTM D2303 standard. During the test, 50 Hz current was acquired from the ground electrode allowing a sampling rate of 48000 samples per second. The effect of borax concentration on the glass transition and the degradation temperature is studied by employing differential scanning calorimetry (DSC) an...

Preparation and characterization of metal complex hydrogels crosslinked with hyperbranched polyester

Czech Academy of Sciences Publication Activity Database

Haroun, A. A.; Hakeim, O. A.; Trhlíková, Olga; Šlouf, Miroslav; Netopilík, Miloš

2017-01-01

Roč. 60, č. 5 (2017), s. 849-856 ISSN 0449-2285 R&D Projects: GA ČR(CZ) GC17-04258J Grant - others:AV ČR(CZ) ASRT-16-02 Program:Bilaterální spolupráce Institutional support: RVO:61389013 Keywords : hyperbranched polyester * chitosan * miniemulsion Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science

Gliding arc discharge — Application for adhesion improvement of fibre reinforced polyester composites

DEFF Research Database (Denmark)

Kusano, Yukihiro; Teodoru, Steluta; Leipold, Frank

2008-01-01

production, and surface treatment. However, the application for adhesion improvement of structural materials has been rarely reported. In the present work, glass fibre reinforced polyester plates were treated using atmospheric pressure gliding arcs with high speed air flow for adhesion improvement...

Dynamic mechanical and dielectric behavior of banana–glass hybrid fiber reinforced polyester composites.

CSIR Research Space (South Africa)

Pothan, LA

2009-01-01

Full Text Available Hybrid composites of glass and banana fiber (obtained from the pseudo stem of Musa sapientum) in polyester matrix, are subjected to dynamic mechanical analysis over a range of temperature and three different frequencies. The effect of temperature...

Biodegradable micromechanical sensors

DEFF Research Database (Denmark)

Keller, Stephan Sylvest; Greve, Anders; Schmid, Silvan

of mechanical and thermal properties of polymers. For example, measurements of the resonance frequency of cantilevers were used to characterize thin polymer coatings in various environmental conditions [2]. Also, the influence of humidity on the Young’s modulus of SU-8 was evaluated [3]. However, introduction...... (NIL). Second, we used spray-coating to deposit thin biodegradable films on microcantilevers. Both approaches allowed the determination of the Young’s modulus of the biopolymer. Furthermore, biodegradation by enzymes was investigated....

Transport behavior of n-alkane penetrants into castor oil based polyurethane-polyester nonwoven fabric composites

International Nuclear Information System (INIS)

Satheesh Kumar, M.N.; Manjula, K.S.; Siddaramaiah

2007-01-01

Castor oil based polyurethane (PU)-polyester nonwoven fabric composites were fabricated by impregnating the polyester nonwoven fabric in a composition containing castor oil and diisocyanate. Composites were fabricated with two different isocyanates such as toluene-2,4-diisocyanate (TDI) and hexamethylene diisocyanate (HMDI). Transport behavior of n-alkane penetrants (pentane, hexane and heptane) into both PUs and PU-polyester nonwoven fabric composites were studied. Sorption studies were carried out at different temperatures. From the sorption results, the diffusion (D) and permeation (P) coefficients of penetrants have been calculated. Significant increase in the diffusion and permeation coefficients was observed with increase in the temperature of sorption experiments. Drastical reduction in diffusion and permeation coefficients was noticed in the composites compared to neat PUs. Attempts were made to estimate the empirical parameters like n, which suggests the mode of transport and K is a constant depends on the structural characteristics of the composite in addition to its interaction with penetrants. The temperature dependence of the transport coefficients has been used to estimate the activation energy parameter for diffusion (E D ) and permeation (E P ) processes from Arrhenius plots. Furthermore, the sorption results have been interpreted in terms of the thermodynamic parameters such as enthalpy (ΔH) and entropy (ΔS)

Systemic approaches to biodegradation.

Science.gov (United States)

Trigo, Almudena; Valencia, Alfonso; Cases, Ildefonso

2009-01-01

Biodegradation, the ability of microorganisms to remove complex chemicals from the environment, is a multifaceted process in which many biotic and abiotic factors are implicated. The recent accumulation of knowledge about the biochemistry and genetics of the biodegradation process, and its categorization and formalization in structured databases, has recently opened the door to systems biology approaches, where the interactions of the involved parts are the main subject of study, and the system is analysed as a whole. The global analysis of the biodegradation metabolic network is beginning to produce knowledge about its structure, behaviour and evolution, such as its free-scale structure or its intrinsic robustness. Moreover, these approaches are also developing into useful tools such as predictors for compounds' degradability or the assisted design of artificial pathways. However, it is the environmental application of high-throughput technologies from the genomics, metagenomics, proteomics and metabolomics that harbours the most promising opportunities to understand the biodegradation process, and at the same time poses tremendous challenges from the data management and data mining point of view.

Biodegradation performance of environmentally-friendly insulating oil

Science.gov (United States)

Yang, Jun; He, Yan; Cai, Shengwei; Chen, Cheng; Wen, Gang; Wang, Feipeng; Fan, Fan; Wan, Chunxiang; Wu, Liya; Liu, Ruitong

2018-02-01

In this paper, biodegradation performance of rapeseed insulating oil (RDB) and FR3 insulating oil (FR3) was studied by means of ready biodegradation method which was performed with Organization for Economic Co-operation and Development (OECD) 301B. For comparison, the biodegradation behaviour of 25# mineral insulating oil was also characterized with the same method. The testing results shown that the biodegradation degree of rapeseed insulating oil, FR3 insulating oil and 25# mineral insulating oil was 95.8%, 98.9% and 38.4% respectively. Following the “new chemical risk assessment guidelines” (HJ/T 154 - 2004), which illustrates the methods used to identify and assess the process safety hazards inherent. The guidelines can draw that the two vegetable insulating oils, i.e. rapeseed insulating oil and FR3 insulating oil are easily biodegradable. Therefore, the both can be classified as environmentally-friendly insulating oil. As expected, 25# mineral insulating oil is hardly biodegradable. The main reason is that 25# mineral insulating oil consists of isoalkanes, cyclanes and a few arenes, which has few unsaturated bonds. Biodegradation of rapeseed insulating oil and FR3 insulating oil also remain some difference. Biodegradation mechanism of vegetable insulating oil was revealed from the perspective of hydrolysis kinetics.

Obtaining polyester from glycerin for synthesis of polyurethanes; Obtencao de poliester a partir da glicerina para sintese de poliuretanas

Energy Technology Data Exchange (ETDEWEB)

Breves, Rodolfo A.; Ghesti, Grace F.; Sales, Maria J.A., E-mail: eu_sou_o_rodolfo@hotmail.com [Universidade de Brasilia (LabPol/UnB), DF (Brazil). Laboratorio de Pesquisa em Polimeros; Silva, Jessica S.; Coelho, Paulo V.M.; Lopes, Roseany V.V. [Universidade de Brasilia (UnB), DF (Brazil). Faculdade do Gama; Brioude, Michel M. [Freiburg University (Germany)

2014-07-01

The use of renewable resources has been increasing, due to the development of materials that have viable applications that are environmentally friendly. In this paper, a polyester was synthesized from glycerin, with the addition of adipic acid in a molar ratio of 1: 1.5, with dilauryl tin catalyst, which was added in proportions of 1 to 3% obtained PUs from castor oil (Ricinus communis) and MDI (diphenyl methane diisocyanate). The materials were characterized by infrared spectroscopy (FTIR), nuclear magnetic resonance {sup 1}H NMR, thermogravimetry (TG) and derivative thermogravimetry (DTG). The reaction for obtaining the polyester was confirmed by FTIR, the absorption band between 1708-1730 cm{sup -1} and {sup 1}H NMR, in the region 1.4 to 1.8 ppm and 2.2 to 2.6 ppm. The thermal decomposition of polyester occurred with temperature above 300 ° C. PUs showed similar thermal stability. (author)

Synthesis of a novel polyester building block from pentoses by tin-containing silicates

DEFF Research Database (Denmark)

Elliot, Samuel Gilbert; Andersen, Christian; Tolborg, Søren

2017-01-01

a product containing functional groups originating from trans-2,5-dihydroxy-3-pentenoic acid methyl ester in the polyester backbone. The reactivity of the incorporated olefin and hydroxyl moieties was investigated using trifluoroacetic anhydride and thiol-ene chemisitry, thus illustrating the potential...

Development of a model for the synthesis of unsaturated polyester by reactive distillation

NARCIS (Netherlands)

Shah, M.R.; Zondervan, E.; Oudshoorn, M.L.; Haan, de A.B.; Haan, de A.B.; Kooijman, H.; Górak, A.

2010-01-01

Traditionally polyester production is done in a batch reactor equipped with a separation column for batch distillation. A promising alternative for the intensification of this process is reactive distillation. In this paper, a reactive distillation model is developed for the synthesis of an

Polyester composites reinforced with corona-treated fibers from pine, eucalyptus and sugarcane bagasse

Science.gov (United States)

This study aims to evaluate plant fibers that were surface activated with NaOH and corona discharge before incorporating in ortho unsaturated polyester-based fiber composites. It demonstrates the potential use of lignocellulosic particles, especially eucalyptus that presented the higher values for a...

Effect of sterilization dose on electron beam irradiated biodegradable polymers and coconut fiber based composites

Energy Technology Data Exchange (ETDEWEB)

Kodama, Yasko; Machado, Luci D.B., E-mail: ykodama@ipen.b, E-mail: lmachado@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Oishi, Akihiro; Nakayama, Kazuo, E-mail: a.oishi@aist.go.j, E-mail: kazuo-nakayama@jcom.home.ne.j [National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki-ken (Japan). Research Institute for Sustainable Chemical Innovation; Nagasawa, Naotsugu; Tamada, Masao, E-mail: nagasawa.naotsugu@jaea.go.j [Japan Atomic Energy Agency (JAEA), Gunma-ken (Japan). Quantum Beam Science Directorate

2009-07-01

In Brazil, annual production of coconut fruit is 1.5 billion in a cultivated area of 2.7 million ha. Coconut fiber applications as reinforcement for polymer composites, besides reducing the coconut waste, would reduce cost of the composite. On the other hand, biodegradable polymers have been receiving much attention due to the plastic waste problem. Poly(e-caprolactone), PCL, and poly(lactic acid), PLA, besides being biodegradable aliphatic polyesters, are biocompatible polymers. Considering the biomedical application of PLA and PCL, their products must be sterilized for use, and ionizing radiation has been widely used for medical devices sterilization. It is important to study the effect of ionizing radiation on the blends and composites due to the fact that they are based on biocompatible polymers. Is this research, hot pressed samples based on PLA:PCL (80:20, ratio of weight:weight) blend and the composites containing chemically treated or untreated coconut fiber (5, 10%) were irradiated by electron beams and gamma radiation from Co-60 source at doses in the range up to 200 kGy. Thermal mechanical analysis (TMA) and gel fraction measurements were performed in irradiated samples. From TMA curves it can be observed that thermal stability of samples with untreated coconut fiber slightly decreased with increasing fiber content. On the other hand, deformation increased with increasing fiber content. Acetylated coconut fibers slightly decreased thermal stability of samples. It seems that no interaction occurs between the natural fibers and the polymeric matrix due to irradiation. PLLA undergoes to main chain scission under ionizing irradiation according to thermal stability results and also because no gel fraction was observed. In contrast, PCL cross-linking is induced by ionizing radiation that increases thermal stability and decreases deformation. (author)

Effect of sterilization dose on electron beam irradiated biodegradable polymers and coconut fiber based composites

International Nuclear Information System (INIS)

Kodama, Yasko; Machado, Luci D.B.; Oishi, Akihiro; Nakayama, Kazuo; Nagasawa, Naotsugu; Tamada, Masao

2009-01-01

In Brazil, annual production of coconut fruit is 1.5 billion in a cultivated area of 2.7 million ha. Coconut fiber applications as reinforcement for polymer composites, besides reducing the coconut waste, would reduce cost of the composite. On the other hand, biodegradable polymers have been receiving much attention due to the plastic waste problem. Poly(e-caprolactone), PCL, and poly(lactic acid), PLA, besides being biodegradable aliphatic polyesters, are biocompatible polymers. Considering the biomedical application of PLA and PCL, their products must be sterilized for use, and ionizing radiation has been widely used for medical devices sterilization. It is important to study the effect of ionizing radiation on the blends and composites due to the fact that they are based on biocompatible polymers. Is this research, hot pressed samples based on PLA:PCL (80:20, ratio of weight:weight) blend and the composites containing chemically treated or untreated coconut fiber (5, 10%) were irradiated by electron beams and gamma radiation from Co-60 source at doses in the range up to 200 kGy. Thermal mechanical analysis (TMA) and gel fraction measurements were performed in irradiated samples. From TMA curves it can be observed that thermal stability of samples with untreated coconut fiber slightly decreased with increasing fiber content. On the other hand, deformation increased with increasing fiber content. Acetylated coconut fibers slightly decreased thermal stability of samples. It seems that no interaction occurs between the natural fibers and the polymeric matrix due to irradiation. PLLA undergoes to main chain scission under ionizing irradiation according to thermal stability results and also because no gel fraction was observed. In contrast, PCL cross-linking is induced by ionizing radiation that increases thermal stability and decreases deformation. (author)

Reduction in the body content of DDE in the Mongolian gerbil treated with sucrose polyester and caloric restriction

International Nuclear Information System (INIS)

Mutter, L.C.; Blanke, R.V.; Jandacek, R.J.; Guzelian, P.S.

1988-01-01

It has previously been shown that oral administration to rats of sucrose polyester (SPE4), a nonabsorbable lipophilic binding agent, greatly stimulates the fecal excretion of coorally administered DDT5. To determine whether this agent would stimulate the excretion of persistent metabolites of DDT stored in body tissues, we treated a group of gerbils with [ 14 C]-DDT and monitored the fecal excretion of radioactivity for several months until a terminal, log-linear phase of excretion was observed. At this point, when greater than 75% of the fecal radioactivity was identified as [ 14 C]DDE, we fed the animals diets containing up to 10% sucrose polyester and found that the rate of excretion of radioactivity in the stool promptly increased two to three times as compared to the rate in the preceding control period. Some rats were subjected to a 25-50% restriction in total food allotment, but this produced no significant change in fecal excretion of total radioactivity. However, when food restriction was combined with administration of sucrose polyester, there was a dramatic, eightfold average increase in excretion of fecal radioactivity. This synergistic effect was reversed (within 24 hr) when the animals were transferred to a normal diet. Measurement of total body radioactivity confirmed that food restriction plus sucrose polyester treatment reduced the body content of the pesticide. We conclude that stimulation of intestinal excretion may offer a new approach to treatment of patients exposed to lipophilic environmental contaminants

Biodegradable Nanoparticles Made of Amino-Acid-Based Ester Polymers: Preparation, Characterization, and In Vitro Biocompatibility Study

Directory of Open Access Journals (Sweden)

Temur Kantaria

2016-12-01

Full Text Available A systematic study of fabricating nanoparticles (NPs by cost-effective polymer deposition/solvent displacement (nanoprecipitation method has been carried out. Five amino acid based biodegradable (AABB ester polymers (four neutral and one cationic, four organic solvents miscible with water, and eight surfactants were tested for the fabrication of the goal NPs. Depending on the nature of the AABB polymers, organic solvents and surfactants, as well as on the fabrication conditions, the size (Mean Particle Diameter of the NPs could be tuned within 42 ÷ 398 nm, the zeta-potential within 12.5 ÷ +28 mV. The stability (resuspendability of the NPs upon storage (at room temperature and refrigerated was tested as well. In Vitro biocompatibility study of the NPs was performed with four different stable cell lines: A549, HeLa (human; RAW264.7, Hepa 1-6 (murine. Comparing the NPs parameters, their stability upon storage, and the data of biological examinations the best were found: As the AABB polymer, a poly(ester amide composed of l-leucine, 1,6-hexanediol and sebacic acid–8L6, as a solvent (organic phase—DMSO, and as a surfactant, Tween 20.

Comparative study of structural and thermal behavior of aromatic polyester;Estudo comparativo do comportamento termico e estrutral de poliesteres aromaticos

Energy Technology Data Exchange (ETDEWEB)

Santos, Diego K.M., E-mail: diego_keller_1984@yahoo.com.b; Guimaraes, Danilo H.; Medeiros, Marina O. de A.; Jose, Nadia M. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; Prado, Luis A.S. de A. [Technische Universitaet Hamburg (TUHH), Harburg (Germany). Inst. of Polymer and Composites

2009-07-01

Aromatic polyesters have been currently used for the production of PET bottles and polymer fibers. Currently, thermodynamic study is necessary for production of polymers with mechanical properties, thermal degradation and satisfactory. Many thermodynamic properties of polymer solutions, such as solubility, swelling, and balance of the properties Colligative can be expressed in terms of interaction parameter of polymer-solvent {chi}. The present work presents the objective synthesize, characterize and assess the degree of swelling of aromatic polyesters. The polyester formed from the reaction of glycerol and terephthalic acid/phthalic, using varying molar ratios to the glycerolterephthalic acid/phthalic acid (1,0-1,0, 1,0-1,5, 1,0 -- 2.0), by mixing with mechanical agitation and by use of tin catalyst. We studied the thermal and structural behavior through techniques: FTIR, TGA, DSC, XRD, SEM and swelling test. (author)

Microbial Enzymatic Degradation of Biodegradable Plastics.

Science.gov (United States)

Roohi; Bano, Kulsoom; Kuddus, Mohammed; Zaheer, Mohammed R; Zia, Qamar; Khan, Mohammed F; Ashraf, Ghulam Md; Gupta, Anamika; Aliev, Gjumrakch

2017-01-01

The renewable feedstock derived biodegradable plastics are important in various industries such as packaging, agricultural, paper coating, garbage bags and biomedical implants. The increasing water and waste pollution due to the available decomposition methods of plastic degradation have led to the emergence of biodegradable plastics and biological degradation with microbial (bacteria and fungi) extracellular enzymes. The microbes utilize biodegradable polymers as the substrate under starvation and in unavailability of microbial nutrients. Microbial enzymatic degradation is suitable from bioremediation point of view as no waste accumulation occurs. It is important to understand the microbial interaction and mechanism involved in the enzymatic degradation of biodegradable plastics under the influence of several environmental factors such as applied pH, thermo-stability, substrate molecular weight and/or complexity. To study the surface erosion of polymer film is another approach for hydrolytic degradation characteristion. The degradation of biopolymer is associated with the production of low molecular weight monomer and generation of carbon dioxide, methane and water molecule. This review reported the degradation study of various existing biodegradable plastics along with the potent degrading microbes (bacteria and fungi). Patents available on plastic biodegradation with biotechnological significance is also summarized in this paper. This paper assesses that new disposal technique should be adopted for the degradation of polymers and further research is required for the economical production of biodegradable plastics along with their enzymatic degradation. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Recovery and characterization of poly(3-Hydroxybutyric acid ...

African Journals Online (AJOL)

Darshan

Polyhydroxyalkanoates (PHA) are biodegradable polyesters accumulated intracellularly as energy resources by .... 20 min and filtered through Whatman No.1 filter paper and ... heating rate of 20°C air/min from ambient to a final temperature of.

Preparation of dual-layer coated polyester membranes with nuclear tracks and their wave-absorbing property

International Nuclear Information System (INIS)

Liu Cunxiong; Hu Lian; Ni Bangfa; Tian Weizhi; Fan Qiwen; Xiao Caijin; Nie Peng; Wang Pingsheng; Zhang Guiying; Huang Donghui

2010-01-01

Nanometer materials are of importance in developing electromagnetic-wave-absorbing materials. In this work, 16 μm thick polyester membranes were bombarded by 140 MeV 32 S ions from the HI-13 tandem accelerator to produce latent tracks. The bombarded samples were sensitized by DMF and UV light at 360 nm wavelength, before chemical etching by NaOH solution to develop latent tracks into pores in sizes of nanometers or micrometers in full depth of the membrane. The samples were coated with thin layers of barium ferrite and magnesium fluoride by vacuum evaporation. The reflectivity indices were measured at 2-18 GHz. The results indicate that the modified polyester membrane can effectively absorb 8-18 GHz radar waves.(authors)

Glass fibres reinforced polyester composites degradation monitoring by surface analysis

Energy Technology Data Exchange (ETDEWEB)

Croitoru, Catalin [“Transilvania” University of Brasov, Materials Engineering and Welding Department, Eroilor 29 Str., 500036 Brasov (Romania); Patachia, Silvia, E-mail: st.patachia@unitbv.ro [“Transilvania” University of Brasov, Product Design Environment and Mechatronics Department, Eroilor 29 Str., 500036 Brasov (Romania); Papancea, Adina [“Transilvania” University of Brasov, Product Design Environment and Mechatronics Department, Eroilor 29 Str., 500036 Brasov (Romania); Baltes, Liana; Tierean, Mircea [“Transilvania” University of Brasov, Materials Engineering and Welding Department, Eroilor 29 Str., 500036 Brasov (Romania)

2015-12-15

Highlights: • Glass fibre-reinforced polyester composites surface analysis by photographic method. • The composites are submitted to accelerated ageing by UV irradiation at 254 nm. • The UV irradiation promotes differences in the surface chemistry of the composites. • MB dye is differently adsorbed on surfaces with different degradation degrees. • Good correlation between the colouring degree and surface chemistry. - Abstract: The paper presents a novel method for quantification of the modifications that occur on the surface of different types of gel-coated glass fibre-reinforced polyester composites under artificial UV-ageing at 254 nm. The method implies the adsorption of an ionic dye, namely methylene blue, on the UV-aged composite, and computing the CIELab colour space parameters from the photographic image of the coloured composite's surface. The method significantly enhances the colour differences between the irradiated composites and the reference, in contrast with the non-coloured ones. The colour modifications that occur represent a good indicative of the surface degradation, alteration of surface hydrophily and roughness of the composite and are in good correlation with the ATR-FTIR spectroscopy and optical microscopy results. The proposed method is easier, faster and cheaper than the traditional ones.

Gliding arc surface treatment of glass-fiber-reinforced polyester enhanced by ultrasonic irradiation

DEFF Research Database (Denmark)

Kusano, Yukihiro; Norrman, Kion; Drews, Joanna Maria

2011-01-01

. The efficiency of such a plasma treatment at atmospheric pressure can be further improved by ultrasonic irradiation onto the surface during the treatment. In the present work glass fiber reinforced polyester (GFRP) plates are treated using an atmospheric pressure gliding arc with and without ultrasonic...

Biodegradable Implants in Orthopaedics and Traumatology

OpenAIRE

YETKIN, Haluk

2014-01-01

Biodegradable implants are an alternative to metallic implants and have the advantage of not being necessary to remove once the fracture has healed. Twenty-two patients with fractures were treated with biodegradable implants. There were osteolysis in eleven patients; however, no serious complication was encountered. Although biodegradable implants are expensive, a second surgical procedure to remove the implants is not necessary, relieving the patient of the related costs and risks.

Anaerobic biodegradation of hexazinone in four sediments

International Nuclear Information System (INIS)

Wang Huili; Xu Shuxia; Tan Chengxia; Wang Xuedong

2009-01-01

Anaerobic biodegradation of hexazinone was investigated in four sediments (L1, L2, Y1 and Y2). Results showed that the L2 sediment had the highest biodegradation potential among four sediments. However, the Y1 and Y2 sediments had no capacity to biodegrade hexazinone. Sediments with rich total organic carbon, long-term contamination history by hexazinone and neutral pH may have a high biodegradation potential because the former two factors can induce the growth of microorganisms responsible for biodegradation and the third factor can offer suitable conditions for biodegradation. The addition of sulfate or nitrate as electron acceptors enhanced hexazinone degradation. As expected, the addition of electron donors (lactate, acetate or pyruvate) substantially inhibited the degradation. In natural environmental conditions, the effect of intermediate A [3-(4-hydroxycyclohexyl)-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H, 3H)dione] on anaerobic hexazinone degradation was negligible because of its low level.

Biodegradable and compostable alternatives to conventional plastics

Science.gov (United States)

Song, J. H.; Murphy, R. J.; Narayan, R.; Davies, G. B. H.

2009-01-01

Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers. The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all ‘good’ or petrochemical-based products are all ‘bad’. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemical-based counterparts. Specific examples are given from new research on biodegradability in simulated ‘home’ composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted. PMID:19528060

Biodegradable and compostable alternatives to conventional plastics.

Science.gov (United States)

Song, J H; Murphy, R J; Narayan, R; Davies, G B H

2009-07-27

Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers. The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all 'good' or petrochemical-based products are all 'bad'. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemical-based counterparts. Specific examples are given from new research on biodegradability in simulated 'home' composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted.

Test procedures for polyester immobilized salt-containing surrogate mixed wastes

International Nuclear Information System (INIS)

Biyani, R.K.; Hendrickson, D.W.

1997-01-01

These test procedures are written to meet the procedural needs of the Test Plan for immobilization of salt containing surrogate mixed waste using polymer resins, HNF-SD-RE-TP-026 and to ensure adequacy of conduct and collection of samples and data. This testing will demonstrate the use of four different polyester vinyl ester resins in the solidification of surrogate liquid and dry wastes, similar to some mixed wastes generated by DOE operations

Polymeric blends from post-consumer PET and polyester becoming of glycerol and phthalic acid

International Nuclear Information System (INIS)

Miranda, C.S.; Brioude, M.; Fiuza, R.P.; Luporini, S.; Carvalho, R.F.; Jose, N.M.

2010-01-01

Preparation of physical mixture or polymer blends is a very important method to obtain a final product with excellent balance of properties, where one component can compensate for the poor property of another, and is often a modified low cost compared to development and synthesis of a new polymer. PET has become a major waste of post-consumer plastics and aiming to remedy this problem, this work aims to obtain blends from recycled PET and polyesters derived from glycerol and phthalic acid. The material with higher proportion of PET showed better thermal properties, observed by TGA and DSC, with a similar profile of pure PET. In XRD analysis showed a semicrystalline, while the SEM is a smooth surface on all materials, characteristic of pure polyester. The ratio of 50% its surface showed a probable immiscibility of polymers. (author)

Manufacturing of kevlar/polyester composite by resin transfer moulding using conventional and microwave heating

International Nuclear Information System (INIS)

Abdullah, I.

2015-01-01

Microwave heating was incorporated into the resin transfer moulding technique. Polytetrafluoroethylene (PTFE) mould was used to cure the composite panel. Through the use of microwave heating, the mechanical and physical properties of produced Kevlar fibre/polyester composites were compared to those manufactured by conventional resin transfer moulding. The flexural modulus and flexural strength of 6-ply conventionally cured composites was 45% and 9% higher than the flexural modulus and flexural strength of 6-ply microwaved cured composites, respectively. However, 19% increase in interlaminar shear strength (ILSS) and 2% increase in compressive strength was observed in 6-ply microwave cured composites. This enhancement in ILSS and compressive strength is attributed to the better interfacial bonding of polyester resin with Kevlar fibres in microwaved cured composite, which was also confirmed via electron microscopy scanning. Furthermore, the microwave cured composite yielded maximum void contents (3%). (author)

Effective Interfacially Polymerized Polyester Solvent Resistant Nanofiltration Membrane from Bioderived Materials

KAUST Repository

Abdellah, Mohamed H.

2018-05-18

Utilization of sustainable and environmentally friendly solvents for the preparation of membranes has attracted growing interest in recent years. In this work, a polyester thin film composite solvent resistant nanofiltration (SRNF) membrane is prepared by interfacial polymerization on a cellulose support. The cellulose support is prepared by nonsolvent‐induced phase separation from a dope solution containing an ionic liquid as an environmentally friendly solvent (negligible vapor pressure). The polyester film is formed via the interfacial reaction between quercetin, a plant‐derived polyphenol, and terephthaloyl chloride. Alpha‐pinene is used as a green alternative solvent to dissolve terephthaloyl chloride (TPC) while quercetin is dissolved in a 0.2 m NaOH solution. The interfacial polymerization reaction is successfully confirmed by Fourier transform infrared and X‐ray photoelectron spectroscopy while scanning electron and atomic force microscopy are used to characterize the membrane structure. The composite membrane shows an outstanding performance with a molecular weight cut‐off around 330 Da combined with a dimethylformamide (DMF) permeance up to 2.8 L m−2 bar−1 h−1. The membrane is stable in strong aprotic solvents such as DMF offering potential application in the pharmaceutical and petrochemical industries.

Karakterstik Serapan Suara Komposit Polyester Berpenguat Serat Tapis Kelapa

OpenAIRE

Astika, I Made; Dwijana, I Gusti Komang

2016-01-01

The purpose of this study is to investigate of sound absorption of coconut filter fiber composites. The research material made with coconut filter fiber as reinforcement and matrix resin unsaturated polyester (UPRs) type Yukalac BQTN 157 with 1% hardener types MEKPO (Methyl Ethyl Ketone Peroxide) and fiber treatment by  0,5% KMnO4. Production methods is poltrusion and the variations of fiber volume fraction are 20, 25 and 30% and fiber length are 5, 10 and 15 mm. Testing of sound absorpt...

Damage of polyesters by the atmospheric free radical oxidant NO3 •: a product study involving model systems

Science.gov (United States)

Goeschen, Catrin

2013-01-01

Summary Manufactured polymer materials are used in increasingly demanding applications, but their lifetime is strongly influenced by environmental conditions. In particular, weathering and ageing leads to dramatic changes in the properties of the polymers, which results in decreased service life and limited usage. Despite the heavy reliance of our society on polymers, the mechanism of their degradation upon exposure to environmental oxidants is barely understood. In this work, model systems of important structural motifs in commercial high-performing polyesters were used to study the reaction with the night-time free radical oxidant NO3 • in the absence and presence of other radical and non-radical oxidants. Identification of the products revealed ‘hot spots’ in polyesters that are particularly vulnerable to attack by NO3 • and insight into the mechanism of oxidative damage by this environmentally important radical. It is suggested that both intermediates as well as products of these reactions are potentially capable of promoting further degradation processes in polyesters under environmental conditions. PMID:24204400

Adhesion improvement of glass-fibre-reinforced polyester composites by gliding arc discharge treatment

DEFF Research Database (Denmark)

Kusano, Yukihiro; Sørensen, Bent F.; Løgstrup Andersen, Tom

2013-01-01

A gliding arc is a plasma that can be operated at atmospheric pressure and applied for plasma surface treatment for adhesion improvement. In the present work, glass-fibre-reinforced polyester plates were treated using an atmospheric pressure gliding arc discharge with an air flow to improve...

Effect OF NaOH Treatment on Bending Strength Of The Polyester Composite Reinforce By Sugar Palm Fibers

Science.gov (United States)

Arif Irfai, Mochamad; Wulandari, Diah; Sutriyono; Marsyahyo, Eko

2018-04-01

The objective of this research is to investigate the effect of NaOH treatment on bending strength of lamina composite reinforced by sugar palm fiber. To know of mechanism fracture can be done with visual inspection of the fracture surface. The Materials used are random sugar palm fibers that have been in the treatment of NaOH, polyester resin and hardener. Sugar palm fibers after washed and dried then soaked NaOH with a long time soaking 0, 2, 4, 6 and 8 hours. The bending test specimens were produced according to ASTM D 790. All specimens were post cured at 62°C for 4 hours. The Bending test was carried out on a universal testing machine. The SEM analysis has conducted to provide the analysis on interface adhesion between the surfaces of fiber with the matrix. The result shows that polyester composite reinforced by sugar palm fiber has highest bending stress 176.77 N/mm2 for 2 hours of a long time soaking NaOH, the highest flexural strain 0.27 mm for 2 hours of a long time soaking NaOH, elongation 24.05% for 2 hours of a long time soaking NaOH and the highest bending modulus 1.267 GPa for 2 hours of a long time soaking NaOH. Based on the results, it can be concluded that the polyester composite reinforced by sugar palm fiber has the optimum bending properties for a long time soaking 2 hours. The fracture surface shows that the polyester composite reinforced by sugar palm fiber pull out that indicate weakens the bond between fiber and matrix.

Multiwalled carbon nanotube coated polyester fabric as textile based flexible counter electrode for dye sensitized solar cell.

Science.gov (United States)

Arbab, Alvira Ayoub; Sun, Kyung Chul; Sahito, Iftikhar Ali; Qadir, Muhammad Bilal; Jeong, Sung Hoon

2015-05-21

Textile wearable electronics offers the combined advantages of both electronics and textile characteristics. The essential properties of these flexible electronics such as lightweight, stretchable, and wearable power sources are in strong demand. Here, we have developed a facile route to fabricate multi walled carbon nanotube (MWCNT) coated polyester fabric as a flexible counter electrode (CE) for dye sensitized solar cells (DSSCs). A variety of MWCNT and enzymes with different structures were used to generate individual enzyme-dispersed MWCNT (E-MWCNT) suspensions by non-covalent functionalization. A highly concentrated colloidal suspension of E-MWCNT was deposited on polyester fabric via a simple tape casting method using an air drying technique. In view of the E-MWCNT coating, the surface structure is represented by topologically randomly assembled tubular graphene units. This surface morphology has a high density of colloidal edge states and oxygen-containing surface groups which execute multiple catalytic sites for iodide reduction. A highly conductive E-MWCNT coated fabric electrode with a surface resistance of 15 Ω sq(-1) demonstrated 5.69% power conversion efficiency (PCE) when used as a flexible CE for DSSCs. High photo voltaic performance of our suggested system of E-MWCNT fabric-based DSSCs is associated with high sheet conductivity, low charge transfer resistance (RCT), and excellent electro catalytic activity (ECA). Such a conductive fabric demonstrated stable conductivity against bending cycles and strong mechanical adhesion of E-MWCNT on polyester fabric. Moreover, the polyester fabric is hydrophobic and, therefore, has good sealing capacity and retains the polymer gel electrolyte without seepage. This facile E-MWCNT fabric CE configuration provides a concrete fundamental background towards the development of textile-integrated solar cells.

Surface modification of polyester synthetic leather with tetramethylsilane by atmospheric pressure plasma

Energy Technology Data Exchange (ETDEWEB)

Kan, C.W., E-mail: tccwk@polyu.edu.hk [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Kwong, C.H. [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Ng, S.P. [Hong Kong Community College, The Hong Kong Polytechnic University (Hong Kong)

2015-08-15

Highlights: • Atmospheric pressure plasma treatment improved surface performance of polyester synthetic leather with tetramethylsilane. • XPS and FTIR confirmed the deposition of organosilanes on the sample's surface. • Contact angle increases to 138° after plasma treatment. - Abstract: Much works have been done on synthetic materials but scarcely on synthetic leather owing to its surface structures in terms of porosity and roughness. This paper examines the use of atmospheric pressure plasma (APP) treatment for improving the surface performance of polyester synthetic leather by use of a precursor, tetramethylsilane (TMS). Plasma deposition is regarded as an effective, simple and single-step method with low pollution. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) confirm the deposition of organosilanes on the sample's surface. The results showed that under a particular combination of treatment parameters, a hydrophobic surface was achieved on the APP treated sample with sessile drop static contact angle of 138°. The hydrophobic surface is stable without hydrophilic recovery 30 days after plasma treatment.

Compressive fatigue tests on a unidirectional glass/polyester composite at cryogenic temperatures

International Nuclear Information System (INIS)

Stone, E.L.; El-Marazki, L.O.; Young, W.C.

1979-01-01

The fatigue testing of a unidirectional glass-reinforced polyester composite at cryogenic temperatures to simulate the cyclic compressive loads of the magnet support struts in a superconductive magnetic energy storage unit is reported. Right circular cylindrical specimens were tested at 77, 4.2 K and room temperature at different stress levels using a 1-Hz haversine waveform imposed upon a constant baseload in a load-controlled closed-loop electrohydraulic test machine. Two failure modes, uniform mushrooming near one end and a 45 deg fracture line through the middle of the specimen, are observed, with no systematic difference in fatigue life between the modes. Fatigue lives obtained at 77 and 4.2 K are found to be similar, with fatigue failure at 100,000 cycles occurring at stress levels of 70 and 75% of the ultimate compressive strengths of specimens at room temperature and 77 K, respectively. The room temperature fatigue lives of the glass/polyester specimens are found to be intermediate between those reported for glass/epoxy composites with different glass contents costing over twice as much

Surface modification of polyester synthetic leather with tetramethylsilane by atmospheric pressure plasma

International Nuclear Information System (INIS)

Kan, C.W.; Kwong, C.H.; Ng, S.P.

2015-01-01

Highlights: • Atmospheric pressure plasma treatment improved surface performance of polyester synthetic leather with tetramethylsilane. • XPS and FTIR confirmed the deposition of organosilanes on the sample's surface. • Contact angle increases to 138° after plasma treatment. - Abstract: Much works have been done on synthetic materials but scarcely on synthetic leather owing to its surface structures in terms of porosity and roughness. This paper examines the use of atmospheric pressure plasma (APP) treatment for improving the surface performance of polyester synthetic leather by use of a precursor, tetramethylsilane (TMS). Plasma deposition is regarded as an effective, simple and single-step method with low pollution. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) confirm the deposition of organosilanes on the sample's surface. The results showed that under a particular combination of treatment parameters, a hydrophobic surface was achieved on the APP treated sample with sessile drop static contact angle of 138°. The hydrophobic surface is stable without hydrophilic recovery 30 days after plasma treatment

Fabrication of polyester microchannel with functional surface for electro-chromatography - Incorporation of detection devices into the microchip -

International Nuclear Information System (INIS)

Uchiyama, Katsumi; Qiu, Jing Miao; Hobo, Toshiyuki

2001-01-01

In recent years, new analytical techniques using microchip devise have been extensively studied (micro-TAS). One of the most successful examples is capillary electrophoresis (CE) with glass plate fabricated by photolithography followed by the chemical or physical etching process. Micro CE one of the most excellent separation techniques, performs separations in microchannel formed in appreciate substrate material. We developed a fabrication method for polyester micro channels with aikene alcohol inside the wall of the channel and demonstrated the usefulness of the polymer microchip. Although many researchers have been studying microchannel or micro-devices for analytical use, miniaturization of the total system including sample introduction, separation, detection and data treatment is still under development. Especially, the miniaturization of the detection system will be a hard bar to be overcome. Our method, based upon the in situ polymerization of polyester resin on an appreciate template, can be exported to let some parts incorporated directly into the microchip during the polymerization process. In this paper, we will describe the incorporation of detection components (light emitting diode and optical fiber) into polyester microchip and the application of the microchip to the analysis of amino acids separated by electrophoresis.

Comparison of post-operative wound infection after inguinal hernia repair with polypropylene mesh and polyester mesh

International Nuclear Information System (INIS)

Mughal, M.A.; Ahmed, M.; Sajid, M.T.; Mustafa, Q.U.A.; Shukr, I.; Ahsan, J.

2012-01-01

Objective: To compare post operative wound infection frequency after inguinal hernia repair with polypropylene and polyester mesh using standard Lichtenstein hernioplasty technique. Study Design: Randomized controlled trial. Place and Duration: This study was conducted at general surgery department CMH/MH Rawalpindi from 8th April 2007 to 1st Jan 2008 over a period of 09 months. Patients and Materials: Sixty patients received through outpatient department with diagnosis of inguinal hernia satisfying inclusion/exclusion criteria were included. Patients were divided into two groups randomly. Group 1 included those patients in whom polypropylene mesh was used while group II patients were implanted with polyester mesh. Demographic as well as data concerning post operative wound infection was collected and analyzed. Results: Fifty seven patients (95%) were males while remaining (05%) were females. Mean age in group I was 41.17+-9.99 years while in group II was 41.47+-9.79 years (p=0.907). One patient (3.3%) in each group developed wound infection diagnosed by clinical evidence of pain at wound site, redness, induration and purulent discharge. Conclusion: There is no difference in post operative wound infection rate after inguinal Lichtenstein hernioplasty using either polypropylene or polyester mesh. (author)

Nanocomposites Based on Biodegradable Polymers

Directory of Open Access Journals (Sweden)

Ilaria Armentano

2018-05-01

Full Text Available In the present review paper, our main results on nanocomposites based on biodegradable polymers (on a time scale from 2010 to 2018 are reported. We mainly focused our attention on commercial biodegradable polymers, which we mixed with different nanofillers and/or additives with the final aim of developing new materials with tunable specific properties. A wide list of nanofillers have been considered according to their shape, properties, and functionalization routes, and the results have been discussed looking at their roles on the basis of different adopted processing routes (solvent-based or melt-mixing processes. Two main application fields of nanocomposite based on biodegradable polymers have been considered: the specific interaction with stem cells in the regenerative medicine applications or as antimicrobial materials and the active role of selected nanofillers in food packaging applications have been critically revised, with the main aim of providing an overview of the authors’ contribution to the state of the art in the field of biodegradable polymeric nanocomposites.

Biodegradation of oils in uranium deposits

International Nuclear Information System (INIS)

Landais, P.

1989-01-01

The biodegradation of free hydrocarbons that have migrated in reservoir facies has often been observed in the field of petroleum exploration. This alteration is characterized by the progressive removal by bacteria of the different types of hydrocarbons: n-alkanes, branched alkanes, aromatics, cycloalkanes, etc. One of the most important consequences of biodegradation is the biogenic reduction of sulphate, which has been noticed in several Pb-Zn deposits. Biodegradation of oils spatially associated with uranium mineralizations has been observed in Temple Mountain, Utah, and the Grand Canyon, Arizona, in the United States of America, and in Lodeve in France. It leads to the transformation of fluid oils into solid bitumens. Emphasis is placed on the relationships between the effects of biodegradation on organic matter (oxidation of aromatization) and the nature of aqueous fluids analysed in fluid inclusions trapped in authigenic minerals. Different mechanisms are proposed to explain the transformations of organic matter during biodegradation and their possible links with the ore forming process. (author). 40 refs, 13 figs, 1 tab

Preparation of Acetylated Guar Gum – Unsaturated Polyester Composites & Effect of Water on Their Properties

Directory of Open Access Journals (Sweden)

David D’Melo

2012-07-01

Full Text Available Guar gum has seen extensive use in blends, however, its application as a filler in thermoset composites has as yet not been investigated. The effect of the addition of guar gum and its acetyl derivatives on the kinetics of water diffusion in unsaturated polyester composites was studied. The effect of water on the mechanical properties of the composites was studied with respect to the nature of filler, filler concentration and time of immersion. All the mechanical properties were observed to decrease on exposure to water. Further, it was observed that acetylated guar gum, with a degree of substitution of 0.21, showed the best mechanical properties, surpassing the other filled composites and that of the pure unsaturated polyester. Thus, acetylated guar gum showed promise as eco-friendly filler in composite formulation.

Here today, gone tomorrow: biodegradable soft robots

Science.gov (United States)

Rossiter, Jonathan; Winfield, Jonathan; Ieropoulos, Ioannis

2016-04-01

One of the greatest challenges to modern technologies is what to do with them when they go irreparably wrong or come to the end of their productive lives. The convention, since the development of modern civilisation, is to discard a broken item and then procure a new one. In the 20th century enlightened environmentalists campaigned for recycling and reuse (R and R). R and R has continued to be an important part of new technology development, but there is still a huge problem of non-recyclable materials being dumped into landfill and being discarded in the environment. The challenge is even greater for robotics, a field which will impact on all aspects of our lives, where discards include motors, rigid elements and toxic power supplies and batteries. One novel solution is the biodegradable robot, an active physical machine that is composed of biodegradable materials and which degrades to nothing when released into the environment. In this paper we examine the potential and realities of biodegradable robotics, consider novel solutions to core components such as sensors, actuators and energy scavenging, and give examples of biodegradable robotics fabricated from everyday, and not so common, biodegradable electroactive materials. The realisation of truly biodegradable robots also brings entirely new deployment, exploration and bio-remediation capabilities: why track and recover a few large non-biodegradable robots when you could speculatively release millions of biodegradable robots instead? We will consider some of these exciting developments and explore the future of this new field.

Observation of hairpin defects in a nematic main-chain polyester

Science.gov (United States)

Li, M. H.; Brûlet, A.; Davidson, P.; Keller, P.; Cotton, J. P.

1993-04-01

The conformation of a main-chain liquid crystalline polyester in its oriented nematic phase has been determined by small-angle neutron scattering. The data are fitted by a model of rigid cylinder with orientational fluctuations. For a low degree of polymerization (~9) the chain is almost completely elongated in the direction of the nematic field. For a polymer 3 times longer, the existence of two hairpins is shown at high temperature; this number decreases with decreasing temperature.

Biodegradation of Volatile Organic Compounds and Their Effects on Biodegradability under Co-Existing Conditions.

Science.gov (United States)

Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

2017-09-27

Volatile organic compounds (VOCs) are major pollutants that are found in contaminated sites, particularly in developed countries such as Japan. Various microorganisms that degrade individual VOCs have been reported, and genomic information related to their phylogenetic classification and VOC-degrading enzymes is available. However, the biodegradation of multiple VOCs remains a challenging issue. Practical sites, such as chemical factories, research facilities, and illegal dumping sites, are often contaminated with multiple VOCs. In order to investigate the potential of biodegrading multiple VOCs, we initially reviewed the biodegradation of individual VOCs. VOCs include chlorinated ethenes (tetrachloroethene, trichloroethene, dichloroethene, and vinyl chloride), BTEX (benzene, toluene, ethylbenzene, and xylene), and chlorinated methanes (carbon tetrachloride, chloroform, and dichloromethane). We also summarized essential information on the biodegradation of each kind of VOC under aerobic and anaerobic conditions, together with the microorganisms that are involved in VOC-degrading pathways. Interactions among multiple VOCs were then discussed based on concrete examples. Under conditions in which multiple VOCs co-exist, the biodegradation of a VOC may be constrained, enhanced, and/or unaffected by other compounds. Co-metabolism may enhance the degradation of other VOCs. In contrast, constraints are imposed by the toxicity of co-existing VOCs and their by-products, catabolite repression, or competition between VOC-degrading enzymes. This review provides fundamental, but systematic information for designing strategies for the bioremediation of multiple VOCs, as well as information on the role of key microorganisms that degrade VOCs.

Biodegradation of Volatile Organic Compounds and Their Effects on Biodegradability under Co-Existing Conditions

Science.gov (United States)

Yoshikawa, Miho; Zhang, Ming; Toyota, Koki

2017-01-01

Volatile organic compounds (VOCs) are major pollutants that are found in contaminated sites, particularly in developed countries such as Japan. Various microorganisms that degrade individual VOCs have been reported, and genomic information related to their phylogenetic classification and VOC-degrading enzymes is available. However, the biodegradation of multiple VOCs remains a challenging issue. Practical sites, such as chemical factories, research facilities, and illegal dumping sites, are often contaminated with multiple VOCs. In order to investigate the potential of biodegrading multiple VOCs, we initially reviewed the biodegradation of individual VOCs. VOCs include chlorinated ethenes (tetrachloroethene, trichloroethene, dichloroethene, and vinyl chloride), BTEX (benzene, toluene, ethylbenzene, and xylene), and chlorinated methanes (carbon tetrachloride, chloroform, and dichloromethane). We also summarized essential information on the biodegradation of each kind of VOC under aerobic and anaerobic conditions, together with the microorganisms that are involved in VOC-degrading pathways. Interactions among multiple VOCs were then discussed based on concrete examples. Under conditions in which multiple VOCs co-exist, the biodegradation of a VOC may be constrained, enhanced, and/or unaffected by other compounds. Co-metabolism may enhance the degradation of other VOCs. In contrast, constraints are imposed by the toxicity of co-existing VOCs and their by-products, catabolite repression, or competition between VOC-degrading enzymes. This review provides fundamental, but systematic information for designing strategies for the bioremediation of multiple VOCs, as well as information on the role of key microorganisms that degrade VOCs. PMID:28904262

BTEX biodegradation by bacteria from effluents of petroleum refinery.

Science.gov (United States)

Mazzeo, Dânia Elisa Christofoletti; Levy, Carlos Emílio; de Angelis, Dejanira de Franceschi; Marin-Morales, Maria Aparecida

2010-09-15

Groundwater contamination with benzene, toluene, ethylbenzene and xylene (BTEX) has been increasing, thus requiring an urgent development of methodologies that are able to remove or minimize the damages these compounds can cause to the environment. The biodegradation process using microorganisms has been regarded as an efficient technology to treat places contaminated with hydrocarbons, since they are able to biotransform and/or biodegrade target pollutants. To prove the efficiency of this process, besides chemical analysis, the use of biological assessments has been indicated. This work identified and selected BTEX-biodegrading microorganisms present in effluents from petroleum refinery, and evaluated the efficiency of microorganism biodegradation process for reducing genotoxic and mutagenic BTEX damage through two test-systems: Allium cepa and hepatoma tissue culture (HTC) cells. Five different non-biodegraded BTEX concentrations were evaluated in relation to biodegraded concentrations. The biodegradation process was performed in a BOD Trak Apparatus (HACH) for 20 days, using microorganisms pre-selected through enrichment. Although the biodegradation usually occurs by a consortium of different microorganisms, the consortium in this study was composed exclusively of five bacteria species and the bacteria Pseudomonas putida was held responsible for the BTEX biodegradation. The chemical analyses showed that BTEX was reduced in the biodegraded concentrations. The results obtained with genotoxicity assays, carried out with both A. cepa and HTC cells, showed that the biodegradation process was able to decrease the genotoxic damages of BTEX. By mutagenic tests, we observed a decrease in damage only to the A. cepa organism. Although no decrease in mutagenicity was observed for HTC cells, no increase of this effect after the biodegradation process was observed either. The application of pre-selected bacteria in biodegradation processes can represent a reliable and

Advances in Biodegradation of Multiple Volatile Organic Compounds

Science.gov (United States)

Zhang, M.; Yoshikawa, M.

2017-12-01

Bioremediation of soil and groundwater containing multiple contaminants remains a challenge in environmental science and engineering because complete biodegradation of all components is necessary but very difficult to accomplish in practice. This presentation provides a brief overview on advances in biodegradation of multiple volatile organic compounds (VOCs) including chlorinated ethylenes, benzene, toluene and dichloromethane (DCM). Case studies on aerobic biodegradation of benzene, toluene and DCM, and integrated anaerobic-aerobic biodegradation of 7 contaminants, specifically, tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), vinyl chloride (VC), DCM, benzene and toluene will be provided. Recent findings based on systematic laboratory experiments indicated that aerobic toluene degradation can be enhanced by co-existence of benzene. Propioniferax, not a known benzene, toluene and DCM degrader can be a key microorganism that involves in biodegradation when the three contaminants co-exist. Integrated anaerobic-aerobic biodegradation is capable of completely degrading the seven VOCs with initial concentrations less than 30 mg/L. Dehalococcoides sp., generally considered sensitive to oxygen, can survive aerobic conditions for at least 28 days, and can be activated during the subsequent anaerobic biodegradation. This presentation may provide a systematic information about biodegradation of multiple VOCs, and a scientific basis for the complete bioremediation of multiple contaminants in situ.

Thermal and mechanical behaviour of sub micron sized fly ash reinforced polyester resin composite

Science.gov (United States)

Nantha Kumar, P.; Rajadurai, A.; Muthuramalingam, T.

2018-04-01

The utilization of particles reinforced resin matrix composites is being increased owing to its lower density and high strength to weight ratio. In the present study, an attempt has been made to synthesize fly ash particles reinforced polyester resin composite for engine cowling application. The thermal stability and mechanical behaviours such as hardness and flexural strength of the composite with 2, 3 and 4 weight % of reinforcement is studied and analyzed. The thermo gravimetric analysis indicates that the higher addition of reinforcement increases the decomposition temperature due to its refractory nature. It is also observed that the hardness increases with higher filler addition owing to the resistance of FA particles towards penetration. The flexural strength is found to increase up to the addition of 3% of FA particles, whereas the polyester resin composite prepared with 4% FA particles addition is observed to have low flexural strength owing to agglomeration of particles.

Biodegradable poly lactone-family polymer and their applications in medical field

International Nuclear Information System (INIS)

Wang, S.; Bei, J.

2005-01-01

Poly lactone-family polymers such as poly lactide, poly glycolide and polycaprolactone are kind aliphatic polyester. Since they can degrade by hydrolysis reaction under all the ph condition and possess biocompatibility, biodegradability and other good properties, especially they included not peptide bond in their molecules, they are non-antigen and non-immunization, as well as have no-toxicity and no-stimulation. So they are interested biomaterials and very useful in medical field. However the properties of all of the homo-poly lactones can not be changed in a large range, the limited properties result in limited applications of these homo-poly lactones. Based on macromolecular design, a series of copolylactones such as poly(lactide-co-glycolide) (PLGA), poly(glycolide-co-lactide-co-caprolactone) tri- component copolymer (PGLC), tri- and multi-block poly lactide/poly(ethylene oxide) copolymer (TPLE and BPLE), as well as polycaprolactone/poly lactide/poly(ethylene oxide) copolymer (PCEL) et al were synthesized by copolymerization among various lactone monomers or lactone monomers with poly(ethylene glycol). These copolylactones have wide range of degradation life from several months to years and different mechanical properties. After plasma treatment the surface property of the copolylactones were improved further and cell affinity of the copolylactones was improved obviously. The applications of these poly lactone-family polymers in medical field for used as drug carrier in drug delivery system, and as cell scaffold in tissue engineering were discussed

Editorial: Biodegradable Materials

Directory of Open Access Journals (Sweden)

Carl Schaschke

2014-11-01

Full Text Available This Special Issue “Biodegradable Materials” features research and review papers concerning recent advances on the development, synthesis, testing and characterisation of biomaterials. These biomaterials, derived from natural and renewable sources, offer a potential alternative to existing non-biodegradable materials with application to the food and biomedical industries amongst many others. In this Special Issue, the work is expanded to include the combined use of fillers that can enhance the properties of biomaterials prepared as films. The future application of these biomaterials could have an impact not only at the economic level, but also for the improvement of the environment.

XPS utilization in the characterization of glycerol based polyesters; Utilizacao de XPS na caracterizacao de poliesteres a base de glicerol

Energy Technology Data Exchange (ETDEWEB)

Brioude, M.M.; Miranda, C.S.; Pereira, R.; Ohara, L.; Bargiela, P.; Rocha, M.G.M.C.; Jose, N.M., E-mail: mgcr@ufba.b [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Escola Politecnica. Inst. de Quimica

2010-07-01

X-ray photoelectron spectroscopy-XPS allows the determination of all elements of the periodical table, except hydrogen and helium, and is a very used technique for the polymers characterization, its spectra constitutes a 'fingerprint' of the material. Two samples of polymers were prepared from glycerol and fumaric acid and glycerol and terephthalic acid, with a molar ratio of 1:1 and 1:1.5. The general spectra show the presence of carbon and oxygen, the main components of the polymer. From the binding energies values of the C1s and O1s high resolution spectra it was possible to determine the carbon functional groups. Their concentration were determined and the presence of the aromatic carbon in the terephthalic polyesters was observed, and also similar proportions of aliphatic carbon and ester groups in the fumaric acid polyesters. For both polyesters, an amount of carboxyl group appears, indicating the terminal non-reacted groups. These results were confirmed qualitatively by FTIR. (author)

Structural, optical and electrical characteristics of ITO thin films deposited by sputtering on different polyester substrates

International Nuclear Information System (INIS)

Guillen, C.; Herrero, J.

2008-01-01

Indium tin oxide (ITO) thin films were deposited by sputtering at room temperature on glass and different polyester substrates; namely polyarylate (PA), polycarbonate (PC) and polyethylene terephtalate (PET). The influence of the substrate on the structural, optical and electrical characteristics of the ITO layers was investigated. The sputtered films exhibited crystallization in the (2 2 2) orientation, with higher mean crystallite size and lower structural distortion onto PET than onto PA, PC or glass substrates. ITO films deposited onto PET showed also higher band gap energy, higher carrier concentration and lower resistivity than the ITO layers onto the other tested substrates. These optical and electrical characteristics have been related to the structural distortion that was found dependent on the specific polyester substrate

Hydrocarbons biodegradation in unsaturated porous medium; Biodegradation des hydrocarbures en milieu poreux insature

Energy Technology Data Exchange (ETDEWEB)

Gautier, C

2007-12-15

Biological processes are expected to play an important role in the degradation of petroleum hydrocarbons in contaminated soils. However, factors influencing the kinetics of biodegradation are still not well known, especially in the unsaturated zone. To address these biodegradation questions in the unsaturated zone an innovative experimental set up based on a physical column model was developed. This experimental set up appeared to be an excellent tool for elaboration of a structured porous medium, with well defined porous network and adjusted water/oil saturations. Homogeneous repartition of both liquid phases (i.e., aqueous and non aqueous) in the soil pores, which also contain air, was achieved using ceramic membranes placed at the bottom of the soil column. Reproducible interfaces (and connectivity) are developed between gas, and both non mobile water and NAPL phases, depending on the above-defined characteristics of the porous media and on the partial saturations of these three phases (NAPL, water and gas). A respirometric apparatus was coupled to the column. Such experimental set up have been validated with hexadecane in dilution in an HMN phase. This approach allowed detailed information concerning n-hexadecane biodegradation, in aerobic condition, through the profile of the oxygen consumption rate. We have taken benefit of this technique, varying experimental conditions, to determine the main parameters influencing the biodegradation kinetics and compositional evolution of hydrocarbons, under steady state unsaturated conditions and with respect to aerobic metabolism. Impacts of the nitrogen quantity and of three different grain sizes have been examined. Biodegradation of petroleum cut, as diesel cut and middle distillate without aromatic fraction, were, also studied. (author)

MECHANICAL AND THERMAL PROPERTIES OF COMPOSITES FROM UNSATURATED POLYESTER FILLED WITH OIL PALM ASH

Directory of Open Access Journals (Sweden)

M.S. Ibrahim

2012-06-01

Full Text Available Oil palm ash (OPA is available in abundance, is renewable, can be obtained at no cost and shows good performance at high thermal conditions. Combinations of the unsaturated polyester with natural fillers have been reported to improve the mechanical and thermal properties of composites. Utilisation of oil palm ash as a filler in the manufacture of polymer composites can significantly reduce the requirement for other binders or matrixes of composite materials. This research uses oil palm ash as a filler to form composites through the investigation of the effect of different contents of filler on the properties of OPA-filled unsaturated polyester (UP/OPA composites. The effect of different volume fractions, i.e., 0, 10, 20 and 30 vol.% of oil palm ash introduced into 100, 90, 80 and 70 vol.% of an unsaturated polyester matrix on the composite mechanical properties, i.e., tensile and flexural, has been studied, together with thermal gravimetric analysis (TGA and differential scanning calorimetric (DSC. Specimens were prepared using compression moulding techniques based on the ASTM D790 and D5083 standards for flexural and tensile tests, respectively. The tensile and flexural mechanical properties of UP/OPA composites were improved in modulus by increasing the filler content. Thermal stability of the composites increased as the OPA filler content was increased, which was a logical consequence because of the high thermal stability of the silica compound of the OPA filler compared with that of the UP matrix. The results from the surface electron microscope (SEM analysis were the extension of mechanical and thermal tests.

Effect of gamma irradiation on poly(butylene naphthalate) based polyesters

International Nuclear Information System (INIS)

Malavasi, I.; Consolati, G.; Quasso, F.; Soccio, M.; Gigli, M.; Negrin, M.; Macerata, E.; Giacobbo, F.; Lotti, N.; Munari, A.; Mariani, M.

2016-01-01

The present work investigates the effect of gamma radiation on the properties of three naphthalate-based polyesters, i.e. poly(butylene naphthalate) (PBN), poly(diethylene naphthalate) (PDEN) and poly(thiodiethylene naphthalate) (PTDEN). In addition, the analogous terephthalate-based polymers of PDEN and PTDEN, i.e. poly(diethylene terephthalate) (PDET) and poly(thiodiethylene terephthalate) (PTDET), are also investigated, in order to check the effect of a lower number of aromatic rings. All the polymers, irradiated in air at different absorbed doses, were characterized by several techniques. The data obtained indicate that all the polymers, except PBN, show a decrease of molecular weight with the dose increase. The thermal behavior and the morphology confirm the previous results and show that the higher the crystallinity degree and number of aromatic rings, the higher the radiation resistance. The introduction of heteroatoms decreases the ability of a polymer to crystallize due to a reduction of polymer chain symmetry, thus worsening their radiation resistance. - Highlights: • Gamma irradiation of polyesters with different number of aromatic rings was studied. • Effect of gamma radiation on PBN, PDEN, PTDEN, PDET, and PTDET was investigated. • Irradiated polymers were studied by GPC, DSC and PALS. • Introduction of heteroatoms decreases polymers radiation resistance. • Presence of double aromatic ring confers a higher stability with increasing doses.

Analise térmica e microscópica de laminados biodegradáveis obtidos a partir de farinha de mandioca, sorbitol e poli (butileno adipato co-tereftalato PBAT. Thermal and microscopic analysis of biodegradable laminates made from cassava flour, sorbitol and poly (butylene adipate-co-terephthalate PBAT - doi: 10.4025/actascitechnol.v35i4.13183

Directory of Open Access Journals (Sweden)

Henrique Tirolli Rett

2013-10-01

Full Text Available O objetivo deste trabalho foi desenvolver blendas de materiais laminados biodegradáveis, utilizando farinha de mandioca como fonte de amido, fibras naturais, sorbitol como plastificante e PBAT. Primeiro obteve-se peletes de três formulações diferentes e a partir destes, utilizou-se a termoprensagem a alta temperatura como alternativa na formação dos laminados. A caracterização foi feita através de microscopia eletrônica de varredura (MEV e calorimetria diferencia de varredura (CDV. A quantidade se sorbitol que melhor se ajustou à extrusão foi a de 15% (peso/peso; a formulação do laminado mais homogêneo, observada pela microscopia, foi de 55:40:15 (farinha/sorbitol/PBAT. As fibras ficaram dispersas por toda a superfície nos três tratamentos estudados, porém, por dentre eles, observaram-se zonas dispersas das fibras. Conforme se aumentou o teor de farinha, houve aumento no ponto de fusão dos laminados em comparação ao PBAT puro.Blends of biodegradable laminated materials were developed using cassava flour as starch and natural fibers source, sorbitol as a plasticizer and PBAT as a biodegradable polyester. After obtaining pellets from three different formulations, high temperature thermopressure was used to form laminates. The characterization was performed by scanning electron microscopy (SEM and by differential scanning calorimetry (DSC. The amount of sorbitol for the best extrusion process was 15% (weight/weight and the formulation of the best homogeneity observed by microscopy was 55:40:15 (flour/sorbitol/PBAT. Although fibers were dispersed throughout the surface in the three treatments, scattered areas of fibers could be found among them. As rates of flour increased, an increase in the melting point of the laminates occurred when compared to pure PBAT.  

78 FR 17637 - Polyester Staple Fiber From Taiwan: Preliminary Results of Antidumping Duty Administrative Review...

Science.gov (United States)

2013-03-22

... DEPARTMENT OF COMMERCE International Trade Administration [A-583-833] Polyester Staple Fiber From... Administration, International Trade Administration, Department of Commerce. SUMMARY: The Department of Commerce.../CVD Operations, Office 1, Import Administration, International Trade Administration, U.S. Department...

Poly(Neopentyl Glycol Furanoate): A Member of the Furan-Based Polyester Family with Smart Barrier Performances for Sustainable Food Packaging Applications

OpenAIRE

Laura Genovese; Nadia Lotti; Valentina Siracusa; Andrea Munari

2017-01-01

In the last decade, there has been an increased interest from the food packaging industry toward the development and application of bioplastics, to contribute to the sustainable economy and to reduce the huge environmental problem afflicting the planet. In the present work, we focus on a new furan-based polyester, poly(neopentyl glycol 2,5-furanoate) (PNF) to be used for sustainable food packaging applications. The aromatic polyester was successfully synthesized with high molecular weight, th...

Synthesis and characterization of sulfonated polyesters derived from glycerol; Sintese e caracterizacao de poliesteres sulfonados obtidos a partir do glicerol

Energy Technology Data Exchange (ETDEWEB)

Fiuza, R.A.; Jose, N.M.; Boaventura, J.S. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica; Fiuza, R.P. [Universidade Federal da Bahia (EP/UFBA), Salvador, BA (Brazil). Escola Politecnica. Curso de Mestrado em Engenharia Quimica

2010-07-01

In this work were synthesized polyesters from glycerol and acid sulfonated phthalic previously. The materials were characterized by DSC, TGA, FTIR, SEM, XRD and XRF. The results showed effective sulfonation of phthalic acid. The presence of sulfonic groups promoted strong changes in the crystallinity of the new material makes the lens. The polyesters made from phthalic acid sulfonated combine characteristics such as heat resistance and groups that drivers potentiate the electrolyte for application in fuel cells proton exchange membrane and also for gas separation. (author)

Therapeutic nanoparticles from novel multiblock engineered polyesterurethanes

Energy Technology Data Exchange (ETDEWEB)

Mattu, C., E-mail: clara.mattu@polito.it; Boffito, M.; Sartori, S. [Dipartimento di Ingegneria Meccanica e Aerospaziale, Politecnico di Torino (Italy); Ranzato, E. [Universita del Piemonte Orientale, DiSIT-Dipartimento di Scienze e Innovazione Tecnologica (Italy); Bernardi, E.; Sassi, M. P. [INRIM-Istituto Nazionale di Ricerca Metrologica (Italy); Di Rienzo, A. M.; Ciardelli, G. [Dipartimento di Ingegneria Meccanica e Aerospaziale, Politecnico di Torino (Italy)

2012-12-15

A novel biodegradable material belonging to the class of polyester-urethanes (PURs), based on poly({epsilon}-caprolactone) (PCL) blocks, was proposed as matrix-forming material for the preparation of nanoparticles by the solvent displacement method. This method has been widely applied to prepare nanoparticles with reproducible, small size with commercially available polyesters or polyester-polyether copolymers. These carriers often displayed fast and poorly controllable release rates. In response to these problems we proposed the insertion of polyesters into a more complex microstructure, such as that of polyurethanes, characterized by the alternation of hard and soft segments, in order to modulate and control the degradation rate and release profiles. PCL-based PUR (C-BC2000) was synthesized according to a two step synthesis procedure. Commercial PCL and poly(d, l lactide) (PLA) were used as controls; and paclitaxel, a potent anti-neoplastic drug, was encapsulated inside all carriers. Carriers prepared with the new material showed no intrinsic cytotoxicity (A-431 cells), with similar size in the range 211-226 nm and surface charge as the commercial controls. Moreover, C-BC2000 nanoparticles exhibited a slightly faster degradation rate, a much higher encapsulation efficiency (89 % against 24 % and 18 % for PLA and PCL, respectively) and a longer and more controlled release profile. This study highlighted the possibility to successfully employ biodegradable polyurethanes to prepare particles for controlled drug delivery, suggesting further and extensive investigation on the introduction of different PUR formulations in this field.

The application of FT-IR spectrum method in photocuring process for polyester acrylate

International Nuclear Information System (INIS)

Cao Jin; Lu Xianliang; Zhang Zhenli

1995-01-01

This paper describes that the UV curing process of polyester acrylate can be monitored by measuring the degree of double bonds conversion with FT-IR spectroscopy. The various factors effect the UV curing rate. The relation between the curing rate and the concentration of photoinitiator, crosslinking agent, UV light intensity was discussed. (author)

Anaerobic biodegradability and treatment of Egyption domestic sewage

NARCIS (Netherlands)

Elmitwally, T.A.; Al-Sarawey, A.; El-Sherbiny, M.F.; Zeeman, G.; Lettinga, G.

2003-01-01

The anaerobic biodegradability of domestic sewage for four Egyptian villages and four Egyptian cities was determined in batch experiments. The results showed that the biodegradability of the Egyptian-villages sewage (73%) was higher than that of the cities (66%). The higher biodegradability of the

Biodegradable Metals From Concept to Applications

CERN Document Server

Hermawan, Hendra

2012-01-01

This book in the emerging research field of biomaterials covers biodegradable metals for biomedical applications. The book contains two main parts where each of them consists of three chapters. The first part introduces the readers to the field of metallic biomaterials, exposes the state of the art of biodegradable metals, and reveals its application for cardiovascular implants. It includes some fundamental aspects to give basic understanding on metals for further review on the degradable ones is covered in chapter one. The second chapter introduces the concept of biodegradable metals, it's st

Biodegradation of acetanilide herbicides acetochlor and butachlor in soil.

Science.gov (United States)

Ye, Chang-ming; Wang, Xing-jun; Zheng, He-hui

2002-10-01

The biodegradation of two acetanilide herbicides, acetochlor and butachlor in soil after other environmental organic matter addition were measured during 35 days laboratory incubations. The herbicides were applied to soil alone, soil-SDBS (sodium dodecylbenzene sulfonate) mixtures and soil-HA (humic acid) mixtures. Herbicide biodegradation kinetics were compared in the different treatment. Biodegradation products of herbicides in soil alone samples were identified by GC/MS at the end of incubation. Addition of SDBS and HA to soil decreased acetochlor biodegradation, but increased butachlor biodegradation. The biodegradation half-life of acetochlor and butachlor in soil alone, soil-SDBS mixtures and soil-HA mixtures were 4.6 d, 6.1 d and 5.4 d and 5.3 d, 4.9 d and 5.3 d respectively. The biodegradation products were hydroxyacetochlor and 2-methyl-6-ethylaniline for acetochlor, and hydroxybutachlor and 2,6-diethylaniline for butachlor.

Influence of gamma radiation on thermal properties and water vapor transmission of poly(3-hydroxybutyrate) (PHB) in blends

Energy Technology Data Exchange (ETDEWEB)

Forster, Pedro L.; Martins, Natalia A.; Parra, Duclerc F.; Egute, Nayara S.; Lugao, Ademar B., E-mail: dfparra@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2009-07-01

Biodegradable polymers are a newly emerging field. A vast number of biodegradable polymers have been synthesized recently and some microorganisms and enzymes capable of degrading them have been identified. Polyesters such as poly(3-hydroxybutyrate) (PHB) or other polyhydroxyalkanoates (PHAs) have attracted commercial and academic interest as new biodegradable materials. In this work, we investigated the effect of gamma radiation on the thermal properties and biodegradation behavior of PHB in blend with poly(ethyleneglycol)(PEG). The samples were irradiated at gamma radiation of 5 and 10 kGy. The thermal behaviour was investigated by utilization of differential scanning calorimetry (DSC) changes in thermal stability, glass transition and melting point were reported. (author)

Influence of gamma radiation on thermal properties and water vapor transmission of poly(3-hydroxybutyrate) (PHB) in blends

International Nuclear Information System (INIS)

Forster, Pedro L.; Martins, Natalia A.; Parra, Duclerc F.; Egute, Nayara S.; Lugao, Ademar B.

2009-01-01

Biodegradable polymers are a newly emerging field. A vast number of biodegradable polymers have been synthesized recently and some microorganisms and enzymes capable of degrading them have been identified. Polyesters such as poly(3-hydroxybutyrate) (PHB) or other polyhydroxyalkanoates (PHAs) have attracted commercial and academic interest as new biodegradable materials. In this work, we investigated the effect of gamma radiation on the thermal properties and biodegradation behavior of PHB in blend with poly(ethyleneglycol)(PEG). The samples were irradiated at gamma radiation of 5 and 10 kGy. The thermal behaviour was investigated by utilization of differential scanning calorimetry (DSC) changes in thermal stability, glass transition and melting point were reported. (author)

Ultrasound enhanced 50 Hz plasma treatment of glass-fiber-reinforced polyester at atmospheric pressure

DEFF Research Database (Denmark)

Kusano, Yukihiro; Norrman, Kion; Singh, Shailendra Vikram

2013-01-01

Glass-fiber-reinforced polyester (GFRP) plates are treated using a 50Hz dielectric barrier discharge at a peak-to-peak voltage of 30 kV in helium at atmospheric pressure with and without ultrasonic irradiation to study adhesion improvement. The ultrasonic waves at the fundamental frequency...

The use of sterilised polyester mosquito net mesh for inguinal hernia repair in Ghana

NARCIS (Netherlands)

Clarke, M. G.; Oppong, C.; Simmermacher, R.; Park, K.; Kurzer, M.; Vanotoo, L.; Kingsnorth, A. N.

The use of alloplastic mesh is now commonplace in hernia repair. However, in developing countries, cheaper alternatives to commercial mesh are required due to the high associated cost. Whilst nylon mosquito net mesh has been trialled previously, this study aimed to assess the use of polyester

Mechanical and Physical Properties of Polyester Polymer Concrete Using Recycled Aggregates from Concrete Sleepers

Directory of Open Access Journals (Sweden)

Francisco Carrión

2014-01-01

Full Text Available Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate, and waste aggregates (basalt and limestone coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%, and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior.

Mechanical and physical properties of polyester polymer concrete using recycled aggregates from concrete sleepers.

Science.gov (United States)

Carrión, Francisco; Montalbán, Laura; Real, Julia I; Real, Teresa

2014-01-01

Currently, reuse of solid waste from disused infrastructures is an important environmental issue to study. In this research, polymer concrete was developed by mixing orthophthalic unsaturated polyester resin, artificial microfillers (calcium carbonate), and waste aggregates (basalt and limestone) coming from the recycling process of concrete sleepers. The variation of the mechanical and physical properties of the polymer concrete (compressive strength, flexural strength, modulus of elasticity, density, and water absorption) was analyzed based on the modification of different variables: nature of the recycled aggregates, resin contents (11 wt%, 12 wt%, and 13 wt%), and particle-size distributions of microfillers used. The results show the influence of these variables on mechanical performance of polymer concrete. Compressive and flexural strength of recycled polymer concrete were improved by increasing amount of polyester resin and by optimizing the particle-size distribution of the microfillers. Besides, the results show the feasibility of developing a polymer concrete with excellent mechanical behavior.

Performance of Plain Woven Jute Fabric-Reinforced Polyester Matrix Composite in Multilayered Ballistic System

Directory of Open Access Journals (Sweden)

Sergio Neves Monteiro

2018-02-01

Full Text Available The ballistic performance of plain woven jute fabric-reinforced polyester matrix composites was investigated as the second layer in a multilayered armor system (MAS. Volume fractions of jute fabric, up to 30 vol %, were mixed with orthophthalic polyester to fabricate laminate composites. Ballistic tests were conducted using high velocity 7.62 mm ammunition. The depth of penetration caused by the bullet in a block of clay witness, simulating a human body, was used to evaluate the MAS ballistic performance according to the international standard. The fractured materials after tests were analyzed by scanning electron microscopy (SEM. The results indicated that jute fabric composites present a performance similar to that of the much stronger Kevlar™, which is an aramid fabric laminate, as MAS second layer with the same thickness. The mechanism of this similar ballistic behavior as well as the comparative advantages of the jute fabric composites over the Kevlar™ are discussed.

Complications of transvaginal silicone-coated polyester synthetic mesh sling.

Science.gov (United States)

Govier, F E; Kobashi, K C; Kuznetsov, D D; Comiter, C; Jones, P; Dakil, S E; James, R

2005-10-01

To report a premarket multicenter trial to test the feasibility of a transvaginal silicone-coated polyester synthetic mesh sling in women with anatomic incontinence. Fifty-one patients in four centers underwent transvaginal placement of a silicone-coated polyester synthetic mesh sling (American Medical Systems) during an 8-month period. Of the 51 patients, 31 were part of a prospective institutional review board-approved feasibility trial in three centers funded by American Medical Systems (group 1) and 20 underwent implantation by a single surgeon and their data were retrospectively reviewed (group 2). The studies were done concomitantly, and all slings were fixed transvaginally with bone anchors. All patients in group 1 were followed up at 4 weeks, 6 months, and 1 year (as applicable) with repeat questionnaires, physical examinations, and pad tests. In group 1, 20 patients completed 6 months of follow-up. Ten patients (32%) required a second surgical procedure at an average of 183 days (range 68 to 343) postoperatively. Eight patients (26%) had vaginal extrusion of the mesh, one (3%) required sling lysis, and one (3%) required sling removal because of infection. In group 2, 8 patients (40%) underwent sling removal for vaginal extrusion at a mean of 160 days (range 83 to 214). Transvaginally placed silicone-coated mesh slings used for the treatment of urinary incontinence demonstrated an unacceptably high vaginal extrusion rate in this study. Once identified, this study was immediately terminated, and this product was not marketed for this application in the United States.

Implantable microencapsulated dopamine (DA): prolonged functional release of DA in denervated striatal tissue.

Science.gov (United States)

McRae, A; Hjorth, S; Mason, D; Dillon, L; Tice, T

1990-01-01

Biodegradable controlled-release microcapsule systems made with the biocompatible biodegradable polyester excipient poly [DL-lactide-co-gly-colide] constitute an exciting new technology for drug delivery to the central nervous system (CNS). The present study describes functional observations indicating that implantation of dopamine (DA) microcapsules encapsulated within two different polymer excipients into denervated striatal tissue assures a prolonged release of the transmitter in vivo. This technology has a considerable potential for basic and possibly clinical research.

[A novel method based on Y-shaped cotton-polyester thread microfluidic channel].

Science.gov (United States)

Wang, Lu; Shi, Yan-ru; Yan, Hong-tao

2014-08-01

A novel method based on Y-shaped microfluidic channel was firstly proposed in this study. The microfluidic channel was made of two cotton-polyester threads based on the capillary effect of cotton-polyester threads for the determination solutions. A special device was developed to fix the Y-shaped microfluidic channel by ourselves, through which the length and the tilt angle of the channel can be adjusted as requested. The spectrophotometry was compared with Scan-Adobe Photoshop software processing method. The former had a lower detection limit while the latter showed advantages in both convenience and fast operations and lower amount of samples. The proposed method was applied to the determination of nitrite. The linear ranges and detection limits are 1.0-70 micromol x L(-1), 0.66 micromol x L(-1) (spectrophotometry) and 50-450 micromol x L(-1), 45.10 micromol x L(-1) (Scan-Adobe Photoshop software processing method) respectively. This method has been successfully used to the determination of nitrite in soil samples and moat water with recoveries between 96.7% and 104%. It was proved that the proposed method was a low-cost, rapid and convenient analytical method with extensive application prospect.

Physicomechanical evaluation of polypropylene, polyester, and polytetrafluoroethylene meshes for inguinal hernia repair.

Science.gov (United States)

Deeken, Corey R; Abdo, Michael S; Frisella, Margaret M; Matthews, Brent D

2011-01-01

For meshes to be used effectively for hernia repair, it is imperative that engineers and surgeons standardize the terminology and techniques related to physicomechanical evaluation of these materials. The objectives of this study were to propose standard techniques, perform physicomechanical testing, and classify materials commonly used for inguinal hernia repair. Nine meshes were evaluated: 4 polypropylene, 1 polyester, 1 polytetrafluoroethylene, and 3 partially absorbable. Physical properties were determined through image analysis, laser micrometry, and density measurements. Biomechanical properties were determined through suture retention, tear resistance, uniaxial, and ball burst testing with specimens tested in 2 different orientations. A 1-way ANOVA with Tukey's post-test or a t-test were performed, with p INFINIT (WL Gore & Associates) did not resist tearing as effectively as the others. All meshes exhibited supraphysiologic burst strengths except INFINIT and ULTRAPRO. Significant differences exist between the physicomechanical properties of polypropylene, polyester, polytetrafluoroethylene, and partially absorbable mesh prostheses commonly used for inguinal hernia repair. Orientation of the mesh was also shown to be critical for the success of meshes, particularly those demonstrating anisotropy. Copyright © 2011 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Biodegradable lubricants - ''the solution for future?''

International Nuclear Information System (INIS)

Jahan, A.

1997-01-01

The environmental impact of lubricants use concern the direct effects from spills but also the indirect effects such as their lifetime and the emissions from thermal engines. The biodegradable performances and the toxicity are the environmental criteria that must be taken into account in the development and application of lubricants together with their technical performances. This paper recalls first the definition of biodegradable properties of hydrocarbons and the standardized tests, in particular the CEC and AFNOR tests. Then, the biodegradable performances of basic oils (mineral, vegetal, synthetic esters, synthetic hydrocarbons etc..), finite lubricants (hydraulic fluids..) and engine oils is analyzed according to these tests. Finally, the definition of future standards would take into account all the environmental characteristics of the lubricant: biodegradable performances, energy balance (CO 2 , NOx and Hx emissions and fuel savings), eco-toxicity and technical performances (wearing and cleanliness). (J.S.)

Biodegradation behaviors of cellulose nanocrystals -PVA nanocomposites

Directory of Open Access Journals (Sweden)

Mahdi Rohani

2014-11-01

Full Text Available In this research, biodegradation behaviors of cellulose nanocrystals-poly vinyl alcohol nanocomposites were investigated. Nanocomposite films with different filler loading levels (3, 6, 9 and 12% by wt were developed by solvent casting method. The effect of cellulose nanocrystals on the biodegradation behaviors of nanocomposite films was studied. Water absorption and water solubility tests were performed by immersing specimens into distilled water. The characteristic parameter of diffusion coefficient and maximum moisture content were determined from the obtained water absorption curves. The water absorption behavior of the nanocomposites was found to follow a Fickian behavior. The maximum water absorption and diffusion coefficients were decreased by increasing the cellulose nanocrystals contents, however the water solubility decrease. The biodegradability of the films was investigated by immersing specimens into cellulase enzymatic solution as well as by burial in soil. The results showed that adding cellulose nanocrystals increase the weight loss of specimens in enzymatic solution but decrease it in soil media. The limited biodegradability of specimens in soil media attributed to development of strong interactions with solid substrates that inhibit the accessibility of functional groups. Specimens with the low degree of hydrolysis underwent extensive biodegradation in both enzymatic and soil media, whilst specimens with the high degree of hydrolysis showed recalcitrance to biodegradation under those conditions.

Blendas PHB/copoliésteres biodegradáveis : biodegradação em solo Biodegradable PHB/copolyester blends : biodegradation in soil

Directory of Open Access Journals (Sweden)

Suzan A. Casarin

2013-01-01

Full Text Available Este trabalho apresenta os resultados do comportamento de blendas do polímero biodegradável PHB poli(hidroxibutirato com os copoliésteres também biodegradáveis EastarBio® e Ecoflex®, na composição de 75% de PHB e 25% dos copoliésteres, em contato com solo composto simulado. Foi também avaliada a influência da adição de pó de serra ou farinha de madeira, na proporção de 70% da blenda e 30% de pó de serra (p.d.s.. A biodegradação foi avaliada para amostras após 30, 60 e 90 dias em contato com solo, através de análises gravimétricas, morfológicas e mecânicas. A preparação inicial dos grânulos dos compostos poliméricos foi feita por extrusão, utilizando uma extrusora dupla-rosca e a moldagem dos corpos de prova foi realizada através da moldagem por injeção. Os materiais estudados biodegradam nas condições testadas. A blenda PHB/EastarBio® (75/25 + 30% p.d.s. apresentou maior redução de massa, 29% após 90 dias. Notou-se que a biodegradação se inicia pela superfície do material e que 90 dias são insuficientes para observar alterações internas.This paper reports on blends made with the biodegradable polymers poly(hydroxybutyrate (PHB and Eastar Bio® or Ecoflex® copolyesters, in contact with simulated compound soil. The blends had 75% of PHB and 25% of copolyesters. We also analyzed the influence from adding 30% of powder-wood or wood flour (WPC to 70% of the blend. Biodegradation was analyzed for samples after 30, 60 and 90 days in contact with soil, through thermogravimetric, morphological and mechanical analyses. The initial preparation of the granules of polymeric compounds was made by extrusion, using a twin-screw extruder and the molding of the specimens was performed by injection molding. The analysis indicated material biodegradation under the conditions tested. The PHB/Eastar Bio® blend (75/25 + 30% WPC exhibited the highest degradation with 29% of mass loss at the end of 90 days. Biodegradation

Critical evaluation of biodegradable polymers used in nanodrugs

Science.gov (United States)

Marin, Edgar; Briceño, Maria Isabel; Caballero-George, Catherina

2013-01-01

Use of biodegradable polymers for biomedical applications has increased in recent decades due to their biocompatibility, biodegradability, flexibility, and minimal side effects. Applications of these materials include creation of skin, blood vessels, cartilage scaffolds, and nanosystems for drug delivery. These biodegradable polymeric nanoparticles enhance properties such as bioavailability and stability, and provide controlled release of bioactive compounds. This review evaluates the classification, synthesis, degradation mechanisms, and biological applications of the biodegradable polymers currently being studied as drug delivery carriers. In addition, the use of nanosystems to solve current drug delivery problems are reviewed. PMID:23990720

In silico design of PHA synthase and its validation by PHAs producing bacterial isolates

Directory of Open Access Journals (Sweden)

Susrita Sahoo

2017-10-01

Full Text Available Biopolymers are important alternatives to the petroleum-based plastics due to environment friendly manufacturing processes, biodegradability and biocompatibility. Therefore use of novel biopolymers such as polylactide, polysaccharides, aliphatic polyesters and polyhydroxyalkonoates (PHAs is of interest. PHAs are biodegradable polyesters of hydroxyalkanoates (HA produced from renewable resources by using microorganisms as intracellular carbon and energy storage compounds.  Even though PHAs are promising candidate for biodegradable polymers, however, the production cost limits their application on an industrial scale. Therefore an attempt was made to model different PHAs synthases which are the key enzyme in the biosynthesis of Polyhydroxyalkanoates as the structural information of this enzyme is in dark veil.Then molecular docking  of class I  PHA  Synthase from Ralstonia Eutrophia was done to study the PHA synthase activity. As there are lots of strain which needs to explore for the production of PHA. This investigation leads to find out the most industrial applicable microbes. Few bacterial isolates from soil sample were screened for production of PHA followed by the validation of the enzymatic activity and its product characterization to understand its structural properties.

Kekuatan Lentur Komposit Polyester Berpenguat Serat Tapis Kelapa

Directory of Open Access Journals (Sweden)

I Made Astika

2015-07-01

Full Text Available Penelitian ini bertujuan untuk menyelidiki sifat mekanis yaitu kekuatan lentur dari kompositpolyester yang diperkuat dengan serat tapis kelapa. Di masa depan komposit ini dapatdigunakan untuk menggantikan kayu, bambu dan gipsun yang harganya mahal dan tidaktahan air. Komposit dibuat dengan memanfaatkan serat sabut kelapa dan matriks resinUnsaturated-Polyester (UPRs jenis Yucalac 157 BQTN, campuran 1% hardener jenis MEKPO(Methyl Ethyl Ketone Peroxide dan perendaman serat dalam larutan alkali KMnO4 0,5%.Metode produksi yang digunakan adalah press hand lay up dengan orientasi serat acak.Desain komposit dengan variasi fraksi volume serat 20, 25 dan 30% dan variasi panjang serat5, 10 dan 15 mm. Hasil penelitian menunjukkan bahwa semakin besar fraksi volume danpanjang serat dalam komposit maka kekuatan lentur semakin tinggi. Mode patahan yangteramati adalah patah getas, debonding, pullout dan crack deflection.Kata kunci: komposit, serat tapis kelapa, kekuatan lentur, mode patahan The purpose of this study is to investigate the mechanical properties i.e. flexural strength ofcomposites coconut filter fiber. In the future this material can be used to replace the wood,bamboo and gipsun which are high price and lower water resistance.The research material made with coconut filter fiber as reinforcement and matrix resinunsaturated polyester (UPRs type Yukalac BQTN 157, with 1% hardener types MEKPO(Methyl Ethyl Ketone Peroxide and fiber treatment by 0.5% KMnO4. Production methods arepress hand lay-up and the variations of fiber volume fraction are 20, 25 and 30% and fiberlength are 5, 10 and 15 mm. Testing of mechanical properties is flexural test (ASTM - D790The results of research show that the longer of fiber and the bigger of fiber volume fraction,the higher of flexural strength are obtained. The fracture mode are overload, debonding ,pullout and crack deflectionKeywords : composites, coconut filter fiber, flexural strength, fracture mode

Biodegradation studies of diesel-contaminated soils and sediments

International Nuclear Information System (INIS)

Schlauch, M.; Clark, D.

1992-01-01

Radian Corporation is currently remediating the Atchison, Topeka and Sante Fe Railway Superfund site in Clovis, New Mexico. Biodegradation of the petroleum hydrocarbon-contaminated soils and sediments was chosen as the remedial alternative. In order to evaluate the optimum conditions for full-scale bioremediation at this site, Radian designed and implemented various laboratory and field studies. The initial laboratory treatability study was conducted to determine if hydrocarbons in both soils and sediments could be biodegraded using indigenous microorganisms, and determine that the soil were biodegradable, while the sediments were not due to inhibitory factors. To further evaluate the biodegradability6 of the sediments, a laboratory study was initiated which introduced chloride-resistant microbes. The study showed that the sediment bioremediation was possibly by utilizing these microbes; however, the cost was not favorable. Finally, a field plot study was initiated to determine how soil biodegradation would proceed in field conditions, to optimize influencing factors such as moisture and nutrient levels and bioseed addition, and to investigate alternate methods of bioremediating the sediments. Results showed that hydrocarbons in the soils biodegraded much faster in the field than in the lab, and that hydrocarbons in sediments applied to biotreated soils containing acclimated microorganisms were successfully biodegraded

Hydrodynamic parameters of linear aromatic polyester of 3-phenylglutaric acid and bisphenol A

Czech Academy of Sciences Publication Activity Database

Netopilík, Miloš; Kratochvíl, Jaroslav; Schallausky, F.; Reichelt, S.; Lederer, A.

2007-01-01

Roč. 12, č. 4 (2007), s. 285-300 ISSN 1023-666X R&D Projects: GA ČR GA203/07/0659; GA AV ČR IAA400500703 Institutional research plan: CEZ:AV0Z40500505 Keywords : chain parameters * linear polyester * size exclusion chromatography Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.386, year: 2007

Experimental studies of biodegradation of asphalt by microorganisms

International Nuclear Information System (INIS)

Mine, Tatsuya; Mihara, Morihiro; Ooi, Takao; Lin, Kong-hua; Kawakami, Yasushi

2000-04-01

On the geological disposal system of the radioactive wastes, the activities of the microorganisms that could degrade the asphalt might be significant for the assessment of the system performance. As the main effects of the biodegradation of the asphalt, the fluctuation of leaching behavior of the nuclides included in asphalt waste has been indicated. In this study, the asphalt biodegradation test was carried out. The microorganism of which asphalt degradation ability was comparatively higher under aerobic condition and anaerobic condition was used. The asphalt biodegradation rate was calculated and it was evaluated whether the asphalt biodegradation in this system could occur. The results show that the asphalt biodegradation rate under anaerobic and high alkali condition will be 300 times lower than under aerobic and neutral pH. (author)

Technology change priorities influencing competition quality promotion: Case study of Iran Keaton Polyester Manufacturing Company

Directory of Open Access Journals (Sweden)

Pouria Nour

2012-10-01

Full Text Available In the changing world with various customers’ demands the businesses tend to improve their advantages to beat their rivals by means of better quality, lower prices and so. For Iranian polyester market quality is of crucial importance and is achieved through changing and updating technologies. According to highly regarded model of CAPTECH, which is recommended by UNIDO, technology parameters are defined in each phase and not generally as a whole. In the end the biggest gaps are defined. The main goal is to prioritize the main parameters affecting Iranian polyester company's quality. In order to fulfill our goal, 20 high and medium managers were questioned for this paper. The questions were gathered according to UNIDO samples. After a qualitative and quantitative test we concluded that the biggest gap is for supply chain(56.91 and the lowest gap is for combination phase(43.97.

Green Polymer Precursors from Biomass-Based Levulinic Acid

NARCIS (Netherlands)

Chalid, M.; Heeres, H.J.; Broekhuis, A.A.

2012-01-01

Levulinic acid (LA) has been identified as a suitable chemical feedstock that can be isolated from biomass. Its conversion into γ-valerolactone (GVL) via hydrogenation and ringclosure to the lactone has been studied as a versatile route to the manufacture of biodegradable polyesters. For

Biosynthesis of poly-(R)-3-hydroxyalkanoate: an emulsion polymerization

NARCIS (Netherlands)

Koning, de G.J.M.; Maxwell, I.A.

1993-01-01

A review with 29 refs. Poly-(R)-3-hydroxyalkanoates (PHAs) are bacterial storage polyesters, which are accumulated by a wide variety of microorganisms as a reserve of carbon and energy. These biopolymers have received much attention because of their potential application as biodegradable and

Mass transfer analysis for terephthalic acid biodegradation by ...

African Journals Online (AJOL)

Biodegradation of terephthalic acid (TA) by polyvinyl alcohol (PVA)-alginate immobilized Pseudomonas sp. was carried out in a packed-bed reactor. The effect of inlet TA concentration on biodegradation was investigated at 30°C, pH 7 and flow rate of 20 ml/min. The effects of flow rate on mass transfer and biodegradation ...

Biodegradation of clofibric acid and identification of its metabolites

International Nuclear Information System (INIS)

Salgado, R.; Oehmen, A.; Carvalho, G.; Noronha, J.P.; Reis, M.A.M.

2012-01-01

Graphical abstract: Metabolites produced during clofibric acid biodegradation. Highlights: ► Clofibric acid is biodegradable. ► Mainly heterotrophic bacteria degraded the clofibric acid. ► Metabolites of clofibric acid biodegradation were identified. ► The metabolic pathway of clofibric acid biodegradation is proposed. - Abstract: Clofibric acid (CLF) is the pharmaceutically active metabolite of lipid regulators clofibrate, etofibrate and etofyllinclofibrate, and it is considered both environmentally persistent and refractory. This work studied the biotransformation of CLF in aerobic sequencing batch reactors (SBRs) with mixed microbial cultures, monitoring the efficiency of biotransformation of CLF and the production of metabolites. The maximum removal achieved was 51% biodegradation (initial CLF concentration = 2 mg L −1 ), where adsorption and abiotic removal mechanisms were shown to be negligible, showing that CLF is indeed biodegradable. Tests showed that the observed CLF biodegradation was mainly carried out by heterotrophic bacteria. Three main metabolites were identified, including α-hydroxyisobutyric acid, lactic acid and 4-chlorophenol. The latter is known to exhibit higher toxicity than the parent compound, but it did not accumulate in the SBRs. α-Hydroxyisobutyric acid and lactic acid accumulated for a period, where nitrite accumulation may have been responsible for inhibiting their degradation. A metabolic pathway for the biodegradation of CLF is proposed in this study.

High diffraction efficiency polarization gratings recorded by biphotonic holography in an azobenzene liquid crystalline polyester

DEFF Research Database (Denmark)

Sánchez, C; Alcalá, R; Hvilsted, Søren

2001-01-01

High diffraction efficiencies have been achieved with polarization gratings recorded in thin films of an azobenzene side-chain liquid crystalline polyester by means of biphotonic processes. Efficiency values up to 30% have been reached after an induction period of 300 s and subsequent evolution...

Atmospheric pressure H20 plasma treatment of polyester cord threads

International Nuclear Information System (INIS)

Simor, M.; Krump, H.; Hudec, I.; Rahel, J.; Brablec, A.; Cernak, M.

2004-01-01

Polyester cord threads, which are used as a reinforcing materials of rubber blend, have been treated in atmospheric-pressure H 2 0 plasma in order to enhance their adhesion to rubber. The atmospheric-pressure H 2 0 plasma was generated in an underwater diaphragm discharge. The plasma treatment resulted in approximately 100% improvement in the adhesion. Scanning electron microscopy investigation indicates that not only introduced surface polar groups but also increased surface area of the fibres due to a fibre surface roughening are responsible for the improved adhesive strength (Authors)

Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

Science.gov (United States)

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

2013-01-01

Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

Degradation of oxo-biodegradable plastic by Pleurotus ostreatus.

Directory of Open Access Journals (Sweden)

José Maria Rodrigues da Luz

Full Text Available Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate.

Degradation of Oxo-Biodegradable Plastic by Pleurotus ostreatus

Science.gov (United States)

da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Nunes, Mateus Dias; da Silva, Marliane de Cássia Soares; Kasuya, Maria Catarina Megumi

2013-01-01

Growing concerns regarding the impact of the accumulation of plastic waste over several decades on the environmental have led to the development of biodegradable plastic. These plastics can be degraded by microorganisms and absorbed by the environment and are therefore gaining public support as a possible alternative to petroleum-derived plastics. Among the developed biodegradable plastics, oxo-biodegradable polymers have been used to produce plastic bags. Exposure of this waste plastic to ultraviolet light (UV) or heat can lead to breakage of the polymer chains in the plastic, and the resulting compounds are easily degraded by microorganisms. However, few studies have characterized the microbial degradation of oxo-biodegradable plastics. In this study, we tested the capability of Pleurotus ostreatus to degrade oxo-biodegradable (D2W) plastic without prior physical treatment, such as exposure to UV or thermal heating. After 45 d of incubation in substrate-containing plastic bags, the oxo-biodegradable plastic, which is commonly used in supermarkets, developed cracks and small holes in the plastic surface as a result of the formation of hydroxyl groups and carbon-oxygen bonds. These alterations may be due to laccase activity. Furthermore, we observed the degradation of the dye found in these bags as well as mushroom formation. Thus, P. ostreatus degrades oxo-biodegradable plastics and produces mushrooms using this plastic as substrate. PMID:23967057

Biodegradability of polyurethane/polysaccharide blends

International Nuclear Information System (INIS)

Mothe, Cheila G.; Leite, Selma G.

2001-01-01

Biodegradable polymers for use in environmental waste-management has been the subject of much discussion over the last few years. Polyurethane mixtures with polysaccharide (80/20 and 90/10 w/w ) have been prepared and films obtained. These films were inoculated, according to ASTM G22-76 rule and analysed by thermogravimetry and scanning electronic microscopy (SEM). The results are discussed in terms of thermal degradation and biodegradability. (author)

Mechanical properties of composites based on unsaturated polyester resins obtained by chemical recycling of poly(ethylene terephthalate

Directory of Open Access Journals (Sweden)

Marinković Aleksandar D.

2013-01-01

Full Text Available Composites based on unsaturated polyester (UPe resins and fumed silica AEROSIL® RY 50, NY 50, RX 50 and NAX 50, as well as graphite, TiO2 or organically modified clay CLOISITE 30B were prepared in order to investigate the influence of reinforcing agents on the mechanical properties of composites. Unsaturated polyester resins were synthesized from maleic anhydride and products of glycolysis, obtained by depolymerization of poly(ethylene terephthalate with dipropylene glycol (UPe1 resin and triethylene glycol (UPe2 resin in the presence of tetrabutyl titanate catalyst. The obtained unsaturated polyesters were characterized by FTIR spectroscopy, acid and hydroxyl values, and their mechanical properties were also examined. Significant increase of the tensile modulus, tensile strength and decrease of the elongation at break was observed for composites prepared after addition of 10 wt.% of graphite or 10 wt.% of TiO2 to the UPe resins, indicating strong interaction between matrix and filler particles. On the other hand, nanocomposites prepared using UPe2 and hydrophobically modified silica nanoparticles showed lower tensile strength and tensile modulus than polymer matrix. The presence of CLOISITE 30B had no significant influence on the mechanical properties of UPe1, while tensile strength and tensile modulus of UPe2 increased after adding 10 wt.% of clay. [Projekat Ministarstva nauke Republike Srbije, br. 172013

California State Implementation Plan; San Diego County Air Pollution Control District; VOC Emissions from Polyester Resin Operations

Science.gov (United States)

EPA is taking final action to approve revisions to the San Diego County Air Pollution Control District (SDCAPCD) portion of the California SIP concerning volatile organic compound (VOC) emissions from polyester resin operations.

Poly(1,4-cyclohexanedimethylene 2,6-naphthalate polyester with high melting point: Effect of different synthesis methods on molecular weight and properties

Directory of Open Access Journals (Sweden)

N. Kasmi

2018-03-01

Full Text Available In the current manuscript, a new approach for the synthesis of poly(1,4- cyclohexanedimethylene 2,6-naphthalate (PCHDMN derived from dimethyl 2,6-naphthalenedicarboxylate (2,6-DMN and 1,4-Cyclohexanedimethanol (CHDM via melt polycondensation method is introduced. The effect of three different synthesis pathways, polycondensation time and temperature on polyesters molecular weight increase has been investigated. All of the prepared samples were characterized measuring their intrinsic viscosity (IV, thermal properties and morphology with differential scanning calorimetry (DSC and wide-angle X-ray diffraction (WAXD, respectively. The results demonstrated the effectiveness of the synthesis pathway proposed for the preparation of PCHDMN, resulting in high molecular weight (IV value around 0.5 dL/g and much shorter reaction time. Melt polycondensation temperatures above melting point of polyester should be avoided to be used due to the decomposition of polyester. This was proved by thermogravimetric analysis (TGA and Pyrolysis-gas chromatography–mass spectroscopy analysis (Py-GC/MS.

Drilling analysis of coir–fibre-reinforced polyester composites

Indian Academy of Sciences (India)

Administrator

... in a large variety of products, ranging from clothes to roofing of houses. Today, these fibre composites are appraised as eco- friendly materials owing to their biodegradability and ... method and the artificial neural network techniques. The.

Biodegradation of clofibric acid and identification of its metabolites

Energy Technology Data Exchange (ETDEWEB)

Salgado, R. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); ESTS-IPS, Escola Superior de Tecnologia de Setubal do Instituto Politecnico de Setubal, Rua Vale de Chaves, Campus do IPS, Estefanilha, 2910-761 Setubal (Portugal); Oehmen, A. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Carvalho, G. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Instituto de Biologia Experimental e Tecnologica (IBET), Av. da Republica (EAN), 2784-505 Oeiras (Portugal); Noronha, J.P. [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Reis, M.A.M., E-mail: amr@fct.unl.pt [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

2012-11-30

Graphical abstract: Metabolites produced during clofibric acid biodegradation. Highlights: Black-Right-Pointing-Pointer Clofibric acid is biodegradable. Black-Right-Pointing-Pointer Mainly heterotrophic bacteria degraded the clofibric acid. Black-Right-Pointing-Pointer Metabolites of clofibric acid biodegradation were identified. Black-Right-Pointing-Pointer The metabolic pathway of clofibric acid biodegradation is proposed. - Abstract: Clofibric acid (CLF) is the pharmaceutically active metabolite of lipid regulators clofibrate, etofibrate and etofyllinclofibrate, and it is considered both environmentally persistent and refractory. This work studied the biotransformation of CLF in aerobic sequencing batch reactors (SBRs) with mixed microbial cultures, monitoring the efficiency of biotransformation of CLF and the production of metabolites. The maximum removal achieved was 51% biodegradation (initial CLF concentration = 2 mg L{sup -1}), where adsorption and abiotic removal mechanisms were shown to be negligible, showing that CLF is indeed biodegradable. Tests showed that the observed CLF biodegradation was mainly carried out by heterotrophic bacteria. Three main metabolites were identified, including {alpha}-hydroxyisobutyric acid, lactic acid and 4-chlorophenol. The latter is known to exhibit higher toxicity than the parent compound, but it did not accumulate in the SBRs. {alpha}-Hydroxyisobutyric acid and lactic acid accumulated for a period, where nitrite accumulation may have been responsible for inhibiting their degradation. A metabolic pathway for the biodegradation of CLF is proposed in this study.

Liquid-crystalline polyesters with end nitroxyl radical and their use in living free-radical polymerization

Czech Academy of Sciences Publication Activity Database

Razina, A B.; Sedláková, Zdeňka; Bouchal, Karel; Tenkovtsev, A. V.; Ilavský, Michal

2002-01-01

Roč. 44, č. 9 (2002), s. 924-930 ISSN 0965-545X R&D Projects: GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : liquid crystal * polyesters * nitroxyl radical Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.627, year: 2002

Exploring the Substrate Scope of Baeyer–Villiger Monooxygenases with Branched Lactones as Entry towards Polyesters

NARCIS (Netherlands)

Delgove, Marie; Fürst, Maximilian; Fraaije, Marco; Bernaerts, Katrien; de Wildeman, Stefaan

2018-01-01

Baeyer–Villiger monooxygenases (BVMOs) are biocatalysts that are able to convert cyclic ketones into lactones by the insertion of oxygen. The aim of this study was to explore the substrate scope of several BVMOs with (biobased) cyclic ketones as precursors for the synthesis of branched polyesters.

Exploring the substrate scope of Baeyer-Villiger monooxygenases with branched lactones as entry towards polyesters

NARCIS (Netherlands)

Delgove, Marie; Fürst, Maximilian; Fraaije, Marco; Bernaerts, Katrien; De Wildeman, Stefaan M A

2018-01-01

Baeyer-Villiger monooxygenases (BVMOs) are biocatalysts able to convert cyclic ketones to lactones by the insertion of oxygen. The aim of this study was to explore the substrate scope of several BVMOs with (biobased) cyclic ketones as precursors for the synthesis of branched polyesters.The product

Biodegradable shape-memory block co-polymers for fast self-expandable stents.

Science.gov (United States)

Xue, Liang; Dai, Shiyao; Li, Zhi

2010-11-01

Block co-polymers PCTBVs (M(n) of 36,300-65,300 g/mol, T(m) of 39-40 and 142 degrees C) containing hyperbranched three-arm poly(epsilon-caprolactone) (PCL) as switching segment and microbial polyester PHBV as crystallizable hard segment were designed as biodegradable shape-memory polymer (SMP) for fast self-expandable stent and synthesized in 96% yield by the reaction of three-arm PCL-triol (M(n) of 4200 g/mol, T(m) of 47 degrees C) with methylene diphenyl 4,4'-diisocyanate isocynate (MDI) to form the hyperbrached MDI-linked PCL (PTCM; M(n) of 25,400 g/mol and a T(m) of 38 degrees C), followed by further polymerization with PHBV-diol (M(n) of 2200 g/mol, T(m) of 137 and 148 degrees C). The polymers were characterized by (1)H NMR, GPC, DSC, tensile test, and cyclic thermomechanical tensile test. PCTBVs showed desired thermal properties, mechanical properties, and ductile nature. PCTBV containing 25 wt% PHBV (PCTBV-25) demonstrated excellent shape-memory property at 40 degrees C, with R(f) of 94%, R(r) of 98%, and shape recovery within 25s. PCTBV-25 was also shown as a safe material with good biocompatibility by cytotoxicity tests and cell growth experiments. The stent made from PCTBV-25 film showed nearly complete self-expansion at 37 degrees C within only 25 s, which is much better and faster than the best known self-expandable stents. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

A route to quantitative ¹³C NMR analysis of multicomponent polyesters

DEFF Research Database (Denmark)

Hvilsted, S.

1991-01-01

A protocol for quantitative sequential 13C NMR analysis is developed for polyesters composed of trimethylol propane (TMP), neopentyl glycol (NPG), and adipic and isophthalic acids. TMP centred, structural models with methyl adipate and isophthalate branches in all possible combinations...

Silica in situ enhanced PVA/chitosan biodegradable films for food packages.

Science.gov (United States)

Yu, Zhen; Li, Baoqiang; Chu, Jiayu; Zhang, Peifeng

2018-03-15

Non-degradable plastic food packages threaten the security of environment. The cost-effective and biodegradable polymer films with good mechanical properties and low permeability are very important for food packages. Among of biodegradable polymers, PVA/chitosan (CS) biodegradable films have attracted considerable attention because of feasible film forming ability. However, PVA/CS biodegradable films suffered from poor mechanical properties. To improve mechanical properties of PVA/CS biodegradable films, we developed SiO 2 in situ to enhance PVA/CS biodegradable films via hydrolysis of sodium metasilicate in presence of PVA and chitosan solution. The tensile strength of PVA/CS biodegradable films was improved 45% when 0.6 wt.% SiO 2 was incorporated into the films. Weight loss of PVA/CS biodegradable films was 60% after 30 days in the soil. The permeability of oxygen and moisture of PVA/CS biodegradable films was reduced by 25.6% and 10.2%, respectively. SiO 2 in situ enhanced PVA/CS biodegradable films possessed not only excellent mechanical properties, but also barrier of oxygen and water for food packages to extend the perseveration time. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis of biodegradable styrene copolymers

OpenAIRE

Gevers, Dries; Kobben, Stephan; Junkers, Tanja; Copinet, Alain; Buntinx, Mieke; Peeters, Roos

2017-01-01

Polystyrene (PS), a versatile polymer with many applications (e.g. packaging) representing about 10% of the total annual polymer consumption, shows practically no biodegradability. In this study a styrene (ST) based copolymer is synthesized and examined regarding its ability to degrade in a composting test. As second monomer, to introduce biodegradable ester groups, 5,6-benzo-2-metylene-dioxepane (BMDO) has been used in radical copolymerization reactions performed in inert and stirred 10 m...

The transport of 3H and 14C in phloem strands of Heracleum lanatum and polyester threads

International Nuclear Information System (INIS)

Hoddinott, J.; Gorham, P.R.

1976-01-01

Experiments are described which show a great similarity in the profiles of rapid movement of tritium after external application of 3 H 2 O to a small segment of a phloem strand of Heracleum lanatum and a water-soaked polyester thread. Efflux of rapidly transported tritium from phloem strands and polyester threads was also similar. No rapid movement of radioisotope from (U- 14 C)sucrose, (6,6'- 3 H)sucrose, or (6- 3 H)glucose along phloem strands was observed. A possible explanation for the rapid movement of tritium in terms of proton transfer is offered. It is concluded that the rapid movement of tritium in a phloem strand which occurs when 3 H 2 O is applied externally to a segment is an artifact and that no normal translocation is occurring. (author)

The influence of solvent processing on polyester bioabsorbable polymers.

Science.gov (United States)

Manson, Joanne; Dixon, Dorian

2012-01-01

Solvent-based methods are commonly employed for the production of polyester-based samples and coatings in both medical device production and research. The influence of solvent casting and subsequent drying time was studied using thermal analysis, spectroscopy and weight measurement for four grades of 50 : 50 poly(lactic-co-glycolic acid) (PLGA) produced by using chloroform, dichloromethane, and acetone. The results demonstrate that solvent choice and PLGA molecular weight are critical factors in terms of solvent removal rate and maintaining sample integrity, respectively. The protocols widely employed result in high levels of residual solvent and a new protocol is presented together with solutions to commonly encountered problems.

Degradation Mechanisms of Poly(ester urethane) Elastomer

Energy Technology Data Exchange (ETDEWEB)

Edgar, Alexander S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-11-30

This report describes literature regarding the degradation mechanisms associated with a poly(ester urethane) block copolymer, Estane® 5703 (Estane), used in conjunction with Nitroplasticizer (NP), and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane, also known as high molecular weight explosive (HMX) to produce polymer bonded explosive PBX 9501. Two principal degradation mechanisms are reported: NO2 oxidative reaction with the urethane linkage resulting in crosslinking and chain scission events, and acid catalyzed hydrolysis of the ester linkage. This report details future work regarding this PBX support system, to be conducted in late 2017 and 2018 at Engineered Materials Group (MST-7), Materials Science and Technology Division, Los Alamos National Laboratory. This is the first of a series of three reports on the degradation processes and trends of the support materials of PBX 9501.

Novel Zinc-Catalytic Systems for Ring-Opening Polymerization of ε-Caprolactone

Directory of Open Access Journals (Sweden)

Karolina Żółtowska

2015-02-01

Full Text Available Polycaprolactone (PCL is a biodegradable synthetic polymer that is currently widely used in many pharmaceutical and medical applications. In this paper we describe the coordination ring-opening polymerization of ε-caprolactone in the presence of two newly synthesized catalytic systems: diethylzinc/gallic acid and diethylzinc/propyl gallate. The chemical structures of the obtained PCLs were characterized by 1H- or 13C-NMR, FTIR spectroscopy and MALDI TOF mass spectrometry. The average molecular weight of the resulting polyesters was analysed by gel permeation chromatography and a viscosity method. The effects of temperature, reaction time and type of catalytic system on the polymerization process were examined. Linear PCLs with defined average molecular weight were successfully obtained. Importantly, in some cases the presence of macrocyclic products was not observed during the polymerization process. This study provides an effective method for the synthesis of biodegradable polyesters for medical and pharmaceutical applications due to the fact that gallic acid/propyl gallate are commonly used in the pharmaceutical industry.

Comparison of the efficacy of biodegradable and non-biodegradable scintillation liquids on the counting of tritium- and [14C]-labeled compounds

Directory of Open Access Journals (Sweden)

Medeiros R.B.

2003-01-01

Full Text Available The widespread use of ³H and 14C in research has generated a large volume of waste mixed with scintillation liquid, requiring an effective control and appropriate storage of liquid radioactive waste. In the present study, we compared the efficacy of three commercially available scintillation liquids, Optiphase HiSafe 3, Ultima-Gold(TM AB (biodegradable and Insta-Gel-XF (non-biodegradable, in terms of [14C]-glucose and [³H]-thymidine counting efficiency. We also analyzed the effect of the relative amount of water (1.6 to 50%, radioisotope concentration (0.1 to 100 nCi/ml, pH (2 to 10 and color of the solutions (samples containing 0.1 to 1.0 mg/ml of Trypan blue on the counting efficiency in the presence of these scintillation liquids. There were few significant differences in the efficiency of 14C and ³H counting obtained with biodegradable or non-biodegradable scintillation liquids. However, there was an 83 and 94% reduction in the efficiency of 14C and ³H counting, respectively, in samples colored with 1 mg/ml Trypan blue, but not with 0.1 mg/ml, independent of the scintillation liquid used. Considering the low cost of biodegradable scintillation cocktails and their efficacy, these results show that traditional hazardous scintillation fluids may be replaced with the new safe biodegradable fluids without impairment of ³H and 14C counting efficiency. The use of biodegradable scintillation cocktails minimizes both human and environmental exposure to hazardous solvents. In addition, some biodegradable scintillation liquids can be 40% less expensive than the traditional hazardous cocktails.

Hyperbranched polyester: single route synthesis, characterization and evaluation as impact modifier of an epoxy resin; Poliester hiperramificado: sintese por uma rota simples, caracterizacao e avaliacao como modificador de impacto de uma resina epoxi

Energy Technology Data Exchange (ETDEWEB)

Miranda, B.H.S.; Sousa, A.R., E-mail: rangel@deii.cefetmg.br [Centro Federal de Educacao Tecnologica de Minas Gerais (DEMAT/CEFET-MG), Belo Horizonte (Brazil). Departamento de Engenharia de Materiais; Alves, A.P.P.; Silva, G.G. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Departamento de Quimica. Lab. de Materiais Polimericos Multicomponentes

2015-07-01

Two hyperbranched polyesters were obtained using glycerol and adipic acid as monomers, they were characterized through nuclear magnetic resonance ({sup 13}C NMR) to branching degree determination, size exclusion chromatography to molar mass obtention and thermogravimetric analysis (TGA) to evaluate the thermal stability. The polyesters synthesized were added to epoxy resin, at 10% by weight, to evaluate the implication on mechanical properties, impact and stress strain, and thermal (glassy transition temperature - Tg). We observed that rising the synthesis time from 6 to 15,5 hours the degree of branching, molar mass and thermal stability of the polyester increased. The addition of hyperbranched polyesters did not change the mechanical properties of epoxy resin significantly, but the Tg was reduced. (author)

Quasi-static puncture resistance behaviors of high-strength polyester fabric for soft body armor

Directory of Open Access Journals (Sweden)

Qiu-Shi Wang

Full Text Available A series of economical and flexible fabrics were prepared using high-strength polyester yarns with different fabric structures, weft density and number of layers. The effect of these factors on quasi-static puncture resistance was comparatively studied. The failure mode of the fabrics was analyzed with SEM photographs. Findings indicate that the structure and the weft density affected the quasi-static puncture resistance property of the fabrics, the plain fabrics had better puncture resistance property than twill and satin fabrics. The max puncture force and puncture energy of the plain fabrics with 160 yarn/10 cm reached the max values which were 107.43 N and 0.44 J, respectively. The number of layers had a linear relationship to quasi-static puncture resistance. The contact pressure and friction of the probe against the fibers were the main hindrance during the quasi-static puncture process and the breakage of the fibers during the penetration was caused by the bend and tensile deformation. Keywords: High-strength polyester fabrics, Fabric structure, Multiple-layer fabrics, Quasi-static puncture resistance

Characterization of biodegradation intermediates of nonionic surfactants by MALDI-MS. 2. Oxidative biodegradation profiles of uniform octylphenol polyethoxylate in 18O-labeled water.

Science.gov (United States)

Sato, Hiroaki; Shibata, Atsushi; Wang, Yang; Yoshikawa, Hiromichi; Tamura, Hiroto

2003-01-01

This paper reports the characterization of the biodegradation intermediates of octylphenol octaethoxylate (OP(8)EO) by means of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The biodegradation test study was carried out in a pure culture (Pseudomonas putida S-5) under aerobic conditions using OP(8)EO as the sole carbon source and (18)O-labeled water as an incubation medium. In the MALDI-MS spectra of biodegraded samples, a series of OP(n)EO molecules with n = 2-8 EO units and their corresponding carboxylic acid products (OP(n)EC) were observed. The use of purified OP(8)EO enabled one to distinguish the shortened OPEO molecules as biodegradation intermediates. Furthermore, the formation of OP(8)EC (the oxidized product of OP(8)EO) supported the notion that terminal oxidation is a step in the biodegradation process. When biodegradation study was carried out in (18)O-labeled water, incorporation of (18)O atoms into the carboxyl group was observed for OPEC, while no incorporation was observed for the shortened OPEO products. These results could provide some rationale to the biodegradation mechanism of alkylphenol polyethoxylates.

Partially Biodegradable Distraction Implant to Replace Conventional Implants in Alveolar Bone of Insufficient Height: A Preliminary Study in Dogs.

Science.gov (United States)

Li, Tao; Zhang, Yongqiang; Shao, Bo; Gao, Yuan; Zhang, Chen; Cao, Qiang; Kong, Liang

2015-12-01

Dental implants have been widely used in the last few decades. However, patients with insufficient bone height need reconstructive surgeries before implant insertion. The distraction implant (DI) has been invented to simplify the treatment procedure, but the shortcomings of DIs have limited their clinical use. We incorporated biodegradable polyester into a novel DI called the partially biodegradable distraction implant (PBDI). The purpose of this study was to assess the radiological, histological, and biomechanical properties of the PBDI in animal models. PBDIs were manufactured and inserted into the atrophied mandibles of nine dogs. Box-shaped alveolar bones were segmented and distracted. The dogs were randomly divided into three groups that were sacrificed 1, 2, and 3 months after the implant insertion. Actual augmentation height (AAH) of the bone segments was measured to evaluate the effect of distraction. X-ray examination and micro-CT reconstruction and analysis were used to evaluate the regenerated bone in the distraction gap and bone around the functional element. Histological sections were used to evaluate the osseointegration and absorption of the PBDI. Fatigue tests were used to evaluate the biomechanical properties of the PBDI. Little change was found in AAH among the three groups. X-ray examination and micro-CT reconstruction showed good growth of regenerated bone in the distraction gap. Alveolar bone volume around the functional element increased steadily. No obvious bone absorption occurred in the alveolar crest around PBDI. Three months after distraction, the functional element achieved osseointegration, and the support element began to be absorbed. All PBDIs survived the fatigue test. The PBDI is a novel and reliable dental implant. It becomes a conventional implant after the absorption of the support element and the removal of the distraction screw. It is a promising replacement for conventional implants in patients with insufficient alveolar bone

Study on transparency of adhesive joints of scintillation strips on the polyester basis

International Nuclear Information System (INIS)

Bondarenko, V.G.; Grigor'ev, V.A.; Kaplin, V.A.; Gushchin, V.V.; Prikhodchenko, N.N.; Silina, T.S.; Finashina, T.L.

1979-01-01

Optical transparency of adhesive joints of polyester-base scintillators is studied. To realize the optical contact between two scintillation strips of the 400x80x20 mm and 300x80x20 mm dimensions the following substances are used: KV-3 vaseline, 21-03V elastosyl adhesive and VK-14 adhesive. Using an installation for measuring adhesive joint transparency the dependence of the photomultiplier signal amplitude on the β-source coordinates is obtained. It is experimentally found that light losses on the adhesive joints were 8% for the VK-14 and elastosyl adhesives, and 10% for the VK-3 vase-line. The measurement error is +-1%. On the basis of the results obtained the conclusion is made that for adhesion of the scintillation detectors on the polyester basis the 21-03V elastosyl for detachable joints and the VK-14 adhesive - for permanent joints adhesive can be used. It is noted that while using the VK-14 adhesive it is necessary to pay attention to thorough preparation of the adhesive surfaces and provision of the necessary pressure during adhesion (not less than 2-3 kg/cm 2 ) [ru

Preparation and Characterization of Waterborne Polyurethaneurea Composed of Dimer Fatty Acid Polyester Polyol

Directory of Open Access Journals (Sweden)

2006-01-01

Full Text Available A series of polyurethaneurea (PUU aqueous dispersions, which were stable at ambient temperature for more than 1 year, were prepared with C 36 -dimer-fatty-acid-based polyester polyol, isophorone diisocyanate, dimethylol propionic acid, and ethylenediamine. The particle size of all these PUU (DPU aqueous dispersions ( <100 nm was less than that of comparable specimens, that is, poly-(neopentyl glycol adipate polyester-polyol-based PUU (APU aqueous dispersions, and the polydispersity index was very narrow ( ≤1.13 . The films prepared with the DPU aqueous dispersions exhibited excellent waterproof performance, such as low amount of water absorption (1.3 wt%, and good mechanical properties (hardness and tensile strength, resulting from the strong hydrogen bonding in urea carbonyl groups and the perfect ordered structure of hard segments compared with those prepared with the APU aqueous dispersions. The surface hydrophobicity of the films prepared with modified DPU aqueous dispersions, which were modified with a fluorinated polyacrylate emulsion, was excellent, as the water contact angle on the surface of such films rose up to 100. The mechanical properties of such modified DPU films were further enhanced.

The role of the substrate in micro-scale scratching of epoxy-polyester films

Science.gov (United States)

Barletta, M.; Gisario, A.

2011-02-01

The present investigation analyzes the deformation response of electrostatically sprayed epoxy-polyester powder coatings by 'in situ' micro-mechanical tests. The characterization of the performance of the coatings was carried out by micro-scale scratching, by varying the indenter type, the applied load and the sliding speed. The tests were carried out on polymeric coatings deposited on as-received, micro and macro-corrugated AISI 304 stainless steel substrates and 'rigidly adhered' to them. Further tests were performed on 'free-standing' coatings, that is, on the as-received metal substrates pre-coated with an intermediate layer of silicon-based heat curable release coating. Experimental data allow us to evaluate the influence of the contact conditions between substrate and indenter and the role of the loading conditions on the scratch and penetration resistance of the epoxy-polyester coatings. The different responses of the polymeric coatings when deposited on untreated or pre-treated substrates as well as on an intermediate layer of release coating, contribute to a better understanding of the intrinsic roles of the polymeric material and substrate as well as the influence of the interfacial adhesion between coating and substrate.

Research regarding biodegradable properties of food polymeric products under microorganism activity

Science.gov (United States)

Opran, Constantin; Lazar, Veronica; Fierascu, Radu Claudiu; Ditu, Lia Mara

2018-02-01

Aim of this research is the structural analysis by comparison of the biodegradable properties of two polymeric products made by non-biodegradable polymeric material (polypropylene TIPPLEN H949 A) and biodegradable polymeric material (ECOVIO IS 1335), under microorganism activity in order to give the best solution for the manufacture of food packaging biodegradable products. It presents the results of experimental determinations on comparative analysis of tensile strength for the two types of polymers. The sample weight variations after fungal biodegradation activity revealed that, after 3 months, there are no significant changes in polymeric substratum for non-biodegradable polymeric. The microscopically analysis showed that the fungal filaments did not strongly adhered on the non-biodegradable polymeric material, instead, both filamentous fungi strains adhered and covered the surface of the biodegradable sample with germinated filamentous conidia. The spectral analysis of polymer composition revealed that non-biodegradable polymer polypropylene spectra are identical for control and for samples that were exposed to fungal activity, suggesting that this type of sample was not degraded by the fungi strains. Instead, for biodegradable polymer sample, it was observed significant structural changes across multiple absorption bands, suggesting enzyme activity manifested mainly by Aspergillus niger strain. Structural analysis of interdisciplinary research results, lead, to achieving optimal injection molded technology emphasizing technological parameters, in order to obtain food packaging biodegradable products.

Comparison of storage stability of odorous VOCs in polyester aluminum and polyvinyl fluoride tedlar bags

Science.gov (United States)

Whole air sampling using containers such as flexible bags or rigid canisters is commonly used to collect samples of volatile organic compounds (VOC) in air. The objective of this study was to compare the stability of polyester aluminum (PEA) and polyvinyl fluoride (PVF, brand name Tedlar®) bags for ...

Final Report: Development of Renewable Microbial Polyesters for Cost Effective and Energy- Efficient Wood-Plastic Composites

Energy Technology Data Exchange (ETDEWEB)

Thompson, David N.; Emerick, Robert W.; England, Alfred B.; Flanders, James P.; Loge, Frank J.; Wiedeman, Katherine A.; Wolcott, Michael P.

2010-03-31

In this project, we proposed to produce wood fiber reinforced thermoplastic composites (WFRTCs) using microbial thermoplastic polyesters in place of petroleum-derived plastic. WFRTCs are a rapidly growing product area, averaging a 38% growth rate since 1997. Their production is dependent on substantial quantities of petroleum based thermoplastics, increasing their overall energy costs by over 230% when compared to traditional Engineered Wood Products (EWP). Utilizing bio-based thermoplastics for these materials can reduce our dependence on foreign petroleum. We have demonstrated that biopolymers (polyhydroxyalkanoates, PHA) can be successfully produced from wood pulping waste streams and that viable wood fiber reinforced thermoplastic composite products can be produced from these materials. The results show that microbial polyester (PHB in this study) can be extruded together with wastewater-derived cell mass and wood flour into deck products having performance properties comparable to existing commercial HDPE/WF composite products. This study has thus proven the underlying concept that the microbial polyesters produced from waste effluents can be used to make cost-effective and energy-efficient wood-plastic composites. The cost of purified microbial polyesters is about 5-20 times that of HDPE depending on the cost of crude oil, due to high purification (40%), carbon substrate (40%) and sterilized fermentation (20%) costs for the PHB. Hence, the ability to produce competitive and functional composites with unpurified PHA-biomass mixtures from waste carbon sources in unsterile systems—without cell debris removal—is a significant step forward in producing competitive value-added structural composites from forest products residuals using a biorefinery approach. As demonstrated in the energy and waste analysis for the project, significant energy savings and waste reductions can also be realized using this approach. We recommend that the next step for development of

Proton-Transfer Polymerization by N-Heterocyclic Carbenes: Monomer and Catalyst Scopes and Mechanism for Converting Dimethacrylates into Unsaturated Polyesters

KAUST Repository

Hong, Miao

2016-01-18

This contribution presents a full account of experimental and theoretical/computational investigations into the N-heterocyclic carbene (NHC)-catalyzed proton-transfer polymerization (HTP) that converts common dimethacrylates (DMAs) containing no protic groups into unsaturated polyesters. This new HTP proceeds through the step-growth propagation cycles via enamine intermediates, consisting of the proposed conjugate addition–proton transfer–NHC release fundamental steps. This study examines the monomer and catalyst scopes as well as the fundamental steps involved in the overall HTP mechanism. DMAs having six different types of linkages connecting the two methacrylates have been polymerized into the corresponding unsaturated polyesters. The most intriguing unsaturated polyester of the series is that based on the biomass-derived furfuryl dimethacrylate, which showed a unique self-curing ability Four MeO– and Cl–substituted TPT (1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene) derivatives as methanol insertion products, RxTPT(MeO/H) (R = MeO, Cl; x = 2, 3), and two free carbenes (catalysts), OMe2TPT and OMe3TPT, have been synthesized, while OMe2TPT(MeO/H) and OMe2TPT have also been structurally characterized. The structure/reactivity relationship study revealed that OMe2TPT, being both a strong nucleophile and a good leaving group, exhibits the highest HTP activity and also produced the polyester with the highest Mn, while the Cl–substituted TPT derivatives are least active and efficient. Computational studies have provided mechanistic insights into the tail-to-tail dimerization coupling step as a suitable model for the propagation cycle of the HTP. The extensive energy profile was mapped out and the experimentally observed unicity of the TPT-based catalysts was satisfactorily explained with the thermodynamic formation of key spirocyclic species.

Photo and biocatalytic activities along with UV protection properties on polyester fabric through green in-situ synthesis of cauliflower-like CuO nanoparticles.

Science.gov (United States)

Rezaie, Ali Bashiri; Montazer, Majid; Rad, Mahnaz Mahmoudi

2017-11-01

In this paper, a facile environmentally friendly method is introduced for in-situ synthesis and fabrication of cauliflower-like CuO nanoparticles on the polyester fabric to produce photo and biocatalytic activities with UV protection properties on polyester fabric. The ash of burnt leaves and stems of Seidlitzia rosmarinus plant called Keliab was used as a natural and nontoxic alkaline source for simultaneous synthesis of CuO nanoparticles and surface modification of polyester without using any other compounds. The images of field-emission scanning electron microscopy, patterns of energy-dispersive spectroscopy, UV-visible spectrum and X-ray diffraction confirmed successful synthesis and loading of CuO nanoparticles on the polyester fabric. The treated fabrics showed very good antibacterial activities toward two pathogen bacteria including Staphylococcus aureus as a Gram-positive and Escherichia coli as a Gram-negative bacteria with no adverse effects on human dermal fibroblasts based on MTT test. The treated fabrics confirmed significant photocatalytic activity for degradation of methylene blue under sunlight, self-cleaning properties under UV light and also UV protection properties. Further a colorant effect along with an improvement in the wettability and mechanical properties of the treated fabrics were indicated. Overall, this method can be applied as a clean route for producing photo and bio active textiles protecting against UV irradiation. Copyright © 2017 Elsevier B.V. All rights reserved.

Primary biodegradation of petroleum hydrocarbons in seawater

Energy Technology Data Exchange (ETDEWEB)

Comber, M.I.H.; Den Haan, K.H.; Djemel, N.; Eadsforth, C.V.; King, D.; Paumen, M.L.; Parkerton, T.; Dmytrasz, B.

2012-12-15

This report describes primary biodegradation experiments performed to determine the persistence of higher molecular weight petroleum hydrocarbons in seawater. Results from the biodegradation experiments show that the majority of tested petroleum hydrocarbons have half-lives in seawater less than 60 days.

Simultaneous adsorption and biodegradation of synthetic melanoidin

African Journals Online (AJOL)

Being an antioxidant, melanoidin removal through purely biodegradation has been inadequate. Consequently, in the current study, simultaneous adsorption and biodegradation (SAB) was employed in a stirred tank system to remove melanoidin from synthetic wastewater. Mixed microbial consortium was immobilized onto ...

Oil biodegradation

NARCIS (Netherlands)

Rahsepar, Shokouhalsadat; Langenhoff, Alette A.M.; Smit, Martijn P.J.; Eenennaam, van Justine S.; Murk, Tinka; Rijnaarts, Huub H.M.

2017-01-01

During the Deepwater Horizon (DwH) oil spill, interactions between oil, clay particles and marine snow lead to the formation of aggregates. Interactions between these components play an important, but yet not well understood, role in biodegradation of oil in the ocean water. The aim of this study

An analysis of the anisotropic and topographic gratings in a side-chain liquid crystalline azobenzene polyester

DEFF Research Database (Denmark)

Holme, N.C.R.; Nikolova, L.; Ramanujam, P.S.

1997-01-01

We have examined in detail the formation of surface relief structures in azobenzene polyesters formed by polarization holography with orthogonally circularly polarized laser beams, We show that it is possible to separate the contribution to the diffraction efficiency into an anisotropic part...

A versatile family of degradable non-viral gene carriers based on hyperbranched poly(ester amine)s

NARCIS (Netherlands)

Zhong, Zhiyuan; Song, Y.; Engbersen, Johannes F.J.; Lok, Martin C.; Hennink, Wim E.; Feijen, Jan

2005-01-01

A variety of degradable hyperbranched poly(ester amine)s containing primary, secondary and tertiary amino groups, were synthesized and evaluated as non-viral gene carriers. The polymers were obtained in high yields through a Michael-type conjugate addition of diacrylate monomers with trifunctional

State-of-the-art of biodegradable composite materials

International Nuclear Information System (INIS)

Baley, Ch.; Grohens, Y.; Pillin, I.

2004-01-01

Nowadays, the market demand for environment friendly materials is in strong growth. The biodegradable composites (biodegradable fibres and polymers) mainly extracted from renewable resources will be a major contributor to the production of new industrial high performance products partially solving the problem of waste management. At the end of the lifetime, a structural bio-composite could be be crushed and recycled through a controlled industrial composting process. This the state-of-the-art report focuses on the biopolymers the vegetable fibres properties, the mechanisms of biodegradation and the examples of biodegradable composites. Eco-design of new products requires these new materials for which a life cycle analysis is nevertheless necessary to validate their environmental benefits. (authors)

"Rational" management of dichlorophenols biodegradation by the microalga Scenedesmus obliquus.

Science.gov (United States)

Papazi, Aikaterini; Kotzabasis, Kiriakos

2013-01-01

The microalga Scenedesmus obliquus exhibited the ability to biodegrade dichlorophenols (dcps) under specific autotrophic and mixotrophic conditions. According to their biodegradability, the dichlorophenols used can be separated into three distinct groups. Group I (2,4-dcp and 2,6 dcp - no meta-substitution) consisted of quite easily degraded dichlorophenols, since both chloride substituents are in less energetically demanding positions. Group II (2,3-dcp, 2,5-dcp and 3,4-dcp - one meta-chloride) was less susceptible to biodegradation, since one of the two substituents, the meta one, required higher energy for C-Cl-bond cleavage. Group III (3,5-dcp - two meta-chlorides) could not be biodegraded, since both chlorides possessed the most energy demanding positions. In general, when the dcp-toxicity exceeded a certain threshold, the microalga increased the energy offered for biodegradation and decreased the energy invested for biomass production. As a result, the biodegradation per cell volume of group II (higher toxicity) was higher, than group I (lower toxicity) and the biodegradation of dichlorophenols (higher toxicity) was higher than the corresponding monochlorophenols (lower toxicity). The participation of the photosynthetic apparatus and the respiratory mechanism of microalga to biodegrade the group I and the group II, highlighted different bioenergetic strategies for optimal management of the balance between dcp-toxicity, dcp-biodegradability and culture growth. Additionally, we took into consideration the possibility that the intermediates of each dcp-biodegradation pathway could influence differently the whole biodegradation procedures. For this reason, we tested all possible combinations of phenolic intermediates to check cometabolic interactions. The present contribution bring out the possibility of microalgae to operate as "smart" bioenergetic "machines", that have the ability to continuously "calculate" the energy reserves and "use" the most energetically

Additional Equipment for Soil Biodegradation

Science.gov (United States)

Vondráčková, Terezie; Kraus, Michal; Šál, Jiří

2017-12-01

Intensification of industrial production, increasing citizens’ living standards, expanding the consumer assortment mean in the production - consumption cycle a constantly increasing occurrence of waste material, which by its very nature must be considered as a source of useful raw materials in all branches of human activity. In addition to strict legislative requirements, a number of circumstances characterize waste management. It is mainly extensive transport associated with the handling and storage of large volumes of substances with a large assortment of materials (substances of all possible physical and chemical properties) and high demands on reliability and time coordination of follow-up processes. Considerable differences in transport distances, a large number of sources, processors and customers, and not least seasonal fluctuations in waste and strong price pressures cannot be overlooked. This highlights the importance of logistics in waste management. Soils that are contaminated with oil and petroleum products are hazardous industrial waste. Methods of industrial waste disposal are landfilling, biological processes, thermal processes and physical and chemical methods. The paper focuses on the possibilities of degradation of oil pollution, in particular biodegradation by bacteria, which is relatively low-cost among technologies. It is necessary to win the fight with time so that no ground water is contaminated. We have developed two additional devices to help reduce oil accident of smaller ranges. In the case of such an oil accident, it is necessary to carry out the permeability test of contaminated soil in time and, on this basis, to choose the technology appropriate to the accident - either in-sit biodegradation - at the site of the accident, or on-sit - to remove the soil and biodegrade it on the designated deposits. A special injection drill was developed for in-sit biodegradation, tossing and aeration equipment of the extracted soil was developed for

Going greener: Synthesis of fully biobased unsaturated polyesters for styrene crosslinked resins with enhanced thermomechanical properties

Directory of Open Access Journals (Sweden)

C. S. M. F. Costa

2017-11-01

Full Text Available The main goal of this work was the development of fully biobased unsaturated polyesters (UPs that upon crosslinking with unsaturated monomers (UM could lead to greener unsaturated polyester resins (UPRs with similar thermomechanical properties to commercial fossil based UPR. After the successful synthesis of the biobased UPs, those were crosslinked with styrene (Sty, the most commonly used monomer, and the influence of the chemical structure of the UPs on the thermomechanical characteristics of UPRs were evaluated. The properties were compared with those of a commercial resin (Resipur 9837©. The BioUPRs presented high gel contents and contact angles that are similar to the commercial resin. The thermomechanical properties were evaluated by dynamic mechanical thermal analysis (DMTA and it was found that the UPR synthesized using propylene glycol (PG, succinic acid (SuAc and itaconic acid (ItAc presented very close thermomechanical properties compared to the commercial resin.

Preparation and characterization of polymer blends based on recycled PET and polyester derived by terephthalic acid

International Nuclear Information System (INIS)

Ohara, L.; Miranda, C.S.; Fiuza, R.P.; Luporini, S.; Carvalho, R.F.; Jose, N.M.

2010-01-01

Environmentally friendly materials, made from industrial waste, are being increasingly used as a solution to the growing amount of waste generated by society, but also as a cheaper alternative to replace conventional materials for use in construction. In this work were investigated the properties of polymer blends based on recycled PET and a polyester derived from terephthalic acid and glycerin, a co-product of biodiesel. The samples were characterized by XRD, TGA, DSC, FTIR and SEM. The polyester synthesized showed a degradation event near 300 deg C. The blends with higher ratio of PET showed thermal behavior similar to pure PET. The X-ray diffraction showed that the polymer blends are semicrystalline materials. The micrographs presents the presence of a smooth surface, indicating the possibility of miscibility between the arrays. Therefore, the blending makes possible the fabrication of low-cost materials with applications in several areas. (author)

Bioavailability and biodegradation kinetics of organics in soil

International Nuclear Information System (INIS)

Tabak, H.H.; Govind, R.; Gao, Chao; Kim, In-soo; Lai, Lei

1992-01-01

As EPA begins to remediate Superfund sites using permanent treatment technologies, such as bioremediation, a fundamental understanding of the kinetics and the factors that control the rate of bioremediation will be required. Biological treatment technologies hold considerable promise for safe, economical, on-site treatment of toxic wastes. A variety of biological treatment systems designed to degrade or detoxify environmental contaminants are currently being developed and marketed. Knowledge of the kinetics of biodegradation is essential to the evaluation of the persistence of most organic pollutants in soil. Furthermore, measurement of biodegradation kinetics can provide useful insights into the favorable range of the important environmental parameters for improvement of the microbiological activity and consequently the enhancement of contaminant biodegradation. A major effort is currently underway to clean up aquifers and soils that are contaminated by organic chemicals, which has generated increased interest in the development of in situ bioremediation technologies. Although considerable data exists for rates of biodegradation in aquatic environments, there is little information on biodegradation kinetics in soil matrices, where irreversible binding to the soil phase may limit the chemicals bioavailability and ultimate degradation. Knowledge on biodegradation kinetics in soil environments can facilitate decisions on the efficacy of in situ bioremediation. 6 refs., 3 figs., 2 tabs

Synthesis and characterization of polyesters derived from glycerol and phthalic acid

Directory of Open Access Journals (Sweden)

Danilo Hansen Guimarães

2007-09-01

Full Text Available The production of polyester via polycondensation between glycerol and phthalic acid using dibutyltin dilaurate is reported. Three glycerol:phthalic acid molar ratio used for the bulk polymerization were: 2:2; 2:3 and 2:4. FTIR confirmed the esterification of glycerol by the acid for all the polymers. DSC indicated no crystallinity, although the XRD plots indicate a very incipient crystallinity for the polymers containing higher amounts of phthalic anhydride. Scanning electron microscopy results indicates high homogeneity for all the polymers prepared.

Optimization of Cutting Parameters on Delamination of Drilling Glass-Polyester Composites

Directory of Open Access Journals (Sweden)

Majid Habeeb Faidh-Allah

2018-02-01

Full Text Available This paper attempted to study the effect of cutting parameters (spindle speed and feed rate on delamination phenomena during the drilling glass-polyester composites. Drilling process was done by CNC machine with 10 mm diameter of high-speed steel (HSS drill bit. Taguchi technique with L16 orthogonal layout was used to analyze the effective parameters on delamination factor. The optimal experiment was no. 13 with spindle speed 1273 rpm and feed 0.05 mm/rev with minimum delamination factor 1.28.

Cyclodextrin-enhanced biodegradation of phenanthrene

Energy Technology Data Exchange (ETDEWEB)

Wang, J.-M.; Marlowe, E.M.; Miller-Maier, R.M.; Brusseau, M.L. [University of Arizona, Tuscon, AZ (United States). Dept. of Soil, Water and Environmental Science

1998-07-01

The effectiveness of in situ bioremediation in many systems may be constrained by low contaminant bioavailability due to limited aqueous solubility or a large magnitude of sorption. The objective of this research was to evaluate the effect of hydroxypropyl-{beta}-cyclodextrin (HPCD) on phenanthrene solubilization and biodegradation. Results showed that analytical-grade HPCD can significantly increase the apparent solubility of phenanthrene. The increase in apparent solubility had a major impact on the biodegradation rate of phenanthrene. For example, in the presence of 10{sup 5} mg L{sup -1} HPCD, the substrate utilization rate increased from 0.17 mg h{sup -1} to 0.93 mg h{sup -1} while the apparent solubility was increased from 1.3 mg L{sup -1} to 161.3 mg L{sup -1}. As a result, only 0.3% of the phenanthrene remained at the end of a 48 h incubation for the highest concentration of HPCD tested (10{sup 5} mg L{sup -1}). In contrast, 45.2% of the phenanthrene remained in the absence of HPCD. Technical-grade HPCD, which contains the biodegradable impurity propylene glycol, also increased the substrate utilization rate, although to a lesser extent than the analytical-grade HPCD. On the basis of these results, it appears that HPCD can significantly increase the bioavailability, and thereby enhance the biodegradation of phenanthrene. 26 refs., 5 figs.

Biodegradation of PuEDTA and Impacts on Pu Mobility

International Nuclear Information System (INIS)

Xun, Luying; Bolton, Jr. Harvey

2001-01-01

Ethylenediaminetetraacetate (EDTA) and nitrilotriacetate (NTA) are synthetic chelating agents, which can form strong water-soluble complexes with radionuclides and metals and has been used to decontaminate and process nuclear materials. Synthetic chelating agents were co-disposed with radionuclides (e.g., 60Co, Pu) and heavy metals enhancing their transport in the subsurface. An understanding of EDTA biodegradation is essential to help mitigate enhanced radionuclide transport by EDTA. The objective of this research is to develop fundamental data on factors that govern the biodegradation of radionuclide-EDTA. These factors include the dominant EDTA aqueous species, the biodegradation of various metal-EDTA complexes, the uptake of various metal-EDTA complexes into the cell, the distribution and mobility of the radionuclide during and after EDTA biodegradation, and the enzymology and genetics of EDTA biodegradation

76 FR 52935 - Certain Polyester Staple Fiber From Korea: Rescission of Antidumping Duty Administrative Review

Science.gov (United States)

2011-08-24

... conform to the Department's revised 19 CFR 351.303(g) certification language as announced in Certification... the correct certification language in a timely manner. On June 28, 2011, in accordance with 19 CFR 351... polyesters measuring 3.3 decitex (3 denier, inclusive) or more in diameter. This merchandise is cut to...

Influence of modified polyester on the material properties of collagen-based biocomposites and in vitro evaluation of cytocompatibility

Energy Technology Data Exchange (ETDEWEB)

Wu, Chin-San, E-mail: t50008@cc.kyu.edu.tw

2015-03-01

The cytocompatibility of composite materials collagen (Col)/poly(hydroxyalkanoate) (PHA) and collagen/maleic anhydride-grafted PHA (PHA-g-MA) was investigated in this study. Col was homogeneously dispersed in the PHA-g-MA matrix as a result of condensation reactions. Mechanical characterisation indicated that the improved adhesion between Col and PHA-g-MA enhanced the tensile strength of the composite compared with that of PHA/Col. PHA-g-MA/Col composites were also more water-resistant than PHA/Col composites. Collagen and cell proliferation analysis indicated that PHA and PHA-g-MA and their composites were biocompatible with respect to FB proliferation. Cell-cycle and apoptosis assays by FBs on the PHA series composite samples were not affected by DNA content related to damage, i.e. rapid apoptosis/necrosis was not observed, demonstrating the potential of PHA/Col or PHA-g-MA/Col membranes for biomedical material applications. - Highlights: • Composites were prepared using polyester and collagen to explore their cytocompatibility. • The mechanical properties of the composite were significantly enhanced by the use of grafted polyester and collagen. • The polyester and collagen composites facilitated excellent cell viability and collagen production. • The cell cycle was not affected by DNA content related to damage, and it did not lead to rapid apoptosis or necrosis of the cells by the composite.

Influence of modified polyester on the material properties of collagen-based biocomposites and in vitro evaluation of cytocompatibility

International Nuclear Information System (INIS)

Wu, Chin-San

2015-01-01

The cytocompatibility of composite materials collagen (Col)/poly(hydroxyalkanoate) (PHA) and collagen/maleic anhydride-grafted PHA (PHA-g-MA) was investigated in this study. Col was homogeneously dispersed in the PHA-g-MA matrix as a result of condensation reactions. Mechanical characterisation indicated that the improved adhesion between Col and PHA-g-MA enhanced the tensile strength of the composite compared with that of PHA/Col. PHA-g-MA/Col composites were also more water-resistant than PHA/Col composites. Collagen and cell proliferation analysis indicated that PHA and PHA-g-MA and their composites were biocompatible with respect to FB proliferation. Cell-cycle and apoptosis assays by FBs on the PHA series composite samples were not affected by DNA content related to damage, i.e. rapid apoptosis/necrosis was not observed, demonstrating the potential of PHA/Col or PHA-g-MA/Col membranes for biomedical material applications. - Highlights: • Composites were prepared using polyester and collagen to explore their cytocompatibility. • The mechanical properties of the composite were significantly enhanced by the use of grafted polyester and collagen. • The polyester and collagen composites facilitated excellent cell viability and collagen production. • The cell cycle was not affected by DNA content related to damage, and it did not lead to rapid apoptosis or necrosis of the cells by the composite

Characterization and Engineering of a Plastic Degrading Aromatic Polyesterase

Energy Technology Data Exchange (ETDEWEB)

Beckham, Gregg T [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Donohoe, Bryon S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rorrer, Nicholas [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Silveira, Rodrigo [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dominick, Graham [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Michener, William E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Amore, Antonella [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Crowley, Michael F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Johnson, Christopher W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Austin, Harry P. [University of Portsmouth; Allen, Mark S. [University of Portsmouth; Thorne, Alan W. [University of Portsmouth; McGeehan, John E. [University of Portsmouth; Kearns, Fiona [University of South Florida; Pollard, Benjamin [University of South Florida; Duman, Ramona [Diamond Light Source; El Omari, Kamel [Diamond Light Source; Mykhaylyk, Vitaliy [Diamond Light Source; Wagner, Armin [Diamond Light Source; Woodcock, H. Lee [University of South Florida; Skaf, Munir S. [University of Campinas

2018-04-17

Poly(ethylene terephthalate) (PET) is one of the most abundantly produced synthetic polymers and is accumulating in the environment at a staggering rate as discarded packaging and textiles. The properties that make PET so useful also endow it with an alarming resistance to biodegradation, likely lasting centuries in the environment. Our collective reliance on PET and other plastics means that this buildup will continue unless solutions are found. Recently, a newly discovered bacterium, Ideonella sakaiensis 201-F6, was shown to exhibit the rare ability to grow on PET as a major carbon and energy source. Central to its PET biodegradation capability is a secreted PETase (PET-digesting enzyme). Here, we present a 0.92 A resolution X-ray crystal structure of PETase, which reveals features common to both cutinases and lipases. PETase retains the ancestral a/..beta..-hydrolase fold but exhibits a more open active-site cleft than homologous cutinases. By narrowing the binding cleft via mutation of two active-site residues to conserved amino acids in cutinases, we surprisingly observe improved PET degradation, suggesting that PETase is not fully optimized for crystalline PET degradation, despite presumably evolving in a PET-rich environment. Additionally, we show that PETase degrades another semiaromatic polyester, polyethylene-2,5-furandicarboxylate (PEF), which is an emerging, bioderived PET replacement with improved barrier properties. In contrast, PETase does not degrade aliphatic polyesters, suggesting that it is generally an aromatic polyesterase. These findings suggest that additional protein engineering to increase PETase performance is realistic and highlight the need for further developments of structure/activity relationships for biodegradation of synthetic polyesters.

Characterization and engineering of a plastic-degrading aromatic polyesterase.

Science.gov (United States)

Austin, Harry P; Allen, Mark D; Donohoe, Bryon S; Rorrer, Nicholas A; Kearns, Fiona L; Silveira, Rodrigo L; Pollard, Benjamin C; Dominick, Graham; Duman, Ramona; El Omari, Kamel; Mykhaylyk, Vitaliy; Wagner, Armin; Michener, William E; Amore, Antonella; Skaf, Munir S; Crowley, Michael F; Thorne, Alan W; Johnson, Christopher W; Woodcock, H Lee; McGeehan, John E; Beckham, Gregg T

2018-05-08

Poly(ethylene terephthalate) (PET) is one of the most abundantly produced synthetic polymers and is accumulating in the environment at a staggering rate as discarded packaging and textiles. The properties that make PET so useful also endow it with an alarming resistance to biodegradation, likely lasting centuries in the environment. Our collective reliance on PET and other plastics means that this buildup will continue unless solutions are found. Recently, a newly discovered bacterium, Ideonella sakaiensis 201-F6, was shown to exhibit the rare ability to grow on PET as a major carbon and energy source. Central to its PET biodegradation capability is a secreted PETase (PET-digesting enzyme). Here, we present a 0.92 Å resolution X-ray crystal structure of PETase, which reveals features common to both cutinases and lipases. PETase retains the ancestral α/β-hydrolase fold but exhibits a more open active-site cleft than homologous cutinases. By narrowing the binding cleft via mutation of two active-site residues to conserved amino acids in cutinases, we surprisingly observe improved PET degradation, suggesting that PETase is not fully optimized for crystalline PET degradation, despite presumably evolving in a PET-rich environment. Additionally, we show that PETase degrades another semiaromatic polyester, polyethylene-2,5-furandicarboxylate (PEF), which is an emerging, bioderived PET replacement with improved barrier properties. In contrast, PETase does not degrade aliphatic polyesters, suggesting that it is generally an aromatic polyesterase. These findings suggest that additional protein engineering to increase PETase performance is realistic and highlight the need for further developments of structure/activity relationships for biodegradation of synthetic polyesters. Copyright © 2018 the Author(s). Published by PNAS.

Study on the morphology and thermomechanical properties of poly(urethane-siloxane) networks based on hyperbranched polyester

Czech Academy of Sciences Publication Activity Database

Pergal, M. V.; Džunuzović, J. V.; Špírková, Milena; Poreba, Rafal; Steinhart, Miloš; Pergal, M. M.; Ostojić, S.

2013-01-01

Roč. 67, č. 6 (2013), s. 871-879 ISSN 0367-598X R&D Projects: GA ČR GAP108/10/0195 Institutional support: RVO:61389013 Keywords : polyurethane networks * poly(dimethylsiloxane) * hyperbranched polyester Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.562, year: 2013

Joep van Lieshout's Mobile Home for Kröller-Müller: outdoor polyester sculpture in transit

NARCIS (Netherlands)

Stigter, S.; Beerkens, L.; Schellen, H.L.; Kuperholc, S.; Bridgland, J.

2008-01-01

The nature and condition of the large scale glass fibre reinforced polyester resin outdoor sculpture by Dutch artist Joep van Lieshout: Mobile Home for Kröller-Müller (1995) is challenging traditional conservation ethics. Chemists, physicists, art historians, conservators specialised in different

Effect of Hydroxyl Monomers on the Enzymatic Degradation of Poly(ethylene succinate, Poly(butylene succinate, and Poly(hexylene succinate

Directory of Open Access Journals (Sweden)

Zhenhui Bai

2018-01-01

Full Text Available Poly(ethylene succinate (PES, poly(butylene succinate (PBS, and poly(hexylene succinate (PHS, were synthesized using succinic acid and different dihydric alcohols as materials. Enzymatic degradability by cutinase of the three kinds of polyesters was studied, as well as their solid-state properties. The biodegradation behavior relied heavily on the distance between ester groups, crystallinity, and the hydrophilicity-hydrophobicity balance of polyester surfaces. The weight loss through degradation of the three kinds of polyesters with different hydroxyl monomers took place in the order PHS > PBS > PES. The degradation behavior of the polyesters before and after degradation was analyzed by scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, Fourier transform infrared spectroscopy, gel permeation chromatography, and thermogravimetric analysis. The decrease in relative intensity at 1800–1650 estedpolyesters were degraded simultaneously. The frequencies of the crystalline and amorphous bands were almost identical before and after degradation. Thus, enzymatic degradation did not change the crystalline structure but destroyed it, and the degree of crystallinity markedly decreased. The molecular weight and polydispersity index only changed slightly. The thermal stability of the three kinds of polyesters decreased during enzymatic degradation.

The second green revolution? Production of plant-based biodegradable plastics.

Science.gov (United States)

Mooney, Brian P

2009-03-01

Biodegradable plastics are those that can be completely degraded in landfills, composters or sewage treatment plants by the action of naturally occurring micro-organisms. Truly biodegradable plastics leave no toxic, visible or distinguishable residues following degradation. Their biodegradability contrasts sharply with most petroleum-based plastics, which are essentially indestructible in a biological context. Because of the ubiquitous use of petroleum-based plastics, their persistence in the environment and their fossil-fuel derivation, alternatives to these traditional plastics are being explored. Issues surrounding waste management of traditional and biodegradable polymers are discussed in the context of reducing environmental pressures and carbon footprints. The main thrust of the present review addresses the development of plant-based biodegradable polymers. Plants naturally produce numerous polymers, including rubber, starch, cellulose and storage proteins, all of which have been exploited for biodegradable plastic production. Bacterial bioreactors fed with renewable resources from plants--so-called 'white biotechnology'--have also been successful in producing biodegradable polymers. In addition to these methods of exploiting plant materials for biodegradable polymer production, the present review also addresses the advances in synthesizing novel polymers within transgenic plants, especially those in the polyhydroxyalkanoate class. Although there is a stigma associated with transgenic plants, especially food crops, plant-based biodegradable polymers, produced as value-added co-products, or, from marginal land (non-food), crops such as switchgrass (Panicum virgatum L.), have the potential to become viable alternatives to petroleum-based plastics and an environmentally benign and carbon-neutral source of polymers.

10,000 optical write, read, and erase cycles in an azobenzene sidechain liquid-crystalline polyester

DEFF Research Database (Denmark)

Holme, NCR; Ramanujam, P.S.; Hvilsted, Søren

1996-01-01

We show far what is believed to he the first time that it is possible tu generate 10,000 rapid write, read, and erase cycles optically in an azobenzene sidechain liquid-crystalline polyester. We do this by exposing the film alternately to visible light from an argon laser at 488 nm and ultraviolet...

Phyllosphere yeasts rapidly break down biodegradable plastics.

Science.gov (United States)

Kitamoto, Hiroko K; Shinozaki, Yukiko; Cao, Xiao-Hong; Morita, Tomotake; Konishi, Masaaki; Tago, Kanako; Kajiwara, Hideyuki; Koitabashi, Motoo; Yoshida, Shigenobu; Watanabe, Takashi; Sameshima-Yamashita, Yuka; Nakajima-Kambe, Toshiaki; Tsushima, Seiya

2011-11-29

The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands.

Phyllosphere yeasts rapidly break down biodegradable plastics

Science.gov (United States)

2011-01-01

The use of biodegradable plastics can reduce the accumulation of environmentally persistent plastic wastes. The rate of degradation of biodegradable plastics depends on environmental conditions and is highly variable. Techniques for achieving more consistent degradation are needed. However, only a few microorganisms involved in the degradation process have been isolated so far from the environment. Here, we show that Pseudozyma spp. yeasts, which are common in the phyllosphere and are easily isolated from plant surfaces, displayed strong degradation activity on films made from poly-butylene succinate or poly-butylene succinate-co-adipate. Strains of P. antarctica isolated from leaves and husks of paddy rice displayed strong degradation activity on these films at 30°C. The type strain, P. antarctica JCM 10317, and Pseudozyma spp. strains from phyllosphere secreted a biodegradable plastic-degrading enzyme with a molecular mass of about 22 kDa. Reliable source of biodegradable plastic-degrading microorganisms are now in our hands. PMID:22126328

Radiation curable coatings from palm oil acrylated polyester prepolymer

International Nuclear Information System (INIS)

Azam Ali, M.; Ooi, T.L.; Salmiah, A.; Ishiaku, U.S.; Mohd Ishak, Z.A.

2002-01-01

Radiation (ultra-violet, UV) curable coatings were prepared by using palm oil acrylated polyester prepolymer (PEPP-1) in combination with different reactive diluents in the presence of photoinitiator Irgacure 184 (Irg184). The effects of viscosity of coating materials, radiation dose and curing behavior were investigated. The UV cured polymeric films properties such as pendulum hardness, wettability (contact angle), gel ,content, swelling character, tensile strength, elongation at break, and deformation stability were then determined. The optimum formulations were also coated on wood substrates after which the gloss and hardness of the cured film on the wood substrate were measured. Some formulations showed promising coatings properties and has a good potential application for the wood coating industry. (Author)

Improvement of biodegradability of industrial wastewaters by radiation treatment

International Nuclear Information System (INIS)

Jo, H.J.; Kim, H.J.; Kim, J.G.; Jung, J.; Choi, J.S.; Park, Y.K.

2006-01-01

In order to evaluate the use of gamma-ray treatment as a pretreatment to conventional biological methods, the effects of gamma-irradiation on biodegradability (BOD 5 /COD) of textile and pulp wastewaters were investigated. For all wastewaters studied in this work, the efficiency of treatment based on TOC removal was insignificant even at an absorbed dose of 20 kGy. However, the change of biodegradability was noticeable and largely dependent on the chemical property of wastewaters and the absorbed dose of gamma-rays. For textile wastewaters, gamma-ray treatment increased the biodegradability of desizing effluent due to degradation of polymeric sizing agents such as polyvinyl alcohol. Interestingly, the weight-loss showed the highest value of 0.97 at a relatively low dose of 1 kGy. This may be caused by the degradation of less biodegradable ethylene glycol prior to terephthalic acid decomposition. For pulp wastewater, the gamma-ray treatment did not improve the biodegradability of cooking and bleaching of C/D effluents. However, the biodegradability of bleaching E1 and final effluents was abruptly increased up to 5 kGy then slowly decreased as the absorbed dose was increased. The initial increase of biodegradability may be induced by the decomposition of refractory organic compounds such as chlorophenols, which are known to be the main components of bleaching C/D and final effluents. (author)

50-Hz plasma treatment of glass fibre reinforced polyester at atmospheric pressure enhanced by ultrasonic irradiation

DEFF Research Database (Denmark)

Kusano, Yukihiro; Norrman, Kion; Singh, Shailendra Vikram

2011-01-01

Glass fibre reinforced polyester (GFRP) plates are treated using a 50-Hz dielectric barrier discharge at peak-to-peak voltage of 30 kV in helium at atmospheric pressure with and without ultrasonic irradiation to study adhesion improvement. The ultrasonic waves at the fundamental frequency of around...

One-pot preparation of unsaturated polyester nanocomposites containing functionalized graphene sheets via a novel solvent-exchange method

Science.gov (United States)

This paper reports a convenient one-pot method integrating a novel solvent-exchange method into in situ melt polycondensation to fabricate unsaturated polyester nanocomposites containing functionalized graphene sheets (FGS). A novel solvent-exchange method was first developed to prepare graphene oxi...

Biodegradation of penicillin-G wastewater using Phanerochate ...

African Journals Online (AJOL)

SERVER

2007-06-18

Jun 18, 2007 ... emission of toxic substances and formation of sludge. In recent years, a white rot fungus, ... sporium as a potential microorganism for the biodegrade- tion of polychlorinated ... 1990), paper mill bleach plant effluent (Fukui, 1992) and spentwash (Fahy et al., ..... Studies on biodegradation of toxic compounds.

Magnetic Cobalt and Cobalt Oxide Nanoparticles in Hyperbranched Polyester Polyol Matrix

Directory of Open Access Journals (Sweden)

O. I. Medvedeva

2017-01-01

Full Text Available A series of cobalt (Co and its oxides based nanoparticles were synthesized by using hyperbranched polyester polyol Boltorn H20 as a platform and sodium borohydride as a reducing agent. UV, FT-IR, XRD, NTA, and TEM methods were employed to obtain physicochemical characteristics of the products. The average diameter of Co nanoparticles was approximately 8.2±3.4 nm. Their magnetic properties, including hysteresis loop, field-cooled, and zero field-cooled curves were investigated. The nanoparticles exhibit superparamagnetism at room temperature, accompanied by magnetic hysteresis below the blocking temperature.

Biodegradable magnesium-alloy stent:current situation in research

International Nuclear Information System (INIS)

Chen Hua; Zhao Xianxian

2011-01-01

In recent years, permanent metal stents are employed in the majority of interventional therapies; nevertheless, such kind of stents carries the problems of thrombosis and restenosis. Therefore, the biodegradable magnesium alloy stent has become the focus of attention. Theoretically, it has overcome the problems caused by permanent metal stents, so it is the development direction to use the biodegradable magnesium alloy in future. The authors believe that biodegradable magnesium alloy stents will be widely used in interventional procedures for many diseases. (authors)

Biodegradation of 4-nitroaniline by plant-growth promoting Acinetobacter sp. AVLB2 and toxicological analysis of its biodegradation metabolites

Energy Technology Data Exchange (ETDEWEB)

Silambarasan, Sivagnanam [Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Vangnai, Alisa S., E-mail: alisa.v@chula.ac.th [Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok 10330 (Thailand)

2016-01-25

Highlights: • Acinetobacter sp. AVLB2 is a PGPB able to degrade high concentration of 4-NA. • Growth and degradation kinetics for 4-NA removal by AVLB2 were studied. • A novel biodegradation pathway for 4-nitroaniline has been proposed. • Toxicological studies revealed non-toxic nature of 4-NA biodegraded metabolites. • Acinetobacter sp. AVLB2 could maintain PGP traits under 4-NA stress. - Abstract: 4-nitroaniline (4-NA) is one of the major priority pollutants generated from industrial productions and pesticide transformation; however very limited biodegradation details have been reported. This work is the first to report 4-NA biodegradation kinetics and toxicity reduction using a newly isolated plant-growth promoting bacterium, Acinetobacter sp. AVLB2. The 4-NA-dependent growth kinetics parameters: μ{sub max}, K{sub s} and K{sub i}, were determined to be 0.039 h{sup −1}, 6.623 mg L{sup −1} and 25.57 mg L{sup −1}, respectively using Haldane inhibition model, while the maximum biodegradation rate (V{sub max}) of 4-NA was at 0.541 mg L{sup −1} h{sup −1} and 0.551 mg L{sup −1} h{sup −1}, following Michaelis–Menten and Hanes–Woolf models, respectively. Biodegradation pathway of 4-NA by Acinetobacter sp. AVLB2 was proposed, and successfully led to the reduction of 4-NA toxicity according to the following toxicity assessments: microbial toxicity using Escherichia coli DH5α, phytotoxicity with Vigna radiata and Crotalaria juncea, and cytogenotoxicity with Allium cepa root-tip cells. In addition, Acinetobacter sp. AVLB2 possess important plant-growth promoting traits, both in the presence and absence of 4-NA. This study has provided a new insight into 4-NA biodegradation ability and concurrent plant-growth promoting activities of Acinetobacter sp. AVLB2, which may indicate its potential role for rhizoremediation, while sustaining crop production even under 4-NA stressed environment.

Novel polyester/SiO2 nanocomposite membranes: Synthesis, properties and morphological studies

Science.gov (United States)

Ahmadizadegan, Hashem; Esmaielzadeh, Sheida

2018-06-01

In this paper, a new type of soluble polyester/silica (PE/SiO2) hybrid was prepared by the ultrasonic irradiation process. The coupling agent γ-glycidyloxypropyltrimethoxysilane (GOTMS) was chosen to enhance the compatibility between the polyester (PE) and silica (SiO2). Furthermore, the effects of the coupling agent on the morphologies and properties of the PE/SiO2 hybrids were investigated using UV-vis and FT-IR spectroscopies and FE-SEM. The densities and solubilities of the PE/SiO2 hybrids were also measured. The results show that the size of the silica particle was markedly reduced by the introduction of the coupling agent, which made the PE/SiO2 hybrid films become transparent. Furthermore, thermal stability, residual solvent in the membrane film and structural ruination of membranes were analyzed by thermal gravimetric analysis (TGA). The effects of SiO2 nanoparticles on the glass transition temperature (Tg) of the prepared nanocomposites were studied by differential scanning calorimetry (DSC). Moreover, their mechanical properties were also characterized. It can be observed that the Young's moduli (E) of the hybrid films increase linearly with the silica content. The results obtained from gas permeation experiments with a constant pressure setup showed that adding SiO2 nanoparticles to the polymeric membrane structure increased the permeability of the membranes.

Effect of addition of lignin in physical-chemical properties of a polyesters based on glycerol, phthalic and adipic acids

International Nuclear Information System (INIS)

Guimaraes, D.H.; Viana, A.P.M.; Lima, A.S.C.; Goncalves, A.P.B.; Miranda, C.S.; Jose, N.M.

2014-01-01

In this paper the study of different addition amounts of lignin in the physicochemical properties of polyesters made from glycerol and different amounts of phthalic and adipic acids have been proposed. The following characterizations were made: XRD, FTIR, TGA, DSC and SEM. The variation in the percentage of adipic and phthalic acids had a direct effect on thermal and morphological properties. The thermal analysis showed that there was miscibility between the polyester and lignin, by means of displacement related to the temperature of thermal degradation events. In FTIR analysis was noted displacements of characteristic bands of hydrogen bonds and specific carbonyl ester groups. These shifts were more pronounced as it has larger amounts of phthalic acid as monomer and larger amounts of lignin in the compositions. (author)

Base Oils Biodegradability Prediction with Data Mining Techniques

Directory of Open Access Journals (Sweden)

Malika Trabelsi

2010-02-01

Full Text Available In this paper, we apply various data mining techniques including continuous numeric and discrete classification prediction models of base oils biodegradability, with emphasis on improving prediction accuracy. The results show that highly biodegradable oils can be better predicted through numeric models. In contrast, classification models did not uncover a similar dichotomy. With the exception of Memory Based Reasoning and Decision Trees, tested classification techniques achieved high classification prediction. However, the technique of Decision Trees helped uncover the most significant predictors. A simple classification rule derived based on this predictor resulted in good classification accuracy. The application of this rule enables efficient classification of base oils into either low or high biodegradability classes with high accuracy. For the latter, a higher precision biodegradability prediction can be obtained using continuous modeling techniques.

The Effect Of Coupling Agent On Composite Magnet Characteristic Based On Hexa ferrite (Sr M/Ba M) With Polyester And Epoxy Binder

International Nuclear Information System (INIS)

Sudirman; Ridwan; Mujamilah; Karo Karo, Aloma; Handayani, Ari; Rukihati

2004-01-01

Magnetic composites are mixtures of hexa ferrite powder and non magnetic materials such as polymers as binders. These composites have been investigated because they are light, elastic, and cheap. In this study thermoset polymer (epoxy and polyester) were used as binders. Inside study of coupling agent added effect on mechanical properties, hardness and microstructure. The composites were prepared by mixture thermoset polymer epoxy or polyester with hexa ferrite powder Sr M (SrFe 12 O 19 ) or Ba M (BaFe 12 O 19 ) with volume fraction of 40,50 and 60 % v/v, coupling agent of the Tetra Isopropyl Titanate in the amount of 5 ml or 10 ml are added before mix turing of the thermoset polymer epoxy or polyester with hexa ferrite powder. The resulting composite were characterized mechanically (tensile strength), hardness and microstructure test. The results showed that the tensile strength and hardness of the composite magnet were increased by increasing the composition of magnetic powder, either Sr M or Ba M, it caused by microstructure of particle Sr M magnetic powder 1.6 μm in the form splinter, where as the Ba M magnetic powder 1,2 μm in nodular form. Thermoset polymer epoxy as binder have tensile strength and hardness is bigger than composite magnet based on polyester, either Sr M or Ba M. The addition of coupling agent is very influenced on the tensile strength and hardness composite magnet, the more coupling magnet addition causes the more tensile strength and hardness of the composite magnet

Preparation and Characterization of Poly(lactic acid)/ difatty Acyl urea/ modified Clay Nano composite

International Nuclear Information System (INIS)

Al-Mulla, E.M.A.

2011-01-01

One of the commercially available biodegradable polymer is Poly(lactic acid) (PLA). It is from the family of aliphatic polyesters, which are produced from many renewable resources such as corn and sugar beets. PLA and other biodegradable polymers are readily biodegradable by enzyme action, which have attracted a lot of attention in the scientific community due to a rapid growth of intensive interest in the global environment for alternatives to petroleum-based polymeric materials. Although PLA has good mechanical properties and process ability, its applications are limited due to its brittleness and non flexibility. However, PLA may be used as a biodegradable and renewable plastic for the textile industries, automotive and clinical uses as well as food packaging materials. Since soft and flexible PLA are required to reach end user demands. (author)

Environmental silicate nano-biocomposites

CERN Document Server

Pollet, Eric

2012-01-01

Environmental Silicate Nano-Biocomposites focuses on nano-biocomposites, which are obtained by the association of silicates such as bioclays with biopolymers. By highlighting recent developments and findings, green and biodegradable nano-composites from both renewable and biodegradable polymers are explored. This includes coverage of potential markets such as packaging, agricultures, leisure and the fast food industry. The knowledge and experience of more than twenty international experts in diverse fields, from chemical and biochemical engineering to applications, is brought together in four different sections covering: Biodegradable polymers and Silicates, Clay/Polyesters Nano-biocomposites, Clay/Agropolymers Nano-biocomposites, and Applications and biodegradation of Nano-biocomposites. By exploring the relationships between the biopolymer structures, the processes, and the final properties Environmental Silicate Nano-Biocomposites explains how to design nano-materials to develop new, valuable, environmenta...

Saponification of fatty slaughterhouse wastes for enhancing anaerobic biodegradability.

Science.gov (United States)

Battimelli, Audrey; Carrère, Hélène; Delgenès, Jean-Philippe

2009-08-01

The thermochemical pretreatment by saponification of two kinds of fatty slaughterhouse waste--aeroflotation fats and flesh fats from animal carcasses--was studied in order to improve the waste's anaerobic degradation. The effect of an easily biodegradable compound, ethanol, on raw waste biodegradation was also examined. The aims of the study were to enhance the methanisation of fatty waste and also to show a link between biodegradability and bio-availability. The anaerobic digestion of raw waste, saponified waste and waste with a co-substrate was carried out in batch mode under mesophilic and thermophilic conditions. The results showed little increase in the total volume of biogas, indicating a good biodegradability of the raw wastes. Mean biogas volume reached 1200 mL/g VS which represented more than 90% of the maximal theoretical biogas potential. Raw fatty wastes were slowly biodegraded whereas pretreated wastes showed improved initial reaction kinetics, indicating a better initial bio-availability, particularly for mesophilic runs. The effects observed for raw wastes with ethanol as co-substrate depended on the process temperature: in mesophilic conditions, an initial improvement was observed whereas in thermophilic conditions a significant decrease in biodegradability was observed.

Biodegradable polymers for targeted delivery of anti-cancer drugs.

Science.gov (United States)

Doppalapudi, Sindhu; Jain, Anjali; Domb, Abraham J; Khan, Wahid

2016-06-01

Biodegradable polymers have been used for more than three decades in cancer treatment and have received increased interest in recent years. A range of biodegradable polymeric drug delivery systems designed for localized and systemic administration of therapeutic agents as well as tumor-targeting macromolecules has entered into the clinical phase of development, indicating the significance of biodegradable polymers in cancer therapy. This review elaborates upon applications of biodegradable polymers in the delivery and targeting of anti-cancer agents. Design of various drug delivery systems based on biodegradable polymers has been described. Moreover, the indication of polymers in the targeted delivery of chemotherapeutic drugs via passive, active targeting, and localized drug delivery are also covered. Biodegradable polymer-based drug delivery systems have the potential to deliver the payload to the target and can enhance drug availability at desired sites. Systemic toxicity and serious side effects observed with conventional cancer therapeutics can be significantly reduced with targeted polymeric systems. Still, there are many challenges that need to be met with respect to the degradation kinetics of the system, diffusion of drug payload within solid tumors, targeting tumoral tissue and tumor heterogeneity.

Durability of Starch Based Biodegradable Plastics Reinforced with Manila Hemp Fibers

Directory of Open Access Journals (Sweden)

Shinji Ochi

2011-02-01

Full Text Available The biodegradability of Manila hemp fiber reinforced biodegradable plastics was studied for 240 days in a natural soil and 30 days in a compost soil. After biodegradability tests, weights were measured and both tensile strength tests and microscopic observation were performed to evaluate the biodegradation behavior of the composites. The results indicate that the tensile strength of the composites displays a sharp decrease for up to five days, followed by a gradual decrease. The weight loss and the reduction in tensile strength of biodegradable composite materials in the compost soil are both significantly greater than those buried in natural soil. The biodegradability of these composites is enhanced along the lower portion because this area is more easily attacked by microorganisms.

Durability of Starch Based Biodegradable Plastics Reinforced with Manila Hemp Fibers.

Science.gov (United States)

Ochi, Shinji

2011-02-25

The biodegradability of Manila hemp fiber reinforced biodegradable plastics was studied for 240 days in a natural soil and 30 days in a compost soil. After biodegradability tests, weights were measured and both tensile strength tests and microscopic observation were performed to evaluate the biodegradation behavior of the composites. The results indicate that the tensile strength of the composites displays a sharp decrease for up to five days, followed by a gradual decrease. The weight loss and the reduction in tensile strength of biodegradable composite materials in the compost soil are both significantly greater than those buried in natural soil. The biodegradability of these composites is enhanced along the lower portion because this area is more easily attacked by microorganisms.

Lipase catalyzed HEMA initiated ring-opening polymerization: In situ formation of mixed polyester methacrylates by transesterification

NARCIS (Netherlands)

Takwa, M.; Xiao, Y.; Simpson, N.; Malmstrom, E.; Hult, K.; Koning, C.E.; Heise, A.; Martinelle, M.

2008-01-01

2-Hydroxyethyl methacrylate (HEMA) was used as initiator for the enzymatic ring-opening polymerization (ROP) of ¿-pentadecalactone (PDL) and e-caprolactone (CL). The lipase B from Candida antarctica was found to catalyze the cleavage of the ester bond in the HEMA end group of the formed polyesters,

Metal-free synthesis of novel biobased dihydroxyl-terminated aliphatic polyesters as building blocks for thermoplastic polyurethanes

NARCIS (Netherlands)

Tang, D.; Noordover, B.A.J.; Sablong, R.J.; Koning, C.E.

2011-01-01

Using the organic compound 1,5,7-triazabicyclo[ 4.4.0]dec-5-ene (TBD) as a catalyst for step-growth polymerization, a series of well-defined hydroxyl-telechelic renewable aliphatic polyesters (including poly(1,3-propylene adipate); poly(1,4-butylene adipate); poly(1,12-dodecylene sebacate); and

Polyesters production from the mixture of phthalic acid, terephthalic and glycerol; Producao de poliesteres a partir da mistura de acido ftalico, tereftalico e glicerol

Energy Technology Data Exchange (ETDEWEB)

Carvalho, A.L.S.; Oliveira, J.C.; Miranda, C.S.; Boaventura, J.S.; Jose, N.M., E-mail: adrianaequfba@gmail.co [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais; Carvalho, R.F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Escola Politecnica. Curso de Mestrado em Engenharia Ambiental Urbana

2010-07-01

Glycerin, a byproduct of biodiesel is currently an environmental and economic problem for producers of this renewable fuel in Brazil and in others parts of the world. In order to offer new proposals for recovery, it is used for the manufacture of polyesters used in applications in diverse areas such as construction and automobile industry. This work reports the production of polymer from the mixture of terephthalic and phthalic acid in three different proportions. The polyesters showed good thermal stability, analyzed by TGA and DSC, with an increase proportional to the terephthalic acid content. The X-ray diffraction patterns show that the samples are semi crystalline polymers. The micrographs indicated the presence of a smoother surface in the polyester that has a larger amount of phthalic acid, as reported in the literature. Therefore, the materials showed good thermal properties and morphological characteristics, so it consists in a new alternative to use glycerin. (author)

Miscibility and specific interactions in blends of poly(n-vinyl-2-pyrrolidone) and acid functional polyester resins.

NARCIS (Netherlands)

Senatore, D.; Berix, M.J.A.; Laven, J.; Benthem, van R.A.T.M.; With, de G.; Mezari, B.; Magusin, P.C.M.M.

2008-01-01

Miscibility and intermol. interactions of novel blends of poly(N-vinyl-2-pyrrolidone) (PVP) and acid functional polyester resins (APE) were studied by use of Differential Scanning Calorimetry (DSC), Attenuated Total Reflectance Fourier Transform IR (ATR-FTIR), Cross-Polarization Magic Angle Spinning