Rigid Polyurethane Foam from Glyco lysed Polyethylene Terephthalate Dissolved in Palm-based Polyol

International Nuclear Information System (INIS)

Khairiah Badri; Lily Iliyana Mohd Dawi; Nur Ashikin Abdul Aziz

2013-01-01

An investigation on the thermal and mechanical properties of rigid polyurethane (PU) foam from polyethylene terephthalate (PET) waste (of plastic drinking bottles) was conducted. The PET waste was glyco lysed with ethylene glycol prior to blending with palm based-polyol (PKO-p). This blend was then reacted with 2, 4-methylene diphenyl diisocyanate (MDI) at a ratio of 1:1 to form the PU foam. The incorporation of the glyco lysed PET (g-PET) into the PKO-p was studied at 50, 70 and 100 % w/ w loading. PU foam prepared from 100 % w/ w g-PET (without PKO-p) resulted in PU with high glass transition temperature and mechanical strength. This water-blown foam has molded and core densities of 182 kg m -3 and 179 kg m -3 , respectively, with maximum compressive stress and modulus at 396 kPa and 1920 kPa, respectively. An initial enthalpy value of 3164.8 cal g -1 and a glass transition temperature of 65 degree Celsius were observed. (author)

Bio-Based Polyols from Seed Oils for Water-Blown Rigid Polyurethane Foam Preparation

Directory of Open Access Journals (Sweden)

Paweena Ekkaphan

2016-01-01

Full Text Available The preparation of water-blown rigid polyurethane (RPUR foams using bio-based polyols from sesame seed oil and pumpkin seed oil has been reported. Polyols synthesis involved two steps, namely, hydroxylation and alcoholysis reaction. FTIR, NMR, and ESI-MS were used to monitor the process of the synthesized polyols and their physicochemical properties were determined. The resulting polyols have OH number in the range of 340–351 mg KOH/g. RPUR foams blown with water were produced from the reaction of biopolyols with commercial polymeric methylene diphenyl diisocyanate (PMDI. The proper PUR formulations can be manipulated to produce the desired material applications. These seed oil-based RPUR foams exhibited relatively high compressive strength (237.7–240.2 kPa with the density in the range of 40–45 kg/m3. Additionally, the cell foam morphology investigated by scanning electron microscope indicated that their cellular structure presented mostly polygonal closed cells. The experimental results demonstrate that these bio-based polyols can be used as an alternative starting material for RPUR production.

The Use of Biodiesel Residues for Heat Insulating Biobased Polyurethane Foams

Directory of Open Access Journals (Sweden)

Nihan Özveren

2017-01-01

Full Text Available The commercial and biobased polyurethane foams (PUF were produced and characterized in this study. Commercial polyether polyol, crude glycerol, methanol-free crude glycerol, and pure glycerol were used as polyols. Crude glycerol is byproduct of the biodiesel production, and it is a kind of biofuel residue. Polyol blends were prepared by mixing the glycerol types and the commercial polyol with different amounts, 10 wt%, 30 wt%, 50 wt%, and 80 wt%. All types of polyol blends were reacted with polymeric diphenyl methane diisocyanates (PMDI for the production of rigid foams. Thermal properties of polyurethane foams are examined by thermogravimetric analysis (TGA and thermal conductivity tests. The structures of polyurethane foams were examined by Fourier Transformed Infrared Spectroscopy (FTIR. Changes in morphology of foams were investigated by Scanning Electron Microscopy (SEM. Mechanical properties of polyurethane foams were determined by compression tests. This study identifies the critical aspects of polyurethane foam formation by the use of various polyols and furthermore offers new uses of crude glycerol and methanol-free crude glycerol which are byproducts of biodiesel industry.

Technical characteristics of rigid sprayed PUR and PIR foams used in construction industry

Science.gov (United States)

Gravit, Marina; Kuleshin, Aleksey; Khametgalieva, Elina; Karakozova, Irina

2017-10-01

The article describes the distinctive properties of rigid polyurethane foam and polyisocyanurate (PUR and PIR). A brief review of the research was carried out on their modification with an objective to improve the thermal insulation properties and reducing the combustibility. A comparative analysis of the technical characteristics of rigid PUR and PIR foams of various manufacturers is presented. The problems of the state of the market for the production of polyurethane foam and polyisocyanurate in Russia have been marked. It is established that the further development of the fabrication technology of heat-insulating sprayed rigid PUR and PIR foams requires uniformity of technical characteristics of original components and finished products. Moreover, it requires the creation of unified information base for raw materials and auxiliary materials used in the production of PUR and PIR foam.

Shock absorbing evaluation of the rigid polyurethane foam and styrofoam applied to a small transportation package

International Nuclear Information System (INIS)

Seo, K.S.; Lee, J.C.; Bang, K.S.; Han, H.S.; Chung, S.H.; Choi, B.I.; Ha, J.H.

2004-01-01

The package design objectives for the drop condition are to maintain the integrity of the structural material by reducing the impact force. There are two kinds of the shock absorbing materials such as rigid polyurethane foam (PU) and Styrofoam (EPS: Expanded Poly Styrene). These materials are generally used in small transportation packages. The stress-strain curves were obtained by the compression tests until the PU and EPS reached their lock-up strain. This paper describes that, in the case of a small transportation package of a cylindrical shape, the shock absorbing effects were evaluated by utilizing the compression properties of the PU and EPS foam

Thermal assault and polyurethane foam-evaluating protective mechanisms

International Nuclear Information System (INIS)

Williamson, C.L.; Iams, Z.L.

2004-01-01

Rigid polyurethane foam utilizes a variety of mechanisms to mitigate the thermal assault of a ''regulatory burn''. Polymer specific heat and foam k-factor are of limited usefulness in predicting payload protection. Properly formulated rigid polyurethane foam provides additional safeguards by employing ablative mechanisms which are effective even when the foam has been crushed or fractured as a result of trauma. The dissociative transitions from polymer to gas and char, and the gas transport of heat from inside the package out into the environment are also thermal mitigators. Additionally, the in-situ production of an intumescent, insulative, carbonaceous char, confers thermal protection even when a package's outer steel skin has been breached. In this test program, 19 liter, ''Five gallon'' steel pails are exposed on one end to the flame of an ''Oil Burner'' as described in the US Federal Aviation Administration (FAA) ''Aircraft Materials Fire Test Handbook''. When burning 2 diesel at a nominal rate of 8.39 kg (18.5 pounds)/hr, the burner generates a high emissivity flame that impinges on the pail face with the thermal intensity of a full scale pool-fire environment. Results of these tests, TGA and MDSC analysis on the subject foams are reported, and their relevance to full size packages and pool fires are discussed

Flexible thermoplastic composite of Polyvinyl Butyral (PVB and waste of rigid Polyurethane foam

Directory of Open Access Journals (Sweden)

Marilia Sônego

2015-04-01

Full Text Available This study reports the preparation and characterization of composites with recycled poly(vinyl butyral (PVB and residue of rigid polyurethane foam (PUr, with PUr contents of 20, 35 and 50 wt %, using an extruder equipped with a Maillefer single screw and injection molding. The components of the composites were thermally characterized using differential scanning calorimetry (DSC and thermogravimetry. The composites were evaluated by melt flow index (MFI, tensile and hardness mechanical tests and scanning electron microscopy (SEM. Tg determined by DSC of PVB sample (53 °C indicated the presence of plasticizer (Tg of pure PVB is 70 °C. MFI of the composites indicated a viscosity increase with the PUr content and, as the shear rate was held constant during injection molding, higher viscosities promoted higher shear stresses in the composites, thereby causing breaking or tearing of the PUr particles. The SEM micrographs showed low adhesion between PVB and PUr and the presence of voids, both inherent in the rigid foam and in the interphase PVB-PUr. The SEM micrographs also showed that PVB/PUr (50/50 composite exhibited the smallest particle size and a more homogeneous and compact structure with fewer voids in the interface. The stiffness of the composites increases with addition of the PUr particles, as evidenced in the mechanical tests.

Different catalysts for new polyols for rigid PUR-PIR foams

Directory of Open Access Journals (Sweden)

Liszkowska Joanna

2015-12-01

Full Text Available New polyols were synthesized with 2-hydroxypropane-1.2.3-tricarboxylic acid and butane-1,4-diol (1.4-BD. The synthesis was performed using different catalysts in the amount of 0.1%. Used catalyst: Tyzor TPT, tin(II acetate, sulfuric(IV acid. The fourth reaction was conducted without the use of a catalyst. The polyols’ properties were evaluated with regards to the usefulness in rigid polyurethane-polyisocyanurate (PUR-PIR foams (acid value, density, pH and solubility, FTIR spectra. Based on the research, it was evaluated that only the polyol synthesized using Tyzor TPT (E6 was useful in production of rigid PUR-PIR foams. Its hydroxyl number was 496 mgKOH/g and its viscosity was about 14 552 mPa · s. A series of five foams P6.1–P6.5 was produced with this polyol. Rigid foams test results indicated that the amount of this compound in the foam substantially affects its compressive strength, density and their retention. The foams have low brittleness values.

Polyurethane-Foam Maskant

Science.gov (United States)

Bodemeijer, R.

1985-01-01

Brown wax previously used to mask hardware replaced with polyurethane foam in electroplating and electroforming operations. Foam easier to apply and remove than wax and does not contaminate electrolytes.

Nano-Aramid Fiber Reinforced Polyurethane Foam

Science.gov (United States)

Semmes, Edmund B.; Frances, Arnold

2008-01-01

Closed cell polyurethane and, particularly, polyisocyanurate foams are a large family of flexible and rigid products the result of a reactive two part process wherein a urethane based polyol is combined with a foaming or "blowing" agent to create a cellular solid at room temperature. The ratio of reactive components, the constituency of the base materials, temperature, humidity, molding, pouring, spraying and many other processing techniques vary greatly. However, there is no known process for incorporating reinforcing fibers small enough to be integrally dispersed within the cell walls resulting in superior final products. The key differentiating aspect from the current state of art resides in the many processing technologies to be fully developed from the novel concept of milled nano pulp aramid fibers and their enabling entanglement capability fully enclosed within the cell walls of these closed cell urethane foams. The authors present the results of research and development of reinforced foam processing, equipment development, strength characteristics and the evolution of its many applications.

Producing Lignin-Based Polyols through Microwave-Assisted Liquefaction for Rigid Polyurethane Foam Production

Directory of Open Access Journals (Sweden)

Bai-Liang Xue

2015-02-01

Full Text Available Lignin-based polyols were synthesized through microwave-assisted liquefaction under different microwave heating times (5–30 min. The liquefaction reactions were carried out using polyethylene glycol (PEG-400/glycerol as liquefying solvents and 97 wt% sulfur acid as a catalyst at 140 °C. The polyols obtained were analyzed for their yield, composition and structural characteristics using gel permeation chromatography (GPC, Fourier transform infrared (FT-IR and nuclear magnetic resonance (NMR spectra. FT-IR and NMR spectra showed that the liquefying solvents reacted with the phenol hydroxyl groups of the lignin in the liquefied product. With increasing microwave heating time, the viscosity of polyols was slightly increased and their corresponding molecular weight (MW was gradually reduced. The optimal condition at the microwave heating time (5 min ensured a high liquefaction yield (97.47% and polyol with a suitable hydroxyl number (8.628 mmol/g. Polyurethane (PU foams were prepared by polyols and methylene diphenylene diisocyanate (MDI using the one-shot method. With the isocyanate/hydroxyl group ([NCO]/[OH] ratio increasing from 0.6 to 1.0, their mechanical properties were gradually increased. This study provided some insight into the microwave-assisted liquefied lignin polyols for the production of rigid PU foam.

Time-dependent crashworthiness of polyurethane foam

Science.gov (United States)

Basit, Munshi Mahbubul; Cheon, Seong Sik

2018-05-01

Time-dependent stress-strain relationship as well as crashworthiness of polyurethane foam was investigated under constant impact energy with different velocities, considering inertia and strain-rate effects simultaneously during the impact testing. Even though the impact energies were same, the percentage in increase in densification strain due to higher impact velocities was found, which yielded the wider plateau region, i.e. growth in crashworthiness. This phenomenon is analyzed by the microstructure of polyurethane foam obtained from scanning electron microscopy. The equations, coupled with the Sherwood-Frost model and the impulse-momentum theory, were employed to build the constitutive equation of the polyurethane foam and calculate energy absorption capacity of the foam. The nominal stress-strain curves obtained from the constitutive equation were compared with results from impact tests and were found to be in good agreement. This study is dedicated to guiding designer use polyurethane foam in crashworthiness structures such as an automotive bumper system by providing crashworthiness data, determining the crush mode, and addressing a mathematical model of the crashworthiness.

Polyurethane Foams with Pyrimidine Rings

Directory of Open Access Journals (Sweden)

Kania Ewelina

2014-09-01

Full Text Available Oligoetherols based on pyrimidine ring were obtained upon reaction of barbituric acid with glycidol and alkylene carbonates. These oligoetherols were then used to obtain polyurethane foams in the reaction of oligoetherols with isocyanates and water. The protocol of foam synthesis was optimized by the choice of proper kind of oligoetherol and synthetic composition. The thermal resistance was studied by dynamic and static methods with concomitant monitoring of compressive strength. The polyurethane foams have similar physical properties as the classic ones except their enhanced thermal resistance. They stand long-time heating even at 200°C. Moreover thermal exposition of foams results generally in increase of their compressive strength.

Sorption of heteropoly acids by polyurethane foam

International Nuclear Information System (INIS)

Dmitreinko, S.G.; Goncharova, L.V.; Runov, V.K.; Zakharov, V.N.; Aslanova, L.A.

1997-01-01

Sorption of oxidized and reduced forms of molybdosilicic, molybdophosphoric and molybdovanadophosphoric acids by polyurethane foam based on ethers and esters is studied. On the basis of sorption dependence on solution pH, polyurethane foam type and spectral characteristics of sorbates the suggestion has been made that in the polyurethane foam phase there are two main types of sorbent-sorbate interaction: electrostatic (ion-ion) and with hydrogen bond formation: and it is impossible to determine the contribution of every interaction

High temperature testing of TRUPACT-I materials: Kevlar, honeycomb, rigid polyurethane foam

International Nuclear Information System (INIS)

Hudson, M.L.

1985-12-01

When the Transuranic Package Transporter Model-I (TRUPACT-I) failed to afford sufficient containment after a 35-minute JP-4 fueled open-pool fire, component tests were conducted, in conjunction with analyses, to guide and assess the redesign of TRUPACT-I. Since materials which change phase or combust are difficult to numerically analyze, the component tests determined the behavior of these materials in TRUPACT-I. The component tests approximated the behavior of Kevlar (registered trademark of DuPont), metal honeycomb, and rigid polyurethane foam, as they appear in TRUPACT-I, in an open-pool fire environment. Six series of tests were performed at Sandia's Radiant Heat Facility and one test at the wind-shielded fire test facility (LAARC Chimney). Each test facility was controlled to yield temperatures or heat fluxes equivalent to those measured in the TRUPACT-I, Unit 0, open-pool fire. This extensive series of component tests (34 runs total) provided information on the high-temperature behavior of unique materials which was not previously available or otherwise attainable. The component tests were a timely and cost-effective means of providing the data for the TRUPACT-I redesign

Fiberglass-Reinforced Rigid Polyurethane Expedient Pavement Subject to Simulated F-4 Aircraft Traffic.

Science.gov (United States)

1980-05-01

34 4,. * ., Table B-I. CPR-739 Rigid Polyurethane Foam Component Characteristics [ Cream Time, 120 sec; Rise Time, 13 sec; Cure Time, 24 hr at 750F...INC. E Colic Soil Tech Dept. Pennsauken. NJ SANDIA LABORATORIES Library Div., Livermore CA SCHUPACK ASSOC SO. NORWALK. CT (SCHUPACK) SHELL OIL CO

Flexible Foam Model.

Energy Technology Data Exchange (ETDEWEB)

Neilsen, Michael K.; Lu, Wei-Yang; Werner, Brian T.; Scherzinger, William M.; Lo, Chi S.

2018-03-01

Experiments were performed to characterize the mechanical response of a 15 pcf flexible polyurethane foam to large deformation at different strain rates and temperatures. Results from these experiments indicated that at room temperature, flexible polyurethane foams exhibit significant nonlinear elastic deformation and nearly return to their original undeformed shape when unloaded. However, when these foams are cooled to temperatures below their glass transition temperature of approximately -35 o C, they behave like rigid polyurethane foams and exhibit significant permanent deformation when compressed. Thus, a new model which captures this dramatic change in behavior with temperature was developed and implemented into SIERRA with the name Flex_Foam to describe the mechanical response of both flexible and rigid foams to large deformation at a variety of temperatures and strain rates. This report includes a description of recent experiments. Next, development of the Flex Foam model for flexible polyurethane and other flexible foams is described. Selection of material parameters are discussed and finite element simulations with the new Flex Foam model are compared with experimental results to show behavior that can be captured with this new model.

Adhesion aspects of polyurethane foam sandwich panels.

OpenAIRE

Ng, Simon L.

2016-01-01

Sandwich panels, polyurethane foam sandwiched between two sheets of steel, form the walls and roofs in the construction of buildings. ArcelorMittal is a manufacturer of the steel as well as these finished panels. For this project they combined with a supplier of the polyurethane foams, Huntsman Polyurethanes, to joint-fund a research project investigating the fundamental mechanisms of adhesion, as well as the causes of failures in the product which manifests primarily in two different ways...

40 CFR 63.1293 - Standards for slabstock flexible polyurethane foam production.

Science.gov (United States)

2010-07-01

... polyurethane foam production. 63.1293 Section 63.1293 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1293 Standards for slabstock flexible polyurethane foam production. Each owner or operator of a...

Cylindrical multiwire two-coordinate chamber with foam-polyurethane supporting element

International Nuclear Information System (INIS)

Vakhtin, V.G.; Travkin, V.I.

1988-01-01

Construction and technology of producing the two-coordinate cylindrical chamber with foam-polyurethane supporting element are described. Use of foam-polyurethane permits to reduce the substance quantity at particle path up to 0.2 g/cm 2 . The supporting element represents a foam-polyurethane tube the outside diameter being 126 mm, the thickness - 6.5 mm and the length 600 mm. Special attention was paid to study of elastic properties of foam-polyurethane tubes and to the effect of the chamber working fluid vapors on the tube sizes. It is stated that after a sustained load (3750 N for 6 days) the tube shrinks by 1.25 %. The foam-polyurethane supporting element arranged in 50% argon + 33% methane + 17% methylane mixture didn't change its sizes in the limit of 0.05% for three weeks. The chamber operates under self-qquenching streamer conditions

40 CFR 63.1300 - Standards for molded flexible polyurethane foam production.

Science.gov (United States)

2010-07-01

... polyurethane foam production. 63.1300 Section 63.1300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... CATEGORIES National Emission Standards for Hazardous Air Pollutants for Flexible Polyurethane Foam Production § 63.1300 Standards for molded flexible polyurethane foam production. Each owner or operator of a new...

Characterization of synthesized polyurethane/montmorillonite nanocomposites foams

International Nuclear Information System (INIS)

Ansari, Farahnaz; Njuguna, James; Sachse, Sophia; Kavosh, Masoud; Michalowski, S; Pielichowski, Krzysztof

2014-01-01

Nanophased hybrid composites based on polyurethane/montmorillonite (PU/MMT) have been fabricated. The nanocomposite which was formed by the addition of a polyol premix with 4,4'-diphenylmethane diisocyanate to obtain nanophased polyurethane foams which were then used for fabrication of nanocomposite panels has been shown to have raised strength, stiffness and thermal insulation properties. The nanophased polyurethane foam was characterized by means of scanning electron microscope (SEM), transmission electron microscope (TEM) measurements and X-ray diffraction (XRD). TEM and SEM analysis indicated that nanophased particles are dispersed homogeneously in the polyurethane matrix on the nanometer scale indicating that PU/MMT is an intercalated nanocomposite with a 2-3 nm nanolayer thickness

Flexible polyurethane foams

NARCIS (Netherlands)

2012-01-01

Embodiments of the invention provide for a method of preparing a polyurethane foam, including reacting least one initiator comprising at least two hydroxyl groups with at least one 12-hydroxystearic acid to form at least one polyester polyol, reacting the at least one polyester polyol with at least

Chemical recycling of semi-rigid polyurethane foams by using an eco-friendly and green method

Directory of Open Access Journals (Sweden)

Mir Mohammad Alavi Nikje

2012-07-01

Full Text Available Degradation of integral skin polyurethane foams (ISPUFs was performed using diethylene glycol (DEG/-sorbitol/water ternary green solvent system as an effective polyurethane bond destroying agent in combination with basic catalysts, namely sodium and potassium hydroxides, sodium acetate and sodium carbonate. The effects of studied catalysts were investigated and data showed the high performances of sodium hydroxide in recycling process. After completion of the reactions, appeared split phases contained recycled polyols in the upper phase. Reactions were studied using various DEG/-sorbitol/water ratios and the recovered polyols were characterized and data compared with an authentic sample.

Extraction behavior of uranium(VI) with polyurethane foam

International Nuclear Information System (INIS)

Tingchia Huang; Donghwang Chen; Muchang Shieh; Chingtsven Huang

1992-01-01

The extraction of uranium(VI) from aqueous solution with polyether-based polyurethane (PU) foam was studied. The effects of the kinds and concentrations of nitrate salts, uranium(VI) concentration, temperature, nitric acid concentration, pH, the content of poly(ethylene oxide) in the polyurethane foam, and the ratio of PU foam weight and solution volume on the extraction of uranium(VI) were investigated. The interferences of fluoride and carbonate ions on the extraction of uranium(VI) were also examined, and methods to overcome both interferences were suggested. It was found that no uranium was extracted in the absence of a nitrate salting-out agent, and the extraction behaviors of uranium(IV) with polyurethane foam could be explained in terms of an etherlike solvent extraction mechanism. In addition, the percentage extraction of a multiple stage was also estimated theoretically

Extraction of uranium from aqueous solution by phosphonic acid-imbedded polyurethane foam

International Nuclear Information System (INIS)

Katragadda, S.; Gesser, H.D.; Chow, A.

1997-01-01

Phenylphosphonic acid was imbedded into the matrix of the polyurethane foam during the fabrication process of the polymer. The extraction of uranium by phosphonic acid-imbedded polyurethane foam and blank polyurethane (i.e., foam without phosphonic acid functional groups) was investigated. Phosphonic acid-imbedded foam showed superior extractability of uranium from solutions with pH = 7.0 ± 1.5 over a wide range of temperatures. (author)

Synthesis and optical properties of polyurethane foam modified with silver nanoparticles

International Nuclear Information System (INIS)

Apyari, V V; Volkov, P A; Dmitrienko, S G

2012-01-01

This paper for the first time describes peculiarities of synthesis of polyurethane foam modified with silver nanoparticles as a potential material for optical sensors in analytical chemistry. We found that the unique sorptional properties of polyurethane foam gave an opportunity to perform such a synthesis by two different approaches. The first one was based on sorption of previously synthesized in-solution nanoparticles by polyurethane foam, the second one consisted in preparation of nanoparticles directly in polyurethane foam matrix. This possibility is novel and interesting for practical use because the nanoparticles in polyurethane foam are capable of surface plasmon resonance. The influence of different factors during the synthesis was investigated and the optimal conditions were found. The samples prepared were characterized by diffuse reflectance spectroscopy and scanning electron microscopy. On the basis of the results obtained we first suggested that this material is attractive from the viewpoint of analytical chemistry as a convenient analytical form for determination of oxidants and reductants

Effect of silica nanoparticles on polyurethane foaming process and foam properties

International Nuclear Information System (INIS)

Francés, A B; Bañón, M V Navarro

2014-01-01

Flexible polyurethane foams (FPUF) are commonly used as cushioning material in upholstered products made on several industrial sectors: furniture, automotive seating, bedding, etc. Polyurethane is a high molecular weight polymer based on the reaction between a hydroxyl group (polyol) and isocyanate. The density, flowability, compressive, tensile or shearing strength, the thermal and dimensional stability, combustibility, and other properties can be adjusted by the addition of several additives. Nanomaterials offer a wide range of possibilities to obtain nanocomposites with specific properties. The combination of FPUF with silica nanoparticles could develop nanocomposite materials with unique properties: improved mechanical and thermal properties, gas permeability, and fire retardancy. However, as silica particles are at least partially surface-terminated with Si-OH groups, it was suspected that the silica could interfere in the reaction of poyurethane formation.The objective of this study was to investigate the enhancement of thermal and mechanical properties of FPUF by the incorporation of different types of silica and determining the influence thereof during the foaming process. Flexible polyurethane foams with different loading mass fraction of silica nanoparticles (0-1% wt) and different types of silica (non treated and modified silica) were synthesized. PU/SiO 2 nanocomposites were characterized by FTIR spectroscopy, TGA, and measurements of apparent density, resilience and determination of compression set. Addition of silica nanoparticles influences negatively in the density and compression set of the foams. However, resilience and thermal stability of the foams are improved. Silica nanoparticles do not affect to the chemical structure of the foams although they interfere in the blowing reaction

Degradation mechanism of polyurethane foam induced by electron beam irradiation

International Nuclear Information System (INIS)

Huang Wei; Fu Yibei; Bian Zhishang; He Meiying

2002-01-01

The degradation mechanism of irradiated polyurethane foam has been studied in detail. The changes of chemical structure and micro-phase separation have been determined by DTG. The gas products from irradiated samples are analyzed quantitatively and qualitatively by GC. The degradation mechanism of irradiated polyurethane foam has been deduced according to the experimental results. It provides some basis of the application on the polyurethane in the radiation field

Formulation, Preparation, and Characterization of Polyurethane Foams

Science.gov (United States)

Pinto, Moises L.

2010-01-01

Preparation of laboratory-scale polyurethane foams is described with formulations that are easy to implement in experiments for undergraduate students. Particular attention is given to formulation aspects that are based on the main chemical reactions occurring in polyurethane production. This allows students to develop alternative formulations to…

APPLICATION OF POLYURETHANE FOAM FOR IMPACT ABSORPTION AND THERMAL INSULATION FOR RADIOACTIVE MATERIALS PACKAGINGS

International Nuclear Information System (INIS)

Smith, A; Glenn Abramczyk, G; Paul Blanton, P; Steve Bellamy, S; William Daugherty, W; Sharon Williamson, S

2007-01-01

Polyurethane foam has been widely used as an impact absorbing and thermal insulating material for large radioactive materials packages, since the 1980's. With the adoption of the regulatory crush test requirement, for smaller packages, polyurethane foam has been adopted as a replacement for cane fiberboard, because of its ability to withstand the crush test. Polyurethane foam is an engineered material whose composition is much more closely controlled than that of cane fiberboard. In addition, the properties of the foam can be controlled by controlling the density of the foam. The conditions under which the foam is formed, whether confined or unconfined have an affect on foam properties. The study reported here reviewed the application of polyurethane foam in RAM packagings and compared property values reported in the literature with published property values and test results for foam specimens taken from a prototype 9977 packaging. The study confirmed that, polyurethane foam behaves in a predictable and consistent manner and fully satisfies the functional requirements for impact absorption and thermal insulation

IDENTIFICATION OF CFC AND HCFC SUBSTITUTES FOR BLOWING POLYURETHANE FOAM INSULATION PRODUCTS

Science.gov (United States)

The report gives results of a cooperative effort to identiry chlorofluorocarbons and hydrochlorofluorocarbon substitutes for blowing polyurethane foam insulation products. The substantial ongoing effort is identifying third-generation blowing agets for polyurethane foams to repla...

Optimization of polyurethane foam cube in enhancing the ...

African Journals Online (AJOL)

Attachment of microalgae biomass to polyurethane foam material is believed could reduce the cost and time needed for harvesting process in making it reliable to be used in industry for biodiesel production. This paper aim to optimize the usage of polyurethane for higher attachment of microalgae biomass yield in term of it ...

Study on polyurethane foamed concrete for use in structural applications

Directory of Open Access Journals (Sweden)

Iman Kattoof Harith

2018-06-01

Full Text Available Recently, foamed concrete is being widely used in civil construction and building, because of its high fluidity and settlement, low self-weight and low thermal conductivity. However, it has some major setbacks such as low strength and increased shrinkage at later ages. The strength gain of concrete depends upon several variables; one of these is the curing conditions. This work aims to study the potential production of foamed concrete as a sustainable structural material by varying the curing methods. For this purpose, sample cubes, cylinders and prisms were prepared to find the compressive strength, modulus of elasticity and drying shrinkage at different ages. Samples of the polyurethane foamed concrete cured under four different curing regimes (water, moisture, sealing by membrane-forming curing compound and air curing. At the end of the study, polyurethane foamed concrete used for this study has shown the potential for use in structural applications. Also, the results show that the samples cured by moisture have the highest compressive strength at all ages. Keywords: Polyurethane foamed concrete, Curing conditions, Fly ash, Compressive strength, Static modulus of elasticity drying shrinkage

Reactions of N,N'-bis(2-hydroxyethyl)oxalamide with Ethylene Carbonate and Use of the Obtained Products as Components of Polyurethanes Foams

International Nuclear Information System (INIS)

Niemiec, I.Z.

2010-01-01

N,N'-bis(2-hydroxyethyl)oxalamide (BHEOA) was subject to hydroxy alkylation with ethylene carbonate (EC). By means of instrumental methods (IR, 1H-NMR, MALDI ToF, GC, and GC-MS), an influence of the reaction conditions on structure and compositions of the obtained products was investigated. The hydroxyalkyl and hydroxy alkoxy derivatives of oxalamide (OA) were obtained by reaction of BHEOA with 210-molar excess of ethylene carbonate (EC, 1,3-dioxolane-2-one). The products have a good thermal stability and possess suitable physical properties as substrates for foamed polyurethanes. The obtained products were used in manufacturing the rigid polyurethane foams which possess enhanced thermal stability and good mechanical properties.

Flame Retardants Used in Flexible Polyurethane Foam

Science.gov (United States)

The partnership project on flame retardants in furniture seeks to update the health and environmental profiles of flame-retardant chemicals that meet fire safety standards for upholstered consumer products with polyurethane foam

A multilayered polyurethane foam technique for skin graft immobilization.

Science.gov (United States)

Nakamura, Motoki; Ito, Erika; Kato, Hiroshi; Watanabe, Shoichi; Morita, Akimichi

2012-02-01

Several techniques are applicable for skin graft immobilization. Although the sponge dressing is a popular technique, pressure failure near the center of the graft is a weakness of the technique that can result in engraftment failure. To evaluate the efficacy of a new skin graft immobilization technique using multilayered polyurethane foam in vivo and in vitro. Twenty-six patients underwent a full-thickness skin graft. Multiple layers of a hydrocellular polyurethane foam dressing were used for skin graft immobilization. In addition, we created an in vitro skin graft model that allowed us to estimate immobilization pressure at the center and edges of skin grafts of various sizes. Overall mean graft survival was 88.9%. In the head and neck region (19 patients), mean graft survival was 93.6%. Based on the in vitro outcomes, this technique supplies effective pressure (skin graft. This multilayered polyurethane foam dressing is simple, safe, and effective for skin graft immobilization. © 2011 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

Polyurethane Foams for Thermal Insulation Uses Produced from Castor Oil and Crude Glycerol Biopolyols.

Science.gov (United States)

Carriço, Camila S; Fraga, Thaís; Carvalho, Vagner E; Pasa, Vânya M D

2017-07-02

Rigid polyurethane foams were synthesized using a renewable polyol from the simple physical mixture of castor oil and crude glycerol. The effect of the catalyst (DBTDL) content and blowing agents in the foams' properties were evaluated. The use of physical blowing agents (cyclopentane and n-pentane) allowed foams with smaller cells to be obtained in comparison with the foams produced with a chemical blowing agent (water). The increase of the water content caused a decrease in density, thermal conductivity, compressive strength, and Young's modulus, which indicates that the increment of CO₂ production contributes to the formation of larger cells. Higher amounts of catalyst in the foam formulations caused a slight density decrease and a small increase of thermal conductivity, compressive strength, and Young's modulus values. These green foams presented properties that indicate a great potential to be used as thermal insulation: density (23-41 kg·m -3 ), thermal conductivity (0.0128-0.0207 W·m -1 ·K -1 ), compressive strength (45-188 kPa), and Young's modulus (3-28 kPa). These biofoams are also environmentally friendly polymers and can aggregate revenue to the biodiesel industry, contributing to a reduction in fuel prices.

Effect of the carbonyl iron particles on acoustic absorption properties of magnetic polyurethane foam

Science.gov (United States)

Geng, Jialu; Wang, Caiping; Zhu, Honglang; Wang, Xiaojie

2018-03-01

Elastomeric matrix embedded with magnetic micro-sized particles has magnetically controllable properties, which has been investigated extensively in the last decades. In this study we develop a new magnetically controllable elastomeric material for acoustic applications at lower frequencies. The soft polyurethane foam is used as matrix material due to its extraordinary elastic and acoustic absorption properties. One-step method is used to synthesize polyurethane foam, in which all components including polyether polyols 330N, MDI, deionized water, silicone oil, carbonyl iron particle (CIP) and catalyst are put into one container for curing. Changing any component can induce the change of polyurethane foam's properties, such as physical and acoustic properties. The effect of the content of MDI on acoustic absorption is studied. The CIPs are aligned under extra magnetic field during the foaming process. And the property of polyurethane foam with aligned CIPs is also investigated. Scanning electron microscope (SEM) is used to observe the structure of pore and particle-chain. The two-microphone impedance tube and the transfer function method are used to test acoustic absorption property of the magnetic foams.

Bitumen modified with recycled polyurethane foam for employment in hot mix asphalt

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Miguel Ángel Salas

2018-01-01

Full Text Available A wide variety of modifiers have been applied to bitumen in order to enhance their properties and performance. Among them, polymers have been mainly used. The aim of this paper is to assess the use of polyurethane foam waste as a bitumen modifier for hot mix asphalts. The polyurethane foam is a by-product of the manufacturing of polyurethane for thermal insulation. From a bitumen with a penetration grade of 50/70, various samples with percentages of waste material in weight ranging from 1% to 5% were produced and tested. Samples with 5% of waste material or more became rough and were refused due to their poor workability. A bituminous mixture with modified bitumen with a 4% of polyurethane was manufactured and compared with a sample with the same aggregates and original bitumen. Results in Marshall test showed that a mix with polymer modified bitumen yielded improvements in stability and a lower deformability. This result suggests that the employment of polyurethane foam waste is a promising bitumen modifier, contributing also to recycle waste materials.

Experimental study of polyurethane foam reinforced soil used as a rock-like material

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Eren Komurlu

2015-10-01

Full Text Available In this study, polyurethane foam type thermoset polymerizing, due to chemical reaction between its liquid ingredients, was tested as binder after solidifying and then a rock-like material mixing with a sandy silt type soil was prepared. The uniaxial compressive strengths (UCSs of polyurethane foam reinforced soil specimens were determined for different polyurethane ratios in the mixture. Additionally, a series of tests on slake durability, impact value, freezing–thawing resistance, and abrasion resistance of polyurethane reinforced soil (PRS mixture was conducted. The UCS values over 3 MPa were measured from the PRS specimens. The testing results showed that treated soil can economically become a desirable rock-like material in terms of slake durability and resistances against freezing–thawing, impact effect and abrasion. As another characteristic of the rock-like material made with polyurethane foam, unit volume weight was found to be quite lower than those of natural rock materials.

Detection of halogenated flame retardants in polyurethane foam by particle induced X-ray emission

International Nuclear Information System (INIS)

Maley, Adam M.; Falk, Kyle A.; Hoover, Luke; Earlywine, Elly B.; Seymour, Michael D.; DeYoung, Paul A.; Blum, Arlene; Stapleton, Heather M.; Peaslee, Graham F.

2015-01-01

A novel application of particle-induced X-ray emission (PIXE) has been developed to detect the presence of chlorinated and brominated flame retardant chemicals in polyurethane foams. Traditional Gas Chromatography–Mass Spectrometry (GC–MS) methods for the detection and identification of halogenated flame retardants in foams require extensive sample preparation and data acquisition time. The elemental analysis of the halogens in polyurethane foam performed by PIXE offers the opportunity to identify the presence of halogenated flame retardants in a fraction of the time and sample preparation cost. Through comparative GC–MS and PIXE analysis of 215 foam samples, excellent agreement between the two methods was obtained. These results suggest that PIXE could be an ideal rapid screening method for the presence of chlorinated and brominated flame retardants in polyurethane foams

Detection of halogenated flame retardants in polyurethane foam by particle induced X-ray emission

Energy Technology Data Exchange (ETDEWEB)

Maley, Adam M.; Falk, Kyle A.; Hoover, Luke; Earlywine, Elly B.; Seymour, Michael D. [Department of Chemistry, Hope College, 35 E. 12th Street, Holland, MI 49423 (United States); DeYoung, Paul A. [Department of Physics, Hope College, 27 Graves Place, Holland, MI 49423 (United States); Blum, Arlene [Green Science Policy Institute, Box 5455, Berkeley, CA 94705 (United States); Stapleton, Heather M. [Nicholas School of the Environment, Duke University, LSRC Box 90328, Durham, NC 27708 (United States); Peaslee, Graham F., E-mail: peaslee@hope.edu [Department of Chemistry, Hope College, 35 E. 12th Street, Holland, MI 49423 (United States)

2015-09-01

A novel application of particle-induced X-ray emission (PIXE) has been developed to detect the presence of chlorinated and brominated flame retardant chemicals in polyurethane foams. Traditional Gas Chromatography–Mass Spectrometry (GC–MS) methods for the detection and identification of halogenated flame retardants in foams require extensive sample preparation and data acquisition time. The elemental analysis of the halogens in polyurethane foam performed by PIXE offers the opportunity to identify the presence of halogenated flame retardants in a fraction of the time and sample preparation cost. Through comparative GC–MS and PIXE analysis of 215 foam samples, excellent agreement between the two methods was obtained. These results suggest that PIXE could be an ideal rapid screening method for the presence of chlorinated and brominated flame retardants in polyurethane foams.

Determination of effective thermal conductivity for polyurethane foam by use of fractal method

Institute of Scientific and Technical Information of China (English)

SHI Mingheng; LI Xiaochuan; CHEN Yongping

2006-01-01

The microstructure of polyurethane foam is disordered, which influences the foam heat conduction process significantly. In this paper foam structure is described by using the local area fractal dimension in a certain small range of length scales. An equivalent element cell is constructed based on the local fractal dimensions along the directions parallel and transverse to the heat flux. By use of fractal void fraction a simplified heat conduction model is proposed to calculate the effective thermal conductivity of polyurethane foam. The predicted effective thermal conductivity agrees well with the experimental data.

Isocyanurate: safe substitute for urethane in polymer foams for mine roadways

Energy Technology Data Exchange (ETDEWEB)

Eisner, H.S.; Leger, J.P.

1989-02-01

Rigid polyurethane foam (PU) used for lining roadways or insulating cooling pipes has been involved in several large fires in South African mines. Polyisocyanurate foam when applied to continuous surfaces in a ventilated mine roadway and subjected to a sizeable flame, will ignite and rapidly propagate flame over its surface, with considerable evolution of carbon monoxide, in a manner substantially similar to polyurethane foam. 12 refs.

Managing burn wounds with SMARTPORE Technology polyurethane foam: two case reports.

Science.gov (United States)

Imran, Farrah-Hani; Karim, Rahamah; Maat, Noor Hidayah

2016-05-12

Successful wound healing depends on various factors, including exudate control, prevention of microbial contaminants, and moisture balance. We report two cases of managing burn wounds with SMARTPORE Technology polyurethane foam dressing. In Case 1, a 2-year-old Asian girl presented with a delayed (11 days) wound on her right leg. She sustained a thermal injury from a hot iron that was left idle on the floor. Clinical inspection revealed an infected wound with overlying eschar that traversed her knee joint. As her parents refused surgical debridement under general anesthesia, hydrotherapy and wound dressing using SMARTPORE Technology Polyurethane foam were used. Despite the delay in presentation of this linear thermal pediatric burn injury that crossed the knee joint, the patient's response to treatment and its outcome were highly encouraging. She was cooperative and tolerated each dressing change without the need of supplemental analgesia. Her wound was healed by 24 days post-admission. In Case 2, a 25-year-old Asian man presented with a mixed thickness thermal flame burn on his left leg. On examination, the injury was a mix of deep and superficial partial thickness burn, comprising approximately 3% of his total body surface area. SMARTPORE Technology polyurethane foam was used on his wound; his response to the treatment was very encouraging as the dressing facilitated physiotherapy and mobility. The patient rated the pain during dressing change as 2 on a scale of 10 and his pain score remained the same in every subsequent change. His wound showed evidence of epithelialization by day 7 post-burn. There were no adverse events reported. Managing burn wounds with SMARTPORE Technology polyurethane foam resulted in reduced pain during dressing changes and the successful healing of partial and mixed thickness wounds. The use of SMARTPORE Technology polyurethane foam dressings showed encouraging results and requires further research as a desirable management option in

Generalization of the memory integer model for the analysis of the quasi-static behaviour of polyurethane foams

International Nuclear Information System (INIS)

Jmal, Hamdi; Ju, Ming Lei; Dupuis, Raphael; Aubry, Evelyne

2014-01-01

Polyurethane foam is a cellular material characterized by an interesting mechanical spectrum of properties: low density, capacity to absorb the deformation energy and low stiffness. This spectrum of properties makes polyurethane foam commonly used in many thermal, acoustic and comfort applications. Several models, such as memory, hyper-elastic and pseudo-elastic models have been developed in the literature to describe the mechanical response of polyurethane foam under quasi-static and dynamic test conditions. The main disadvantage of these models is the dependence of their parameters against the test conditions (strain rate, maximum compression level, etc). This affects the general character of their representativeness to the quasi-static and dynamic behaviours of polyurethane foam. The main goal of this article is to implement reliable mechanical model which is able to provide the quasi-static response of the polyurethane foam under different strain rates and large compressive deformation. The dimensional parameters of our model can be expressed by the product of two independent parts; the first contain only the test conditions and the second define the dimensionless and invariant parameters that characterize the foam material. The developed model has been proposed after several experimental studies allowing the apprehension of the quasi-static behaviour (through unidirectional compression tests). The polyurethane foam, under large deformations, exhibits a nonlinear elastic behaviour and viscoelastic behaviour. To assess the ability of our model to be a general representation, three industrial polyurethane foams have been considered.

Characterization of Functionalized Polyurethane Foam for Lead Ion Removal from Water

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Subhashini Gunashekar

2014-01-01

Full Text Available Polyurethane foams functionalized with sulfonic acid groups are used in this study to exchange lead (Pb2+ ions from aqueous solutions. Toluene-2, 4-diisocyanate, 2,6-diisocyanate (TDI was reacted with Polypropylene glycol 1200 (PPG in 2 : 1 molar ratio to form a linear prepolymer. The linear prepolymer was further polymerized using N,N-bis(2-hydroxyethyl-2-aminoethanesulfonic acid (BES, which acts both as a chain extender and an ion-exchanger for Pb2+ ions. The functionalized polyurethane foam was characterized by Fourier transform infrared spectroscopy (FTIR, gel permeation chromatography (GPC, scanning electron microscopy (SEM, and energy dispersive X-ray spectroscopy (EDX. The Pb2+ ion exchange capacity was determined using an Inductively Coupled Plasma Mass Spectrometer (ICP-MS. The maximum Pb2+ ion exchange capacity of the foam was found to be 51 ppb/g from a 100 ppb Pb2+ solution over a period of two hours. In addition, pH analysis was carried out on the foam composition with the best Pb2+ ion removal capacity. The pH results based on two-hour exposures showed that the functionalized polyurethane foam performed better at lower pH levels.

Extraction kinetics of uranium (VI) with polyurethane foam

International Nuclear Information System (INIS)

Huang, Ting-Chia; Chen, Dong-Hwang; Huang, Shius-Dong; Huang, Ching-Tsven; Shieh, Mu-Chang.

1993-01-01

The extraction kinetics of uranium(VI) from aqueous nitrate solution with polyether-based polyurethane foam was investigated in a batch reactor with automatic squeezing. The extraction curves of uranium(VI) concentration in solution vs. extraction time exhibited a rather rapid exponential decay within the first few minutes, followed by a slower exponential decay during the remaining period. This phenomenon can be attributed to the presence of two-phase structure, hard segment domains and soft segment matrix in the polyurethane foam. A two-stage rate model expressed by a superposition of two exponential curves was proposed, according to which the experimental data were fitted by an optimization method. The extraction rate of uranium (VI) was also found to increase with increasing temperature, nitrate concentration, and hydration of the cation of nitrate salt. (author)

Fracture Toughness Evaluation of Space Shuttle External Tank Thermal Protection System Polyurethane Foam Insulation Materials

Science.gov (United States)

McGill, Preston; Wells, Doug; Morgan, Kristin

2006-01-01

Experimental evaluation of the basic fracture properties of Thermal Protection System (TPS) polyurethane foam insulation materials was conducted to validate the methodology used in estimating critical defect sizes in TPS applications on the Space Shuttle External Fuel Tank. The polyurethane foam found on the External Tank (ET) is manufactured by mixing liquid constituents and allowing them to react and expand upwards - a process which creates component cells that are generally elongated in the foam rise direction and gives rise to mechanical anisotropy. Similarly, the application of successive foam layers to the ET produces cohesive foam interfaces (knitlines) which may lead to local variations in mechanical properties. This study reports the fracture toughness of BX-265, NCFI 24-124, and PDL-1034 closed-cell polyurethane foam as a function of ambient and cryogenic temperatures and knitline/cellular orientation at ambient pressure.

Advanced slab polyurethane foam with feather touch; Soft feather urethane foam no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Yamada, Y; Ono, H [Toyota Motor Corp., Aichi (Japan); Mori, A; Yamaguchi, N; Nakamura, T [Bridgestone Corp., Tokyo (Japan)

1997-10-01

Automotive seat plays an important part, which are not only retention of sitting position, but also comfort and high-class feeling. Wadding, which is a part of the seat, is a key component for the sitting comfortableness. This paper is concerned with advanced slab polyurethane foam with feather touch feeling. The compounding of formation, foaming process and reliability of mass production is studied. 2 refs., 10 figs., 3 tabs.

The use of polyurethane foam as an antimicrobial dressing material in hand surgery

Directory of Open Access Journals (Sweden)

Nebil Yesiloglu

2015-12-01

Full Text Available Polyurethane foam is generally used in negative pressure-assisted wound closure therapy. It provides an antimicrobial environment around the wound, while reducing the rate of skin maceration. The authors used polyurethane foam in routine hand dressings after hand surgery operations that were performed for both congenital and acquired purposes. [Hand Microsurg 2015; 4(3.000: 91-92

Thermal, crystallinity and morphological studies of the filled RBD palm kernel oil polyurethane foam

International Nuclear Information System (INIS)

Khairiah Badri; Sahrim Ahmad; Sarani Zakaria

2000-01-01

The synthesis of RBD palm kernel oil (PKO) polyurethane polyol and the polyurethane foam has well been documented. However, less study has been put in discovering the thermal properties and crystallinity of the foam. It is also an initiative to investigate the effect of oil palm empty fruit bunch (EFB) and sorbitol as fillers in the polyurethane (PU) foam to these properties. Thermogravimetric (TGA) investigation of the PKO PU foam was performed to study their decompositions. The semi-crystalline nature of EFB-filled PU was confirmed by x-ray diffratogram and DSC thermogram of glass transition temperature, T g . The x-ray diffraction (XRD) study of the unfilled PU showed a broad amorphous halo, indicative of absence of crystallinity in the polymer, which has been explained as due to strong hydrogen bonding in the hard phase. Overall crystallinity decreases with an increase in the polyester content in agreement with the XRD results. The crystallinity however, increases with the inclusion of EFB in the polyurethane system. This study was followed by the observation of the surface morphologies of the PKO PU foam with and without fillers. The scanning electron micrographs verified the finding on the improved k-factor values. (Author)

Water-Blown Polyurethane Foams Showing a Reversible Shape-Memory Effect

Directory of Open Access Journals (Sweden)

Elena Zharinova

2016-11-01

Full Text Available Water-blown polyurethane (PU foams are of enormous technological interest as they are widely applied in various fields, i.e., consumer goods, medicine, automotive or aerospace industries. The discovery of the one-way shape-memory effect in PU foams provided a fresh impetus for extensive investigations on porous polymeric actuators over the past decades. High expansion ratios during the shape-recovery are of special interest when big volume changes are required, for example to fill an aneurysm during micro-invasive surgery or save space during transportation. However, the need to program the foams before each operation cycle could be a drawback impeding the entry of shape-memory polymeric (SMP foams to our daily life. Here, we showed that a reversible shape-memory effect (rSME is achievable for polyurethane water-blown semicrystalline foams. We selected commercially available crystallizable poly(ε-caprolactone-diols of different molecular weight for foams synthesis, followed by investigations of morphology, thermal, thermomechanical and shape-memory properties of obtained compositions. Densities of synthesized foams varied from 110 to 180 kg∙m−3, while peak melting temperatures were composition-dependent and changed from 36 to 47 °C, while the melting temperature interval was around 15 K. All semicrystalline foams exhibited excellent one-way SME with shape-fixity ratios slightly above 100% and shape-recovery ratios from the second cycle of 99%. The composition with broad distribution of molecular weights of poly(ε-caprolactone-diols exhibited an rSME of about 12% upon cyclic heating and cooling from Tlow = 10 °C and Thigh = 47 °C. We anticipate that our experimental study opens a field of systematic investigation of rSMEs in porous polymeric materials on macro and micro scale and extend the application of water-blown polyurethane foams to, e.g., protective covers with zero thermal expansion or even cushions adjustable to a certain body

40 CFR 63.1297 - Standards for slabstock flexible polyurethane foam production-HAP ABA emissions from the...

Science.gov (United States)

2010-07-01

... polyurethane foam production-HAP ABA emissions from the production line. 63.1297 Section 63.1297 Protection of... foam production—HAP ABA emissions from the production line. (a) Each owner or operator of a new or... § 63.1293(a)(1) shall control HAP ABA emissions from the slabstock polyurethane foam production line in...

Properties of polyurethane foam/coconut coir fiber as a core material and as a sandwich composites component

Science.gov (United States)

Azmi, M. A.; Abdullah, H. Z.; Idris, M. I.

2013-12-01

This research focuses on the fabrication and characterization of sandwich composite panels using glass fiber composite skin and polyurethane foam reinforced coconut coir fiber core. The main objectives are to characterize the physical and mechanical properties and to elucidate the effect of coconut coir fibers in polyurethane foam cores and sandwich composite panels. Coconut coir fibers were used as reinforcement in polyurethane foams in which later were applied as the core in sandwich composites ranged from 5 wt% to 20 wt%. The physical and mechanical properties found to be significant at 5 wt% coconut coir fiber in polyurethane foam cores as well as in sandwich composites. It was found that composites properties serve better in sandwich composites construction.

Properties of polyurethane foam/coconut coir fiber as a core material and as a sandwich composites component

International Nuclear Information System (INIS)

Azmi, M A; Abdullah, H Z; Idris, M I

2013-01-01

This research focuses on the fabrication and characterization of sandwich composite panels using glass fiber composite skin and polyurethane foam reinforced coconut coir fiber core. The main objectives are to characterize the physical and mechanical properties and to elucidate the effect of coconut coir fibers in polyurethane foam cores and sandwich composite panels. Coconut coir fibers were used as reinforcement in polyurethane foams in which later were applied as the core in sandwich composites ranged from 5 wt% to 20 wt%. The physical and mechanical properties found to be significant at 5 wt% coconut coir fiber in polyurethane foam cores as well as in sandwich composites. It was found that composites properties serve better in sandwich composites construction

Fabrication of a superhydrophobic polyurethane foam and its application for continuous oil removal

Science.gov (United States)

Liu, Hai-Dong; Gu, Bin; Yuan, Wei-Feng; He, Qi

2018-02-01

A new polyurethane foam with superhydrophobicity and excellent lipophilicity is presented and demonstrated experimentally in this work. The superhydrophobic foam is synthesized by dip coating the polyurethane foam with a mixture solution of silicone resine and silicon dioxide nanoparticles. Its superhydrophobic and oleophilic capacity is characterized and verified via the SEM images, the water contact angle measurement, the adsorption tests and recyclability tests for water and some typical oils. Combining with the vacuum assisted oil-water separation technology (VAST), continuous recovery of oil spill at the lab scale is realized on the new superhydrophobic foam. Moreover, the break through pressure for water penetrating through the superhydrophobic foam is determined experimentally and referred as the maximum operation pressure in the VAST.

Transient Thermal Response of Lightweight Cementitious Composites Made with Polyurethane Foam Waste

Science.gov (United States)

Kismi, M.; Poullain, P.; Mounanga, P.

2012-07-01

The development of low-cost lightweight aggregate (LWA) mortars and concretes presents many advantages, especially in terms of lightness and thermal insulation performances of structures. Low-cost LWA mainly comes from the recovery of vegetal or plastic wastes. This article focuses on the characterization of the thermal conductivity of innovative lightweight cementitious composites made with fine particles of rigid polyurethane (PU) foam waste. Five mortars were prepared with various mass substitution rates of cement with PU-foam particles. Their thermal conductivity was measured with two transient methods: the heating-film method and the hot-disk method. The incorporation of PU-foam particles causes a reduction of up to 18 % of the mortar density, accompanied by a significant improvement of the thermal insulating performance. The effect of segregation on the thermal properties of LWA mortars due to the differences of density among the cementitious matrix, sand, and LWA has also been quantified. The application of the hot-disk method reveals a gradient of thermal conductivity along the thickness of the specimens, which could be explained by a non-uniform repartition of fine PU-foam particles and mineral aggregates within the mortars. The results show a spatial variation of the thermal conductivity of the LWA mortars, ranging from 9 % to 19 %. However, this variation remains close to or even lower than that observed on a normal weight aggregate mortar. Finally, a self-consistent approach is proposed to estimate the thermal conductivity of PU-foam cement-based composites.

Preparation and characterization of new biologically active polyurethane foams.

Science.gov (United States)

Savelyev, Yuri; Veselov, Vitali; Markovskaya, Ludmila; Savelyeva, Olga; Akhranovich, Elena; Galatenko, Natalya; Robota, Ludmila; Travinskaya, Tamara

2014-12-01

Biologically active polyurethane foams are the fast-developed alternative to many applications of biomedical materials. Due to the polyurethane structure features and foam technology it is possible to incorporate into their structure the biologically active compounds of target purpose via structural-chemical modification of macromolecule. A series of new biologically active polyurethane foams (PUFs) was synthesized with polyethers (MM 2500-5000), polyesters MM (500-2200), 2,4(2,6) toluene diisocyanate, water as a foaming agent, catalysts, foam stabilizers and functional compounds. Different functional compounds: 1,4-di-N-oxy-2,3-bis-(oxymethyl)-quinoxaline (DOMQ), partial sodium salt of poly(acrylic acid) and 2,6-dimethyl-N,N-diethyl aminoacetatanilide hydrochloride were incorporated into the polymer structure/composition due to the chemical and/or physical bonding. Structural peculiarities of PUFs were studied by FTIR spectroscopy and X-ray scattering. Self-adhesion properties of PUFs were estimated by measuring of tensile strength at break of adhesive junction. The optical microscopy method was performed for the PUF morphology studies. Toxicological estimation of the PUFs was carried out in vitro and in vivo. The antibacterial action towards the Gram-positive and Gram-negative bacteria (Escherichia coli ATC 25922, E. coli ATC 2150, Klebsiella pneumoniae 6447, Staphylococcus aureus 180, Pseudomonas aeruginosa 8180, Proteus mirabilis F 403, P. mirabilis 6054, and Proteus vulgaris 8718) was studied by the disc method on the solid nutrient. Physic-chemical properties of the PUFs (density, tensile strength and elongation at break, water absorption and vapor permeability) showed that all studied PUFs are within the operational requirements for such materials and represent fine-cellular foams. Spectral studies confirmed the incorporation of DOMQ into the PUF's macrochain. PUFs are characterized by microheterogeneous structure. They are antibacterially active, non

Preconcentration of traces of radionuclides and elements with foamed polyurethane sorbents in the analysis of environmental samples

International Nuclear Information System (INIS)

Palagyi, S.; Braun, T.

1986-01-01

The importance of preconcentration and the permanent need of efficient preconcentrating agents in environmental analysis are pointed out. Foamed polyurethane sorbents draw attention as novel agents in separation chemistry. A survey is presented of recent applications of unloaded and reagent-loaded open-cell type resilient polyurethane foams in the separation and preconcentration of radionuclides from environmental samples, and of the latest uses of these foams in the preconcentration and detection of traces of some, mainly inorganic materials in environmental samples, using radioanalytical techniques. Possible future uses of polyurethane foams in trace element detection in environmental analysis are outlined. (author)

The effect of moisture absorption on the physical properties of polyurethane shape memory polymer foams

International Nuclear Information System (INIS)

Yu, Ya-Jen; Hearon, Keith; Maitland, Duncan J; Wilson, Thomas S

2011-01-01

The effect of moisture absorption on the glass transition temperature (T g ) and the stress/strain behavior of network polyurethane shape memory polymer (SMP) foams has been investigated. With our ultimate goal of engineering polyurethane SMP foams for use in blood-contacting environments, we have investigated the effects of moisture exposure on the physical properties of polyurethane foams. To the best of our knowledge, this study is the first to investigate the effects of moisture absorption at varying humidity levels (non-immersion and immersion) on the physical properties of polyurethane SMP foams. The SMP foams were exposed to differing humidity levels for varying lengths of time, and they exhibited a maximum water uptake of 8.0% (by mass) after exposure to 100% relative humidity for 96 h. Differential scanning calorimetry results demonstrated that water absorption significantly decreased the T g of the foam, with a maximum water uptake shifting the T g from 67 to 5 °C. Samples that were immersed in water for 96 h and immediately subjected to tensile testing exhibited 100% increases in failure strains and 500% decreases in failure stresses; however, in all cases of time and humidity exposure, the plasticization effect was reversible upon placing moisture-saturated samples in 40% humidity environments for 24 h

Auxetic Polyurethane Foam (Fabrication, Properties and Applications)

International Nuclear Information System (INIS)

Yousif, H.I.Y.

2012-01-01

Modern technology requires new materials of special properties. For the last two decades there has been a great interest in a class of materials known as auxetic materials. An auxetic material is a material that has a negative Poisson's ratio which means that this material expands laterally when they subjected to a tensile force unlike most of the other traditional materials. This material has superior properties over the traditional material such as high shear modulus and high impact resistance, which makes this material a good candidate for many engineering applications. In the present research work, auxetic flexible polyurethane polymeric foams having different densities were fabricated from conventional flexible polyurethane polymeric foam at different compression ratios. The microstructure of conventional and processed foams was examined by optical microscope to compare between the two structures. The microstructure of processed foam was compared with the one presented in the literature and it has shown the auxetic structure configuration. This is the first time to produce auxetic foam in Egypt. Conventional and auxetic foam samples having cylindrical and square cross-sections were produced from foams having different densities (25 kg/m 3 and 30 kg/m 3 ). The compression ratios used to produce the auxetic samples are (5.56, 6.94 and 9.26). Four mechanical tests were carried out to get the mechanical properties for both conventional and auxetic foams. Two quasi-static mechanical tests t ension and compression a nd two dynamic mechanical tests H ysteresis and resilience w ere carried out to compare between the conventional and auxetic foams. The quasi-static tensile test was carried out at speed was adjusted to be position control rate of 0.2 mm/s. The compression and hysteresis tests were carried out at strain control rate of 0.3 S -1 . The data recorded from the machine were stress and strain. The modulus of elasticity and Poisson's ratio of the test

Extraction of ruthenium thiocyanate and its separation from rhodium by polyurethane foam

International Nuclear Information System (INIS)

Al-Bazi, S.J.; Chow, A.

1984-01-01

Conditions for the formation and extraction of the thiocyanate complex of ruthenium are reported. Distribution coefficients of more than 10 4 and a capacity of about 0.24 mole per kg of foam were obtained. The effect of the chloride salts of various univalent cations on the extraction of Ru(SCN) 6 3- indicated that the efficiency of ruthenium extraction depends on how well the cation fits into the polyether segment of the polyurethane foam, which agrees with the 'cation-chelation' mechanism. The separation of ruthenium and rhodium indicated that more than 95% of the rhodium remained in the aqueous phase and about 95% of the ruthenium was retained by the polyurethane foam and could be easily recovered. (author)

Synthesis and Characterization of Soy-Based Polyurethane Foam with Utilization of Ethylene Glycol in Polyol

Directory of Open Access Journals (Sweden)

Flora Elvistia Firdaus

2014-08-01

Full Text Available The use of vegetable oils on replacing petroleum has attracted attention of many researchers. The chemical structure of vegetable oils are different from petrochemicals, so the structure of soybean oil has to be chemicallymodified through its unsaturated fatty acid chain in triglyceride. Atwo step process was conducted for the preparationof soy-polyol in designated temperatures; 50 °C, 60 °C, and 70 °C. Ethylene glycol (EG as co-reagent was taking part in soy-polyol synthesis, and the soy-polyol was used as a sole polyol for polyurethane synthesis. Referred to the previous study, the existence of EG in polyurethane synthesis can improved physical properties of polyurethane foam. The aim of this research is using soy-derived polyol for petro-polyol replacement aligned with drop-off of petro-derived reagent; EG. One step process was applied for the foam synthesis.The ingredients for foam synthesis; soy-polyol, Toluene diisocyanate (TDI: a mixture of 2.4 and 2.6 isomers in ratio of 80:20 (TDI T-80, surfactant, and distilled water. The synergize of stoichiometry ratio of co-reagent EG to soy-epoxide with best temperature, with the absence of EG in polyurethane formula can produce an ultimate property of polyurethane foam. 

Separation of cobalt from synthetic intermediate and decontamination radioactive wastes using polyurethane foam

International Nuclear Information System (INIS)

Rao, S.V.S.; Lal, K.B.; Narasimhan, S.V.; Ahmed, J.

1997-01-01

Studies have been carried out on the removal of radioactive cobalt ( 60 Co) from synthetic intermediate level waste (ILW) and decontamination waste using neat polyurethane (PU) foam as well as n-tributyl phosphate-polyurethane (TBP-PU) foam. The radioactive cobalt has been extracted on the PU foam as cobalt thiocyanate from the ILW. Maximum removal of cobalt has been observed when the concentration of thiocyanate in the solution is about 0.4 M. Cobalt can be separated from decontamination waste containing ethylenediaminetetraacetic acid (EDTA) and iron(II). The extent of extraction of cobalt is slow and the separation of iron and cobalt is better with the neat PU foam compared to the TBP-PU foam. The presence of iron in the decontamination waste facilitates the extraction of cobalt thiocyanate on the PU foam. Column studies have been carried out in order to extend these studies to the plant scale. The capacities of the PU foams for cobalt have been determined. The effect of density and the surface area of PU foam have been investigated. Fourier Transform Infrared (FT-IR) spectral studies have been conducted to find out the interaction between PU foam and cobalt thiocyanate species

The use of castor oil polyurethane foam in impact limiters for radioactive materials packages

International Nuclear Information System (INIS)

Mouro, R.P.; Neto, M.M.

2003-01-01

This paper presents ongoing research aiming to assess the use of a 'bio based' polyurethane foam as filling material in impact limiters for transport packages in the nuclear field. The foam is made from castor oil, which replaces the petroleum based polyols in the manufacture of polyurethane products, with good environmental advantages. The research comprises the selection of the cellular material, its structural characterisation by mechanical laboratory tests, the development of a case study, preliminary determination of the best foam density for the case study, performance of the case and its numerical simulation using the finite element method. Prototypes with foam density that is pre-determined as ideal, as well as prototypes using lighter and heavier foams, were tested for comparison. The results obtained validate the research methodology, as expectations about the ideal foam density were confirmed by the drop tests and the numerical simulation. (author)

Effectiveness of Flame Retardants in TufFoam.

Energy Technology Data Exchange (ETDEWEB)

Abelow, Alexis Elizabeth [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Nissen, April [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Massey, Lee Taylor [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Whinnery, LeRoy L. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2017-12-01

An investigation of polyurethane foam filled with known flame retardant fillers including hydroxides, melamine, phosphate-containing compounds, and melamine phosphates was carried out to produce a low-cost material with high flame retardant efficiency. The impact of flame retardant fillers on the physical properties such a s composite foam density, glass transition temperature, storage modulus, and thermal expansion of composite foams was investigated with the goal of synthesizing a robust rigid foam with excellent flame retardant properties.

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

Sorption of Triangular Silver Nanoplates on Polyurethane Foam

Science.gov (United States)

Furletov, A. A.; Apyari, V. V.; Garshev, A. V.; Volkov, P. A.; Tolmacheva, V. V.; Dmitrienko, S. G.

2018-02-01

The sorption of triangular silver nanoplates on polyurethane foam is investigated as a procedure for creating a nanocomposite sensing material for subsequent use in optical means of chemical analysis. Triangular silver nanoplates are synthesized and characterized, and a simple sorption technique for the formation of a composite material based on these nanoplates is proposed.

Polyurethane foam for roadway stabilization NH route 129, Loudon, NH.

Science.gov (United States)

2016-12-12

This report summarizes the evaluation of the performance of polyurethane foam as a method of roadway : stabilization for a rural roadway experiencing substantial frost heaving. : NHDOT is responsible for many roads which have evolved from gravel road...

Utilization of microbial oil obtained from crude glycerol for the production of polyol and its subsequent conversion to polyurethane foams.

Science.gov (United States)

Uprety, Bijaya K; Reddy, Jayanth Venkatarama; Dalli, Sai Swaroop; Rakshit, Sudip K

2017-07-01

We have demonstrated possible use of microbial oil in biopolymer industries. Microbial oil was produced from biodiesel based crude glycerol and subsequently converted into polyol. Fermentation of crude glycerol in a batch bioreactor using Rhodosporidium toruloides ATCC 10788 produced 18.69g/L of lipid at the end of 7days. The microbial oil was then chemically converted to polyol and characterized using FT-IR and 1 H NMR. For comparison, canola oil and palm oil were also converted into their respective polyols. The hydroxyl numbers of polyols from canola, palm and microbial oil were found to be 266.86, 222.32 and 230.30 (mgKOH/g of sample) respectively. All the polyols were further converted into rigid and semi-rigid polyurethanes (maintaining the molar -NCO/-OH ratio of 1.1) to examine their suitability in polymer applications. Conversion of microbial lipid to polyurethane foam also provides a new route for the production of polymers using biodiesel based crude glycerol. Copyright © 2017 Elsevier Ltd. All rights reserved.

Value-added conversion of waste cooking oil and post-consumer PET bottles into biodiesel and polyurethane foams.

Science.gov (United States)

Dang, Yu; Luo, Xiaolan; Wang, Feng; Li, Yebo

2016-06-01

A sustainable process of value-added utilization of wastes including waste cooking oil (WCO) and post-consumer PET bottles for the production of biodiesel and polyurethane (PU) foams was developed. WCO collected from campus cafeteria was firstly converted into biodiesel, which can be used as vehicle fuel. Then crude glycerol (CG), a byproduct of the above biodiesel process, was incorporated into the glycolysis process of post-consumer PET bottles collected from campus to produce polyols. Thirdly, PU foams were synthesized through the reaction of the above produced polyols with isocyanate in the presence of catalysts and other additives. The characterization of the produced biodiesel demonstrated that its properties meet the specification of biodiesel standard. The effect of crude glycerol loading on the properties of polyols and PU foams were investigated. All the polyols showed satisfactory properties for the production of rigid PU foams which had performance comparable to those of some petroleum-based analogs. A mass balance and a cost analysis for the conversion of WCO and waste PET into biodiesel and PU foams were also discussed. This study demonstrated the potential of WCO and PET waste for the production of value-added products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Graded porous polyurethane foam: A potential scaffold for oro-maxillary bone regeneration

Energy Technology Data Exchange (ETDEWEB)

Giannitelli, S.M. [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Basoli, F. [Department of Chemical Science and Technology, University of Rome “Tor Vergata”, Rome (Italy); Mozetic, P. [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Piva, P.; Bartuli, F.N.; Luciani, F. [University of Rome “Tor Vergata”, Rome (Italy); Arcuri, C. [Department of Periodontics, University of Rome “Tor Vergata”, Rome (Italy); U.O.C.C. Odontostomatology, “S. Giovanni Calibita, Fatebenefratelli” Hospital, Rome (Italy); Trombetta, M. [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Rainer, A., E-mail: a.rainer@unicampus.it [Department of Engineering, Tissue Engineering Unit, Università Campus Bio-Medico di Roma, Rome (Italy); Licoccia, S. [Department of Chemical Science and Technology, University of Rome “Tor Vergata”, Rome (Italy)

2015-06-01

Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material—characterized by a dense shell and a porous core—for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cells (hBMSCs). Our findings confirm that the material is potentially suitable for guided bone regeneration applications. - Highlights: • Graded porous polyurethane foams were synthesized via a one-pot foaming reaction. • The inner porous core might act as a scaffold for guided bone regeneration. • A dense outer shell was introduced to act as a barrier to gingival tissue ingrowth. • The synthesized foams were non-toxic and supportive of hBMSC adhesion.

Graded porous polyurethane foam: A potential scaffold for oro-maxillary bone regeneration

International Nuclear Information System (INIS)

Giannitelli, S.M.; Basoli, F.; Mozetic, P.; Piva, P.; Bartuli, F.N.; Luciani, F.; Arcuri, C.; Trombetta, M.; Rainer, A.; Licoccia, S.

2015-01-01

Bone tissue engineering applications demand for biomaterials offering a substrate for cell adhesion, migration, and proliferation, while inferring suitable mechanical properties to the construct. In the present study, polyurethane (PU) foams were synthesized to develop a graded porous material—characterized by a dense shell and a porous core—for the treatment of oro-maxillary bone defects. Foam was synthesized via a one-pot reaction starting from a polyisocyanate and a biocompatible polyester diol, using water as a foaming agent. Different foaming conditions were examined, with the aim of creating a dense/porous functional graded material that would perform at the same time as an osteoconductive scaffold for bone defect regeneration and as a membrane-barrier to gingival tissue ingrowth. The obtained PU was characterized in terms of morphological and mechanical properties. Biocompatibility assessment was performed in combination with bone-marrow-derived human mesenchymal stromal cells (hBMSCs). Our findings confirm that the material is potentially suitable for guided bone regeneration applications. - Highlights: • Graded porous polyurethane foams were synthesized via a one-pot foaming reaction. • The inner porous core might act as a scaffold for guided bone regeneration. • A dense outer shell was introduced to act as a barrier to gingival tissue ingrowth. • The synthesized foams were non-toxic and supportive of hBMSC adhesion

Thermal Properties of Polyurethane-Polyisocyanurate Foams Based on Poly(ethylene terephthalate) Waste

OpenAIRE

Irena VITKAUSKIENĖ; Ričardas MAKUŠKA; Uldis STIRNA; Ugis CABULIS

2011-01-01

A series of polyurethane-polyisocyanurate (PU-PIR) foams synthesized from PET-waste-derived aromatic polyester polyols (APP) was studied using thermogravimetric analysis, Cone calorimeter and burning tests. The effect of chemical structure of the APP containing fragments of glycerol, adipic acid, poly(propylene glycol) or hexanediol on thermal stability and flame resistance of the PU-PIR foams was elucidated. PU-PIR foams prepared from APP containing fragments of glycerol and/or adipic acid h...

Elemental concentrations and bioaccessibilities in beached plastic foam litter, with particular reference to lead in polyurethane.

Science.gov (United States)

Turner, Andrew; Lau, Kwan S

2016-11-15

Seventy samples of foamed plastic collected from a high-energy, sandy beach in SW England have been characterised by FTIR and XRF. Most samples were polyurethane (PU; n=39) or polystyrene (PS; n=27) that were associated with variable concentrations of Br-Cl, Fe and Zn, indicative of the presence of halogenated flame retardants, iron oxides and Zn-based additives, respectively. Many samples of rigid PU contained Pb, historically used as a catalyst, at concentrations of up to 16,000μgg -1 . A physiological extraction test that simulates the conditions in the gizzard of plastic-ingesting seabirds was applied to selected samples and results revealed that while Br and Zn were not measurably bioaccessible, Pb mobilisation progressed logarithmically over a period of time with maximum accessibilities after 220h of ~10% of total metal. Foamed PU is a source of bioaccessible Pb in the marine environment that has not previously been documented. Copyright © 2016 Elsevier Ltd. All rights reserved.

Release of CFC-11 from disposal of polyurethane foam waste

DEFF Research Database (Denmark)

Kjeldsen, Peter; Jensen, M.H.

2001-01-01

The halocarbon CFC-11 has extensively been used as a blowing agent for polyurethane (PUR) insulation foams in home appliances and for residential and industrial construction. Release of CFCs is an important factor in the depletion of the ozone layer. For CFC-11 the future atmospheric concentrations...... will mainly depend on the continued release from PUR foams. Little is known about rates and time frames of the CFC release from foams especially after treatment and disposal of foam containing waste products. The CFC release is mainly controlled by slow diffusion out through the PUR. From the literature...... and by reevaluation of an old reported experiment, diffusion coefficients in the range of 0.05-1.7.10(-14) m(2) s(-1) were found reflecting differences in foam properties and experimental designs. Laboratory experiments studying the distribution of CFC in the foam and the short-term releases after shredding showed...

Recent developments in polyurethane foams containing low-cost and pro-ecological modifiers

OpenAIRE

Kosmela, Paulina; Zedler, Lukasz; Formela, Krzysztof; Haponiuk, Jozef; Piszczyk, Lukasz

2016-01-01

Diversity of the polyurethane (PU) foams applications cause that investigation of the relationships between their structure and properties is currently very popular topic among the many research institutions and companies. At the turn of the last years many scientific papers about PU foams and their composites were published. The one of the main research trends in this field is related to the reduction of production costs of PU foams. This aim can be successfully achieved through the incorpor...

The mechanical behavior of microcellular foams

Energy Technology Data Exchange (ETDEWEB)

Ozkul, M.H.; Mark, J.E. (Cincinnati Univ., OH (USA)); Aubert, J.H. (Sandia National Labs., Albuquerque, NM (USA))

1990-01-01

The mechanical behavior of microcellular open-cell foams prepared by a thermally induced phase separation process are investigated. The foams studied were prepared from isotactic polystyrene, polyacrylonitrile, and poly(4-methyl-1-pentene) (rigid foams), and polyurethane and Lycra (elastomeric foams). Their densities were in the range 0.04--0.27 g/cm3. Conventional polystyrene foams were used for comparison. The moduli and collapse stresses of these foams were measured in compression and compared with the current constitutive laws which relate mechanical properties to densities. A reinforcement technique based on the in-situ precipitation of silica was used to improve the mechanical properties. 13 refs., 4 figs., 3 tabs.

MALDI-TOF and 13C NMR Analysis of Tannin–Furanic–Polyurethane Foams Adapted for Industrial Continuous Lines Application

Directory of Open Access Journals (Sweden)

Maria Cecilia Basso

2014-12-01

Full Text Available Mixed phenolic-polyurethane-type rigid foams were developed using tannin-furfuryl alcohol natural materials co-reacted with polymeric isocyanate in the proportions imposed by the limitations inherent to continuous industrial plants for polyurethane foams. A variety of different copolymerization oligomers formed. Urethanes appeared to have been formed with two flavonoid tannin sites, mainly at the flavonoid hydroxyl group at C3, but also, although less, on the phenolic hydroxyl groups of the flavonoid oligomers. Urethanes are also formed with (i glyoxal in the formulation, be it pre-reacted or not with the tannin; (ii with phenolsulfonic acid and (iii with furfural. This latter one, however, greatly favors reaction with the A-ring of the flavonoids through a methylene bridge rather than reaction with the isocyanate groups to form urethanes. All of the materials appeared to have co-reacted in a manner to form urethane and methylene bridges between all of the main components used. Thus, the tannin, the furfuryl alcohol, the isocyanate, the glyoxal and even the phenol sulfonic acid hardener formed a number of mixed species linked by the two bridge types. Several mixed species comprised of 2, 3 and even 4 co-reacted different components have been observed.

Sanitary and hygienic assessment of polyurethane foam compositions

Energy Technology Data Exchange (ETDEWEB)

Sukhanov, V V; Putilina, O.N. (Donetskii NII Gigieny Truda i Professional' nykh Zabolevanii (USSR))

1990-07-01

Describes and presents the results of a long-term study performed by the Skochinski Institute and DonUGI into the suitability of various Soviet and foreign polyurethane foams as rock strengtheners in coal mines. Concludes that although further research is needed to clarify the effect of polyurethane absorbed by coal particles and on pneumoconioses, the industrial use of injectable polyisocyanite-based polyurethanes in amounts of up to 1 t/shift and with a minimum air exchange rate of 300 m{sup 3}/min is feasible as long as the safety laws are strictly observed. Those working with this material should be given a medical examination at least once a year. If the substance comes into contact with the skin or eyes, they should be washed with a 1-3% solution of sodium bicarbonate and then pure water; if it contaminates protective clothing this should be degassed in a 5-10% solution of ammonia for 24 hours and then washed. Due to the risk of toxic substances being released from the components of the polyurethane in the event of an endogenic fire, all workers should be equipped with their own personal breathing apparatus.

Extraction of Mo, W and Tc with polyurethane foam and with cyclic polyether from SCN-/HC1 medium

International Nuclear Information System (INIS)

Caletka, R.; Hausbeck, R.; Krivan, V.

1986-01-01

The extraction of molybdenum, tungsten and technetium by polyether-based polyurethane foam and by a cyclic polyether from aqueous thiocyanate solutions is described. The influence of the reductants stannous chloride and ascorbic acid has also been studied. The possibilites of the polyurethane foam for preconcentration and determination of molybdenum are discussed. (author)

PUR-PIR foam produced based on poly(hydroxybutyl citrate foamed founded with different factories

Directory of Open Access Journals (Sweden)

Liszkowska Joanna

2018-03-01

Full Text Available A poly(hydroxybutyl citrate p(HBC was obtained. The product compound produced in the solution during esterification, was added to rigid polyurethane-polyisocyanurate foams (PUR-PIR. The amount of petrochemical polyol in the foams was decreased in favor of the p(HBC from 0.1 to 0.5 equivalent. The foams were foamed in two ways: with distilled water (W foams and with Solkane 365/227 (S foams. The examination results of both foam series were compared. They showed that the foams foamed with water have higher softening temperature than the foams foamed with solkane. The retention values for both foam series are around 91–95%, and water absorption in the range of 0.7–3.2%. The anisotropy coefficient did not exceed 1.08 (the lowest value being 1.01.

MICROCT AND PREPARATION OF ß-TCP GRANULAR MATERIAL BY THE POLYURETHANE FOAM METHOD

Directory of Open Access Journals (Sweden)

Robert Filmon

2011-05-01

Full Text Available Commercial ß-tricalcium phosphate (ß-TCP is commercialy available in granules manufactured by sintering of powders. We have evaluated the different steps of the manufacturing process of ß-TCP ceramics granules prepared from blocks obtained with the polyurethane foam technology. Three types of slurry were prepared with 10, 15 and 25 g of ß-TCP per gram of polyurethane foam. Analysis was done by scanning electron microscopy, EDX, Raman spectroscopy and microcomputed tomography combined with image analysis. A special algorithm was used to identify the internal microporosity (created by the calcination of the foam from the internal macroporosity due to the spatial repartition of the material. The low ß-TCP dosages readily infiltrated the foam and the slurry was deposited along the polymer rods. On the contrary, the highest concentration produced inhomogeneous infiltrated blocks and foam cavities appeared completely filled in some areas. 2D microcomputed sections and reconstructed 3D models evidenced this phenomenon and the frequency distribution of the thickness and separation of material trabeculae confirmed the heterogeneity of the distribution. When crushed, blocks prepared with the 25 g slurry provided the largest and irregular granulates.

Fabrication of antibacterial water filter by coating silver nanoparticles on flexible polyurethane foams

International Nuclear Information System (INIS)

Nguyen Thi Phuong Phong; Ngo Vo Ke Thanh; Phan Hue Phuong

2009-01-01

In this paper, we fabricated silver-coated polyurethane foams and used it as a bacterial filter for contaminated drinking water. Flexible PU foams were soaked in silver colloidal solutions for 10 h, then washed and air-dried at room temperature. The prepared silver colloidal solutions and silver-coated PU materials were characterized by several techniques including TEM, FESEM/EDS, UV-VIS, ICP-AAS, and Raman spectroscopy. The TEM images showed that the size of silver nanoparticles in colloidal solutions varies from 6 to 12nm. The Raman, FE-SEM/EDS and ICP-AAS data illustrated that silver nanoparticles were stable on the PU foam and were not washed away by water. Furthermore, the microbiological tests (tube tests and flow test) were carried out on silver-coated PU materials with the Coliforms, E. coli, and B. subtilis. The obtained results showed that the bacteria was killed completely with antibacterial efficiency of 100% being observed. Our research suggests that silver-coated polyurethane foams can be used as excellent antibacterial water filters and would have several applications in other sectors.

Thermal properties of a sandwich construction insulated with Polyurethane (DC-System)

DEFF Research Database (Denmark)

Jensen, Rasmus Lund; Dreau, Jerome Le

Rigid polyurethane foam (PUR) is a good thermal insulation product for buildings, mainly due to its low thermal conductivity (λ ≈ 20 mW/m.K), low permeability to water and stability over time. The other types of insulation products available on the market have a significantly higher thermal...... conductivity: + 50% for expanded polystyrene (λ ≈ 30 mW/m.K), + 75% for mineral wools (λ ≈ 35 mW/m.K), etc. Despite its low thermal conductivity, polyurethane foam (PUR) is not much used as insulation material for walls because of its low resistance to fire. The most common PUR boards are classified C-s2-d0...

Unloaded polyether type polyurethane foams as solid extractants for trace elements

International Nuclear Information System (INIS)

Palagyi, S.; Braun, T.

1992-01-01

Polyether type polyurethane foams (PU) are regular stacks of solid quasi-spherical membranes produced by the reaction of polyisocyanates with polyols of polyether nature in the presence of a catalyst and a blowing agent. Contrary to conventional membrane separations, where a solid membrane is merely a differentially separating agent, or a transport medium, PU foams, apart from separation and preconcentration, also retain, i.e., sorb the species on, or in the membranes. Therefore, PU foam membranes can be considered to act as true sorbents. The membrane properties of PU foam sorbents offer unique advantages over conventional bulk type granular sorbents in rapid, versatile and effective separations and preconcentrations of different compounds from fluid samples. Unloaded PU foam sorbents have received considerable attention in the separation of different trace inorganic species. (author) 74 refs.; 1 fig.; 1 tab

Polyurethane foams based entirely on recycled polyols derived from natural oils

Czech Academy of Sciences Publication Activity Database

Horák, Pavel; Beneš, Hynek

2015-01-01

Roč. 60, č. 9 (2015), s. 579-585 ISSN 0032-2725 R&D Projects: GA MPO(CZ) FR-TI4/133 Institutional support: RVO:61389013 Keywords : polyurethane foam * recycled polyol * rapeseed oil Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.718, year: 2015

Studies on incorporation of exfoliated bentonitic clays in polyurethane foams for increasing flame retardancy

International Nuclear Information System (INIS)

Quagliano, J; García, Irma Gavilán

2012-01-01

In this contribution we report the results of studying the incorporation of exfoliated bentonitic clays into polyurethane foams. A suspension in water of a sodium bentonite from Argentine Patagonia was interchanged with cetyl trimethyl ammonium bromide (CTAB) for 4 h at 80°C, rendering an exfoliated clay, which is nanometric in only one dimension. This nanoclay, when dispersed in the polyurethane, resulted in the same fire retardancy rating (UL-94) than when polyurethane was treated with a commercial nanoclay. Scanning electron microscopy (SEM) at low augmentations of polyurethane samples treated with the synthethized nanoclay (2,5% w/w) showed no differences respect to untreated polyurethane, except for the irregularity of void edges.

Emission of volatiles from spray polyurethane foam (SPF) insulated crawl spaces

NARCIS (Netherlands)

Havermans, J.B.G.A.

2014-01-01

The emission of (di)isocyantes, polyols and blowing agents from curing Spray Polyurethane Foam (SPF) was studied in a house having its crawl space recently insulated. Before insulation a blank measurement was made and he emission was followed up to 144 hours after the insolation application. The

Compressibility and phase contrast imaging of a irradiated polyurethane foam blocks

International Nuclear Information System (INIS)

Naik, Y.; Kulkarni, S.G.; Manjunath, B.S.; Patel, R.J.; Agarwal, A.K.; Kashyap, Y.; Sinha, A.

2013-01-01

Polyurethane foam was prepared with a view to use them as a protective enclosure for radioactive material transport package against accidental mechanical shock and fire. The foam samples were prepared by mixing the polyol premixed with additives such as water as blowing agent, melamine polyphosphate as a flame retardants (FR) and catalyst with isocynate keeping NCO/OH ratio as 1.1. It was observed that the irradiation of the foam results in cross linking leading to increased wall thickness and shrinkage of cellular structure. This leads to increased strain around the foam bubble. Increased exposure to gamma rays to higher doses results in reptures at the cellular boundary connecting the bubble structure, leading to decreased mechanical strength. This leads again to increase in deformation seen in the 15 and 20 kGy irradiated samples

Green engineering: Green composite material, biodiesel from waste coffee grounds, and polyurethane bio-foam

Science.gov (United States)

Cheng, Hsiang-Fu

In this thesis we developed several ways of producing green materials and energy resources. First, we developed a method to fabricate natural fibers composites, with the purpose to develop green textile/woven composites that could potentially serve as an alternative to materials derived from non-renewable sources. Flax and hemp fabrics were chosen because of their lightweight and exceptional mechanical properties. To make these textile/woven composites withstand moist environments, a commercially available marine resin was utilized as a matrix. The tensile, three-point bending, and edgewise compression strengths of these green textile/woven composites were measured using ASTM protocols. Secondly, we developed a chemical procedure to obtain oil from waste coffee grounds; we did leaching and liquid extractions to get liquid oil from the solid coffee. This coffee oil was used to produce bio-diesel that could be used as a substitute for petroleum-based diesel. Finally, polyurethane Bio-foam formation utilized glycerol that is the by-product from the biodiesel synthesis. A chemical synthesis procedure from the literature was used as the reference system: a triol and isocynate are mixed to produce polyurethane foam. Moreover, we use a similar triol, a by-product from bio-diesel synthesis, to reproduce polyurethane foam.

Glycolysis of flexible polyurethane foam in recycling of car seats

Czech Academy of Sciences Publication Activity Database

Beneš, Hynek; Rösner, J.; Holler, Petr; Synková, Hana; Kotek, Jiří; Horák, Zdeněk

2007-01-01

Roč. 18, č. 2 (2007), s. 149-156 ISSN 1042-7147. [International Conference on Polymeric Materials in Automotive , Slovak Rubber Conference /17./. Bratislava, 10.5.2005-12.5.2005] R&D Projects: GA MŽP SL/7/26/05 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyurethanes * foams * recycling Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.504, year: 2007

Inhibition of Microbial Growth by Fatty Amine Catalysts from Polyurethane Foam Test Tube Plugs

Science.gov (United States)

Bach, John A.; Wnuk, Richard J.; Martin, Delano G.

1975-01-01

When polyurethane foam test tube plugs are autoclaved, they release volatile fatty amines that inhibit the growth of some microorganisms. The chemical structures of these amines were determined by the use of a gas chromatographmass spectrometer. They are catalysts used to produce the foam. The problem of contaminating growth media with toxic substances released from polymeric materials is discussed. PMID:1096816

Method for providing a low density high strength polyurethane foam

Science.gov (United States)

Whinnery, Jr., Leroy L.; Goods, Steven H.; Skala, Dawn M.; Henderson, Craig C.; Keifer, Patrick N.

2013-06-18

Disclosed is a method for making a polyurethane closed-cell foam material exhibiting a bulk density below 4 lbs/ft.sup.3 and high strength. The present embodiment uses the reaction product of a modified MDI and a sucrose/glycerine based polyether polyol resin wherein a small measured quantity of the polyol resin is "pre-reacted" with a larger quantity of the isocyanate in a defined ratio such that when the necessary remaining quantity of the polyol resin is added to the "pre-reacted" resin together with a tertiary amine catalyst and water as a blowing agent, the polymerization proceeds slowly enough to provide a stable foam body.

Application of Multi-Layered Polyurethane Foams for Flat-Walled Anechoic Linings

DEFF Research Database (Denmark)

Xu, J. F.; Buchholz, Jörg; Fricke, Fergus R.

2006-01-01

of the application of multi-layered polyurethane foams as the flat-walled anechoic lining. The investigation includes aspects such as the efficacy of a single layer of material, the minimum number of layers of linings to achieve the minimum overall thickness for low (100Hz), mid (250Hz) and high (500Hz) cut...

40 CFR 63.1298 - Standards for slabstock flexible polyurethane foam production-HAP emissions from equipment cleaning.

Science.gov (United States)

2010-07-01

... polyurethane foam production-HAP emissions from equipment cleaning. 63.1298 Section 63.1298 Protection of... foam production—HAP emissions from equipment cleaning. Each owner or operator of a new or existing...(a)(1) shall not use a HAP or a HAP-based material as an equipment cleaner. ...

A phenomenological constitutive model for low density polyurethane foams

International Nuclear Information System (INIS)

Neilsen, M.K.; Morgan, H.S.; Krieg, R.D.

1987-04-01

Results from a series of hydrostatic and triaxial compression tests which were performed on polyurethane foams are presented in this report. These tests indicate that the volumetric and deviatoric parts of the foam behavior are strongly coupled. This coupling behavior could not be captured with any of several commonly used plasticity models. Thus, a new constitutive model was developed. This new model was based on a decomposition of the foam response into two parts: (1) response of the polymer skeleton, and (2) response of the air inside the cells. The air contribution was completely volumetric. The new constitutive model was implemented in two finite element codes, SANCHO and PRONTO. Results from a series of analyses completed with these codes indicated that the new constitutive model captured all of the foam behaviors that had been observed in the experiments. Finally, a typical dynamic problem was analyzed using the new constitutive model and other constitutive models to demonstrate differences between the models. Results from this series of analyses indicated that the new constitutive model generated displacement and acceleration predictions that were between predictions obtained using the other models. This result was expected. 9 refs., 45 figs., 4 tabs

Development of test systems for characterizing emissions from spray polyurethane foam insulation (SPFI)

Science.gov (United States)

The relationship between onsite manufacture of spray polyurethane foam insulation (SPFI) and potential exposures to diisocyanates, amines, flame retardants (FRs), blowing agents, aldehydes and other organic compounds that may be emitted from SPFI is not well understood. EPA is de...

Preconcentration and determination of uranium on to polyurethane foam functionalized with salicylate

International Nuclear Information System (INIS)

Sousa, Alvaro S.F. de; Ferreira, Elizabeth de M.M.; Cassella, Ricardo J.

2009-01-01

Salicylate was covalently linking with a commercial polyurethane foam (PUF) through -N=N-group generating a stable chelating sorbent (PUFS). The synthesized sorbent was characterized by Infrared Spectrometry (IR) measurement. Good stability towards various solvents was noticed. The pH influence and equilibration shaking time adsorption onto foam functionalized was studied as factors influencing the extraction process of the uranium ion solution. Extraction of uranium was accomplished in 10 minutes. Uranium at ppb level was absorbed as the salicylate complex on powered PUFS at pH about 8.0. Uranium could be achieved in 85 % from a 500 mL uranium solution (0.1 μgmL -1 ) which shows the suitability of salicylate foam for preconcentration analysis. (author)

Modeling Manufacturing Impacts on Aging and Reliability of Polyurethane Foams

Energy Technology Data Exchange (ETDEWEB)

Rao, Rekha R.; Roberts, Christine Cardinal; Mondy, Lisa Ann; Soehnel, Melissa Marie; Johnson, Kyle; Lorenzo, Henry T.

2016-10-01

Polyurethane is a complex multiphase material that evolves from a viscous liquid to a system of percolating bubbles, which are created via a CO2 generating reaction. The continuous phase polymerizes to a solid during the foaming process generating heat. Foams introduced into a mold increase their volume up to tenfold, and the dynamics of the expansion process may lead to voids and will produce gradients in density and degree of polymerization. These inhomogeneities can lead to structural stability issues upon aging. For instance, structural components in weapon systems have been shown to change shape as they age depending on their molding history, which can threaten critical tolerances. The purpose of this project is to develop a Cradle-to-Grave multiphysics model, which allows us to predict the material properties of foam from its birth through aging in the stockpile, where its dimensional stability is important.

Bio-based polyurethane foams toward applications beyond thermal insulation

International Nuclear Information System (INIS)

Gama, Nuno V.; Soares, Belinda; Freire, Carmen S.R.; Silva, Rui; Neto, Carlos P.; Barros-Timmons, Ana; Ferreira, Artur

2015-01-01

Highlights: • Coffee grounds wastes were successfully liquefied yielding a bio-based polyol. • Coffee grounds derived foams formulations were optimized by tuning reagents’ contents. • The viscoelastic properties of these foams are promising to expand their applications. - Abstract: In this work the preparation of viscoelastic bio-based polyurethane foams (PUFs) using polyols obtained via acid liquefaction of coffee grounds wastes has been optimized. In a first stage, the effect of different ratios of isocyanate content to hydroxyl number (0.6, 0.7 and 0.8) and of three distinct percentages of catalyst (3%, 5% and 7%) on the extent of the polymerization reaction was studied by infrared spectroscopy. Next, different percentages of surfactant (14%, 16% and 18%) and blowing agent (12%, 14% and 16%) were used to assess their effect on the density, thermal conductivity and mechanical properties of the foams, including their recovery time. The mechanical properties of the ensuing foams proved to be very interesting due to their viscoelastic behavior. PUFs were also characterized by scanning electron microscopy (SEM) revealing a typical cellular structure and by thermogravimetric analysis (TGA) which proved that these materials are thermally stable up to 190 °C. These results suggest other potential applications for these materials beyond heat insulation in areas where damping properties can be an added value

Rigid polyurethane foam (RPF) technology for Countermine (Sea) Program -- Phase 1

Energy Technology Data Exchange (ETDEWEB)

Woodfin, R.L. [Sandia National Labs., Albuquerque, NM (United States). Exploratory Sensors and Munitions Dept.

1997-01-01

This Phase 1 report documents the results of one of the subtasks that was initiated under the joint Department of Energy (DOE)/Department of Defense (DoD) Memorandum of Understanding (MOU) for Countermine Warfare. The development of a foam that can neutralize mines and barriers and allow the safe passage of amphibious landing craft and vehicles was the objective of this subtask of the Sea Mine Countermeasures Technology program. This phase of the program concentrated on laboratory characterization of foam properties and field experiments with prefabricated foam blocks to determine the capability of RPF to adequately carry military traffic. It also established the flammability characteristics of the material under simulated operational conditions, extended the understanding of explosive cavity formation in RPF to include surface explosions, established the tolerance to typical military fluids, and the response to bullet impact. Many of the basic analyses required to establish the operational concept are reported. The initial field experiments were conducted at the Energetic Materials Research and Testing Center (EMRTC) of the New Mexico Institute of Mining and Technology, Socorro, NM in November 1995 through February 1996.

Thermal Properties of Polyurethane-Polyisocyanurate Foams Based on Poly(ethylene terephthalate Waste

Directory of Open Access Journals (Sweden)

Irena VITKAUSKIENĖ

2011-09-01

Full Text Available A series of polyurethane-polyisocyanurate (PU-PIR foams synthesized from PET-waste-derived aromatic polyester polyols (APP was studied using thermogravimetric analysis, Cone calorimeter and burning tests. The effect of chemical structure of the APP containing fragments of glycerol, adipic acid, poly(propylene glycol or hexanediol on thermal stability and flame resistance of the PU-PIR foams was elucidated. PU-PIR foams prepared from APP containing fragments of glycerol and/or adipic acid had higher thermal stability and lower weight loss at 330 °C. The foams based on APP derived from industrial PET waste were characterized by relatively low heat release and low smoke production. The presence of the fragments of the functional additives glycerol and/or adipic acid in the structure of APP used for production of PU-PIR foams, marginally decreased the heat release and slightly increased the smoke production.http://dx.doi.org/10.5755/j01.ms.17.3.588

Inflatable Tubular Structures Rigidized with Foams

Science.gov (United States)

Tinker, Michael L.; Schnell, Andrew R.

2010-01-01

Inflatable tubular structures that have annular cross sections rigidized with foams, and the means of erecting such structures in the field, are undergoing development. Although the development effort has focused on lightweight structural booms to be transported in compact form and deployed in outer space, the principles of design and fabrication are also potentially applicable to terrestrial structures, including components of ultralightweight aircraft, lightweight storage buildings and shelters, lightweight insulation, and sales displays. The use of foams to deploy and harden inflatable structures was first proposed as early as the 1960s, and has been investigated in recent years by NASA, the U.S. Air Force Research Laboratory, industry, and academia. In cases of deployable booms, most of the investigation in recent years has focused on solid cross sections, because they can be constructed relatively easily. However, solid-section foam-filled booms can be much too heavy for some applications. In contrast, booms with annular cross sections according to the present innovation can be tailored to obtain desired combinations of stiffness and weight through choice of diameters, wall thicknesses, and foam densities. By far the most compelling advantage afforded by this innovation is the possibility of drastically reducing weights while retaining or increasing the stiffnesses, relative to comparable booms that have solid foamfilled cross sections. A typical boom according to this innovation includes inner and outer polyimide film sleeves to contain foam that is injected between them during deployment.

The effects of using immobilizer made of the polyurethane foam

International Nuclear Information System (INIS)

Kim, Yong Hwan; Chung, Sang Hwa; Kim, Hwa Young; Lim, Shin Taek; Oh, Sae Dong

1992-01-01

The immogilzer for control the patient movement during the radiation beam on was made of the polyurethane foam. The time consumption is abut 8 minutes for completely making the immobilizer. In this experimental study, the effects of using the individual immobilizer have shown that the patients have had always a same position with comfortable and high reproducibilities. Furthermore, it has shown the time for patient setup was decreased by using the individual patient immobilizer.

PUFoam : A novel open-source CFD solver for the simulation of polyurethane foams

Science.gov (United States)

Karimi, M.; Droghetti, H.; Marchisio, D. L.

2017-08-01

In this work a transient three-dimensional mathematical model is formulated and validated for the simulation of polyurethane (PU) foams. The model is based on computational fluid dynamics (CFD) and is coupled with a population balance equation (PBE) to describe the evolution of the gas bubbles/cells within the PU foam. The front face of the expanding foam is monitored on the basis of the volume-of-fluid (VOF) method using a compressible solver available in OpenFOAM version 3.0.1. The solver is additionally supplemented to include the PBE, solved with the quadrature method of moments (QMOM), the polymerization kinetics, an adequate rheological model and a simple model for the foam thermal conductivity. The new solver is labelled as PUFoam and is, for the first time in this work, validated for 12 different mixing-cup experiments. Comparison of the time evolution of the predicted and experimentally measured density and temperature of the PU foam shows the potentials and limitations of the approach.

Development of rubidium and niobium containing plastic foams. Final report

International Nuclear Information System (INIS)

Botham, R.A.; McClung, C.E.; Schwendeman, J.I.

1978-01-01

Rubidium fluoride and niobium metal-containing foam samples (rods and sheets) were prepared using two foam sytems: (1) hydrophilic polyurethanes prepared from W.R. Grace Co.'s Hypol prepolymers and (2) polyimides prepared from Monsanto Company's Skybond polyimide resin. The first system was used only for preparation of rubidium fluoride-containing foams while the second was used for both rubidium fluoride and niobium-containing foams. The niobium metal could readily be incorporated into the polyimide foam during molding, to produce foam sheets of the required dimensions and density. The rubidium fluoride-containing polyimide foams were preferably prepared by first rendering the molded polyimide foam hydrophilic with a postcuring treatment, then absorbing the rubidium fluoride from water solution. Similarly, rubidium fluoride was absorbed into the hydrophilic polyurethanes from water solution. Since the high reactive rubidium metal could not be employed, rubidium fluoride, which is very hygroscopic, was used instead, primarily because of its high rubidium content (approximately 82 weight percent). This was important in view of the low total densities and the high weight percentage rubidium required in the foam samples. In addition, at the later request of LLL, a block of rigid Hypol hydrophilic polyurethane foam (with a density of approximately 0.04 g/cm 3 and cell sizes = or <0.2 mm) was prepared without any metal or metal compounds in it. Two shipments of foam samples, which met or closely approximated the project specifications, were submitted to LLL during the course of this project. Information on these samples is contained in Table 1. A complete description of their preparation is given in the Experimental Results and Discussion Section

Validation of Heat Transfer Thermal Decomposition and Container Pressurization of Polyurethane Foam.

Energy Technology Data Exchange (ETDEWEB)

Scott, Sarah Nicole; Dodd, Amanda B.; Larsen, Marvin E.; Suo-Anttila, Jill M.; Erickson, Kenneth L

2014-09-01

Polymer foam encapsulants provide mechanical, electrical, and thermal isolation in engineered systems. In fire environments, gas pressure from thermal decomposition of polymers can cause mechanical failure of sealed systems. In this work, a detailed uncertainty quantification study of PMDI-based polyurethane foam is presented to assess the validity of the computational model. Both experimental measurement uncertainty and model prediction uncertainty are examined and compared. Both the mean value method and Latin hypercube sampling approach are used to propagate the uncertainty through the model. In addition to comparing computational and experimental results, the importance of each input parameter on the simulation result is also investigated. These results show that further development in the physics model of the foam and appropriate associated material testing are necessary to improve model accuracy.

A finite element/level set model of polyurethane foam expansion and polymerization

Energy Technology Data Exchange (ETDEWEB)

Rao, Rekha R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Long, Kevin Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Christine Cardinal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brunini, Victor [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soehnel, Melissa Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Noble, David R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tinsley, James [Honeywell Federal Manufacturing & Technologies, Kansas City, MO (United States); Mondy, Lisa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-12-01

Polyurethane foams are used widely for encapsulation and structural purposes because they are inexpensive, straightforward to process, amenable to a wide range of density variations (1 lb/ft3 - 50 lb/ft3), and able to fill complex molds quickly and effectively. Computational model of the filling and curing process are needed to reduce defects such as voids, out-of-specification density, density gradients, foam decomposition from high temperatures due to exotherms, and incomplete filling. This paper details the development of a computational fluid dynamics model of a moderate density PMDI structural foam, PMDI-10. PMDI is an isocyanate-based polyurethane foam, which is chemically blown with water. The polyol reacts with isocyanate to produces the polymer. PMDI- 10 is catalyzed giving it a short pot life: it foams and polymerizes to a solid within 5 minutes during normal processing. To achieve a higher density, the foam is over-packed to twice or more of its free rise density of 10 lb/ft3. The goal for modeling is to represent the expansion, filling of molds, and the polymerization of the foam. This will be used to reduce defects, optimize the mold design, troubleshoot the processed, and predict the final foam properties. A homogenized continuum model foaming and curing was developed based on reaction kinetics, documented in a recent paper; it uses a simplified mathematical formalism that decouples these two reactions. The chemo-rheology of PMDI is measured experimentally and fit to a generalized- Newtonian viscosity model that is dependent on the extent of cure, gas fraction, and temperature. The conservation equations, including the equations of motion, an energy balance, and three rate equations are solved via a stabilized finite element method. The equations are combined with a level set method to determine the location of the foam-gas interface as it evolves to fill the mold. Understanding the thermal history and loads on the foam due to exothermicity and oven

Cryogenic Moisture Uptake in Foam Insulation for Space Launch Vehicles

Science.gov (United States)

Fesmire, James E.; ScholtensCoffman, Brekke E.; Sass, Jared P.; Williams, Martha K.; Smith, Trent M.; Meneghelli, Barrry J.

2008-01-01

Rigid polyurethane foams and rigid polyisocyanurate foams (spray-on foam insulation), like those flown on Shuttle, Delta IV, and will be flown on Ares-I and Ares-V, can gain an extraordinary amount of water when under cryogenic conditions for several hours. These foams, when exposed for eight hours to launch pad environments on one side and cryogenic temperature on the other, increase their weight from 35 to 80 percent depending on the duration of weathering or aging. This effect translates into several thousand pounds of additional weight for space vehicles at lift-off. A new cryogenic moisture uptake apparatus was designed to determine the amount of water/ice taken into the specimen under actual-use propellant loading conditions. This experimental study included the measurement of the amount of moisture uptake within different foam materials. Results of testing using both aged specimens and weathered specimens are presented. To better understand cryogenic foam insulation performance, cryogenic moisture testing is shown to be essential. The implications for future launch vehicle thermal protection system design and flight performance are discussed.

Use of open-cell resilient polyurethane foam loaded with crown ether for the preconcentration of uranium from aqueous solutions

International Nuclear Information System (INIS)

Abou-Mesalam, M.M.; El-Naggar, I.M.; Abdel-Hai, M.S.; El-Shahawi, M.S.

2003-01-01

The preconcentration of uranium from aqueous solutions on open-cell resilient polyurethane foams (PUF) impregnated with crown ether as an organic extractant in different conditions was investigated. The data showed that 50 minutes is a sufficient time to attain equilibrium with a maximum extraction percentage for uranium ion on polyurethane foams loaded with crown ether. Also the extraction percentage of uranium is increased markedly with increasing the pH values up to pH ∼ 6 and displayed the lowest extraction at 8 > pH > 6. The different isotherms of uranium sorption have shown that the sorption followed a Freundlich isotherm. Column studies have been carried out in order to extend these studies to the plant scale. From the data of column sorption and breakthrough curves, the height equivalent of theoretical plates (HETP), and breakthrough capacity which affect the efficiency of the column have been calculated and found to be 1.03 mm/plate, 64 ± 5 and 58.3 mg uranium/gram polyurethane foam impregnated with crown ether, respectively. (author)

Modeling of Flexible Polyurethane Foam Shrinkage for Bra Cup Moulding Process Control

Directory of Open Access Journals (Sweden)

Long Wu

2018-04-01

Full Text Available Nowadays, moulding technology has become a remarkable manufacturing process in the intimate apparel industry. Polyurethane (PU foam sheets are used to mould three-dimensional (3D seamless bra cups of various softness and shapes, which eliminate bulky seams and reduce production costs. However, it has been challenging to accurately and effectively control the moulding process and bra cup thickness. In this study, the theoretical mechanism of heat transfer and the thermal conductivity of PU foams are first examined. Experimental studies are carried out to investigate the changes in foam materials at various moulding conditions (viz., temperatures, and lengths of dwell time in terms of surface morphology and thickness by using electron and optical microscopy. Based on the theoretical and experimental investigations of the thermal conductivity of the foam materials, empirical equations of shrinkage ratio and thermal conduction of foam materials were established. A regression model to predict flexible PU foam shrinkage during the bra cup moulding process was formulated by using the Levenberg-Marquardt method of nonlinear least squares algorithm and verified for accuracy. This study therefore provides an effective approach that optimizes control of the bra cup moulding process and assures the ultimate quality and thickness of moulded foam cups.

Copper ferrocyanide - polyurethane foam as a composite ion exchanger for removal of radioactive cesium

International Nuclear Information System (INIS)

Rao, S.V.S.; Lal, K.B.; Ahmed, J.; Narasimhan, S.V.

1999-01-01

A method has been developed for the removal of cesium from the aqueous radioactive waste using a composite ion-exchanger consisting of Copper-Ferrocyanide Powder (CFC) and Polyurethane (PU) Foam. Polyvinyl acetate has been used as a binder in the preparation of CFC-PU foam. The physical properties of CFC such as density, surface area, IR stretching frequency and lattice parameters have been evaluated and also its potassium and copper(II) content have been estimated. Optimization of loading of CFC on PU foam has been studied. The CFC-PU was viewed under microscope to find out the homogeneity of distribution. Exchange capacities of the CFC-PU foam in different media have been determined and column studies have been carried out. Studies have been undertaken on extraction of cesium from CFC foam and also on digestion of spent CFC-PU foam and immobilization of digested solution in cement matrix. The cement matrices have been characterized with respect to density, bio-resistance and leaching resistance. (author)

Experiments to populate and validate a processing model for polyurethane foam. BKC 44306 PMDI-10

Energy Technology Data Exchange (ETDEWEB)

Mondy, Lisa Ann [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rao, Rekha Ranjana [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shelden, Bion [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soehnel, Melissa Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); O' Hern, Timothy J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grillet, Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wyatt, Nicholas B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Russick, Edward Mark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hileman, Michael Bryan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Urquhart, Alexander [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Thompson, Kyle Richard [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Smith, David Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2014-03-01

We are developing computational models to elucidate the expansion and dynamic filling process of a polyurethane foam, PMDI. The polyurethane of interest is chemically blown, where carbon dioxide is produced via the reaction of water, the blowing agent, and isocyanate. The isocyanate also reacts with polyol in a competing reaction, which produces the polymer. Here we detail the experiments needed to populate a processing model and provide parameters for the model based on these experiments. The model entails solving the conservation equations, including the equations of motion, an energy balance, and two rate equations for the polymerization and foaming reactions, following a simplified mathematical formalism that decouples these two reactions. Parameters for the polymerization kinetics model are reported based on infrared spectrophotometry. Parameters describing the gas generating reaction are reported based on measurements of volume, temperature and pressure evolution with time. A foam rheology model is proposed and parameters determined through steady-shear and oscillatory tests. Heat of reaction and heat capacity are determined through differential scanning calorimetry. Thermal conductivity of the foam as a function of density is measured using a transient method based on the theory of the transient plane source technique. Finally, density variations of the resulting solid foam in several simple geometries are directly measured by sectioning and sampling mass, as well as through x-ray computed tomography. These density measurements will be useful for model validation once the complete model is implemented in an engineering code.

Experiments to Populate and Validate a Processing Model for Polyurethane Foam: Additional Data for Structural Foams

Energy Technology Data Exchange (ETDEWEB)

Rao, Rekha R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Giron, Nicholas Henry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Long, Kevin Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Russick, Edward M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-01-01

We are developing computational models to help understand manufacturing processes, final properties and aging of structural foam, polyurethane PMDI. Th e resulting model predictions of density and cure gradients from the manufacturing process will be used as input to foam heat transfer and mechanical models. BKC 44306 PMDI-10 and BKC 44307 PMDI-18 are the most prevalent foams used in structural parts. Experiments needed to parameterize models of the reaction kinetics and the equations of motion during the foam blowing stages were described for BKC 44306 PMDI-10 in the first of this report series (Mondy et al. 2014). BKC 44307 PMDI-18 is a new foam that will be used to make relatively dense structural supports via over packing. It uses a different catalyst than those in the BKC 44306 family of foams; hence, we expect that the reaction kineti cs models must be modified. Here we detail the experiments needed to characteriz e the reaction kinetics of BKC 44307 PMDI-18 and suggest parameters for the model based on these experiments. In additi on, the second part of this report describes data taken to provide input to the preliminary nonlinear visco elastic structural response model developed for BKC 44306 PMDI-10 foam. We show that the standard cu re schedule used by KCP does not fully cure the material, and, upon temperature elevation above 150°C, oxidation or decomposition reactions occur that alter the composition of the foam. These findings suggest that achieving a fully cured foam part with this formulation may be not be possible through therma l curing. As such, visco elastic characterization procedures developed for curing thermosets can provide only approximate material properties, since the state of the material continuously evolves during tests.

Preparation of novel magnetic polyurethane foam nanocomposites by using core-shell nanoparticles

OpenAIRE

Nikje,Mir Mohammad Alavi; Moghaddam,Sahebeh Tamaddoni; Noruzian,Maede

2016-01-01

Abstract Iron oxide magnetic nanoparticles (NP's) converted to the core- shell structres by reacting with by n-(2-aminoethyl)-3-aminopropyl trimethoxysilane (AEAP) incorporated in polyurethane flexible (PUF) foam formulations. Fourier transform spectra, thermal gravimetric analysis, scanning electron images, thermo-mechanical analysis and magnetic properties of the prepared nanocomposites were studied. Obtained data shown that by the increasing of the amine modified magnetic iron oxide NP's u...

Bio-based Polymer Foam from Soyoil

Science.gov (United States)

Bonnaillie, Laetitia M.; Wool, Richard P.

2006-03-01

The growing bio-based polymeric foam industry is presently lead by plant oil-based polyols for polyurethanes and starch foams. We developed a new resilient, thermosetting foam system with a bio-based content higher than 80%. The acrylated epoxidized soybean oil and its fatty acid monomers is foamed with pressurized carbon dioxide and cured with free-radical initiators. The foam structure and pore dynamics are highly dependent on the temperature, viscosity and extent of reaction. Low-temperature cure hinds the destructive pore coalescence and the application of a controlled vacuum results in foams with lower densities ˜ 0.1 g/cc, but larger cells. We analyze the physics of foam formation and stability, as well as the structure and mechanical properties of the cured foam using rigidity percolation theory. The parameters studied include temperature, vacuum applied, and cross-link density. Additives bring additional improvements: nucleating agents and surfactants help produce foams with a high concentration of small cells and low bulk density. Hard and soft thermosetting foams with a bio content superior to 80% are successfully produced and tested. Potential applications include foam-core composites for hurricane-resistant housing, structural reinforcement for windmill blades, and tissue scaffolds.

Preparation of novel magnetic polyurethane foam nanocomposites by using core-shell nanoparticles

Directory of Open Access Journals (Sweden)

Mir Mohammad Alavi Nikje

Full Text Available Abstract Iron oxide magnetic nanoparticles (NP's converted to the core- shell structres by reacting with by n-(2-aminoethyl-3-aminopropyl trimethoxysilane (AEAP incorporated in polyurethane flexible (PUF foam formulations. Fourier transform spectra, thermal gravimetric analysis, scanning electron images, thermo-mechanical analysis and magnetic properties of the prepared nanocomposites were studied. Obtained data shown that by the increasing of the amine modified magnetic iron oxide NP's up to 3% in the polymer matrix, thermal and magnetic properties improved in comparison with pristine foams. In addition, due to the presence of functional groups on the magnetic NP's surface, hard phases formation decrease in the bulk polymer and cause decreasing of glass transition temperature.

Morphological Parameters in Relation to the Electromagnetic Properties of Microcellular Thermoplastic Polyurethane Foam in X-Band Frequency Ranges

Directory of Open Access Journals (Sweden)

Mohammad Hassan Moeini

2017-04-01

Full Text Available Microcellular thermoplastic polyurethane foams are examined as absorbing materials in the X-band (8.2-12.4 GHz frequency range by means of experiment. In this work, we aim to establish relationships between foam morphology including cell size and air volume fraction and electromagnetic properties including absorption, transmission and reflection quality. Nanocomposites based on thermoplastic polyurethane containing carbon black were prepared by coagulation method. In this procedure 15 wt% carbon black-containing nanocomposite was converted to microcellular foams using batch foaming process and supercritical carbon dioxide as physical foaming agent. The morphology of the foams was evaluated by scanning electron microscopy. S-parameters of the samples were measured by a vector network analyzer (VNA and the effect of morphological parameters such as cell size and air volume fraction on the absorbing properties was investigated. We also established structure/properties relationships which were essential for further optimizations of the materials used in the construction of radar absorbing composites. Foaming reduced the percolation threshold of the nanocomposites due to the reduction in the average distance between nanoparticles. Foaming and dielectric constant reduction dropped the reflection percentage significantly. The increase in air volume fraction in the foam increased absorption per its weight, because of multiple scattering in composite media. The sensitivity of electromagnetic wave toward the variation of cell size is strongly weaker than that toward the variation of air volume fraction. Electromagnetic properties of the microcellular foams deviated a little from effective medium theories (EMTs. Air volume fraction of the cells was a function of cell size and smaller cells showed higher absorption.

Occupational allergic and irritant contact dermatitis in workers exposed to polyurethane foam

Directory of Open Access Journals (Sweden)

Marta Kieć-Świerczyńska

2014-04-01

Full Text Available Objectives: To evaluate sensitization to chemicals present in work environment after an outbreak of contact dermatitis in workers of vehicle equipment factory, exposed to polyurethane foam, based on 4,4'-diphenylmethane diisocyanate (MDI. Material and Methods: From among 300 employees, 21 individuals reporting work-related skin and/or respiratory tract symptoms underwent clinical examination, patch testing, skin prick tests, spirometry and MDI sIgE measurement in serum. Patch tests included isocyanates series, selected rubber additives, metals, fragrances, preservatives, and an antiadhesive agent. Results: Clinical examination revealed current eczema in the area of hands and/or forearms in 10 workers. Positive patch test reactions were found in 10 individuals, the most frequent to diaminodiphenylmethane and 4-phenylenediamine (7 persons. Reactions to an antiadhesive agent were assessed as irritant (5 workers. Except for sensitization to common aeroallergens, no significant abnormalities were found in the remaining tests. Occupational allergic contact dermatitis was diagnosed in 7 workers, irritant contact dermatitis in 10 and coexisiting allergic and irritant contact dermatitis in 3 workers. Conclusions: In workers manufacturing products from polyurethane foam, attention should be paid to the risk of developing contact dermatitis. Skin problems in our study group were attributable probably to insufficient protection of the skin.

Improving Ballistic Performance of Polyurethane Foam by Nanoparticle Reinforcement

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M. F. Uddin

2009-01-01

Full Text Available We report improving ballistic performance of polyurethane foam by reinforcing it with nanoscale TiO2 particles. Particles were dispersed through a sonic cavitation process and the loading of particles was 3 wt% of the total polymer. Once foams were reinforced, sandwich panels were made and impacted with fragment simulating projectiles (FSPs in a 1.5-inch gas gun. Projectile speed was set up to have complete penetration of the target in each experiment. Test results have indicated that sandwich with nanophased cores absorbed about 20% more kinetic energy than their neat counterpart. The corresponding increase in ballistic limit was around 12% over the neat control samples. The penetration phenomenon was also monitored using a high-speed camera. Analyses of digital images showed that FSP remained inside the nanophased sandwich for about 7 microseconds longer than that of a neat sandwich demonstrating improved energy absorption capability of the nanoparticle reinforced core. Failure modes for energy absorption have been investigated through a microscope and high-speed images.

Aluminum phosphate microcapsule flame retardants for flexible polyurethane foams

Science.gov (United States)

Zhang, Bin; Liu, Hong; Han, Jian

2018-04-01

In this study, highly efficient flame-retardant aluminum phosphate (ALP) microcapsules were synthesized from ALP and ammonium phosphomolybdate trihydrate. The chemical structure of the ALP microcapsules was characterized by scanning electron microscopy and elemental analysis, and the thermal degradation behavior was investigated by thermogravimetric analysis (TGA). Subsequently, flexible polyurethane (PU) foams were prepared with the ALP microcapsules. Limiting oxygen index (LOI) tests, vertical burning tests, smoke density rating (SDR), and cone calorimetric tests were employed to investigate the combustion of the materials. The results showed that the flexible PU foams with 15 parts per hundred polyol by weight (pphp) ALP microcapsules passed the vertical burning test and they had an increased LOI value of 28.5%. The SDR value for PU/20 pphp ALP microcapsule composites was about 16.0% and the SDR value for the pure PU was about 29.0%. The corresponding flame-retardant mechanism was investigated by Fourier transform infrared spectroscopy, TGA, Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC/MS) tests, and energy-dispersive X-ray spectrometry.

Improving Ballistic Performance of Polyurethane Foam by Nanoparticle Reinforcement

International Nuclear Information System (INIS)

Uddin, M.F.; Zainuddin, S.; Mahfuz, H.; Jeelani, S.

2009-01-01

We report improving ballistic performance of polyurethane foam by reinforcing it with nano scale TiO 2 particles. Particles were dispersed through a sonic cavitation process and the loading of particles was 3 wt % of the total polymer. Once foams were reinforced, sandwich panels were made and impacted with fragment simulating projectiles (FSPs) in a 1.5-inch gas gun. Projectile speed was set up to have complete penetration of the target in each experiment. Test results have indicated that sandwich with nano phased cores absorbed about 20% more kinetic energy than their neat counterpart. The corresponding increase in ballistic limit was around 12% over the neat control samples. The penetration phenomenon was also monitored using a high-speed camera. Analyses of digital images showed that FSP remained inside the nano phased sandwich for about 7 microseconds longer than that of a neat sandwich demonstrating improved energy absorption capability of the nanoparticle reinforced core. Failure modes for energy absorption have been investigated through a microscope and high-speed images.

Cryoinsulation Material Development to Mitigate Obsolescence Risk for Global Warming Potential Foams

Science.gov (United States)

Protz, Alison; Bruyns, Roland; Nettles, Mindy

2015-01-01

Cryoinsulation foams currently being qualified for the Space Launch System (SLS) core stage are nonozone- depleting substances (ODP) and are compliant with current environmental regulations. However, these materials contain the blowing agent HFC-245fa, a hydrofluorocarbon (HFC), which is a Global Warming Potential (GWP) substance. In August 2014, the Environmental Protection Agency (EPA) proposed a policy change to reduce or eliminate certain HFCs, including HFC-245fa, in end-use categories including foam blowing agents beginning in 2017. The policy proposes a limited exception to allow continued use of HFC and HFC-blend foam blowing agents for military or space- and aeronautics-related applications, including rigid polyurethane spray foams, but only until 2022.

40 CFR 63.1296 - Standards for slabstock flexible polyurethane foam production-HAP ABA equipment leaks.

Science.gov (United States)

2010-07-01

... polyurethane foam production-HAP ABA equipment leaks. 63.1296 Section 63.1296 Protection of Environment... production—HAP ABA equipment leaks. Each owner or operator of a new or existing slabstock affected source complying with the emission point specific limitation option provided in § 63.1293(a) shall control HAP ABA...

40 CFR 63.1295 - Standards for slabstock flexible polyurethane foam production-HAP ABA storage vessels.

Science.gov (United States)

2010-07-01

... polyurethane foam production-HAP ABA storage vessels. 63.1295 Section 63.1295 Protection of Environment... production—HAP ABA storage vessels. Each owner or operator of a new or existing slabstock affected source complying with the emission point specific limitation option provided in § 63.1293(a) shall control HAP ABA...

Polyurethane foam impregnated with lignin as a filler for the removal of crude oil from contaminated water

Energy Technology Data Exchange (ETDEWEB)

Santos, O.S.H. [Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, CEP: 31.270-901 (Brazil); Coelho da Silva, Mercês [Engenharia de Materiais, Universidade Federal de Itajubá—UNIFEI, Campus Universitário de Itabira. Itabira, Minas Gerais, CEP: 35.903-087 (Brazil); Silva, V.R.; Mussel, W.N. [Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, CEP: 31.270-901 (Brazil); Yoshida, M.I., E-mail: mirene@ufmg.br [Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, CEP: 31.270-901 (Brazil)

2017-02-15

Highlights: • The presence of lignin in polyurethane foams increased oil sorption capacity. • The presence of lignin resulted in a decrease in the hydrophobicity of the foams. • Langmuir isotherm predicted a maximum oil adsorption of 28.9 g g{sup −1} by the PUF-10. • ΔG° (−4.4 kJ mol{sup −1}) indicated that adsorption process by PUF-10 was spontaneous. • The recyclability of the foam showed efficiency greater than 95% after five cycles. - Abstract: The present study describes the influence of the concentration of lignin when used as a filler in polyurethane foam for crude oil sorption. The foams (lignin 0–20 wt%) were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis, contact angle and density. The FTIR analysis confirmed urethane linkage formation, showing that the chemical structure of the polymer was preserved, despite the addition of different lignin concentrations. Thermogravimetric analysis showed that the presence of lignin has altered the onset temperature (T{sub onset}) of the foams, decreasing as the concentration of lignin is increased. The contact angle analysis showed a decrease in the hydrophobicity of the foams with increasing lignin concentration. All modified foams showed an improvement in the oil sorption capacity in a PUF/oil/water system, and the PUF-10 showed an improvement of about 35.5% compared to the PUF-blank. The Langmuir isotherm showed a better fit to the data and predicted a maximum oil adsorption of 28.9 g g{sup −1} by the PUF-10. The ΔG° value of −4.4 kJ mol{sup −1} indicated that crude oil adsorption process by PUF-10 was spontaneous. The results of reuse of the PUF-10 showed that oil removal efficiency remained greater than 95% after five consecutive cycles.

MANUAL: BEST MANAGEMENT PRACTICES FOR POLLUTION PREVENTION IN THE SLABSTOCK AND MOLDED FLEXIBLE POLYURETHANE FOAM INDUSTRY

Science.gov (United States)

The 1990 Clean Air Act Amendments require EPA to develop standards for major emission sources of 189 hazardous air pollutants (HAPs). EPA has identified the flexible polyurethane foam industry as a large emitter of HAPs and has slated the industry for regulation under Title III, ...

Investigation of Industrial Polyurethane Foams Modified with Antimicrobial Copper Nanoparticles

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Maria Chiara Sportelli

2016-07-01

Full Text Available Antimicrobial copper nanoparticles (CuNPs were electrosynthetized and applied to the controlled impregnation of industrial polyurethane foams used as padding in the textile production or as filters for air conditioning systems. CuNP-modified materials were investigated and characterized morphologically and spectroscopically, by means of Transmission Electron Microscopy (TEM, and X-ray Photoelectron Spectroscopy (XPS. The release of copper ions in solution was studied by Electro-Thermal Atomic Absorption Spectroscopy (ETAAS. Finally, the antimicrobial activity of freshly prepared, as well as aged samples—stored for two months—was demonstrated towards different target microorganisms.

Fire hazards in the use of polyurethane foam with special consideration given to its use in the mining industry

Energy Technology Data Exchange (ETDEWEB)

Florschuetz, P.; Hoffmann, R.; Pfeiffer, J.

1980-08-01

Discusses results from combustion tests conducted with polyurethane (PUR) foam and polyisocyanurate (PIC) foam, which are employed in mine construction, thermal insulation, and coating of coal preparation equipment. Fire point, inflammation point, flame propagation, carbon monoxide content in the fumes and other parameters were investigated. Coating the foam with a fire resistant chemical agent delayed the combustion process. Mixing foam with various quantities of foam components influenced the combustion process as well. The combustion results are presented in tables. It is concluded that the user's instructions for producing foam should be strictly adhered to and that larger sections of insulation by these foams in underground mines can only be permitted when additional protection measures are undertaken. (5 refs.) (In German)

Treatment of low level radioactive liquid wastes using composite ion-exchange resins based on polyurethane foam

International Nuclear Information System (INIS)

Rao, S.V.S.; Lekshmi, R.; Mani, A.G.S.; Sinha, P.K.

2010-01-01

Composite ion-exchange resins were prepared by coating copper-ferrocyanide (CFC) and hydrous manganese oxide (HMO) powders on polyurethane (PU) foam. Polyvinyl acetate/Acetone was used as a binder. The foam was loaded with about five times its weight with CFC and HMO powders. The distribution coefficients of CFC-PU foam and HMO-PU foam for cesium and strontium respectively were estimated. Under similar conditions the HMO-PU foam showed higher capacity as well as better kinetics for removal of strontium than CFC-PU foam for Cs. The pilot plant scale studies were conducted using a mixed composite ion-exchange resin bed. About 1000 bed volumes could be passed before attaining a DF of 10 from an initial value of 60-80. The spent resin was digested in alkaline KMnO 4 and the digested liquid was fixed in cement matrix. The matrices were characterized with respect to compressive strength and leach resistance. (author)

Application of Auxetic Foam in Sports Helmets

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Leon Foster

2018-03-01

Full Text Available This investigation explored the viability of using open cell polyurethane auxetic foams to augment the conformable layer in a sports helmet and improve its linear impact acceleration attenuation. Foam types were compared by examining the impact severity on an instrumented anthropomorphic headform within a helmet consisting of three layers: a rigid shell, a stiff closed cell foam, and an open cell foam as a conformable layer. Auxetic and conventional foams were interchanged to act as the helmet’s conformable component. Attenuation of linear acceleration was examined by dropping the combined helmet and headform on the front and the side. The helmet with auxetic foam reduced peak linear accelerations (p < 0.05 relative to its conventional counterpart at the highest impact energy in both orientations. Gadd Severity Index reduced by 11% for frontal impacts (38.9 J and 44% for side impacts (24.3 J. The conformable layer within a helmet can influence the overall impact attenuating properties. The helmet fitted with auxetic foam can attenuate impact severity more than when fitted with conventional foam, and warrants further investigation for its potential to reduce the risk of traumatic brain injuries in sport specific impacts.

Preparation of polyurethane foams using liquefied oil palm mesocarp fibre (OPMF) and renewable monomer from waste cooking oil

Science.gov (United States)

Kormin, Shaharuddin; Rus, Anika Zafiah M.; Azahari, M. Shafiq M.

2017-09-01

The aim of this research is the production of polyurethane (PU) foams with biopolyols from liquefied oil palm mesocarp fibre (OPMF) and renewable monomer. Liquefaction of OPMF was studied using polyhydric alcohol (PA) which is PEG-400 as liquefaction solvents in conventional glass flask. In the second part of this paper was obtained the PU foams which presented good results when compared with commercial foams and include polyols from of fossil fuels. PU foams were prepared by mixing liquefied OPMF biopolyol, renewable monomer from waste cooking, additives and methylene diphenyl diisocyanate (MDI). Water was used as an environmental friendly blowing agent. The factors that influence the cell structure of foams (i.e., catalyst, surfactant, dosage of blowing agent, and mass ratio of biopolyol to renewable monomer were studied. The synthesized PU foams were characterized by FTIR and SEM. The formulation of the PU foams should be improved, but the results show that is possible the use biopolyols and renewable monomer to produce industrial foams with lower cost.

CFC alternatives for thermal insulation foams

Energy Technology Data Exchange (ETDEWEB)

Shankland, I.R. (Allied-Signal Inc., Buffalo, NY (US))

1990-03-01

Low density polymeric foam materials expanded with chlorofluorocarbon (CFC) blowing agents have found widespread use as highly efficient thermal insulation materials in the construction, refrigeration appliance and transportation industries. The advent of regulations which are reducing the production and consumption of the fully halogenated CFCs for environmental reasons has prompted the development of environmentally acceptable substitutes for the CFC blowing agents. This paper summarizes the physical properties and performance of the leading alternatives for CFC-11, which is used to expand rigid polyurethane and polyisocyanurate foams, and the leading alternatives for CFC-12 which is used to expand extruded polystyrene board foam. Although the alternatives, HCFC-123 and HCFC-14lb for CFC-11 and HCFC142b and HCFC-124 for CFC-12, are not perfect matches from the performance viewpoint, they represent the optimum choice given the constraints on environmental acceptability, toxicity, flammability and performance. (author).

System Description for the K-25/K-27 D and D Project Polyurethane Foam Delivery System, East Tennessee Technology Park, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Boris, G.

2008-01-01

The Foam Delivery System used in the decontamination and decommissioning (D and D) project for the K-25/K-27 Buildings at the East Tennessee Technology Park (ETTP) is comprised of a trailer-mounted Gusmer(reg s ign) H20/35 Pro-TEC Proportioning Unit and the associated equipment to convey electrical power, air, and foam component material to the unit. This high-pressure, plural-component polyurethane foam pouring system will be used to fill process gas and non-process equipment/piping (PGE/P) within the K-25/K-27 Buildings with polyurethane foam to immobilize contaminants prior to removal. The system creates foam by mixing isocyanate and polyol resin (Resin) component materials. Currently, the project plans to utilize up to six foaming units simultaneously during peak foaming activities. Also included in this system description are the foam component material storage containers that will be used for storage of the component material drums in a staging area outside of the K-25/K-27 Buildings. The Foam Delivery System and foam component material storage enclosures (i.e., Foaming Component Protective Enclosures) used to store polymeric methylene diphenyl diisocyanate (PMDI) component material are identified as Safety Significant (SS) Structures, Systems and Components (SSC) in the Documented Safety Analysis (DSA) for the project, Documented Safety Analysis for the K-25 and K-27 Facilities at the East Tennessee Technology Park, Oak Ridge, Tennessee, DSA-ET-K-25/K-27-0001

Response to fire, thermal insulation and acoustic performance of rigid polyurethane agglomerates with addition of natural fiber

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Marcos Vinicius Rizzo

2015-03-01

Full Text Available This paper aims to reuse rigid polyurethane waste in the preparation of composites with the addition of banana fibers and cellulose in order to qualify the acoustic performance, thermal insulation and reaction to fire the material with the addition of 7% of polysulfone. Agglomerated with 100% of polyurethane and either with 20% of banana fiber or 20% of cellulose were characterized in the sound transmission loss, thermal conductivity and reaction to fire, take into account variations in the granulometry of the solid polyurethane and type of pressing. Natural fiber composites had lower thermal conductivity, higher acoustic insulation in medium frequencies and the addition of polysulfone delayed the total time of firing the material.

EFFECTIVENESS OF USING POLYURETHANE FOAM TO REDUCE HEAT LOSS IN THE PREMISES FOR BREEDING

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Medvedev A.Y.

2013-10-01

Full Text Available It is proved that the use of polyurethane foam insulation for the purpose of walling premises for breeding allows them to halve the deficit of heat in winter. Because of this more efficient use of feed, increases the intensity and the level of growth of young comprehensive energp $rocess in the energy of live weight gain of cattle while increasing the profitability of its cultivation for meat.

All-dielectric invisibility cloaks made of BaTiO3-loaded polyurethane foam

International Nuclear Information System (INIS)

Bao Di; Rajab, Khalid Z; Hao Yang; Kallos, Efthymios; Tang, Wenxuan; Argyropoulos, Christos; Piao Yongzhe; Yang Shoufeng

2011-01-01

Transformation optics has led the way in the development of electromagnetic invisibility cloaks from science fiction to engineering practice. Invisibility cloaks have been demonstrated over a wide range of the electromagnetic spectrum, and with a variety of different fabrication techniques. However, all previous schemes have relied on the use of metamaterials consisting of arrays of sub-wavelength inclusions. We report on the first cloaking structure made of a high-κ dielectric-loaded foam mixture. A polyurethane foam mixed with different ratios of barium titanate is used to produce the required range of permittivities, and the invisibility cloak is demonstrated to work for all incident angles over a wide range of microwave frequencies. This method will greatly facilitate the development and large-scale manufacture of a wide range of transformation optics-based structures. (paper)

Preparation and Sound Absorption Properties of a Barium Titanate/Nitrile Butadiene Rubber–Polyurethane Foam Composite with Multilayered Structure

Science.gov (United States)

Jiang, Xueliang; Yang, Zhen; Wang, Zhijie; Zhang, Fuqing; You, Feng

2018-01-01

Barium titanate/nitrile butadiene rubber (BT/NBR) and polyurethane (PU) foam were combined to prepare a sound-absorbing material with an alternating multilayered structure. The effects of the cell size of PU foam and the alternating unit number on the sound absorption property of the material were investigated. The results show that the sound absorption efficiency at a low frequency increased when decreasing the cell size of PU foam layer. With the increasing of the alternating unit number, the material shows the sound absorption effect in a wider bandwidth of frequency. The BT/NBR-PU foam composites with alternating multilayered structure have an excellent sound absorption property at low frequency due to the organic combination of airflow resistivity, resonance absorption, and interface dissipation. PMID:29565321

Preparation and Sound Absorption Properties of a Barium Titanate/Nitrile Butadiene Rubber–Polyurethane Foam Composite with Multilayered Structure

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Xueliang Jiang

2018-03-01

Full Text Available Barium titanate/nitrile butadiene rubber (BT/NBR and polyurethane (PU foam were combined to prepare a sound-absorbing material with an alternating multilayered structure. The effects of the cell size of PU foam and the alternating unit number on the sound absorption property of the material were investigated. The results show that the sound absorption efficiency at a low frequency increased when decreasing the cell size of PU foam layer. With the increasing of the alternating unit number, the material shows the sound absorption effect in a wider bandwidth of frequency. The BT/NBR-PU foam composites with alternating multilayered structure have an excellent sound absorption property at low frequency due to the organic combination of airflow resistivity, resonance absorption, and interface dissipation.

Preparation and Sound Absorption Properties of a Barium Titanate/Nitrile Butadiene Rubber-Polyurethane Foam Composite with Multilayered Structure.

Science.gov (United States)

Jiang, Xueliang; Yang, Zhen; Wang, Zhijie; Zhang, Fuqing; You, Feng; Yao, Chu

2018-03-22

Barium titanate/nitrile butadiene rubber (BT/NBR) and polyurethane (PU) foam were combined to prepare a sound-absorbing material with an alternating multilayered structure. The effects of the cell size of PU foam and the alternating unit number on the sound absorption property of the material were investigated. The results show that the sound absorption efficiency at a low frequency increased when decreasing the cell size of PU foam layer. With the increasing of the alternating unit number, the material shows the sound absorption effect in a wider bandwidth of frequency. The BT/NBR-PU foam composites with alternating multilayered structure have an excellent sound absorption property at low frequency due to the organic combination of airflow resistivity, resonance absorption, and interface dissipation.

Adjustable Polyurethane Foam as Filling Material for a Novel Spondyloplasty: Biomechanics and Biocompatibility.

Science.gov (United States)

Jiang, Hongzhen; Sitoci-Ficici, Kerim Hakan; Reinshagen, Clemens; Molcanyi, Marek; Zivcak, Jozef; Hudak, Radovan; Laube, Thorsten; Schnabelrauch, Matthias; Weisser, Jürgen; Schäfer, Ute; Pinzer, Thomas; Schackert, Gabriele; Zhang, Xifeng; Wähler, Mario; Brautferger, Uta; Rieger, Bernhard

2018-04-01

To investigate the biomechanics and biocompatibility of polyurethane (PU) foam with adjustable stiffness as a filling material for a novel spondyloplasty that is designed to reduce the risk of postoperative adjacent level fractures. Sixty individual porcine lumbar vertebrae were randomly split into 4 groups: A, B, C, and D. Group A served as unmodified vertebral body controls. Groups B, C, and D consisted of hollowed vertebral bodies. Vertebrae of groups C and D were filled with adjustable PU foams of different stiffness. The compressive strength and stiffness of vertebrae from groups A-D were recorded and analyzed. 3T3 mouse fibroblasts were cultured with preformed PU foams for 4 days to test biocompatibility. The strength and stiffness of the hollowed groups were lower than in group A. However, the differences were not statistically significant between group A and group C (P > 0.05), and were obviously different between group A and group B or group D (P < 0.01 and <0.05, respectively). Moreover, the strength and stiffness after filling foams in group C or group D were significantly greater than in group B (P < 0.01 and <0.05, respectively). Live/dead staining of 3T3 cells confirmed the biocompatibility of the PU foam. The new PU foam shows adaptability regarding its stiffness and excellent cytocompatibility in vitro. The results support the clinical translation of the new PU foams as augmentation material in the development of a novel spondyloplasty. Copyright © 2018 Elsevier Inc. All rights reserved.

Modeling Heat Transfer and Pressurization of Polymeric Methylene Diisocyanate (PMDI) Polyurethane Foam in a Sealed Container.

Energy Technology Data Exchange (ETDEWEB)

Scott, Sarah Nicole

2018-01-01

Polymer foam encapsulants provide mechanical, electrical, and thermal isolation in engineered systems. It can be advantageous to surround objects of interest, such as electronics, with foams in a hermetically sealed container to protect the electronics from hostile en vironments, such as a crash that produces a fire. However, i n fire environments, gas pressure from thermal decomposition of foams can cause mechanical failure of the sealed system . In this work, a detailed study of thermally decomposing polymeric methylene diisocyanate (PMDI) - polyether - polyol based polyurethane foam in a sealed container is presented . Both experimental and computational work is discussed. Three models of increasing physics fidelity are presented: No Flow, Porous Media, and Porous Media with VLE. Each model us described in detail, compared to experiment , and uncertainty quantification is performed. While the Porous Media with VLE model matches has the best agreement with experiment, it also requires the most computational resources.

Effective Thermal Conductivity of Open Cell Polyurethane Foam Based on the Fractal Theory

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Kan Ankang

2013-01-01

Full Text Available Based on the fractal theory, the geometric structure inside an open cell polyurethane foam, which is widely used as adiabatic material, is illustrated. A simplified cell fractal model is created. In the model, the method of calculating the equivalent thermal conductivity of the porous foam is described and the fractal dimension is calculated. The mathematical formulas for the fractal equivalent thermal conductivity combined with gas and solid phase, for heat radiation equivalent thermal conductivity and for the total thermal conductivity, are deduced. However, the total effective heat flux is the summation of the heat conduction by the solid phase and the gas in pores, the radiation, and the convection between gas and solid phase. Fractal mathematical equation of effective thermal conductivity is derived with fractal dimension and vacancy porosity in the cell body. The calculated results have good agreement with the experimental data, and the difference is less than 5%. The main influencing factors are summarized. The research work is useful for the enhancement of adiabatic performance of foam materials and development of new materials.

The influence of polyol type on cell geometry and the thermal stability of polyurethane foams

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Prendžov Slobodan J.

2006-01-01

Full Text Available The aim of this study was to examine the influence of substituting defined amounts of polyol Voranol 3322 by polyol Voranol CP 1055 on the cell geometry and thermal stability of the synthesized flexible polyurethane foams. The influence of the amount of antipyrene on the cell geometry and their thermal stability was also investigated. The following components were used in the synthesis of the polyurethanes: a mixture of two polyols (Voranol 3322 with the hydroxyl number 47 mg KOH/g, mean molecular mass 3400 and Voranol CP 1055 with the hydroxyl number 156 mg KOH/g, mean molecular mass 1000, toluene discarnate as the isocyanate component, a combination of an organic-metallic compound and a tertiary amine as catalysts, surfactant and water as the coreactant. The thermal stability was determined by thermogravimetric analysis (in a nitrogen atmosphere. The cell geometry was analyzed by optical microscopy. Examination of the cell geometry revealed different cell shapes. The form factor as an indicator of cell deviation from spherical shape increased (more round forms were observed with increasing amount of Voranol CP 1055. The TG examination showed that specimens with 6 and 8 g of Voranol 3322 substituted by Voranol CP 1055 completely degraded at 350 °C, while foams with 10 and 12 g of Voranol 3322 substituted by Voranol CP 1055 displayed lower mass loss at higher temperatures and had residual masses of 46 % and 43 % at 600°C respectively. The addition of antipyrene in an amount of 1% (based on the amount of polyol contributed to improved thermal stability, no visible color change of the specimen tested at 210°C for 40 minutes, and to rounder cell forms. Considering the obtained results it can be concluded that an increase in the amount of Voranol CP 1055 yielded more spherically shaped cells and better thermal stability of the synthesized flexible polyurethane foams. The addition of antipyrene improves the thermal stability and the cell geometry.

Polyurethane foams obtained from residues of PET manufacturing and modified with carbon nanotubes

International Nuclear Information System (INIS)

Stiebra, L; Cabulis, U; Knite, M

2016-01-01

In this work we report the preparation of rigid microcellular polyurethane/carbon nanotube nanocomposites with different CNT loadings (0.09-0.46%) and various isocyanate indexes (110-260). Water was used as a blowing agent for samples. Density of all obtained samples – 200 ± 10 kg/m 3 . Electrical properties, as well as heat conductivity, cellular structure and mechanical properties of these nanocomposites were investigated. (paper)

Polyurethane foams obtained from residues of PET manufacturing and modified with carbon nanotubes

Science.gov (United States)

Stiebra, L.; Cabulis, U.; Knite, M.

2016-04-01

In this work we report the preparation of rigid microcellular polyurethane/carbon nanotube nanocomposites with different CNT loadings (0.09-0.46%) and various isocyanate indexes (110-260). Water was used as a blowing agent for samples. Density of all obtained samples - 200 ± 10 kg/m3. Electrical properties, as well as heat conductivity, cellular structure and mechanical properties of these nanocomposites were investigated.

Polyurethane Filler for Electroplating

Science.gov (United States)

Beasley, J. L.

1984-01-01

Polyurethane foam proves suitable as filler for slots in parts electroplated with copper or nickel. Polyurethane causes less contamination of plating bath and of cleaning and filtering tanks than wax fillers used previously. Direct cost of maintenance and indirect cost of reduced operating time during tank cleaning also reduced.

Polyurethane foam pica in a patient with excessive interdialytic weight gain

Science.gov (United States)

Iyasere, Osasuyi; Allington, Ying; Cafferkey, Michele

2010-01-01

Maintaining fluid balance in haemodialysis patients is important because of the adverse effects of excessive interdialytic weight gain. This often requires fluid restriction that patients often struggle with. We report a case of a 31-year-old female diabetic patient on haemodialysis with repeated excessive interdialytic weight gains despite fluid restriction and dry weight adjustment. It was subsequently discovered that she devised an unusual, albeit unsuccessful, strategy of eating the polyurethane foam from her dialysis chair while increasing her fluid intake hoping that it would absorb excess water in the gut! This under-diagnosed phenomenon known as pica has been reported in renal patients with substances such as ice, clay and baking soda. PMID:22767521

Development of Styrene-Grafted Polyurethane by Radiation-Based Techniques

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Jin-Oh Jeong

2016-06-01

Full Text Available Polyurethane (PU is the fifth most common polymer in the general consumer market, following Polypropylene (PP, Polyethylene (PE, Polyvinyl chloride (PVC, and Polystyrene (PS, and the most common polymer for thermosetting resins. In particular, polyurethane has excellent hardness and heat resistance, is a widely used material for electronic products and automotive parts, and can be used to create products of various physical properties, including rigid and flexible foams, films, and fibers. However, the use of polar polymer polyurethane as an impact modifier of non-polar polymers is limited due to poor combustion resistance and impact resistance. In this study, we used gamma irradiation at 25 and 50 kGy to introduce the styrene of hydrophobic monomer on the polyurethane as an impact modifier of the non-polar polymer. To verify grafted styrene, we confirmed the phenyl group of styrene at 690 cm−1 by Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR and at 6.4–6.8 ppm by 1H-Nuclear Magnetic Resonance (1H-NMR. Scanning Electron Microscope (SEM, X-ray Photoelectron Spectroscopy (XPS, Thermogravimetric Analysis (TGA and contact angle analysis were also used to confirm styrene introduction. This study has confirmed the possibility of applying high-functional composite through radiation-based techniques.

ENGINEERING DESIGN: EICOSANE MICROCAPSULES SYNTHESIS AND APPLICATION IN POLYURETHANE FOAMS AIMING TO DIMINISH WHEELCHAIR CUSHION EFFECT ON SKIN TEMPERATURE

Directory of Open Access Journals (Sweden)

ELISA M. BERETTA

2016-12-01

Full Text Available Thermal comfort of wheelchairs still requires improvements, since users remain on the chair for as long as 12 h a day. Increased sweating makes the skin more susceptible to colonization by fungi and bacteria, and may cause pressure ulcers. In this sense, the microencapsulation of Phase-Change Materials (PCMs may help to enhance wheelchair cushion comfort by regulating heat exchange. This study describes the production of PCM microcapsules and their application in flexible polyurethane foams after expansion, and assesses improvements in heat exchange. Microcapsules with eicosane core coated with melamine-formaldehyde were produced. Eicosane is a thermoregulation agent whose phase-change temperature is near that of the human body’s. Microcapsules were characterized by thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and Fourier transform infrared spectroscopy. Then, microcapsules were applied on polyurethane foams by vacuum filtration and high-pressure air gun. Samples were exposed to a heat source and analysed by infrared thermography. The results indicate that thermal load increased in samples treated with microcapsules, especially by pressure air gun, and show that it is possible to enhance thermal comfort in wheelchair seats. Thereby, this study contributes to enhance quality of life for wheelchair users, focusing on thermal comfort provided by cushion seats made from PU foam.

Effect of lignin derivatives in the bio-polyols from microwave liquefied bamboo on the properties of polyurethane foams

Science.gov (United States)

Jiulong Xie; Jinqiu Qi; Chung-Yun Hse; Todd F. Shupe

2014-01-01

Bamboo residues were subjected to a microwave-assisted liquefaction process for the production of crude bio-polyols (CBP). The fractionated bio-polyols (FBP) were obtained by the removal of lignin derivatives from the crude bio-polyols (CBP) using a simple method. Polyurethane (PU) foams were successfully prepared from both CBP and FBP. The object of this study was to...

Medium optimization for nuclease P1 production by Penicillium citrinum in solid-state fermentation using polyurethane foam as inert carrier

NARCIS (Netherlands)

Zhu, Y.; Knol, W.; Smits, J.P.; Bol, J.

1996-01-01

A solid-state fermentation system, using polyurethane foam as an inert carrier, was used for the production of nuclease P1 by Penicillium citrinum. Optimization of nuclease P1 production was carried out using a synthetic liquid medium. After a two-step medium optimization using a fractional

Ventilation Guidance To Promote the Safe Use of Spray Polyurethane Foam (SPF) Insulation, Incluyendo la Versión de Español

Science.gov (United States)

This guidance describes basic ventilation principles and strategies to help protect workers and building occupants and promote the safe use of spray polyurethane foam (SPF) insulation. Guia para la ventilacion sobre la application del aerosol de espuma.

Tensile and fracture behavior of polymer foams

International Nuclear Information System (INIS)

Kabir, Md. E.; Saha, M.C.; Jeelani, S.

2006-01-01

Tensile and mode-I fracture behavior of cross-linked polyvinyl chloride (PVC) and rigid polyurethane (PUR) foams are examined. Tension tests are performed using prismatic bar specimens and mode-I fracture tests are performed using single edge notched bend (SENB) specimens under three-point bending. Test specimens are prepared from PVC foams with three densities and two different levels of cross-linking, and PUR foam with one density. Tension and quasi-static fracture tests are performed using a Zwick/Rowell test machine. Dynamic fracture tests are performed using a DYNATUP model 8210 instrumented drop-tower test set up at three different impact energy levels. Various parameters such as specimen size, loading rate, foam density, cross-linking, crack length, cell orientation (flow and rise-direction) and solid polymer material are studied. It is found that foam density and solid polymer material have a significant effect on tensile strength, modulus, and fracture toughness of polymer foams. Level of polymer cross-linking is also found to have a significant effect on fracture toughness. The presence of cracks in the rise- and flow direction as well as loading rate has minimal effect. Dynamic fracture behavior is found to be different as compared to quasi-static fracture behavior. Dynamic fracture toughness (K d ) increases with impact energy. Examination of fracture surfaces reveals that the fracture occurs in fairly brittle manner for all foam materials

Flexible and Lightweight Pressure Sensor Based on Carbon Nanotube/Thermoplastic Polyurethane-Aligned Conductive Foam with Superior Compressibility and Stability.

Science.gov (United States)

Huang, Wenju; Dai, Kun; Zhai, Yue; Liu, Hu; Zhan, Pengfei; Gao, Jiachen; Zheng, Guoqiang; Liu, Chuntai; Shen, Changyu

2017-12-06

Flexible and lightweight carbon nanotube (CNT)/thermoplastic polyurethane (TPU) conductive foam with a novel aligned porous structure was fabricated. The density of the aligned porous material was as low as 0.123 g·cm -3 . Homogeneous dispersion of CNTs was achieved through the skeleton of the foam, and an ultralow percolation threshold of 0.0023 vol % was obtained. Compared with the disordered foam, mechanical properties of the aligned foam were enhanced and the piezoresistive stability of the flexible foam was improved significantly. The compression strength of the aligned TPU foam increases by 30.7% at the strain of 50%, and the stress of the aligned foam is 22 times that of the disordered foam at the strain of 90%. Importantly, the resistance variation of the aligned foam shows a fascinating linear characteristic under the applied strain until 77%, which would benefit the application of the foam as a desired pressure sensor. During multiple cyclic compression-release measurements, the aligned conductive CNT/TPU foam represents excellent reversibility and reproducibility in terms of resistance. This nice capability benefits from the aligned porous structure composed of ladderlike cells along the orientation direction. Simultaneously, the human motion detections, such as walk, jump, squat, etc. were demonstrated by using our flexible pressure sensor. Because of the lightweight, flexibility, high compressibility, excellent reversibility, and reproducibility of the conductive aligned foam, the present study is capable of providing new insights into the fabrication of a high-performance pressure sensor.

Testing of Disposable Protective Garments Against Isocyanate Permeation From Spray Polyurethane Foam Insulation.

Science.gov (United States)

Mellette, Michael P; Bello, Dhimiter; Xue, Yalong; Yost, Michael; Bello, Anila; Woskie, Susan

2018-05-12

Diisocyanates (isocyanates), including methylene diphenyl diisocyanate (MDI), are the primary reactive components of spray polyurethane foam (SPF) insulation. They are potent immune sensitizers and a leading cause of occupational asthma. Skin exposure to isocyanates may lead to both irritant and allergic contact dermatitis and possibly contribute to systemic sensitization. More than sufficient evidence exists to justify the use of protective garments to minimize skin contact with aerosolized and raw isocyanate containing materials during SPF applications. Studies evaluating the permeation of protective garments following exposure to SPF insulation do not currently exist. To conduct permeation testing under controlled conditions to assess the effectiveness of common protective gloves and coveralls during SPF applications using realistic SPF product formulations. Five common disposable garment materials [disposable latex gloves (0.07 mm thickness), nitrile gloves (0.07 mm), vinyl gloves (0.07 mm), polypropylene coveralls (0.13 mm) and Tyvek coveralls (0.13 mm)] were selected for testing. These materials were cut into small pieces and assembled into a permeation test cell system and coated with a two-part slow-rise spray polyurethane foam insulation. Glass fiber filters (GFF) pretreated with 1-(9-anthracenylmethyl)piperazine) (MAP) were used underneath the garment to collect permeating isocyanates. GFF filters were collected at predetermined test intervals between 0.75 and 20.00 min and subsequently analyzed using liquid chromatography-tandem mass spectrometry. For each garment material, we assessed (i) the cumulative concentration of total isocyanate, including phenyl isocyanate and three MDI isomers, that effectively permeated the material over the test time; (ii) estimated breakthrough detection time, average permeation rate, and standardized breakthrough time; from which (iii) recommendations were developed for the use of similar protective garments following

Polyurethane - positioning aids in radiotherapy

International Nuclear Information System (INIS)

Alzen, G.; Boeck, E.G.; Thelen, M.; Kutzner, J.

1985-01-01

A simple and cheap method is described for the manufacturing of individual positioning aids made of foamed polyurethane. Some examples are given to demonstrate the applicability of these positioning aids for the irradiation of different body regions. The reproducibility of the radiation field in the head and neck area was investigated with and without positioning aid. It was proved that the field is adjusted more exactly when positioning aids are applied. The dosimetric investigations performed showed a negligible influence of foamed polyurethane on the radiation quality. So the positioning aids could be left within the radiation field when drawing the field borders. (orig.) [de

3D simulation of polyurethane foam injection and reacting mold flow in a complex geometry

Science.gov (United States)

Özdemir, İ. Bedii; Akar, Fırat

2018-05-01

The aim of the present work is to develop a flow model which can be used to determine the paths of the polyurethane foam in the mold filling process of a refrigerator cabinet so that improvements in the distribution and the size of the venting holes can be achieved without the expensive prototyping and experiments. For this purpose, the multi-component, two-phase chemically reacting flow is described by Navier Stokes and 12 scalar transport equations. The air and the multi-component foam zones are separated by an interface, which moves only with advection since the mass diffusion of species are set zero in the air zone. The inverse density, viscosity and other diffusion coefficients are calculated by a mass fraction weighted average of the corresponding temperature-dependent values of all species. Simulations are performed in a real refrigerator geometry, are able to reveal the problematical zones where air bubbles and voids trapped in the solidified foam are expected to occur. Furthermore, the approach proves itself as a reliable design tool to use in deciding the locations of air vents and sizing the channel dimensions.

PERFORMANCE OF A BIOTRICKLING FILTER EMPLOYING THIOBACILLUS THIOPARUS IMMOBILIZED ON POLYURETHANE FOAM FOR HYDROGEN SULFIDE REMOVAL

Directory of Open Access Journals (Sweden)

N. Abdehagh

2011-09-01

Full Text Available The removal of hydrogen sulfide (H2S from contaminated airstream was studied in a biotrickling filter (BTF packed with open-pore polyurethane foam as a carrier of Thiobacillus thioparus (DSMZ5368 with counter current gas/liquid flows. The effect of operating parameters on BTF performance was studied. Experiments were performed at different Empty Bed Residence Times (EBRT from 9 to 45 seconds, and different initial H2S concentration from 25 to 85 ppm. The results showed reasonable performance of the BTF, in H2S removal from the synthetic gas stream. However, the performance was somewhat lower than other studies in BTF in which either Thiobacillus thioparus with other packings or polyurethane foam with other microbial cultures were used. The effect of liquid recirculation rate (LRR in the range of 175-525 ml/min (0.46-1.34 m/h on BTF performance was also studied. Results showed that increasing LRR from 175 to 350 mL/min resulted in significant enhancement of H2S removal efficiency, but further increase in LRR up to 525 mL/min had an insignificant effect. H2S elimination at different heights of the bed was studied and it was found that decrease in EBRT results in more homogeneous removal of the pollutant in BTF. Determination of microbial species in the BTF after 100 days performance showed that during BTF operation the only H2S degrading specie was Thiobacillus thioparus.

The influence of low air pressure on horizontal flame spread over flexible polyurethane foam and correlative smoke productions

International Nuclear Information System (INIS)

Tu, Ran; Zeng, Yi; Fang, Jun; Zhang, Yongming

2016-01-01

Highlights: • Quasi two-dimensional flame spreading behavior of flexible polyurethane (FPU) foam was investigated. • Theoretical correlation of pressure effects on global burning rate was proposed. • The influence of pressure on plume and ceiling jet temperatures was studied theoretically. • Pressure effects on soot formation and CO concentration were analyzed. - Abstract: Pressure effects on quasi two-dimensional flexible polyurethane (FPU) foam flame spreading behavior, typical product concentrations, and smoke detector responses were investigated by comparative experiments under different ambient pressures of 99.8 kPa (in Hefei) and 66.5 kPa (in Lhasa), respectively. First, significant decreases of flame spreading velocity and burning rate were observed under low pressure condition. Averaged global burning rate was found to be dependent on pressure, with an exponential factor of 4/3 theoretically based on pressure modeling. Second, the maximum temperature at a given position in axial thermal plume showed insensitivity to pressure, yet the maximum temperature in ceiling jet was obviously higher. Third, the low pressure was shown to have no effect on soot particles size distribution by scan electron microscopy (SEM) imaging. However, the soot number concentration decreased with reduced pressure attributed to the much slower soot formation rate under low pressure. This result would further have an interesting influence on the response signals of photoelectric detector and ionization detector. Finally, the pressure effects on variation of CO and O_2 volume concentration were discussed. Considering the relatively small heat release rate for FPU foam selected, the CO concentration in the far-field ceiling jet low under low pressure was found to be lower for the enhanced diffusive effect.

Development, optimisation and application of polyurethane foams as new polymeric phases for stir bar sorptive extraction.

Science.gov (United States)

Neng, N R; Pinto, M L; Pires, J; Marcos, P M; Nogueira, J M F

2007-11-09

In this contribution, polyurethane foams are proposed as new polymeric phases for stir bar sorptive extraction (SBSE). Assays performed for polyurethane synthesis demonstrated that four series of formulations (P(1), P(2), P(3) and P(4)) present remarkable stability and excellent mechanical resistance to organic solvents. For polymer clean-up treatment, acetonitrile proved to be the best solvent under sonification, ensuring the reduction of the contamination and interferences. SBSE assays performed on these polyurethane polymers followed by liquid desorption and high-performance liquid chromatography-diode array detection (LD-HPLC-DAD) or large volume injection-capillary gas chromatography-mass spectrometry (LD-LVI-GC-MS), showed that P(2) presents the best recovery yields for atrazine, 2,3,4,5-tetrachlorophenol and fluorene, used as model compounds in water samples at a trace level. SBSE(P(2)) assays performed on this polymer mixed up with several adsorbent materials, i.e. activated carbon, a mesoporous material and a calixarene, did not bring any advantages in relation with the polymeric matrix alone. The comparison between assays performed by SBSE(P(2)) and by the conventional SBSE(PDMS) showed much better performance for the former phase on aqueous samples spiked with atrazine, 2,3,4,5-tetrachlorophenol and fluorene, in which the foremost two analytes present recovery values 3- and 10-fold higher, respectively. The polyurethanes proposed as new polymeric phases for SBSE provided powerful capabilities for the enrichment of organic compounds from aqueous matrices, showing to be indicated mainly in the case of the more polar analytes.

Effect of Rigid Polyurethane Foam Core Density on Flexural and Compressive Properties of Sandwich Panels with Glass/Epoxy Faces

Directory of Open Access Journals (Sweden)

saeed Nemati

2013-01-01

Full Text Available Sandwich panels as composite materials have two external walls of either metallic or polymer type. The space between these walls is filled by hard foam or other materials and the thickness of different layers is based on the final application of the panel. In the present work, the extent of variation in core density of polyether urethane foam and subsequent flexural and compressive changes in sandwich panels with glass or epoxy face sheets are tested and investigated. A number of hard polyether urethane foams with different middle panel layers density 80-295 kg/m3 are designed to study the effect of foam density on mechanical properties including flexural and compressive properties. Flexural and compressive test resultsshow that increased core density leads to improved mechanical properties. The slope of the curve decreases beyond density of 235 kg/m3. The reason may be explained on the limitation of shear intensity in increasing the mechanical properties. In this respect an optimum density of 235 kg/m3 is obtained for the system under examinations and for reaching higher strength panels, foams of different core materials should be selected.

Bio-based polyurethane composite foams with inorganic fillers studied by thermogravimetry

International Nuclear Information System (INIS)

Hatakeyema, Hyoe; Tanamachi, Noriko; Matsumura, Hiroshi; Hirose, Shigeo; Hatakeyama, Tatsuko

2005-01-01

Bio-based polyurethane (PU) composite foams filled with various inorganic fillers, such as barium sulfate (BaSO 4 ), calcium carbonate (CaCO 3 ) and talc were prepared using polyols, such as diethylene glycol, triethylene glycol and polyethylene glycol (molecular weight ca. 200) containing molasses and lignin. Reactive hydroxyl groups in plant components and above polyols were used as reaction sites. Morphological observation of fracture surface of composites was carried out by scanning electron microscopy. Thermal properties of bio-based PU composites were examined by thermogravimetry. It was found that the above composites decompose in two stages reflecting decomposition of organic components. Decomposition temperature increased with increasing filler content, when plant components were homogenously mixed with inorganic fillers. Activation energy calculated by Ozawa-Wall-Flynn method was ca. 150 kJ mol -1 . The durability of composites was predicted using kinetic data. Calculated values indicate that composites with fillers are more durable than that of those without fillers at a moderate temperature region

Grandstand view of phenolic foam insulation

Energy Technology Data Exchange (ETDEWEB)

1987-03-01

Stadium Insulation Ltd, manufacture pipe sections, tank and vessel insulation products in Lowphen, polyisocyanurate, polyurethane foams and expanded polystyrene, though for certain specialist applications, cork is still employed in small quantities. Currently the emphasis is very much on Lowphen, the company's range of pipe sections based on phenolic foam. The company's manufacturing and marketing effort reflects the increasing market trend towards the use of insulating material capable of withstanding higher temperatures, and phenolic foam neatly satisfies the demand since it is capable of use at temperatures up to 140/sup 0/C. Moreover, phenolic foam has the lowest K value at 0.02W/m/sup 0/C of any of the currently available range of insulating materials, and while the product is slightly more expensive than alternatives such as polyisocyanurate and polyurethane, its high performance offsets that premium.

Evaluation of Canisterized Foams and Evaluation of Radiation Hardened Foams for D&D Activities

Energy Technology Data Exchange (ETDEWEB)

Nicholson, J. C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-09-26

The introduction of polyurethane foams has previously been examined elsewhere within the DOE complex with regards to decontamination and decommissioning (D&D) activities, though its use has been prohibited as a result of excessive heat generation and flammability concerns per the safety basis. Should these foams be found compatible with respect to the facility safety basis requirements, D&D work involving large void containing structures such as gloveboxes could be eased through the fixation of residual contamination after decontamination efforts have concluded. To this end, SRNL embarked on a characterization of commercial epoxy foams to identify the characteristics that would be most important to safety basis requirements. Through SRNL’s efforts, the performance of commercial two-part epoxy foams was evaluated for their foaming characteristics, temperature profiles, loading capability with high-Z (high density) additives, and applicability for shielding gamma emission from isotopes including; Am-241, Cs-137, and Co-60. It was found that these foams are capable of encapsulation of a desired volume, though the ideal and experimental expansion coefficients were found to differ. While heat is generated during the reaction, no samples generated heat above 70 °C. Of the down–selected materials, heating was on the order of 40 °C for the flexible foam and 60 °C for the rigid foam. Both were found to return to room temperature after 20 minutes regardless of the volume of foam cast. It was also found that the direct introduction of high-Z additives were capable of attenuating 98% of Am-241 gamma signal, 16% of Cs-137 signal, and 9.5% of Co-60 signal at 1:1 loading capacities of total liquid constituent weight to additive weight. These efforts are currently being reviewed for the ASTM January 2017 subcommittee discussions to address the lack of test methods and standards regarding these materials with respect to D&D environments.

Center for the Polyurethanes Industry summary of unpublished industrial hygiene studies related to the evaluation of emissions of spray polyurethane foam insulation.

Science.gov (United States)

Wood, Richard D

2017-09-01

Spray polyurethane foam (SPF) insulation is used as thermal insulation for residential and commercial buildings. It has many advantages over other forms insulation; however, concerns have been raised related to chemical emissions during and after application. The American Chemistry Council's (ACC's) Center for the Polyurethanes Industry (CPI) has gathered previously unpublished industrial hygiene air sampling studies submitted by member companies that were completed during an eight-year period from 2007-2014. These studies address emissions from medium density closed cell and low density open cell formulations. This article summarizes the results of personal and area air samples collected during application and post application of SPF to interior building surfaces in both laboratory and field environments. Chemicals of interest included: Volatile Organic Compounds (VOCs), methylene diphenyl diisocyanate (MDI), flame retardants, amine catalysts, blowing agents, and aldehydes. Overall, the results indicate that SPF applicators and workers in close proximity to the application are potentially exposed to MDI in excess of recommended and governmental occupational exposure limits and should use personal protective equipment (PPE) consisting of air supplied respirators and full-body protective clothing to reduce exposure. Catalyst emissions can be reduced by using reactive catalysts in SPF formulations, and mechanical ventilation is important in controlling emissions during and after application.

Comparaison performantielle à court et à long termes de mortiers légers à base de déchets de mousse de polyuréthane rigide et de billes de polystyrène expansé Comparison of short and long-term performances of lightweight aggregate mortars made with polyurethane foam waste and expanded polystyrene beads

Directory of Open Access Journals (Sweden)

Mounanga P.

2012-09-01

Full Text Available Cet article s’intègre dans une étude menée sur la valorisation de déchets de mousse de polyuréthane rigide (PUR pour l’élaboration de matériaux cimentaires légers. Dans ce but, des mortiers ont été fabriqués en remplaçant partiellement le sable par des particules fines de mousse PUR. Les taux de remplacement volumique considérés sont de 25 et 50%. Afin de comparer les bénéfices apportés par l’utilisation de mousse PUR par rapport à des granulats légers commerciaux, des mortiers légers à base de billes de polystyrène expansé (PSE de diamètre compris entre 1,5 et 2,5 mm, ont également été fabriqués. L’ouvrabilité, la cinétique d’hydratation au jeune âge et les propriétés mécaniques (résistance à la compression et module d’Young dynamique, thermiques (conductivité thermique et capacité calorifique, le retrait de séchage et la perméabilité au gaz ont été mesurés sur les différents mortiers mis en oeuvre. Une analyse comparative de ces propriétés est alors proposée. This article is part of a study on the valorization of rigid polyurethane foam (PUR waste for the development of lightweight cementitious materials. Mortars were made with volume replacement rates of sand with plastic lightweight aggregates equal to 25 and 50%. To compare the benefits of the use of PUR foam in comparison with commercial lightweight aggregates, two types of aggregates were considered: PUR foam particles and expanded polystyrene beads. The workability, early-age hydration rate, mechanical properties (compressive strength and dynamic Young’s modulus, thermophysical properties (thermal conductivity and specific heat, drying shrinkage and gas permeability were measured on the different mortars investigated. A comparative analysis of these properties was then proposed, which showed that it was possible to produce lightweight aggregate mortars for structural use using PUR foam waste and that PUR foam particles had a

SORPTION OF Ga (III ON FLEXIBLE OPEN CELL POLYURETHANE FOAM OF POLYETHER TYPE IMPREGNATED WITH TRI-N-BUTHYL PHOSPATE

Directory of Open Access Journals (Sweden)

Lavinia Tofan

2007-06-01

Full Text Available The obtained results concerning the Ga (III ion retention on flexible open cell polyurethane foam of polyether type pretreated with tri-n-butyl phosphate are presented. The influence of solution acidity, phases contact time, Ga (III concentration and solution temperature have been investigated. The parameters of Ga (III batch sorption have been optimized. On the basis of Langmuir isotherms, the sorption constants and the thermodynamic parameters, ∆G, ∆Η and ∆S have been calculated.

Quantification of isocyanates and amines in polyurethane foams and coated products by liquid chromatography–tandem mass spectrometry

Science.gov (United States)

Mutsuga, Motoh; Yamaguchi, Miku; Kawamura, Yoko

2014-01-01

An analytical method for the identification and quantification of 10 different isocyanates and 11 different amines in polyurethane (PUR) foam and PUR-coated products was developed and optimized. Isocyanates were extracted and derivatized with di-n-butylamine, while amines were extracted with methanol. Quantification was subsequently performed by liquid chromatography–tandem mass spectrometry. Using this methodology, residual levels of isocyanates and amines in commercial PUR products were quantified. Although the recoveries of certain isocyanates and amines were low, the main compounds used as monomers in the production of PUR products, and their decomposition species, were clearly identified at quantifiable levels. 2,4-and 2,6-toluenediisocyanate were detected in most PUR foam samples and a pastry bag in the range of 0.02–0.92 mg/kg, with their decomposition compounds, 2,4-and 2,6-toluenediamine, detected in all PUR foam samples in the range of 9.5–59 mg/kg. PUR-coated gloves are manufactured using 4,4′-methylenebisphenyl diisocyanate as the main raw material, and a large amount of this compound, in addition to 4,4′-methylenedianiline and dicyclohexylmethane-4,4′-diamine were found in these samples. PMID:24804074

Polyurethane foam scaffold as in vitro model for breast cancer bone metastasis.

Science.gov (United States)

Angeloni, Valentina; Contessi, Nicola; De Marco, Cinzia; Bertoldi, Serena; Tanzi, Maria Cristina; Daidone, Maria Grazia; Farè, Silvia

2017-11-01

to recapitulate the development of metastases in different body sites but, still, the crucial challenge is to correctly mimic the tissue to be modelled in terms of physical, mechanical and biological properties. Here, we prove the suitability of a porous polyurethane foam, synthesized using an appropriate formulaton, in mimicking the bone tissue microenvironment and in reproducing the metastatic colonization derived from human breast cancer, particularly evidencing the devastating effects on the bone extracellular matrix caused by metastatic spreading. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Formation of layer-by-layer assembled titanate nanotubes filled coating on flexible polyurethane foam with improved flame retardant and smoke suppression properties.

Science.gov (United States)

Pan, Haifeng; Wang, Wei; Pan, Ying; Song, Lei; Hu, Yuan; Liew, Kim Meow

2015-01-14

A fire blocking coating made from chitosan, titanate nanotubes and alginate was deposited on a flexible polyurethane (FPU) foam surface by a layer-by-layer assembly technique in an effort to reduce its flammability. First, titanate nanotubes were prepared by a hydrothermal method. And then the coating growth was carried out by alternately submerging FPU foams into chitosan solution, titanate nanotubes suspension and alginate solution. The mass gain of coating on the surface of FPU foams showed dependency on the concentration of titanate nanotubes suspension and the trilayers's number. Scanning electron microscopy indicated that titanate nanotubes were distributed well on the entire surface of FPU foam and showed a randomly oriented and entangled network structure. The cone calorimeter result indicated that the coated FPU foams showed reduction in the peak heat release rate (peak HRR), peak smoke production rate (peak SPR), total smoke release (TSR) and peak carbon monoxide (CO) production compared with those of the control FPU foam. Especially for the FPU foam with only 5.65 wt % mass gain, great reduction in peak HRR (70.2%), peak SPR (62.8%), TSR (40.9%) and peak CO production (63.5%) could be observed. Such a significant improvement in flame retardancy and the smoke suppression property for FPU foam could be attributed to the protective effect of titanate nanotubes network structure formed, including insulating barrier effect and adsorption effect.

Startup and long-term performance of biotrickling filters packed with polyurethane foam and poplar wood chips treating a mixture of ethylmercaptan, H2S, and NH3.

Science.gov (United States)

Hernández, J; Lafuente, J; Prado, O J; Gabriel, D

2013-04-01

Treatment of a mixture of NH3, H2S, and ethylmercaptan (EM) was investigated for more than 15 months in two biotrickling filters packed with poplar wood chips and polyurethane foam. Inlet loads ranging from 5 to 10 g N-NH3 m-3 hr-1, from 5 to 16 g S-H2S m-3 hr-1, and from 0 to 5 g EM m-3 hr-1 were applied. During startup, the biotrickling filter packed with polyurethane foam was re-inoculated due to reduced biomass retention as well as a stronger effect of nitrogen compounds inhibition compared with the biotrickling filter packed with poplar wood. Accurate pH control between 7 and 7.5 favored pollutants abatement. In the long run, complete NH3 removal in the gas phase was achieved in both reactors, while H2S removal efficiencies exceeded 90%. EM abatement was significantly different in both reactors. A systematically lower elimination capacity was found in the polyurethane foam bioreactor. N fractions in the liquid phase proved that high nitrification rates were reached throughout steady-state operation in both bioreactors. CO2 production showed the extent of the organic packing material degradation, which allowed estimating its service lifetime in around 2 years. In the long run, the bioreactor packed with the organic packing material had a lower stability. However, an economic analysis indicated that poplar wood chips are a competitive alternative to inorganic packing materials in biotrickling filters. We provide new insights in the use of organic packing materials in biotrickling filters for the treatment of H2S, NH3, and mercaptans and compare them with polyurethane foam, a packing commonly used in biotrickling filters. We found interesting features related with the startup of the reactors and parameterized both the performance under steady-state conditions and the influence of the gas contact time. We provide relevant conclusions in the profitability of organic packing materials under a biotrickling filter configuration, which is infrequent but proven reliable

Fire-Induced Response in Foam Encapsulants

Energy Technology Data Exchange (ETDEWEB)

Borek, T.T.; Chu, T.Y.; Erickson, K.L.; Gill, W.; Hobbs, M.L.; Humphries, L.L.; Renlund, A.M.; Ulibarri, T.A.

1999-04-02

The paper provides a concise overview of a coordinated experimental/theoretical/numerical program at Sandia National Laboratories to develop an experimentally validated model of fire-induced response of foam-filled engineered systems for nuclear and transportation safety applications. Integral experiments are performed to investigate the thermal response of polyurethane foam-filled systems exposed to fire-like heat fluxes. A suite of laboratory experiments is performed to characterize the decomposition chemistry of polyurethane. Mass loss and energy associated with foam decomposition and chemical structures of the virgin and decomposed foam are determined. Decomposition chemistry is modeled as the degradation of macromolecular structures by bond breaking followed by vaporization of small fragments of the macromolecule with high vapor pressures. The chemical decomposition model is validated against the laboratory data. Data from integral experiments is used to assess and validate a FEM foam thermal response model with the chemistry model developed from the decomposition experiments. Good agreement was achieved both in the progression of the decomposition front and the in-depth thermal response.

Stress wave propagation and mitigation in two polymeric foams

Science.gov (United States)

Pradel, Pierre; Malaise, Frederic; Cadilhon, Baptiste; Quessada, Jean-Hugues; de Resseguier, Thibaut; Delhomme, Catherine; Le Blanc, Gael

2017-06-01

Polymeric foams are widely used in industry for thermal insulation or shock mitigation. This paper investigates the ability of a syntactic epoxy foam and an expanded polyurethane foam to mitigate intense (several GPa) and short duration (<10-6 s) stress pulses. Plate impact and electron beam irradiation experiments have been conducted to study the dynamic mechanical responses of both foams. Interferometer Doppler Laser method is used to record the target rear surface velocity. A two-wave structure associated with the propagation of an elastic precursor followed by the compaction of the pores has been observed. The compaction stress level deduced from the velocity measurement is a good indicator of mitigation capability of the foams. Quasi-static tests and dynamic soft recovery experiments have also been performed to determine the compaction mechanisms. In the polyurethane foam, the pores are closed by elastic buckling of the matrix and damage of the structure. In the epoxy foam, the compaction is due to the crushing of glass microspheres. Two porous material models successfully represent the macroscopic response of these polymeric foams.

Determination of aromatic amines in aqueous extracts of polyurethane foam using hydrophilic interaction liquid chromatography and mass spectrometry

International Nuclear Information System (INIS)

Riddar Johnson, Jakob; Karlsson, Daniel; Dalene, Marianne; Skarping, Gunnar

2010-01-01

A method is presented for the determination of aromatic amines in aqueous extracts of polyurethane (PUR) foam. The method is based on the extraction of PUR foam using aqueous acetic acid (0.1%, w/v) followed by determination of extracted aromatic amines using hydrophilic interaction liquid chromatography (HILIC) and tandem mass spectrometry (MS/MS) with positive electrospray ionisation. The injections of volumes up to 5 μL of aqueous solutions were made possible by on-column focusing with partially filled loop injections. The fragmentation patterns for 2,4- and 2,6-toluene diamine (TDA) and 4,4'-methylene dianiline (MDA) were clarified by performing a hydrogen-deuterium exchange study. TDA and MDA were determined using trideuterated 2,4- and 2,6-TDA and dideuterated 4,4'-MDA as internal standards. Linear calibration graphs were obtained over the range 0.025-0.5 μg mL -1 with correlation coefficients >0.996 and the instrumental detection limit for each compound was <50 fmol. The stability of the amines was influenced by the matrix, so their concentrations decreased over time. Agreement was observed between the results of analyses of PUR foam extracts by HILIC-MS/MS and results obtained by ethyl chloroformate derivatisation and reversed phase (RP) liquid chromatography-mass spectrometry (LC-MS/MS). TDA was observed to be unstable in extracts of foam but not in pure solutions.

A Simple Approach to Distinguish Classic and Formaldehyde-Free Tannin Based Rigid Foams by ATR FT-IR

Directory of Open Access Journals (Sweden)

Gianluca Tondi

2015-01-01

Full Text Available Tannin based rigid foams (TBRFs have been produced with formaldehyde since 1994. Only recently several methods have been developed in order to produce these foams without using formaldehyde. TBRFs with and without formaldehyde are visually indistinguishable; therefore a method for determining the differences between these foams had to be found. The attenuated total reflectance infrared spectroscopy (ATR FT-IR investigation of the TBRFs presented in this paper allowed discrimination between the formaldehyde-containing (classic and formaldehyde-free TBRFs. The spectra of the formaldehyde-free TBRFs, indeed, present decreased band intensity related to the C–O stretching vibration of (i the methylol groups and (ii the furanic rings. This evidence served to prove the chemical difference between the two TBRFs and explained the slightly higher mechanical properties measured for the classic TBRFs.

An approach to model validation and model-based prediction -- polyurethane foam case study.

Energy Technology Data Exchange (ETDEWEB)

Dowding, Kevin J.; Rutherford, Brian Milne

2003-07-01

Enhanced software methodology and improved computing hardware have advanced the state of simulation technology to a point where large physics-based codes can be a major contributor in many systems analyses. This shift toward the use of computational methods has brought with it new research challenges in a number of areas including characterization of uncertainty, model validation, and the analysis of computer output. It is these challenges that have motivated the work described in this report. Approaches to and methods for model validation and (model-based) prediction have been developed recently in the engineering, mathematics and statistical literatures. In this report we have provided a fairly detailed account of one approach to model validation and prediction applied to an analysis investigating thermal decomposition of polyurethane foam. A model simulates the evolution of the foam in a high temperature environment as it transforms from a solid to a gas phase. The available modeling and experimental results serve as data for a case study focusing our model validation and prediction developmental efforts on this specific thermal application. We discuss several elements of the ''philosophy'' behind the validation and prediction approach: (1) We view the validation process as an activity applying to the use of a specific computational model for a specific application. We do acknowledge, however, that an important part of the overall development of a computational simulation initiative is the feedback provided to model developers and analysts associated with the application. (2) We utilize information obtained for the calibration of model parameters to estimate the parameters and quantify uncertainty in the estimates. We rely, however, on validation data (or data from similar analyses) to measure the variability that contributes to the uncertainty in predictions for specific systems or units (unit-to-unit variability). (3) We perform statistical

A single α-cobalt hydroxide/sodium alginate bilayer layer-by-layer assembly for conferring flame retardancy to flexible polyurethane foams

Energy Technology Data Exchange (ETDEWEB)

Mu, Xiaowei [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026 (China); Yuan, Bihe [School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan 430070 (China); Pan, Ying; Feng, Xiaming; Duan, Lijin [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026 (China); Zong, Ruowen, E-mail: zongrw@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026 (China); National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230026 (China)

2017-04-15

A layer-by-layer (LBL) assembly coating composed of α-cobalt hydroxide (α-Co(OH){sub 2}) and sodium alginate (SA) is deposited on flexible polyurethane (FPU) foam to reduce its flammability. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) are employed to prove the LBL assembly process. It is obvious from SEM results that a uniform and rough coating is deposited on FPU foam compared with that of untreated one. The peak intensity of methylene of SA in FITR spectra and typical (003) diffraction peak of α-Co(OH){sub 2} nanosheets at 11.0° in XRD patterns increases gradually with increment of bilayer number. Combustion behavior and toxicity suppression property of samples are characterized by cone calorimeter (under an irradiance of 35 kW m{sup −2}) and Thermogravimetry/Fourier transform infrared spectroscopy. The one and two bilayers (BL) coating on FPU foam can achieve excellent flame retardancy. Compared with untreated sample, the peak heat release rate of the coated FPU foam containing only one BL coating is reduced by 58.7%. The content of gaseous toxic substances during pyrolysis of FPU foam deposited with a single bilayer coating, such as CO and NCO-containing compounds, are reduced by 20.0% and 9.2%, respectively. Besides, the flame retardant mechanism of the coated FPU foam is also revealed. - Highlights: • The α-Co(OH){sub 2} nanosheets are firstly employed in LBL assembly. • A single α-cobalt hydroxide/sodium alginate bilayer LBL assembly for conferring excellent flame retardancy to FPU foam. • The flame retardant mechanism of LBL assembly FPU foam is displayed.

Investigation of the pressure generated in the mould cavity during polyurethane integral skin foam moulding

Directory of Open Access Journals (Sweden)

2008-07-01

Full Text Available An industrial scale measuring system was set up to investigate the pressure arising in the mould cavity during polyurethane integral skin foaming. The system is able to measure the pressure arising in the mould cavity and the pressure distribution using a piezoresistive pressure sensor. The pressure distribution was measured at 18 points along the mould surface at constant production parameters. Then six production parameters, which affect the pressure, were investigated in detail with the Taguchi method of experimental design. The results of the design were processed by ANOVA (analysis of variance. Three major influencing parameters were estimated by regression analysis. Finally an equation was developed to give a good estimation to the pressure arising in the mould cavity.

Design and milling manufacture of polyurethane custom contoured cushions for wheelchair users.

Science.gov (United States)

da Silva, Fabio Pinto; Beretta, Elisa Marangon; Prestes, Rafael Cavalli; Kindlein Junior, Wilson

2011-01-01

The design of custom contoured cushions manufactured in flexible polyurethane foams is an option to improve positioning and comfort for people with disabilities that spend most of the day seated in the same position. These surfaces increase the contact area between the seat and the user. This fact contributes to minimise the local pressures that can generate problems like decubitus ulcers. The present research aims at establishing development routes for custom cushion production to wheelchair users. This study also contributes to the investigation of Computer Numerical Control (CNC) machining of flexible polyurethane foams. The proposed route to obtain the customised seat began with acquiring the user's contour in adequate posture through plaster cast. To collect the surface geometry, the cast was three-dimensionally scanned and manipulated in CAD/CAM software. CNC milling parameters such as tools, spindle speeds and feed rates to machine flexible polyurethane foams were tested. These parameters were analysed regarding the surface quality. The best parameters were then tested in a customised seat. The possible dimensional changes generated during foam cutting were analysed through 3D scanning. Also, the customised seat pressure and temperature distribution was tested. The best parameters found for foams with a density of 50kg/cm(3) were high spindle speeds (24000 rpm) and feed rates between 2400-4000mm/min. Those parameters did not generate significant deformities in the machined cushions. The custom contoured cushion satisfactorily increased the contact area between wheelchair and user, as it distributed pressure and heat evenly. Through this study it was possible to define routes for the development and manufacturing of customised seats using direct CNC milling in flexible polyurethane foams. It also showed that custom contoured cushions efficiently distribute pressure and temperature, which is believed to minimise tissue lesions such as pressure ulcers.

Self-Calibrating, Variable-Flow Pumping System

Science.gov (United States)

Walls, Joe T.

1994-01-01

Pumping system provides accurate, controlled flows of two chemical liquids mixed in spray head and react to form rigid or flexible polyurethane or polyisocyanurate foam. Compatible with currently used polyurethane-based coating materials and gas-bubble-forming agents (called "blowing agents" in industry) and expected to be compatible with materials that used in near future. Handles environmentally acceptable substitutes for chlorofluorocarbon foaming agents.

Synthesis of α-Fe₂O₃ and Fe-Mn Oxide Foams with Highly Tunable Magnetic Properties by the Replication Method from Polyurethane Templates.

Science.gov (United States)

Feng, Yuping; Fornell, Jordina; Zhang, Huiyan; Solsona, Pau; Barό, Maria Dolors; Suriñach, Santiago; Pellicer, Eva; Sort, Jordi

2018-02-11

Open cell foams consisting of Fe and Fe-Mn oxides are prepared from metallic Fe and Mn powder precursors by the replication method using porous polyurethane (PU) templates. First, reticulated PU templates are coated by slurry impregnation. The templates are then thermally removed at 260 °C and the debinded powders are sintered at 1000 °C under N₂ atmosphere. The morphology, structure, and magnetic properties are studied by scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry, respectively. The obtained Fe and Fe-Mn oxide foams possess both high surface area and homogeneous open-cell structure. Hematite (α-Fe₂O₃) foams are obtained from the metallic iron slurry independently of the N₂ flow. In contrast, the microstructure of the FeMn-based oxide foams can be tailored by adjusting the N₂ flow. While the main phases for a N₂ flow rate of 180 L/h are α-Fe₂O₃ and FeMnO₃, the predominant phase for high N₂ flow rates (e.g., 650 L/h) is Fe₂MnO₄. Accordingly, a linear magnetization versus field behavior is observed for the hematite foams, while clear hysteresis loops are obtained for the Fe₂MnO₄ foams. Actually, the saturation magnetization of the foams containing Mn increases from 5 emu/g to 52 emu/g when the N₂ flow rate (i.e., the amount of Fe₂MnO₄) is increased. The obtained foams are appealing for a wide range of applications, such as electromagnetic absorbers, catalysts supports, thermal and acoustic insulation systems or wirelessly magnetically-guided porous objects in fluids.

Preconcentration of traces of radionuclides with sorbents based on spherical polyurethane membrane systems in the analysis of environmental samples

International Nuclear Information System (INIS)

Palagyi, S.; Braun, T.

1986-01-01

In the paper the importance of preconcentration and a permanent need for efficient preconcentrating agents in environmental analysis are pointed out. The increased attention is devoted to the foamed polyurethane sorbents as a novel advance in the separation chemistry. The paper has two main aims. The first is to present a survey of recent applications of unloaded and reagent loaded open-cell type resilient polyurethane foams to the separation and preconcentration of radionuclides from environmental samples. The second is to show the newest results in the use of these foams for the preconcentration and determination of traces of some mainly inorganic species in environmental samples by radioanalytical techniques. Some future possibilities of the use of polyurethane foams in trace elemental determinations in environmental analysis are also outlined. (author)

Physicochemical characterization of chitosan/nylon6/polyurethane foam chemically cross-linked ternary blends.

Science.gov (United States)

Jayakumar, S; Sudha, P N

2013-03-15

Chitosan/nylon6/polyurethane foam (CS/Ny6/PUF) ternary blend was prepared and chemically cross-linked with glutaraldehyde. Structural, thermal and morphological studies were performed for the prepared ternary blends. Characterizations of the ternary blends were investigated by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM). The FTIR results showed that the strong intermolecular hydrogen bonds took place between CS, Ny6 and PUF. TGA and DSC studies reveal that the thermal stability of the blend is enhanced by glutaraldehyde as crosslinking agent. Results of XRD indicated that the relative crystalline of pure CS film was reduced when the polymeric network was reticulated by glutaraldehyde. Finally, the results of scanning electron microscopy (SEM) indicated that the morphology of the blend is rough and heterogeneous, further it confirms the interaction between the functional groups of the blend components. Copyright © 2012 Elsevier B.V. All rights reserved.

The use of silica gel prepared by sol-gel method and polyurethane foam as microbial carriers in the continuous degradation of phenol.

Science.gov (United States)

Brányik, T; Kuncová, G; Páca, J

2000-08-01

A mixed microbial culture was immobilized by entrapment into silica gel (SG) and entrapment/ adsorption on polyurethane foam (PU) and ceramic foam. The phenol degradation performance of the SG biocatalyst was studied in a packed-bed reactor (PBR), packed-bed reactor with ceramic foam (PBRC) and fluidized-bed reactor (FBR). In continuous experiments the maximum degradation rate of phenol (q(s)max) decreased in the order: PBRC (598 mg l(-1) h(-1)) > PBR (PU, 471 mg l(-1)h(-1)) > PBR(SG, 394 mg l(-1) h(-1)) > FBR (PU, 161 mg l(-1) h(-1)) > FBR (SG, 91 mg l(-1) h(-1)). The long-term use of the SG biocatalyst in continuous phenol degradation resulted in the formation of a 100-200 microm thick layer with a high cell density on the surface of the gel particles. The abrasion of the surface layer in the FBR contributed to the poor degradation performance of this reactor configuration. Coating the ceramic foam with a layer of cells immobilized in colloidal SiO2 enhanced the phenol degradation efficiency during the first 3 days of the PBRC operation, in comparison with untreated ceramic packing.

Multiple-Nozzle Spray Head Applies Foam Insulation

Science.gov (United States)

Walls, Joe T.

1993-01-01

Spray head equipped with four-nozzle turret mixes two reactive components of polyurethane and polyisocyanurate foam insulating material and sprays reacting mixture onto surface to be insulated. If nozzle in use becomes clogged, fresh one automatically rotated into position, with minimal interruption of spraying process. Incorporates features recirculating and controlling pressures of reactive components to maintain quality of foam by ensuring proper blend at outset. Also used to spray protective coats on or in ships, aircraft, and pipelines. Sprays such reactive adhesives as epoxy/polyurethane mixtures. Components of spray contain solid-particle fillers for strength, fire retardance, toughness, resistance to abrasion, or radar absorption.

Lipid for biodiesel production from attached growth Chlorella vulgaris biomass cultivating in fluidized bed bioreactor packed with polyurethane foam material.

Science.gov (United States)

Mohd-Sahib, Ainur-Assyakirin; Lim, Jun-Wei; Lam, Man-Kee; Uemura, Yoshimitsu; Isa, Mohamed Hasnain; Ho, Chii-Dong; Kutty, Shamsul Rahman Mohamed; Wong, Chung-Yiin; Rosli, Siti-Suhailah

2017-09-01

The potential to grow attached microalgae Chlorella vulgaris in fluidized bed bioreactor was materialized in this study, targeting to ease the harvesting process prior to biodiesel production. The proposed thermodynamic mechanism and physical property assessment of various support materials verified polyurethane to be suitable material favouring the spontaneous adhesion by microalgae cells. The 1-L bioreactor packed with only 2.4% (v/v) of 1.00-mL polyurethane foam cubes could achieve the highest attached growth microalgae biomass and lipid weights of 812±122 and 376±37mg, respectively, in comparison with other cube sizes. The maturity of attached growth microalgae biomass for harvesting could also be determined from the growth trend of suspended microalgae biomass. Analysis of FAME composition revealed that the harvested microalgae biomass was dominated by C16-C18 (>60%) and mixture of saturated and mono-unsaturated fatty acids (>65%), satiating the biodiesel standard with adequate cold flow property and oxidative stability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Separation of uranium by extraction with foamed plastics

International Nuclear Information System (INIS)

Korkisch, J.

1983-07-01

Polyurethane foams are frequently used for the extraction and separation of inorganic and organic species. The attraction of the materials lies in their favourable hydrodynamic properties obviating the need for the forced-flow conditions associated with conventional chromatographic-type column packing of small particles. The research work described has been directed to providing information on the extraction and separation of uranium (and thorium) by an open-cell polyurethane foam from media containing nitrates and from hydrochloric acid systems. The influence of many different experimental parameters (concentrations, acidity, impregnation of the foam with organic extractants) on the extraction was investigated. Based on the results of these investigations two methods were developed to separate uranium from nitric acid solution and from hydrochloric acid solution, respectively. The first uses calcium or aluminium nitrate salting and foam impregnated with Aliquat 336, the second ascorbic acid addition and TOPO-impregnated foam. The methods separate uranium and thorium from each other and from most other elements and can be used analytically or in the purification of uranium from impure plant products such as yellow cake

H1259 Container Foams: Performance Data on Aged Materials

International Nuclear Information System (INIS)

Linda Domeier

2002-01-01

Samples of the three cushioning foams used in the H1259 weapon storage container were obtained in 1997, 1998, 2000 and 2001 and tested for density, compression set and compressive strength using the same procedures specified for acceptance testing. Foams from six containers, all about 30 years old and located at Pantex, were evaluated. The bottom cushioning foam is a General Plastics polyurethane foam and the two side pads are rebonded polyurethane foams. All the tests were carried out at room temperature. When compared to the original acceptance requirements the foams were generally in-spec for density and compressive strength at 10% strain and were generally out-of-spec for compression set and compressive strength at 50% strain. Significant variability was noted in the performance of each foam sample and even more in the container-to-container foam performance. The container-to-container variability remains the major unknown in predicting the long-term suitability of these containers for continued use. The performance of the critical bottom cushion foams was generally more uniform and closer to the specified performance than that of the rebonded foams. It was judged that all the foams were adequate for continued use as storage container foams (not shipping) under controlled conditions to mitigate temperature extremes or high impact. This archived information is important in evaluations of the continued suitability for weapon storage use of the H1259 containers and other containers using the same foam cushions

Auxetic Foam-Based Contact-Mode Triboelectric Nanogenerator with Highly Sensitive Self-Powered Strain Sensing Capabilities to Monitor Human Body Movement

KAUST Repository

Zhang, Steven L.; Lai, Ying-Chih; He, Xu; Liu, Ruiyuan; Zi, Yunlong; Wang, Zhong Lin

2017-01-01

The first contact-mode triboelectric self-powered strain sensor using an auxetic polyurethane foam, conductive fabric, and polytetrafluroethylene (PTFE) is fabricated. Utilizing the auxetic properties of the polyurethane foam, the auxetic polyurethane foam would expand into the PTFE when the foam is stretched, causing contact electrification. Due to a larger contact area between the PTFE and the foam as the foam is stretched, this device can serve effectively as a strain sensor. The sensitivity of this method is explored, and this sensor has the highest sensitivity in all triboelectric nanogenerator devices that are used previously as a strain sensor. Different applications of this strain sensor are shown, and this sensor can be used as a human body monitoring system, self-powered scale to measure weight, and a seat belt to measure body movements inside a car seat.

Auxetic Foam-Based Contact-Mode Triboelectric Nanogenerator with Highly Sensitive Self-Powered Strain Sensing Capabilities to Monitor Human Body Movement

KAUST Repository

Zhang, Steven L.

2017-05-15

The first contact-mode triboelectric self-powered strain sensor using an auxetic polyurethane foam, conductive fabric, and polytetrafluroethylene (PTFE) is fabricated. Utilizing the auxetic properties of the polyurethane foam, the auxetic polyurethane foam would expand into the PTFE when the foam is stretched, causing contact electrification. Due to a larger contact area between the PTFE and the foam as the foam is stretched, this device can serve effectively as a strain sensor. The sensitivity of this method is explored, and this sensor has the highest sensitivity in all triboelectric nanogenerator devices that are used previously as a strain sensor. Different applications of this strain sensor are shown, and this sensor can be used as a human body monitoring system, self-powered scale to measure weight, and a seat belt to measure body movements inside a car seat.

Normalized inverse characterization of sound absorbing rigid porous media.

Science.gov (United States)

Zieliński, Tomasz G

2015-06-01

This paper presents a methodology for the inverse characterization of sound absorbing rigid porous media, based on standard measurements of the surface acoustic impedance of a porous sample. The model parameters need to be normalized to have a robust identification procedure which fits the model-predicted impedance curves with the measured ones. Such a normalization provides a substitute set of dimensionless (normalized) parameters unambiguously related to the original model parameters. Moreover, two scaling frequencies are introduced, however, they are not additional parameters and for different, yet reasonable, assumptions of their values, the identification procedure should eventually lead to the same solution. The proposed identification technique uses measured and computed impedance curves for a porous sample not only in the standard configuration, that is, set to the rigid termination piston in an impedance tube, but also with air gaps of known thicknesses between the sample and the piston. Therefore, all necessary analytical formulas for sound propagation in double-layered media are provided. The methodology is illustrated by one numerical test and by two examples based on the experimental measurements of the acoustic impedance and absorption of porous ceramic samples of different thicknesses and a sample of polyurethane foam.

"Grinding" cavities in polyurethane foam

Science.gov (United States)

Brower, J. R.; Davey, R. E.; Dixon, W. F.; Robb, P. H.; Zebus, P. P.

1980-01-01

Grinding tool installed on conventional milling machine cuts precise cavities in foam blocks. Method is well suited for prototype or midsize production runs and can be adapted to computer control for mass production. Method saves time and materials compared to bonding or hot wire techniques.

Rapid hemostatic and mild polyurethane-urea foam wound dressing for promoting wound healing

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiangyu; Niu, Yuqing [College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060 (China); Nanshan District Key lab for Biopolymers and Safety Evaluation, Shenzhen 518060 (China); Shenzhen Key Laboratory of Polymer Science and Technology, Shenzhen 518060 (China); Guangdong Research Center for Interfacial Engineering of Functional Materials, Shenzhen 518060 (China); Chen, Kevin C. [Multidisciplinary Research Center, Shantou University, Shantou, Guangdong 515063 (China); Chen, Shiguo, E-mail: csg@szu.edu.cn [College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060 (China); Nanshan District Key lab for Biopolymers and Safety Evaluation, Shenzhen 518060 (China); Shenzhen Key Laboratory of Polymer Science and Technology, Shenzhen 518060 (China); Guangdong Research Center for Interfacial Engineering of Functional Materials, Shenzhen 518060 (China)

2017-02-01

A novel rapid hemostatic and mild polyurethane-urea foam (PUUF) wound dressing was prepared by the particle leaching method and vacuum freeze-drying method using 4, 4-Methylenebis(cyclohexyl isocyanate), 4,4-diaminodicyclohexylmethane and poly (ethylene glycol) as raw materials. And X-ray diffraction (XRD), tensile test, differential scanning calorimetry (DSC) and thermogravimetry (TG) were used to its crystallinity, stress and strain behavior, and thermal properties, respectively. Platelet adhesion, fibrinogen adhesion and blood clotting were performed to evaluate its hemostatic effect. And H&E staining and Masson Trichrome staining were used to its wound healing efficacy. The results revealed the pore size of PUUF is 50–130 μm, and its porosity is 71.01%. Porous PUUF exhibited good water uptake that was benefit to adsorb abundant wound exudates to build a regional moist environment beneficial for wound healing. The PUUF wound dressing exhibit better blood coagulation effect than commercial polyurethane dressing (CaduMedi). Though both PUUF and CaduMedi facilitated wound healing generating full re-epithelialization within 13 days, PUUF was milder and lead to more slight inflammatory response than CaduMedi. In addition, PUUF wound dressing exhibited lower cytotoxicity than CaduMedi against NIH3T3 cells. Overall, porous PUUF represents a novel mild wound dressing with excellent water uptake, hemostatic effect and low toxicity, and it can promote wound healing and enhance re-epithelialization. - Highlights: • Rapid hemostatic and mild PUUF wound dressing was fabricated. • Low-toxic PUUF exhibited good water uptake that could build a regional moist environment beneficial for wound healing. • PUUF could promote wound healing and enhance re-epithelialization.

System Acquires Data On Reactivities Of Foams

Science.gov (United States)

Walls, Joe T.

1994-01-01

Data-acquisition and -plotting system, called DAPS(TM), developed enabling accurate and objective determination of physical properties related to reactivities of polyurethane and polyisocyanurate foams. Automated, computer-controlled test apparatus that acquires data on rates of rise, rise profiles, exothermic temperatures, and internal pressures of foams prepared from both manual and machine-mixed batches. Data used to determine minute differences between reaction kinetics and exothermic profiles of foam formulations, properties of end products which are statistically undifferentiated.

An Experimental Comparison Between Flexible and Rigid Airfoils at Low Reynolds Numbers

Science.gov (United States)

Uzodinma, Jaylon; Macphee, David

2017-11-01

This study uses experimental and computational research methods to compare the aerodynamic performance of rigid and flexible airfoils at a low Reynolds number throughout varying angles of attack. This research can be used to improve the design of small wind turbines, micro-aerial vehicles, and any other devices that operate at low Reynolds numbers. Experimental testing was conducted in the University of Alabama's low-speed wind tunnel, and computational testing was conducted using the open-source CFD code OpenFOAM. For experimental testing, polyurethane-based (rigid) airfoils and silicone-based (flexible) airfoils were constructed using acrylic molds for NACA 0012 and NACA 2412 airfoil profiles. Computer models of the previously-specified airfoils were also created for a computational analysis. Both experimental and computational data were analyzed to examine the critical angles of attack, the lift and drag coefficients, and the occurrence of laminar boundary separation for each airfoil. Moreover, the computational simulations were used to examine the resulting flow fields, in order to provide possible explanations for the aerodynamic performances of each airfoil type. EEC 1659710.

Estimation of the Human Extrathoracic Deposition Fraction of Inhaled Particles Using a Polyurethane Foam Collection Substrate in an IOM Sampler

Directory of Open Access Journals (Sweden)

Darrah K. Sleeth

2016-03-01

Full Text Available Extrathoracic deposition of inhaled particles (i.e., in the head and throat is an important exposure route for many hazardous materials. Current best practices for exposure assessment of aerosols in the workplace involve particle size selective sampling methods based on particle penetration into the human respiratory tract (i.e., inhalable or respirable sampling. However, the International Organization for Standardization (ISO has recently adopted particle deposition sampling conventions (ISO 13138, including conventions for extrathoracic (ET deposition into the anterior nasal passage (ET1 and the posterior nasal and oral passages (ET2. For this study, polyurethane foam was used as a collection substrate inside an inhalable aerosol sampler to provide an estimate of extrathoracic particle deposition. Aerosols of fused aluminum oxide (five sizes, 4.9 µm–44.3 µm were used as a test dust in a low speed (0.2 m/s wind tunnel. Samplers were placed on a rotating mannequin inside the wind tunnel to simulate orientation-averaged personal sampling. Collection efficiency data for the foam insert matched well to the extrathoracic deposition convention for the particle sizes tested. The concept of using a foam insert to match a particle deposition sampling convention was explored in this study and shows promise for future use as a sampling device.

Estimation of the Human Extrathoracic Deposition Fraction of Inhaled Particles Using a Polyurethane Foam Collection Substrate in an IOM Sampler.

Science.gov (United States)

Sleeth, Darrah K; Balthaser, Susan A; Collingwood, Scott; Larson, Rodney R

2016-03-07

Extrathoracic deposition of inhaled particles (i.e., in the head and throat) is an important exposure route for many hazardous materials. Current best practices for exposure assessment of aerosols in the workplace involve particle size selective sampling methods based on particle penetration into the human respiratory tract (i.e., inhalable or respirable sampling). However, the International Organization for Standardization (ISO) has recently adopted particle deposition sampling conventions (ISO 13138), including conventions for extrathoracic (ET) deposition into the anterior nasal passage (ET₁) and the posterior nasal and oral passages (ET₂). For this study, polyurethane foam was used as a collection substrate inside an inhalable aerosol sampler to provide an estimate of extrathoracic particle deposition. Aerosols of fused aluminum oxide (five sizes, 4.9 µm-44.3 µm) were used as a test dust in a low speed (0.2 m/s) wind tunnel. Samplers were placed on a rotating mannequin inside the wind tunnel to simulate orientation-averaged personal sampling. Collection efficiency data for the foam insert matched well to the extrathoracic deposition convention for the particle sizes tested. The concept of using a foam insert to match a particle deposition sampling convention was explored in this study and shows promise for future use as a sampling device.

Separation and determination of trace amounts of zinc, lead, cadmium and mercury in tap and Qaroun lake water using polyurethane foam functionalized with 4-hydroxytoluene and 4-hydroxyacetophenone

International Nuclear Information System (INIS)

Burham, N.; Abdel-Azeem, S.M.; El-Shahat, M.F.

2006-01-01

A stable chelating sorbent was synthesized by covalently linking 4-hydroxytoluene or 4-hydroxyacetophenone with the polyurethane foam (PUF) through -N=N- group. The synthesized chelating sorbents were characterized by IR and UV/vis measurements. The modified foams show excellent stability towards various solvents. Factors influencing the extraction process of Zn(II), Pb(II), Cd(II) and Hg(II) were studied and evaluated as a function of pH of metal ion solution and equilibration shaking time. The values of sorption capacity of metal ions (μg g -1 ) were determined with the two types of bonded foams. The two phenolic bonded foams were studied comparatively. The potential applications of the two newly synthesized foams for the removal and separation of the examined metal ions from two natural water samples (drinking tap water and Qaroun lake water at Fayoum City, Egypt) were investigated. Precision (assessed as a relative standard deviation, R.S.D.) was also evaluated and found to be ≤7.3% (N = 5) with a detection limit under 0.46 μg L -1

Separation and determination of trace amounts of zinc, lead, cadmium and mercury in tap and Qaroun lake water using polyurethane foam functionalized with 4-hydroxytoluene and 4-hydroxyacetophenone

Energy Technology Data Exchange (ETDEWEB)

Burham, N. [Chemistry Department, Faculty of Science, Fayoum University, Fayoum City (Egypt)]. E-mail: n_burham@yahoo.com; Abdel-Azeem, S.M. [Chemistry Department, Faculty of Science, Fayoum University, Fayoum City (Egypt); El-Shahat, M.F. [Chemistry Department, Faculty of Science, Ain-Shams University, Cairo (Egypt)

2006-10-10

A stable chelating sorbent was synthesized by covalently linking 4-hydroxytoluene or 4-hydroxyacetophenone with the polyurethane foam (PUF) through -N=N- group. The synthesized chelating sorbents were characterized by IR and UV/vis measurements. The modified foams show excellent stability towards various solvents. Factors influencing the extraction process of Zn(II), Pb(II), Cd(II) and Hg(II) were studied and evaluated as a function of pH of metal ion solution and equilibration shaking time. The values of sorption capacity of metal ions ({mu}g g{sup -1}) were determined with the two types of bonded foams. The two phenolic bonded foams were studied comparatively. The potential applications of the two newly synthesized foams for the removal and separation of the examined metal ions from two natural water samples (drinking tap water and Qaroun lake water at Fayoum City, Egypt) were investigated. Precision (assessed as a relative standard deviation, R.S.D.) was also evaluated and found to be {<=}7.3% (N = 5) with a detection limit under 0.46 {mu}g L{sup -1}.

Síntesis de espumas rígidas de poliuretano obtenidas a partir de aceite de castor y poliglicerol empleando calentamiento por microondas Synthesis of rigid polyurethane foams obtained from castor oil and polyglycerol using microwave heating

Directory of Open Access Journals (Sweden)

Paula Mazo

2011-01-01

Full Text Available En este trabajo se realizó la síntesis de espumas rígidas de poliuretano utilizando un macropoliol sintetizado a partir de aceite de castor y poliglicerol, se optimizó mediante un análisis de superficie de respuesta, empleando un diseño factorial 32, los factores evaluados fueron: cantidad de agua y de ácido tartárico, el cual actúa como agente entrecruzante y catalizador; se evalúaron las propiedades mecánicas de las espumas como: densidad aparente (ASTM D1622-08, resistencia a la compresión (ASTM D1621, conductividad térmica (ASTM C177-04 y friabilidad (ASTM C421-8; se realizó Microscopia Electrónica de Barrido (SEM y Análisis de Calorimetría Diferencial de Barrido (DSC. El macropoliol fue obtenido desde fuentes renovables, mediante la transesterificación de Aceite de Castor (CO ó Aceite de Castor Maleinizado (MACO con Poliglicerol (PG. Se evalúo el efecto de las microondas en las reacciones, donde se encuentra una disminución del tiempo; el seguimiento y la caracterización de los productos intermedios se realiza mediante la cuantificación de valor ácido por titulación (ASTM D4662-03 y número de hidroxilos (ASTM D4274-05.In this work we showed the polyurethane rigid foams synthesis using a macropolyol synthesized from castor oil and polyglycerol. This process is optimized employing a response surface analysis and using a 3² factorial design. The factors evaluated were: amount of water and tartaric acid, where tartaric acid acts as crosslinking agent and catalyst; mechanical properties of foams were evaluated as bulk density (ASTM D1622-08, compressive strength (ASTM D1621, thermal conductivity (ASTM C177-04, and friability (ASTM C421-8; scanning electronic microscopic (SEM and differential scanning calorimetry (DSC. The macropolyol was obtained from renewable sources by the transesterification of castor oil (CO or maleinized castor oil (MACO and polyglycerol (PG. The effect of microwaves on the reactions was

Comparison of environmentally friendly, selective polyurethane catalysts

Czech Academy of Sciences Publication Activity Database

Strachota, Adam; Strachotová, Beata; Špírková, Milena

2008-01-01

Roč. 23, č. 6 (2008), s. 566-570 ISSN 1042-6914 R&D Projects: GA MPO FT-TA3/034 Institutional research plan: CEZ:AV0Z40500505 Keywords : amine catalyst * foam * gelation * kinetics * polyurethane Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.706, year: 2008

Synthesis of α-Fe2O3 and Fe-Mn Oxide Foams with Highly Tunable Magnetic Properties by the Replication Method from Polyurethane Templates

Science.gov (United States)

Feng, Yuping; Fornell, Jordina; Zhang, Huiyan; Solsona, Pau; Barό, Maria Dolors; Suriñach, Santiago; Sort, Jordi

2018-01-01

Open cell foams consisting of Fe and Fe-Mn oxides are prepared from metallic Fe and Mn powder precursors by the replication method using porous polyurethane (PU) templates. First, reticulated PU templates are coated by slurry impregnation. The templates are then thermally removed at 260 °C and the debinded powders are sintered at 1000 °C under N2 atmosphere. The morphology, structure, and magnetic properties are studied by scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry, respectively. The obtained Fe and Fe-Mn oxide foams possess both high surface area and homogeneous open-cell structure. Hematite (α-Fe2O3) foams are obtained from the metallic iron slurry independently of the N2 flow. In contrast, the microstructure of the FeMn-based oxide foams can be tailored by adjusting the N2 flow. While the main phases for a N2 flow rate of 180 L/h are α-Fe2O3 and FeMnO3, the predominant phase for high N2 flow rates (e.g., 650 L/h) is Fe2MnO4. Accordingly, a linear magnetization versus field behavior is observed for the hematite foams, while clear hysteresis loops are obtained for the Fe2MnO4 foams. Actually, the saturation magnetization of the foams containing Mn increases from 5 emu/g to 52 emu/g when the N2 flow rate (i.e., the amount of Fe2MnO4) is increased. The obtained foams are appealing for a wide range of applications, such as electromagnetic absorbers, catalysts supports, thermal and acoustic insulation systems or wirelessly magnetically-guided porous objects in fluids. PMID:29439450

Polyurethane Foam Wound Dressing Technique for Areola Skin Graft Stabilization and Nipple Protection After Nipple-Areola Reconstruction.

Science.gov (United States)

Satake, Toshihiko; Muto, Mayu; Nagashima, Yu; Haga, Shoko; Homma, Yuki; Nakasone, Reiko; Kadokura, Marina; Kou, Seiko; Fujimoto, Hiroshi; Maegawa, Jiro

2018-04-01

We describe a new wound management technique using a soft dressing material to stabilize the areola skin graft and protect the nipple after nipple-areola reconstruction at the final stage of breast reconstruction. We introduced a center-fenestrated multilayered hydrocellular polyurethane foam dressing material that provides adequate pressure and retains a moist environment for a smooth skin graft "take." Moreover, the reconstructed nipple can be monitored at any time through the fenestrated window for adequate blood circulation. Altogether, this simple and inexpensive wound dressing technique improves the clinical outcome. Level of Evidence IV This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Application of polyurethane foam as a sorbent for trace metal pre-concentration — A review

Science.gov (United States)

Lemos, V. A.; Santos, M. S.; Santos, E. S.; Santos, M. J. S.; dos Santos, W. N. L.; Souza, A. S.; de Jesus, D. S.; das Virgens, C. F.; Carvalho, M. S.; Oleszczuk, N.; Vale, M. G. R.; Welz, B.; Ferreira, S. L. C.

2007-01-01

The first publication on the use of polyurethane foam (PUF) for sorption processes dates back to 1970, and soon after the material was applied for separation processes. The application of PUF as a sorbent for solid phase extraction of inorganic analytes for separation and pre-concentration purposes is reviewed. The physical and chemical characteristics of PUF (polyether and polyester type) are discussed and an introduction to the characterization of these sorption processes using different types of isotherms is given. Separation and pre-concentration methods using unloaded and loaded PUF in batch and on-line procedures with continuous flow and flow injection systems are presented. Methods for the direct solid sampling analysis of the PUF after pre-concentration are discussed as well as approaches for speciation analysis. Thermodynamic proprieties of some extraction processes are evaluated and the interpretation of determined parameters, such as enthalpy, entropy and Gibbs free energy in light of the physico-chemical processes is explained.

Fire-retardant foams

Science.gov (United States)

Gagliani, J.

1978-01-01

Family of polyimide resins are being developed as foams with exceptional fire-retardant properties. Foams are potentially useful for seat cushions in aircraft and ground vehicles and for applications such as home furnishings and building-construction materials. Basic formulations can be modified with reinforcing fibers or fillers to produce celular materials for variety of applications. By selecting reactants, polymer structure can be modified to give foams with properties ranging from high resiliency and flexibility to brittleness and rigidity.

Determination of airborne, volatile amines from polyurethane foams by sorption onto a high-capacity cation-exchange resin based on poly(succinic acid).

Science.gov (United States)

Seeber, G; Buchmeiser, M R; Bonn, G K; Bertsch, T

1998-06-05

A high-capacity carboxylic acid-functionalized resin prepared by ring-opening metathesis polymerization based on cross-linked endo,endo-poly(norborn-2-ene-5,6-dicarboxylic acid) was used for the sampling of volatile, airborne amines from polyurethane (PU) foams. Six tertiary amines which represent commonly used promotors for the formation of PUs from diisocyanates and polyols, namely pentamethyldiethylenetriamine, diazabicyclooctane, N-methylmorpholine, N-ethylmorphine, 1,4-dimethylpiperazine and N,N-dimethylethanolamine, were sorbed onto the new resin. The sorption behavior of the new material was investigated in terms of loading capacities, the influence of concentration, flow-rate as well as of the amount of resin. Breakthrough curves were recorded from each single component as well as of mixtures thereof. Finally, the resin was used for the sampling of amines evaporating from PU foams applied in buildings. Further information about time dependent concentration profiles were obtained using a combination of GC-MS and Fourier transform IR spectroscopy.

Copper removal from aqueous solution using Aspergillus niger mycelia in free and polyurethane-bound form

Energy Technology Data Exchange (ETDEWEB)

Tsekova, K.; Ilieva, S. [Inst. of Microbiology, Bulgarian Academy of Sciences, Sofia (Bulgaria)

2001-07-01

This study assesses the ability of mycelia of Aspergillus niger B-77 (both free and immobilized on polyurethane foam) to remove copper from single-ion solution. All experiments were conducted using 0.5 mM solutions of CuSO{sub 4}.5H{sub 2} O. Mycelia immobilized on polyurethane foam cells showed a three-fold increase in uptake, compared with that of free cells. The efficiency of copper removal (mg Cu{sup 2+} removed/mg Cu{sup 2+} added) in a column system reached more than 99% before the break-through point was attained. (orig.)

Synthesis of α-Fe2O3 and Fe-Mn Oxide Foams with Highly Tunable Magnetic Properties by the Replication Method from Polyurethane Templates

Directory of Open Access Journals (Sweden)

Yuping Feng

2018-02-01

Full Text Available Open cell foams consisting of Fe and Fe-Mn oxides are prepared from metallic Fe and Mn powder precursors by the replication method using porous polyurethane (PU templates. First, reticulated PU templates are coated by slurry impregnation. The templates are then thermally removed at 260 °C and the debinded powders are sintered at 1000 °C under N2 atmosphere. The morphology, structure, and magnetic properties are studied by scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry, respectively. The obtained Fe and Fe-Mn oxide foams possess both high surface area and homogeneous open-cell structure. Hematite (α-Fe2O3 foams are obtained from the metallic iron slurry independently of the N2 flow. In contrast, the microstructure of the FeMn-based oxide foams can be tailored by adjusting the N2 flow. While the main phases for a N2 flow rate of 180 L/h are α-Fe2O3 and FeMnO3, the predominant phase for high N2 flow rates (e.g., 650 L/h is Fe2MnO4. Accordingly, a linear magnetization versus field behavior is observed for the hematite foams, while clear hysteresis loops are obtained for the Fe2MnO4 foams. Actually, the saturation magnetization of the foams containing Mn increases from 5 emu/g to 52 emu/g when the N2 flow rate (i.e., the amount of Fe2MnO4 is increased. The obtained foams are appealing for a wide range of applications, such as electromagnetic absorbers, catalysts supports, thermal and acoustic insulation systems or wirelessly magnetically-guided porous objects in fluids.

Construction of organic–inorganic hybrid nano-coatings containing α-zirconium phosphate with high efficiency for reducing fire hazards of flexible polyurethane foam

International Nuclear Information System (INIS)

Pan, Ying; Pan, Haifeng; Yuan, Bihe; Hong, Ningning; Zhan, Jing; Wang, Bibo; Song, Lei; Hu, Yuan

2015-01-01

Nano-architecture on the flexible polyurethane foam (FPUF) was built by layer by layer (LbL) self-assembling of α-zirconium phosphate (α-ZrP) and two biopolymers. Through electrostatic attraction and hydrogen bonding between α-ZrP, chitosan and alginate, the nano-coatings were successfully deposited on the substrate. The LbL self-assembly coatings were characterized by X-ray diffraction, UV–vis absorption spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy and scanning electron microscopy. This loaded nano-coating endowed FPUF with excellent flame retardancy. Compared with pure FPUF, the reduction in the peak heat release rate of the modified foam with 12.3 wt% weight gain was achieved 71%, and the melt-dripping during combustion disappeared. Meanwhile, the thermal degradation of coated FPUF under nitrogen atmosphere was obviously retarded compared with pure FPUF. Additionally, the mechanical properties of the treated FPUFs were investigated. After loaded with 12.3 wt% nano-coating, the tensile and tear strength were enhanced by 13% and 54%, respectively. These investigations indicated that the study has great potential to add new dimensions in the fire retardancy modification of FPUF. - Highlights: • The nano-coatings containing α-ZrP and two biopolymers were successfully loaded on the FPUF by LbL self-assembly method. • The hybrid nano-coatings exhibited marked reduction in the peak heat release rate of the foam. • The coating resulted in enhanced tensile and tear strength of the foam

Construction of organic–inorganic hybrid nano-coatings containing α-zirconium phosphate with high efficiency for reducing fire hazards of flexible polyurethane foam

Energy Technology Data Exchange (ETDEWEB)

Pan, Ying [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Pan, Haifeng; Yuan, Bihe [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou, Jiangsu 215123 (China); Hong, Ningning; Zhan, Jing; Wang, Bibo [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Song, Lei, E-mail: leisong@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou, Jiangsu 215123 (China)

2015-08-01

Nano-architecture on the flexible polyurethane foam (FPUF) was built by layer by layer (LbL) self-assembling of α-zirconium phosphate (α-ZrP) and two biopolymers. Through electrostatic attraction and hydrogen bonding between α-ZrP, chitosan and alginate, the nano-coatings were successfully deposited on the substrate. The LbL self-assembly coatings were characterized by X-ray diffraction, UV–vis absorption spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy and scanning electron microscopy. This loaded nano-coating endowed FPUF with excellent flame retardancy. Compared with pure FPUF, the reduction in the peak heat release rate of the modified foam with 12.3 wt% weight gain was achieved 71%, and the melt-dripping during combustion disappeared. Meanwhile, the thermal degradation of coated FPUF under nitrogen atmosphere was obviously retarded compared with pure FPUF. Additionally, the mechanical properties of the treated FPUFs were investigated. After loaded with 12.3 wt% nano-coating, the tensile and tear strength were enhanced by 13% and 54%, respectively. These investigations indicated that the study has great potential to add new dimensions in the fire retardancy modification of FPUF. - Highlights: • The nano-coatings containing α-ZrP and two biopolymers were successfully loaded on the FPUF by LbL self-assembly method. • The hybrid nano-coatings exhibited marked reduction in the peak heat release rate of the foam. • The coating resulted in enhanced tensile and tear strength of the foam.

Preparation And Characterization Of Silicon Carbide Foam By Using In-Situ Generated Polyurethane Foam

Directory of Open Access Journals (Sweden)

Shalini Saxena

2015-08-01

Full Text Available Abstract The open cell silicon carbide SiC foam was prepared using highly crosslinked hybrid organic- inorganic polymer resin matrix. As inorganic polymer polycarbosilane was taken and organic resin was taken as a mixture of epoxy resin and diisocyanates. The resultant highly crosslinked hybrid resin matrix on heating and subsequently on pyrolysis yielded open cell silicon carbide foam. The hybrid resin matrix was characterized by Fourier transform Infrared Spectroscopy FT-IR and thermal properties i.e. Thermogravimetric analysis TGA amp Differential Scanning Calorimetry DSC were also studied. The morphological studies of silicon carbide ceramic foam were carried out using X-ray Spectroscopy XRD amp Scanning Electron Microscopy SEM.

Synthesis of Foam-Shaped Nanoporous Zeolite Material: A Simple Template-Based Method

Science.gov (United States)

Saini, Vipin K.; Pires, Joao

2012-01-01

Nanoporous zeolite foam is an interesting crystalline material with an open-cell microcellular structure, similar to polyurethane foam (PUF). The aluminosilicate structure of this material has a large surface area, extended porosity, and mechanical strength. Owing to these properties, this material is suitable for industrial applications such as…

Dynamics of poroelastic foams

Science.gov (United States)

Forterre, Yoel; Sobac, Benjamin

2010-11-01

Soft poroelastic structures are widespread in biological tissues such as cartilaginous joints in bones, blood-filled placentae or plant organs. Here we investigate the dynamics of open elastic foams immersed in viscous fluids, as model soft poroelastic materials. The experiment consists in slowly compacting blocs of polyurethane solid foam embedded in silicon oil-tanks and studying their relaxation to equilibrium when the confining stress is suddenly released. Measurements of the local fluid pressure and foam velocity field are compared with a simple two-phase flow approach. For small initial compactions, the results show quantitative agreement with the classical diffusion theory of soil consolidation (Terzaghi, Biot). On the other hand, for large initial compactions, the dynamics exhibits long relaxation times and decompaction fronts, which are mainly controlled by the highly non-linear mechanical response of the foam. The analogy between this process and the evaporation of a polymer melt close to the glass transition will be briefly discussed.

75 FR 57169 - Significant New Use Rules on Certain Chemical Substances

Science.gov (United States)

2010-09-20

... be claimed as CBI. Unit IX. discusses a procedure companies may use to ascertain whether a proposed... will be as a curing agent for polyurethane systems. Based on EcoSAR analysis of test data on analogous... will be as a polyol for flexible and rigid polyurethane foam applications. Based on EcoSAR analysis of...

Preconcentration system for cadmium and lead determination in environmental samples using polyurethane foam/Me-BTANC

International Nuclear Information System (INIS)

Moreira Gama, Ednilton; Silva Lima, Adriana da; Azevedo Lemos, Valfredo

2006-01-01

In this work, polyurethane foam (PUF) loaded with 2-(6'-methyl-2'-benzothiazolylazo)chromotropic acid (Me-BTANC) was packed in a minicolumn and it was used in an on-line preconcentration system for cadmium and lead determination. Optimum hydrodynamic and chemical conditions for metal sorption were investigated. The effects of several foreign substances on the adsorption of cadmium and lead were also reported. The enrichment factor obtained was 37 (Cd and Pb) for 180 s preconcentration time. The proposed procedures allowed the determination of metals with detection limits (3σ) of 0.80 and 3.75 μg L -1 (0.10 and 0.47 μg g -1 of solid sample) for cadmium and lead, respectively. The precision of the procedures was also calculated: 3.1 (Cd 10 μg L -1 ) and 4.4% (Pb 100 μg L -1 ). The accuracy of the procedure was checked by analysis of the certified reference materials Spinach Leaves and Fish Tissue. Cadmium and lead contents in environmental samples (black tea, spinach leaves, natural and tap water) were determined by applying the proposed procedure

Foam, composition and method of production

Energy Technology Data Exchange (ETDEWEB)

Ghali, R.

1991-09-03

A ternary foam is disclosed which overcomes the disadvantages of conventional heat-insulating foams which are either dense and heavy, expensive to produce, friable, unstable, or have poor fire resistance. The foam of the invention has, by weight of the reaction product, 10-35% polyurethane, 30-55% polyisocyanurate, and 20-45% polyurea. The foam is a reaction product of 100 parts by weight of an organic polyisocyanate with: 15-25 parts by weight of a polyether polyol having a hydroxyl number of ca 28-35 and a molecular weight of not more than 6,000; 5-25 parts by weight of water; 0-25 parts by weight of a blowing agent; 0-50 parts by weight of a filler-plasticizer fire retardant; an effective amount of a low activation catalyst to initiate water-isocyanate reaction to produce polyurea and polyol-isocyanate reaction to produce polyurethane; and an effective amount of a high activation catalyst to retard the low activation catalyst and promote the formation of polyisocyanurate. The low activity catalyst is present in an amount ranging ca 1.5-9 parts per 100 parts by weight of the polyisocyanate, and the high activation catalyst is present in an amount ranging 0.0008-0.002 parts per 100 parts by weight of the polyisocyanate. Water as a reactant and blowing agent can be substituted by an effective amount of a disubstituted amine such as diethanol amine and an inert blowing agent such as fluorocarbon. The resultant foam has excellent heat insulating propeties, is semi-flexible, has a density of 0.5-0.9 lb/ft{sup 3}, and can be inexpensively produced by existing 2-component foam dispensing equipment. 1 fig., 1 tab.

An Experimental Study of the Effect of Thermal Radiation Feedback on the Room Burning Behaviour of Horizontal Blocks of Polyurethane Foam

DEFF Research Database (Denmark)

Poulsen, Annemarie; Bwalya, A.C.

-fire-retarded polyurethane foam measuring 1200 x 600 x 200 mm and weighing approximately 4.8 kg. The room tests were conducted in a small compartment measuring 2400 mm wide x 2800 mm deep x 2400 mm high with a rectangular vent (opening under a calorimeter hood) measuring 740 mm wide x 1500 mm high (a ventilation limit...... of approximately 2000 kW) located in one of the 2400 mm walls. The room was lined with one of two different non-combustible materials – 12.7 mm thick cement board or 50 mm thick mineral wool insulation – with substantially differential thermal inertias in order to subject the test specimen to one of two thermal...

Occupational exposure to polybrominated diphenyl ethers (PBDEs) and other flame retardant foam additives at gymnastics studios: Before, during and after the replacement of pit foam with PBDE-free foams.

Science.gov (United States)

Ceballos, Diana M; Broadwater, Kendra; Page, Elena; Croteau, Gerry; La Guardia, Mark J

2018-07-01

Coaches spend long hours training gymnasts of all ages aided by polyurethane foam used in loose blocks, mats, and other padded equipment. Polyurethane foam can contain flame retardant additives such as polybrominated diphenyl ethers (PBDEs), to delay the spread of fires. However, flame retardants have been associated with endocrine disruption and carcinogenicity. The National Institute for Occupational Safety and Health (NIOSH) evaluated employee exposure to flame retardants in four gymnastics studios utilized by recreational and competitive gymnasts. We evaluated flame retardant exposure at the gymnastics studios before, during, and after the replacement of foam blocks used in safety pits with foam blocks certified not to contain several flame retardants, including PBDEs. We collected hand wipes on coaches to measure levels of flame retardants on skin before and after their work shift. We measured flame retardant levels in the dust on window glass in the gymnastics areas and office areas, and in the old and new foam blocks used throughout the gymnastics studios. We found statistically higher levels of 9 out of 13 flame retardants on employees' hands after work than before, and this difference was reduced after the foam replacement. Windows in the gymnastics areas had higher levels of 3 of the 13 flame retardants than windows outside the gymnastics areas, suggesting that dust and vapor containing flame retardants became airborne. Mats and other padded equipment contained levels of bromine consistent with the amount of brominated flame retardants in foam samples analyzed in the laboratory. New blocks did not contain PBDEs, but did contain the flame retardants 2-ethylhexyl 2,3,4,5-tetrabromobenzoate and 2-ethylhexyl 2,3,4,5-tetrabromophthalate. We conclude that replacing the pit foam blocks eliminated a source of PBDEs, but not 2-ethylhexyl 2,3,4,5-tetrabromobenzoate and 2-ethylhexyl 2,3,4,5-tetrabromophthalate. We recommend ways to further minimize employee exposure

Polyurethane foam loaded with sodium dodecylsulfate for the extraction of 'quat' pesticides from aqueous medium: Optimization of loading conditions.

Science.gov (United States)

Vinhal, Jonas O; Lima, Claudio F; Cassella, Ricardo J

2016-09-01

The cationic herbicides paraquat, diquat and difenzoquat are largely used in different cultures worldwide. With this, there is an intrinsic risk of environmental contamination when these herbicides achieve natural waters. The goal of this work was to propose a novel and low-cost sorbent for the removal of the cited herbicides from aqueous medium. The proposed sorbent was prepared by loading polyurethane foam with sodium dodecylsulfate. The influence of several parameters (SDS concentration, HCl concentration and shaking time) on the loading process was investigated. The results obtained in this work demonstrated that all studied variables influenced the loading process, having significant effect on the extraction efficiency of the resulted PUF-SDS. At optimized conditions, the PUF was loaded by shaking 200mg of crushed foam with 200mL of a solution containing 5.0×10(-3)molL(-1) SDS and 0.25molL(-1) HCl, for 30min. The obtained PUF-SDS was efficient for removing the three herbicides from aqueous medium, achieving extraction percentages higher than 90%. The sorption process followed a pseudo second-order kinetics, which presented excellent predictive capacity of the amount of herbicide retained with time. Copyright © 2016 Elsevier Inc. All rights reserved.

Experimental Characterization of the Energy Absorption of Functionally Graded Foam Filled Tubes Under Axial Crushing Loads

Science.gov (United States)

Ebrahimi, Saeed; Vahdatazad, Nader; Liaghat, Gholamhossein

2018-03-01

This paper deals with the energy absorption characterization of functionally graded foam (FGF) filled tubes under axial crushing loads by experimental method. The FGF tubes are filled axially by gradient layers of polyurethane foams with different densities. The mechanical properties of the polyurethane foams are firstly obtained from axial compressive tests. Then, the quasi-static compressive tests are carried out for empty tubes, uniform foam filled tubes and FGF filled tubes. Before to present the experimental test results, a nonlinear FEM simulation of the FGF filled tube is carried out in ABAQUS software to gain more insight into the crush deformation patterns, as well as the energy absorption capability of the FGF filled tube. A good agreement between the experimental and simulation results is observed. Finally, the results of experimental test show that an FGF filled tube has excellent energy absorption capacity compared to the ordinary uniform foam-filled tube with the same weight.

Vegetable-origin foam employed in dye extraction in tanning and leather processing facilities

Directory of Open Access Journals (Sweden)

José M. Cangemi

2009-01-01

Full Text Available This study addressed the use of conventional and vegetable origin polyurethane foams to extract C. I. Acid Orange 61 dye. The quantitative determination of the residual dye was carried out with an UV/Vis absorption spectrophotometer. The extraction of the dye was found to depend on various factors such as pH of the solution, foam cell structure, contact time and dye and foam interactions. After 45 days, better results were obtained for conventional foam when compared to vegetable foam. Despite presenting a lower percentage of extraction, vegetable foam is advantageous as it is considered a polymer with biodegradable characteristics.

Rigid Polyurethane Nanocomposites Prepared by Direct Incorporation: Effects of Nanoclay, Carbon Nanotubes and Mixing Speed on Physical and Morphological Properties

Science.gov (United States)

Ramadhoni, Benni; Ujianto, Onny; Nadapdap, Maxwell

2018-03-01

Rigid polyurethane (PU) nanocomposites were fabricated via solution mixing of PU, nanoclay and multiwalled carbon nanotubes (MWCNT) according to full factorial DoE. The nanoclay and MWCNT concentration as well as mixing speed were varied. The effects of controlled variables on reduced compressive strength, fire retardancy, hardness and morphological properties were analized. In general, the results showed that incorporation of nanofillers into PU matrix successfully elevated nanocomposites performance. The properties changed from -12% to 45% for reduced compressive strength, 9% to 30% for reduced fire retardancy and -32% to 101% for reduced hardness. The results suggested that the improvements were affected by nanoclay dispersion that acted as nucleating agent which resulted in smaller close cells of PU structures.

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.

Pourable Foam Insulation

Science.gov (United States)

Harvey, James A.; Butler, John M.; Chartoff, Richard P.

1989-01-01

Report describes search for polyisocyanurate/polyurethane foam insulation with superior characteristics. Discusses chemistry of current formulations. Tests of formulations, of individual ingredients and or alternative new formulations described. Search revealed commercially available formulations exhibiting increased thermal stability at temperatures up to 600 degree C, pours readily before curing, presents good appearance after curing, and remains securely bonded to aluminum at cryogenic temperatures. Total of 42 different formulations investigated, 10 found to meet requirements.

One-dimensional thermal response modeling of a transuranic foamed overpack system to a fire

International Nuclear Information System (INIS)

Suchsland, K.E.; Kwong, K.C.; Fretter, E.F.; Boyd, R.D.; Auerbach, I.; Yoshimura, H.R.

1980-01-01

Procedures have been established for modeling the thermal response of TRU container walls (TRUPACT) exposed to a fire environment. The effort included simulation testing and thermal modeling of the wall material. In this study, both testing and modeling were directed at determining a one-dimensional thermal model for undamaged polyurethane foam. The foam was assumed to exist in a nonoxidizing environment and was exposed to an almost step change in surface temperature. Results indicate that if the TRU waste container wall includes a polyurethane foam (64 kg/m 3 density) of thickness greater than 20 cm and the wall is otherwise undamaged, there will be no change in the waste content temperature where the container is subjected to a surface temperature as high as 1333 K for times less than 3600 s. Further improvements are needed in the thermal model to include transpiration, better estimates of the temperature-dependent thermal conductivity, effects of damaged wall structure and radiation absorption effects for the charged foam. 10 figures

Infrared Thermography As Quality Control For Foamed In-Place Insulation

Science.gov (United States)

Schwartz, Joel A.

1989-03-01

Since November of 1985, FOAM-TECH, INC. has been utilizing an I.S.I. Model 91 Videotherm Camera to quality control the installation of foamed in-place polyurethane and polyisocyanurate insulation. Monitoring the injection of foam into the walls and roofs of new construction and during the the retrofitting of older buildings has become an integral and routine step in daily operations. The Videotherm is also used to monitor the injection of foam into hot water tanks, trailer bodies for refrigeration trucks, and pontoons and buoys for flotation. The camera is also used for the detection of heat loss and air infiltration for conventionally insulated buildings. Appendix A are thermograms of foamed in-place insulation.

Synthesis of waterborne, branched, functional poly(urethane)s and theire applications

OpenAIRE

Ongun, Nihan

2014-01-01

Polyurethanes are an important class of polymers that have wide application in a number of different industrial sectors. Their versatile chemistry enables researchers to design novel materials ranging from liquid, soft and rubbery solids to rigid thermoplastic and thermoset polymer for elastomeric materials, coating and adhesive. The present study focuses on synthesizing waterborne, branched and chemically functional polyurethanes with unique architectures via novel methodologies for coating ...

Occupational exposure to diisocyanates in polyurethane foam factory workers

Directory of Open Access Journals (Sweden)

Dominika Świerczyńska-Machura

2015-12-01

Full Text Available Objectives: The aim of the study was to evaluate health effects of occupational exposure to diisocyanates (DIC among polyurethane foam products factory workers. Material and Methods: Thirty workers had a physical examination, skin prick tests with common allergens, allergen-specific immunoglobulin E (IgE antibodies to diisocyanates and pulmonary function tests. Concentrations of selected isocyanates in the workplace air samples as well as concentration of their metabolites in the urine samples collected from the workers of the plant were determined. Results: The most frequent work-related symptoms reported by the examined subjects were rhinitis and skin symptoms. Sensitization to at least 1 common allergen was noted in 26.7% of the subjects. Spirometry changes of bronchial obstruction of a mild degree was observed in 5 workers. The specific IgE antibodies to toluene diisocyanate (TDI and 4,4’-methylenebis(phenyl isocyanate (MDI were not detected in any of the patients’ serum. Cellular profiles of the collected induced sputum (ISP did not reveal any abnormalities. Air concentrations of TDI isomers ranged 0.2–58.9 μg/m3 and in 7 cases they exceeded the Combined Exposure Index (CEI value for those compounds. Concentrations of TDI metabolites in post-shift urine samples were significantly higher than in the case of pre-shift urine samples and in 6 cases they exceeded the British Biological Monitoring Guidance Value (BMGV – 1 μmol amine/mol creatinine. We didn’t find a correlation between urinary concentrations of TDI, concentrations in the air and concentrations of toluenediamine (TDA in the post shift urine samples. Lack of such a correlation may be an effect of the respiratory protective equipment use. Conclusions: Determination of specific IgE in serum is not sensitive enough to serve as a biomarker. Estimation of concentrations of diisocyanate metabolites in urine samples and the presence of work-related allergic symptoms seem to be

Exposure to organophosphate flame retardants in spray polyurethane foam applicators: Role of dermal exposure.

Science.gov (United States)

Bello, Anila; Carignan, Courtney C; Xue, Yalong; Stapleton, Heather M; Bello, Dhimiter

2018-04-01

Spray polyurethane foam (SPF) is a highly effective thermal insulation material that has seen considerable market growth in the past decade. Organophosphate flame retardants (PFRs) are added to SPF formulations to meet fire code requirements. A common flame retardant used in SPF formulations is tris 1-chloro 2-propyl phosphate (TCIPP), a suspected endocrine disruptor. Exposure monitoring efforts during SPF applications have focused primarily on the isocyanate component, a potent respiratory and dermal sensitizer. However, to our knowledge, there is no monitoring data for TCIPP. To characterize occupational exposures to TCIPP and other flame retardants during SPF insulation. Workers at four SPF insulation sites and one foam removal site (total n = 14) were recruited as part of this pilot study. Personal inhalation exposure to TCIPP was monitored with a CIP-10MI inhalable sampler and potential dermal exposure was assessed through the use of a glove dosimeter. Biomarkers of TCIPP and three other PFRs were measured in urine collected from workers pre-and post-shift. Linear mixed effect models were used to analyze associations of urinary biomarkers with inhalation and dermal exposures and paired t-tests were used to examine the difference on the means of urinary biomarkers pre-and post-shift. Chemical analysis of all species was performed with liquid chromatography-electrospray ionization tandem mass spectrometry. Geometric mean (GM) concentrations of TCIPP in personal air monitors and glove dosimeters collected from SPF applicators, 294.7 μg/m 3 and 18.8 mg/pair respectively. Overall, GM concentrations of the two TCIPP urinary biomarkers BCIPP and BCIPHIPP and (6.2 and 88.8 μg/mL) were 26-35 times higher than reported in the general population. Post-shift levels of TCIPP biomarkers were higher than pre-shift even though workers at insulation sites wore supplied air respirators, gloves and coveralls. The urinary biomarkers for the other PFRs were not

Field calibration of polyurethane foam (PUF) disk passive air samplers for PCBs and OC pesticides.

Science.gov (United States)

Chaemfa, Chakra; Barber, Jonathan L; Gocht, Tilman; Harner, Tom; Holoubek, Ivan; Klanova, Jana; Jones, Kevin C

2008-12-01

Different passive air sampler (PAS) strategies have been developed for sampling in remote areas and for cost-effective simultaneous spatial mapping of POPs (persistent organic pollutants) over differing geographical scales. The polyurethane foam (PUF) disk-based PAS is probably the most widely used. In a PUF-based PAS, the PUF disk is generally mounted inside two stainless steel bowls to buffer the air flow to the disk and to shield it from precipitation and light. The field study described in this manuscript was conducted to: compare performance of 3 different designs of sampler; to further calibrate the sampler against the conventional active sampler; to derive more information on field-based uptake rates and equilibrium times of the samplers. Samplers were also deployed at different locations across the field site, and at different heights up a meteorological tower, to investigate the possible influence of sampler location. Samplers deployed <5m above ground, and not directly sheltered from the wind gave similar uptake rates. Small differences in dimensions between the 3 designs of passive sampler chamber had no discernable effect on accumulation rates, allowing comparison with previously published data.

The role of nanocrystalline cellulose on the microstructure of foamed castor-oil polyurethane nanocomposites.

Science.gov (United States)

Cordero, Andrés Ignacio; Amalvy, Javier Ignacio; Fortunati, Elena; Kenny, José María; Chiacchiarelli, Leonel Matías

2015-12-10

Nanocrystalline cellulose (CNC), obtained by sulphuric acid hydrolysis, was used to synthesize polyurethane foams (PUFs) based on a functionalized castor oil polyol and a Methylene diphenyl diisocyanate (MDI). Formulations with varying isocyanate index (FI) and NCO number were prepared. At 0.5 wt.%, SEM's of the fractured surface underlined that the CNC acted both as a nucleation agent and as a particulate surfactant with cell geometries and apparent density changing selectively. The chemical structure of the PUF (FTIR) changed after the incorporation of CNC by a relative change of the amount of urea, urethane and isocyanurate groups. A low NCO number and isocyanate index contributed to the migration of the CNC to the Hard Segment (HS), acting as reinforcement and improving substantially the compressive mechanical properties (Ec and σc improvements of 63 and 50%, respectively). For a high NCO number or isocyanate index, the CNC migrated to the Soft Segment (SS), without causing a reinforcement effect. The migration of the CNC was also detected with DSC, TGA and DMA, furtherly supporting the hypothesis that a low NCO number and index contributed both to the formation of a microstructure with a higher content of urethane groups. Copyright © 2015 Elsevier Ltd. All rights reserved.

Photometric determination of vanadium(V) after adsorption of its Schiff's base (derived from 2-aminopyridine and naphthalene-1-carbaldehyde) complex on polyurethane foam

International Nuclear Information System (INIS)

Chandak, Priti; Singhal, Sumeet; Mathur, Nidhi; Mathur, S.P.

1997-01-01

The absorbance of vanadium(V) complex of Schiff's base derived from 2-aminopyridine and naphthalene-1-carbaldehyde after preliminary adsorption of polyurethane foam has been studied. It is found that Beer's law is obeyed over the concentration range 10-85 μg of vanadium(V) in 10 ml chloroform. Molar absorptivity and sensitivity are calculated to be 6.6 x 10 4 1 mol -1 cm -1 and 0.061 μg cm -2 of V(V) respectively at 495 nm. The effects of pH, reagent concentration, absorbent, diverse metal ions on photometric determination of vanadium have been studied. The method has been applied satisfactorily for determination of vanadium in OHNS steel alloy sample. (author)

Mechanical properties of tannin-based rigid foams undergoing compression

Energy Technology Data Exchange (ETDEWEB)

Celzard, A., E-mail: Alain.Celzard@enstib.uhp-nancy.fr [Institut Jean Lamour - UMR CNRS 7198, CNRS - Nancy-Universite - UPV-Metz, Departement Chimie et Physique des Solides et des Surfaces, ENSTIB, 27 rue du Merle Blanc, BP 1041, 88051 Epinal cedex 9 (France); Zhao, W. [Institut Jean Lamour - UMR CNRS 7198, CNRS - Nancy-Universite - UPV-Metz, Departement Chimie et Physique des Solides et des Surfaces, ENSTIB, 27 rue du Merle Blanc, BP 1041, 88051 Epinal cedex 9 (France); Pizzi, A. [ENSTIB-LERMAB, Nancy-University, 27 rue du Merle Blanc, BP 1041, 88051 Epinal cedex 9 (France); Fierro, V. [Institut Jean Lamour - UMR CNRS 7198, CNRS - Nancy-Universite - UPV-Metz, Departement Chimie et Physique des Solides et des Surfaces, ENSTIB, 27 rue du Merle Blanc, BP 1041, 88051 Epinal cedex 9 (France)

2010-06-25

The mechanical properties of a new class of extremely lightweight tannin-based materials, namely organic foams and their carbonaceous counterparts are detailed. Scaling laws are shown to describe correctly the observed behaviour. Information about the mechanical characteristics of the elementary forces acting within these solids is derived. It is suggested that organic materials present a rather bending-dominated behaviour and are partly plastic. On the contrary, carbon foams obtained by pyrolysis of the former present a fracture-dominated behaviour and are purely brittle. These conclusions are supported by the differences in the exponent describing the change of Young's modulus as a function of relative density, while that describing compressive strength is unchanged. Features of the densification strain also support such conclusions. Carbon foams of very low density may absorb high energy when compressed, making them valuable materials for crash protection.

Novel Foams Based on Freeze-Dried Renewable Vital Wheat Gluten

DEFF Research Database (Denmark)

Blomfeldt, Thomas O.J.; Olsson, Richard T.; Menon, Mohan

2010-01-01

A new way of producing rigid or semi-rigid foams from vital wheat gluten using a freeze-drying process is reported. Water/gluten-based mixtures were frozen and freeze-dried. Different foam structures were obtained by varying the mixing process and wheat gluten concentration, or by adding glycerol...... or bacterial cellulose nanofibers. MIP revealed that the foams had mainly an open porosity peaking at 93%. The average pore diameter ranged between 20 and 73 µm; the sample with the highest wheat gluten concentration and no plasticizer had the smallest pores. Immersion tests with limonene revealed...

The Development of Testing Methods for Characterizing Emissions and Sources of Exposures from Polyurethane Products

Science.gov (United States)

The relationship between onsite manufacture of spray polyurethane foam insulation (SPFI) and potential exposures is not well understood. Currently, no comprehensive standard test methods exist for characterizing and quantifying product emissions. Exposures to diisocyanate compoun...

EXPERIMENTAL STUDIES ON THE QUASI-STATIC AXIAL CRUSHING BEHAVIOR OF FOAM-FILLED STEEL EXTRUSION TUBES

OpenAIRE

AL EMRAN ISMAIL

2010-01-01

The concerns of automotive safety have been given special attention in order to reduce human fatalities or injuries. One of the techniques to reduce collision impact or compression energy is by filling polymeric foam into metallic tubes. In this work, polyurethane foam was introduced into the steel extrusion tubes and quasi-statically compressed at constant cross-head displacement. Different tube thicknesses and foam densities were used and these parameters were related to the crashwor...

Making continuous bubble type polyethylene foam incombustible

International Nuclear Information System (INIS)

Kaji, Kanako; Hatada, Motoyoshi; Yoshizawa, Iwao; Komai, Kuniaki; Kohara, Choji.

1989-01-01

Since continuous bubble type plastic foam has excellent compression characteristics and sound absorption characteristics, it has been widely used as cushion material, sealing material, sound insulating material and so on. However, the most part of plastic foam is taken by air, therefore at the time of fires, it becomes a very dangerous material. At present, the material used mostly as the seat cushions for airliners, railroad coaches, automobiles and others is polyurethane foam, but since it contains C-N couples in its molecules, it is feared to generate cyanic gas according to the condition of combustion. As the plastic foam that does not generate harmful gas at the time of fires, there is continuous bubble type polyethylene which is excellent in its weathering property and chemical resistance. A reactive, phosphorus-containing oligomer has large molecular weight and two or more double couplings in a molecule, therefore, it does not enter the inside of polyethylene, and polymerizes and crosslinks on the surfaces of bubble walls in the foam, accordingly it is expected that the apparent graft polymerization is carried out, and it is very effective for making polyethylene foam incombustible. The method of making graft foam, the properties of graft foam and so on are reported. When the graft polymerization of this oligomer to continuous bubble type polyethylene foam was tried, highly incombustible polyethylene foam was obtained. (K.I.)

Foam insulated transfer line test report

International Nuclear Information System (INIS)

Squier, D.M.

1994-06-01

Miles of underground insulated piping will be installed at the Hanford site to transfer liquid waste. Significant cost savings may be realized by using pre-fabricated polyurethane foam insulated piping. Measurements were made on sections of insulated pipe to determine the insulation's resistance to axial expansion of the pipe, the force required to compress the foam in the leg of an expansion loop and the time required for heat up and cool down of a buried piping loop. These measurements demonstrated that the peak axial force increases with the amount of adhesion between the encasement pipe and the insulation. The compressive strength of the foam is too great to accommodate the thermal growth of long straight pipe sections into the expansion loops. Mathematical models of the piping system's thermal behavior can be refined by data from the heated piping loop

Auxetic foam for snowsport safety devices

OpenAIRE

Allen, Tom; Duncan, Olly; Foster, Leon; Senior, Terry; Zampieri, Davide; Edeh, Victor; Alderson, Andrew

2017-01-01

Skiing and snowboarding are popular snow-sports with inherent risk of injury. There is potential to reduce the prevalence of injuries by improving and implementing snow-sport safety devices with the application of advanced materials. This paper investigates the application of auxetic foam to snow-sport safety devices. Composite pads - consisting of foam covered with a semi-rigid shell - were investigated as a simple model of body armour and a large 70 x 355 x 355 mm auxetic foam sample was fa...

The important parameters of polyurethane's properties and preparation

International Nuclear Information System (INIS)

Rad, A.S.

2009-01-01

Polyurethane (PU) is a type of plastic rind is formed by reacting a polyol (a polymeric alcohol with more than. two reactive hydroxyl groups per molecule) with diisocyanates or polymeric isocyanate in the presence of suitable catalysts and additives. Variations in the number of substitutions and the spacing between and within branch chains produce PUs ranging from linear to branched and flexible to rigid. Linear PUs are used for the manufacture of fibers and molding. The structure of polyurethane can be medley containing 'hard' and 'soft' sect, which contribute to the harmony between rigid and elastomeric properties. The chemical composition and molecular weight distribution (MWD)- of the incorporated soft block influence the macroscopic properties of the resulting coating. In modifying the backbone structure of PU coatings it is necessary to consider the end use for the coating and the cost of modification: The properties of the modified PU coating, The resistance of the coating towards mechanical and The compatibility of the coating and the substrate over the temperature range of expected application and The between the benefits to be gained and the additional cost are the parameters that must be A surface functionalization of a synthetic polyurethane was carried out by using biofunctional moieties to obtain a material with the appropriate mechanical properties and processing conditions. (author)

Adsorption of the herbicides diquat and difenzoquat on polyurethane foam: Kinetic, equilibrium and computational studies.

Science.gov (United States)

Vinhal, Jonas O; Nege, Kassem K; Lage, Mateus R; de M Carneiro, José Walkimar; Lima, Claudio F; Cassella, Ricardo J

2017-11-01

This work reports a study about the adsorption of the herbicides diquat and difenzoquat from aqueous medium employing polyurethane foam (PUF) as the adsorbent and sodium dodecylsulfate (SDS) as the counter ion. The adsorption efficiency was shown to be dependent on the concentration of SDS in solution, since the formation of an ion-associate between cationic herbicides (diquat and difenzoquat) and anionic dodecylsulfate is a fundamental step of the process. A computational study was carried out to identify the possible structure of the ion-associates that are formed in solution. They are probably formed by three units of dodecylsulfate bound to one unit of diquat, and two units of dodecylsulfate bound to one unit of difenzoquat. The results obtained also showed that 95% of both herbicides present in 45mL of a solution containing 5.5mgL -1 could be retained by 300mg of PUF. The experimental data were well adjusted to the Freundlich isotherm (r 2 ≥ 0.95) and to the pseudo-second-order kinetic equation. Also, the application of Morris-Weber and Reichenberg equations indicated that an intraparticle diffusion process is active in the control of adsorption kinetics. Copyright © 2017 Elsevier Inc. All rights reserved.

Magnetically-tunable rebound property for variable elastic devices made of magnetic elastomer and polyurethane foam

Science.gov (United States)

Oguro, Tsubasa; Endo, Hiroyuki; Kawai, Mika; Mitsumata, Tetsu

2017-12-01

A device consisting of a phase of magnetic elastomer, a phase of polyurethane foam (PUF), and permanent magnet was fabricated and the stress-strain curves for the two-phase magnetic elastomer were measured by a uniaxial compression measurement. A disk of magnetic elastomer was adhered on a disk of PUF by an adhesive agent. The PUF thickness was varied from 1 mm to 5 mm while the thickness of magnetic elastomers was constant at 5 mm. The stress at a strain of 0.15 for the two-phase magnetic elastomers was evaluated in the absence and in the presence of a magnetic field of 410 mT. The stress at 0 mT decreased remarkably with the PUF thickness due to the deformation of the PUF phase. On the other hand, the stress at 410 mT slightly decreased with the thickness; however, it kept high values even at high thickness. When the PUF thickness was 5 mm, the maximum stress increment with 45 times to the off-field stress was observed. An experiment using ping-pong balls demonstrated that the coefficient of restitution for the two-phase magnetic elastomers can be dramatically altered by the magnetic field.

TOPEM DSC study of glass transition region of polyurethane cationomers

International Nuclear Information System (INIS)

Pielichowska, Kinga; Król, Piotr; Król, Bożena; Pagacz, Joanna

2012-01-01

Highlights: ► TOPEM DSC method was employed to investigate the glass transition (T g ) region of fluorinated polyurethane cationomers. ► Introduction of fluorine compounds significantly changes thermal behaviour of cationomers in the T g region of hard segments. ► Introduction of fluorine compound leads to changes of the slope in activation diagram of glass transition. - Abstract: In this paper TOPEM DSC method was employed to investigate the glass transition region of fluorinated polyurethane cationomers. Fluorinated polyurethane cationomers have been synthesised in the reaction of MDI with poly(ethylene glycol) (600) and butane1,4-diol or N-methyl- or N-butyldiethanolamine and 2,2,3,3-tetrafluoro-1,4-butanediol. Better rigidity was found for generally amorphous cationomer coats. It was found that introduction of fluorine compound changes thermal behaviour of polyurethane cationomers as well as leads to changes in the slope in activation diagram profiles of glass transition in comparison to polyuretahene cationomer without fluorine compound. Application of TOPEM DSC allows to obtain more information concerning frequency dependence of glass transition region and thermodynamical stability of polyurethane structures.

Performance evaluation of poly-urethane foam packed-bed chemical scrubber for the oxidative absorption of NH3 and H2S gases.

Science.gov (United States)

Nisola, Grace M; Valdehuesa, Kris Niño G; Anonas, Alex V; Ramos, Kristine Rose M; Lee, Won-Keun; Chung, Wook-Jin

2018-01-02

The feasibility of open-pore polyurethane (PU) foam as packing material for wet chemical scrubber was tested for NH 3 and H 2 S removals. The foam is inexpensive, light-weight, highly porous (low pressure drop) and provides large surface area per unit volume, which are desirable properties for enhanced gas/liquid mass transfer. Conventional HCl/HOCl (for NH 3 ) and NaOH/NaOCl (for H 2 S) scrubbing solutions were used to absorb and oxidize the gases. Assessment of the wet chemical scrubbers reveals that pH and ORP levels are important to maintain the gas removal efficiencies >95%. A higher re-circulation rate of scrubbing solutions also proved to enhance the performance of the NH 3 and H 2 S columns. Accumulation of salts was confirmed by the gradual increase in total dissolved solids and conductivity values of scrubbing solutions. The critical elimination capacities at >95% gas removals were found to be 5.24 g NH 3 -N/m 3 -h and 17.2 g H 2 S-S/m 3 -h at an empty bed gas residence time of 23.6 s. Negligible pressure drops (scrubbers for NH 3 and H 2 S removals from high-volume dilute emissions.

Design and milling manufacture of polyurethane custom contoured cushions for wheelchair users

Directory of Open Access Journals (Sweden)

Wilson Kindlein Junior

2011-09-01

Full Text Available BackgroundThe design of custom contoured cushions manufactured inflexible polyurethane foams is an option to improvepositioning and comfort for people with disabilities thatspend most of the day seated in the same position. Thesesurfaces increase the contact area between the seat and theuser. This fact contributes to minimise the local pressuresthat can generate problems like decubitus ulcers. Thepresent research aims at establishing development routesfor custom cushion production to wheelchair users. Thisstudy also contributes to the investigation of ComputerNumerical Control (CNC machining of flexible polyurethanefoams.MethodThe proposed route to obtain the customised seat beganwith acquiring the user’s contour in adequate posturethrough plaster cast. To collect the surface geometry, thecast was three-dimensionally scanned and manipulated inCAD/CAM software. CNC milling parameters such as tools,spindle speeds and feed rates to machine flexiblepolyurethane foams were tested. These parameters wereanalysed regarding the surface quality. The best parameterswere then tested in a customised seat. The possibledimensional changes generated during foam cutting wereanalysed through 3D scanning. Also, the customised seatpressure and temperature distribution was tested.ResultsThe best parameters found for foams with a density of50kg/cm3 were high spindle speeds (24000 rpm and feedrates between 2400–4000mm/min. Those parameters didnot generate significant deformities in the machinedcushions. The custom contoured cushion satisfactorilyincreased the contact area between wheelchair and user, asit distributed pressure and heat evenly.ConclusionThrough this study it was possible to define routes for thedevelopment and manufacturing of customised seats usingdirect CNC milling in flexible polyurethane foams. It alsoshowed that custom contoured cushions efficientlydistribute pressure and temperature, which is believed tominimise tissue lesions such as pressure

Sorption of oil in the polyurethane from oil or castor oil; Sorcao de oleo no poliuretano derivado do petroleo ou do oleo de mamona

Energy Technology Data Exchange (ETDEWEB)

Florentino, Wagner M; Goulart, Shane A.S.; Mulinari, Daniella R. [Centro Universitario de Volta Redonda (UniFOA), Volta Redonda, RJ (Brazil)], e-mail: wagner-can@hotmail.com

2011-07-01

The oil outpouring has caused serious environmental problems. To minimize this damage polyurethane foams have been used. In this work, the use of polyurethane from oil and castor oil, in different polyol/diisocyanate mass ratios, to absorb oil was evaluated. Results revealed that the proportion of polyol and diisocyanate influenced in the sorption capacity and the polyurethane from castor oil presented greater sorption capacity. Of this way, can say that the polyurethane from oil can be replaced by castor oil, contributing to sustainable development. (author)

Biodegradation of polyurethane derived from castor oil

Directory of Open Access Journals (Sweden)

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.

Repeated batch cultivation of the hydrocarbon-degrading, micro-algal strain Prototheca zopfii RND16 immobilized in polyurethane foam.

Science.gov (United States)

Ueno, Ryohei; Wada, Shun; Urano, Naoto

2008-01-01

This study reports on the stability of the cells of a heterotrophic green micro-algal strain Prototheca zopfii RND16 immobilized in polyurethane foam (PUF) cubes during degradation of mixed hydrocarbon substrate, which was composed of n-alkanes and polycyclic aromatic hydrocarbons (PAHs), in 5 successive cycles of repeated batch cultivation at 30 degrees C. Both RND16 cells and mixed hydrocarbon substrate components had been entrapped in PUF cubes through cultivation. PUF-immobilized RND16 degraded n-alkanes almost completely, whereas the strain hardly degraded PAHs in PUFs, rather they accumulated in the matrices. It is noteworthy that this result is strikingly different from that of the free-living cell culture, where RND16 reduced concentrations of both n-alkanes and PAHs. However, PAHs accumulation in the PUFs did not impair the performance of the immobilized alga to utilize n-alkanes. These results suggest that the PUFs harboring RND16 cells could be used repeatedly for selective retrieval of PAHs from oil-polluted waters after preferential biodegradation of n-alkanes by algae.

Ceramic Foams from Pre-Ceramic Polymer Routes for Reusable Acreage Thermal Protection System Applications

Science.gov (United States)

Stackpoole, Mairead; Chien, Jennifer; Schaeffler, Michelle

2004-01-01

Contents include the following: Motivation. Current light weight insulation. Advantages of preceramic-polymer-derived ceramic foams. Rigid insulation materials. Tailor foam microstructures. Experimental approach. Results: sacrificial materials, sacrificial fillers. Comparison of foam microstructures. Density of ceramic foams. Phase evolution and properties: oxidation behavior. mechanical properties, aerothermal performance. Impact damage of microcellular foams. Conclusions.

Geometry anisotropy and mechanical property isotropy in titanium foam fabricated by replica impregnation method

International Nuclear Information System (INIS)

Manonukul, Anchalee; Srikudvien, Pathompoom; Tange, Makiko; Puncreobutr, Chedtha

2016-01-01

Polyurethane (PU) foams have both geometry and mechanical property anisotropy. Metal foams, which are manufacturing by investment casting or melt deposition method and using PU foam as a template, also have mechanical property anisotropy. This work studied the mechanical properties in two directions of titanium foam with four different cell sizes fabricated using the replica impregnation method. The two directions are (1) the loading direction parallel to the foaming direction where the cells are elongated (EL direction) and (2) the loading direction perpendicular to the foaming direction where the cell are equiaxed (EQ direction). The results show that the compression responses for both EL and EQ directions are isotropy. Micrographs and X-ray micro-computed tomography show that the degree of geometry anisotropy is not strong enough to results in mechanical property anisotropy.

Geometry anisotropy and mechanical property isotropy in titanium foam fabricated by replica impregnation method

Energy Technology Data Exchange (ETDEWEB)

Manonukul, Anchalee, E-mail: anchalm@mtec.or.th [National Metal and Materials Technology Center (MTEC), National Science and Technology Development Agency (NSTDA), 114 Thailand Science Park, Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Srikudvien, Pathompoom [National Metal and Materials Technology Center (MTEC), National Science and Technology Development Agency (NSTDA), 114 Thailand Science Park, Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Tange, Makiko [Taisei Kogyo Thailand Co., Ltd., Room INC2d-409, Innovation Cluster 2 Building, Tower D, 141 Thailand Science Park, Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Puncreobutr, Chedtha [Department of Metallurgical Engineering, Faculty of Engineering, Chulalongkorn University, Pathumwan, Bangkok 10330 (Thailand)

2016-02-08

Polyurethane (PU) foams have both geometry and mechanical property anisotropy. Metal foams, which are manufacturing by investment casting or melt deposition method and using PU foam as a template, also have mechanical property anisotropy. This work studied the mechanical properties in two directions of titanium foam with four different cell sizes fabricated using the replica impregnation method. The two directions are (1) the loading direction parallel to the foaming direction where the cells are elongated (EL direction) and (2) the loading direction perpendicular to the foaming direction where the cell are equiaxed (EQ direction). The results show that the compression responses for both EL and EQ directions are isotropy. Micrographs and X-ray micro-computed tomography show that the degree of geometry anisotropy is not strong enough to results in mechanical property anisotropy.

Polyurethane scaffold formation via a combination of salt leaching and thermally induced phase separation

NARCIS (Netherlands)

Heijkants, R. G. J. C.; van Calck, R. V.; van Tienen, T. G.; de Groot, J. H.; Pennings, A. J.; Buma, P.; Veth, R. P. H.; Schouten, A. J.

2008-01-01

Porous scaffolds have been made from two polyurethanes based on thermally induced phase separation of polymer dissolved in a DMSO/water mixture in combination with salt leaching. It is possible to obtain very porous foams with a very high interconnectivity. A major advantage of this method is that

Microcellular foams via phase separation

International Nuclear Information System (INIS)

Young, A.T.

1985-01-01

A study of wide variety of processes for making plastic foams shows that phase separation processes for polymers from solutions offers the most viable methods for obtaining rigid plastic foams which met the physical requirements for fusion target designs. Four general phase separation methods have been shown to give polymer foams with densities less than 0.1 g/cm 3 and cell sizes of 30μm or less. These methods involve the utilization of non-solvent, chemical or thermal cooling processes to achieve a controlled phase separation wherein either two distinct phases are obtained where the polymer phase is a continuous phase or two bicontinuous phases are obtained where both the polymer and solvent are interpenetrating, continuous, labyrinthine phases. Subsequent removal of the solvent gives the final foam structure

Structures and Properties of Polyurethanes. Part II,

Science.gov (United States)

1979-03-23

effect was observed for polymethyl methacrylate (222, 2721. The polyol, which contain fluorine , decrease adhesion, in spite DOC = 79011112 PAGE S4% of...small differences in the hardness of films on the basis of the fluorine -bearing polyol and generally accepted polyol. Is investigated the etfect ot...polyurethane, to rigid surface. DOC 79011112 P A * S The effect of the solvent, utilized for obtaining the varnish , on adhesion is investigated in

Test and development of microcapsules for rigid polyurethane foam

OpenAIRE

Loureiro, Mónica de Jesus Veiga

2016-01-01

Tese de mestrado em Química Tecnológica, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2016 O mercado dos poliuretanos encontra-se, de momento, em expansão. No ano de 2012, a Asia foi o maior produtor de poliuretano, tendo sido responsável pela produção de cerca de 10 milhões de toneladas, seguida pela Europa com uma produção anual de 4 milhões de toneladas. No ano de 2013 a produção mundial de latas de espuma de poliuretano atingiu as 600 mil toneladas, sendo esp...

Exploiting novel sterilization techniques for porous polyurethane scaffolds.

Science.gov (United States)

Bertoldi, Serena; Farè, Silvia; Haugen, Håvard Jostein; Tanzi, Maria Cristina

2015-05-01

Porous polyurethane (PU) structures raise increasing interest as scaffolds in tissue engineering applications. Understanding the effects of sterilization on their properties is mandatory to assess their potential use in the clinical practice. The aim of this work is the evaluation of the effects of two innovative sterilization techniques (i.e. plasma, Sterrad(®) system, and ozone) on the morphological, chemico-physical and mechanical properties of a PU foam synthesized by gas foaming, using water as expanding agent. In addition, possible toxic effects of the sterilization were evaluated by in vitro cytotoxicity tests. Plasma sterilization did not affect the morphological and mechanical properties of the PU foam, but caused at some extent degradative phenomena, as detected by infrared spectroscopy. Ozone sterilization had a major effect on foam morphology, causing the formation of new small pores, and stronger degradation and oxidation on the structure of the material. These modifications affected the mechanical properties of the sterilized PU foam too. Even though, no cytotoxic effects were observed after both plasma and ozone sterilization, as confirmed by the good values of cell viability assessed by Alamar Blue assay. The results here obtained can help in understanding the effects of sterilization procedures on porous polymeric scaffolds, and how the scaffold morphology, in particular porosity, can influence the effects of sterilization, and viceversa.

Preparation and characterization of shape memory composite foams with interpenetrating polymer networks

International Nuclear Information System (INIS)

Yao, Yongtao; Zhou, Tianyang; Yang, Cheng; Leng, Jinsong; Liu, Yanju

2016-01-01

The present study reports a feasible approach of fabricating shape memory composite foams with an interpenetrating polymer network (IPN) based on polyurethane (PU) and shape memory epoxy resin (SMER) via a simultaneous polymerization technique. The PU component is capable of constructing a foam structure and the SMER is grafted on the PU network to offer its shape memory property in the final IPN foams. A series of IPN foams without phase separation were produced due to good compatibility and a tight chemical interaction between PU and SMER components. The relationships of the geometry of the foam cell were investigated via varying compositions of PU and SMER. The physical property and shape memory property were also evaluated. The stimulus temperature of IPN shape memory composite foams, glass temperature (T g ), could be tunable by varying the constituents and T g of PU and SMER. The mechanism of the shape memory effect of IPN foams has been proposed. The shape memory composite foam with IPN developed in this study has the potential to extend its application field. (paper)

Recycling of PUR scrap from car seats-glycolysis of flexible PUR foam

Czech Academy of Sciences Publication Activity Database

Beneš, Hynek; Holler, Petr; Schmidt, Pavel; Horák, Zdeněk; Rösner, J.

2005-01-01

Roč. 99, - (2005), s. 29 ISSN 0009-2770. [International Conference on Polymeric Materials in Automotive , Slovak Rubber Conference /17./. 10.5.2005-12.5.2005, Bratislava] Institutional research plan: CEZ:AV0Z40500505 Keywords : chemical recycling * flexible polyurethane foam * glycolysis Subject RIV: CD - Macromolecular Chemistry

Tooling Foam for Structural Composite Applications

Science.gov (United States)

DeLay, Tom; Smith, Brett H.; Ely, Kevin; MacArthur, Doug

1998-01-01

Tooling technology applications for composite structures fabrication have been expanded at MSFC's Productivity Enhancement Complex (PEC). Engineers from NASA/MSFC and Lockheed Martin Corporation have developed a tooling foam for use in composite materials processing and manufacturing that exhibits superior thermal and mechanical properties in comparison with other tooling foam materials. This tooling foam is also compatible with most preimpregnated composite resins such as epoxy, bismaleimide, phenolic and their associated cure cycles. MARCORE tooling foam has excellent processability for applications requiring either integral or removable tooling. It can also be tailored to meet the requirements for composite processing of parts with unlimited cross sectional area. A shelf life of at least six months is easily maintained when components are stored between 50F - 70F. The MARCORE tooling foam system is a two component urethane-modified polyisocyanurate, high density rigid foam with zero ozone depletion potential. This readily machineable, lightweight tooling foam is ideal for composite structures fabrication and is dimensionally stable at temperatures up to 350F and pressures of 100 psi.

(H)-FCKW foamed insulating materials in the building industry in Germany. Estimation of the potential emissions up to the year 2010; (H)-FCKW-geschaeumte Daemmstoffe im Bauwesen in Deutschland. Schaetzung der potentiellen Emissionen bis zum Jahr 2010

Energy Technology Data Exchange (ETDEWEB)

Obernosterer, Richard [Ressourcen Management Agentur GmbH, Villach (Austria)

2012-09-15

CFCs and HCFCs are controlled substances under European Regulation (EC) No. 1005/2009. Article 22 of that Regulation provides that controlled substances contained in certain products (e.g. insulating materials) must be recovered, if technically and economically feasible, or be destroyed without prior recovery. Annex VII lists specific technologies for destruction, recycling or reclamation. In Germany, the use of (H)CFCs in insulating materials has been prohibited since 1995 (R 11 and R 12) and 2000 (R 22). At European level, use of HCFCs (141b and 142b) has been banned since 2002 mainly in the production of extruded polystyrene rigid foam and since 2003 in the production of polyurethane foams. Few data have become available to date on the amounts of (H)CFCs produced and banked up to the time the prohibitions went into effect. The present report therefore provides details on the amounts of (H)CFC-containing insulating materials installed in Germany and estimates the quantities of (H)CFCs still present in them. The study focuses on rigid XPS foam and rigid PU foam used in the construction sector, due to the original objective of the study and the quantitative significance of these foams. XPS insulating foams: XPS panels were assumed to have an average density of 33 kg/m3. Based on annual foam use (volume), density, the market shares of the blowing agents, and blowing agent content in the foam, the annual increase in banked amounts of blowing agents was estimated. Annual fugitive losses were deducted from those banks, specific to the relevant products and blowing agents. As result a bank of approximately 43.7 kt or 15 000 t-ODP was estimated for Germany in 2009. PU insulating foams: Based on annual foam use (volume), density (assumed to be 41 kg/m3 for PU sandwich panels and 33 kg/m3 for other PU products), the market shares of the blowing agents, and blowing agent content in the foam, the annual increase in banked amounts of blowing agents was estimated. Annual

The In Vivo Pericapsular Tissue Response to Modern Polyurethane Breast Implants.

Science.gov (United States)

Frame, James; Kamel, Dia; Olivan, Marcelo; Cintra, Henrique

2015-10-01

Polyurethane breast implants were first introduced by Ashley (Plast Reconstr Surg 45:421-424, 1970), with the intention of trying to reduce the high incidence of capsular contracture associated with smooth shelled, high gel bleed, silicone breast implants. The sterilization of the polyurethane foam in the early days was questionable. More recently, ethylene oxide (ETO)-sterilized polyurethane has been used in the manufacturing process and this has been shown to reduce the incidence of biofilm. The improved method of attachment of polyurethane onto the underlying high cohesive gel, barrier shell layered, silicone breast implants also encourages bio-integration. Polyurethane covered, cohesive gel, silicone implants have also been shown to reduce the incidence of other problems commonly associated with smooth or textured silicone implants, especially with reference to displacement, capsular contracture, seroma, reoperation, biofilm and implant rupture. Since the introduction of the conical polyurethane implant (Silimed, Brazil) into the United Kingdom in 2009 (Eurosurgical, UK), we have had the opportunity to review histology taken from the capsules of polyurethane implants in three women ranging from a few months to over 3 years after implantation. All implants had been inserted into virgin subfascial, extra-pectoral planes. The results add to the important previously described histological findings of Bassetto et al. (Aesthet Plast Surg 34:481-485, 2010). Five distinct layers are identified and reasons for the development of each layer are discussed. Breast capsule around polyurethane implants, in situ for fifteen and 20 years, has recently been obtained and analysed in Brazil, and the histology has been incorporated into this study. After 20 years, the polyurethane is almost undetectable and capsular contracture may appear. These findings contribute to our understanding of polyurethane implant safety, and give reasoning for a significant reduction in clinical

Quasi-static characterisation and impact testing of auxetic foam for sports safety applications

International Nuclear Information System (INIS)

Duncan, Olly; Alderson, Andrew; Foster, Leon; Senior, Terry; Allen, Tom

2016-01-01

This study compared low strain rate material properties and impact force attenuation of auxetic foam and the conventional open-cell polyurethane counterpart. This furthers our knowledge with regards to how best to apply these highly conformable and breathable auxetic foams to protective sports equipment. Cubes of auxetic foam measuring 150 × 150 × 150 mm were fabricated using a thermo–mechanical conversion process. Quasi-static compression confirmed the converted foam to be auxetic, prior to being sliced into 20 mm thick cuboid samples for further testing. Density, Poisson’s ratio and the stress–strain curve were all found to be dependent on the position of each cuboid from within the cube. Impact tests with a hemispherical drop hammer were performed for energies up to 6 J, on foams covered with a polypropylene sheet between 1 and 2 mm thick. Auxetic samples reduced peak force by ∼10 times in comparison to the conventional foam. This work has shown further potential for auxetic foam to be applied to protective equipment, while identifying that improved fabrication methods are required. (paper)

Investigation on the effect of formulation and process variables of Polyethylene Foams Production

International Nuclear Information System (INIS)

Barikani, H.; Sarai, M.

2001-01-01

Polyolefin foams such as polyethylene, polypropylene and their copolymers have been extensively used in packaging, automotive, military, marine, cable industries and sports, due to their unique properties namely: light weight, chemical resistance, thermal insulation, inertness, abrasion resistance, buoyancy and low cost. With regards to domestic mass production of polyethylene, replacement of polyurethane with polyethylene foam is very important in some applications from economical point of view. In this research preparation of high density and low density polyethylene foams were studied and the effect of formulation factors such as blowing agent, cross-linker, calcium carbonate, zinc oxide and processing factors such as heat, pressure and reaction time on density and cell size were investigated

Elaboration of recycled polyethylene foams reticulated by radiation

International Nuclear Information System (INIS)

Galicia M, M.

2000-01-01

In this work some obtained results are presented to make irradiation tests on recycled polymeric material (polyethylene) as well as mixtures of this with certain additive classes (foaming and reticulating agents) which will be used for the foams elaboration, objective of this work. Two types of foaming basically exist which are elaborated with low density polyethylene base. They are: a) the extruded and, b) the reticulated through ionizing radiation and chemically. Some of the properties that the expanded or foamed polyethylene are: flexibility, resistance, thermal stability, inter medium mechanical properties between the highly flexible foams and rigid among others. All of them determined by the cell type which conform them. Also was carried out the characterization of the obtained material contributing of this manner to diminish the quantity of solid wastes generated. (Author)

Synthesis and Properties of Novel Polyurethane Containing Nitrophenylazocatecholic Group as NLO Chromophore

International Nuclear Information System (INIS)

Song, Mi Young; Kim, Mi Sung; Lee, Ju Yeon

2012-01-01

The promise of NLO polymers lies in their higher nonlinear optical activity, faster response time, and easy fabrication into electro-optic devices. In the developments of NLO polymers for electrooptic device applications, stabilization of electrically induced dipole alignment is one of important considerations; in this context, two approaches to minimize the randomization have been proposed, namely the use of cross-linked systems and the utilization of polymers with high glass transition temperature (T g ) such as polyimides. A polyurethane matrix forms extensive hydrogen bonding between urethane linkages, with increased rigidity preventing the relaxation of induced dipoles. Polyurethanes functionalized with hemicyanine and thiophene ring in side chain show an enhanced thermal stability of aligned dipoles. Polyurethanes with NLO chromophores, whose dipole moments are aligned transverse to the main chains, show large second-order nonlinearity with good thermal stability

Application Waste Sawdust as Mixed Polyurethane Insulation in Traditional Cold Storage of Fishing Vessel

Directory of Open Access Journals (Sweden)

Sutopo Purwono Fitri

2017-03-01

Full Text Available In the process of fishing it takes some supplies such as fishing equipment, instrumentation and storage of fish. The traditional fishermen of their fishing days fishing usually only bring ice cubes. Solid plastic polyurethane foam is a mixture solution of polyols and isocyanates, commonly used as an insulating material storage. From the observation waste generated being sawmill sawdust per spindle with diameter of 30 cm and a length of 1 m with 5 times sawmill, Saws 0.8 cm thick produced 0.0088 m³ / burnable logs only discarded. Therefore takes thermal conductivity test to review mixture of sawdust and polyurethane comparison with variations different dosing. Maximum disposals sawdust can be done is 40% of the total volume of material mixture, polyurethane and sawdust because composite material (sawdust-polyurethane can not be bond with good so easy slab separately from origin form. Thermal Conductivity insulating good and economical on disposals 40% wood flour (0.05252 W / m°C and is able to maintain a 2 kg of ice crystals melt up perfect on 34 hours. Operating profits economical from 4,8 m³insulation composite application with obtained Rp 4.486.000 compared with 100% Polyurethane Insulation Manufacture.

Fire-Retardant, Self-Extinguishing Inorganic/Polymer Composite Memory Foams.

Science.gov (United States)

Chatterjee, Soumyajyoti; Shanmuganathan, Kadhiravan; Kumaraswamy, Guruswamy

2017-12-27

Polymeric foams used in furniture and automotive and aircraft seating applications rely on the incorporation of environmentally hazardous fire-retardant additives to meet fire safety norms. This has occasioned significant interest in novel approaches to the elimination of fire-retardant additives. Foams based on polymer nanocomposites or based on fire-retardant coatings show compromised mechanical performance and require additional processing steps. Here, we demonstrate a one-step preparation of a fire-retardant ice-templated inorganic/polymer hybrid that does not incorporate fire-retardant additives. The hybrid foams exhibit excellent mechanical properties. They are elastic to large compressional strain, despite the high inorganic content. They also exhibit tunable mechanical recovery, including viscoelastic "memory". These hybrid foams are prepared using ice-templating that relies on a green solvent, water, as a porogen. Because these foams are predominantly comprised of inorganic components, they exhibit exceptional fire retardance in torch burn tests and are self-extinguishing. After being subjected to a flame, the foam retains its porous structure and does not drip or collapse. In micro-combustion calorimetry, the hybrid foams show a peak heat release rate that is only 25% that of a commercial fire-retardant polyurethanes. Finally, we demonstrate that we can use ice-templating to prepare hybrid foams with different inorganic colloids, including cheap commercial materials. We also demonstrate that ice-templating is amenable to scale up, without loss of mechanical performance or fire-retardant properties.

Catalytic and thermodynamic properties of a tannase produced by Aspergillus niger GH1 grown on polyurethane foam.

Science.gov (United States)

Ramos, Erika L; Mata-Gómez, Marco A; Rodríguez-Durán, Luis V; Belmares, Ruth E; Rodríguez-Herrera, Raúl; Aguilar, Cristóbal Noe

2011-11-01

Tannase is an inducible enzyme with important applications in the food and pharmaceutical industries. This enzyme was produced by the fungus Aspergillus niger GH1 under solid-state fermentation using polyurethane foam as solid support and tannic acid as sole carbon source and tannase inducer. Physicochemical properties of A. niger tannase were characterized, and the kinetic and thermodynamics parameters on methyl gallate hydrolysis were evaluated. The enzyme was stable in a pH range of 2-8 and a functional temperature range of 25-65 °C. The highest k(cat) value was 2,611.10 s(-1) at 65 °C. Tannase had more affinity for methyl gallate at 45 °C with a K(M) value of 1.82 mM and an efficiency of hydrolysis (k(cat)/K(M)) of 330.01 s(-1) mM(-1). The lowest E(a) value was found to be 21.38 kJ/mol at 4.4 mM of methyl gallate. The lowest free energy of Gibbs (ΔG) and enthalpy (ΔH) were found to be 64.86 and 18.56 kJ/mol, respectively. Entropy (ΔS) was -0.22 kJ/mol K. Results suggest that the A. niger GH1 tannase is an attractive enzyme for industrial applications due its catalytic and thermodynamical properties.

Methodology for characterization of corrosive agents of thermal insulating foams; Desenvolvimento de metodologia para caracterizacao de agentes corrosivos de espumas de isolamento termico

Energy Technology Data Exchange (ETDEWEB)

Sousa, Flavio V. Vasques de [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Fundacao Coordenacao de Projetos, Pesquisas e Estudos Tecnologicos - COPPETEC; Mattos, Oscar R.; Mota, Rafael O. da [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Metalurgica e de Materiais; Margarit-Mattos, Isabel C.P. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica. Dept. de Processos Organicos; Quintela, Joaquim P. [PETROBRAS, Rio de Janeiro, RJ (Brazil); Vieira, Magda M. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

2005-07-01

Warming up oil and derivatives is a required procedure to make their transportation more efficient due to the increase in fluidity. Therefore, the use of thermally insulated pipeline becomes essential. The commonly practice has been the use of pipelines covered with an optional anticorrosive coating, followed by a polyurethane foam layer, as thermal insulator, and a polyethylene top coating for mechanical protection. During the life time of the pipeline, local ruptures of the polyethylene coating frequently occur, allowing the water permeation throughout the thermal insulator. This water may cause foam leaching that would release corrosive agents on the external wall pipe. The objective of the present work was to investigate the effects of the blowing agents, the addition of flame retardant to the foam as well as operating temperatures on the generation of corrosive solutions on the external wall of thermally insulated pipes. In this sense, polyurethane foams expanded with HCFC-141b, CFC-11 and CO{sub 2}, with and without flame retardant, were evaluated at the temperatures of 80 and 120 deg C. (author)

Road Maintenance Experience Using Polyurethane (PU) Foam Injection System and Geocrete Soil Stabilization as Ground Rehabilitation

Science.gov (United States)

Fakhar, A. M. M.; Asmaniza, A.

2016-07-01

There are many types of ground rehabilation and improvement that can be consider and implement in engineering construction works for soil improvement in order to prevent road profile deformation in later stage. However, when comes to road maintenance especially on operated expressways, not all method can be apply directly as it must comply to opreation's working window and lane closure basis. Key factors that considering ideal proposal for ground rehabilitation are time, cost, quality and most importantly practicality. It should provide long lifespan structure in order to reduce continuous cycle of maintenance. Thus, this paper will present two approaches for ground rehabilitation, namely Polyurethane (PU) Foam Injection System and Geocrete Soil Stabilization. The first approach is an injection system which consists two-parts chemical grout of Isocynate and Polyol when mixed together within soil structure through injection will polymerized with volume expansion. The strong expansion of grouting causes significant compression and compacting of the surrounding soil and subsequently improve ground properties and uplift sunken structure. The later is a cold in-place recyclying whereby mixture process that combines in-situ soil materials, cement, white powder (alkaline) additive and water to produce hard yet flexible and durable ground layer that act as solid foundation with improved bearing capacity. The improvement of the mechanical behaviour of soil through these two systems is investigated by an extensive testing programme which includes in-situ and laboratory test in determining properties such as strength, stiffness, compressibility, bearing capacity, differential settlement and etc.

Initial development and testing of a novel foam-based pressure sensor for wearable sensing

Directory of Open Access Journals (Sweden)

Smyth Barry

2005-03-01

Full Text Available Abstract Background This paper provides an overview of initial research conducted in the development of pressure-sensitive foam and its application in wearable sensing. The foam sensor is composed of polypyrrole-coated polyurethane foam, which exhibits a piezo-resistive reaction when exposed to electrical current. The use of this polymer-coated foam is attractive for wearable sensing due to the sensor's retention of desirable mechanical properties similar to those exhibited by textile structures. Methods The development of the foam sensor is described, as well as the development of a prototype sensing garment with sensors in several areas on the torso to measure breathing, shoulder movement, neck movement, and scapula pressure. Sensor properties were characterized, and data from pilot tests was examined visually. Results The foam exhibits a positive linear conductance response to increased pressure. Torso tests show that it responds in a predictable and measurable manner to breathing, shoulder movement, neck movement, and scapula pressure. Conclusion The polypyrrole foam shows considerable promise as a sensor for medical, wearable, and ubiquitous computing applications. Further investigation of the foam's consistency of response, durability over time, and specificity of response is necessary.

Rigid polyurethane foam – kenaf core composites for structural applications

Science.gov (United States)

Kenaf (Hibiscus cannabinus L.) is a fast growing summer annual crop with numerous commercial applications (fibers, biofuels, bioremediation, paper pulp, building materials, cover crops, and livestock forages). The stalks of the kenaf plants contain two distinct fiber types, bast and core fibers. The...

The potential effect of differential ambient and deployment chamber temperatures on PRC derived sampling rates with polyurethane foam (PUF) passive air samplers

Energy Technology Data Exchange (ETDEWEB)

Kennedy, Karen, E-mail: k.kennedy@uq.edu.a [University of Queensland, EnTox (National Research Centre for Environmental Toxicology), 39 Kessels Rd., Coopers Plains QLD 4108 (Australia); Hawker, Darryl W. [Griffith University, School of Environment, Nathan QLD 4111 (Australia); Bartkow, Michael E. [University of Queensland, EnTox (National Research Centre for Environmental Toxicology), 39 Kessels Rd., Coopers Plains QLD 4108 (Australia); Carter, Steve [Queensland Health Forensic and Scientific Services, Coopers Plains QLD 4108 (Australia); Ishikawa, Yukari; Mueller, Jochen F. [University of Queensland, EnTox (National Research Centre for Environmental Toxicology), 39 Kessels Rd., Coopers Plains QLD 4108 (Australia)

2010-01-15

Performance reference compound (PRC) derived sampling rates were determined for polyurethane foam (PUF) passive air samplers in both sub-tropical and temperate locations across Australia. These estimates were on average a factor of 2.7 times higher in summer than winter. The known effects of wind speed and temperature on mass transfer coefficients could not account for this observation. Sampling rates are often derived using ambient temperatures, not the actual temperatures within deployment chambers. If deployment chamber temperatures are in fact higher than ambient temperatures, estimated sampler-air partition coefficients would be greater than actual partition coefficients resulting in an overestimation of PRC derived sampling rates. Sampling rates determined under measured ambient temperatures and estimated deployment chamber temperatures in summer ranged from 7.1 to 10 m{sup 3} day{sup -1} and 2.2-6.8 m{sup 3} day{sup -1} respectively. These results suggest that potential differences between ambient and deployment chamber temperatures should be considered when deriving PRC-based sampling rates. - Internal deployment chamber temperatures rather than ambient temperatures may be required to accurately estimate PRC-based sampling rates.

Bacterial biodegradation of modified polyurethane foams: comparison of single and mixed culture

International Nuclear Information System (INIS)

Obruca, S.; Morova, I.; Vojtova, L.; David, J.; Ondruska, V.; Babak, L.

2009-01-01

Polyurethanes (PUR) present widespread group of polymers which are involved in many aspects of modern life. They found use in medical, automotive and industrial fields. Live of modern industrial society is connected with accumulation of bad-degradable polymer waste including PUR materials. This situation leads to necessity to solve problems with negative effects of polymer solid waste on environment. (Author)

Evaluation of polyurethane foam passive air sampler (PUF) as a tool for occupational PAH measurements.

Science.gov (United States)

Strandberg, Bo; Julander, Anneli; Sjöström, Mattias; Lewné, Marie; Koca Akdeva, Hatice; Bigert, Carolina

2018-01-01

Routine monitoring of workplace exposure to polycyclic aromatic hydrocarbons (PAHs) is performed mainly via active sampling. However, active samplers have several drawbacks and, in some cases, may even be unusable. Polyurethane foam (PUF) as personal passive air samplers constitute good alternatives for PAH monitoring in occupational air (8 h). However, PUFs must be further tested to reliably yield detectable levels of PAHs in short exposure times (1-3 h) and under extreme occupational conditions. Therefore, we compared the personal exposure monitoring performance of a passive PUF sampler with that of an active air sampler and determined the corresponding uptake rates (Rs). These rates were then used to estimate the occupational exposure of firefighters and police forensic specialists to 32 PAHs. The work environments studied were heavily contaminated by PAHs with (for example) benzo(a)pyrene ranging from 0.2 to 56 ng m -3 , as measured via active sampling. We show that, even after short exposure times, PUF can reliably accumulate both gaseous and particle-bound PAHs. The Rs-values are almost independent of variables such as the concentration and the wind speed. Therefore, by using the Rs-values (2.0-20 m 3 day -1 ), the air concentrations can be estimated within a factor of two for gaseous PAHs and a factor of 10 for particulate PAHs. With very short sampling times (1 h), our method can serve as a (i) simple and user-friendly semi-quantitative screening tool for estimating and tracking point sources of PAH in micro-environments and (ii) complement to the traditional active pumping methods. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

The compressive behaviour and constitutive equation of polyimide foam in wide strain rate and temperature

Directory of Open Access Journals (Sweden)

Yoshimoto Akifumi

2015-01-01

Full Text Available These days, polymer foams, such as polyurethane foam and polystyrene foam, are used in various situations as a thermal insulator or shock absorber. In general, however, their strength is insufficient in high temperature environments because of their low glass transition temperature. Polyimide is a polymer which has a higher glass transition temperature and high strength. Its mechanical properties do not vary greatly, even in low temperature environments. Therefore, polyimide foam is expected to be used in the aerospace industry. Thus, the constitutive equation of polyimide foam that can be applied across a wide range of strain rates and ambient temperature is very useful. In this study, a series of compression tests at various strain rates, from 10−3 to 103 s−1 were carried out in order to examine the effect of strain rate on the compressive properties of polyimide foam. The flow stress of polyimide foam increased rapidly at dynamic strain rates. The effect of ambient temperature on the properties of polyimide foam was also investigated at temperature from − 190 °C to 270°∘C. The flow stress decreased with increasing temperature.

A review: fabrication of porous polyurethane scaffolds.

Science.gov (United States)

Janik, H; Marzec, M

2015-03-01

The aim of tissue engineering is the fabrication of three-dimensional scaffolds that can be used for the reconstruction and regeneration of damaged or deformed tissues and organs. A wide variety of techniques have been developed to create either fibrous or porous scaffolds from polymers, metals, composite materials and ceramics. However, the most promising materials are biodegradable polymers due to their comprehensive mechanical properties, ability to control the rate of degradation and similarities to natural tissue structures. Polyurethanes (PUs) are attractive candidates for scaffold fabrication, since they are biocompatible, and have excellent mechanical properties and mechanical flexibility. PU can be applied to various methods of porous scaffold fabrication, among which are solvent casting/particulate leaching, thermally induced phase separation, gas foaming, emulsion freeze-drying and melt moulding. Scaffold properties obtained by these techniques, including pore size, interconnectivity and total porosity, all depend on the thermal processing parameters, and the porogen agent and solvents used. In this review, various polyurethane systems for scaffolds are discussed, as well as methods of fabrication, including the latest developments, and their advantages and disadvantages. Copyright © 2014. Published by Elsevier B.V.

Design of single piece sabot for a single stage gas gun

Science.gov (United States)

Vemparala, Vignesh; Mathew, Arun Tom; Rao Koka, Tirumala

2017-11-01

Single piece sabot is a vital part in single stage gas guns for impact testing in aerospace industries. Depending on the type of projectile used the design of sabot varies to accommodate the testing equipment. The velocity of the projectile exiting the barrel is dependent on the material and shape of the sabot used. The material selected for the design of sabot is rigid polyurethane foam, due to their low elastic modulus and low density. Two samples of rigid PU foam is taken and tests are performed to get their exact material properties. These properties are incorporated in numerical simulation to determine the best fit for practical use. Since the PU foams has a wide range of porosity which plays a prominent role in deciding the exit velocity and accuracy of the projectile coming out of the barrel. By optimisation, to the best suitable material sample can be determined.

Technology Solutions for Existing Homes Case Study: Trade-Friendly Retrofit Insulated Panels for Existing Buildings

Energy Technology Data Exchange (ETDEWEB)

None

2016-03-01

For this project with the U.S. Department of Energy Building America team Home Innovation Research Labs, the retrofit insulated panels relied on an enhanced expanded polystyrene (EPS) for thermal resistance of R-4.5/inch, which is an improvement of 10% over conventional (white-colored) EPS. EPS, measured by its life cycle, is an alternative to commonly used extruded polystyrene and spray polyurethane foam. It is a closed-cell product made up of 90% air, and it requires about 85% fewer petroleum products for processing than other rigid foams.

Use of polyurethane foam and 3-hydroxy-7,8-benzo-1,2,3,4-tetrahydroquinoline for determination of nitrite by diffuse reflectance spectroscopy and colorimetry.

Science.gov (United States)

Apyari, V V; Dmitrienko, S G; Ostrovskaya, V M; Anaev, E K; Zolotov, Y A

2008-07-01

Polyurethane foam (PUF) has been suggested as a solid polymeric reagent for determination of nitrite. The determination is based on the diazotization of end toluidine groups of PUF with nitrite in acidic medium followed by coupling of polymeric diazonium cation with 3-hydroxy-7,8-benzo-1,2,3,4-tetrahydroquinoline. The intensely colored polymeric azodye formed in this reaction can be used as a convenient analytic form for the determination of nitrite by diffuse reflectance spectroscopy (c (min) = 0.7 ng mL(-1)). The possibility of using a desktop scanner, digital camera, and computer data processing for the numerical evaluation of the color intensity of the polymeric azodye has been investigated. A scanner and digital camera can be used for determination of nitrite with the same sensitivity and reproducibility as with diffuse reflectance spectroscopy. The approach developed was applied for determination of nitrite in river water and human exhaled breath condensate.

Experimental Evaluation of Equivalent-Fluid Models for Melamine Foam

Science.gov (United States)

Allen, Albert R.; Schiller, Noah H.

2016-01-01

Melamine foam is a soft porous material commonly used in noise control applications. Many models exist to represent porous materials at various levels of fidelity. This work focuses on rigid frame equivalent fluid models, which represent the foam as a fluid with a complex speed of sound and density. There are several empirical models available to determine these frequency dependent parameters based on an estimate of the material flow resistivity. Alternatively, these properties can be experimentally educed using an impedance tube setup. Since vibroacoustic models are generally sensitive to these properties, this paper assesses the accuracy of several empirical models relative to impedance tube measurements collected with melamine foam samples. Diffuse field sound absorption measurements collected using large test articles in a laboratory are also compared with absorption predictions determined using model-based and measured foam properties. Melamine foam slabs of various thicknesses are considered.

Bioremediation of aqueous pollutants using biomass embedded in hydrophilic foam. Final report

International Nuclear Information System (INIS)

Wilde, E.W.; Radway, J.C.; Santo Domingo, J.; Zingmark, R.G.; Whitaker, M.J.

1996-01-01

The major objective of this project was to examine the potential of a novel hydrophilic polyurethane foam as an immobilization medium for algal, bacteria, and other types of biomass, and to test the resulting foam/biomass aggregates for their use in cleaning up waters contaminated with heavy metals, radionuclides and toxic organic compounds. Initial investigations focused on the bioremoval of heavy metals from wastewaters at SRS using immobilized algal biomass. This effort met with limited success for reasons which included interference in the binding of biomass and target metals by various non-target constituents in the wastewater, lack of an appropriate wastewater at SRS for testing, and the unavailability of bioreactor systems capable of optimizing contact of target pollutants with sufficient biomass binding sites. Subsequent studies comparing algal, bacterial, fungal, and higher plant biomass demonstrated that other biomass sources were also ineffective for metal bioremoval under the test conditions. Radionuclide bioremoval using a Tc-99 source provided more promising results than the metal removal studies with the various types of biomass, and indicated that the alga Cyanidium was the best of the tested sources of biomass for this application. However, all of the biomass/foam aggregates tested were substantially inferior to a TEVA resin for removing Tc-99 in comparative testing. The authors also explored the use of hydrophilic polyurethane foam to embed Burkholderia cepacia, which is an efficient degrader of trichloroethylene (TCE), a contaminant of considerable concern at SRS and elsewhere. The embedded population proved to be incapable of growth on nutrient media, but retained respiratory activity. Lastly, the degradative capabilities of embedded G4 were examined. Phenol- or benzene-induced bacteria retained the ability to degrade TCE and benzene. The authors were successful in inducing enzyme activity after the organisms had already been embedded

Bioremediation of aqueous pollutants using biomass embedded in hydrophilic foam. Final report

Energy Technology Data Exchange (ETDEWEB)

Wilde, E.W.; Radway, J.C.; Santo Domingo, J.; Zingmark, R.G.; Whitaker, M.J.

1996-12-31

The major objective of this project was to examine the potential of a novel hydrophilic polyurethane foam as an immobilization medium for algal, bacteria, and other types of biomass, and to test the resulting foam/biomass aggregates for their use in cleaning up waters contaminated with heavy metals, radionuclides and toxic organic compounds. Initial investigations focused on the bioremoval of heavy metals from wastewaters at SRS using immobilized algal biomass. This effort met with limited success for reasons which included interference in the binding of biomass and target metals by various non-target constituents in the wastewater, lack of an appropriate wastewater at SRS for testing, and the unavailability of bioreactor systems capable of optimizing contact of target pollutants with sufficient biomass binding sites. Subsequent studies comparing algal, bacterial, fungal, and higher plant biomass demonstrated that other biomass sources were also ineffective for metal bioremoval under the test conditions. Radionuclide bioremoval using a Tc-99 source provided more promising results than the metal removal studies with the various types of biomass, and indicated that the alga Cyanidium was the best of the tested sources of biomass for this application. However, all of the biomass/foam aggregates tested were substantially inferior to a TEVA resin for removing Tc-99 in comparative testing. The authors also explored the use of hydrophilic polyurethane foam to embed Burkholderia cepacia, which is an efficient degrader of trichloroethylene (TCE), a contaminant of considerable concern at SRS and elsewhere. The embedded population proved to be incapable of growth on nutrient media, but retained respiratory activity. Lastly, the degradative capabilities of embedded G4 were examined. Phenol- or benzene-induced bacteria retained the ability to degrade TCE and benzene. The authors were successful in inducing enzyme activity after the organisms had already been embedded.

Magnetically driven floating foams for the removal of oil contaminants from water.

Science.gov (United States)

Calcagnile, Paola; Fragouli, Despina; Bayer, Ilker S; Anyfantis, George C; Martiradonna, Luigi; Cozzoli, P Davide; Cingolani, Roberto; Athanassiou, Athanassia

2012-06-26

In this study, we present a novel composite material based on commercially available polyurethane foams functionalized with colloidal superparamagnetic iron oxide nanoparticles and submicrometer polytetrafluoroethylene particles, which can efficiently separate oil from water. Untreated foam surfaces are inherently hydrophobic and oleophobic, but they can be rendered water-repellent and oil-absorbing by a solvent-free, electrostatic polytetrafluoroethylene particle deposition technique. It was found that combined functionalization of the polytetrafluoroethylene-treated foam surfaces with colloidal iron oxide nanoparticles significantly increases the speed of oil absorption. Detailed microscopic and wettability studies reveal that the combined effects of the surface morphology and of the chemistry of the functionalized foams greatly affect the oil-absorption dynamics. In particular, nanoparticle capping molecules are found to play a major role in this mechanism. In addition to the water-repellent and oil-absorbing capabilities, the functionalized foams exhibit also magnetic responsivity. Finally, due to their light weight, they float easily on water. Hence, by simply moving them around oil-polluted waters using a magnet, they can absorb the floating oil from the polluted regions, thereby purifying the water underneath. This low-cost process can easily be scaled up to clean large-area oil spills in water.

Observations on persistent organic pollutants in indoor and outdoor air using passive polyurethane foam samplers

Science.gov (United States)

Bohlin, Pernilla; Jones, Kevin C.; Tovalin, Horacio; Strandberg, Bo

Air quality data of persistent organic pollutants (POPs) indoors and outdoors are sparse or lacking in several parts of the world, often hampered by the cost and inconvenience of active sampling techniques. Cheap and easy passive air sampling techniques are therefore helpful for reconnaissance surveys. As a part of the Megacity Initiative: Local and Global Research Observations (MILAGRO) project in Mexico City Metropolitan Area in 2006, a range of POPs (polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs)) were analyzed in polyurethane foam (PUF) disks used as passive samplers in indoor and outdoor air. Results were compared to those from samplers deployed simultaneously in Gothenburg (Sweden) and Lancaster (United Kingdom). Using sampling rates suggested in the literature, the sums of 13 PAHs in the different sites were estimated to be 6.1-180 ng m -3, with phenanthrene as the predominant compound. Indoor PAH levels tended to be higher in Gothenburg and outdoor levels higher in Mexico City. The sum of PCBs ranged 59-2100 ng m -3, and seemed to be highest indoors in Gothenburg and Lancaster. PBDE levels (sum of seven) ranged 0.68-620 ng m -3, with the highest levels found in some indoor locations. OCPs (i.e. DDTs, HCHs, and chlordanes) were widely dispersed both outdoors and indoors at all three studied areas. In Gothenburg all POPs tended to be higher indoors than outdoors, while indoor and outdoor levels in Mexico City were similar. This could be due to the influence of indoor and outdoor sources, air exchange rates, and lifestyle factors. The study demonstrates how passive samplers can provide quick and cheap reconnaissance data simultaneously at many locations which can shed light on sources and other factors influencing POP levels in air, especially for the gaseous fractions.

UV-A photocatalytic treatment of Legionella pneumophila bacteria contaminated airflows through three-dimensional solid foam structured photocatalytic reactors

Energy Technology Data Exchange (ETDEWEB)

Josset, Sebastien; Hajiesmaili, Shabnam; Begin, Dominique; Edouard, David; Pham-Huu, Cuong [Laboratoire des Materiaux, Surfaces et Procedes pour la Catalyse (LMSPC), European Laboratory for Catalysis and Surface Sciences (ELCASS), CNRS, Strasbourg University, 25 rue Becquerel 67087 Strasbourg (France); Lett, Marie-Claire [Laboratoire de Genetique Moleculaire, Genomique, Microbiologie, CNRS, Strasbourg University, 28, rue Goethe 67083 Strasbourg Cedex (France); Keller, Nicolas, E-mail: nkeller@chimie.u-strasbg.fr [Laboratoire des Materiaux, Surfaces et Procedes pour la Catalyse (LMSPC), European Laboratory for Catalysis and Surface Sciences (ELCASS), CNRS, Strasbourg University, 25 rue Becquerel 67087 Strasbourg (France); Keller, Valerie [Laboratoire des Materiaux, Surfaces et Procedes pour la Catalyse (LMSPC), European Laboratory for Catalysis and Surface Sciences (ELCASS), CNRS, Strasbourg University, 25 rue Becquerel 67087 Strasbourg (France)

2010-03-15

A 3D-structured photocatalytic media was designed for allowing a tubular reactor to work in a traversing-flow mode at low pressure drops with a strong increase in the surface area-to-volume ratio inside the reactor. A protective polysiloxane coating was performed for protecting a structured polyurethane foam and anchoring the active TiO{sub 2} particles. Filled with the 3D-structured solid foam supporting TiO{sub 2} photocatalyst, the reactor could thus take advantages from the static mixer effect and from the low pressure drop resulting from the reticulated foam support. Very efficient decontamination levels towards airborne Legionella pneumophila bacteria were reached in a single-pass test mode.

High Temperature Epoxy Foam: Optimization of Process Parameters

Directory of Open Access Journals (Sweden)

Samira El Gazzani

2016-06-01

Full Text Available For many years, reduction of fuel consumption has been a major aim in terms of both costs and environmental concerns. One option is to reduce the weight of fuel consumers. For this purpose, the use of a lightweight material based on rigid foams is a relevant choice. This paper deals with a new high temperature epoxy expanded material as substitution of phenolic resin, classified as potentially mutagenic by European directive Reach. The optimization of thermoset foam depends on two major parameters, the reticulation process and the expansion of the foaming agent. Controlling these two phenomena can lead to a fully expanded and cured material. The rheological behavior of epoxy resin is studied and gel time is determined at various temperatures. The expansion of foaming agent is investigated by thermomechanical analysis. Results are correlated and compared with samples foamed in the same temperature conditions. The ideal foaming/gelation temperature is then determined. The second part of this research concerns the optimization of curing cycle of a high temperature trifunctional epoxy resin. A two-step curing cycle was defined by considering the influence of different curing schedules on the glass transition temperature of the material. The final foamed material has a glass transition temperature of 270 °C.

An indoor air quality evaluation in a residential retrofit project using spray polyurethane foam.

Science.gov (United States)

Tian, Shen; Ecoff, Scott; Sebroski, John; Miller, Jason; Rickenbacker, Harold; Bilec, Melissa

2018-05-01

Understanding of indoor air quality (IAQ) during and after spray polyurethane foam (SPF) application is essential to protect the health of both workers and building occupants. Previous efforts such as field monitoring, micro-chamber/spray booth emission studies, and fate/transport modeling have been conducted to understand the chemical exposure of SPF and guide risk mitigation strategies. However, each type of research has its limitation and can only reveal partial information on the relationship between SPF and IAQ. A comprehensive study is truly needed to integrate the experimental design and analytical testing methods in the field/chamber studies with the mathematical tools employed in the modeling studies. This study aims to bridge this gap and provide a more comprehensive understanding on the impact of SPF to IAQ. The field sampling plan of this research aims to evaluate the airborne concentrations of methylene diphenyl diisocyanate (MDI), formaldehyde, acetaldehyde, propionaldehyde, tris(1-chlor-2-propyl)phosphate (TCPP), trans-1-chloro-3,3,3-trifluoropropene (Solstice TM ), and airborne particles. Modifications to existing MDI sampling and analytical methods were made so that level of quantification was improved. In addition, key fate and transport modeling input parameters such as air changes per hour and airborne particle size distribution were measured. More importantly, TCPP accumulation onto materials was evaluated, which is important to study the fate and transport of semi-volatile organic compounds. The IAQ results showed that after spray application was completed in the entire building, airborne concentrations decreased for all chemicals monitored. However, it is our recommendation that during SPF application, no one should return to the application site without proper personal protection equipment as long as there are active spray activities in the building. The comparison between this field study and a recent chamber study proved surface sorption

Effects of oxygen and water content on microbial distribution in the polyurethane foam cubes of a biofilter for SO2 removal.

Science.gov (United States)

Zhang, Jingying; Li, Lin; Liu, Junxin; Wang, Yanjie

2018-01-01

The performance of a biofilter for off-gas treatment relies on the activity of microorganisms and adequate O 2 and H 2 O. In present study, a microelectrode was applied to analyze O 2 in polyurethane foam cubes (PUFCs) packed in a biofilter for SO 2 removal. The O 2 distribution varied with the density and water-containing rate (WCR) of PUFCs. The O 2 concentration dropped sharply from 10.2 to 0.8mg/L from the surface to the center of a PUFC with 97.20% of WCR. The PUFCs with high WCR presented aerobic-anoxic-aerobic areas. Three-dimensional simulated images demonstrated that the structure of PUFCs with high WCR consisted of an aerobic "shell" and an anoxic "core", with high-density PUFCs featuring a larger anoxic area than low-density PUFCs. Moreover, the H 2 O distribution in the PUFC was uneven and affected the O 2 concentration. Whereas aerobic bacteria were observed in the PUFC surface, facultative anaerobic microorganisms were found at the PUFC core, where the O 2 concentration was relatively low. O 2 and H 2 O distributions differed in the PUFCs, and the distribution of microorganisms varied accordingly. Copyright © 2017. Published by Elsevier B.V.

Building America Top Innovations 2013 Profile – Exterior Rigid Insulation Best Practices

Energy Technology Data Exchange (ETDEWEB)

none,

2013-09-01

In this Top Innovation profile, field and lab studies by BSC, PHI, and NorthernSTAR characterize the thermal, air, and vapor resistance properties of rigid foam insulation and describe best practices for their use on walls, roofs, and foundations.

SYNTHESIS, CHARACTERIZATION AND APPLICATION OF A POLYURETHANE-BASED SUPPORT FOR IMMOBILIZING MEMBRANE-BOUND LIPASE

Directory of Open Access Journals (Sweden)

M. S. Soares

Full Text Available Abstract This study conducted an assessment of polyurethane foams that were synthesized by one-shot process and used as a low-cost support to immobilize Mucor circinelloides URM 4182 whole-cells presenting high lipolytic activity. Polyols with different molecular weights (1100 to 6000 g mol-1 were applied to synthesize the polymer matrix, and the agitation speed effect was used for controlling the average pore size of the investigated polyurethane foams. The physical and mechanical properties of the polymers were evaluated by standard test methods, and their morphology was identified by Scanning Electron Microscopy. The immobilization procedure efficiency was assessed by quantifying the capability of the matrices to attach the cells and the catalytic activity of the biocatalysts in both aqueous (olive oil hydrolysis and non-aqueous media (ethanolysis of babassu oil under single and consecutive batch runs. Although all synthesized matrices were suitable to immobilize the whole cells with high catalytic performance, a better set of parameters was attained when the polyol ether with molecular weight of 6000 g mol-1 and 1100 g mol-1 was used. Both matrices yielded immobilized biocatalysts with high hydrolysis and transesterification activities, and exhibited a satisfactory operational stability with 96% and 81% retention of their initial hydrolytic and transesterification activities after three consecutive batch runs.

76 FR 19182 - Petition for Rulemaking-Classification of Polyurethane Foam and Certain Finished Products...

Science.gov (United States)

2011-04-06

... would disrupt this just-in-time manufacturing process are a recipe for job loss. AHFA asked that PHMSA... of this large production volume, the polyurethanes industry directly creates 47,500 jobs paying $2... liquid and the flash point of the liquids is >500 [deg]F, which is outside of the range and criteria of...

Study on Microstructures and Mechanical Properties of Foam Titanium Carbide Ceramics Fabricated by Reaction Sintering Process

Science.gov (United States)

Ma, Yana; Bao, Chonggao; Chen, Jie; Song, Suocheng; Han, Longhao

2018-05-01

Foam titanium carbide (TiC) ceramics with a three-dimensional network structure were fabricated by the reaction sintering process, in which polyurethane foam was taken as the template, and TiO2 and phenolic resin were used as the reactants. Phase, microstructures and fracture morphologies of foam TiC ceramics were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results show that when the mass ratios of phenolic resin and TiO2 (F/T) are (0.8-1.2): 1, foam TiC ceramics with pure TiC phase can be formed. As the F/T ratios increase, crystal lattice parameters of fabricated foam TiC ceramics become bigger. When the value of F/T decreases from 1.2 to 0.8, grain size of TiC grows larger and microstructures get denser; meanwhile, the compressive strength increases from 0.10 to 1.05 MPa. Additionally, either raising the sintering temperatures or extending holding time can facilitate the completion of the reaction process and increase the compressive strength.

Testing and modeling the dynamic response of foam materials for blast protection

Science.gov (United States)

Fitek, John H.

The pressure wave released from an explosion can cause injury to the lungs. A personal armor system concept for blast lung injury protection consists of a polymer foam layer behind a rigid armor plate to be worn over the chest. This research develops a method for testing and modeling the dynamic response of foam materials to be used for down-selection of materials for this application. Constitutive equations for foam materials are incorporated into a lumped parameter model of the combined armor plate and foam system. Impact testing and shock tube testing are used to measure the foam model parameters and validate the model response to a pressure wave load. The plate and foam armor model is then coupled to a model of the human thorax. With a blast pressure wave input, the armor model is evaluated based on how it affects the injury-causing mechanism of chest wall motion. Results show that to reduce chest wall motion, the foam must compress at a relatively constant stress level, which requires a sufficient foam thickness.

Self-fitting shape memory polymer foam inducing bone regeneration: A rabbit femoral defect study.

Science.gov (United States)

Xie, Ruiqi; Hu, Jinlian; Hoffmann, Oskar; Zhang, Yuanchi; Ng, Frankie; Qin, Tingwu; Guo, Xia

2018-04-01

Although tissue engineering has been attracted greatly for healing of critical-sized bone defects, great efforts for improvement are still being made in scaffold design. In particular, bone regeneration would be enhanced if a scaffold precisely matches the contour of bone defects, especially if it could be implanted into the human body conveniently and safely. In this study, polyurethane/hydroxyapatite-based shape memory polymer (SMP) foam was fabricated as a scaffold substrate to facilitate bone regeneration. The minimally invasive delivery and the self-fitting behavior of the SMP foam were systematically evaluated to demonstrate its feasibility in the treatment of bone defects in vivo. Results showed that the SMP foam could be conveniently implanted into bone defects with a compact shape. Subsequently, it self-matched the boundary of bone defects upon shape-recovery activation in vivo. Micro-computed tomography determined that bone ingrowth initiated at the periphery of the SMP foam with a constant decrease towards the inside. Successful vascularization and bone remodeling were also demonstrated by histological analysis. Thus, our results indicate that the SMP foam demonstrated great potential for bone regeneration. Copyright © 2018 Elsevier B.V. All rights reserved.

Characterization of compressive and short beam shear strength of bamboo opened cell foam core sandwich composites

Energy Technology Data Exchange (ETDEWEB)

Setyawan, Paryanto Dwi, E-mail: paryanto-ds@yahoo.com; Sugiman,; Saputra, Yudhi [Department of Mechanical Engineering, Faculty of Engineering, University of Mataram, Mataram, West Nusa Tenggara (Indonesia)

2016-03-29

The paper presents the compressive and the short beam shear strength of a sandwich composite with opened cell foam made of bamboo fiber as the core and plywood as the skins. The core thickness was varied from 10 mm to 40 mm keeping the volume fraction of fiber constant. Several test s were carried out including the core density, flatwise compressive and the short beam shear testing in three point bending. The results show that the density of bamboo opened cell foam is comparable with commercial plastic foam, such as polyurethane foam. The compressive strength tends to increase linearly with increasing the core thickness. The short beam shear failure load of the sandwich composite increases with the increase of core thickness, however on the contrary, the short beam shear strength which tends to sharply decrease from the thickness of 10 mm to 30 mm and then becomes flat.

TRU waste transportation package development

International Nuclear Information System (INIS)

Eakes, R.G.; Lamoreaux, G.H.; Romesberg, L.E.; Sutherland, S.H.; Duffey, T.A.

1980-01-01

Inventories of the transuranic wastes buried or stored at various US DOE sites are tabulated. The leading conceptual design of Type-B packaging for contact-handled transuranic waste is the Transuranic Package Transporter (TRUPACT), a large metal container comprising inner and outer tubular steel frameworks which are separated by rigid polyurethane foam and sheathed with steel plate. Testing of TRUPACT is reported. The schedule for its development is given. 6 figures

Síntesis y caracterización de espumas flexibles de poliuretano obtenidas a partir de aceite de castor maleinizado Flexible polyurethane foam synthesis and characterization obtained from maleinizated castor oil

Directory of Open Access Journals (Sweden)

Paula Mazo

2009-06-01

Full Text Available En este trabajo se realiza la síntesis de espumas flexibles de poliuretano empleando un diseño experimental Taguchi, utilizando aceite de castor con y sin maleinización, se estudia la cinética de la reacción de esterificación del aceite por cuantificación de los grupos ácido (ASTM D4662 - 03 y se evalúan las propiedades mecánicas de las espumas (densidad, resistencia tensil, % elongación, resiliencia y dureza. Norma NTC 2019 Icontec obtenidas en función de las variables de síntesis (cantidad y tipo de catalizador, relación molar aceite castor (CO - aceite maleinizado (MACO, cantidad de agua y surfactante empleado. Se realizan análisis de FTIR y SEM para las espumas. Los resultados mostraron una cinética de primer orden con respecto al anhídrido. El aceite maleinizado (MACO incrementa la resistencia mecánica de las espumas, debido al mayor entrecruzamiento por la incorporación de grupos ácido.In this work, the synthesis of polyurethane flexible foam is realized with the experimental design Taguchi, using castor oil with and without maleinization. The kinetic reaction of oil esterification was monitored by estimating the number of acid groups (ASTM D4662 - 03, and the mechanical properties of the foam were studied, including density, tensile resistance, % elongation, resilience and hardness (Norm NTC 2019 Icontec. The influence of various synthesis parameters was investigated, namely amount and type of catalyst, molar ratio of castor oil (CO - maleinizated castor oil (MACO, amount of water and surfactant used. The foams were analyzed using FTIR and scanning electron microscopy (SEM. The results showed first order kinetics with respect to the anhydride. The maleinizated castor oil (MACO increased the mechanical resistance of the foam due to the greater interweaving by the incorporation of acid groups.

Thermally insulating and fire-retardant lightweight anisotropic foams based on nanocellulose and graphene oxide

Science.gov (United States)

Wicklein, Bernd; Kocjan, Andraž; Salazar-Alvarez, German; Carosio, Federico; Camino, Giovanni; Antonietti, Markus; Bergström, Lennart

2015-03-01

High-performance thermally insulating materials from renewable resources are needed to improve the energy efficiency of buildings. Traditional fossil-fuel-derived insulation materials such as expanded polystyrene and polyurethane have thermal conductivities that are too high for retrofitting or for building new, surface-efficient passive houses. Tailored materials such as aerogels and vacuum insulating panels are fragile and susceptible to perforation. Here, we show that freeze-casting suspensions of cellulose nanofibres, graphene oxide and sepiolite nanorods produces super-insulating, fire-retardant and strong anisotropic foams that perform better than traditional polymer-based insulating materials. The foams are ultralight, show excellent combustion resistance and exhibit a thermal conductivity of 15 mW m-1 K-1, which is about half that of expanded polystyrene. At 30 °C and 85% relative humidity, the foams retained more than half of their initial strength. Our results show that nanoscale engineering is a promising strategy for producing foams with excellent properties using cellulose and other renewable nanosized fibrous materials.

Measurement of polyurethane foam - air partition coefficients for semivolatile organic compounds as a function of temperature: Application to passive air sampler monitoring.

Science.gov (United States)

Francisco, Ana Paula; Harner, Tom; Eng, Anita

2017-05-01

Polyurethane foam - air partition coefficients (K PUF-air ) for 9 polycyclic aromatic hydrocarbons (PAHs), 10 alkyl-substituted PAHs, 4 organochlorine pesticides (OCPs) and dibenzothiophene were measured as a function of temperature over the range 5 °C-35 °C, using a generator column approach. Enthalpies of PUF-to-air transfer (ΔH PUF-air , kJ/mol) were determined from the slopes of log K PUF-air versus 1000/T (K), and have an average value of 81.2 ± 7.03 kJ/mol. The log K PUF-air values at 22 °C ranged from 4.99 to 7.25. A relationship for log K PUF-air versus log K OA was shown to agree with a previous relationship based on only polychlorinated biphenyls (PCBs) and derived from long-term indoor uptake study experiments. The results also confirm that the existing K OA -based model for predicting log K PUF-air values is accurate. This new information is important in the derivation of uptake profiles and effective air sampling volumes for PUF disk samplers so that results can be reported in units of concentration in air. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

On-line preconcentration system using a minicolumn of polyurethane foam loaded with Me-BTABr for zinc determination by Flame Atomic Absorption Spectrometry

International Nuclear Information System (INIS)

Azevedo Lemos, Valfredo; Nei Lopes dos Santos, Walter; Silva Santos, Juracir; Bezerra de Carvalho, Marcilio

2003-01-01

In the present paper, an on-line system for preconcentration and determination of zinc by Flame Atomic Absorption Spectrometry (FAAS) is proposed. It is based in the sorption of zinc(II) ions on a minicolumn packed with polyurethane foam loaded with 2-[2'-(6-methyl-benzothiazolylazo)]-4-bromophenol (Me-BTABr) reagent. Chemical and flow variables as pH effect, sample flow rate and eluent concentration were optimized using univariate methodology. The results demonstrated that zinc can determinate using the sample pH in the range of 6.5-9.2, sample flow rate of 6.0 ml min -1 , and the elution step using 0.10 mol l -1 hydrochloric acid solution at flow rate of 5.5 ml min -1 . In these conditions, an enrichment factor of 23 and a sampling rate of 48 samples per hour were achieved. The detection limit (DL, 3σ) as IUPAC recommendation was 0.37 μg l -1 and the precision (assessed as the relative standard deviation, R.S.D.) reached values of 5.9-1.8% in zinc solutions of 1.0-10.0 μg l -1 concentration, respectively. The method was successfully applied to the determination of trace amounts of zinc in natural water samples from Salvador (Brazil)

A case for closed-loop recycling of post-consumer PET for automotive foams.

Science.gov (United States)

Bedell, Matthew; Brown, Matthew; Kiziltas, Alper; Mielewski, Deborah; Mukerjee, Shakti; Tabor, Rick

2018-01-01

Striving to utilize sustainable material sources, polyester polyols made via glycolysis and esterification of recycled polyethylene terephthalate (rPET) scrap were used to synthesize flexible polyurethane (PU) foams typically found in automotive interior applications. The objective of this endeavor was to ascertain if a closed-loop model could be established with the discarded PET feedstock. In five separate formulations, up to 50% of the total polyol content (traditionally derived from petroleum-based feedstock) was replaced with the afore-mentioned sustainable recycled polyols. These foams underwent mechanical, thermal, morphological, and physical characterization testing to determine feasibility for use in an automotive interior. Young's modulus, tensile stress at maximum load, tear resistance, and compression modulus all increased by combined averages of 121%, 67%, 32%, and 150% over the control petroleum-based formulation, respectively, in foams possessing 50% rPET polyol content. Thermal stability also increased with sustainable polyol content; thermogravimetric analysis showed that 50% mass loss temperature increased by an average of 20 °C in foams containing 30% recycled polyol. Properties of density and SAG factor remained within 5% of the control petroleum-based reference foams. After comparing these findings to traditional polyols, a compelling argument can be made for the use of post-consumer automotive and industrial feedstocks in developing high-performing interior automotive PU foams. Copyright © 2017 Elsevier Ltd. All rights reserved.

MECHANICAL STRENGTH ENHANCEMENT OF OPEN-CELL ALUMINA FOAMS USING OPTIMUM CONCENTRATION OF DEFLOCCULANT

Directory of Open Access Journals (Sweden)

A. Hadi

2015-06-01

Full Text Available Open-cell alumina foams were prepared using the appropriate alumina slurry and polyurethane sponge with linear pore density of approximately 14 pores per inch (ppi as a template by the replica method. The rheological studies showed that the optimum solid content for the slurries without deflocculants was 60 wt. %. In order to increase the slurry solid content, Tiron (1,2-dihydroxy-3,5-benzene disulfonic acid disodium salt was used as dispersant. To determine the optimum concentration of dispersant, the viscosity curves of alumina slurries containing different values of Tiron from 0 to 1.2 wt. % (based on dry material weight were studied. The optimum concentration of Tiron obtained for lowest viscosity was 0.8 wt. %. Thus, the solid content in the slurry could be increased from 60 to 66 wt. %. The effect of increase in the slurry solid content and the way it affects the foam structure and the mechanical strength were investigated. Microstructural observations of the foams show a significant reduction in macroscopic and microscopic defects in the foam struts when the slurry solid content is increased. Total porosity of the produced alumina foams prepared using slurries containing 60 and 66 wt. % solid are 83.3 and 80.4 %, respectively, while the compressive strength of the foams has increased from 1.33 to 3.24 MPa.

Morphologies, Processing and Properties of Ceramic Foams and Their Potential as TPS Materials

Science.gov (United States)

Stackpoole, Mairead; Simoes, Conan R.; Johnson, Sylvia M.

2002-01-01

The current research is focused on processing ceramic foams with compositions that have potential as a thermal protection material. The use of pre-ceramic polymers with the addition of sacrificial blowing agents or sacrificial fillers offers a viable approach to form either open or closed cell insulation. Our work demonstrates that this is a feasible method to form refractory ceramic foams at relatively low processing temperatures. It is possible to foam complex shapes then pyrolize the system to form a ceramic while retaining the shape of the unfired foam. Initial work focused on identifying suitable pre-ceramic polymers with desired properties such as ceramic yield and chemical make up of the pyrolysis product after firing. We focused on making foams in the Si system (Sic, Si02, Si-0-C), which is in use in current acreage TPS systems. Ceramic foams with different architectures were formed from the pyrolysis of pre-ceramic polymers at 1200 C in different atmospheres. In some systems a sacrificial polyurethane was used as the blowing agent. We have also processed foams using sacrificial fillers to introduce controlled cell sizes. Each sacrificial filler or blowing agent leads to a unique morphology. The effect of different fillers on foam morphologies and the characterization of these foams in terms of mechanical and thermal properties are presented. We have conducted preliminary arc jet testing on selected foams with the materials being exposed to typical re-entry conditions for acreage TPS and these results will be discussed. Foams processed using these approaches have bulk densities ranging from 0.15 to 0.9 g/cm3 and cell sizes ranging from 5 to 500 pm. Compression strengths ranged from 2 to 7 MPa for these systems. Finally, preliminary oxidation studies have been conducted on selected systems and will be discussed.

Creation of Polyurethane Injection Materials, Their Pilot-industrial Production, Development and Industrial Introduction of the Technology of Strengthening and Restoring the Operability of Damaged Constructions and Buildings

Directory of Open Access Journals (Sweden)

Marukha, V.І.

2015-01-01

Full Text Available Polyurethane and foam polyurethane fluid injection materials not conceding foreign analogues and technology technology of restoration and strengthening the operability of concrete and reinforced concrete structures and buildings damaged by cracks were developed. Normative and technical documentation on the injection materials and technological processes was created. The diagnosticrestoring complex for implementing the above technologies was designed, installed and utilized at the construction sites. The equipment is designed and manufactured; the technology of the research and industrial production of «A» and «B» components of injecting polyurethane materials is designed and developed. The pilot-scale batch is manufactured. Technological processes of preparation and application of the «A» and «B» componentsof the injecting materials in industrial conditions are worked out and implemented.

Validation of a Polyimide Foam Model for Use in Transmission Loss Applications

Science.gov (United States)

Hong, Kwanwoo; Bolton, J. Stuart; Cano, Roberto J.; Weiser, Erik S.; Jensen, Brian J.; Silcox, Rich; Howerton, Brian M.; Maxon, John; Wang, Tongan; Lorenzi, Tyler

2010-01-01

The work described in this paper was focused on the use of a new polyimide foam in a double wall sound transmission loss application. Recall that polyimide foams are functionally attractive, compared to polyurethane foams, for example, owing to their fire resistance. The foam considered here was found to have a flow resistivity that was too high for conventional acoustical applications, and as a result, it was processed by partial crushing to lower the flow resistivity into an acceptable range. Procedures for measuring the flow resistivity and Young s modulus of the material have been described, as was an inverse characterization procedure for estimating the remaining Biot parameters based on standing wave tube measurements of transmission loss and absorption coefficient. The inverse characterization was performed using a finite element model implementation of the Biot poro-elastic material theory. Those parameters were then used to predict the sound transmission loss of a double panel system lined with polyimide foam, and the predictions were compared with full-scale transmission loss measurements. The agreement between the two was reasonable, especially in the high and low frequency limits; however, it was found that the SEA model resulted in an under-prediction of the transmission loss in the mid-frequency range. Nonetheless, it was concluded that the performance of polyimide foam could be predicted using conventional poro-elastic material models and that polyimide foam may offer an attractive alternative to other double wall linings in certain situations: e.g., when fire resistance is a key issue. Future work will concentrate on reducing the density of the foam to values similar to those used in current aircraft sidewall treatments, and developing procedures to improve the performance of the foam in transmission loss applications.

Polyurethane foam loaded with SDS for the adsorption of cationic dyes from aqueous medium: Multivariate optimization of the loading process.

Science.gov (United States)

Robaina, Nicolle F; Soriano, Silvio; Cassella, Ricardo J

2009-08-15

This paper reports the development of a new procedure for the adsorption of four cationic dyes (Rhodamine B, Methylene Blue, Crystal Violet and Malachite Green) from aqueous medium employing polyurethane foam (PUF) loaded with sodium dodecylsulfate (SDS) as solid phase. PUF loading process was based on the stirring of 200mg PUF cylinders with acidic solutions containing SDS. The conditions for loading were optimized by response surface methodology (RSM) using a Doehlert design with three variables that were SDS and HCl concentrations and stirring time. Results obtained in the optimization process showed that the stirring time is not a relevant parameter in the PUF loading, evidencing that the transport of SDS from solution to PUF surface is fast. On the other hand, both SDS and HCl concentrations were important parameters causing significant variation in the efficiency of the resulting solid phase for the removal of dyes from solution. At optimized conditions, SDS and HCl concentrations were 4.0 x 10(-4) and 0.90 mol L(-1), respectively. The influence of stirring time was evaluated by univariate methodology. A 20 min stirring time was established in order to make the PUF loading process fast and robust without losing efficiency. The procedure was tested for the removal of the four cationic dyes from aqueous solutions and removal efficiencies always better than 90% were achieved for the two concentrations tested (2.0 x 10(-5) and 1.0 x 10(-4)mol L(-1)).

Foam topology. Bending versus stretching dominated architectures

International Nuclear Information System (INIS)

Deshpande, V.; Ashby, M.; Fleck, N.

2000-01-01

Cellular solids can deform by either the bending or stretching of the cell walls. While most cellular solids are bending-dominated, those that are stretching-dominated are much more weight-efficient for structural applications. In this study we have investigated the topological criteria that dictate the deformation mechanism of a cellular solid by analysing the rigidity (or otherwise) of pin-jointed frameworks comprising inextensional struts. We show that the minimum node connectivity for a special class of lattice structured materials to be stretching-dominated is 6 for 2D foams and 12 for 3D foams. Similarly, sandwich plates comprising of truss cores faced with planar trusses require a minimum node connectivity of 9 to undergo stretching-dominated deformation for all loading states. (author)

Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing

Energy Technology Data Exchange (ETDEWEB)

Grin, A. [Building Science Corporation, Somerville, MA (United States); Smegal, J. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

2013-10-01

Unvented roof strategies with open cell and closed cell spray polyurethane foam insulation sprayed to the underside of roof sheathing have been used since the mid-1990's to provide durable and efficient building enclosures. However, there have been isolated moisture related incidents reported anecdotally that raise potential concerns about the overall hygrothermal performance of these systems. This project involved hygrothermal modeling of a range of rainwater leakage and field evaluations of in-service residential roofs using spray foam insulation. All of the roof assemblies modeled exhibited drying capacity to handle minor rainwater leakage. All field evaluation locations of in-service residential roofs had moisture contents well within the safe range for wood-based sheathing. Explorations of eleven in-service roof systems were completed. The exploration involved taking a sample of spray foam from the underside of the roof sheathing, exposing the sheathing, then taking a moisture content reading. All locations had moisture contents well within the safe range for wood-based sheathing. One full-roof failure was reviewed, as an industry partner was involved with replacing structurally failed roof sheathing. In this case the manufacturer's investigation report concluded that the spray foam was installed on wet OSB based on the observation that the spray foam did not adhere well to the substrate and the pore structure of the closed cell spray foam at the ccSPF/OSB interface was indicative of a wet substrate.

Self-assembly of graft polyurethanes having both crystallizable poly({epsilon}-caprolactone) blocks and soft poly(n-butyl acrylate) segments

Energy Technology Data Exchange (ETDEWEB)

Ibarboure, E.; Baron, A.; Papon, E. [Laboratoire de Chimie des Polymeres Organiques (LCPO), CNRS, Universite Bordeaux I. 16, Avenue Pey Berland, 33607, Pessac-Cedex (France); Rodriguez-Hernandez, J., E-mail: jrodriguez@enscpb.f [Laboratoire de Chimie des Polymeres Organiques (LCPO), CNRS, Universite Bordeaux I. 16, Avenue Pey Berland, 33607, Pessac-Cedex (France)

2009-04-02

We report the self-assembly behavior of graft polyurethanes combining in its structure soft lateral poly(n-butyl acrylate) (PnBuA) chains with rigid and crystallizable polycaprolactone (PCL) segments. Segmented polyurethanes microphase separated into high-glass transition temperature PCL hard and low-glass transition temperature PnBuA soft domains. The variation of the microstructure as a function of the hard segment content (ratio hard to soft segments) within the structure has been studied by using atomic force microscopy. Additionally, the crystallization mechanism appeared to be directly related to the properties of the substrates forming parallel lamellar structures on hydrophilic substrates and perpendicular lamellae with hydrophobic substrates.

The effects of composition and sintering temperature on the silica foam fabricated by slurry method

International Nuclear Information System (INIS)

Baharom, Syazwani; Ahmad, Sufizar; Taib, Hariati; Muda, Rizamarhaiza

2016-01-01

Reticulated ceramic or open pore ceramic foam is a well-known material which exhibits extremely high porosities, with a significant degree of interconnectivity that makes them desirable in a wide range of applications. There were broad types of ceramic foam fabrication method such as polymeric sponge method, direct foaming, and starch consolidation. In this study, the slurry method has been chosen to fabricate Silica (SiO_2) foam. In this process, Polyurethane (PU) foam template was dipped into ceramic slurry and followed by drying and sintering to obtain foam which contains porosity in the range of 50% to 70%. The compositions of SiO_2 were varied starting from 55 wt.%, 60 wt.%, 65 wt.% and 70 wt.%. The samples of SiO_2 that have been dipped and dried were sintered at 900°C, 1000°C, 1100°C, and 1250°C. The sintered SiO_2 ceramic foam samples were characterized to observe their morphology, and physical properties. Thus, the microstructure of the SiO_2 ceramic foams samples was examined by Scanning Electron Microscopy (SEM), and Electron Dispersive Spectroscopy (EDS). Meanwhile, the physical properties of the SiO_2 ceramic foam samples such as the total porosity (%) and bulk density were determined using Archimedes method. It was found that the density of ceramic foam produced was in the range of 0.25 g/cm"3 up to 0.75 g/cm"3, whereas the level of porosity percentage was in the range of 61.81% to 82.18% with the size of open pore or window cells were in between 141 µm up to 626 µm.

High molecular weight polyurethanes and a polyurethane urea based on 1,4-butanediisocyanate

NARCIS (Netherlands)

Spaans, CJ; de Groot, JH; Dekens, FG; Pennings, AJ

New biomedical polyurethanes and a polyurethane urea based on epsilon-caprolactone and 1,4-butanediisocyanate have been developed. On degradation, only non-toxic products are produced. The polyurethane urea with poly(epsilon-caprolactone) soft segments and butanediisocyanate/butanediamine hard

Fully recoverable rigid shape memory foam based on copper-catalyzed azide-alkyne cycloaddition (CuAAC) using a salt leaching technique.

Science.gov (United States)

Alzahrani, Abeer A; Saed, Mohand; Yakacki, Christopher M; Song, Han Byul; Sowan, Nancy; Walston, Joshua J; Shah, Parag K; McBride, Matthew K; Stansbury, Jeffrey W; Bowman, Christopher N

2018-01-07

This study is the first to employ the use of the copper-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization to form a tough and stiff, porous material from a well-defined network possessing a high glass transition temperature. The effect of the network linkages formed as a product of the CuAAC reaction, i.e., the triazoles, on the mechanical behavior at high strain was evaluated by comparing the CuAAC foam to an epoxy-amine-based foam, which consisted of monomers with similar backbone structures and mechanical properties (i.e., T g of 115 °C and a rubbery modulus of 1.0 MPa for the CuAAC foam, T g of 125 °C and a rubbery modulus of 1.2 MPa for the epoxy-amine foam). When each foam was compressed uniformly to 80% strain at ambient temperature, the epoxy-amine foam was severely damaged after only reaching 70% strain in the first compression cycle with a toughness of 300 MJ/m 3 . In contrast, the CuAAC foam exhibited pronounced ductile behavior in the glassy state with three times higher toughness of 850 MJ/m 3 after the first cycle of compression to 80% strain. Additionally, when the CuAAC foam was heated above T g after each of five compression cycles to 80% strain at ambient temperature, the foam completely recovered its original shape while exhibiting a gradual decrease in mechanical performance over the multiple compression cycles. The foam demonstrated almost complete shape fixity and recovery ratios even through five successive cycles, indicative of "reversible plasticity", making it highly desirable as a glassy shape memory foams.

Short- and long-term releases of fluorocarbons from disposal of polyurethane foam waste

DEFF Research Database (Denmark)

Kjeldsen, Peter; Scheutz, Charlotte

2003-01-01

Several halocarbons having very high global warming or ozone depletion potentials have been used as a blowing agent (BA) for insulation foam in home appliances, such as refrigerators and freezers. Many appliances are shredded after the end of their useful life. Release experiments carried out in ...

Synthesis and Properties of Novel T-Type Polyurethanes Containing 2,5-Dioxynitrostilbenyl Group as a Nonlinear Optical Chromophore

International Nuclear Information System (INIS)

Lee, Ju Yeon; Lee, Won Jung; Park, Eun Ju; Bang, Han Bae; Rhee, Bum Ku; Jung, Chang Soo; Lee, Seung Mook; Lee, Jin Hyun

2003-01-01

Two approaches to minimize the randomization have been proposed. One is to use crosslinking method and the other is to use high T g polymers such as polyimides. Polyurethane matrix forms extensive hydrogen bond between urethane linkage and increases rigidity preventing the relaxation of induced dipoles. In this work we prepared new T-type polyurethanes containing dioxynitrostilbenyl group as a NLO-chromophore. We selected 2,5-dioxynitrostilbenyl group as NLO-chromophore because it will have a large dipole moment and is rather easy to synthesize. Furthermore 2,5-dioxynitrostilbenyl group constitutes a novel T-type NLO polyurthanes, in which the NLO chromophores are parts of polymer backbones. These T-type NLO polyurethanes are not shown in the literature. After confirming the structure of the resulting polymers we investigated the properties such as T g and second harmonic generation (SHG) activity (d 33 ). We now report the results of the initial phase of the work

A kinetic approach to modeling the manufacture of high density strucutral foam: Foaming and polymerization

Energy Technology Data Exchange (ETDEWEB)

Rao, Rekha R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Mondy, Lisa Ann [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Noble, David R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Brunini, Victor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Roberts, Christine Cardinal [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Long, Kevin Nicholas [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Soehnel, Melissa Marie [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Celina, Mathias C. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Wyatt, Nicholas B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Thompson, Kyle R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Tinsley, James

2015-09-01

We are studying PMDI polyurethane with a fast catalyst, such that filling and polymerization occur simultaneously. The foam is over-packed to tw ice or more of its free rise density to reach the density of interest. Our approach is to co mbine model development closely with experiments to discover new physics, to parameterize models and to validate the models once they have been developed. The model must be able to repres ent the expansion, filling, curing, and final foam properties. PMDI is chemically blown foam, wh ere carbon dioxide is pr oduced via the reaction of water and isocyanate. The isocyanate also re acts with polyol in a competing reaction, which produces the polymer. A new kinetic model is developed and implemented, which follows a simplified mathematical formalism that decouple s these two reactions. The model predicts the polymerization reaction via condensation chemis try, where vitrification and glass transition temperature evolution must be included to correctly predict this quantity. The foam gas generation kinetics are determined by tracking the molar concentration of both water and carbon dioxide. Understanding the therma l history and loads on the foam due to exothermicity and oven heating is very important to the results, since the kinetics and ma terial properties are all very sensitive to temperature. The conservation eq uations, including the e quations of motion, an energy balance, and thr ee rate equations are solved via a stabilized finite element method. We assume generalized-Newtonian rheology that is dependent on the cure, gas fraction, and temperature. The conservation equations are comb ined with a level set method to determine the location of the free surface over time. Results from the model are compared to experimental flow visualization data and post-te st CT data for the density. Seve ral geometries are investigated including a mock encapsulation part, two configur ations of a mock stru ctural part, and a bar geometry to

Microcellular injection molding process for producing lightweight thermoplastic polyurethane with customizable properties

Science.gov (United States)

Ellingham, Thomas; Kharbas, Hrishikesh; Manitiu, Mihai; Scholz, Guenter; Turng, Lih-Sheng

2018-03-01

A three-stage molding process involving microcellular injection molding with core retraction and an "out-of-mold" expansion was developed to manufacture thermoplastic polyurethane into lightweight foams of varying local densities, microstructures, and mechanical properties in the same microcellular injection molded part. Two stages of cavity expansion through sequential core retractions and a third expansion in a separate mold at an elevated temperature were carried out. The densities varied from 0.25 to 0.42 g/cm3 (77% to 62% weight reduction). The mechanical properties varied as well. Cyclic compressive strengths and hysteresis loss ratios, together with the microstructures, were characterized and reported.

Influence of Orientation and Radiative Heat Transfer on Aluminum Foams in Buoyancy-Induced Convection

Science.gov (United States)

Billiet, Marijn; De Schampheleire, Sven; Huisseune, Henk; De Paepe, Michel

2015-01-01

Two differently-produced open-cell aluminum foams were compared to a commercially available finned heat sink. Further, an aluminum plate and block were tested as a reference. All heat sinks have the same base plate dimensions of four by six inches. The first foam was made by investment casting of a polyurethane preform and has a porosity of 0.946 and a pore density of 10 pores per linear inch. The second foam is manufactured by casting over a solvable core and has a porosity of 0.85 and a pore density of 2.5 pores per linear inch. The effects of orientation and radiative heat transfer are experimentally investigated. The heat sinks are tested in a vertical and horizontal orientation. The effect of radiative heat transfer is investigated by comparing a painted/anodized heat sink with an untreated one. The heat flux through the heat sink for a certain temperature difference between the environment and the heat sink’s base plate is used as the performance indicator. For temperature differences larger than 30 ∘C, the finned heat sink outperforms the in-house-made aluminum foam heat sink on average by 17%. Furthermore, the in-house-made aluminum foam dissipates on average 12% less heat than the other aluminum foam for a temperature difference larger than 40 ∘C. By painting/anodizing the heat sinks, the heat transfer rate increased on average by 10% to 50%. Finally, the thermal performance of the horizontal in-house-made aluminum foam heat sink is up to 18% larger than the one of the vertical aluminum foam heat sink. PMID:28793601

Influence of Orientation and Radiative Heat Transfer on Aluminum Foams in Buoyancy-Induced Convection

Directory of Open Access Journals (Sweden)

Marijn Billiet

2015-10-01

Full Text Available Two differently-produced open-cell aluminum foams were compared to a commercially available finned heat sink. Further, an aluminum plate and block were tested as a reference. All heat sinks have the same base plate dimensions of four by six inches. The first foam was made by investment casting of a polyurethane preform and has a porosity of 0.946 and a pore density of 10 pores per linear inch. The second foam is manufactured by casting over a solvable core and has a porosity of 0.85 and a pore density of 2.5 pores per linear inch. The effects of orientation and radiative heat transfer are experimentally investigated. The heat sinks are tested in a vertical and horizontal orientation. The effect of radiative heat transfer is investigated by comparing a painted/anodized heat sink with an untreated one. The heat flux through the heat sink for a certain temperature difference between the environment and the heat sink’s base plate is used as the performance indicator. For temperature differences larger than 30 °C, the finned heat sink outperforms the in-house-made aluminum foam heat sink on average by 17%. Furthermore, the in-house-made aluminum foam dissipates on average 12% less heat than the other aluminum foam for a temperature difference larger than 40 °C. By painting/anodizing the heat sinks, the heat transfer rate increased on average by 10% to 50%. Finally, the thermal performance of the horizontal in-house-made aluminum foam heat sink is up to 18% larger than the one of the vertical aluminum foam heat sink.

The effects of composition and sintering temperature on the silica foam fabricated by slurry method

Energy Technology Data Exchange (ETDEWEB)

Baharom, Syazwani, E-mail: hd140001@siswa.uthm.edu.my; Ahmad, Sufizar, E-mail: sufizar@uthm.edu.my; Taib, Hariati, E-mail: hariati@uthm.edu.my; Muda, Rizamarhaiza, E-mail: hd130013@siswa.uthm.edu.my [Department of Material and Design Engineering, Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), 86400 Parit Raja, Batu Pahat, Johor (Malaysia)

2016-07-19

Reticulated ceramic or open pore ceramic foam is a well-known material which exhibits extremely high porosities, with a significant degree of interconnectivity that makes them desirable in a wide range of applications. There were broad types of ceramic foam fabrication method such as polymeric sponge method, direct foaming, and starch consolidation. In this study, the slurry method has been chosen to fabricate Silica (SiO{sub 2}) foam. In this process, Polyurethane (PU) foam template was dipped into ceramic slurry and followed by drying and sintering to obtain foam which contains porosity in the range of 50% to 70%. The compositions of SiO{sub 2} were varied starting from 55 wt.%, 60 wt.%, 65 wt.% and 70 wt.%. The samples of SiO{sub 2} that have been dipped and dried were sintered at 900°C, 1000°C, 1100°C, and 1250°C. The sintered SiO{sub 2} ceramic foam samples were characterized to observe their morphology, and physical properties. Thus, the microstructure of the SiO{sub 2} ceramic foams samples was examined by Scanning Electron Microscopy (SEM), and Electron Dispersive Spectroscopy (EDS). Meanwhile, the physical properties of the SiO{sub 2} ceramic foam samples such as the total porosity (%) and bulk density were determined using Archimedes method. It was found that the density of ceramic foam produced was in the range of 0.25 g/cm{sup 3} up to 0.75 g/cm{sup 3}, whereas the level of porosity percentage was in the range of 61.81% to 82.18% with the size of open pore or window cells were in between 141 µm up to 626 µm.

Manufacturing of Cast Metal Foams with Irregular Cell Structure

Directory of Open Access Journals (Sweden)

Kroupová I.

2015-06-01

Full Text Available Metallic foams are materials of which the research is still on-going, with the broad applicability in many different areas (e.g. automotive industry, building industry, medicine, etc.. These metallic materials have specific properties, such as large rigidity at low density, high thermal conductivity, capability to absorb energy, etc. The work is focused on the preparation of these materials using conventional casting technology (infiltration method, which ensures rapid and economically feasible method for production of shaped components. In the experimental part we studied conditions of casting of metallic foams with open pores and irregular cell structure made of ferrous and nonferrous alloys by use of various types of filler material (precursors.

Polyols from microwave liquefied bagasse and its application to rigid polyurethane foam

Science.gov (United States)

Jiulong Xie; Xianglin Zhai; Chung Hse; Todd Shupe; Hui Pan

2015-01-01

Bagasse flour (BF) was liquefied using bi-component polyhydric alcohol (PA) as a solventand phosphoric acid as a catalyst in a microwave reactor. The effect of BF to solvent ratio andreaction temperatures on the liquefaction extent and characteristics of liquefied products wereevaluated. The results revealed that almost 75% of the...

Materials for District Heating Pipes

DEFF Research Database (Denmark)

Nielsen, Lars Valentin

A model for the thermal conductivity of closed cell polyurethane foam is deduced for foams with density lower than 120 kg/m3.......A model for the thermal conductivity of closed cell polyurethane foam is deduced for foams with density lower than 120 kg/m3....

Preparation and characterization of starch-based loose-fill packaging foams

Science.gov (United States)

Fang, Qi

Regular and waxy corn starches were blended in various ratios with biodegradable polymers including polylactic acid (PLA), Eastar Bio Copolyester 14766 (EBC) and Mater-Bi ZF03U (MBI) and extruded with a C. W. Brabender laboratory twin screw extruder using a 3-mm die nozzle at 150°C and 150 rev/min. Physical characteristics including radial expansion, unit density and bulk density and water solubility index, water absorption characteristics, mechanical properties including compressibility, Young's modulus, spring index, bulk compressibility and bulk spring index and abrasion resistance were investigated as affected by the ingredient formulations, i.e. type of polymers, type of starches, polymer to starch ratio and starch moisture content. A completely randomized factorial blocking experimental design was used. Fifty-four treatments resulted. Each treatment was replicated three times. SAS statistical software package was used to analyze the data. Foams made of waxy starch had better radial expansion, lower unit density and bulk density than did foams made of regular starch. Regular starch foams had significantly lower water solubility index than did the waxy starch foams. PLA-starch foams had the lowest compressibility and Young's modulus. MBI-starch foams were the most rigid. All foams had excellent spring indices and bulk spring indices which were comparable to the spring index of commercial expanded polystyrene foam. Correlations were established between the foam mechanical properties and the physical characteristics. Foam compressibility and Young's modulus decreased as increases in radial expansion and decreases in unit and bulk densities. Their relationships were modeled with power law equations. No correlation was observed between spring index and bulk spring index and foam physical characteristics. MBI-starch foams had the highest equilibrium moisture content. EBC-starch and PLA-starch foams had similar water absorption characteristics. No significant

Polyurethane compounds having carbon nanotubes

NARCIS (Netherlands)

2010-01-01

The invention relates to semi-crystalline polyurethane (PUR) compositions filled with carbon nanotubes (CNT) and having improved electrical properties, which can be obtained on the basis of water-based polyurethane/CNT mixtures. The invention further relates to a method for producing polyurethane

21 CFR 177.1680 - Polyurethane resins.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyurethane resins. 177.1680 Section 177.1680 Food... of Single and Repeated Use Food Contact Surfaces § 177.1680 Polyurethane resins. The polyurethane...) For the purpose of this section, polyurethane resins are those produced when one or more of the...

Mechanical and thermal property characterization of poly-L-lactide (PLLA) scaffold developed using pressure-controllable green foaming technology

International Nuclear Information System (INIS)

Sheng, Shen-Jun; Hu, Xiao; Wang, Fang; Ma, Qing-Yu; Gu, Min-Fen

2015-01-01

Poly-L-lactide (PLLA) is one of the most promising biological materials used for tissue engineering scaffolds (TES) because of their excellent biodegradability and tenability. Here, microcellular PLLA foams were fabricated by pressure-controllable green foaming technology. Scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), wide angle X-ray diffraction measurement (WAXRD), thermogravimetric (TG) analysis, reflection-Fourier transform infrared (FTIR) analysis, enzymatic degradation study and MTT assay were used to analyze the scaffolds' morphologies, structures and crystallinities, mechanical and biodegradation properties, as well as their cytotoxicity. The results showed that PLLA foams with pore sizes from 8 to 103 μm diameters were produced when the saturation pressure decreased from 7.0 to 4.0 MPa. Through a combination of StepScan DSC (SSDSC) and WAXRD approaches, it was observed in PLLA foams that the crystallinity, highly-oriented metastable state and rigid amorphous phase increased with the increasing foaming pressure. It was also found that both the glass transition temperature and apparent enthalpy of PLLA significantly increased after the foaming process, which suggested that the changes of microcellular structure could provide PLLA scaffolds better thermal stability and elasticity. Moreover, MTT assessments suggested that the smaller pore size should benefit cell attachment and growth in the scaffold. The results of current work will give us better understanding of the mechanisms involved in structure and property changes of PLLA at the molecular level, which enables more possibilities for the design of PLLA scaffold to satisfy various requirements in biomedical and green chemical applications. - Highlights: • Pressure-controllable green foaming technology is used. • The crystallinity and rigid amorphous fraction is calculated by using DSC and XRD. • We examine the changes of

Mechanical and thermal property characterization of poly-L-lactide (PLLA) scaffold developed using pressure-controllable green foaming technology

Energy Technology Data Exchange (ETDEWEB)

Sheng, Shen-Jun [Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023 (China); School of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023 (China); Hu, Xiao [Department of Physics and Astronomy, Rowan University, Glassboro, NJ 08028 (United States); Department of Biomedical and Translational Sciences, Rowan University, Glassboro, NJ 08028 (United States); Wang, Fang, E-mail: wangfang@njnu.edu.cn [Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023 (China); Department of Physics and Astronomy, Rowan University, Glassboro, NJ 08028 (United States); Ma, Qing-Yu [Key Laboratory of Optoelectronics of Jiangsu Province, School of Physics and Technology, Nanjing Normal University, Nanjing 210023 (China); Gu, Min-Fen [Center of Analysis and Testing, Nanjing Normal University, Nanjing 210023 (China)

2015-04-01

Poly-L-lactide (PLLA) is one of the most promising biological materials used for tissue engineering scaffolds (TES) because of their excellent biodegradability and tenability. Here, microcellular PLLA foams were fabricated by pressure-controllable green foaming technology. Scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), wide angle X-ray diffraction measurement (WAXRD), thermogravimetric (TG) analysis, reflection-Fourier transform infrared (FTIR) analysis, enzymatic degradation study and MTT assay were used to analyze the scaffolds' morphologies, structures and crystallinities, mechanical and biodegradation properties, as well as their cytotoxicity. The results showed that PLLA foams with pore sizes from 8 to 103 μm diameters were produced when the saturation pressure decreased from 7.0 to 4.0 MPa. Through a combination of StepScan DSC (SSDSC) and WAXRD approaches, it was observed in PLLA foams that the crystallinity, highly-oriented metastable state and rigid amorphous phase increased with the increasing foaming pressure. It was also found that both the glass transition temperature and apparent enthalpy of PLLA significantly increased after the foaming process, which suggested that the changes of microcellular structure could provide PLLA scaffolds better thermal stability and elasticity. Moreover, MTT assessments suggested that the smaller pore size should benefit cell attachment and growth in the scaffold. The results of current work will give us better understanding of the mechanisms involved in structure and property changes of PLLA at the molecular level, which enables more possibilities for the design of PLLA scaffold to satisfy various requirements in biomedical and green chemical applications. - Highlights: • Pressure-controllable green foaming technology is used. • The crystallinity and rigid amorphous fraction is calculated by using DSC and XRD. • We examine the changes of

Indoor air pollution evaluation with emphasize on HDI and biological assessment of HDA in the polyurethane factories.

Science.gov (United States)

Mirmohammadi, Mirtaghi; Hakimi Ibrahim, M; Ahmad, Anees; Kadir, Mohd Omar Abdul; Mohammadyan, M; Mirashrafi, S B

2010-06-01

Today, many raw materials used in factories may have a dangerous effect on the physiological system of workers. One of them which is widely used in the polyurethane factories is diisocyanates. These compounds are widely used in surface coatings, polyurethane foams, adhesives, resins, elastomers, binders, and sealants. Exposure to diisocyanates causes irritation to the skin, mucous membranes, eyes, and respiratory tract. Hexamethylene diamine (HDA) is metabolite of hexamethylene diisocyanate (HDI). It is an excretory material by worker's urine who is exposed to HDI. Around 100 air samples were collected from five defined factories by midget impinger which contained dimethyl sulfoxide absorbent as a solvent and tryptamine as reagent. Samples were analyzed by high-performance liquid chromatography with EC\\UV detector using NIOSH 5522 method of sampling. Also, 50 urine samples collected from workers were also analyzed using William's biological analysis method. The concentration of HDI into all air samples were more than 88 microg/m(3), and they have shown high concentration of pollutant in the workplaces in comparison with NIOSH standard, and all of the workers' urine were contaminated by HDA. The correlation and regression test were used to obtain statistical model for HDI and HDA, which is useful for the prediction of diisocyanates pollution situation in the polyurethane factories.

Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Lost Foam Thin Wall - Feasibility of Producing Lost Foam Castings in Aluminum and Magnesium Based Alloys

Energy Technology Data Exchange (ETDEWEB)

Fasoyinu, Yemi [CanmetMATERIALS; Griffin, John A. [University of Alabama - Birmingham

2014-03-31

With the increased emphasis on vehicle weight reduction, production of near-net shape components by lost foam casting will make significant inroad into the next-generation of engineering component designs. The lost foam casting process is a cost effective method for producing complex castings using an expandable polystyrene pattern and un-bonded sand. The use of un-bonded molding media in the lost foam process will impose less constraint on the solidifying casting, making hot tearing less prevalent. This is especially true in Al-Mg and Al-Cu alloy systems that are prone to hot tearing when poured in rigid molds partially due to their long freezing range. Some of the unique advantages of using the lost foam casting process are closer dimensional tolerance, higher casting yield, and the elimination of sand cores and binders. Most of the aluminum alloys poured using the lost foam process are based on the Al-Si system. Very limited research work has been performed with Al-Mg and Al-Cu type alloys. With the increased emphasis on vehicle weight reduction, and given the high-strength-to-weight-ratio of magnesium, significant weight savings can be achieved by casting thin-wall (≤ 3 mm) engineering components from both aluminum- and magnesium-base alloys.

Gamma radiation effects on polydimethylsiloxane rubber foams under different radiation conditions

Science.gov (United States)

Sui, H. L.; Liu, X. Y.; Zhong, F. C.; Li, X. Y.; Wang, L.; Ju, X.

2013-07-01

Polydimethylsiloxane rubber foams were irradiated by gamma ray under different radiation conditions designed by orthogonal design method. Compression set measurement, infrared attenuated total reflectance spectroscopy (ATR) and X-ray induced photoelectron spectroscopy (XPS) were used. Three aging factors' influence effects on the mechanical property and chemical structure were studied. It was found that among the three factors and the chosen levels, both properties were affected most by radiation dose, while radiation dose rate had no obvious influence on both properties. The stiffening of the rubber foams was caused by cross-linking reactions in the Si-CH3. At the same radiation dose, the rigidity of the foams irradiated in air was lower than that in nitrogen. When polydimethylsiloxane was irradiated at a high dose in sealed nitrogen atmosphere, carbon element distribution would be changed. Hydrocarbons produced by gamma ray in the sealed tube would make the carbon content in the skin-deep higher than that in the middle, which indicated that polydimethylsiloxane rubber foams storing in a sealed atmosphere filled with enough hydrocarbons should be helpful to extend the service life.

Gamma radiation effects on polydimethylsiloxane rubber foams under different radiation conditions

Energy Technology Data Exchange (ETDEWEB)

Sui, H.L. [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China); Institute of Chemical Materials, CAEP, Mianyang 621900 (China); Liu, X.Y.; Zhong, F.C. [Institute of Chemical Materials, CAEP, Mianyang 621900 (China); Li, X.Y. [Institute of Nuclear Physics and Chemistry, CAEP, Mianyang 621900 (China); Wang, L. [Institute of Chemical Materials, CAEP, Mianyang 621900 (China); Ju, X., E-mail: jux@ustb.edu.cn [Department of Physics, University of Science and Technology Beijing, Beijing 100083 (China)

2013-07-15

Polydimethylsiloxane rubber foams were irradiated by gamma ray under different radiation conditions designed by orthogonal design method. Compression set measurement, infrared attenuated total reflectance spectroscopy (ATR) and X-ray induced photoelectron spectroscopy (XPS) were used. Three aging factors’ influence effects on the mechanical property and chemical structure were studied. It was found that among the three factors and the chosen levels, both properties were affected most by radiation dose, while radiation dose rate had no obvious influence on both properties. The stiffening of the rubber foams was caused by cross-linking reactions in the Si–CH{sub 3}. At the same radiation dose, the rigidity of the foams irradiated in air was lower than that in nitrogen. When polydimethylsiloxane was irradiated at a high dose in sealed nitrogen atmosphere, carbon element distribution would be changed. Hydrocarbons produced by gamma ray in the sealed tube would make the carbon content in the skin-deep higher than that in the middle, which indicated that polydimethylsiloxane rubber foams storing in a sealed atmosphere filled with enough hydrocarbons should be helpful to extend the service life.

The influence of adhesive joint characteristics of the bonded samples of PUR-foam

Directory of Open Access Journals (Sweden)

Josef Pacovský

2011-01-01

Full Text Available Upholstered chairs and upholstered furniture in general, is largely produced primarily using PUR-foams, and it largely in the form of gluing several types of foam and himself on a firm surface - usually plywood or the agglomerated material – for the qualitative increase of upholstered furniture (including seating. Work deals with properties of the bond in connection with the influence on the final properties of the finished product, or even a change of functional properties in use over time. This work deals with: The influence of the characteristics of the adhesive used on samples bonded polyurethane foams. This work deals with properties of the bond in connection with an influence on the final properties of the finished product, or changes in functional properties when used at the time. The work is focused on: Effect of glue applied to the characteristics of the bonded samples of PUR foam. To determine the effects observed were used as the basis for the methodology based on the standard EN 1957, which was further modified as necessary. The results of the tests and conclusions can be stated that the incidence of bonded joints, ultimately, has a negligible effect on the resulting observed characteristics and therefore can cut and paste samples of smaller sizes into larger blocks without a fundamental change of the original features.

Polyurethane membranes for surgical gown applications

Science.gov (United States)

Ukpabi, Pauline Ozoemena

The Occupational Safety and Health Administration (OSHA) recently issued a directive requiring all employers to supply personnel protective equipment to employees who are at risk of exposure to blood or other potentially infectious body fluids. For the healthcare worker, a wide variety of surgical gowns is available commercially but there are concerns over their barrier effectiveness and/or wearer comfort. To successfully create a barrier fabric which combines resistance to fluid penetration with comfort, a complete understanding of the relationship between membrane structure and functional properties is required. In this study, we investigated the surface properties of hydrophilicity and hydrophobicity in polyurethane membranes intended for use in surgical gowns. The polyurethane membranes were grafted with side chains of varying lengths, polyethylene glycol (PEG) being used for the hydrophilic modifications and perfluoroalkyl compounds (a monofunctional acid and a difunctional amino alcohol) for the hydrophobic modifications. The hydrophilic treatment was intended to improve the comfort properties of monolithic membranes without adversely affecting their barrier properties. The hydrophobic treatment, on the other hand, was intended to improve the fluid repellency and hence barrier properties of microporous membranes without adversely affecting their comfort properties. Reflection infrared spectroscopy showed that fluorine was successfully grafted onto the polyurethane backbone during the hydrophobic modification, but was not sensitive enough to detect PEG grafting in leached polyethylene glycol-treated polyurethanes. X-ray photoelectron spectroscopy showed that the perfluoroalkylated polyurethanes contained up to 40% fluorine on their surfaces and the PEG-treated polyurethanes showed an increase in their C-O content over the unmodified polyurethane. Scanning electron microscopy not only showed that perfluoroalkylation yielded polyurethane membranes with very

Elastic-Plastic Behaviour of Ultrasonic Assisted Compression of Polyvinyl Chloride (PVC) Foam

Science.gov (United States)

Muhalim, N. A. D.; Hassan, M. Z.; Daud, Y.

2018-04-01

The present study aims to investigate the elastic-plastic behaviour of ultrasonic assisted compression of PVC closed-cell foam. A series of static and ultrasonic compression test of PVC closed-cell foam were conducted at a constant cross head speed of 30 mm/min on dry surface condition. For quasi-static test, specimen was compressed between two rigid platens using universal testing machine. In order to evaluate the specimen behavior under ultrasonic condition, specimen was placed between a specifically design double-slotted block horn and rigid platen. The horn was designed and fabricated prior to the test as a medium to transmit the ultrasonic vibration from the ultrasonic transducer to the working specimen. It was tuned to a frequency of 19.89 kHz in longitudinal mode and provided an average oscillation amplitude at 6 µm on the uppermost surface. Following, the characteristics of stress-strain curves for quasi-static and ultrasonic compression tests were analyzed. It was found that the compressive stress was significantly reduced at the onset of superimposed ultrasonic vibration during plastic deformation.

In situ observation of syntactic foams under hydrostatic pressure using X-ray tomography

International Nuclear Information System (INIS)

Lachambre, J.; Maire, E.; Adrien, J.; Choqueuse, D.

2013-01-01

Syntactic foams (hollow glass microspheres embedded in a polymeric matrix) are being used increasingly for the purpose of thermal insulation in ultradeep water. A better understanding of the damage mechanisms of these materials at the microsphere scale under such a hydrostatic loading condition is of prior importance in determining actual material limits, improving phenomenological modelling and developing novel formulations in the future. To achieve this goal, a study based on X-ray microtomography was performed on two syntactic foam materials (polypropylene and polyurethane matrix) and a standard foamed PP. A special set up has been designed in order to allow the X-ray microtomographic observation of the material during hydrostatic pressure loading using ethanol as the pressure fluid. Spatial resolution of (3.5 μm) 3 and in situ non-destructive scanning allowed a unique qualitative and quantitative analysis of the composite microstructure during stepwise isotropic compression by hydrostatic pressure up to 50 MPa. The collapse of weaker microspheres were observed during pressure increase and the damage parameters could be estimated. It is shown that the microspheres which are broken or the porosities which are close to the surface in the foamed PP are filled by a fluid (either the ethanol or the polymeric matrix itself). The hydrostatic pressure decreases the volume of the foam only slightly. In the PU matrix, ethanol diffusion is seen to induce swelling of the matrix, which is an unexpected phenomenon but reveals the high potential of X-ray microtomographic observation to improve diffusion analysis in complex media

Assessing levels and seasonal variations of current-use pesticides (CUPs) in the Tuscan atmosphere, Italy, using polyurethane foam disks (PUF) passive air samplers

International Nuclear Information System (INIS)

Estellano, Victor H.; Pozo, Karla; Efstathiou, Christos; Pozo, Katerine; Corsolini, Simonetta; Focardi, Silvano

2015-01-01

Polyurethane foam disks (PUF) passive air samplers (PAS) were deployed over 4 sampling periods of 3–5-months (≥ 1 year) at ten urban and rural locations throughout the Tuscany Region. The purpose was to assess the occurrence and seasonal variations of ten current-use pesticides (CUPs). PUF disk extracts were analyzed using GC–MS. The organophosphates insecticides; chlorpyrifos (3–580 pg m −3 ) and chlorpyrifos-methyl (below detection limit – to 570 pg m −3 ) presented the highest levels in air, and showed seasonal fluctuation coinciding with the growing seasons. The relative proportion urban/(urban + rural) ranged from 0.4 to 0.7 showing no differences between urban and rural concentrations. Air back trajectories analysis showed air masses passing over agricultural fields and potentially enhancing the drift of pesticides into the urban sites. This study represents the first information regarding CUPs in the atmosphere of Tuscany region using PAS-PUF disk. - Highlights: • Current use pesticides (CUPs) were detected in the atmosphere of Tuscany, Italy. • Chlorpyrifos showed the highest concentrations in air with seasonal patterns. • CUPs levels might be influenced by agricultural activities. • No differences were detected between Urban and Rural sites. • Air mass analysis indicated the monitoring sites are influenced by local sources. - Seasonality of CUPs was measured in Tuscany, Italy. Chlorpyrifos showed the highest values. Urban and rural sites showed no differences. Agricultural activities influence CUPs levels in air

Ceramic-like open-celled geopolymer foam as a porous substrate for water treatment catalyst

Science.gov (United States)

Kovářík, T.; Křenek, T.; Pola, M.; Rieger, D.; Kadlec, J.; Franče, P.

2017-02-01

This paper presents results from experimental study on microstructural and mechanical properties of geopolymer-based foam filters. The process for making porous ceramic-like geopolymer body was experimentally established, consists of (a) geopolymer paste synthesis, (b) ceramic filler incorporation, (c) coating of open-celled polyurethane foam with geopolymer mixture, (d) rapid setting procedure, (e) thermal treatment. Geopolymer paste was based on potassium silicate solution n(SiO2)/n(K2O)=1.6 and powder mixture of calcined kaolin and precipitated silica. Various types of ceramic granular filler (alumina, calcined schistous clay and cordierite) were tested in relation to aggregate gradation design and particle size distribution. The small amplitude oscillatory rheometry in strain controlled regime 0.01% with angular frequency 10 rad/s was applied for determination of rheology behavior of prepared mixtures. Thermal treatment conditions were applied in the temperature range 1100 - 1300 °C. The developed porous ceramic-like foam effectively served as a substrate for highly active nanoparticles of selected Fe+2 spinels. Such new-type of nanocomposite was tested as a heterogeneous catalyst for technological process of advanced oxidative degradation of resistive antibiotics occurring in waste waters.

Multi objective optimization of foam-filled circular tubes for quasi-static and dynamic responses

Directory of Open Access Journals (Sweden)

Fauzan Djamaluddin

Full Text Available AbstractFuel consumption and safety are currently key aspects in automobile design. The foam-filled thin-walled aluminium tube represents a potentially effective material for use in the automotive industry, due to its energy absorption capability and light weight. Multi-objective crashworthiness design optimization for foam-filled double cylindrical tubes is presented in this paper. The double structures are impacted by a rigid wall simulating quasi-static and dynamic loadings. The optimal parameters under consideration are the minimum peak crushing force and maximum specific energy absorption, using the non-dominated sorting genetic algorithm-II (NSGA-II technique. Radial basis functions (RBF and D-Optimal are adopted to determine the more complex crashworthiness functional objectives. The comparison is performed by finite element analysis of the impact crashworthiness characteristics in tubes under static and dynamic loads. Finally, the optimum crashworthiness performance of empty and foam-filled double tubes is investigated and compared to the traditional single foam-filled tube. The results indicate that the foam-filled double aluminium circular tube can be recommended for crashworthy structures.

40 CFR 761.60 - Disposal requirements.

Science.gov (United States)

2010-07-01

... hardening slurry consisting of cement, bentonite, or clay) or high density polyurethane foam. (B) PCB... hardening slurry-like cement, bentonite, or clay) or high density polyurethane foam (except that only cement...

Creep behaviour of polyurethanes applied in the offshore industry under dynamic service conditions

Energy Technology Data Exchange (ETDEWEB)

Aquino, Fabio G.; Sheldrake, Terry; Clevelario, Judimar; Pires, Fabio S. [Wellstream International S/A - Rio de Janeiro, RJ (Brazil)], e-mail: fabio.aquino@wellstream.com; Souza, Miguel L. [Newtech Ltda, Sao Carlos, SP (Brazil)

2011-07-01

The oil industry commonly uses flexible pipes to convey oil and gas from wells to platforms that move constantly due to weather and tidal conditions. In this scenario, polymeric components are required to transitioning between the flexible material of the pipelines to the rigid material of the platform; polyurethanes are versatile polymers suitable for performing such services. As this material is subjected to constant loading during working conditions, and it its durability is to be maintained for several decades, it is important to determine the material's creep properties that relate to deformation caused by constant loading, which can represent an indirect measurement of the material's lifetime. In this study, creep behaviour data on the polyurethane samples was collected and an asymmetrical and nonlinear behaviour was observed. Additionally the material presented a creep fracture line with points only above 150% of deformation, considerably exceeding maximum values for its service conditions, which is limited to 10% of deformation considering the worst loading case for design premises of the final artifact. (author)

Performance and methanogenic community of rotating disk reactor packed with polyurethane during thermophilic anaerobic digestion

International Nuclear Information System (INIS)

Yang, Yingnan; Tsukahara, Kenichiro; Sawayama, Shigeki

2007-01-01

A newly developed anaerobic rotating disk reactor (ARDR) packed with polyurethane was used in continuous mode for organic waste removal under thermophilic (55 o C) anaerobic conditions. This paper reports the effects of the rotational speed on the methanogenic performance and community in an ARDR supplied with acetic acid synthetic wastewater as the organic substrate. The best performance was obtained from the ARDR with the rotational speed (ω) of 30 rpm. The average removal of dissolved organic carbon was 98.5%, and the methane production rate was 393 ml/l-reactor/day at an organic loading rate of 2.69 g/l-reactor/day. Under these operational conditions, the reactor had a greater biomass retention capacity and better reactor performance than those at other rotational speeds (0, 5 and 60 rpm). The results of 16S rRNA phylogenetic analysis indicated that the major methanogens in the reactor belonged to the genus Methanosarcina spp. The results of real-time polymerase chain reaction (PCR) analysis suggested that the cell density of methanogenic archaea immobilized on the polyurethane foam disk could be concentrated more than 2000 times relative to those in the original thermophilic sludge. Scanning electron microphotographs showed that there were more immobilized microbes at ω of 30 rpm than 60 rpm. A rotational speed on the outer layer of the disk of 6.6 m/min could be appropriate for anaerobic digestion using the polyurethane ARDR

In-situ long-term thermal performance of impermeably face polyiso foam boards

Energy Technology Data Exchange (ETDEWEB)

Mukhopadhyaya, Phalguni; Normandin, Nicole; Van Reenen, David; Lackey, John [National Research Council Canada, Institute for Reserch in Construction, Ottawa, (Canada); Drouin, Michel [Consultant, Dorion, (Canada)

2010-07-01

Closed-cell polyisocyanurate (polyiso) foam insulation products are widely used in building envelope constructions as they have one of the highest R-values per unit thickness among the insulations used in the construction industry. The introduction of impermeable facers on the surface of polyiso rigid board is aimed at enhancing the long-term thermal resistance (LTTR) properties of the foam. This paper evaluated the thermal performance of impermeably faced polyiso boards after more than six years of field exposure. Boards were installed and instrumented at NRC-IRC's field test facility. Field monitoring was performed on a regular basis for six years of exposure until 2008. Then, nine specimens were cut from the boards which were removed from the test hut to evaluate their thermal characteristic using a heat flow meter apparatus. It was found that the impermeably faced polyiso foam insulation boards aged significantly.

40 CFR 721.8095 - Silylated polyurethane.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Silylated polyurethane. 721.8095... Substances § 721.8095 Silylated polyurethane. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a silylated polyurethane (PMN P-95-1356) is...

Thermal Expansion of Three Closed Cell Polymeric Foams at Cryogenic Temperatures

Science.gov (United States)

Stokes, Eric

2006-01-01

The Space Shuttle External Tank (ET) contains the liquid H2 fuel and liquid oxygen oxidizer and supplies them under pressure to the three space shuttle main engines (SSME) in the orbiter during lift-off and ascent. The ET thermal protection system consists of sprayed-on foam insulation and pre-molded ablator materials. The closed-cell foams are the external coating on the ET and are responsible for minimizing the amount of moisture that condenses out and freezes on the tank from the humid air in Florida while it is on the pad with cryogenic propellant awaiting launch. This effort was part of the overall drive to understand the behavior of these materials under use-conditions. There are four specially-engineered closed-cell foams used on the tank. The thermal expansion (contraction) of three of the polyurethane and polyisocyanurate foams were measured from -423 F (the temperature of liquid hydrogen) to 125 F under atmospheric conditions and under vacuum. One of them, NCFI 24-124, is a mechanically-applied material and covers the main acreage of the tank, accounting for 77 percent of the total foam used. Another, BX-265, is also a mechanically-applied and hand-sprayed material used on the tank's "closeout" areas. PDL 1034 is a hand-poured foam used for filling odd-shaped cavities in the tank, Measurements were made in triplicate in the three primary material directions in the case of the first two materials and the two primary material directions in the case of the last. Task 1 was developing the techniques for getting a uniform heating rate and minimizing axial and radial thermal gradients in the specimens. Temperature measurements were made at four locations in the specimens during this initial development phase of testing. Major challenges that were overcome include developing techniques for transferring the coolant, liquid helium (-452 F), from its storage container to the test facility with a minimal transfer of heat to the coolant and control of the heating

Forming foam structures with carbon foam substrates

Science.gov (United States)

Landingham, Richard L.; Satcher, Jr., Joe H.; Coronado, Paul R.; Baumann, Theodore F.

2012-11-06

The invention provides foams of desired cell sizes formed from metal or ceramic materials that coat the surfaces of carbon foams which are subsequently removed. For example, metal is located over a sol-gel foam monolith. The metal is melted to produce a metal/sol-gel composition. The sol-gel foam monolith is removed, leaving a metal foam.

40 CFR 721.8090 - Polyurethane polymer.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyurethane polymer. 721.8090 Section... Substances § 721.8090 Polyurethane polymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (P-94-47) is subject...

Axial Crushing and Energy Absorption of Empty and Foam Filled Jute-glass/ Epoxy Bi-tubes

Directory of Open Access Journals (Sweden)

Khalid Asad A.

2016-01-01

Full Text Available Experimental work on the axial crushing of empty and polyurethane foam filled bi-tubular composite cone-tube has been carried out. Hand lay-up method was used to fabricate the bi-tubes using woven roving glass, jute and hybrid jute-glass/epoxy materials. The tubes were of 56 mm diameter, and the cones top diameters were 65 mm. Cone semi-apical angles of 5°, 10°, 15°, 20° and 25° were examined. Height of 120 mm was maintained for all the fabricated specimens. Effects of material used, cone semi apical angle and foam filler on the load-displacement relation, maximum load, crush force efficiency, and the specific energy absorption and failure mode were investigated. Results show that the foam filler improved the progressive crushing process, increased the maximum load and the absorbed energy of the bi-tubes. The maximum crushing load and the specific energy absorption increased with increasing the cone semi apical angle up to 20° for the empty bi-tubes and up to 25° for the foam filled bi-tubes. Progressive failure mode with fiber and matrix cracking was observed at the top narrow side of the fractured bi-tubes as well as at the bottom surface of 20° and 25° cone semi-apical angle bi-tubes.

Neutron gauging to detect voids in polyurethane

International Nuclear Information System (INIS)

Tsang, F.Y.; Alger, D.M.; Brugger, R.M.

1978-01-01

Thermal-neutron radiography and fast-neutron gauging measurements were made to evaluate the feasibility of detecting voids in a polyurethane block placed between steel plates. This sandwich of polyurethane and steel simulates the walls of a canister being designed to hold explosive devices. The polyurethane would act as a shock absorber in the canister. A large fabrication cost saving would result by casting the polyurethane, but a nondestructive testing (NDT) method is needed to determine the uniformity of the polyurethane fill. The radiography measurements used a beam of thermal neutrons, while the gauging used filtered beams of 24 keV and fission spectrum neutrons. For the 83-mm-thick polyurethane and 130-mm-thick steel matrix, the thermal-neutron radiography was able to detect only those voids equal to about one-half the polyurethane thickness. The gauging detected voids in the path of the neutron beam of a few millimetres thickness in seconds to minutes. The gauging is feasible as an NDT method for the canister application

Attachment of inorganic moieties onto aliphatic polyurethanes

Directory of Open Access Journals (Sweden)

Eliane Ayres

2007-06-01

Full Text Available Polyurethanes have been used in a series of applications due basically to their versatility in terms of controlling the behavior by altering basically the type of reagents used. However, for more specific and advanced applications, such as in membranes, biomaterials and sensors, well-organized and defined chemical functionalities are necessary. In this work, inorganic functionalities were incorporated into aliphatic polyurethanes (PU having different macromolecular architectures. Polyurethanes were synthesized using a polyether diol and dicyclohexylmethane 4,4' diisocyanate (H12-MDI. Polyurethanes having carboxylic acid groups were also produced by introducing 2,2- bis (hydroxymethyl propionic acid in the polymerization process. Inorganic functionalities were inserted into polyurethanes by reacting isocyanate end capped chains with aminopropyltriethoxysilane followed by tetraethoxysilane. PU having carboxylic acid groups yielded transparent samples after the incorporation of inorganic entities, as an evidence of smaller and better dispersed inorganic entities in the polymer network. FTIR and swelling measurements showed that polyurethanes having carboxylic acid groups had inorganic domains less packed, condensed and cross-linked when compared to polyurethanes with no carboxylic acid groups. Results also suggested that the progressive incorporation of inorganic moieties in both types of polyurethanes occurred in regions previously activated with inorganic functionalities, instead of by the creation of new domains. The temperatures of thermal decomposition and glass transition were also shifted to higher temperatures when inorganic functionalities were incorporated into polyurethanes.

Foam, Foam-resin composite and method of making a foam-resin composite

Science.gov (United States)

Cranston, John A. (Inventor); MacArthur, Doug E. (Inventor)

1995-01-01

This invention relates to a foam, a foam-resin composite and a method of making foam-resin composites. The foam set forth in this invention comprises a urethane modified polyisocyanurate derived from an aromatic amino polyol and a polyether polyol. In addition to the polyisocyanurate foam, the composite of this invention further contains a resin layer, wherein the resin may be epoxy, bismaleimide, or phenolic resin. Such resins generally require cure or post-cure temperatures of at least 350.degree. F.

Developement of Spherical Polyurethane Beads

Institute of Scientific and Technical Information of China (English)

K. Maeda; H. Ohmori; H. Gyotoku

2005-01-01

@@ 1Results and Discussion We established a new method to produce the spherical polyurethane beads which have narrower distribution of particle size. This narrower distribution was achieved by the polyurethane prepolymer which contains ketimine as a blocked chain-extending agent. Firstly, the prepolymer is dispersed into the aqueous solution containing surfactant. Secondaly, water comes into the inside of prepolymer as oil phase. Thirdly, ketimine is hydrolyzed to amine, and amine reacts with prepolymer immediately to be polyurethane.Our spherical polyurethane beads are very suitable for automotive interior parts especially for instrument panel cover sheet producing under the slush molding method, because of good process ability, excellent durability to the sunlight and mechanical properties at low temperature. See Fig. 1 ,Fig. 2 and Fig. 3 (Page 820).

Size selective isocyanate aerosols personal air sampling using porous plastic foams

International Nuclear Information System (INIS)

Cong Khanh Huynh; Trinh Vu Duc

2009-01-01

As part of a European project (SMT4-CT96-2137), various European institutions specialized in occupational hygiene (BGIA, HSL, IOM, INRS, IST, Ambiente e Lavoro) have established a program of scientific collaboration to develop one or more prototypes of European personal samplers for the collection of simultaneous three dust fractions: inhalable, thoracic and respirable. These samplers based on existing sampling heads (IOM, GSP and cassettes) use Polyurethane Plastic Foam (PUF) according to their porosity to support sampling and separator size of the particles. In this study, the authors present an original application of size selective personal air sampling using chemical impregnated PUF to perform isocyanate aerosols capturing and derivatizing in industrial spray-painting shops.

mdFoam+: Advanced molecular dynamics in OpenFOAM

Science.gov (United States)

Longshaw, S. M.; Borg, M. K.; Ramisetti, S. B.; Zhang, J.; Lockerby, D. A.; Emerson, D. R.; Reese, J. M.

2018-03-01

This paper introduces mdFoam+, which is an MPI parallelised molecular dynamics (MD) solver implemented entirely within the OpenFOAM software framework. It is open-source and released under the same GNU General Public License (GPL) as OpenFOAM. The source code is released as a publicly open software repository that includes detailed documentation and tutorial cases. Since mdFoam+ is designed entirely within the OpenFOAM C++ object-oriented framework, it inherits a number of key features. The code is designed for extensibility and flexibility, so it is aimed first and foremost as an MD research tool, in which new models and test cases can be developed and tested rapidly. Implementing mdFoam+ in OpenFOAM also enables easier development of hybrid methods that couple MD with continuum-based solvers. Setting up MD cases follows the standard OpenFOAM format, as mdFoam+ also relies upon the OpenFOAM dictionary-based directory structure. This ensures that useful pre- and post-processing capabilities provided by OpenFOAM remain available even though the fully Lagrangian nature of an MD simulation is not typical of most OpenFOAM applications. Results show that mdFoam+ compares well to another well-known MD code (e.g. LAMMPS) in terms of benchmark problems, although it also has additional functionality that does not exist in other open-source MD codes.

Partitioning of elastic energy in open-cell foams under finite deformations

International Nuclear Information System (INIS)

Harb, Rani; Taciroglu, Ertugrul; Ghoniem, Nasr

2013-01-01

The challenges associated with the computational modeling and simulation of solid foams are threefold—namely, the proper representation of an intricate geometry, the capability to accurately describe large deformations, and the extremely arduous numerical detection and enforcement of self-contact during crushing. The focus of this study is to assess and accurately quantify the effects of geometric nonlinearities (i.e. finite deformations, work produced under buckling-type motions) on the predicted mechanical response of open-cell foams of aluminum and polyurethane prior to the onset of plasticity and contact. Beam elements endowed with three-dimensional finite deformation kinematics are used to represent the foam ligaments. Ligament cross-sections are discretized through a fiber-based formulation that provides accurate information regarding the onset of plasticity, given the uniaxial yield stress–strain data for the bulk material. It is shown that the (hyper-) elastic energy partition within ligaments is significantly influenced by kinematic nonlinearities, which frequently cause strong coupling between the axial, bending, shear and torsional deformation modes. This deformation mode-coupling is uniquely obtained as a result of evaluating equilibrium in the deformed configuration, and is undetectable when small deformations are assumed. The relationship between the foam topology and energy partitioning at various stages of moderate deformation is also investigated. Coupled deformation modes are shown to play an important role, especially in perturbed Kelvin structures where over 70% of the energy is stored in coupled axial-shear and axial-bending modes. The results from this study indicate that it may not always be possible to accurately simulate the onset of plasticity (and the response beyond this regime) if finite deformation kinematics are neglected

Comparison of shape memory polymer foam versus bare metal coil treatments in an in vivo porcine sidewall aneurysm model.

Science.gov (United States)

Horn, John; Hwang, Wonjun; Jessen, Staci L; Keller, Brandis K; Miller, Matthew W; Tuzun, Egemen; Hartman, Jonathan; Clubb, Fred J; Maitland, Duncan J

2017-10-01

The endovascular delivery of platinum alloy bare metal coils has been widely adapted to treat intracranial aneurysms. Despite the widespread clinical use of this technique, numerous suboptimal outcomes are possible. These may include chronic inflammation, low volume filling, coil compaction, and recanalization, all of which can lead to aneurysm recurrence, need for retreatment, and/or potential rupture. This study evaluates a treatment alternative in which polyurethane shape memory polymer (SMP) foam is used as an embolic aneurysm filler. The performance of this treatment method was compared to that of bare metal coils in a head-to-head in vivo study utilizing a porcine vein pouch aneurysm model. After 90 and 180 days post-treatment, gross and histological observations were used to assess aneurysm healing. At 90 days, the foam-treated aneurysms were at an advanced stage of healing compared to the coil-treated aneurysms and showed no signs of chronic inflammation. At 180 days, the foam-treated aneurysms exhibited an 89-93% reduction in cross-sectional area; whereas coiled aneurysms displayed an 18-34% area reduction. The superior healing in the foam-treated aneurysms at earlier stages suggests that SMP foam may be a viable alternative to current treatment methods. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1892-1905, 2017. © 2016 Wiley Periodicals, Inc.

Sustained Release Drug Delivery Applications of Polyurethanes

Directory of Open Access Journals (Sweden)

Michael B. Lowinger

2018-05-01

Full Text Available Since their introduction over 50 years ago, polyurethanes have been applied to nearly every industry. This review describes applications of polyurethanes to the development of modified release drug delivery. Although drug delivery research leveraging polyurethanes has been ongoing for decades, there has been renewed and substantial interest in the field in recent years. The chemistry of polyurethanes and the mechanisms of drug release from sustained release dosage forms are briefly reviewed. Studies to assess the impact of intrinsic drug properties on release from polyurethane-based formulations are considered. The impact of hydrophilic water swelling polyurethanes on drug diffusivity and release rate is discussed. The role of pore formers in modulating drug release rate is examined. Finally, the value of assessing mechanical properties of the dosage form and approaches taken in the literature are described.

Antibacterial potency of V.A.C. GranuFoam Silver(®) Dressing.

Science.gov (United States)

Sachsenmaier, Saskia; Peschel, Andreas; Ipach, Ingmar; Kluba, Torsten

2013-10-01

V.A.C.(®) GranuFoam™ therapy is regularly used in the surgical therapy of infected wounds and soft tissue injuries. Silver nanoparticles can destroy bacterial cell walls and inhibit enzymes for cell replication. Silver dressings are therefore successfully used for many indications in wound therapy. In this study, we investigated the antimicrobial potency of ionic silver released from the silver-coated V.A.C.(®) GranuFoam™ during vacuum therapy. Silver dressing was exposed to agar plates populated with bacteria to measure silver release. A total of 15 agar plates colonised with either Staphylococcus aureus populations or with Staphylococcus epidermidis, were loaded with V.A.C. GranuFoam Silver(®) Dressing polyurethane foam (KCI, San Antonio, Texas). Each of 13 pieces of silver-coated foam was applied to an agar plate. Two plates were loaded with conventional black foam without any coating. After connecting to a vacuum pump, the vacuum therapy of the 15 plates lasted 5 days. The zone of inhibition of bacterial growth around the foam was measured daily. Silver release was also determined as a function of time. At each time point, there was evidence of silver in the agar independent of bacterial colonisation. The S. aureus agar showed a consecutive increase in silver concentration from baseline upon 48 h after exposure to the negative pressure of V.A.C. therapy. An increasing mean silver level after 48, 72 and 96 h was measured under V.A.C. therapy with a peak value after 120 h. In contrast, the results from the S. epidermidis plates did not follow a linear pattern. At the beginning of vacuum therapy, we documented a rise in silver concentration. After 48-96h, the silver levels fluctuated. A maximum zone of inhibition in both bacterial colonised plates (S. aureus and S. epidermidis) was found 39 h after the start of the V.A.C. GranuFoam Silver(®) therapy. From our results, we confirmed the antimicrobial effect of the silver ions against S. aureus and S

A complete process for the treatment of low level radioactive wastes using composite ion exchange resins based on polyurethane foam

International Nuclear Information System (INIS)

Rao, S.V.S.; Mani, A.G.S.; Lakshmi, R.; Sinha, P.K.

2007-01-01

The CFC-PU foam and HMO-PU foams have been employed for the removal of radioactive cesium and strontium respectively from actual Cat. III radioactive liquid waste received from reprocessing plant. Batch studies have been carried out in order to optimize the loading of above chemicals. The results of column and batch studies have indicated that there is a good agreement between them. After passing about 1000 bed volumes, the average DF and volume reduction factor obtained were 20 and 200 respectively. A method has been developed for the wet digestion of spent resins in alkaline KMnO 4 medium. The digested foam has been immobilized in cement matrix and the matrices were characterized with respect to compressive strength and leach resistance. (author)

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...

Defluoridation technology for drinking water and tea by green synthesized Fe3O4/Al2O3 nanoparticles coated polyurethane foams for rural communities.

Science.gov (United States)

Kumari, Sonu; Khan, Suphiya

2017-08-14

Fluoride (F) contaminated ground water poses a serious public health concern to rural population with unaffordable purification technologies. Therefore, development of a cost-effective, portable, environment and user-friendly defluoridation technique is imperative. In the present study, we report on the development of a green and cost-effective method that utilizes Fe 3 O 4 and Al 2 O 3 nanoparticles (NPs) that were synthesized using jojoba defatted meal. These NPs were impregnated on to polyurethane foam (PUF) and made into tea infusion bags. The Al 2 O 3 NPs-PUF displayed a higher water defluoridation capacity of 43.47 mg g -1 of F as compared to 34.48 mg g -1 of F with Fe 3 O 4 NPs-PUF. The synthesized Al 2 O 3 -PUF infusion bags removed the F that was under the permissible limit of 1.5 mg L -1 . The sorption experiments were conducted to verify the effect of different parameters such as pH, contact time, size of PUF and initial F concentration. The different properties of adsorbent were characterized using a combination of FESEM, EDX, XRD and FTIR techniques, respectively. The calculated total cost per NPs-PUF pouch developed is as low as US $0.05, which makes the technology most suitable for rural communities. This paper will be beneficial for researchers working toward further improvement in water purification technologies.

Evaluation of model parameters for growth, tannic acid utilization and tannase production in Bacillus gottheilii M2S2 using polyurethane foam blocks as support.

Science.gov (United States)

Selvaraj, Subbalaxmi; Vytla, Ramachandra Murty

2017-10-01

Production of tannase from B. gottheilii M2S2 was studied under solid-state fermentation with an optimized medium consisting of polyurethane foam matrix of dimension 40 × 40 × 5 mm, impregnated with a liquid medium comprising (w/v): 4% tannic acid; 2% NH 4 NO 3 ; 0.1% KH 2 PO 4 ; 0.2% MgSO 4 ; 0.1% NaCl and 0.05% CaCl 2 ·2H 2 O in distilled water, having a pH of 4.7. Maximum tannase production of 56.87 U/L was obtained after 32 h of fermentation at 32 °C in static condition. This study deals with the evaluation of unstructured kinetic models to understand the behavior of biomass, tannase production and tannic acid degradation, with the fermentation time. The growth rate of B. gottheilii M2S2 was 0.0703 h -1 at 32 h of fermentation. Product ( Y x/s ) and biomass yield ( Y p/s ) coefficients were estimated as 1.77 U/g of tannic acid and 0.276 g of biomass/g of tannic acid. All the kinetic constants µ , α , β , m and n were evaluated using MATLAB 2015Rb program. The experimental and model-generated data showed a good correlation, which indicated that these models will describe tannase production and fermentation process.

A geometrically controlled rigidity transition in a model for confluent 3D tissues

Science.gov (United States)

Merkel, Matthias; Manning, M. Lisa

2018-02-01

The origin of rigidity in disordered materials is an outstanding open problem in statistical physics. Previously, a class of 2D cellular models has been shown to undergo a rigidity transition controlled by a mechanical parameter that specifies cell shapes. Here, we generalize this model to 3D and find a rigidity transition that is similarly controlled by the preferred surface area S 0: the model is solid-like below a dimensionless surface area of {s}0\\equiv {S}0/{\\bar{V}}2/3≈ 5.413 with \\bar{V} being the average cell volume, and fluid-like above this value. We demonstrate that, unlike jamming in soft spheres, residual stresses are necessary to create rigidity. These stresses occur precisely when cells are unable to obtain their desired geometry, and we conjecture that there is a well-defined minimal surface area possible for disordered cellular structures. We show that the behavior of this minimal surface induces a linear scaling of the shear modulus with the control parameter at the transition point, which is different from the scaling observed in particulate matter. The existence of such a minimal surface may be relevant for biological tissues and foams, and helps explain why cell shapes are a good structural order parameter for rigidity transitions in biological tissues.

Gallic Acid Production with Mouldy Polyurethane Particles Obtained from Solid State Culture of Aspergillus niger GH1.

Science.gov (United States)

Mata-Gómez, Marco; Mussatto, Solange I; Rodríguez, Raul; Teixeira, Jose A; Martinez, Jose L; Hernandez, Ayerim; Aguilar, Cristóbal N

2015-06-01

Gallic acid production in a batch bioreactor was evaluated using as catalytic material the mouldy polyurethane solids (MPS) obtained from a solid-state fermentation (SSF) bioprocess carried out for tannase production by Aspergillus niger GH1 on polyurethane foam powder (PUF) with 5 % (v/w) of tannic acid as inducer. Fungal biomass, tannic acid consumption and tannase production were kinetically monitored. SSF was stopped when tannase activity reached its maximum level. Effects of washing with distilled water and drying on the tannase activity of MPS were determined. Better results were obtained with dried and washed MPS retaining 84 % of the tannase activity. Maximum tannase activity produced through SSF after 24 h of incubation was equivalent to 130 U/gS with a specific activity of 36 U/mg. The methylgallate was hydrolysed (45 %) in an easy, cheap and fast bioprocess (30 min). Kinetic parameters of tannase self-immobilized on polyurethane particles were calculated to be 5 mM and 04.1 × 10(-2) mM/min for K M and V max, respectively. Results demonstrated that the MPS, with tannase activity, can be successfully used for the production of the antioxidant gallic acid from methyl-gallate substrate. Direct use of PMS to produce gallic acid can be advantageous as no previous extraction of enzyme is required, thus reducing production costs.

40 CFR 721.9959 - Polyurethane polymer (generic).

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polyurethane polymer (generic). 721... Substances § 721.9959 Polyurethane polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a polyurethane polymer (PMN P-01...

Biodegradable polyurethane nanocomposites containing dexamethasone for ocular route

Energy Technology Data Exchange (ETDEWEB)

Rodrigues da Silva, Gisele [Federal University of Sao Joao Del Rei, School of Pharmacy, Divinopolis, Minas Gerais (Brazil); Silva-Cunha, Armando da [Federal University of Minas Gerais, School of Pharmacy, Belo Horizonte, Minas Gerais (Brazil); Behar-Cohen, Francine [INSERM, Physiopathology of ocular diseases: Therapeutic innovations, Institut des Cordeliers, Paris (France); Laboratoire d' Innovations Therapeutiques, Fondation Rothschild, Paris (France); Universite Rene Descartes, Hotel Dieu University Hospital, Paris (France); Ayres, Eliane [Federal University of Minas Gerais, Department of Metallurgical and Materials Engineering, Belo Horizonte, Minas Gerais (Brazil); Orefice, Rodrigo L., E-mail: rorefice@demet.ufmg.br [Federal University of Minas Gerais, Department of Metallurgical and Materials Engineering, Belo Horizonte, Minas Gerais (Brazil)

2011-03-12

The treatment of posterior segment ocular diseases, such as uveitis, by using eye drops and oral drugs is usually not effective due to the body's natural barriers to drug penetration. In this study, ocular implants to treat uveitis were synthesized by incorporating dexamethasone acetate, an important type of corticoid used in the treatment of some uveitis, into a biodegradable polyurethane containi clay nanoparticles. Biodegradable polyurethane nanocomposites having poly(caprolactone) oligomers as soft segments were obtained by delaminating clay particles within a polyurethane aqueous dispersion. The drug was incorporated into the polymer by dispersing it in the waterborne polyurethane followed by a drying step. Nanoparticles derived from clay were demonstrated to be able to tailor the mechanical properties of polyurethanes to achieve values that can match the properties of ocular soft tissues. Infrared spectra (FTIR) showed that the presence of clay particles was able to change the microphase separation process typical of polyurethanes. X-ray diffraction and small angle x-ray scattering (SAXS) results were explored to show that the incorporation of both dexamethasone acetate and nanocomponents derived from clay led to a less defined two-phase polyurethane. The presence of clay nanoparticles increased the rate of drug release measured in vitro. Human retinal pigment epithelial cells (ARPE-19) were cultured in contact with polyurethanes and polyurethane nanocomposites, and the viability of them (evaluated by using MTT assay after 7 days) showed that no toxic components were released from polyurethanes containing no drugs during the test.

Biodegradable polyurethane nanocomposites containing dexamethasone for ocular route

International Nuclear Information System (INIS)

Rodrigues da Silva, Gisele; Silva-Cunha, Armando da; Behar-Cohen, Francine; Ayres, Eliane; Orefice, Rodrigo L.

2011-01-01

The treatment of posterior segment ocular diseases, such as uveitis, by using eye drops and oral drugs is usually not effective due to the body's natural barriers to drug penetration. In this study, ocular implants to treat uveitis were synthesized by incorporating dexamethasone acetate, an important type of corticoid used in the treatment of some uveitis, into a biodegradable polyurethane containi clay nanoparticles. Biodegradable polyurethane nanocomposites having poly(caprolactone) oligomers as soft segments were obtained by delaminating clay particles within a polyurethane aqueous dispersion. The drug was incorporated into the polymer by dispersing it in the waterborne polyurethane followed by a drying step. Nanoparticles derived from clay were demonstrated to be able to tailor the mechanical properties of polyurethanes to achieve values that can match the properties of ocular soft tissues. Infrared spectra (FTIR) showed that the presence of clay particles was able to change the microphase separation process typical of polyurethanes. X-ray diffraction and small angle x-ray scattering (SAXS) results were explored to show that the incorporation of both dexamethasone acetate and nanocomponents derived from clay led to a less defined two-phase polyurethane. The presence of clay nanoparticles increased the rate of drug release measured in vitro. Human retinal pigment epithelial cells (ARPE-19) were cultured in contact with polyurethanes and polyurethane nanocomposites, and the viability of them (evaluated by using MTT assay after 7 days) showed that no toxic components were released from polyurethanes containing no drugs during the test.

A new selective chromogenic reagent for the spectrophotometric determination of thallium(I) and (III) and its separation using flotation and the solid-phase extraction on polyurethane foam.

Science.gov (United States)

Abou-El-Sherbini, Khaled S; Mostafa, Gamal A E; Hassanien, Mohamed M

2003-09-01

A new sensitive chromogenic reagent, 9,10-phenanthaquinone monoethylthiosemicarbazone (PET), has been synthesized and used in the spectrophotometric determination of Tl(III). In HNO3, H2SO4 or H3PO4 acids, PET can react immediately at room temperature with Tl(III) to form a red 2:1 complex with a maximum absorption at 516 nm. The different analytical parameters affecting the extraction and determination processes have been examined. The calibration curve was found to be linear over the range 0.2-10 microg cm(-3) with a molar absorptivity of 2.2 x 10(4) dm3 mol(-1) cm(-1). Sandell's sensitivity was found to be 0.0093 microg cm(-2). No interference from macroamounts of foreign ions was detected, except for Pd(II). However, Pd(II) does not affect the determination process, because its complex with PET has its lambda(max) at 625 nm. The proposed method has been applied to the determination of Tl(I and III) in synthetic and natural samples after separation by flotation (in oleic acid/kerosene) and solid-phase extraction (on polyurethane foam) techniques. The two methods were found to be accurate and not subject to random error, but solid-phase extraction was preferred because it is cheap, simpler and there is no contamination risk coming from flotation reagents.

Ultra Low Density Shape Memory Polymer Foams With Tunable Physicochemical Properties for Treatment of intracranial Aneurysms

Energy Technology Data Exchange (ETDEWEB)

Singhal, Pooja [Texas A & M Univ., College Station, TX (United States)

2013-12-01

Shape memory polymers (SMPs) are a rapidly emerging class of smart materials that can be stored in a deformed temporary shape, and can actively return to their original shape upon application of an external stimulus such as heat, pH or light. This behavior is particularly advantageous for minimally invasive biomedical applications comprising embolic/regenerative scaffolds, as it enables a transcatheter delivery of the device to the target site. The focus of this work was to exploit this shape memory behavior of polyurethanes, and develop an efficient embolic SMP foam device for the treatment of intracranial aneurysms.In summary, this work reports a novel family of ultra low density polymer foams which can be delivered via a minimally invasive surgery to the aneurysm site, actuated in a controlled manner to efficiently embolize the aneurysm while promoting physiological fluid/blood flow through the reticulated/open porous structure, and eventually biodegrade leading to complete healing of the vasculature.

Polyurethane and alginate immobilized algal biomass for the removal of aqueous toxic metals

International Nuclear Information System (INIS)

Fry, I.V.; Mehlhorn, R.J.

1992-12-01

We describe the development of immobilized, processed algal biomass for use as an adsorptive filter in the removal of toxic metals from waste water. To fabricate an adsorptive filter from precessed biomass several crucial criteria must be met, including: (1) high metal binding capacity, (2) long term stability (both mechanical and chemical), (3) selectivity for metals of concern (with regard to ionic competition), (4) acceptable flow capacity (to handle large volumes in short time frames), (5) stripping/regeneration (to recycle the adsorptive filter and concentrate the toxic metals to manageable volumes). This report documents experiments with processed algal biomass (Spirulina platensis and Spirulina maxima) immobilized in either alginate gel or preformed polyurethane foam. The adsorptive characteristics of these filters were assessed with regard to the criteria listed above

The Use of Vacuum-Assisted Closure and GranuFoam Silver® Dressing in the Management of Diabetic Foot Ulcer.

Science.gov (United States)

Günal, Özgür; Tuncel, Umut; Turan, Aydin; Barut, Sener; Kostakoglu, Naci

2015-10-01

The aim of this retrospective study was to evaluate the efficacy of vacuum-assisted closure (VAC) and GranuFoam Silver® dressing (KCI, San Antonio, TX) compared with conventional GranuFoam® dressing in the management of diabetic foot ulcers. Twenty-one consecutive patients treated with conventional or silver-coated foam dressing were reviewed retrospectively. The wound duration was 6 mo. Group 1 (n=10) received conventional foam dressing (GranuFoam) and group 2 (n=11) received silver-coated foam dressing (GranuFoam Silver). The wound surface area, duration of treatment, bacteriology, and recurrence were compared between the groups. The mean age of the patients was 61.70±10.52 y in group 1 and 67.27±11.28 y in group 2. In group 1, the average surface area of the wounds was 45.30±46.96 cm2 and 18.40±23.48 cm2 in the pre-treatment and post-treatment periods, respectively. There was a statistically significant difference between two measurements (p=0.005). Average duration of the treatment was 25.50±27.13 d in this group. In group 2, average surface area of the wounds in the pre-treatment and post-treatment periods were 41.55±36.03 cm2 and 7.64±3.91 cm2, respectively. There was a statistically significant difference between two measurements (p=0.003). Average duration of the treatment was 10.09±3.51 d in this group. The patients treated with silver-impregnated polyurethane foam dressing had reduced recurrence (2 vs. 7 wounds, p=0.030) and increased number of the culture-negative cases at the end of the treatment. With the results of the study, it was concluded that VAC GranuFoam silver dressing can be superior to conventional GranuFoam dressing in reducing the recurrence rate of infected diabetic foot ulcers.

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.

Associations between flame retardant applications in furniture foam, house dust levels, and residents' serum levels.

Science.gov (United States)

Hammel, Stephanie C; Hoffman, Kate; Lorenzo, Amelia M; Chen, Albert; Phillips, Allison L; Butt, Craig M; Sosa, Julie Ann; Webster, Thomas F; Stapleton, Heather M

2017-10-01

Polyurethane foam (PUF) in upholstered furniture frequently is treated with flame retardant chemicals (FRs) to reduce its flammability and adhere to rigorous flammability standards. For decades, a commercial mixture of polybrominated diphenyl ethers (PBDEs) called PentaBDE was commonly applied to foam to fulfill these regulations; however, concerns over toxicity, bioaccumulation, and persistence led to a global phase-out in the mid-2000s. Although PentaBDE is still detected in older furniture, other FR compounds such as tris(1,3-dichloroisopropyl) phosphate (TDCIPP) and Firemaster® 550 (FM550) have been increasingly used as replacements. While biomonitoring studies suggest exposure is widespread, the primary sources of exposure are not clearly known. Here, we investigated the relationships between specific FR applications in furniture foam and human exposure. Paired samples of furniture foam, house dust and serum samples were collected from a cohort in North Carolina, USA and analyzed for FRs typically used in PUF. In general, the presence of a specific FR in the sofa of a home was associated with an increase in the concentration of that FR in house dust. For example, the presence of PentaBDE in sofas was associated with significantly higher levels of BDE-47, a major component of PentaBDE, in house dust (10 β =6.4, phouse dust when FM550 was identified in the sofa foam (p<0.01). These relationships were modified by dust loading rates in the living room and the ratio of sofa size to room size. Interestingly, levels of TDCIPP and tris(1-chloro-2-isopropyl) phosphate (TCIPP) were also higher in dust with detections in sofa foam; however, these associations were not statistically significant and may suggest there are other prominent sources of these compounds in the home. In addition, the presence of PentaBDE in sofa foam was associated with significantly higher levels of BDE-47 in serum (p<0.01). These results suggest that FR applications in sofas are likely major

Development of polyisocyanurate pour foam formulation for space shuttle external tank thermal protection system

Science.gov (United States)

Harvey, James A.; Butler, John M.; Chartoff, Richard P.

1988-01-01

Four commercially available polyisocyanurate polyurethane spray-foam insulation formulations are used to coat the external tank of the space shuttle. There are several problems associated with these formulations. For example, some do not perform well as pourable closeout/repair systems. Some do not perform well at cryogenic temperatures (poor adhesion to aluminum at liquid nitrogen temperatures). Their thermal stability at elevated temperatures is not adequate. A major defect in all the systems is the lack of detailed chemical information. The formulations are simply supplied to NASA and Martin Marietta, the primary contractor, as components; Part A (isocyanate) and Part B (poly(s) and additives). Because of the lack of chemical information the performance behavior data for the current system, NASA sought the development of a non-proprietary room temperature curable foam insulation. Requirements for the developed system were that it should exhibit equal or better thermal stability both at elevated and cryogenic temperatures with better adhesion to aluminum as compared to the current system. Several formulations were developed that met these requirements, i.e., thermal stability, good pourability, and good bonding to aluminum.

Characterization and properties of sepiolite/polyurethane nanocomposites

International Nuclear Information System (INIS)

Chen Hongxiang; Zheng Maosheng; Sun Hongying; Jia Qingming

2007-01-01

In situ polymerization method is employed to prepare sepiolite/polyurethane nanocomposite. The morphology and the dispersion of sepiolite in polyurethane have been characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and Fourier transform infrared spectroscopy. The results show the sepiolite is dispersed homogeneously in the polyurethane matrix at a nanometer scale. The tensile test shows that the tensile strength and elongation at break for the nanocomposites increase with the addition of sepiolite as compared to those of the pure polyurethane. The TGA analysis reveals that the addition of nanofillers results in the higher thermal stability

Multiwall carbon nanotube embedded phenolic resin-based carbon foam for the removal of As (V) from contaminated water

Science.gov (United States)

Rani Agrawal, Pinki; Singh, Nahar; Kumari, Saroj; Dhakate, Sanjay R.

2018-03-01

It is well proposed that micron or nano size filters requires to separate adsorbent from water after removal of adsorbate. However, even after filtration trace quantity of adsorbent remains in purified water, which deteriorates the quality of water for potability. To overcome these problems, multi walled carbon nanotube (MWCNT) loaded Carbon Foam (CF) was fabricated by a sacrificial template process. In this process, multi walled carbon nanotubes (MWCNTs) and phenolic resin mixture was used for the impregnation of the polyurethane (PU) template. Impregnated PU Foam stabilized and carbonized to get MWCNTs embedded Carbon Foam (CF). The MWCNT loaded CF (MWCNTs-CF) was used for the removal of As (V) species from water. The proposed foam efficiently removes arsenic (As (V)) from water and it can be easily separated from water after purification without any sophisticated tools. The adsorption capacity of the proposed material was found to be 90.5 μg*g-1 at optimized condition of pH, time and concentration, which is excellent in comparison to several other materials utilized for removal of As (V). Kinetic and isotherm studies reveal that the multilayer adsorption over heterogeneous surface follows pseudo second order kinetics. The adsorption phenomena were further confirmed by several characterization techniques like scanning electron microscope (SEM), x-ray diffraction (XRD) spectroscopy and x-ray photoelectron spectroscopy (XPS).

Impact of foamed matrix components on foamed concrete properties

Science.gov (United States)

Tarasenko, V. N.

2018-03-01

The improvement of the matrix foam structure by means of foam stabilizing additives is aimed at solving the technology-oriented problems as well as at the further improvement of physical and mechanical properties of cellular-concrete composites. The dry foam mineralization is the mainstream of this research. Adding the concrete densifiers, foam stabilizers and mineral powders reduces the drying shrinkage, which makes the foam concrete products technologically effective.

Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold

International Nuclear Information System (INIS)

Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

2014-01-01

The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO 3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials. - Highlights: • The hydroxyapatite and silver nanoparticles were grown on the polyurethane scaffold • The hydroxyapatite/polyurethane acts as reducing agent, stabilizer and matrix for Ag • The samples were well characterized by SEM-EDX, XRD, XPS, UV-visible spectroscopy • The hydroxyapatite/silver polyurethane scaffold shows antibacterial property

77 FR 19861 - Certain Polybrominated Diphenylethers; Significant New Use Rule and Test Rule

Science.gov (United States)

2012-04-02

... of polyurethane foam (NAICS code 326150). Manufacturers of high impact polystyrene (HIPS) and... decided to phase out their activities with c-decaBDE. As a result, the sponsoring companies did not meet...) voluntary phased out their production in 2004. c-PentaBDE was used primarily in flexible polyurethane foams...

Estudo da sorção do corante catiônico violeta cristal por espuma de poliuretano em meio aquoso contendo dodecilsulfato de sódio Sorption of crystal violet by polyurethane foam from aqueous medium containing sodium dodecylsulfate

Directory of Open Access Journals (Sweden)

Mariana Mori

2009-01-01

Full Text Available This work presents a detailed study about the sorption of crystal violet (CV cationic dye onto polyether type polyurethane foam (PUF. The sorption process was based on the formation of an ionic-pair between cationic dye and dodecylsulfate anion (SDS, which presented high affinity by PUF. Set-up employed in the study was built up by adjusting a 200 mg cylinder of PUF to the arm of an overhead stirrer. The system was characterized in relation to equilibrium and kinetic aspects and it was modeled by employing Langmuir and Freundlich isotherms. Obtained results showed that the ratio between SDS and MB concentrations played an important role on the sorption process. According to results found it was possible to retain up to 3.4 mg of dye from 200 mL of a 5.0 x 10-5 mol L-1 CV solution containing 1.25 x 10-4 mol L-1 SDS, which represented a removal efficiency of around 92%.

FoamVis, A Visualization System for Foam Research: Design and Implementation

OpenAIRE

Lipsa, Dan; Roberts, Richard; Laramee, Robert

2015-01-01

Liquid foams are used in areas such as mineral separation, oil recovery, food and beverage production, sanitation and fire fighting. To improve the quality of products and the efficiency of processes in these areas, foam scientists wish to understand and control foam behaviour. To this end, foam scientists have used foam simulations to model foam behaviour; however, analysing these simulations presents difficult challenges. We describe the main foam research challenges and present the design ...

Physical and chemical evaluation of furniture waste briquettes.

Science.gov (United States)

Moreno, Ana Isabel; Font, Rafael; Conesa, Juan A

2016-03-01

Furniture waste is mainly composed of wood and upholstery foam (mostly polyurethane foam). Both of these have a high calorific value, therefore, energy recovery would be an appropriate process to manage these wastes. Nevertheless, the drawback is that the energy content of these wastes is limited due to their low density mainly that of upholstery foam. Densification of separate foam presents difficulties due to its elastic character. The significance of this work lies in obtaining densified material by co-densification of furniture wood waste and polyurethane foam waste. Densification of furniture wood and the co-densification of furniture wood waste with polyurethane foam have been studied. On the one hand, the parameters that have an effect on the quality of the furniture waste briquettes have been analysed, i.e., moisture content, compaction pressure, presence of lignin, etc. The maximum weight percentage of polyurethane foam that can be added with furniture wood waste to obtain durable briquettes and the optimal moisture were determined. On the other hand, some parameters were analysed in order to evaluate the possible effect on the combustion. The chemical composition of waste wood was compared with untreated wood biomass; the higher nitrogen content and the concentration of some metals were the most important differences, with a significant difference of Ti content. Copyright © 2016 Elsevier Ltd. All rights reserved.

Structure and Properties of Polyurethanes. Part 1,

Science.gov (United States)

1979-03-23

since the solidification of varnish coatings on basis it is polyurethane usually it occurs under conditions for contact wita moisture of air. Page...containing fluorine is polyurethane. In works (44, 84-86] is given the information about synthesis 11 DOC = 79011105 PAGE and special feature/peculiarities...of the phase transformations of the series/number of the fluorine -bedrlng aliphatic ones it is polyurethane. Page 87. In particular, were investigated

Study of ageing of polyurethanes applied to the offshore industry; Estudo do envelhecimento de poliuretanos aplicados na industria de petroleo

Energy Technology Data Exchange (ETDEWEB)

Aquino, Fabio G.; Sheldrake, Terry; Clevelario, Judimar; Pires, Fabio [Wellstream International, Rio de Janeiro, RJ (Brazil). Dept. de Tecnologia], email: fabio.aquino@wellstream.com; Coutinho, Fernanda M.B. [Universidade do Estado do Rio de Janeiro (IQ/UERJ), RJ (Brazil). Inst. de Quimica

2010-07-01

Brazil is worldwide renowned as a leader in oil and gas extraction in deep and ultra deep water. In the production chain, a great part of the oil and gas produced is conveyed through flexible pipelines that connect the production wells to the platforms. When the pipes are laid on the seabed in a static service condition, the flexible pipes are called flow lines and when raised from the seabed to the platform in a dynamic service condition, they are called risers. The pipes designed for dynamic applications are equipped with bend stiffeners, components with conical form and in general based on polyurethanes, which have the function of providing a transition between the structure of the pipes, of smooth stiffness, and the platform, extremely rigid. This work discussed the changes on the mechanical properties of polyurethanes due to hydrolysis under accelerated ageing. The specimens were exposed at 50, 60 and 70 deg C. The mass variation was also evaluated considering that these materials are designed for a service life exceeding twenty years. The polyurethanes presented significant degradation at 70 deg C, which can reduce its application time in the field owing to mechanical failures when subjected to high temperature. (author)

Glass transition in thermosetting clay-nanocomposite polyurethanes

Energy Technology Data Exchange (ETDEWEB)

Corcione, C. Esposito [Dipartimento di Ingegneria dell' Innovazione, Universita del Salento, Via Monteroni 73100, Lecce (Italy)], E-mail: carola.corcione@unile.it; Maffezzoli, A. [Dipartimento di Ingegneria dell' Innovazione, Universita del Salento, Via Monteroni 73100, Lecce (Italy)

2009-03-10

In this work nanocomposite in a polyurethane (PU) matrix, using an organically modified montmorillonite (OMM), were studied. An amount of organoclay ranging from 2% up to 6% by volume was added to the polyol component of the resin before mixing with isocyanate. The basal distance of OMM before and after mixing with the polyol and after curing was characterized by X-ray diffraction. The glass transition temperature (T{sub g}) of PU nanocomposites, measured using differential scanning calorimeter, increases with increasing the volume fraction of OMM. On the other hand, the heat capacity increment, {delta}C{sub p}, decreases from that the unfilled PU to that of the sample with 5.7 vol.% of OMM. Therefore the rigid amorphous fraction of the PU nanocomposites increases with increasing volume fraction of OMM. Finally, a three-phase model similar to that applied to study semi-crystalline polymers, was used to analyze the intercalation of the PU chains between OMM lamellae. The definition of molecular cooperativity was discussed for these systems and the characteristic length of the cooperative region was determined, using Donth equation.

POLYURETHANE COMPOSITES AS DRUG CARRIERS:: RELEASE PATTERNS

Directory of Open Access Journals (Sweden)

M. V. Grigoreva

2013-10-01

Full Text Available Biodegradable polyurethanes attract interest of those developing composite materials for biomedical applications. One of their features is their ability to serve as carriers, or matrixes, for medicines and other bioactive compounds to produce a therapeutic effect in body through targeted and/or prolonged delivery of these compounds in the process of their controlled release from matrix. The review presents polyurethane composites as matrices for a number of drugs. The relation between structure of the composites and their degradability both in vitro and in vivo and the dependence of drug release kinetics on physicochemical properties of polyurethane matrix are highlighted. The release of drugs (cefazolin, naltrexone and piroxicam from the composites based on cross-linked polyurethanes (synthesized from laprols, Mw between 1,500 and 2,000 Da and toluylene diisocyanate demonstrated more or less the same pattern (about 10 days in vitro and three to five days in vivo. In contrast, the composites with dioxydine based on a linear polyurethanes (synthesized from oligotetramethilene glycol, Mw 1,000 Da, diphenylmethane-4,4’-diisocyanate and 1,4-butanediol retained their antimicrobial activity at least 30 days. They also showed a significantly higher breaking strength as compared to that of the composites based on cross-linked polyurethanes.

Role of foam drainage in producing protein aggregates in foam fractionation.

Science.gov (United States)

Li, Rui; Zhang, Yuran; Chang, Yunkang; Wu, Zhaoliang; Wang, Yanji; Chen, Xiang'e; Wang, Tao

2017-10-01

It is essential to obtain a clear understanding of the foam-induced protein aggregation to reduce the loss of protein functionality in foam fractionation. The major effort of this work is to explore the roles of foam drainage in protein aggregation in the entire process of foam fractionation with bovine serum albumin (BSA) as a model protein. The results show that enhancing foam drainage increased the desorption of BSA molecules from the gas-liquid interface and the local concentration of desorbed molecules in foam. Therefore, it intensified the aggregation of BSA in foam fractionation. Simultaneously, it also accelerated the flow of BSA aggregates from rising foam into the residual solution along with the drained liquid. Because enhancing foam drainage increased the relative content of BSA molecules adsorbed at the gas-liquid interface, it also intensified the aggregation of BSA during both the defoaming process and the storage of the foamate. Furthermore, enhancing foam drainage more readily resulted in the formation of insoluble BSA aggregates. The results are highly important for a better understanding of foam-induced protein aggregation in foam fractionation. Copyright © 2017 Elsevier B.V. All rights reserved.

Polymer-Reinforced, Non-Brittle, Lightweight Cryogenic Insulation

Science.gov (United States)

Hess, David M.

2013-01-01

The primary application for cryogenic insulating foams will be fuel tank applications for fueling systems. It is crucial for this insulation to be incorporated into systems that survive vacuum and terrestrial environments. It is hypothesized that by forming an open-cell silica-reinforced polymer structure, the foam structures will exhibit the necessary strength to maintain shape. This will, in turn, maintain the insulating capabilities of the foam insulation. Besides mechanical stability in the form of crush resistance, it is important for these insulating materials to exhibit water penetration resistance. Hydrocarbon-terminated foam surfaces were implemented to impart hydrophobic functionality that apparently limits moisture penetration through the foam. During the freezing process, water accumulates on the surfaces of the foams. However, when hydrocarbon-terminated surfaces are present, water apparently beads and forms crystals, leading to less apparent accumulation. The object of this work is to develop inexpensive structural cryogenic insulation foam that has increased impact resistance for launch and ground-based cryogenic systems. Two parallel approaches will be pursued: a silica-polymer co-foaming technique and a post foam coating technique. Insulation characteristics, flexibility, and water uptake can be fine-tuned through the manipulation of the polyurethane foam scaffold. Silicate coatings for polyurethane foams and aerogel-impregnated polyurethane foams have been developed and tested. A highly porous aerogel-like material may be fabricated using a co-foam and coated foam techniques, and can insulate at liquid temperatures using the composite foam

Development of a impact limiter for radioactive material transport packages - characterization of the polymeric material used

International Nuclear Information System (INIS)

Mourao, Rogerio Pimenta; Mattar Neto, Miguel

2000-01-01

Impact limiters are sacrificial components widely used to protect radioactive waste packages against damages arising from falls, fires and collisions with protruding objects. Several materials have been used as impact limiter filling: wood, aluminum honeycomb, and metallic or polymeric foams. Besides, hollow structures are also used as shock absorbers, either as a single shell or as a tube array. One of the most popular materials among package designers is rigid polyurethane foam, owing to its toughness, workability, low specific weight, low costs and commercial availability. In Brazil, a foam developed using the polymer extracted from the castor oil plant (Ricinus communis) is being studied as a potential impact limiter filling. For a better performance of this material, it is necessary to minimize the impact limiter dimensions without compromising the package safety. For this, a detailed knowledge of the foam physical and mechanical properties is essential. A relatively vast amount of data about regular polymeric foams can be found in the literature and in foreign manufacturers brochures, but no data has been published about the properties of the castor oil foam. This paper presents data gathered in an ongoing research program aiming at the development of a Type-B packaging. Foam samples were submitted to uniaxial static compression tests and to hydrostatic tests. The results obtained reveal that the castor oil foam has a mechanical behavior similar to that of regular foams, with good property reproducibility and homogeneity. (author)

Generation of sclerosant foams by mechanical methods increases the foam temperature.

Science.gov (United States)

Tan, Lulu; Wong, Kaichung; Connor, David; Fakhim, Babak; Behnia, Masud; Parsi, Kurosh

2017-08-01

Objective To investigate the effect of agitation on foam temperature. Methods Sodium tetradecyl sulphate and polidocanol were used. Prior to foam generation, the sclerosant and all constituent equipment were cooled to 4-25℃ and compared with cooling the sclerosant only. Foam was generated using a modified Tessari method. During foam agitation, the temperature change was measured using a thermocouple for 120 s. Results Pre-cooling all the constituent equipment resulted in a cooler foam in comparison with only cooling the sclerosant. A starting temperature of 4℃ produced average foam temperatures of 12.5 and 13.2℃ for sodium tetradecyl sulphate and polidocanol, respectively. It was also found that only cooling the liquid sclerosant provided minimal cooling to the final foam temperature, with the temperature 20 and 20.5℃ for sodium tetradecyl sulphate and polidocanol, respectively. Conclusion The foam generation process has a noticeable impact on final foam temperature and needs to be taken into consideration when creating foam.

FoamVis, A Visualization System for Foam Research: Design and Implementation

Directory of Open Access Journals (Sweden)

Dan R. Lipsa

2015-03-01

Full Text Available Liquid foams are used in areas such as mineral separation, oil recovery, food and beverage production, sanitation and fire fighting. To improve the quality of products and the efficiency of processes in these areas, foam scientists wish to understand and control foam behaviour. To this end, foam scientists have used foam simulations to model foam behaviour; however, analysing these simulations presents difficult challenges. We describe the main foam research challenges and present the design of FoamVis, the only existing visualization, exploration and analysis application created to address them. We describe FoamVis’ main features, together with relevant design and implementation notes. Our goal is to provide a global overview and individual feature implementation details that would allow a visualization scientist to extend the FoamVis system with new algorithms and adapt it to new requirements. The result is a detailed presentation of the software that is not provided in previous visualization research papers.

Foaming and adsorption behavior of bovine and camel proteins mixed layers at the air/water interface.

Science.gov (United States)

Lajnaf, Roua; Picart-Palmade, Laetitia; Attia, Hamadi; Marchesseau, Sylvie; Ayadi, M A

2017-03-01

The aim of this work was to examine foaming and interfacial behavior of three milk protein mixtures, bovine α-lactalbumin-β-casein (M1), camel α-lactalbumin-β-casein (M2) and β-lactoglobulin-β-casein (M3), alone and in binary mixtures, at the air/water interface in order to better understand the foaming properties of bovine and camel milks. Different mixture ratios (100:0; 75:25; 50:50; 25:75; 0:100) were used during foaming tests and interfacial protein interactions were studied with a pendant drop tensiometer. Experimental results evidenced that the greatest foam was obtained with a higher β-casein amount in all camel and bovine mixtures. Good correlation was observed with the adsorption and the interfacial rheological properties of camel and bovine protein mixtures. The proteins adsorbed layers are mainly affected by the presence of β-casein molecules, which are probably the most abundant protein at interface and the most efficient in reducing the interfacial properties. In contrast of, the globular proteins, α-lactalbumin and β-lactoglobulin that are involved in the protein layer composition, but could not compact well at the interface to ensure foams creation and stabilization because of their rigid molecular structure. Copyright © 2016 Elsevier B.V. All rights reserved.

Novel route of synthesis for cellulose fiber-based hybrid polyurethane

Science.gov (United States)

Ikhwan, F. H.; Ilmiati, S.; Kurnia Adi, H.; Arumsari, R.; Chalid, M.

2017-07-01

Polyurethanes, obtained by the reaction of a diisocyanate compound with bifunctional or multifunctional reagent such as diols or polyols, have been studied intensively and well developed. The wide range modifier such as chemical structures and molecular weight to build polyurethanes led to designs of materials that may easily meet the functional product demand and to the extraordinary spreading of these materials in market. Properties of the obtained polymer are related to the chemical structure of polyurethane backbone. A number polyurethanes prepared from biomass-based monomers have been reported. Cellulose fiber, as a biomass material is containing abundant hydroxyl, promising material as chain extender for building hybrid polyurethanes. In previous researches, cellulose fiber was used as filler in synthesis of polyurethane composites. This paper reported a novel route of hybrid polyurethane synthesis, which a cellulose fiber was used as chain extender. The experiment performed by reacting 4,4’-Methylenebis (cyclohexyl isocyanate) (HMDI) and polyethylene glycol with variation of molecular weight to obtained pre-polyurethane, continued by adding micro fiber cellulose (MFC) with variation of type and composition in the mixture. The experiment was evaluated by NMR, FTIR, SEM and STA measurement. NMR and FTIR confirmed the reaction of the hybrid polyurethane. STA showed hybrid polyurethane has good thermal stability. SEM showed good distribution and dispersion of sorghum-based MFC.

Biopolymer foams - Relationship between material characteristics and foaming behavior of cellulose based foams

International Nuclear Information System (INIS)

Rapp, F.; Schneider, A.; Elsner, P.

2014-01-01

Biopolymers are becoming increasingly important to both industry and consumers. With regard to waste management, CO 2 balance and the conservation of petrochemical resources, increasing efforts are being made to replace standard plastics with bio-based polymers. Nowadays biopolymers can be built for example of cellulose, lactic acid, starch, lignin or bio mass. The paper will present material properties of selected cellulose based polymers (cellulose propionate [CP], cellulose acetate butyrate [CAB]) and corresponding processing conditions for particle foams as well as characterization of produced parts. Special focus is given to the raw material properties by analyzing thermal behavior (differential scanning calorimetry), melt strength (Rheotens test) and molecular weight distribution (gel-permeation chromatography). These results will be correlated with the foaming behavior in a continuous extrusion process with physical blowing agents and underwater pelletizer. Process set-up regarding particle foam technology, including extrusion foaming and pre-foaming, will be shown. The characteristics of the resulting foam beads will be analyzed regarding part density, cell morphology and geometry. The molded parts will be tested on thermal conductivity as well as compression behavior (E-modulus, compression strength)

Biopolymer foams - Relationship between material characteristics and foaming behavior of cellulose based foams

Science.gov (United States)

Rapp, F.; Schneider, A.; Elsner, P.

2014-05-01

Biopolymers are becoming increasingly important to both industry and consumers. With regard to waste management, CO2 balance and the conservation of petrochemical resources, increasing efforts are being made to replace standard plastics with bio-based polymers. Nowadays biopolymers can be built for example of cellulose, lactic acid, starch, lignin or bio mass. The paper will present material properties of selected cellulose based polymers (cellulose propionate [CP], cellulose acetate butyrate [CAB]) and corresponding processing conditions for particle foams as well as characterization of produced parts. Special focus is given to the raw material properties by analyzing thermal behavior (differential scanning calorimetry), melt strength (Rheotens test) and molecular weight distribution (gel-permeation chromatography). These results will be correlated with the foaming behavior in a continuous extrusion process with physical blowing agents and underwater pelletizer. Process set-up regarding particle foam technology, including extrusion foaming and pre-foaming, will be shown. The characteristics of the resulting foam beads will be analyzed regarding part density, cell morphology and geometry. The molded parts will be tested on thermal conductivity as well as compression behavior (E-modulus, compression strength).

Polyurethane doped with low-concentration erbium

NARCIS (Netherlands)

Ciobanu, C.; Stoica, E.; Cascaval, C.N.; Rosu, D.; Rosu, L.; State, M.; Emandi, A.; Nemes, I.; Petrescu, F.

2007-01-01

ABSTRACT: Polyurethane (PU) with lactate structures inits conformation can be used as a biological and biodegradablepolymer. Polyurethane lactate (PUL) was dopedwith small quantities of an erbium (Er3þ) complex, whichhindered the N¼N group. 2,20-Dihydroxyazobenzene wasused as a ligand for the Er3þ

INTERRUPTED IN-SITU COMPRESSIVE DEFORMATION EXPERIMENTS ON MMC FOAMS IN AN XCT: EXPERIMENTS AND ESTIMATION OF DISPLACEMENT FIELDS

Directory of Open Access Journals (Sweden)

Katharina Losch

2014-05-01

Full Text Available The mechanical properties of a metal-matrix composite foam are investigated by interrupted in-situ compressive deformation experiments within an X-ray computed tomography device (XCT. Each in-situ experiment generates a sequence of reconstructed 3D images of the foam microstructure. From these data, the deformation field is estimated by registring the images corresponding to three consecutive steps. To this end, the generic registration framework of the itk software suite is exploited and combined with several image preprocessing steps. Both segmented (binary images having just two grey values for foreground (strut structure and background (pore space and the result of the Euclidean distance transform (EDT on pore space and solid phase are used. The estimation quality is evaluated based on a sequence of synthetic data sets, where the foam’s microstructure is modelled by a random Laguerre tessellation. For large deformations, a combination of non-rigid registration for the EDT images and partwise-rigid registration on strongly deformed regions of the binary images, yields surprisingly small estimation errors.

Liquid foam templating - A route to tailor-made polymer foams.

Science.gov (United States)

Andrieux, Sébastien; Quell, Aggeliki; Stubenrauch, Cosima; Drenckhan, Wiebke

2018-06-01

Solid foams with pore sizes between a few micrometres and a few millimetres are heavily exploited in a wide range of established and emerging applications. While the optimisation of foam applications requires a fine control over their structural properties (pore size distribution, pore opening, foam density, …), the great complexity of most foaming processes still defies a sound scientific understanding and therefore explicit control and prediction of these parameters. We therefore need to improve our understanding of existing processes and also develop new fabrication routes which we understand and which we can exploit to tailor-make new porous materials. One of these new routes is liquid templating in general and liquid foam templating in particular, to which this review article is dedicated. While all solid foams are generated from an initially liquid(-like) state, the particular notion of liquid foam templating implies the specific condition that the liquid foam has time to find its "equilibrium structure" before it is solidified. In other words, the characteristic time scales of the liquid foam's stability and its solidification are well separated, allowing to build on the vast know-how on liquid foams established over the last 20 years. The dispersed phase of the liquid foam determines the final pore size and pore size distribution, while the continuous phase contains the precursors of the desired porous scaffold. We review here the three key challenges which need to be addressed by this approach: (1) the control of the structure of the liquid template, (2) the matching of the time scales between the stability of the liquid template and solidification, and (3) the preservation of the structure of the template throughout the process. Focusing on the field of polymer foams, this review gives an overview of recent research on the properties of liquid foam templates and summarises a key set of studies in the emerging field of liquid foam templating. It

Small bowel obstruction secondary to migration of a fragment of lithobezoar: a case report.

LENUS (Irish Health Repository)

Medani, Mekki

2009-01-01

INTRODUCTION: Small bowel obstruction is a common world-wide condition that has a range of etiological factors. The management is largely dependent on the cause of the obstruction. Small bowel obstruction caused by foreign body ingestion is rare; many items have been reported as responsible, but there are no reports implicating polyurethane foam. CASE PRESENTATION: We report the case of a 44-year-old Irish male who presented following ingestion of polyurethane foam. He was asymptomatic on presentation but developed a small bowel obstruction shortly thereafter. CONCLUSION: Patients presenting following ingestion of polyurethane foam should be scheduled for elective laparotomy, gastrotomy, and retrieval of the cast on the next available theatre list - given that they are suitable for surgery.

Electromagnetic absorber composite made of carbon fibers loaded epoxy foam for anechoic chamber application

International Nuclear Information System (INIS)

Méjean, Chloé; Pometcu, Laura; Benzerga, Ratiba; Sharaiha, Ala; Le Paven-Thivet, Claire; Badard, Mathieu; Pouliguen, Philippe

2017-01-01

Highlights: • Carbon fibers loaded epoxy foam composites are proposed as microwave absorbers. • Dielectric properties (ε′, tanδ) of composites increase with carbon fibers content and length. • S 11 coefficient of a pyramidal prototype was characterized in anechoic chamber. • Epoxy prototype shows better absorption performance than commercial absorber. • S 11 of the prototype is lower than −30 dB (4–18 GHz) at normal and oblique incidences. - Abstract: This paper presents a new electromagnetic absorbing material developed from carbon fibers loaded epoxy foam for an application in anechoic chamber. The composite was developed in order to replace the currently used pyramidal absorbers made of carbon particles loaded polyurethane foam. Epoxy-composites filled with different weight percentages (from 0 wt.% to 4 wt.%) and length (1 and 3 mm) of carbon fibers were achieved. After an optimization of the dispersion of carbon fibers in composite materials, the dielectric properties of the composites were measured using a coaxial-probe in the frequency range 4–18 GHz. Results have shown that the complex permittivity of the composites increases with the amount of charge and also with the length of the carbon fibers. Absorption performance of a prototype prepared with a low concentration (0.5 wt.%) of carbon fibers was measured in an anechoic chamber: it shows a mean gain of 10 dB compared to a commercial absorber.

Electromagnetic absorber composite made of carbon fibers loaded epoxy foam for anechoic chamber application

Energy Technology Data Exchange (ETDEWEB)

Méjean, Chloé; Pometcu, Laura [Institut d’Electronique et de Télécommunications de Rennes, 18 rue Henri Wallon, 22000 Saint-Brieuc (France); Benzerga, Ratiba, E-mail: ratiba.benzerga@univ-rennes1.fr [Institut d’Electronique et de Télécommunications de Rennes, 18 rue Henri Wallon, 22000 Saint-Brieuc (France); Sharaiha, Ala; Le Paven-Thivet, Claire; Badard, Mathieu [Institut d’Electronique et de Télécommunications de Rennes, 18 rue Henri Wallon, 22000 Saint-Brieuc (France); Pouliguen, Philippe [Département Recherche et Innovation Scientifique de la Direction Générale de l’Armement, 7-9 rue des Mathurins, 92221 Bagneux (France)

2017-06-15

Highlights: • Carbon fibers loaded epoxy foam composites are proposed as microwave absorbers. • Dielectric properties (ε′, tanδ) of composites increase with carbon fibers content and length. • S{sub 11} coefficient of a pyramidal prototype was characterized in anechoic chamber. • Epoxy prototype shows better absorption performance than commercial absorber. • S{sub 11} of the prototype is lower than −30 dB (4–18 GHz) at normal and oblique incidences. - Abstract: This paper presents a new electromagnetic absorbing material developed from carbon fibers loaded epoxy foam for an application in anechoic chamber. The composite was developed in order to replace the currently used pyramidal absorbers made of carbon particles loaded polyurethane foam. Epoxy-composites filled with different weight percentages (from 0 wt.% to 4 wt.%) and length (1 and 3 mm) of carbon fibers were achieved. After an optimization of the dispersion of carbon fibers in composite materials, the dielectric properties of the composites were measured using a coaxial-probe in the frequency range 4–18 GHz. Results have shown that the complex permittivity of the composites increases with the amount of charge and also with the length of the carbon fibers. Absorption performance of a prototype prepared with a low concentration (0.5 wt.%) of carbon fibers was measured in an anechoic chamber: it shows a mean gain of 10 dB compared to a commercial absorber.

Palm oil based polyols for acrylated polyurethane production

International Nuclear Information System (INIS)

Rida Tajau; Mohd Hilmi Mahmood; Mek Zah Salleh; Khairul Zaman Mohd Dahlan; Rosley Che Ismail

2006-01-01

Palm oil becomes important renewable resources for the production of polyols for the polyurethane manufacturing industry. The main raw materials used for the production of acrylated polyurethane are polyols, isocyanates and hydroxyl terminated acrylate compounds. In these studies, polyurethane based natural polymer (palm oil), i.e., POBUA (Palm Oil Based Urethane Acrylate) were prepared from three different types of palm oil based polyols i.e., epoxidised palm oil (EPOP), palm oil oleic acid and refined, bleached and deodorized (RBD) palm olein based polyols. The performances of these three acrylated polyurethanes when used for coatings and adhesives were determined and compared with each other. (Author)

Marine biofouling resistance of polyurethane with biodegradation and hydrolyzation.

Science.gov (United States)

Xu, Wentao; Ma, Chunfeng; Ma, Jielin; Gan, Tiansheng; Zhang, Guangzhao

2014-03-26

We have prepared polyurethane with poly(ε-caprolactone) (PCL) as the segments of the main chain and poly(triisopropylsilyl acrylate) (PTIPSA) as the side chains by a combination of radical polymerization and a condensation reaction. Quartz crystal microbalance with dissipation studies show that polyurethane can degrade in the presence of enzyme and the degradation rate decreases with the PTIPSA content. Our studies also demonstrate that polyurethane is able to hydrolyze in artificial seawater and the hydrolysis rate increases as the PTIPSA content increases. Moreover, hydrolysis leads to a hydrophilic surface that is favorable to reduction of the frictional drag under dynamic conditions. Marine field tests reveal that polyurethane has good antifouling ability because polyurethane with a biodegradable PCL main chain and hydrolyzable PTIPSA side chains can form a self-renewal surface. Polyurethane was also used to carry and release a relatively environmentally friendly antifoulant, and the combined system exhibits a much higher antifouling performance even in a static marine environment.

Radiation-resistance of polyurethane pipes for cooling liquid in BES III

International Nuclear Information System (INIS)

Li Xunfeng; Zheng Lifang; Ji Quan; Wu Ping; Wang Li

2009-01-01

Gamma ray radiation and neutron radiation are predominant in the working conditions of BES III, and the radiation-resistance aging of polyurethane pipes is very important in this condition, as the pipes of cooling liquid for beam pipe and SCQ (superconducting quadrupole) vacuum pipe in BESIII. Polyester polyurethane pipes and polyether polyurethane pipes were irradiated by gamma ray and neutron. The radiation doses were as much as ten years' doses in BES. Pressure test, FTIR and thermal analysis were used to study the radiation-resistance of these two kinds of polyurethane pipes. The results show that the radiation-resistance and thermal stability of polyester polyurethane pipes are prior to those of polyether polyurethane pipes, and the pressure resistance of polyester polyurethane pipes is almost maintained after the irradiation by gamma ray and neutron, but the polyether polyurethane pipes can be aged and ruptured after the irradiation by neutron. (authors)

Foam Microrheology

International Nuclear Information System (INIS)

KRAYNIK, ANDREW M.; LOEWENBERG, MICHAEL; REINELT, DOUGLAS A.

1999-01-01

The microrheology of liquid foams is discussed for two different regimes: static equilibrium where the capillary number Ca is zero, and the viscous regime where viscosity and surface tension are important and Ca is finite. The Surface Evolver is used to calculate the equilibrium structure of wet Kelvin foams and dry soap froths with random structure, i.e., topological disorder. The distributions of polyhedra and faces are compared with the experimental data of Matzke. Simple shearing flow of a random foam under quasistatic conditions is also described. Viscous phenomena are explored in the context of uniform expansion of 2D and 3D foams at low Reynolds number. Boundary integral methods are used to calculate the influence of Ca on the evolution of foam microstructure, which includes bubble shape and the distribution of liquid between films, Plateau borders, and (in 3D) the nodes where Plateau borders meet. The micromechanical point of view guides the development of structure-property-processing relationships for foams

dsmcFoam+: An OpenFOAM based direct simulation Monte Carlo solver

Science.gov (United States)

White, C.; Borg, M. K.; Scanlon, T. J.; Longshaw, S. M.; John, B.; Emerson, D. R.; Reese, J. M.

2018-03-01

dsmcFoam+ is a direct simulation Monte Carlo (DSMC) solver for rarefied gas dynamics, implemented within the OpenFOAM software framework, and parallelised with MPI. It is open-source and released under the GNU General Public License in a publicly available software repository that includes detailed documentation and tutorial DSMC gas flow cases. This release of the code includes many features not found in standard dsmcFoam, such as molecular vibrational and electronic energy modes, chemical reactions, and subsonic pressure boundary conditions. Since dsmcFoam+ is designed entirely within OpenFOAM's C++ object-oriented framework, it benefits from a number of key features: the code emphasises extensibility and flexibility so it is aimed first and foremost as a research tool for DSMC, allowing new models and test cases to be developed and tested rapidly. All DSMC cases are as straightforward as setting up any standard OpenFOAM case, as dsmcFoam+ relies upon the standard OpenFOAM dictionary based directory structure. This ensures that useful pre- and post-processing capabilities provided by OpenFOAM remain available even though the fully Lagrangian nature of a DSMC simulation is not typical of most OpenFOAM applications. We show that dsmcFoam+ compares well to other well-known DSMC codes and to analytical solutions in terms of benchmark results.

Analysis and model testing of a Super Tiger Type B waste transport system in accident environments

International Nuclear Information System (INIS)

May, R.A.; Yoshimura, H.R.; Romesberg, L.E.; Joseph, B.J.

1980-01-01

Sandia National Laboratories is investigating the response of a Type B packaging containing drums of contact-handled transuranic waste (CH-TRU) as a part of a program to evaluate the adequacy of experimental and analytical methods for assessing the safety of waste transport systems in accident environments. A US NRC certified Type B package known as the Super Tiger was selected for the study. This overpack consists of inner and outer steel shells separated by rigid polyurethane foam and can be used for either highway or rail transportation. Tests using scale models of the vehicular system are being conducted in conjunction with computer analyses

Toxicity of pyrolysis gases from some cellular polymers

Science.gov (United States)

Hilado, C. J.; Machado, A. M.

1978-01-01

Various samples of cellular polymers were evaluated for toxicity of pyrolysis gases, using the screening test method developed at the University of San Francisco. The cellular polymer samples included polyimide, polymethacrylimide, polybismaleimide, polyurethane, polyisocyanurate, polyethylene, polychloroprene, polyvinyl chloride, polystyrene, polysiloxane, and polyphosphazene. The cellular polymers exhibited varying levels of toxicity under these test conditions. Among the rigid cellular polymers, times to death were shortest with the imide type foams and longest with polyvinyl chloride and polystyrene. Among the flexible cellular polymers, times to death were shortest with polyimide and polyester, and longest with polychloroprene and polysiloxane. Increased char yield was not necessarily associated with reduced toxicity.

A prospective, randomized clinical trial to assess the cost-effectiveness of a modern foam dressing versus a traditional saline gauze dressing in the treatment of stage II pressure ulcers.

Science.gov (United States)

Payne, Wyatt G; Posnett, John; Alvarez, Oscar; Brown-Etris, Marie; Jameson, Gayle; Wolcott, Randall; Dharma, Hussein; Hartwell, Samantha; Ochs, Diane

2009-02-01

Modern dressings such as hydrocolloids, gels, and foams are typically more expensive than traditional dressings such as gauze. However, if modern dressings require fewer changes, the overall cost of treatment may be lower despite the higher initial purchase price. If healing rates are comparable or better, modern dressings also may be cost-effective. A 4-week, prospective, randomized clinical trial to assess differences in treatment costs and cost-effectiveness between a modern foam dressing and saline-soaked gauze was conducted among 36 patients (22 men, 14 women, mean age 72.8 years) with a Stage II pressure ulcer (mean duration 35 weeks) at five centers in the United States. Participants were randomized to treatment with a self-adhesive polyurethane foam (n = 20) or saline-soaked gauze dressing (n = 16). No difference in time to wound closure was observed (P = 0.817). Patients in the foam group had less frequent dressing changes (P cost over the study period was lower by $466 per patient (P = 0.055) and spending on dressings was lower by $92 per patient in the foam group (P = 0.025). Cost per ulcer healed was lower by $1,517 and cost per ulcer-free day was lower by $80 for patients in the foam group. On the evidence of this study, the foam dressing is a more cost-effective treatment than saline-soaked gauze for the treatment of Stage II pressure ulcers.

SYNTHESIS AND CHARACTERIZATION OF BIO-BASED POLYESTER POLYOL

Directory of Open Access Journals (Sweden)

MİTHAT ÇELEBİ

2016-11-01

Full Text Available Polyurethanes are versatile polymeric materials and are usually synthesised by isocyanate reactions with polyols. Due to the variety of isocyanates and polyols, particularly polyols, polyurethanes can be easily tailored for wide applications, such as rigid and flexible foams, coatings, adhesives, and elastomers. Considerable efforts have been recently devoted to developing bio-based substitutes for petroleum-based polyuretahanes due to increasing concerns over the depletion of petroleum resources, environment, and sustainability. Polyester polyols based on aliphatic and aromatic dicarboxylic acids are one of the most important materials in polymer technologies. Large volume of plants oils are used as renewable resources to produce various chemicals which are industrially important to make soaps, cosmetic products, surfactants, lubricants, diluents, plasticizers, inks, agrochemicals, composite materials, food industry. This study introduces synthesis and properties of bio-based polyols from different renewable feedstocks including vegetable oils and derivatives. A comparison of bio-based polyol properties with their petroleum-based analogues were investigated.

Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold.

Science.gov (United States)

Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

2014-02-01

The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials. © 2013.

Polyurethane-Coated Breast Implants Revisited: A 30-Year Follow-Up

Directory of Open Access Journals (Sweden)

Nikki Castel

2015-03-01

Full Text Available BackgroundPolyurethane coating of breast implants has been shown to reduce capsular contracture in short-term follow-up studies. This 30-year study is the longest examination of the use of polyurethane-coated implants and their correlation with capsular contracture.MethodsThis study evaluates the senior surgeon's (F.D.P. experience with the use of polyurethane-coated implants in aesthetic breast augmentation in 382 patients over 30 years. Follow-up evaluations were conducted for six months after surgery. After the six-month follow-up period, 76 patients returned for reoperation. The gross findings, histology, and associated capsular contracture were noted at the time of explantation.ResultsNo patient during the six-month follow-up period demonstrated capsular contracture. For those who underwent reoperation for capsular contracture, Baker II/III contractures were noted nine to 10 years after surgery and Baker IV contractures were noted 12 to 21 years after surgery. None of the explanted implants had macroscopic evidence of polyurethane, which was only found during the first five years after surgery. The microscopic presence of polyurethane was noted in all capsules up to 30 years after the original operation.ConclusionsAn inverse correlation was found between the amount of polyurethane coating on the implant and the occurrence of capsular contracture. Increasingly severe capsular contracture was associated with a decreased amount of polyurethane coating on the surface of the implants. No contracture occurred in patients whose implants showed incomplete biodegradation of polyurethane, as indicated by the visible presence of polyurethane coating. We recommend research to find a non-toxic, non-biodegradable synthetic material as an alternative to polyurethane.