Effect of plasticiser on properties of styrene-butadiene-styrene thermoplastic elastomers

International Nuclear Information System (INIS)

Norzalia, S.; Farid, A.S.; O'Brien, M.G.

1999-01-01

This study investigates the properties of plasticised styrene-butadiene-styrene thermoplastic elastomers for possible applications in pharmaceutical, medical and food industries. Unplasticised styrene-butadiene-styrene (USBS) materials: vector 8550-D and vector 4461-D, which are developmental materials introduced by Exxon, and blends of vector 8550-D with vector 4461-D were plasticised paraffinic type plasticisers plastol 172 and plastol 352. Shore A hardness, tensile stress at break, modulus at 100% strain, elongation at break and density values showed a decrease whereas flow properties such as melt flow index (MFI) increased considerably with increasing plasticiser concentration. The properties of the plasticised styrene-butadiene-styrene thermoplastic elastomers were compared to the USBS materials. (author)

Enhanced surface friction coefficient and hydrophobicity of TPE substrates using an APPJ system

Energy Technology Data Exchange (ETDEWEB)

Sainz-García, Elisa, E-mail: elisa.sainzg@unirioja.es; Alba-Elías, Fernando, E-mail: fernando.alba@unirioja.es; Múgica-Vidal, Rodolfo, E-mail: rodolfo.mugica@alum.unirioja.es; González-Marcos, Ana, E-mail: ana.gonzalez@unirioja.es

2015-02-15

Highlights: • Coatings on thermoplastic elastomers by atmospheric pressure plasma jet. • Study of influence of APTES and FLUSI percentage on the coating's properties. • The best sample (AF{sub 75}) used 75% of APTES and 25% of FLUSI as precursor mixture. • Sample AF{sub 75} reduced a 51.5% the FC and increased a 4.4% the WCA. - Abstract: An APPJ system was used to deposit a coating that combines a low friction coefficient with a high water contact angle (WCA) on a thermoplastic elastomer substrate (TPE) that is used in automotive profiling. The main drawback of this research is that groups that improve the hydrophobicity of the surface worsen its tribological properties. To overcome this, this study explored the use of various mixtures of differing proportions of two precursors. They were a siloxane, aminopropyltriethoxysilane (APTES) that was used to reduce the friction coefficient by its content of SiO{sub x} and a fluorinated compound, (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trimethoxysilane (FLUSI) that was used to improve the water-repellency characteristics, due to the presence of CF{sub 2} long chains. The coatings were characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS), dynamic Water Contact Angle (WCA), stability tests and tribological tests. It was found that an increase of the absorbance area under the SiOSi peak and inorganic groups is related to lower friction coefficients. On the other hand, the higher the CF{sub 2} percentage is, the higher the WCA is. The sample that was coated with 25% of FLUSI and 75% of APTES combined the improvements of both functional properties, the friction coefficient and the WCA. It has an average friction coefficient that is (0.530 ± 0.050) 51.5% lower and a WCA that is (θ{sub adv} = 119.8° ± 4.75) 4.4% higher than the uncoated TPE sample. A satisfactory

Application of thermo-plastic elestomers to electric wires

Energy Technology Data Exchange (ETDEWEB)

Yagyu, Hideki; Watanabe, Kiyoshi

1988-02-15

Thermoplastic elastomer (TPE) is used in only 1% of the total rubber and plastics in electric cable and wire fields. This report describes on the legal regulations, practical applications, and the future problems. Japanese regulation on the power cable is the use of specified materials only, whereas in Europe and USA the function of the material is given a priority. For the communication cable and for the material selection of electronic and household wires, the priority of selection is the function of the material. Merits of TPE in use are the specialty properties unknown in the conventional materials, non-necessity of crosslinking, and the high productivity. PE is mainly used for the communication cable, PE and PVC for sheath. Telefone cord is the biggest outlet of TPE presently. Other applications are found in connection cable between the OA equipments, shield wire, and insulation cables for robots, aeroplanes, and ocean development units, etc.. For more expansion of applications, balance between the flexibility and various properties, water resistance and price should be improved. (7 figs, 3 tabs, 3 refs)

Flammability and Thermophysical Characterization of Thermoplastic Elastomer Nanocomposites

Science.gov (United States)

2004-08-01

State University – M. Namani • Southern Clay Products – D. Hunter • Applied Sciences Inc. – J. Glasglow • Omega Point Laboratories – S . Romo Financial...Characterization of Thermoplastic Elastomer Nanocomposites 5a. CONTRACT NUMBER F04611-99-C-0025 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ... S ) AND ADDRESS(ES) ERC, Inc,AFRL/PRS,10 E. Saturn Blvd.,Edwards AFB,CA,93524 8. PERFORMING ORGANIZATION REPORT NUMBER E04-082 9. SPONSORING

Promotion of tribological and hydrophobic properties of a coating on TPE substrates by atmospheric plasma-polymerization

Science.gov (United States)

Sainz-García, Elisa; Alba-Elías, Fernando; Múgica-Vidal, Rodolfo; Pantoja-Ruiz, Mariola

2016-05-01

Thermoplastic elastomers (TPE) are used in the automotive sealing industry with the objective of producing anti-friction and hydrophobic components. At present, the anti-friction property is achieved by the electrostatic flocking, which sometimes produces an irregular coating. Therefore, this paper's objective is the promotion of adhesion of an anti-friction (based on the silane aminopropyltriethoxysilane-APTES-) and hydrophobic (based on the fluorinated precursor 1-perfluorohexene-PFH-) coating by the adhesion promoter, APTES. Different mixtures of APTES and PFH have been applied to a TPE substrate by an Atmospheric Pressure Plasma Jet (APPJ) system with Dielectric Barrier Discharge (DBD) in order to determine the optimal mixture of precursors. The main difficulty in this work lies in the hydrophilic character of APTES and the low adhesion of the fluorinated coatings. The sample coated with a mixture of 50% APTES and 50% PFH (A50P50) was found to be the best one to satisfy both properties at the same time, despite not having the highest dynamic water contact angle (WCA) or the lowest friction coefficient.

Synthesis and characterization of energetic thermoplastic elastomers for propellant formulations

Directory of Open Access Journals (Sweden)

Aparecida M. Kawamoto

2009-01-01

Full Text Available Synthesis and characterization of energetic ABA-type thermoplastic elastomers for propellant formulations has been carried out. Following the working plan elaborated, the synthesis and characterization of Poly 3- bromomethyl-3-methyl oxetane (PolyBrMMO, Poly 3- azidomethyl-3-methyl oxetane (PolyAMMO, Poly 3,3-bis-azidomethyl oxetane (PolyBAMO and Copolymer PolyBAMO/AMMO (by TDI end capping has been successfully performed. The thermoplastic elastomers (TPEs were synthesized using the chain elongation process PolyAMMO, GAP and PolyBAMO by diisocyanates. In this method 2.4-toluene diisocyanate (TDI is used to link block A (hard and mono- functional to B (soft and di-functional. For the hard A-block we used PolyBAMO and for the soft B-block we used PolyAMMO or GAP.This is a joint project set up, some years ago, between the Chemistry Division of the Institute of Aeronautics and Space (IAE - subordinated to the Brazilian Ministry of Defense - and the Fraunhofer Institut Chemische Technologie (ICT, in Germany. The products were characterized by different techniques as IR- and (1H,13CNMR spectroscopies, elemental and thermal analyses. New methodologies based on FT-IR analysis have been developed as an alternative for the determination of the molecular weight and CHNO content of the energetic polymers.

Coaxial Thermoplastic Elastomer-Wrapped Carbon Nanotube Fibers for Deformable and Wearable Strain Sensors

KAUST Repository

Zhou, Jian; Xu, Xuezhu; Xin, Yangyang; Lubineau, Gilles

2018-01-01

performances in these design requirements. Here, achieving highly stretchable and sensitive strain sensors by using a coaxial structure, prepared via coaxial wet spinning of thermoplastic elastomer-wrapped carbon nanotube fibers, is proposed. The sensors attain

Thermal Characterization of Modified Tacca Leontopetaloides Starch and Natural Rubber Based Thermoplastic Elastomer

International Nuclear Information System (INIS)

Ainatul Mardhiah Mohd Amin; Nur Shahidah Ab Aziz; Nurul Shuhada Mohd Makhtar; Miradatul Najwa Mohd Rodhi; Suhaila Mohd Sauid

2014-01-01

The purpose of this study is to identify the potential of Tacca leontopetaloides starch as bio-based thermoplastic elastomers, TPEs. Starch based polymer had been recognized to have highly potential in replace existing source of conventional elastomeric polymer. The modification process of blending starch with natural rubber, plasticizers, additives, and filler contribute to the enhancement and improvement for the properties of starch in order to produce biopolymers by approaching the properties of TPEs. Thermal properties of starch based thermoplastic was studied to evaluate the decomposition and degradation of the samples by using Thermogravimetric Analysis, TGA while the properties of endothermic reactions of the samples were thermally analyzed via Differential Scanning Calorimetry, DSC. From the analysis, it was found that the thermal properties of samples were revealed by recognizing GM-2 (green materials, GM) has high thermal resistance towards high temperature up to 480.06 degree Celsius with higher amount of residue which is 4.97 mg compared to other samples. This indicates GM-2 comprises of superior combination of ratio between natural rubbers and glycerol (plasticizer) in purpose of approaching the properties of Thermoplastic Elastomers, TPEs. (author)

Synthesis of thermoplastic poly(ester-olefin elastomers

Directory of Open Access Journals (Sweden)

Tanasijević Branka

2004-01-01

Full Text Available A series of thermoplastic poly(ester-olefin elastomers, based on poly(ethylene-stat-butylene, HO-PEB-OH, as the soft segment and poly (butylene terephthalate, PBT, as the hard segment, were synthesized by a catalyzed transesterification reaction in solution. The incorporation of soft hydrogenated poly(butadiene segments into the copolyester backbone was accomplished by the polycondensation of α, ω-dihydroxyl telechelic HO-PEB-OH, (PEB Mn = 3092 g/mol with 1,4-butanediol (BD and dimethyl terephthalate (DMT in the presence of a 50 wt-% high boiling solvent i.e., 1,2,4-trichlorobenzene. The molar ratio of the starting comonomers was selected to result in a constant hard to soft weight ratio of 60:40. The synthesis was optimized in terms of both the concentration of catalyst, tetra-n-butyl-titanate (Ti(OBu4, and stabilizer, N,N'-diphenyl-p-phenylenediamine (DPPD, as well as the reaction time. It was found that the optimal catalyst concentration (Ti(OBu4 for the synthesis of these thermoplastic elastomers was 1.0 mmol/mol ester and the optimal DPPD concentration was 1.0 wt-%. The extent of the reaction was followed by measuring the inherent viscosity of the reaction mixture. The effectiveness of the incorporation of the soft segments into the copolymer chains was proved by Soxhlet extraction with chloroform. The molecular structures, composition and the size of the synthesized poly(ester-butylenes were verified by 1H NMR spectroscopy, viscometry of dilute solutions and the complex dynamic melt viscosity. The thermal properties of poly(ester-olefins were investigated by differential scanning calorimetry (DSC. The degree of crystallinity was also determined by DSC. The thermal and thermo-oxidative stability were investigated by thermogravimetric analysis (TGA. The rheological properties of poly(ester-olefins were investigated by dynamic mechanical spectroscopy in the melt and solid state.

Sustainable Triblock Copolymers for Application as Thermoplastic Elastomers

Science.gov (United States)

Ding, Wenyue; Wang, Shu; Ganewatta, Mitra; Tang, Chuanbing; Robertson, Megan

Thermoplastic elastomers (TPEs), combining the processing advantages of thermoplastics with the flexibility and extensibility of elastomeric materials, have found versatile applications in industry, including electronics, clothing, adhesives, and automotive components. ABA triblock copolymers, in which A represents glassy endblocks and B the rubbery midblock, are commercially available as TPEs, such as poly(styrene-b-butadiene-b-styrene) (SBS) or poly(styrene-b-isoprene-b-styrene) (SIS). However, the commercial TPEs are derived from fossil fuels. The finite availability of fossil fuels and the environmental impact of the petroleum manufacturing have led to the increased interest in the development of alternative polymeric materials from sustainable sources. Rosin acids are promising replacement for the petroleum source due to their abundance in conifers, rigid molecular structures, and ease of functionalization. In this study, we explored the utilization of a rosin acid derivative, poly(dehydroabietic ethyl methacrylate) (PDAEMA), as a sustainable alternative for the glassy domain. The triblock copolymer poly(dehydroabietic ethyl methacrylate-b-n-butyl acylate-b-dehydroabietic ethyl methacrylate) (DnBD) was synthesized and characterized. DnBD exhibited tunable morphological and thermal properties. Tensile testing revealed elastomeric behavior.

Significant Enhancement of Mechanical and Thermal Properties of Thermoplastic Polyester Elastomer by Polymer Blending and Nanoinclusion

Directory of Open Access Journals (Sweden)

Manwar Hussain

2016-01-01

Full Text Available Thermoplastic elastomer composites and nanocomposites were fabricated via melt processing technique by blending thermoplastic elastomer (TPEE with poly(butylene terephthalate (PBT thermoplastic and also by adding small amount of organo modified nanoclay and/or polytetrafluoroethylene (PTFE. We study the effect of polymer blending on the mechanical and thermal properties of TPEE blends with and without nanoparticle additions. Significant improvement was observed by blending only TPEE and virgin PBT polymers. With a small amount (0.5 wt.% of nanoclay or PTFE particles added to the TPEE composite, there was further improvement in both the mechanical and thermal properties. To study mechanical properties, flexural strength (FS, flexural modulus (FM, tensile strength (TS, and tensile elongation (TE were all investigated. Thermogravimetric analysis (TGA and differential scanning calorimetry (DSC were used to analyze the thermal properties, including the heat distortion temperature (HDT, of the composites. Scanning electron microscopy (SEM was used to observe the polymer fracture surface morphology. The dispersion of the clay and PTFE nanoparticles was confirmed by transmission electron microscopy (TEM analysis. This material is proposed for use as a baffle plate in the automotive industry, where both high HDT and high modulus are essential.

Thermoplastic elastomers containing 2D nanofillers: montmorillonite, graphene nanoplatelets and oxidized graphene platelets

OpenAIRE

Paszkiewicz Sandra; Pawelec Iwona; Szymczyk Anna; Rosłaniec Zbigniew

2015-01-01

This paper presents a comparative study on which type of platelets nanofiller, organic or inorganic, will affect the properties of thermoplastic elastomer matrix in the stronger manner. Therefore, poly(trimethylene terephthalate-block-poly(tetramethylene oxide) copolymer (PTT-PTMO) based nanocomposites with 0.5 wt.% of clay (MMT), graphene nanoplatelets (GNP) and graphene oxide (GO) have been prepared by in situ polymerization. The structure of the nanocomposites was characterized by transmis...

Enhanced surface friction coefficient and hydrophobicity of TPE substrates using an APPJ system

Science.gov (United States)

Sainz-García, Elisa; Alba-Elías, Fernando; Múgica-Vidal, Rodolfo; González-Marcos, Ana

2015-02-01

An APPJ system was used to deposit a coating that combines a low friction coefficient with a high water contact angle (WCA) on a thermoplastic elastomer substrate (TPE) that is used in automotive profiling. The main drawback of this research is that groups that improve the hydrophobicity of the surface worsen its tribological properties. To overcome this, this study explored the use of various mixtures of differing proportions of two precursors. They were a siloxane, aminopropyltriethoxysilane (APTES) that was used to reduce the friction coefficient by its content of SiOx and a fluorinated compound, (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trimethoxysilane (FLUSI) that was used to improve the water-repellency characteristics, due to the presence of CF2 long chains. The coatings were characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS), dynamic Water Contact Angle (WCA), stability tests and tribological tests. It was found that an increase of the absorbance area under the SiOSi peak and inorganic groups is related to lower friction coefficients. On the other hand, the higher the CF2 percentage is, the higher the WCA is. The sample that was coated with 25% of FLUSI and 75% of APTES combined the improvements of both functional properties, the friction coefficient and the WCA. It has an average friction coefficient that is (0.530 ± 0.050) 51.5% lower and a WCA that is (θadv = 119.8° ± 4.75) 4.4% higher than the uncoated TPE sample. A satisfactory stability in humid ambient for twelve months showed a slight decrease of WCA (4.4%) for this sample. The results of this study permit one to realize the effectiveness of using fluorinated precursors to avoid a significant decrease in the WCA when applying a precursor to anti-friction improvement.

Microstructure And Mechanical Properties Of Lead Oxide- Thermoplastic Elas Tomer Composite

International Nuclear Information System (INIS)

Sudirman; Handayani, Ari; Darwinto, Tri; Teguh, Yulius S.P.P.; Sunarni, Anik; Marlijanti, Isni

2000-01-01

Research on microstructure and mechanical properties of lead oxide-thermoplastic elastomer composite with Pb 3 O 4 as lead oxide. Thermoplastic elastomer synthesized from natural rubber as the elastomer and methyl metacrilate as the thermoplastic and irradiated simultaneously with optimum gamma ray. Thermoplastic elastomer (NR-PMMA) grind in a laboplastomill and Pb 3 O 4 was added in varied amount of 10%. 30%. 40% and 50%wt.The results showed that mechanical properties (tensile strength and elongation break) decreased as the Pb 3 O 4 composition increased. Microstructure from SEM observation showed that Pb 3 O 4 distributed evenly and having function as filler in composite

Thermoplastic Polyurethane Elastomer Nanocomposites: Morphology, Thermophysical, and Flammability Properties

Directory of Open Access Journals (Sweden)

Wai K. Ho

2010-01-01

Full Text Available Novel materials based on nanotechnology creating nontraditional ablators are rapidly changing the technology base for thermal protection systems. Formulations with the addition of nanoclays and carbon nanofibers in a neat thermoplastic polyurethane elastomer (TPU were melt-compounded using twin-screw extrusion. The TPU nanocomposites (TPUNs are proposed to replace Kevlar-filled ethylene-propylene-diene-monomer rubber, the current state-of-the-art solid rocket motor internal insulation. Scanning electron microscopy analysis was conducted to study the char characteristics of the TPUNs at elevated temperatures. Specimens were examined to analyze the morphological microstructure during the pyrolysis reaction and in fully charred states. Thermophysical properties of density, specific heat capacity, thermal diffusivity, and thermal conductivity of the different TPUN compositions were determined. To identify dual usage of these novel materials, cone calorimetry was employed to study the flammability properties of these TPUNs.

Coaxial Thermoplastic Elastomer-Wrapped Carbon Nanotube Fibers for Deformable and Wearable Strain Sensors

KAUST Repository

Zhou, Jian

2018-01-22

Highly conductive and stretchable fibers are crucial components of wearable electronics systems. Excellent electrical conductivity, stretchability, and wearability are required from such fibers. Existing technologies still display limited performances in these design requirements. Here, achieving highly stretchable and sensitive strain sensors by using a coaxial structure, prepared via coaxial wet spinning of thermoplastic elastomer-wrapped carbon nanotube fibers, is proposed. The sensors attain high sensitivity (with a gauge factor of 425 at 100% strain), high stretchability, and high linearity. They are also reproducible and durable. Their use as safe sensing components on deformable cable, expandable surfaces, and wearable textiles is demonstrated.

Control of Mechanical Properties of Thermoplastic Polyurethane Elastomers by Restriction of Crystallization of Soft Segment

Directory of Open Access Journals (Sweden)

Sadaharu Nakamura

2010-12-01

Full Text Available Mechanical properties of thermoplastic polyurethane elastomers based on either polyether or polycarbonate (PC-glycols, 4,4’-dipheylmethane diisocyanate (1,1’-methylenebis(4-isocyanatobenzene, 1,4-butanediol, were controlled by restriction of crystallization of polymer glycols. For the polyether glycol based-polyurethane elastomers (PUEs, poly(oxytetramethylene glycol (PTMG, and PTMG incorporating dimethyl groups (PTG-X and methyl side groups (PTG-L were employed as a polymer glycol. For the PC-glycol, the randomly copolymerized PC-glycols with hexamethylene (C6 and tetramethylene (C4 units between carbonate groups with various composition ratios (C4/C6 = 0/100, 50/50, 70/30 and 90/10 were employed. The degree of microphase separation and mechanical properties of both the PUEs were investigated using differential scanning calorimetry, dynamic viscoelastic property measurements and tensile testing. Mechanical properties could be controlled by changing the molar ratio of two different monomer components.

Gun barrel erosion - Comparison of conventional and LOVA gun propellants

NARCIS (Netherlands)

Hordijk, A.C.; Leurs, O.

2006-01-01

The research department Energetic Materials within TNO Defence, Security and Safety is involved in the development and (safety and insensitive munitions) testing of conventional (nitro cellulose based) and thermoplastic elastomer (TPE) based gun propellants. Recently our testing capabilities have

Thermoplastic elastomer IPNs using radiation methods

International Nuclear Information System (INIS)

Burford, R.P.; Shirodkar, B.D.

2000-01-01

Full text: Styrene swollen, cross-linked TPEs can be thermally processed to give a new class of sequential interpenetrating polymer network (IPN). There are however certain limitations with this procedure, particularly in relation to the thermally initiated polymerization, including: the microscopic texture of the original TPE may be modified, the butadiene component of the TPE may thermally oxidize, safety concerns with monomer vapors at elevated temperatures exist; the concentration of monomer in the swollen TPE may change and be uneven. The method cannot be readily extended to the use of a volatile second monomer, such as butadiene or isoprene. Gamma radiation crosslinking allows uniform penetration and ambient temperatures. We used the multifunctional cross-linker, TMPTA, as this has been shown to work well under these conditions with styrene. Peroxide cross-linked Solprene 475 was swollen in inhibitor-free styrene containing 0, 10 and 33% by weight TMPTA and irradiated at 3 kGy/hr for total doses ranging typically from 50 to 1000 kGy. Hardnesses (Durometer Shore D) increased from 50 to plateau at about 65 units, and tensile strengths are ∼ 10-15 MPa. Initial data indicates breaking strains in the range 20 to 90%. A key observation is that the products were of uniform hardness and appearance, in contrast to many of the thermally prepared materials in the past, which also showed yellowing due to polybutadiene oxidation. Products were stained with osmium tetroxide, ultramicrotomed and observed by TEM. The morphologies of the new materials are more uniform than before, with less evidence of orientation. The previous structures were typically of swollen styrene rich rods in a butadiene matrix, whereas here the TEMs reveal a spongelike texture

Effects of composition and processing conditions on morphology and properties of thermoplastic elastomer blends of SEBS-PP-Oil and dynamically vulcanized EPDM-PP-Oil

NARCIS (Netherlands)

Sengupta, P.; Noordermeer, Jacobus W.M.

2004-01-01

This work presents a comparative study of the morphology and structure-related properties of thermoplastic elastomer blends based on SEBS-PP-oil and dynamically vulcanized EPDM-PP-oil prepared under identical conditions. Compositions of each blend type with three different SEBS-PP and EPDM-PP ratios

Thermoplastic elastomers containing 2D nanofillers: montmorillonite, graphene nanoplatelets and oxidized graphene platelets

Directory of Open Access Journals (Sweden)

Paszkiewicz Sandra

2015-12-01

Full Text Available This paper presents a comparative study on which type of platelets nanofiller, organic or inorganic, will affect the properties of thermoplastic elastomer matrix in the stronger manner. Therefore, poly(trimethylene terephthalate-block-poly(tetramethylene oxide copolymer (PTT-PTMO based nanocomposites with 0.5 wt.% of clay (MMT, graphene nanoplatelets (GNP and graphene oxide (GO have been prepared by in situ polymerization. The structure of the nanocomposites was characterized by transmission electron microscopy (TEM in order to present good dispersion without large aggregates. It was indicated that PTT-PTMO/GNP composite shows the highest crystallization temperature. Unlike the addition of GNP and GO, the introduction of MMT does not have great effect on the glass transition temperature of PTMO-rich soft phase. An addition of all three types of nanoplatelets in the nanocomposites caused the enhancement in tensile modulus and yield stress. Additionally, the cyclic tensile tests showed that prepared nanocomposites have values of permanent set slightly higher than neat PTT-PTMO.

Structure-Property Relationships in Tough, Superabsorbent Thermoplastic Elastomers for Hemorrhage Control

Science.gov (United States)

Beyer, Frederick; Bain, Erich; Long, Tyler; Mrozek, Randy; Savage, Alice; Martin, Halie; Dadmun, Mark; Lenhart, Joseph

Between 2001 and 2009, uncontrolled hemorrhaging from major trauma accounted for the deaths of roughly 80% of wounded soldiers with potentially survivable injuries. Modern hemostatic materials are limited in their ability to deliver therapeutic agents, causing tissue damage themselves, or being difficult to remove intact. The goal of this study is to create a mechanically robust polymer that takes up as much as 1000 wt% water in seconds while maintaining sufficient toughness to be removed intact from the wound intact. A thermoplastic elastomer scaffold in which physical crosslinks provide mechanical toughness might provide an appropriate combination of fast swelling and excellent toughness if the matrix material can be engineered to be strongly hydrophilic and swell rapidly. In this work, a commercial SBS triblock copolymer has been modified with poly(acrylic acid) side chains, resulting in materials that are superabsorbent but retain good mechanical properties when saturated. Although SAXS experiments failed to show any significant changes in morphology, even with 800 wt% water uptake, preliminary SANS experiments using selectively deuterated materials and swelling with D2O show significant changes in morphology. Our most recent findings will be presented.

A novel thermoplastic elastomer based on dynamically vulcanized polypropylene/acrylic rubber blends

Directory of Open Access Journals (Sweden)

2008-08-01

Full Text Available Thermoplastic elastomer based on polypropylene (PP and acrylic rubber (ACM was investigated, with special attention on the compatibilization and dynamic vulcanization. ACM component contains chlorine and carboxyl groups along the backbone, which act as center for the curing and reactive compatibilization. The last event was carried out by adding a combination of maleic anhydride-modified PP (PP-g-MA and triethylene tetramine (TETA, which act as interfacial agents between PP and ACM phases. The effectiveness of the compatibilization was suggested from mixing torque and viscosity, determined from rheological measurements. Outstanding mechanical performance, especially elongation at break, and better tensile set (lower values were obtained with the compatibilization. The dynamic vulcanization also resulted in good mechanical properties for compatibilized blends, but the performance was inferior to that observed for non vulcanized blends. The effect of the compatibilization and/or dynamic vulcanization on the dynamic mechanical, thermal, morphological and stress relaxation properties was investigated.

Data processing system for TPE-1 to TPE-1RM15

International Nuclear Information System (INIS)

Yahagi, Eiichi

1991-01-01

This paper reports the research and development of the data acquisition and processing system for TPE-1 to TPE-1RM15. The program to develop the system was initiated for the TPE-1 project in 1971. The TPE-1 machine was afterward reconstructed into TPE-1R, TPE-1RM and TPE-1RM15 in order. During this course, some modifications and improvements on the system had been made. The system had worked well for fifteen years from the end of 1973 fiscal year to the end of 1988 fiscal year. In 1989 the system was replaced by the present system, which will be described in a separate report. TPE-1 is a high-beta toroidal screw pinch machine for the magnetic confinement nuclear fusion research at the Electrotechnical Laboratory (ETL). TPE-1R, TPE-1RM and TEP-1RM15, are reversed field pinch machines. In the design of the system, the particular attention was paid to several problems inherent to high-beta plasma diagnostics, such as responsibility up to 10MHz, sensitivity at a very low signal level and protection against intense electromagnetic noises. The mean time to perform a floating point instruction was several hundred microseconds. We had made various contrivances and efforts to perform required work within the required time under the situation of the small memory area and the low throughput of the computer system. In this paper, general lines of the system design and development, and the hardware and software of the system including the filing system are described in detail. Some schemes to give high-quality data for analytical processing stage by means of pattern recognition of data signals, smoothing and other techniques, as well as a basic structurization of procedural software to save resources and labors, are also described. (J.P.N.)

Evaluation of the degree of dispersion of organoclay on nanocomposites with PP/EPDM; Avaliacao do grau de dispersao de argilas organofilicas em nanocompositos de PP/EPDM

Energy Technology Data Exchange (ETDEWEB)

Braga, F.C.F.; Oliveira, M.G., E-mail: fernanda.braga@int.gov.b [Instituto Nacional de Tecnologia (DPCM/INT), Rio de Janeiro, RJ (Brazil). Div. de Processamento e Caracterizacao de Materiais; Furtado, C.R.G. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

2010-07-01

Nanocomposites of thermoplastic elastomer (TPE) composed by PP/EPDM 1/1 blend and organoclay were obtained by the melt intercalation in an internal chamber mix. Initially, a masterbatch of maleinized polypropylene (PP-MA) and clay modified with alkyl ammonium salt in the ratio 3:1 was prepared, and then, added to TPE matrix to obtain loads of 2,5; 5 and 7 wt% of clay in the nanocomposite. The dispersion degree of clay in TPE matrix was evaluated by X-ray diffraction and parallel plate rheometry. The intercalation/exfoliate degree or the degree of dispersion varied with clay content, as observed by X-ray diffraction. This behavior was confirmed by the profile of the curves of elastic modulus versus frequency, which presented different slopes in the region of low frequency, due to the presence of clay and PP-MA. (author)

Evaluation of the degree of dispersion of organoclay on nanocomposites with PP/EPDM

International Nuclear Information System (INIS)

Braga, F.C.F.; Oliveira, M.G.

2010-01-01

Nanocomposites of thermoplastic elastomer (TPE) composed by PP/EPDM 1/1 blend and organoclay were obtained by the melt intercalation in an internal chamber mix. Initially, a masterbatch of maleinized polypropylene (PP-MA) and clay modified with alkyl ammonium salt in the ratio 3:1 was prepared, and then, added to TPE matrix to obtain loads of 2,5; 5 and 7 wt% of clay in the nanocomposite. The dispersion degree of clay in TPE matrix was evaluated by X-ray diffraction and parallel plate rheometry. The intercalation/exfoliate degree or the degree of dispersion varied with clay content, as observed by X-ray diffraction. This behavior was confirmed by the profile of the curves of elastic modulus versus frequency, which presented different slopes in the region of low frequency, due to the presence of clay and PP-MA. (author)

Tailoring the mechanical and biodegradable properties of binary blends of biomedical thermoplastic elastomer.

Science.gov (United States)

Ang, Hui Ying; Chan, Jingni; Toong, Daniel; Venkatraman, Subbu S; Chia, Sing Joo; Huang, Ying Ying

2018-03-01

Blending polymers with complementary properties capitalizes on the inherent advantages of both components, making it possible to tailor the behaviour of the resultant material. A polymer blend consisting of an elastomer and thermoplastic can help to improve the mechanical integrity of the system without compromising on its processibility. A series of blends of biodegradable Poly(L-lactide-co-ɛ-caprolactone) (PLC) and Poly-(l,l-lactide-co-glycolic acid) (PLLGA), and PLC with Poly-(d,l-lactide-co-glycolic acid) (PDLLGA) were evaluated as a potential material for a biodegradable vesicourethral connector device. Based on the Tg of the blends, PLC/PLLGA formed an immiscible mixture while PLC/PDLLGA resulted in a compatible blend. The results showed that with the blending of PLC, the failure mode of PLLGA and PDLLGA changed from brittle to ductile fracture, with an significant decreas in tensile modulus and strength. SEM images demonstrated the different blend morphologies of different compositions during degradation. Gel Permeation Chromatography (GPC) and mechanical characterization revealed the degradation behaviour of the blends in this order (fastest to slowest): PDLLGA and PLC/PDLLGA blends > PLLGA and PLC/PLLGA blends > PLC. The PLC/PLLGA (70:30) blend was recommended as a suitable for the vesicourethral connector device application, highlighting the tailoring of blends to achieve a desired mechanical performance. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assembly injection moulding joins metal and thermoplastics; Montagespritzgiessen verbindet Metall und Thermoplast

Energy Technology Data Exchange (ETDEWEB)

Drummer, Dietmar; Meister, Steve [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Kunststofftechnik; Reichart, Marc [HBW Gubesch Kunststoff Engineering GmbH, Wilhelmsdorf (Germany)

2010-03-08

Automotive safety restraint system components increasingly use flexible styrenic and olefinic TPEs. With continued evolution in automotive interior design and performance requirements, demands on material technology are concomitantly rising. A growing trend towards molded in color solutions with low gloss aesthetics require TPE materials with ery low gloss, improved scratch resistance, and low temperature ductility. Innovations utilizing Teknor Apex's compounding technology have enabled the development of low gloss styrenic elastomers for airbag door applications that provide an optimized combination of low temperature performance, surface aesthetics (low gloss and improved scratch resistance), and ease of processing. This paper highlights the salient features of these new compounds and the effect of injection molding condition on the gloss at the surface of the cover.

Poly(CL/DLLA-b-CL multiblock copolymers as biodegradable thermoplastic elastomers

Directory of Open Access Journals (Sweden)

2008-03-01

Full Text Available Lactic acid and ∑-caprolactone based polymers and their derivates are widely used in biomedical applications. Different properties are introduced by modifying the composition. In this study, poly(ε-caprolactone/D,L-lactide-b-poly(ε-caprolactone multiblock copolymers were synthesized as poly(ester-urethanes (PEUs by polymerizing in two steps involving ring-opening polymerization of precursors and by diisocyanate linking of precursors to produce thermoplastic elastomers (TPEs. The precursors and products were characterized by SEC, 1H-NMR and DSC, and dynamic mechanical study (by dynamic mechanical analysis, DMA as well as morphological characterization (by transmission electron microscopy, TEM of the product TPEs was carried out. Tensile and creep recovery properties of them were also studied. According to the characterizations, all the polymerizations were successful, and the prepared TPEs showed clear elastic behavior. In the DMA scans, rubbery plateau in the storage modulus curves between Tg and terminal flow region was clearly detectable indicating elasticity. The TEM images demonstrated phase separation of amorphous and crystalline blocks when the degree of crystallinity of the hard blocks was high enough. The elongations of TPEs varied between 800–1800%, while the modulus was 7–66 MPa. Two different types of recovery tests indicated the creep properties of TPEs to be highly dependent on the degree of crystallinity.

In situ development of self-reinforced cellulose nanocrystals based thermoplastic elastomers by atom transfer radical polymerization.

Science.gov (United States)

Yu, Juan; Wang, Chunpeng; Wang, Jifu; Chu, Fuxiang

2016-05-05

Recently, the utilization of cellulose nanocrystals (CNCs) as a reinforcing material has received a great attention due to its high elastic modulus. In this article, a novel strategy for the synthesis of self-reinforced CNCs based thermoplastic elastomers (CTPEs) is presented. CNCs were first surface functionalized with an initiator for surface-initiated atom transfer radical polymerization (SI-ATRP). Subsequently, SI-ATRP of methyl methacrylate (MMA) and butyl acrylate (BA) was carried out in the presence of sacrificial initiator to form CTPEs in situ. The CTPEs together with the simple blends of CNCs and linear poly(MMA-co-BA) copolymer (P(MMA-co-BA)) were characterized for comparative study. The results indicated that P(MMA-co-BA) was successfully grafted onto the surface of CNCs and the compatibility between CNCs and the polymer matrix in CTPEs was greatly enhanced. Specially, the CTPEs containing 2.15wt% CNCs increased Tg by 19.2°C and tensile strength by 100% as compared to the linear P(MMA-co-BA). Copyright © 2016 Elsevier Ltd. All rights reserved.

Shape Memory Composites Based on Electrospun Poly(vinyl alcohol) Fibers and a Thermoplastic Polyether Block Amide Elastomer.

Science.gov (United States)

Shirole, Anuja; Sapkota, Janak; Foster, E Johan; Weder, Christoph

2016-03-01

The present study aimed at developing new thermally responsive shape-memory composites, that were fabricated by compacting mats of electrospun poly(vinyl alcohol) (PVA) fibers and sheets of a thermoplastic polyether block amide elastomer (PEBA). This design was based on the expectation that the combination of the rubber elasticity of the PEBA matrix and the mechanical switching exploitable through the reversible glass transition temperature (Tg) of the PVA filler could be combined to create materials that display shape memory characteristics as an emergent effect. Dynamic mechanical analyses (DMA) show that, upon introduction of 10-20% w/w PVA fibers, the room-temperature storage modulus (E') increased by a factor of 4-5 in comparison to the neat PEBA, and they reveal a stepwise reduction of E' around the Tg of PVA (85 °C). This transition could indeed be utilized to fix a temporary shape and recover the permanent shape. At low strain, the fixity was 66 ± 14% and the recovery was 98 ± 2%. Overall, the data validate a simple and practical strategy for the fabrication of shape memory composites that involves a melt compaction process and employs two commercially available polymers.

Sustainable thermoplastic elastomers derived from cellulose, fatty acid and furfural via ATRP and click chemistry.

Science.gov (United States)

Yu, Juan; Lu, Chuanwei; Wang, Chunpeng; Wang, Jifu; Fan, Yimin; Chu, Fuxiang

2017-11-15

Cellulose-based thermoplastic elastomers (TPEs) have attracted considerable attention because of their rigid backbone, good mechanical properties, renewable nature and abundance. In the present study, sustainable TPEs based on ethyl cellulose (EC), fatty acid and furfural were generated by the combination of ATRP and "click chemistry". To fabricate sustainable TPEs with higher toughness, a range of polymers, including mono random-copolymer poly(tetrahydrofurfuryl methacrylate-co-lauryl methacrylate) (P(THFMA-co-LMA), dual polymer side chains PTHFMA and PLMA, and mono-block copolymer PTHFMA-b-PLMA, were designed as side chains to fabricate EC brush copolymers with random, dual or block side chain architectures using the "grafting from" and "grafting onto" methods. The multi-armed structures, chemical compositions and phase separation of these EC brush copolymers were confirmed by FT-IR, 1 H NMR, GPC, DSC, TEM and SEM. Overall, three types of EC brush copolymers all exhibited the desired mechanical properties of TPEs. In addition, the EC brush copolymers with dual/block side chain architectures showed higher tensile strength than that of the random polymers with similar compositions. Copyright © 2017. Published by Elsevier Ltd.

Radiation cross-linked polymers: Recent developments and new applications

International Nuclear Information System (INIS)

Rouif, Sophie

2005-01-01

The purpose of the present paper is to review the innovative and recent applications of radiation cross-linking of polymers that reinforces their dimensional stability in chemically aggressive and high temperature conditions. Radiation cross-linking can be applied to a great number of plastics: thermoplastics, elastomers and thermoplastic elastomers (TPE). Some of them can cross-link on their own, some others need to be formulated with a cross-linking agent (promoter) or to be modified during their polymerization. Some results of chemical and thermomechanical characterizations of radiation cross-linked plastics based on engineering polymers will be described, and their advantages will be emphasized in relation with their applications in various sectors: pipes and cables, packaging, automotive, electrical engineering and electronics, including connectors, surface mounted devices, integrated circuits, 3D-MID technology, etc. The paper will conclude with a short review of the industrial irradiation facilities (EB facilities and gamma plants) adapted to the treatment of such various products

Uniaxial Extensional Behavior of A--B--A Thermoplastic Elastomers: Structure-Properties Relationship and Modeling

Science.gov (United States)

Martinetti, Luca

At service temperatures, A--B--A thermoplastic elastomers (TPEs) behave similarly to filled (and often entangled) B-rich rubbers since B block ends are anchored on rigid A domains. Therefore, their viscoelastic behavior is largely dictated by chain mobility of the B block rather than by microstructural order. Relating the small- and large-strain response of undiluted A--B--A triblocks to molecular parameters is a prerequisite for designing associated TPE-based systems that can meet the desired linear and nonlinear rheological criteria. This dissertation was aimed at connecting the chemical and topological structure of A--B--A TPEs with their viscoelastic properties, both in the linear and in the nonlinear regime. Since extensional deformations are relevant for the processing and often the end-use applications of thermoplastic elastomers, the behavior was investigated predominantly in uniaxial extension. The unperturbed size of polymer coils is one of the most fundamental properties in polymer physics, affecting both the thermodynamics of macromolecules and their viscoelastic properties. Literature results on poly(D,L-lactide) (PLA) unperturbed chain dimensions, plateau modulus, and critical molar mass for entanglement effect in viscosity were reviewed and discussed in the framework of the coil packing model. Self-consistency between experimental estimates of melt chain dimensions and viscoelastic properties was discussed, and the scaling behaviors predicted by the coil packing model were identified. Contrary to the widespread belief that amorphous polylactide must be intrinsically stiff, the coil packing model and accurate experimental measurements undoubtedly support the flexible nature of PLA. The apparent brittleness of PLA in mechanical testing was attributed to a potentially severe physical aging occurring at room temperature and to the limited extensibility of the PLA tube statistical segment. The linear viscoelastic response of A--B--A TPEs was first

Preparation and Properties of Novel Thermoplastic Vulcanizate Based on Bio-Based Polyester/Polylactic Acid, and Its Application in 3D Printing

Directory of Open Access Journals (Sweden)

Yu Gao

2017-12-01

Full Text Available Thermoplastic vulcanizate (TPV combines the high elasticity of elastomers and excellent processability of thermoplastics. Novel bio-based TPV based on poly (lactide (PLA and poly (1,4-butanediol/2,3-butanediol/succinate/itaconic acid (PBBSI were prepared in this research. PBBSI copolyesters were synthesized by melting polycondensation, and the molecular weights, chemical structures and compositions of the copolyesters were characterized by GPC, NMR and FTIR. Bio-based 2,3-butanediol was successfully incorporated to depress the crystallization behavior of the PBBSI copolyester. With an increase of 2,3-butanediol content, the PBBSI copolyester transformed from a rigid plastic to a soft elastomer. Furthermore, the obtained TPV has good elasticity and rheological properties, which means it can be applied as a 3D-printing material.

Radiation cross-linked plastics: a versatile material solution for packaging, automotive, Electrotechnic and Electronics

International Nuclear Information System (INIS)

Rouif, Sophie

2004-01-01

Used since the beginning of the 1970s for the production of halogen-free and heat-resistant cables and wires, for conditioning polyethylene hot-water pipes or for the manufacture of heat shrinkable tubes and of tyres, radiation cross-linking is developing fastly today on the scale of plastic-moulded parts, and not only by the mean of EB, but also under gamma rays. Indeed, it improves considerably the performances of a great number of plastics among thermoplastics, elastomers and thermoplastic elastomers (TPE). Radiation cross-linking reinforces the dimensional stability of polymers in chemically aggressive and high-temperature conditions. Radiation cross-linked-based engineering plastics offers OEM and end users in many branches of industry both technical and economical advantages in comparison with high-performances plastics. They constitute a technical and economical compromise between engineering plastics that failed and high-performances plastic, often over-tailored and expensive. This modern industrial technology gives way to new applications and perspectives in various sectors (packaging, automotive, electrotechnic and electronics, including connectors, surface-mounted devices, integrated circuits, 3D-MID, etc.) that are described in the paper

Dynamic Mechanical Analysis and Three-Body Abrasive Wear Behaviour of Thermoplastic Copolyester Elastomer Composites

Directory of Open Access Journals (Sweden)

Hemanth Rajashekaraiah

2014-01-01

Full Text Available Various amounts of short fibers (glass and carbon and particulate fillers like polytetrafluoroethylene (PTFE, silicon carbide (SiC, and alumina (Al2O3 were systematically introduced into the thermoplastic copolyester elastomer (TCE matrix for reinforcement purpose. The mechanical properties such as storage modulus, loss modulus, and Tan δ by dynamic mechanical analysis (DMA and three-body abrasive wear performance on a dry sand rubber wheel abrasion tester have been investigated. For abrasive wear study, the experiments were planned according to L27 orthogonal array by considering three factors and three levels. The complex moduli for TCE hybrid composites were pushed to a higher level relative to the TCE filled PTFE composite. At lower temperatures (in the glassy region, the storage modulus increases with increase in wt.% of reinforcement (fiber + fillers and the value is maximum for the composite with 40 wt.% reinforcement. The loss modulus and damping peaks were also found to be higher by the incorporation of SiC and Al2O3 microfillers. The routine abrasive wear test results indicated that TCE filled PTFE composite exhibited better abrasion resistance. Improvements in the abrasion resistance, however, have not been achieved by short-fiber and particlaute filler reinforcements. From the Taguchi’s experimental findings, optimal combination of control factors were obtained for minimum wear volume and also predictive correlations were proposed. Further, the worn surface morphology of the samples was discussed.

Sustainable Elastomers from Renewable Biomass.

Science.gov (United States)

Wang, Zhongkai; Yuan, Liang; Tang, Chuanbing

2017-07-18

Sustainable elastomers have undergone explosive growth in recent years, partly due to the resurgence of biobased materials prepared from renewable natural resources. However, mounting challenges still prevail: How can the chemical compositions and macromolecular architectures of sustainable polymers be controlled and broadened? How can their processability and recyclability be enabled? How can they compete with petroleum-based counterparts in both cost and performance? Molecular-biomass-derived polymers, such as polymyrcene, polymenthide, and poly(ε-decalactone), have been employed for constructing thermoplastic elastomers (TPEs). Plant oils are widely used for fabricating thermoset elastomers. We use abundant biomass, such as plant oils, cellulose, rosin acids, and lignin, to develop elastomers covering a wide range of structure-property relationships in the hope of delivering better performance. In this Account, recent progress in preparing monomers and TPEs from biomass is first reviewed. ABA triblock copolymer TPEs were obtained with a soft middle block containing a soybean-oil-based monomer and hard outer blocks containing styrene. In addition, a combination of biobased monomers from rosin acids and soybean oil was formulated to prepare triblock copolymer TPEs. Together with the above-mentioned approaches based on block copolymers, multigraft copolymers with a soft backbone and rigid side chains are recognized as the first-generation and second-generation TPEs, respectively. It has been recently demonstrated that multigraft copolymers with a rigid backbone and elastic side chains can also be used as a novel architecture of TPEs. Natural polymers, such as cellulose and lignin, are utilized as a stiff, macromolecular backbone. Cellulose/lignin graft copolymers with side chains containing a copolymer of methyl methacrylate and butyl acrylate exhibited excellent elastic properties. Cellulose graft copolymers with biomass-derived polymers as side chains were

Microstructure and magnetorheological properties of the thermoplastic magnetorheological elastomer composites containing modified carbonyl iron particles and poly(styrene-b-ethylene-ethylenepropylene-b-styrene) matrix

International Nuclear Information System (INIS)

Qiao, Xiuying; Lu, Xiushou; Li, Wei; Sun, Kang; Li, Weihua; Chen, Jun; Gong, Xinglong; Yang, Tao; Chen, Xiaodong

2012-01-01

Novel isotropic and anisotropic thermoplastic magnetorheological elastomers (MRE) were prepared by melt blending titanated coupling agent modified carbonyl iron (CI) particles with poly(styrene-b-ethylene-ethylene–propylene-b-styrene) (SEEPS) matrix in the absence and presence of a magnetic field, and the microstructure and magnetorheological properties of these SEEPS-based MRE were investigated in detail. The particle surface modification improves the dispersion of the particles in the matrix and remarkably softens the CI/SEEPS composites, thus significantly enhancing the MR effect and improving the processability of these SEEPS-based MRE. A microstructural model was proposed to describe the interfacial compatibility mechanism that occurred in the CI/SEEPS composites after titanate coupling agent modification, and validity of this model was also demonstrated through adsorption tests of unmodified and surface-modified CI particles. (paper)

The Future of Swelling Elastomers: An Elastomer Manufacturer's View of Swelling Elastomer Developments and Market Trends

Directory of Open Access Journals (Sweden)

R Seyger

2013-06-01

Full Text Available Swelling elastomers have gained acceptance as very effective products for creating sealing in various industries, including those creating energy from fossil fuels and geothermal resources. This paper outlines the research and development work being conducted not only in the application of these elastomers but also in the development work required to create new generations of elastomers. It touches on fundamental research into the mechanics of swelling with the intent to create a better and more predictable sealing as well as more advanced elastomers. It lifts the veil on the direction of work being done on new elastomers being developed in order to enable a better control of swelling. By doing so, the research is opening up field of applications for new equipment designs and mechanical possibilities in the future. Additionally, it addresses the need for a better and more in-depth dialogue between both chemical and mechanical engineers, and the elastomer companies and their customers on the potential that both swelling and non-swelling elastomers can offer to the industry as a whole.

Biobased composites from thermoplastic polyurethane elastomer and cross-linked acrylated-epoxidized soybean oil

Science.gov (United States)

Soybean oil is an important sustainable material. Crosslinked acrylated epoxidized soybean oil (AESO) is brittle without flexibility and the incorporation of thermoplastic polyurethane improves its toughness for industrial applications. The hydrophilic functional groups from both oil and polyurethan...

Chimeric Plastics : a new class of thermoplastic

Science.gov (United States)

Sonnenschein, Mark

A new class of thermoplastics (dubbed ``Chimerics'') is described that exhibits a high temperature glass transition followed by high performance elastomer properties, prior to melting. These transparent materials are comprised of co-continuous phase-separated block copolymers. One block is an amorphous glass with a high glass transition temperature, and the second is a higher temperature phase transition block creating virtual thermoreversible crosslinks. The material properties are highly influenced by phase separation on the order of 10-30 nanometers. At lower temperatures the polymer reflects the sum of the block copolymer properties. As the amorphous phase glass transition is exceeded, the virtual crosslinks of the higher temperature second phase dominate the plastic properties, resulting in rubber-like elasticity.

Chemical Modification and Structure-property Relationships of Acrylic and Ionomeric Thermoplastic Elastomer Gels

Science.gov (United States)

Vargantwar, Pruthesh Hariharrao

Block copolymers (BCs) have remained at the forefront of materials research due to their versatility in applications ranging from hot-melt/pressure-sensitive adhesives and impact modifiers to compatibilizing agents and vibration-dampening/nanotemplating media. Of particular interest are macromolecules composed of two or more chemically dissimilar blocks covalently linked together to form triblock or pentablock copolymers. If the blocks are sufficiently incompatible and the copolymer behaves as a thermoplastic elastomer, the molecules can spontaneously self-assemble to form nanostructured materials that exhibit shape memory due to the formation of a supramolecular network. The BCs of these types are termed as conventional. When BCs contain blocks having ionic moieties such as sulfonic acid groups, they are termed as block ionomers. Designing new systems based on either conventional or ionic BCs, characterizing their structure-property relationships and later using them as electroacive polymers form the essential objectives of this work. Electroactive polymers (EAPs) exhibit electromechanical actuation when stimulated by an external electric field. In the first part of this work, it is shown that BCs resolve some of the outstanding problems presently encountered in the design of two different classes of EAP actuators: dielectric elastomers (DEs) and ionic polymer metal composites (IPMCs). All-acrylic triblock copolymer gels used as DEs actuate with high efficacy without any requirement of mechanical prestrain and, thus, eliminate the need for bulky and heavy hardware essential with prestrained dielectric actuators, as well as material problems associated with stress relaxation. The dependence of actuation behavior on gel morphology as evaluated from mechanical and microstructure studies is observed. In the case of IPMCs, ionic BCs employed in this study greatly facilitate processing compared to other contenders such as NafionRTM, which is commonly used in this class

Bimodal condensation silicone elastomers as dielectric elastomers

DEFF Research Database (Denmark)

Yu, Liyun; Madsen, Frederikke Bahrt; Skov, Anne Ladegaard

Lately, dielectric elastomers (DEs) which consist of an elastomer sandwiched between electrodes on both sides, have gained interest as materials for actuators, generators, and sensors. An ideal elastomer for DE uses is characterized by high extensibility, flexibility and good mechanical fatigue...... elastomers were prepared by mixing different mass ratios (9:1, 8:2, 7:3, 6:4, 5:5, 4:6) between long polydimethylsiloxane (PDMS) chains and short PDMS chains. The resulting elastomers were investigated with respect to their rheology, dielectric properties, tensile strength, electrical breakdown, as well.......Moreover, a series of elastomers with the same mass ratio (7:3) between long and short PDMS chains were made at different humidity (90%, 70%, 50%, 30%, 10%) at 23oC. The dielectric and mechincal properties of the resulting elastomers were shown to depend strongly on the atmospheric humidity level.In addition...

The objects and basic design of TPE-2

International Nuclear Information System (INIS)

Kiyama, Satoru; Ashida, Hisao; Hayase, Kiyoshi

1986-01-01

The objects and design of TPE-2 are described TPE-2 is a high beta toroidal screw pinch experiment. The magnetic field configuration of the screw pinch is the tokamaklike one (safty factor q > approx 1). The high beta plasma is obtained by the fast compression heating in TPE-2. The major objects of TPE-2 are to obtain a stable high beta plasma (> 10 %) in the configuration and to examine the behavior of the plasma in respect to given plasma parameters (T e ∼ T i > approx 300 eV, τ E > approx 0.4 ms, n e > approx 10 21 m -3 ). To atlain these objects, the optimum conditions of the machine parameters, such as aspect ratio, scale, rise time of the magnetic fields and others are analyzed for the beta, energy confinement, temperature and others. The analysis indicates that the aspect ratio and q must be small and the high veltage power supply is necessary. The designs of the coil and power supply system are briefly described. Several technical developments which are necessary for the construction of the apparatus are alss given, the diagnostic and data processing systems is included. The brief history of TPE-2 is described and the plasma parameters are compared with the designed values. (author)

Design and manufacturing of vacuum vessel of TPE-RX

Energy Technology Data Exchange (ETDEWEB)

Sago, H.; Kaguchi, H.; Orita, J.; Ishigami, Y. [Mitsubishi Heavy Industries Ltd., Kobe (Japan); Urata, K. [Mitsubishi Heavy Industries Ltd. (Japan). Nuclear Energy Systems Engineering Center; Hasegawa, M. [Mitsubishi Electric Co. (Japan). Nuclear Fusion Development; Yagi, Y.; Hirano, Y.; Shimada, T.; Sekine, S.; Sakakita, H. [Electrotechnical Lab. (Japan)

1998-07-01

Construction of a new, large reversed field pinch (RFP) machine called TPE-RX was complete at the end of 1997 as a successor of the previous TPE-1RM20 machine at the Electrotechnical Laboratory (ETL). RFP configuration has been successfully obtained in March 1998. This paper introduces structural design and manufacturing of the vacuum vessel of TPE-RX. The support positions were decided by structural analyses. The structural integrity of the vacuum vessel was evaluated by inelastic analyses. (author)

Design and manufacturing of vacuum vessel of TPE-RX

International Nuclear Information System (INIS)

Sago, H.; Kaguchi, H.; Orita, J.; Ishigami, Y.; Urata, K.

1998-01-01

Construction of a new, large reversed field pinch (RFP) machine called TPE-RX was complete at the end of 1997 as a successor of the previous TPE-1RM20 machine at the Electrotechnical Laboratory (ETL). RFP configuration has been successfully obtained in March 1998. This paper introduces structural design and manufacturing of the vacuum vessel of TPE-RX. The support positions were decided by structural analyses. The structural integrity of the vacuum vessel was evaluated by inelastic analyses. (author)

Thermoplastic vulcanizate nanocomposites based on polypropylene/ethylene propylene diene terpolymer (PP/EPDM) prepared by reactive extrusion

Science.gov (United States)

Mirzadeh, Amin

For this work, different grades of polypropylene-g-maleic anhydride polymers were chosen to elucidate the effect of compatibilizer on the nanoclay dispersion level in thermoplastic phase. X-ray diffraction (XRD) patterns along with transmission electron microscopy (TEM) and scanning electron microscope (SEM) micrographs confirmed that prepared PP nanocomposites ranged from intercalated structure to a coexistence of intercalated tactoids and exfoliated layers namely “partially exfoliated” nanocomposite. Among various factors affecting the compatibilizer performance, it is shown that only the relaxation behaviour of compatibilizer correlates directly with the nanocomposites characterization results; higher relaxation times of the compatibilizer are associated with better dispersion of nanoclay. To study the co-continuity development of the nonreactive blends, EPDM and the mentioned PP nanocomposites at various compositions were melt blended using an internal mixer. Based on continuity measurements of TPEs and TPE nanocomposites for both thermoplastic and rubber phase, it is shown that the presence of nanoclay decreases the co-continuity composition range and alters its symmetrical feature. However, this effect is more pronounced in the intercalated nanocomposites than in partially exfoliated nanocomposites. It seems that better nanoclay dispersion limits the reduction of the thermoplastic phase continuity in a manner that the continuity index of the thermoplastic phase for partially exfoliated TPE nanocomposite prepared at high EPDM content (i.e. at 70 wt%) is greater than that of corresponding TPE without nanoclay. According to these results, it is possible to shift to higher EPDM content using partially exfoliated system before formation of matrix-dispersed particle structure which limits thermoplastic vulcanizate production. This should be mentioned that gamma irradiation was carried out in order to fix the EPDM morphology to estimate the continuity of PP

Prolonged Tp-e Interval in Down Syndrome Patients with Congenitally Normal Hearts.

Science.gov (United States)

Kucuk, Mehmet; Karadeniz, Cem; Ozdemir, Rahmi; Meşe, Timur

2018-03-25

Heterogeneity of ventricular repolarization has been assessed by using the QT dispersion in Down syndrome (DS) patients with congenitally normal hearts. However, novel repolarization indexes, the Tp-e interval and Tp-e/QT ratio, have not previously been evaluated in these patients. The aim of this study was to evaluate the Tp-e interval and Tp-e/QT ratio in DS patients without congenital heart defects. Twelve-lead surface electrocardiograms of 160 DS patients and 110 age- and sex-matched healthy controls were used to evaluate and compare the Tp-e interval, Tp-e dispersion, and Tp-e/QT ratio. Heart rate, Tp-e interval, Tp-e dispersion, Tp-e/QT and Tp-e/QTc ratios were significantly higher in DS group than in the controls. Myocardial repolarization indexes in DS patients with congenitally normal hearts were found to be prolonged compared to those in normal controls. Further evaluation is warranted to reveal a relationship between prolonged repolarization indexes and arrhythmic events in these patients. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Development of a plasma driven permeation experiment for TPE

Energy Technology Data Exchange (ETDEWEB)

Buchenauer, Dean, E-mail: dabuche@sandia.gov [Sandia National Laboratories, Livermore, CA (United States); Kolasinski, Robert [Sandia National Laboratories, Livermore, CA (United States); Shimada, Masa [Idaho National Laboratory, Idaho Falls, ID (United States); Donovan, David [Sandia National Laboratories, Livermore, CA (United States); Youchison, Dennis [Sandia National Laboratories, Albuquerque, NM (United States); Merrill, Brad [Idaho National Laboratory, Idaho Falls, ID (United States)

2014-10-15

Highlights: • We have designed and fabricated a novel tritium permeation membrane holder for use in the Tritium Plasma Experiment (TPE). • The membrane temperature is controlled by varying the cooling flow rate and proximity of a spiral cooling channel. • Sealing tests have demonstrated adequate helium leak rates up to temperatures of 1000 °C. • Flow modeling indicates a minimal helium pressure drop across the membrane holder (<700 Pa). • Thermal modeling shows good heat removal and minimal membrane temperature variation (±2%) even up to peak TPE ion fluxes. - Abstract: Experiments on retention of hydrogen isotopes (including tritium) at temperatures less than 800 °C have been carried out in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory [1,2]. To provide a direct measurement of plasma driven permeation in plasma facing materials at temperatures reaching 1000 °C, a new TPE membrane holder has been built to hold test specimens (≤1 mm in thickness) at high temperature while measuring tritium permeating through the membrane from the plasma facing side. This measurement is accomplished by employing a carrier gas that transports the permeating tritium from the backside of the membrane to ion chambers giving a direct measurement of the plasma driven tritium permeation rate. Isolation of the membrane cooling and sweep gases from TPE's vacuum chamber has been demonstrated by sealing tests performed up to 1000 °C of a membrane holder design that provides easy change out of membrane specimens between tests. Simulations of the helium carrier gas which transports tritium to the ion chamber indicate a very small pressure drop (∼700 Pa) with good flow uniformity (at 1000 sccm). Thermal transport simulations indicate that temperatures up to 1000 °C are expected at the highest TPE fluxes.

Development of a plasma driven permeation experiment for TPE

International Nuclear Information System (INIS)

Buchenauer, Dean; Kolasinski, Robert; Shimada, Masa; Donovan, David; Youchison, Dennis; Merrill, Brad

2014-01-01

Highlights: • We have designed and fabricated a novel tritium permeation membrane holder for use in the Tritium Plasma Experiment (TPE). • The membrane temperature is controlled by varying the cooling flow rate and proximity of a spiral cooling channel. • Sealing tests have demonstrated adequate helium leak rates up to temperatures of 1000 °C. • Flow modeling indicates a minimal helium pressure drop across the membrane holder (<700 Pa). • Thermal modeling shows good heat removal and minimal membrane temperature variation (±2%) even up to peak TPE ion fluxes. - Abstract: Experiments on retention of hydrogen isotopes (including tritium) at temperatures less than 800 °C have been carried out in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory [1,2]. To provide a direct measurement of plasma driven permeation in plasma facing materials at temperatures reaching 1000 °C, a new TPE membrane holder has been built to hold test specimens (≤1 mm in thickness) at high temperature while measuring tritium permeating through the membrane from the plasma facing side. This measurement is accomplished by employing a carrier gas that transports the permeating tritium from the backside of the membrane to ion chambers giving a direct measurement of the plasma driven tritium permeation rate. Isolation of the membrane cooling and sweep gases from TPE's vacuum chamber has been demonstrated by sealing tests performed up to 1000 °C of a membrane holder design that provides easy change out of membrane specimens between tests. Simulations of the helium carrier gas which transports tritium to the ion chamber indicate a very small pressure drop (∼700 Pa) with good flow uniformity (at 1000 sccm). Thermal transport simulations indicate that temperatures up to 1000 °C are expected at the highest TPE fluxes

Structural design and manufacturing of TPE-RX vacuum vessel

Energy Technology Data Exchange (ETDEWEB)

Sago, H.; Orita, J.; Kaguchi, H.; Ishigami, Y. [Mitsubishi Heavy Ind. Ltd., Kobe (Japan); Urata, K.; Kudough, F. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan); Hasegawa, M.; Oyabu, I. [Mitsubishi Electric Co., Tokyo (Japan); Yagi, Y.; Sekine, S.; Shimada, T.; Hirano, Y.; Sakakita, H.; Koguchi, H. [Electrotechnical Laboratory, Tsukuba (Japan)

1999-10-01

TPE-RX is a newly constructed, large-sized reversed field pinch (RFP) machine installed at the Electrotechnical Laboratory of the Ministry of International Trade and Industry in Japan. This is the third largest RFP in the world. Major and minor radii of the plasma are 1.72 and 0.45 m, respectively. TPE-RX aims to optimize plasma confinement up to 1 MA. RFP plasma configuration was successfully obtained in March 1998. This paper reports the structural design and manufacturing of the vacuum vessel of TPE-RX. The supporting system on the bellows sections of the vessel was designed based on a detailed finite element method. The integrity of the vacuum vessel against a plasma disruption has been confirmed using dynamic inelastic analyses. (orig.)

Structural design and manufacturing of TPE-RX vacuum vessel

International Nuclear Information System (INIS)

Sago, H.; Orita, J.; Kaguchi, H.; Ishigami, Y.; Urata, K.; Kudough, F.; Hasegawa, M.; Oyabu, I.; Yagi, Y.; Sekine, S.; Shimada, T.; Hirano, Y.; Sakakita, H.; Koguchi, H.

1999-01-01

TPE-RX is a newly constructed, large-sized reversed field pinch (RFP) machine installed at the Electrotechnical Laboratory of the Ministry of International Trade and Industry in Japan. This is the third largest RFP in the world. Major and minor radii of the plasma are 1.72 and 0.45 m, respectively. TPE-RX aims to optimize plasma confinement up to 1 MA. RFP plasma configuration was successfully obtained in March 1998. This paper reports the structural design and manufacturing of the vacuum vessel of TPE-RX. The supporting system on the bellows sections of the vessel was designed based on a detailed finite element method. The integrity of the vacuum vessel against a plasma disruption has been confirmed using dynamic inelastic analyses. (orig.)

Characteristics of a large reversed field pinch machine, TPE-RX

International Nuclear Information System (INIS)

Yagi, Y.; Shimada, T.; Hirano, Y.; Sekine, S.; Sakakita, H.; Koguchi, H.; Kiyama, S.; Maejima, Y.; Hirota, I.; Hayase, K.; Sato, Y.; Sugisaki, K.; Oyabu, I.; Hasegawa, M.; Yamane, M.; Sato, F.; Kuno, K.; Minato, T.; Kiryu, A.; Takagi, S.; Sako, K.; Kudough, F.; Urata, K.; Orita, J.; Kaguchi, H.; Sago, H.; Ue, K.

1998-01-01

Construction of a new, large reversed field pinch (RFP) machine called TPE-RX was complete at the end of 1997 as a successor of the previous TPE-1RM20 machine at the Electrotechnical Laboratory (ETL). RFP configuration has been successfully obtained in March 1998. The optimization of the operating condition and discharge cleaning of the wall are presently undergoing with the first physics experiments. This paper is the first report of TPE-RX especially on the goals, overall machine characteristics and the present status. Other papers accompanying with this one will present specific topics on the magnetic coil system and the vacuum vessel system. (author)

Characteristics of a large reversed field pinch machine, TPE-RX

Energy Technology Data Exchange (ETDEWEB)

Yagi, Y.; Shimada, T.; Hirano, Y.; Sekine, S.; Sakakita, H.; Koguchi, H.; Kiyama, S.; Maejima, Y.; Hirota, I.; Hayase, K.; Sato, Y.; Sugisaki, K. [Electrotechnical Lab., Tsukuba-shi, Ibaraki (Japan); Oyabu, I.; Hasegawa, M.; Yamane, M.; Sato, F.; Kuno, K.; Minato, T.; Kiryu, A.; Takagi, S.; Sako, K. [Mitsubishi Electric Corp. (Japan); Kudough, F.; Urata, K.; Orita, J.; Kaguchi, H.; Sago, H.; Ue, K. [Mitsubishi Heavy Industries Ltd. (Japan)

1998-07-01

Construction of a new, large reversed field pinch (RFP) machine called TPE-RX was complete at the end of 1997 as a successor of the previous TPE-1RM20 machine at the Electrotechnical Laboratory (ETL). RFP configuration has been successfully obtained in March 1998. The optimization of the operating condition and discharge cleaning of the wall are presently undergoing with the first physics experiments. This paper is the first report of TPE-RX especially on the goals, overall machine characteristics and the present status. Other papers accompanying with this one will present specific topics on the magnetic coil system and the vacuum vessel system. (author)

Design of equilibrium field control coil system of TPE-RX

Energy Technology Data Exchange (ETDEWEB)

Sato, F.; Hasegawa, M.; Yamane, M.; Oyabu, I.; Urata, K.; Kudough, F. [Mitsubishi Fusion Center, Chiyoda-ku, Tokyo (Japan); Minato, T.; Kiryu, A.; Takagi, S.; Kuno, K.; Sako, K. [Mitsubishi Electric Corp. (Japan). Energy and Industrial Systems Center; Hirano, Y.; Yagi, Y.; Shimada, T.; Sekine, S.; Sakakita, H. [Electrotechnical Lab. (Japan)

1998-07-01

The construction of TPE-RX reversed field pinch(RFP) machine at the Electrotechnical Laboratory (ETL) was complete at the end of 1997 and the coil system showed the expected performances on the test at the ETL site. In the reversed field pinch machine, the plasma is surrounded by a thick metal shell to maintain plasma equilibrium and to obtain plasma stability. We designed the coil system considering an error magnetic field which is generated by an iron core and the poloidal shell gap of the thick shell. This paper describes designs and the related studies of the equilibrium field control coil system of TPE-RX. (author)

Design of equilibrium field control coil system of TPE-RX

International Nuclear Information System (INIS)

Sato, F.; Hasegawa, M.; Yamane, M.; Oyabu, I.; Urata, K.; Kudough, F.; Minato, T.; Kiryu, A.; Takagi, S.; Kuno, K.; Sako, K.

1998-01-01

The construction of TPE-RX reversed field pinch(RFP) machine at the Electrotechnical Laboratory (ETL) was complete at the end of 1997 and the coil system showed the expected performances on the test at the ETL site. In the reversed field pinch machine, the plasma is surrounded by a thick metal shell to maintain plasma equilibrium and to obtain plasma stability. We designed the coil system considering an error magnetic field which is generated by an iron core and the poloidal shell gap of the thick shell. This paper describes designs and the related studies of the equilibrium field control coil system of TPE-RX. (author)

TPE/REE separation with the use of zirconium salt of HDBP

Science.gov (United States)

Glekov, R. G.; Shmidt, O. V.; Palenik, Yu. V.; Goletsky, N. D.; Sukhareva, S. Yu.; Fedorov, Yu. S.; Zilberman, B. Ya.

2003-01-01

Partitioning of long-lived radionuclides (minor actinides, fission products) is considered as TBP-compatible ZEALEX-process for extraction separation of transplutonium elements (TPE) and rare-earth elements (REE), as well as Y, Mo, Fe and residual amounts of Np, Pu, U. Zirconium salt of dibutyl phosphoric acid (ZS-HDBP) dissolved in 30 % TBP is used as a solvent. The process was tested in multistage centrifugal contactors. Lanthanides, Y and TPE, as well as Mo, Fe were extracted from high-level Purex raffinate, Am and ceric subgroup of REE being separated from the polyvalent elements by stripping with HNO3. TPE/REE partitioning was achieved in the second cycle of the ZEALEX-process using DTPA in formic acid media. The integral decontamination factor of Am from La and Ce after both cycles is >200, from Pr and Nd 20-30 and from Sm and Eu 3.6; REE strips in both cycles contained <0,1% of the initial amount of TPE.

Confinement characteristics of the TPE reversed field pinch plasmas and effects of the boundary configuration

International Nuclear Information System (INIS)

Yagi, Y.; Maejima, Y.; Zollino, G.

2001-01-01

Confinement characteristics of the TPE series reversed field pinch (RFP) machines, TPE-1RM15, TPE-1RM20 and TPE-1RM20mod, at Electrotechnical Laboratory (ETL) are summarized. Especially data are synthesized in respect to the effects of the different boundary structures of the machines, where shell proximity and overlapped poloidal shell gaps by the multi-layered shell structure are featured. Comparison of the experimental results is shown in terms of the characteristics of magnetic fluctuations, global confinement properties in general, operation capability of the improved confinement in high pinch parameter (Q) discharges and locked mode events. Linear growth rate of the unstable modes as a function of the shell distance is numerically simulated. Understandings of RFP plasma physics have also made progress by the most recent intensive experiments on correlation studies between fast electrons and dynamo activities and measurement of the plasma and mode rotation. TPE-1RM20mod was shutdown in December 1996 and new RFP experiment has started in TPE-RX from March 1998. The new machine also succeeds the concept of the shell configuration of the TPE-1RM20. (author)

Hybrid Rayleigh, Raman and TPE fluorescence spectral confocal microscopy of living cells

NARCIS (Netherlands)

Pully, V.V.; Lenferink, Aufrid T.M.; Otto, Cornelis

2010-01-01

A hybrid fluorescence–Raman confocal microscopy platform is presented, which integrates low-wavenumber-resolution Raman imaging, Rayleigh scatter imaging and two-photon fluorescence (TPE) spectral imaging, fast ‘amplitude-only’ TPE-fluorescence imaging and high-spectral-resolution Raman imaging.

Thermal tuning of a silicon photonic crystal cavity infilled with an elastomer

NARCIS (Netherlands)

Erdamar, A.K.; Van Leest, M.M.; Picken, S.J.; Caro, J.

2011-01-01

Thermal tuning of the transmission of an elastomer infilled photonic crystal cavity is studied. An elastomer has a thermal expansion-induced negative thermo-optic coefficient that leads to a strong decrease of the refractive index upon heating. This property makes elastomer highly suitable for

Development of EPDM based thermoplastic elastomers for oil resistant applications: optimization of radiation grafting parameters

International Nuclear Information System (INIS)

Chaudhari, C.V.; Dubey, K.A.; Bhardwaj, Y.K.; Sabharwal, S.

2008-01-01

Full text: Ethylene-propylene diene terpolymer (EPDM) is currently among the most industrially useful elastomers because of its certain unique properties like excellent heat resistance, resistance towards ozone deterioration, high impact strength. However EPDM has a serious drawback of weak adhesion properties and tendency to swell in contact with paraffin oil and aromatic hydrocarbons. Blending EPDM with suitable polar elastomers or grafting polar polymer chains onto EPDM is an easy method to overcome this drawback. Radiation grafting of Acrylonitrile (ACN) on EPDM provides an easy and effective method of incorporating ACN uniformly on the EPDM backbone. Grafting of ACN on EPDM is expected to result grafted copolymer with better oil resistance, hardness and better compatibility with polar polymer matrices. In the present study radiation induced grafting of ACN onto EPDM rubber film was investigated by mutual radiation grafting technique. Effect of experimental variables viz. radiation dose, dose rate, types of solvents and monomer content on extent of grafting was studied. The solvent composition of Acetone:CCl 4 (20:80) was found to be the optimum mixture which resulted in highest degree of grafting. It was found that the degree of grafting increases with radiation dose, monomer content and decreases with dose rate

Characteristics of the TPE reversed-field pinch plasmas in conventional and improved confinement regimes

International Nuclear Information System (INIS)

Sakakita, H.; Asai, T.; Fiksel, G.; Yagi, Y.; Frassinetti, L.; Hayase, K.; Hirano, Y.; Kiyama, S.; Koguchi, H.; Shimada, T.; Innocente, P.; Spizzo, G.; Terranova, D.; Sato, Y.; Yoshikawa, M.

2005-01-01

We present the characteristics and experimental scaling laws of reversed-field pinch (RFP) plasmas, which are obtained from the recently established toroidal pinch experiment (TPE) database. The database contains information for approximately 1500 discharges consistently selected from four TPE RFP devices, and covers two decades of RFP experiments under conventional operating conditions at the National Institute of Advanced Industrial Science and Technology. We present the physics of the pulsed poloidal current drive (PPCD) discharges in the TPE-RX RFP device, and a comparison of the improved energy confinement time in PPCD, τ E P PCD , with τ E s caling as the reference scaling law (τ E s caling ∼ a 1.63 (I P 0.78 (I P /N) 0.33 Θ 2.97 ) in the TPE database, is attempted. The result shows that τ E P PCD agrees well with τ E s caling because of the strong pinch parameter dependence on the TPE scaling law. A potential improved confinement mode in the quasi-single-helicity (QSH) state is also investigated in TPE-RX, with respect to the operation conditions under which the QSH spontaneously appears in the core region, where a typical island structure is observed by means of soft Xray tomography. (author)

Possible Applications of 3D Printing Technology on Textile Substrates

Science.gov (United States)

Korger, M.; Bergschneider, J.; Lutz, M.; Mahltig, B.; Finsterbusch, K.; Rabe, M.

2016-07-01

3D printing is a rapidly emerging additive manufacturing technology which can offer cost efficiency and flexibility in product development and production. In textile production 3D printing can also serve as an add-on process to apply 3D structures on textiles. In this study the low-cost fused deposition modeling (FDM) technique was applied using different thermoplastic printing materials available on the market with focus on flexible filaments such as thermoplastic elastomers (TPE) or Soft PLA. Since a good adhesion and stability of the 3D printed structures on textiles are essential, separation force and abrasion resistance tests were conducted with different kinds of printed woven fabrics demonstrating that a sufficient adhesion can be achieved. The main influencing factor can be attributed to the topography of the textile surface affected by the weave, roughness and hairiness offering formlocking connections followed by the wettability of the textile surface by the molten polymer, which depends on the textile surface energy and can be specifically controlled by washing (desizing), finishing or plasma treatment of the textile before the print. These basic adhesion mechanisms can also be considered crucial for 3D printing on knitwear.

Techniques for hot embossing microstructures on liquid silicone rubbers with fillers

DEFF Research Database (Denmark)

Vudayagiri, Sindhu; Yu, Liyun; Skov, Anne Ladegaard

2015-01-01

Embossing is an established process for the thermoplastic elastomers but not yet for the thermosetting elastomers. It has already been shown that hot embossing is a viable technology for imprinting microstructures in addition to curing thin silicone films at their gel point. It is one of the simp......Embossing is an established process for the thermoplastic elastomers but not yet for the thermosetting elastomers. It has already been shown that hot embossing is a viable technology for imprinting microstructures in addition to curing thin silicone films at their gel point. It is one...

Behavioral variation by ionizing irradiation of recycled thermoplastic elastomer reinforced with natural fibers or inorganic fillers

International Nuclear Information System (INIS)

Mohamed, H.A.A.

2015-01-01

Plastics are organic polymeric materials consisting of giant organic molecules. Plastic materials can be formed into shapes by one of a variety of processes, such as extrusion, molding, casting or spinning. Modern plastics possess a number of extremely desirable characteristics; high strength to weight ratio, excellent thermal properties, electrical insulation, resistance to acids, alkalis and solvents. These polymers are made of a series of repeating units known as monomers. The structure and degree of polymerisation of a given polymer determine its characteristics. Linear polymers, a single linear chain of monomers, and branched polymers, linear with side chains, are thermoplastic that is they soften when heated. Thermoplastics make up 80% of the plastics produced today. Examples of thermoplastics include: • High density polyethylene (HDPE) used in piping, automotive fuel tanks, bottles, toys, • Low density polyethylene (LDPE) used in plastic bags, cling film, flexible containers; • Polyethylene terephthalate (PET) used in bottles, carpets and food packaging; • Polypropylene (PP) used in food containers, battery cases, bottle crates, automotive parts and fibers; • Polystyrene (PS) used in dairy product containers, tape cassettes, cups and plates; • Polyvinyl chloride (PVC) used in window frames, flooring, bottles, packaging film, cable insulation, credit cards and medical products.

Effect of natural ageing on surface of silver loaded TPE and its influence in antimicrobial efficacy

Energy Technology Data Exchange (ETDEWEB)

Tomacheski, Daiane, E-mail: daitomacheski@gmail.com [Department of Materials Engineering, Laboratory of Polymers – LAPOL, Universidade Federal do Rio Grande do Sul, UFRGS, 9500 Bento Gonçalves Avenue, Postal Code 15010, Porto Alegre 91501-970 (Brazil); Softer Brasil Compostos Termoplásticos LTDA, 275 Edgar Hoffmeister Avenue, Campo Bom 93700-000 (Brazil); Pittol, Michele [Softer Brasil Compostos Termoplásticos LTDA, 275 Edgar Hoffmeister Avenue, Campo Bom 93700-000 (Brazil); Simões, Douglas Naue; Ribeiro, Vanda Ferreira [Department of Materials Engineering, Laboratory of Polymers – LAPOL, Universidade Federal do Rio Grande do Sul, UFRGS, 9500 Bento Gonçalves Avenue, Postal Code 15010, Porto Alegre 91501-970 (Brazil); Softer Brasil Compostos Termoplásticos LTDA, 275 Edgar Hoffmeister Avenue, Campo Bom 93700-000 (Brazil); Santana, Ruth Marlene Campomanes [Department of Materials Engineering, Laboratory of Polymers – LAPOL, Universidade Federal do Rio Grande do Sul, UFRGS, 9500 Bento Gonçalves Avenue, Postal Code 15010, Porto Alegre 91501-970 (Brazil)

2017-05-31

Highlights: • Ag loaded TPE lost their antimicrobial efficacy after polymer degradation. • Modifications in Ag loaded TPE surface provide conditions to bacteria settlement. • Rough TPE surface and the low γ{sub S}{sup +} was more favorable for bacterial development. - Abstract: The aim of this study is to characterize the modifications in silver loaded TPE surfaces exposed to weathering and their relation to susceptibility to microbial attack. Silver loaded TPE materials were exposed to natural ageing for nine months and modifications in antimicrobial properties and surface characteristics were evaluated. Chemical changes were investigated by using the infrared spectra. The average surface roughness and topography were determined by atomic force microscopy. Contact angle was measured to verify wettability conditions and surface free energy (SFE). After nine months of exposure, a decrease in the antimicrobial properties of loaded TPE compounds was observed. A reduction in surface roughness and improvement in wettability and high values of polar component of SFE were verified. The best antibacterial action was noticed in the sample with high Lewis acid force, lower roughness and lower carbonyl index.

A disposable and multifunctional capsule for easy operation of microfluidic elastomer systems

International Nuclear Information System (INIS)

Thorslund, Sara; Läräng, Thomas; Kreuger, Johan; Nguyen, Hugo; Barkefors, Irmeli

2011-01-01

The global lab-on-chip and microfluidic markets for cell-based assays have been predicted to grow considerably, as novel microfluidic systems enable cell biologists to perform in vitro experiments at an unprecedented level of experimental control. Nevertheless, microfluidic assays must, in order to compete with conventional assays, be made available at easily affordable costs, and in addition be made simple to operate for users having no previous experience with microfluidics. We have to this end developed a multifunctional microfluidic capsule that can be mass-produced at low cost in thermoplastic material. The capsule enables straightforward operation of elastomer inserts of optional design, here exemplified with insert designs for molecular gradient formation in microfluidic cell culture systems. The integrated macro–micro interface of the capsule ensures reliable connection of the elastomer fluidic structures to an external perfusion system. A separate compartment in the capsule filled with superabsorbent material is used for internal waste absorption. The capsule assembly process is made easy by integrated snap-fits, and samples within the closed capsule can be analyzed using both inverted and upright microscopes. Taken together, the capsule concept presented here could help accelerate the use of microfluidic-based biological assays in the life science sector. (technical note)

Free-volume micro-structure of the amorphous polymers at Tg

International Nuclear Information System (INIS)

Bartos, J.

1995-01-01

The positron annihilation spectroscopy was used to the study of the free-volume microstructure of the amorphous polymers [diene-elastomers, vinyl-elastomers and thermoplastics, aromatic thermoplastics

76 FR 61255 - Airworthiness Directives; Honeywell International Inc. TPE331 Model Turboprop Engines With...

Science.gov (United States)

2011-10-04

... Certification Office, FAA, Atlanta Aircraft Certification Office, 1701 Columbia Avenue, College Park, GA 30337... Airworthiness Directives; Honeywell International Inc. TPE331 Model Turboprop Engines With Certain Dixie... Honeywell International Inc. TPE331 model turboprop engines with a part manufacturer approval (PMA...

The synthesis of structure and parametrical identification of mathematical model of process of a stitching of active copolymers when receiving a treelike thermoelastolayers

Directory of Open Access Journals (Sweden)

S. G. Tikhomirov

2017-01-01

Full Text Available Thermoplastic elastomers are a promising class of polymeric materials whose properties are close to those of conventional rubbers. Thermoplastic elastomers are recycled by high-performance methods used to process plastics in contrast to ordinary rubbers. Also thermoplastic elastomers exclude the stage of vulcanization from the technological scheme and they are capable of multiple processing. The problem of modeling of the kinetics of the crosslinking process in the preparation of a thermal elastoplast with a treelike structures was formulated and solved. The polyfunctional coupling agent used as crosslinking agent for crosslinking of diblock to produce thermoplastic elastomers with a treelike structures. A kinetic scheme of the coupling process is proposed. It based on the available experimental data on the molecular weight distribution of thermoplastic elastomers and the analysis of various combinations of polymer molecules. The scheme takes into account the possibility of attaching the active diblock to each functional group of the combining agent molecule of different structures. The mathematical model of the process taking place in the reactor of an ideal mixing of a periodic action is represented of the system in the form of differential equations. Modeling the process, it is assumed that the rate of the coupling reaction depends on the mobility of the molecules which enter into the reaction. The sum of the squares of the discrepancy of experimentally determined and theoretically predicted concentrations of thermoplastic elastomers of each structure is adopted as an optimality criterion for solving the problem of parametric identification. The computational experiment showed that the combining agent reacts with the active diblock mainly in two and three functional groups. The synthesized model allows to evaluate the concentration of the coupling agent, polystyrene-polybutadiene-lithium and thermoplastic elastomer with different molecular

A novel dynamic cardiac simulator utilizing pneumatic artificial muscle.

Science.gov (United States)

Liu, Hao; Yan, Jie; Zhou, Yuanyuan; Li, Hongyi; Li, Changji

2013-01-01

With the development of methods and skills of minimally invasive surgeries, equipments for doctors' training and practicing are in high demands. Especially for the cardiovascular surgeries, operators are requested to be familiar with the surgical environment of a beating heart. In this paper, we present a new dynamic cardiac simulator utilizing pneumatic artificial muscle to realize heartbeat. It's an artificial left ventricular of which the inner chamber is made of thermoplastic elastomers (TPE) with an anatomical structure of the real human heart. It is covered by another layer of material forming the artificial muscle which actuates the systole and diastole uniformly and omnidirectionally as the cardiac muscle does. Preliminary experiments were conducted to evaluate the performance of the simulator. The results indicated that the pressure at the terminal of the aorta could be controlled within the range of normal human systolic pressure, which quantitatively validated the new actuating mode of the heart-beating is effective.

Study of mechanical and thermal properties of soy flour elastomers

Science.gov (United States)

Allen, Kendra Alicia

Bio-based plastics are becoming viable alternatives to petroleum-based plastics because they decrease dependence on petroleum derivatives and are more environmentally friendly. Raw materials such as soy flour are widely available, low cost, lightweight, stiffness and have high strength characteristics, but weak interfacial adhesion between the soy flour and the polymer poses a challenge. In this study, soy flour was utilized as a filler in thermoplastic elastomer composites. A surface modification called acetylation was investigated at soy flour concentrations of 10 wt%, 15 wt% and 20 wt%. The mechanical properties of the composites were then compared to that of elastomers without a filler. Chemical characterization of the acetylated soy flour was attempted in order to understand what occurs during the reaction and after completion. In the range of tests, soy flour loadings were observed to be inversely proportional to tensile strength for both the untreated and treated soy flour. However, the acetylated soy flour at 10 wt% concentration performed comparable to that of the neat rubber and resulted in an increase in tensile strength. Unexpectedly, the acetylation reaction increased elongation, which reduced stress within the composite and is believed to increase the adhesion of the soy flour to that of the elastomer. In the nuclear magnetic resonance (SS-NMR), the intensity for the treated soy flour was larger than that of the untreated soy flour for the acetyl groups that were attached to the soy flour, particularly, the carbonyl function group next to the deprotonated oxygen and the methyl group next to the carbonyl. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) indicated that the acetylated soy flour is slightly more thermally stable than the untreated soy flour. The treated soy flour also increased the decomposition temperature of the composite.

Silicone-based Dielectric Elastomers

DEFF Research Database (Denmark)

Skov, Anne Ladegaard

Efficient conversion of energy from one form to another (transduction) is an important topic in our daily day, and it is a necessity in moving away from the fossil based society. Dielectric elastomers hold great promise as soft transducers, since they are compliant and light-weight amongst many...... energy efficient solutions are highly sought. These properties allow for interesting products ranging very broadly, e.g. from eye implants over artificial skins over soft robotics to huge wave energy harvesting plants. All these products utilize the inherent softness and compliance of the dielectric...... elastomer transducers. The subject of this thesis is improvement of properties of silicone-based dielectric elastomers with special focus on design guides towards electrically, mechanically, and electromechanically reliable elastomers. Strategies for improving dielectric elastomer performance are widely...

Distributed Manufacturing of Flexible Products: Technical Feasibility and Economic Viability

Directory of Open Access Journals (Sweden)

Aubrey L. Woern

2017-10-01

Full Text Available Distributed manufacturing even at the household level is now well established with the combined use of open source designs and self-replicating rapid prototyper (RepRap 3-D printers. Previous work has shown substantial economic consumer benefits for producing their own polymer products. Now flexible filaments are available at roughly 3-times the cost of more conventional 3-D printing materials. To provide some insight into the potential for flexible filament to be both technically feasible and economically viable for distributed digital manufacturing at the consumer level this study investigates 20 common flexible household products. The 3-D printed products were quantified by print time, electrical energy use and filament consumption by mass to determine the cost to fabricate with a commercial RepRap 3-D printer. Printed parts were inspected and when necessary tested for their targeted application to ensure technical feasibility. Then, the experimentally measured cost to DIY manufacturers was compared to low and high market prices for comparable commercially available products. In addition, the mark-up and potential for long-term price declines was estimated for flexible filaments by converting thermoplastic elastomer (TPE pellets into filament and reground TPE from a local recycling center into filament using an open source recyclebot. This study found that commercial flexible filament is economically as well as technically feasible for providing a means of distributed home-scale manufacturing of flexible products. The results found a 75% savings when compared to the least expensive commercially equivalent products and 92% when compared to high market priced products. Roughly, 160 flexible objects must be substituted to recover the capital costs to print flexible materials. However, as previous work has shown the Lulzbot Mini 3-D printer used in this study would provide more than a 100% ROI printing one object a week from hard thermoplastics

Asymmetric Dielectric Elastomer Composite Material

Science.gov (United States)

Stewart, Brian K. (Inventor)

2014-01-01

Embodiments of the invention provide a dielectric elastomer composite material comprising a plurality of elastomer-coated electrodes arranged in an assembly. Embodiments of the invention provide improved force output over prior DEs by producing thinner spacing between electrode surfaces. This is accomplished by coating electrodes directly with uncured elastomer in liquid form and then assembling a finished component (which may be termed an actuator) from coated electrode components.

Hysteretic behavior of soft magnetic elastomer composites

Energy Technology Data Exchange (ETDEWEB)

Krautz, Maria; Werner, David [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Schrödner, Mario [Thuringian Institute of Textile and Plastics Research e.V., Breitscheidstraße 97, D-07407 Rudolstadt (Germany); Funk, Alexander [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Jantz, Alexander; Popp, Jana [Thuringian Institute of Textile and Plastics Research e.V., Breitscheidstraße 97, D-07407 Rudolstadt (Germany); Eckert, Jürgen [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstraße 12, A-8700 Leoben (Austria); Department of Materials Physics, Montanuniversität Leoben, Jahnstraße 12, A-8700 Leoben (Austria); Waske, Anja [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany)

2017-03-15

Composites of polymer and micron-sized particles of carbonyl-iron were investigated in terms of their magnetization behavior. Thermoplastic elastomers with varying Young's modulus (E{sub Polymer}=0.14–14.6 MPa) were used as matrix material. Field dependent magnetization curves reveal that the hysteretic behavior of the composites strongly depends on both the particle fraction (7, 10, 14, 21, 31 vol%) and on the mechanical properties of the polymer. It is shown that hysteresis only appears above a certain fraction of magnetic particles which can be accounted to the magnetic exchange between the particles. However, hysteresis is suppressed in the composite with largest Young's modulus of the polymer matrix, even at largest particle fraction. - Highlights: • Composites with soft magnetic Iron Particles show hysteretic magnetization behavior. • Origin of the hysteresis is the alignment of particles along field direction. • Hysteresis depends on both, mechanical properties of matrix and particle fraction.

Evaluation of Tp-E Interval and Tp-E/QT Ratio in Patients with Aortic Stenosis.

Science.gov (United States)

Yayla, Çağrı; Bilgin, Murat; Akboğa, Mehmet Kadri; Gayretli Yayla, Kadriye; Canpolat, Uğur; Dinç Asarcikli, Lale; Doğan, Mehmet; Turak, Osman; Çay, Serkan; Özeke, Özcan; Akyel, Ahmet; Yeter, Ekrem; Aydoğdu, Sinan

2016-05-01

The risk of syncope and sudden cardiac death due to ventricular arrhythmias increased in patients with aortic stenosis (AS). Recently, it was shown that Tp-e interval, Tp-e/QT, and Tp-e/QTc ratio can be novel indicators for prediction of ventricular arrhythmias and mortality. We aimed to investigate the association between AS and ventricular repolarization using Tp-e interval and Tp-e/QT ratio. Totally, 105 patients with AS and 60 control subjects were enrolled to this study. The severity of AS was defined by transthoracic echocardiographic examination. Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were measured from the 12-lead electrocardiogram. Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were significantly increased in parallel to the severity of AS (P ratio had significant positive correlation with mean aortic gradient (r = 0.192, P = 0.049). In multivariate logistic regression analysis, Tp-e/QTc ratio and left ventricular mass were found to be independent predictors of severe AS (P = 0.03 and P = 0.04, respectively). Our study showed that Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios were increased in patients with severe AS. Tp-e/QTc ratio and left ventricular mass were found as independent predictors of severe AS. © 2015 Wiley Periodicals, Inc.

Joining of thermoplastic substrates by microwaves

Science.gov (United States)

Paulauskas, Felix L.; Meek, Thomas T.

1997-01-01

A method for joining two or more items having surfaces of thermoplastic material includes the steps of depositing an electrically-conductive material upon the thermoplastic surface of at least one of the items, and then placing the other of the two items adjacent the one item so that the deposited material is in intimate contact with the surfaces of both the one and the other items. The deposited material and the thermoplastic surfaces contacted thereby are then exposed to microwave radiation so that the thermoplastic surfaces in contact with the deposited material melt, and then pressure is applied to the two items so that the melted thermoplastic surfaces fuse to one another. Upon discontinuance of the exposure to the microwave energy, and after permitting the thermoplastic surfaces to cool from the melted condition, the two items are joined together by the fused thermoplastic surfaces. The deposited material has a thickness which is preferably no greater than a skin depth, .delta..sub.s, which is related to the frequency of the microwave radiation and characteristics of the deposited material in accordance with an equation.

High-strain actuator materials based on dielectric elastomers

DEFF Research Database (Denmark)

Pelrine, R.; Kornbluh, R.; Kofod, G.

2000-01-01

Dielectric elastomers are a new class of actuator materials that exhibit excellent performance. The principle of operation, as well as methods to fabricate and test these elastomers, is summarized here. The Figure is a sketch of an elastomer film (light gray) stretched on a frame (black) and patt......Dielectric elastomers are a new class of actuator materials that exhibit excellent performance. The principle of operation, as well as methods to fabricate and test these elastomers, is summarized here. The Figure is a sketch of an elastomer film (light gray) stretched on a frame (black...

Segmented poly(ether ester)s and poly(ether ester amide)s for use in tissue engineering

NARCIS (Netherlands)

Deschamps, A.A.

2002-01-01

The objective of the studies described in this thesis is to investigate the applicability of these slowly degradable thermoplastic elastomers as scaffolds for tissue engineering, with emphasis on their phase separation and degradation properties. A second thermoplastic elastomer in which the

Functionalized Materials From Elastomers to High Performance Thermoplastics

Energy Technology Data Exchange (ETDEWEB)

Salazar, Laura Ann [Iowa State Univ., Ames, IA (United States)

2003-01-01

Synthesis and incorporation of functionalized materials continues to generate significant research interest in academia and in industry. If chosen correctly, a functional group when incorporated into a polymer can deliver enhanced properties, such as adhesion, water solubility, thermal stability, etc. The utility of these new materials has been demonstrated in drug-delivery systems, coatings, membranes and compatibilizers. Two approaches exist to functionalize a material. The desired moiety can be added to the monomer either before or after polymerization. The polymers used range from low glass transition temperature elastomers to high glass transition temperature, high performance materials. One industrial example of the first approach is the synthesis of Teflon(reg. sign). Poly(tetrafluoroethylene) (PTFE or Teflon(reg. sign)) is synthesized from tetrafluoroethylene, a functionalized monomer. The resulting material has significant property differences from the parent, poly(ethylene). Due to the fluorine in the polymer, PTFE has excellent solvent and heat resistance, a low surface energy and a low coefficient of friction. This allows the material to be used in high temperature applications where the surface needs to be nonabrasive and nonstick. This material has a wide spread use in the cooking industry because it allows for ease of cooking and cleaning as a nonstick coating on cookware. One of the best examples of the second approach, functionalization after polymerization, is the vulcanization process used to make tires. Natural rubber (from the Hevea brasiliensis) has a very low glass transition temperature, is very tacky and would not be useful to make tires without synthetic alteration. Goodyear's invention was the vulcanization of polyisoprene by crosslinking the material with sulfur to create a rubber that was tough enough to withstand the elements of weather and road conditions. Due to the development of polymerization techniques to make cis

Piezoresistive Soft Condensed Matter Sensor for Body-Mounted Vital Function Applications

Directory of Open Access Journals (Sweden)

Mark Melnykowycz

2016-03-01

Full Text Available A soft condensed matter sensor (SCMS designed to measure strains on the human body is presented. The hybrid material based on carbon black (CB and a thermoplastic elastomer (TPE was bonded to a textile elastic band and used as a sensor on the human wrist to measure hand motion by detecting the movement of tendons in the wrist. Additionally it was able to track the blood pulse wave of a person, allowing for the determination of pulse wave peaks corresponding to the systole and diastole blood pressures in order to calculate the heart rate. Sensor characterization was done using mechanical cycle testing, and the band sensor achieved a gauge factor of 4–6.3 while displaying low signal relaxation when held at a strain levels. Near-linear signal performance was displayed when loading to successively higher strain levels up to 50% strain.

Development of Ankle Foot Orthosis (AFO Using Pneumatic Artificial Muscle for Disabled Children

Directory of Open Access Journals (Sweden)

Ishak N.Z.

2017-01-01

Full Text Available Ankle foot orthosis (AFO are commonly used to correct the instabilities and joint weakness of lower limb. In this research, AFO was developed by using pneumatic artificial muscle (PAM to prevent plantarflexion to occur and also to correct the foot from the inversion syndrome. The research started with designing the AFO by using SolidWorks software based on anthropometry measurement data (n=5, age=12 years old. The mechanical simulation was conducted by using Autodesk Inventor software to obtain a safety factor before the fabrication process was conducted. The AFO was fabricated using 3D printer and the thermoplastic elastomer (TPE rubber was selected as the material. PAM was tested by using test bed machine to generate the force and contraction by muscle. The result shows that the PAM was suitable for low speed as the displacement was greater. The AFO could be valuable for the gait rehabilitation.

Performance and reliability of TPE-2 device with pulsed high power source

International Nuclear Information System (INIS)

Sato, Y.; Takeda, S.; Kiyama, S.

1987-01-01

The performance and the reliability of TPE-2 device with pulsed high power sources are described. To obtain the stable high beta plasma, the reproducibility and the reliability of the pulsed power sources must be maintained. A new power crowbar system with high efficiency and the switches with low jitter time are adopted to the bank system. A monitor system which always watches the operational states of the switches is developed too, and applied for the fast rising capacitor banks of TPE-2 device. The reliable operation for the bank has been realized, based on the data of switch monitor system

A Soft Gripper with Rigidity Tunable Elastomer Strips as Ligaments.

Science.gov (United States)

Nasab, Amir Mohammadi; Sabzehzar, Amin; Tatari, Milad; Majidi, Carmel; Shan, Wanliang

2017-12-01

Like their natural counterparts, soft bioinspired robots capable of actively tuning their mechanical rigidity can rapidly transition between a broad range of motor tasks-from lifting heavy loads to dexterous manipulation of delicate objects. Reversible rigidity tuning also enables soft robot actuators to reroute their internal loading and alter their mode of deformation in response to intrinsic activation. In this study, we demonstrate this principle with a three-fingered pneumatic gripper that contains "programmable" ligaments that change stiffness when activated with electrical current. The ligaments are composed of a conductive, thermoplastic elastomer composite that reversibly softens under resistive heating. Depending on which ligaments are activated, the gripper will bend inward to pick up an object, bend laterally to twist it, and bend outward to release it. All of the gripper motions are generated with a single pneumatic source of pressure. An activation-deactivation cycle can be completed within 15 s. The ability to incorporate electrically programmable ligaments in a pneumatic or hydraulic actuator has the potential to enhance versatility and reduce dependency on tubing and valves.

Novel silicone elastomer formulations for DEAPs

DEFF Research Database (Denmark)

Skov, Anne Ladegaard; Vudayagiri, Sindhu; Benslimane, Mohamed

2013-01-01

We demonstrate that the force output and work density of polydimethylsiloxane (PDMS) based dielectric elastomer transducers can be significantly enhanced by the addition of high permittivity titanium dioxide nanoparticles which was also shown by Stoyanov et al[1] for pre-stretched elastomers...... and by Carpi et al for RTV silicones[2]. Furthermore the elastomer matrix is optimized to give very high breakdown strengths. We obtain an increase in the dielectric permittivity of a factor of approximately 2 with a loading of 12% TiO2 particles compared to the pure modified silicone elastomer with breakdown...

Confinement in TPE-RX reversed field pinch

International Nuclear Information System (INIS)

Yagi, Y.; Bolzonella, T.; Canton, A.

2001-01-01

Characteristics of the confinement properties of a reversed field pinch (RFP), the TPE-RX (R/a=1.72/0.45 m, R and a are major and minor radii), are presented for the plasma current, I p of 0.2-0.4 MA. TPE-RX has been operational since 1998, and I p =0.5 MA and duration time of up to 0.1 s have been obtained separately. It is found that I p /N (=12x10 -14 Am, N is the line density) is higher than those of other RFPs and poloidal beta, β p , and energy confinement time, τ E , are 5-10% and 0.5-1 ms, respectively, which are comparable with those of other RFPs of comparable sizes (RFX and MST). Pulsed poloidal current drive has recently been tested and the result has shown a twofold improvement of β p and τ E . The improvement is discussed in terms of the dynamic trajectories in the F-Θ plane, where F and Θ are reversal and pinch parameters, respectively. The global confinement properties are compared between the locked and non-locked discharges, which yields a better understanding of the mode-locking phenomena in RFP plasmas. (author)

Evaluation of Tp-e interval and Tp-e/QT ratio in patients with ankylosing spondylitis.

Science.gov (United States)

Acar, Gurkan; Yorgun, Hikmet; Inci, Mehmet Fatih; Akkoyun, Murat; Bakan, Betul; Nacar, Alper Bugra; Dirnak, Imran; Cetin, Gozde Yildirim; Bozoglan, Orhan

2014-03-01

Ankylosing spondylitis (AS) is a chronic multi-systemic inflammatory rheumatic disorder. Several studies have suggested that the interval from the peak to the end of the electrocardiographic T wave (Tp-e) may correspond to the transmural dispersion of repolarization and that increased Tp-e interval and Tp-e/QT ratio are associated with malignant ventricular arrhythmias. The aim of this study was to evaluate ventricular repolarization by using Tp-e interval and Tp-e/QT ratio in patients with AS, and to assess the relation with inflammation. Sixty-two patients with AS and 50 controls were included. Tp-e interval and Tp-e/QT ratio were measured from a 12-lead electrocardiogram, and the Tp-e interval corrected for heart rate. The plasma level of high sensitive C-reactive protein (hsCRP) was measured. These parameters were compared between groups. In electrocardiographic parameters analysis, QT dispersion (QTd) and corrected QTd were significantly increased in AS patients compared to the controls (31.7 ± 9.6 vs 28.2 ± 7.4 and 35.8 ± 11.5 vs 30.6 ± 7.9 ms, P = 0.03 and P = 0.007, respectively). cTp-e interval and Tp-e/QT ratio were also significantly higher in AS patients (92.1 ± 10.2 vs 75.8 ± 8.4 and 0.22 ± 0.02 vs 0.19 ± 0.02 ms, all P values ratio were significantly correlated with hsCRP (r = 0.63, P ratio were increased in AS patients. These electrocardiographic ventricular repolarization indexes were significantly correlated with the plasma level of hsCRP.

Mechanical design handbook for elastomers. [the design of elastomer dampers for application in rotating machinery

Science.gov (United States)

Darlow, M.; Zorzi, E.

1981-01-01

A comprehensive guide for the design of elastomer dampers for application in rotating machinery is presented. Theoretical discussions, a step by step procedure for the design of elastomer dampers, and detailed examples of actual elastomer damper applications are included. Dynamic and general physical properties of elastomers are discussed along with measurement techniques.

Mechanical Design Handbook for Elastomers

Science.gov (United States)

Darlow, M.; Zorzi, E.

1986-01-01

Mechanical Design Handbook for Elastomers reviews state of art in elastomer-damper technology with particular emphasis on applications of highspeed rotor dampers. Self-contained reference but includes some theoretical discussion to help reader understand how and why dampers used for rotating machines. Handbook presents step-by-step procedure for design of elastomer dampers and detailed examples of actual elastomer damper applications.

Elastomer Reinforced with Carbon Nanotubes

Science.gov (United States)

Hudson, Jared L.; Krishnamoorti, Ramanan

2009-01-01

Elastomers are reinforced with functionalized, single-walled carbon nanotubes (SWNTs) giving them high-breaking strain levels and low densities. Cross-linked elastomers are prepared using amine-terminated, poly(dimethylsiloxane) (PDMS), with an average molecular weight of 5,000 daltons, and a functionalized SWNT. Cross-link densities, estimated on the basis of swelling data in toluene (a dispersing solvent) indicated that the polymer underwent cross-linking at the ends of the chains. This thermally initiated cross-linking was found to occur only in the presence of the aryl alcohol functionalized SWNTs. The cross-link could have been via a hydrogen-bonding mechanism between the amine and the free hydroxyl group, or via attack of the amine on the ester linage to form an amide. Tensile properties examined at room temperature indicate a three-fold increase in the tensile modulus of the elastomer, with rupture and failure of the elastomer occurring at a strain of 6.5.

Self-healing elastomer system

Science.gov (United States)

Keller, Michael W. (Inventor); Sottos, Nancy R. (Inventor); White, Scott R. (Inventor)

2009-01-01

A composite material includes an elastomer matrix, a set of first capsules containing a polymerizer, and a set of second capsules containing a corresponding activator for the polymerizer. The polymerizer may be a polymerizer for an elastomer. The composite material may be prepared by combining a first set of capsules containing a polymerizer, a second set of capsules containing a corresponding activator for the polymerizer, and a matrix precursor, and then solidifying the matrix precursor to form an elastomeric matrix.

Thermodynamics and instability of dielectric elastomer (Conference Presentation)

Science.gov (United States)

Liu, Liwu; Liu, Yanju; Leng, Jinsong; Mu, Tong

2017-04-01

Dielectric elastomer is a kind of typical soft active material. It can deform obviously when subjected to an external voltage. When a dielectric elastomer with randomly oriented dipoles is subject to an electric field, the dipoles will rotate to and align with the electric field. The polarization of the dielectric elastomer may be saturated when the voltage is high enough. When subjected to a mechanical force, the end-to-end distance of each polymer chain, which has a finite contour length, will approach the finite value, reaching a limiting stretch. On approaching the limiting stretch, the elastomer stiffens steeply. Here, we develop a thermodynamic constitutive model of dielectric elastomers undergoing polarization saturation and strain-stiffening, and then investigate the stability (electromechanical stability, snap-through stability) and voltage induced deformation of dielectric elastomers. Analytical solution has been obtained and it reveals the marked influence of the extension limit and polarization saturation limit on its instability. The developed thermodynamic constitutive model and simulation results would be helpful in future to the research of dielectric elastomer based high-performance transducers.

Data processing system for ETL TPE-2

International Nuclear Information System (INIS)

Yahagi, E.; Kiyama, M.

1988-01-01

The data processing system for ETL TPE-2 consists of 2 CPU systems and it is composing a duplex system. One system is used as a data acquisition system, which is abbreviated as DAS and functions controlling various data input devices, data acquisition, communication with the main controller of TPE-2 confirming safety system operation. Another one is used as data processing system, which is abbreviated as DPS and functions the processing of the data after the acquisition, the interconnections with the mainframe and the development of software. A transient memory system, which has 64 channels of 8 bits ADC with maximum sampling frequency of 20 MHz and 4 KB buffer memory in each channel, is used to record the time sequential experimental data. Two CAMAC crates are used for the acquisition of the informations of the experiment condition and Thomson scattering data. They are composing a serial high way system through fiber optics. The CAMAC crate for Thomson scattering data is controlled by a personal computer, HP-85, and is available stand-alone use, and the communication between the CAMAC system and DAS is easily performed by using a CAMAC memory module as an intermediator without complicated procedure in the connection of different type computers. Two magnetic disk pack units, which have the formatted storage capacity of 158 KB in each one and can record the data over 2,000 shots, are used in parallel with a magnetic tape handler for the data file. Thus we realized the high speed data processing over the wide range of experimental shots and confirmed the preservation of the data. (author)

An all-polymer airflow sensor using a piezoresistive composite elastomer

International Nuclear Information System (INIS)

Aiyar, Avishek R; Allen, Mark G; Song, Chao; Kim, Seong-Hyok

2009-01-01

This paper presents an all-polymer flexible micromachined flow sensor using a carbon-black based conductive composite elastomer as a piezoresistor. The device is composed of an out-of-plane curved flow sensing element formed using a polyimide film. The conductive composite elastomer combines a low Young's modulus (∼1.72 MPa) and a high piezoresistive gage factor (∼7.3), making it an ideal material for the sensing application. Moreover, the use of the polyimide film, which can be easily laser micromachined, as the material for device fabrication enables the use of planar micromachining techniques, which minimizes process complexities. The proposed fabrication sequence combines the benefits of the polymeric materials used, while simultaneously enabling a backside interconnect scheme for an array of devices, without additional processing steps. The backside interconnect scheme allows for flow field mapping with minimum interference due to the sensing circuitry. Individual sensors as small as 1.5 mm in length and 0.4 mm in width, with 70 µm wide and 20–50 µm thick piezoresistor lines, have been fabricated. Wind tunnel testing demonstrated sensitivities as high as 66Ω/(m s −1 ). The integration of polyimide films and conductive elastomers into a flow sensing device using the simple planar fabrication technologies discussed is suitable for reduced cost, large area sensor array development, and can also leverage traditional flexible circuit fabrication

Segmented poly(ether ester)s and poly(ether ester amide)s for use in tissue engineering

OpenAIRE

Deschamps, A.A.

2002-01-01

The objective of the studies described in this thesis is to investigate the applicability of these slowly degradable thermoplastic elastomers as scaffolds for tissue engineering, with emphasis on their phase separation and degradation properties. A second thermoplastic elastomer in which the terephthalic moieties have been replaced by ester-amide segments, is also investigated for use in scaffolding.

Weibull Analysis of Electrical Breakdown Strength as an Effective Means of Evaluating Elastomer Thin Film Quality

DEFF Research Database (Denmark)

Silau, Harald; Stabell, Nicolai Bogø; Petersen, Frederik Riddersholm

2018-01-01

To realize the commercial potential of dielectric elastomers, reliable, large-scale film production is required. Ensuring proper mixing and subsequently avoiding demixing after, for example, pumping and coating of elastomer premix in an online process is not facile. Weibull analysis...... of the electrical breakdown strength of dielectric elastomer films is shown to be an effective means of evaluating the film quality. The analysis is shown to be capable of distinguishing between proper and improper mixing schemes where similar analysis of ultimate mechanical properties fails to distinguish....

Patterning conductive PDMS nanocomposite in an elastomer using microcontact printing

International Nuclear Information System (INIS)

Liu, Chao-Xuan; Choi, Jin-Woo

2009-01-01

This paper introduces a simple method of embedding conductive and flexible elastomer micropatterns into a bulk elastomer. Employing microcontact printing and cast molding techniques, patterns consisting of conductive poly(dimethylsiloxane) (PDMS) composites mixed with multi-walled carbon nanotubes (MWCNTs) are embedded into bulk PDMS to form all-elastomer devices. To pattern conductive composites, a micromachined printing mold is utilized to transfer composite ink from a spin-coated thin layer to another substrate. Distinct from previously reported approaches, the printing mold in this technique, once fabricated, can be repeatedly used to generate new patterns and therefore greatly simplifies the device fabrication process and improves its efficiency. Manufactured devices with embedded conductive patterns exhibit excellent mechanical flexibility. With characterization of printing reliability, electrical conductivity of the composites is also shown with different loading percentages of MWCNTs. Furthermore, a simple strain gauge was fabricated and tested to demonstrate the potential applications of embedded conductive patterns. Overall, this approach demonstrates feasibility to be a simple method to pattern conductive elastomers that work as electrodes or sensing probes in PDMS-based devices. With further development, this technology yields many potential applications in lab-on-a-chip systems

Compatibility of selected elastomers with plutonium glovebox environment

International Nuclear Information System (INIS)

Burns, R.

1994-06-01

This illustrative test was undertaken as a result of on-going failure of elastomer components in plutonium gloveboxes. These failures represent one of the major sources of required maintenance to keep gloveboxes operational. In particular, it was observed that the introduction of high specific activity Pu-238 into a glovebox, otherwise contaminated with Pu-239, resulted in an inordinate failure of elastomer components. Desiring to keep replacement of elastomer components to a minimum, a decision to explore a few possible alternative elastomer candidates was undertaken and reported upon herewith. Sample specimens of Neoprene, Urethane, Viton, and Hypalon elastomeric formulations were obtained from the Bacter Rubber Company. Strips of the elastomer specimens were placed in a plutonium glovebox and outside of a glovebox, and were observed for a period of three years. Of the four types of elastomers, only Hypalon remained completely viable

Evaluation of Tp-e interval and Tp-e/QT ratio in patients with non-dipper hypertension.

Science.gov (United States)

Demir, Mehmet; Uyan, Umut

2014-01-01

Non-dipper hypertension is associated with increased cardiovascular morbidity and mortality. Several studies have suggested that the interval from the peak to the end of the electrocardiographic T wave (Tp-e) may correspond to the transmural dispersion of repolarization and that increased Tp-e interval and Tp-e/QT ratio are associated with malignant ventricular arrhythmias. The aim of this study was to evaluate ventricular repolarization by using Tp-e interval and Tp-e/QT ratio in patients with non-dipper hypertension. This study included 80 hypertensive patients. Hypertensive patients were divided into two groups: 50 dipper patients (29 male, mean age 51.5 ± 8 years) and 30 non-dipper patients (17 male, mean age 50.6 ± 5.4 years). Tp-e interval and Tp-e/QT ratio were measured from the 12-lead electrocardiogram. These parameters were compared between groups. No statistically significant difference was found between two groups in terms of basic characteristics. In electrocardiographic parameters analysis, QT dispersion (QTd) and corrected QTd were significantly increased in non-dipper patients compared to the dippers (39.4 ± 11.5 versus 27.3 ± 7.5 ms and 37.5 ± 9.5 versus 29.2 ± 6.5 ms, p = 0.001 and p = 0.01, respectively). Tp-e interval and Tp-e/QT ratio were also significantly higher in non-dipper patients (97.5 ± 11.2 versus 84.2 ± 8.3 ms and 0.23 ± 0.02 versus 0.17 ± 0.02, all p value ratio are prolonged in patients with non-dipper hypertension.

Tp-e interval and Tp-e/QT ratio in patients with celiac disease.

Science.gov (United States)

Demirtaş, K; Yayla, Ç; Yüksel, M; Açar, B; Ünal, S; Ertem, A G; Kaplan, M; Akpinar, M Y; Kiliç, Z M Y; Kayaçetin, E

2017-11-01

Celiac disease is a chronic immune-mediated disease of the small intestine. It has been known that dilated cardiomyopathy and ischemic coronary artery disease have become more frequent in patients with celiac disease. The aim of the study was to assess Tp-e interval and Tp-e/QT ratio in patients with celiac disease. This study was conducted at a single center in collaboration with gastroenterology and cardiology clinics. Between January 2014 and June 2015, a total of 76 consecutive patients were enrolled (38 patients with celiac disease and 38 control subjects). Tp-e interval, Tp-e/QT and Tp-e/QTc ratio were measured from the 12-lead electrocardiogram. Tp-e interval (64.2±11.0 vs. 44.5±6.0; pceliac disease than control subjects. There was a significant positive correlation between Tp-e/QTc ratio and disease duration in patients with celiac disease (r=0.480, p=0.003) and also there was a significant positive correlation between Tp-e/QTc ratio and erythrocyte sedimentation rate (r=0.434, pceliac disease. Whether these changes increase the risk of ventricular arrhythmia deserve further studies. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Medicina Interna (SEMI). All rights reserved.

Processing a difficult urethane elastomer system

International Nuclear Information System (INIS)

Gillespie, T.J.

1977-01-01

A detailed study of an adiprene/butanediol/trimethylolpropane elastomer system and the associated production process was performed to assess the importance of various processing factors on the physical properties of the system. Results indicated that control of the curing cycle, material ratio, moisture in the curing agent and elastomer, mixing, and vacuum level was necessary. Sufficient control of the manual process could not be obtained to eliminate significant physical property variability. An automatic metering, mixing and dispensing machine was purchased for laboratory evaluation. After modification, including the addition of a high shear vacuum type mixer, and with close vacuum and temperature control, material property variability was still at an unacceptable level. A tracer agent was introduced into the curing agent system to assess the distribution of the curing agent in the elastomer. Machine evaluation using the tracer agent indicated that distribution of the curing agent in the elastomer was very poor is spite of the high shear mixing configuration. The addition of an oscillating motion to the mixing configuration. The addition of an oscillating motion to the mixing system significantly improved curing agent distribution and eliminated material property variability problems. 16 figures, 3 tables

Characterization of elastic-viscoplastic properties of an AS4/PEEK thermoplastic composite

Science.gov (United States)

Yoon, K. J.; Sun, C. T.

1991-01-01

The elastic-viscoplastic properties of an AS4/PEEK (APC-2) thermoplastic composite were characterized at 24 C (75 F) and 121 C (250 F) by using a one-parameter viscoplasticity model. To determine the strain-rate effects, uniaxial tension tests were performed on unidirectional off-axis coupon specimens with different monotonic strain rates. A modified Bodner and Partom's model was also used to describe the viscoplasticity of the thermoplastic composite. The experimental results showed that viscoplastic behavior can be characterized quite well using the one-parameter overstress viscoplasticity model.

Electrical breakdown phenomena of dielectric elastomers

DEFF Research Database (Denmark)

Mateiu, Ramona Valentina; Yu, Liyun; Skov, Anne Ladegaard

2017-01-01

Silicone elastomers have been heavily investigated as candidates for dielectric elastomers and are as such almost ideal candidates with their inherent softness and compliance but they suffer from low dielectric permittivity. This shortcoming has been sought optimized by many means during recent...... years. However, optimization with respect to the dielectric permittivity solely may lead to other problematic phenomena such as premature electrical breakdown. In this work, we investigate the electrical breakdown phenomena of various types of permittivity-enhanced silicone elastomers. Two types...... of silicone elastomers are investigated and different types of breakdown are discussed. Furthermore the use of voltage stabilizers in silicone-based dielectric elastomers is investigated and discussed....

An afterloading brachytherapy device utilizing thermoplastic material

International Nuclear Information System (INIS)

Kim, T.H.; Gerbi, J.B.; Deibel, F.C.; Khan, F.M.; Priest, J.R.

1989-01-01

An afterloading brachytherapy device for treatment of residual cancer in an enucleated orbit with two cesium-137 sources was designed using a thermoplastic material, Aquaplast. The device consists of a face-mask support held in place with elastic bands around the head and an acrylic afterloading applicator. The device is very easy to make, holds the sources firmly in place, allows full mobility of the patient, and gives excellent dose distribution to the target area. It was easily tolerated by a 7-year-old child during the 50 h of treatment. (author). 3 refs.; 4 figs

Microstructure of dimethylsiloxane based magnetic elastomers

International Nuclear Information System (INIS)

Balasoiu, M.; Craus, M.L.; Anitas, E.M.; Bica, I.; Plestil, J.; Kuklin, A.I.

2009-01-01

Dimethylsiloxane based elastomers filled with two types of magnetic particles (nano- and micro-sized) were investigated. It was obtained that doping with Fe 3 O 4 nanoparticles and applying of magnetic field during the polymerization process leads to a significant change of the local structure of elastomer. After filling the polymer with Fe 3 O 4 nanoparticles the magnetic elastomer presents a mass fractal structure. The mass fractal dimension is decreasing in the magnetic elastomer polymerized in magnetic field. For the elastomer filled with a large amount of Fe microparticles (75% particle concentration) a texture effect is detected; for the samples polymerized in magnetic field the texture effect is higher. Surface fractal property is obtained for all microparticle concentrations

Thermodynamics of coil-hyperbranched poly(styrene-b-acrylated epoxidized soybean oil) block copolymers

Science.gov (United States)

Lin, Fang-Yi; Hohmann, Austin; Hernández, Nacú; Cochran, Eric

Here we present the phase behavior of a new type of coil-hyperbranched diblock copolymer: poly(styrene- b-acrylated epoxidized soybean oil), or PS-PAESO. PS-PAESO is an example of a biorenewable thermoplastic elastomer (bio-TPE). To date, we have shown that bio-TPEs can be economical commercial substitutes for their petrochemically derived analogues--such as poly(styrene- b-butadiene- b-styrene) (SBS)--in a range of applications including pressure sensitive adhesives and bitumen modification. From a polymer physics perspective, PS-PAESO is an interesting material in that it couples a linear coil-like block with a highly branched block. Thus in contrast to the past five decades of studies on linear AB diblock copolymers, coil-hyperbranched block copolymers are relatively unknown to the community and can be expected to deviate substantially from the standard ``universal'' phase behavior in the AB systems. To explore these new materials, we have constructed a library of PS-PAESO materials spanning a range of molecular weight and composition values. The phase transition behavior and the morphology information will be interpreted by isochronal temperature scanning in dynamic shear rheology, small angle X-ray scattering and the corresponding transmission electron microscopy.

Self-Healing, High-Permittivity Silicone Dielectric Elastomer

DEFF Research Database (Denmark)

Madsen, Frederikke Bahrt; Yu, Liyun; Skov, Anne Ladegaard

2016-01-01

possesses high dielectric permittivity and consists of an interpenetrating polymer network of silicone elastomer and ionic silicone species that are cross-linked through proton exchange between amines and acids. The ionically cross-linked silicone provides self-healing properties after electrical breakdown...... or cuts made directly to the material due to the reassembly of the ionic bonds that are broken during damage. The dielectric elastomers presented in this paper pave the way to increased lifetimes and the ability of dielectric elastomers to survive millions of cycles in high-voltage conditions....

Thermoplastic starch materials prepared from rice starch

International Nuclear Information System (INIS)

Pontes, Barbara R.B.; Curvelo, Antonio A.S.

2009-01-01

Rice starch is a source still little studied for the preparation of thermoplastic materials. However, its characteristics, such as the presence of proteins, fats and fibers may turn into thermoplastics with a better performance. The present study intends the evaluation of the viability of making starch thermoplastic from rice starch and glycerol as plasticizer. The results of X-ray diffraction and scanning electronic microscopy demonstrate the thermoplastic acquisition. The increase of plasticizer content brings on more hydrophilic thermoplastics with less resistance to tension and elongation at break. (author)

Fire safety improvement of para-aramid fiber in thermoplastic polyurethane elastomer

International Nuclear Information System (INIS)

Chen, Xilei; Wang, Wenduo; Li, Shaoxiang; Jiao, Chuanmei

2017-01-01

Highlights: • Fire safety of para-aramid fiber on TPU has been investigated. • Para-aramid fiber has excellent flame retardant abilities and smoke suppression properties on TPU. • A new technique to improve the fire safety polymer is provided in this article. - Abstract: This article mainly studied fire safety effects of para-aramid fiber (AF) in thermoplastic polyurethane (TPU). The TPU/AF composites were prepared by molten blending method, and then the fire safety effects of all TPU composites were tested using cone calorimeter test (CCT), microscale combustion colorimeter test (MCC), smoke density test (SDT), and thermogravimetric/fourier transform infrared spectroscopy (TG-IR). The CCT test showed that AF could improve the fire safety of TPU. Remarkably, the peak value of heat release rate (pHRR) and the peak value of smoke production rate (pSPR) for the sample with 1.0 wt% content of AF were decreased by 52.0% and 40.5% compared with pure TPU, respectively. The MCC test showed that the HRR value of AF-2 decreased by 27.6% compared with pure TPU. TG test showed that AF promoted the char formation in the degradation process of TPU; as a result the residual carbon was increased. The TG-IR test revealed that AF had increased the thermal stability of TPU at the beginning and reduced the release of CO_2 with the decomposition going on. Through the analysis of the results of this experiment, it will make a great influence on the study of the para-aramid fiber in the aspect of fire safety of polymer.

Fire safety improvement of para-aramid fiber in thermoplastic polyurethane elastomer

Energy Technology Data Exchange (ETDEWEB)

Chen, Xilei; Wang, Wenduo; Li, Shaoxiang; Jiao, Chuanmei, E-mail: jiaochm@qust.edu.cn

2017-02-15

Highlights: • Fire safety of para-aramid fiber on TPU has been investigated. • Para-aramid fiber has excellent flame retardant abilities and smoke suppression properties on TPU. • A new technique to improve the fire safety polymer is provided in this article. - Abstract: This article mainly studied fire safety effects of para-aramid fiber (AF) in thermoplastic polyurethane (TPU). The TPU/AF composites were prepared by molten blending method, and then the fire safety effects of all TPU composites were tested using cone calorimeter test (CCT), microscale combustion colorimeter test (MCC), smoke density test (SDT), and thermogravimetric/fourier transform infrared spectroscopy (TG-IR). The CCT test showed that AF could improve the fire safety of TPU. Remarkably, the peak value of heat release rate (pHRR) and the peak value of smoke production rate (pSPR) for the sample with 1.0 wt% content of AF were decreased by 52.0% and 40.5% compared with pure TPU, respectively. The MCC test showed that the HRR value of AF-2 decreased by 27.6% compared with pure TPU. TG test showed that AF promoted the char formation in the degradation process of TPU; as a result the residual carbon was increased. The TG-IR test revealed that AF had increased the thermal stability of TPU at the beginning and reduced the release of CO{sub 2} with the decomposition going on. Through the analysis of the results of this experiment, it will make a great influence on the study of the para-aramid fiber in the aspect of fire safety of polymer.

Effect of phenol formaldehyde resin as vulcanizing agent on flow behavior of HDPE/PB blend

Directory of Open Access Journals (Sweden)

Moayad N. Khalaf

2014-07-01

Full Text Available Thermoplastic elastomer (TPE based on High density polyethylene (HDPE/polybutadiene (HDPE/PB = 70/30 parts blends containing 1, 3, 5, 7 and 10 wt.% of dimethylol phenolic resin as a vulcanizing agent in the presence of SnCl2 as catalyst was prepared. The dimethylol phenolic resin was prepared in our laboratory. The blends were compounded in mixer-60 attached to a Haake rheochord meter-90. The rheological properties were measured at temperatures 140, 160, 180 and 200 °C. The linearity of the flow curve appeared for 5% of the vulcanizing agent. The shear stress and shear viscosity have increased upon increasing the shear rate over a range of loading levels of vulcanizing agent of 1%, 3%, 5%, 7% and 10%. This may be attributed to the increased vulcanization between polyethylene and the rubber blend. The flow behavior index of the system shows a pseudo plastic nature behavior (since n < 1. The consistency index (K increased with the increase in the phenol formaldehyde resin content and the temperature. Hence, the increase in the value of the consistency index (K of the polymer melts refers to more viscous materials prepared. The activation energy for the TPE blends fluctuated indicating that there is phase separation; where each polymer behaved separately. This study showed that HDPE/PB blends are characterized with good rheological properties, which can be recommended to be processed with the injection molding technique.

Seismic performance evaluation of an MR elastomer-based smart base isolation system using real-time hybrid simulation

International Nuclear Information System (INIS)

Eem, S H; Jung, H J; Koo, J H

2013-01-01

Recently, magneto-rheological (MR) elastomer-based base isolation systems have been actively studied as alternative smart base isolation systems because MR elastomers are capable of adjusting their modulus or stiffness depending on the magnitude of the applied magnetic field. By taking advantage of the MR elastomers’ stiffness-tuning ability, MR elastomer-based smart base isolation systems strive to alleviate limitations of existing smart base isolation systems as well as passive-type base isolators. Until now, research on MR elastomer-based base isolation systems primarily focused on characterization, design, and numerical evaluations of MR elastomer-based isolators, as well as experimental tests with simple structure models. However, their applicability to large civil structures has not been properly studied yet because it is quite challenging to numerically emulate the complex behavior of MR elastomer-based isolators and to conduct experiments with large-size structures. To address these difficulties, this study employs the real-time hybrid simulation technique, which combines physical testing and computational modeling. The primary goal of the current hybrid simulation study is to evaluate seismic performances of an MR elastomer-based smart base isolation system, particularly its adaptability to distinctly different seismic excitations. In the hybrid simulation, a single-story building structure (non-physical, computational model) is coupled with a physical testing setup for a smart base isolation system with associated components (such as laminated MR elastomers and electromagnets) installed on a shaking table. A series of hybrid simulations is carried out under two seismic excitations having different dominant frequencies. The results show that the proposed smart base isolation system outperforms the passive base isolation system in reducing the responses of the structure for the excitations considered in this study. (paper)

Consolidation modelling for thermoplastic composites forming simulation

Science.gov (United States)

Xiong, H.; Rusanov, A.; Hamila, N.; Boisse, P.

2016-10-01

Pre-impregnated thermoplastic composites are widely used in the aerospace industry for their excellent mechanical properties, Thermoforming thermoplastic prepregs is a fast manufacturing process, the automotive industry has shown increasing interest in this manufacturing processes, in which the reconsolidation is an essential stage. The model of intimate contact is investigated as the consolidation model, compression experiments have been launched to identify the material parameters, several numerical tests show the influents of the temperature and pressure applied during processing. Finally, a new solid-shell prismatic element has been presented for the simulation of consolidation step in the thermoplastic composites forming process.

Role of Magnetorheological Fluids and Elastomers in Today’s World

Directory of Open Access Journals (Sweden)

Skalski Paweł

2017-12-01

Full Text Available This paper explains the role of magnetorheological fluids and elastomers in today’s world. A review of applications of magnetorheological fluids and elastomers in devices and machines is presented. Magnetorheological fluids and elastomers belong to the smart materials family. Properties of magnetorheological fluids and elastomers can be controlled by a magnetic field. Compared with magnetorheological fluids, magnetorheological elastomers overcome the problems accompanying applications of MR fluids, such as sedimentation, sealing issues and environmental contamination. Magnetorheological fluids and elastomers, due to their ability of dampening vibrations in the presence of a controlled magnetic field, have great potential present and future applications in transport. Magnetorheological fluids are used e.g. dampers, shock absorbers, clutches and brakes. Magnetorheological dampers and magnetorheological shock absorbers are applied e.g. in damping control, in the operation of buildings and bridges, as well as in damping of high-tension wires. In the automotive industry, new solutions involving magnetorheological elastomer are increasingly patented e.g. adaptive system of energy absorption, system of magnetically dissociable [hooks/detents/grips], an vibration reduction system of the car’s drive shaft. The application of magnetorheological elastomer in the aviation structure is presented as well.

Liquid-Embedded Elastomer Electronics

Science.gov (United States)

Kramer, Rebecca; Majidi, Carmel; Park, Yong-Lae; Paik, Jamie; Wood, Robert

2012-02-01

Hyperelastic sensors are fabricated by embedding a silicone rubber film with microchannels of conductive liquid. In the case of soft tactile sensors, pressing the surface of the elastomer will deform the cross-section of underlying channels and change their electrical resistance. Soft pressure sensors may be employed in a variety of applications. For example, a network of pressure sensors can serve as artificial skin by yielding detailed information about contact pressures. This concept was demonstrated in a hyperelastic keypad, where perpendicular conductive channels form a quasi-planar network within an elastomeric matrix that registers the location, intensity and duration of applied pressure. In a second demonstration, soft curvature sensors were used for joint angle proprioception. Because the sensors are soft and stretchable, they conform to the host without interfering with the natural mechanics of motion. This marked the first use of liquid-embedded elastomer electronics to monitor human or robotic motion. Finally, liquid-embedded elastomers may be implemented as conductors in applications that call for flexible or stretchable circuitry, such as robotic origami.

Effects of Carbon Black Type on Breathable Butyl Rubber Membranes

National Research Council Canada - National Science Library

Threepopnatkul, P; Murphy, D; Mead, J; Zukas, W

2006-01-01

...) protective garments. The advantages of an electrospun crosslinked elastomer system, when compared to similarly prepared thermoplastics, are increased flexibility, durability, and chemical resistance...

Effects of tritium in elastomers

International Nuclear Information System (INIS)

Zapp, P.E.

1982-01-01

Elastomers are used as flange gaskets in the piping system of the Savannah River Plant tritium facilities. A number of elastomers is being examined to identify those compounds more radiation-resistant than the currently specified Buna-N rubber and to study the mechanism of tritium radiation damage. Radiation resistance is evaluated by compression set tests on specimens exposed to about 1 atm tritium for several months. Initial results show that ethylene-propylene rubber and three fluoroelastomers are superior to Buna-N. Off-gassing measurements and autoradiography show that retained surface absorption of tritium varies by more than an order of magnitude among the different elastomer compounds. Therefore, tritium solubility and/or exchange may have a role in addition to that of chemical structure in the damage process. Ongoing studies of the mechanism of radiation damage include: (1) tritium absorption kinetics, (2) mass spectroscopy of radiolytic products, and (3) infrared spectroscopy

Fluorinated Amphiphilic Polymers and Their Blends for Fouling-Release Applications: The Benefits of a Triblock Copolymer Surface

KAUST Repository

Sundaram, Harihara S.

2011-09-28

Surface active triblock copolymers (SABC) with mixed polyethylene glycol (PEG) and two different semifluorinated alcohol side chains, one longer than the other, were blended with a soft thermoplastic elastomer (TPE), polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS). The surface composition of these blends was probed by X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The surface reconstruction of the coatings in water was monitored qualitatively by dynamic water contact angles in air as well as air bubble contact angle measurements in water. By blending the SABC with SEBS, we minimize the amount of the SABC used while achieving a surface that is not greatly different in composition from the pure SABC. The 15 wt % blends of the SABC with long fluoroalkyl side chains showed a composition close to that of the pure SABC while the SABC with shorter perfluoroakyl side chains did not. These differences in surface composition were reflected in the fouling-release performance of the blends for the algae, Ulva and Navicula. © 2011 American Chemical Society.

Textile impregnation with thermoplastic resin - models and application

NARCIS (Netherlands)

Loendersloot, Richard; Grouve, Wouter Johannes Bernardus; Lamers, E.A.D.; Wijskamp, Sebastiaan; Kelly, P.A.; Bickerton, S.; Lescher, P.; Govignon, Q.

2012-01-01

One of the key issues of the development of cost-effective thermoplastic composites for the aerospace industry is the process quality control. A complete, void free impregnation of the textile reinforcement by the thermoplastic resin is an important measure of the quality of composites. The

Material Evaluation of an Elastomer, Epoxy and Lightweight Concrete Rail Attachment System for Direct Fixation Light Rail Applications

Science.gov (United States)

Swarner, Benjamin R.

Sound Transit plans to extend its current light rail system, which runs along the I-5 corridor in Seattle, Washington, across the I-90 Homer Hadley floating bridge as part of a project to connect the major city centers in the region. But, no light rail has ever crossed a floating bridge due to several unique engineering challenges. One of these challenges is attaching the rails to the existing bridge deck without drilling into the bridge pontoons. This research program was developed to test and analyze a direct fixation method that uses lightweight concrete plinths and an elastomer-epoxy system to attach the rails to the bridge deck. The elastomer used was a two-part, pourable elastomer with cork particles intermixed to alter the mechanical properties of the material. A lightweight concrete mixture was analyzed for use in the plinths, and system tests investigated the system response under tensile, compressive and shear loading. The shear response of the system was examined further under varying loading conditions including different surface preparations, elastomer thicknesses, strain-rates and after freeze-thaw conditioning. Experimental data was examined for trends based on these parameters to best characterize the system, and the elastomer was evaluated in the context of modern elastomer research.

Processing and characterization of recycled poly(ethylene terephthalate) blends with chain extenders, thermoplastic elastomer, and/or poly(butylene adipate-co-terephthalate)

Science.gov (United States)

Yottha Srithep; Alireza Javadi; Srikanth Pilla; Lih-Sheng Turng; Shaoqin Gong; Craig Clemons; Jun Peng

2011-01-01

Poly(ethylene terephthalate) (PET) resin is one of the most widely used thermoplastics, especially in packaging. Because thermal and hydrolytic degradations, recycled PET (RPET) exhibits poor mechanical properties and lacks moldability. The effects of adding elastomeric modifiers, chain extenders (CE), and poly(butylenes adipate-co-terephthalate), PBAT, as a toughener...

Biodegradable xylitol-based elastomers: In vivo behavior and biocompatibility

NARCIS (Netherlands)

J.P. Bruggeman (Joost); C.J. Bettinger (Christopher); R.S. Langer (Robert)

2010-01-01

textabstractBiodegradable elastomers based on polycondensation reactions of xylitol with sebacic acid, referred to as poly(xylitol sebacate) (PXS) elastomers have recently been developed. We describe the in vivo behavior of PXS elastomers. Four PXS elastomers were synthesized, characterized, and

Pressure-induced emission band separation of the hybridized local and charge transfer excited state in a TPE-based crystal.

Science.gov (United States)

Liu, Xuedan; Li, Aisen; Xu, Weiqing; Ma, Zhiyong; Jia, Xinru

2018-05-08

We herein report a newly synthesized simple molecule, named TPE[double bond, length as m-dash]C4, with twisted D-A structure. TPE[double bond, length as m-dash]C4 showed two intrinsic emission bands ascribed to the locally excited (LE) state and the intramolecular charge transfer (ICT) state, respectively. In the crystal state, the LE emission band is usually observed. However, by applying hydrostatic pressure to the powder sample and the single crystal sample of TPE[double bond, length as m-dash]C4, dual-fluorescence (445 nm and 532 nm) was emerged under high pressure, owing to the pressure-induced emission band separation of the hybridized local and charge transfer excited state (HLCT). It is found that the emission of TPE[double bond, length as m-dash]C4 is generally determined by the ratio of the LE state to the ICT state. The ICT emission band is much more sensitive to the external pressure than the LE emission band. The HLCT state leads to a sample with different responsiveness to grinding and hydrostatic pressure. This study is of significance in the molecular design of such D-A type molecules and in the control of photoluminescence features by molecular structure. Such results are expected to pave a new way to further understand the relationship between the D-A molecular structure and stimuli-responsive properties.

Polyurethane elastomer as a matrix material for short carbon fiber reinforced thermoplastic composites

Directory of Open Access Journals (Sweden)

Ümit Tayfun

2017-09-01

Full Text Available Short carbon fibers (CF with different surface sized (epoxy (EP and polyurethane (PU were used as reinforcing agent in thermoplastic polyurethane (TPU based composites. Composites containing 5, 10, 15, and 20 weight % sized and desized CFs were prepared by using melt-mixing method. The surface characteristics of CFs were examined by energy dispersive X-ray spectroscopy (EDX and Fourier transform infrared spectroscopy (FTIR. Tensile testing, shore hardness test, dynamic mechanical analysis (DMA and melt flow index (MFI test were performed for determining final composite properties. The dispersion of CFs in TPU matrix was examined by scanning electron microscopy (SEM. Tensile strength, Youngs’ modulus and Shore hardness of TPU were enhanced by the addition of sized CFs. About two-fold improvement for tensile strength and ten-fold improvement for Youngs’ modulus were observed with the incorporation of 20 wt% EP-CF and PU-CF in TPU. The storage modulus of PU-CF containing composites was higher than those of TPU and other composites. No remarkable change was observed in MFI value of TPU after CF loadings. Processing conditions in this work was suitable for composite production. Sized CFs exhibited better dispersion with regard to desized CF due to the stronger adhesion of TPU matrix to fiber surface.

Effects of mechanical properties of thermoplastic materials on the initial force of thermoplastic appliances.

Science.gov (United States)

Kohda, Naohisa; Iijima, Masahiro; Muguruma, Takeshi; Brantley, William A; Ahluwalia, Karamdeep S; Mizoguchi, Itaru

2013-05-01

To measure the forces delivered by thermoplastic appliances made from three materials and investigate effects of mechanical properties, material thickness, and amount of activation on orthodontic forces. Three thermoplastic materials, Duran (Scheu Dental), Erkodur (Erkodent Erich Kopp GmbH), and Hardcast (Scheu Dental), with two different thicknesses were selected. Values of elastic modulus and hardness were obtained from nanoindentation measurements at 28°C. A custom-fabricated system with a force sensor was employed to obtain measurements of in vitro force delivered by the thermoplastic appliances for 0.5-mm and 1.0-mm activation for bodily tooth movement. Experimental results were subjected to several statistical analyses. Hardcast had significantly lower elastic modulus and hardness than Duran and Erkodur, whose properties were not significantly different. Appliances fabricated from thicker material (0.75 mm or 0.8 mm) always produced significantly greater force than those fabricated from thinner material (0.4 mm or 0.5 mm). Appliances with 1.0-mm activation produced significantly lower force than those with 0.5-mm activation, except for 0.4-mm thick Hardcast appliances. A strong correlation was found between mechanical properties of the thermoplastic materials and force produced by the appliances. Orthodontic forces delivered by thermoplastic appliances depend on the material, thickness, and amount of activation. Mechanical properties of the polymers obtained by nanoindentation testing are predictive of force delivery by these appliances.

Power supply of ETL-TPE 2

International Nuclear Information System (INIS)

Takeda, Syohei; Sato, Yasuhiro; Kiyama, Satoru; Ikeda, Nagayasu

1986-01-01

The ETL-TPE2 experiment is planned to investigate a behavior of high beta plasma with high temperature. A system design of power supply to generate and to confine the plasma is described. Essential features of the design are the following; 1) To obtain a dense plasma with high temperature, two capacitor banks with opposite polarities of 80 kV charging voltage are provided in tandem feed for the toroidal fast field. 2) A high current pulse with long duration is supplied by a power crowbar system and realizes the investigation of the plasma confinement for a longer pulsed magnetic field. A power supply system of the power crowbar is connected with a main circuit in series through a current transformer. The circuit system is operated at high efficiency and high reliability. 3) In the vertical and compensating field circuits, each rise time and peak value of currents can be controlled over a wide range of pre-set programmings corresponding to an experimental condition. 4) A small resistance is connected with a crowbar circuit in a compression pre-heat field circuit. The circuit can be crowbarred at an arbitrary phase. This operation and the effect of additional resistance are favourable to maintain an effective plasma heating and to improve the plasma confinement. (author)

Perceptual learning of basic visual features remains task specific with Training-Plus-Exposure (TPE) training.

Science.gov (United States)

Cong, Lin-Juan; Wang, Ru-Jie; Yu, Cong; Zhang, Jun-Yun

2016-01-01

Visual perceptual learning is known to be specific to the trained retinal location, feature, and task. However, location and feature specificity can be eliminated by double-training or TPE training protocols, in which observers receive additional exposure to the transfer location or feature dimension via an irrelevant task besides the primary learning task Here we tested whether these new training protocols could even make learning transfer across different tasks involving discrimination of basic visual features (e.g., orientation and contrast). Observers practiced a near-threshold orientation (or contrast) discrimination task. Following a TPE training protocol, they also received exposure to the transfer task via performing suprathreshold contrast (or orientation) discrimination in alternating blocks of trials in the same sessions. The results showed no evidence for significant learning transfer to the untrained near-threshold contrast (or orientation) discrimination task after discounting the pretest effects and the suprathreshold practice effects. These results thus do not support a hypothetical task-independent component in perceptual learning of basic visual features. They also set the boundary of the new training protocols in their capability to enable learning transfer.

Dielectric Elastomers for Fluidic and Biomedical Applications

Science.gov (United States)

McCoul, David James

Dielectric elastomers have demonstrated tremendous potential as high-strain electromechanical transducers for a myriad of novel applications across all engineering disciplines. Because their soft, viscoelastic mechanical properties are similar to those of living tissues, dielectric elastomers have garnered a strong foothold in a plethora of biomedical and biomimetic applications. Dielectric elastomers consist of a sheet of stretched rubber, or elastomer, coated on both sides with compliant electrode materials; application of a voltage generates an electrostatic pressure that deforms the elastomer. They can function as soft generators, sensors, or actuators, and this last function is the focus of this dissertation. Many design configurations are possible, such as stacks, minimum energy structures, interpenetrating polymer networks, shape memory dielectric elastomers, and others; dielectric elastomers are already being applied to many fields of biomedicine. The first part of the original research presented in this dissertation details a PDMS microfluidic system paired with a dielectric elastomer stack actuator of anisotropically prestrained VHB(TM) 4910 (3M(TM)) and single-walled carbon nanotubes. These electroactive microfluidic devices demonstrated active increases in microchannel width when 3 and 4 kV were applied. Fluorescence microscopy also indicated an accompanying increase in channel depth with actuation. The cross-sectional area strains at 3 and 4 kV were approximately 2.9% and 7.4%, respectively. The device was then interfaced with a syringe pump, and the pressure was measured upstream. Linear pressure-flow plots were developed, which showed decreasing fluidic resistance with actuation, from 0.192 psi/(microL/min) at 0 kV, to 0.160 and 0.157 psi/(microL/min) at 3 and 4 kV, respectively. This corresponds to an ~18% drop in fluidic resistance at 4 kV. Active de-clogging was tested in situ with the device by introducing ~50 microm diameter PDMS microbeads and

Effect of chemical disinfectants and accelerated aging on maxillofacial silicone elastomers: An In vitro Study

Directory of Open Access Journals (Sweden)

Anna Serene Babu

2018-01-01

Full Text Available Context: Maxillofacial prostheses need frequent refabrication due to degradation of color and deterioration of physical properties of the elastomer. Aims: This study attempted to evaluate the change in color stability, Shore A hardness, and surface roughness of two maxillofacial silicones, A-2186 and Cosmesil M511, when submitted to chemical disinfection and accelerated aging. Settings and Design: This was a comparative in vitro study. Subjects and Methods: The materials included two silicone elastomers – A-2186 and Cosmesil M511 (Factor II Incorporated – functional intrinsic red pigment and three disinfectants – Fittydent tablet, chlorhexidine gluconate 4%, and neutral soap. The specimens in each group of elastomer were evaluated initially for color, hardness, and surface roughness, which were further divided into subgroups and subjected to disinfection and accelerated aging. The evaluation of color was performed with the help of an ultraviolet reflectance spectrophotometer. Shore A hardness was evaluated using a durometer and surface roughness, with a digital roughness tester followed by scanning electron microscopy analysis. Statistical Analysis Used: Analysis of variance and Tukey's multiple comparison test were used for statistical analysis. Results: Accelerated aging caused a significant decrease in color, increase in Shore A hardness, and variation in surface roughness in both silicone elastomer groups. Chemical disinfection presented significant changes in color and surface roughness whereas no significant effect on Shore hardness, irrespective of the disinfectant used. Conclusions: The maxillofacial silicone elastomers presented deterioration in color, hardening, and significant variations in surface roughness when subjected to chemical disinfection and accelerated aging, which provides a valid baseline for future research.

Disclosed dielectric and electromechanical properties of hydrogenated nitrile–butadiene dielectric elastomer

International Nuclear Information System (INIS)

Yang, Dan; Tian, Ming; Dong, Yingchao; Liu, Haoliang; Yu, Yingchun; Zhang, Liqun

2012-01-01

This paper presents a comprehensive study of the effects of acrylonitrile content, crosslink density and plasticization on the dielectric and electromechanical performances of hydrogenated nitrile–butadiene dielectric elastomer. It was found that by increasing the acrylonitrile content of hydrogenated nitrile–butadiene dielectric elastomer, the dielectric constant will be improved accompanied with a sharp decrease of electrical breakdown strength leading to a small actuated strain. At a fixed electric field, a high crosslink density increased the elastic modulus of dielectric elastomer, but it also enhanced the electrical breakdown strength leading to a high actuated strain. Adding a plasticizer into the dielectric elastomer decreased the dielectric constant and electrical breakdown strength slightly, but reduced the elastic modulus sharply, which was beneficial for obtaining a large strain at low electric field from the dielectric elastomer. The largest actuated strain of 22% at an electric field of 30 kV mm −1 without any prestrain was obtained. Moreover, the hydrogenated nitrile–butadiene dielectric actuator showed good history dependence. This proposed material has great potential to be an excellent dielectric elastomer. (paper)

Dielectric elastomer actuators used for pneumatic valve technology

International Nuclear Information System (INIS)

Giousouf, Metin; Kovacs, Gabor

2013-01-01

Dielectric elastomer actuators have been investigated for applications in the field of pneumatic automation technology. We have developed different valve designs with stacked dielectric elastomer actuators and with integrated high voltage converters. The actuators were made using VHB-4910 material and a stacker machine for automated fabrication of the cylindrical actuators. Typical characteristics of pneumatic valves such as flow rate, power consumption and dynamic behaviour are presented. For valve construction the force and stroke parameters of the dielectric elastomer actuator have been measured. Further, benefits for valve applications using dielectric elastomers are shown as well as their potential operational area. Finally, challenges are discussed that are relevant for the use of elastomer actuators in valves for industrial applications. (paper)

Flexible and stretchable electrodes for dielectric elastomer actuators

Science.gov (United States)

Rosset, Samuel; Shea, Herbert R.

2013-02-01

Dielectric elastomer actuators (DEAs) are flexible lightweight actuators that can generate strains of over 100 %. They are used in applications ranging from haptic feedback (mm-sized devices), to cm-scale soft robots, to meter-long blimps. DEAs consist of an electrode-elastomer-electrode stack, placed on a frame. Applying a voltage between the electrodes electrostatically compresses the elastomer, which deforms in-plane or out-of plane depending on design. Since the electrodes are bonded to the elastomer, they must reliably sustain repeated very large deformations while remaining conductive, and without significantly adding to the stiffness of the soft elastomer. The electrodes are required for electrostatic actuation, but also enable resistive and capacitive sensing of the strain, leading to self-sensing actuators. This review compares the different technologies used to make compliant electrodes for DEAs in terms of: impact on DEA device performance (speed, efficiency, maximum strain), manufacturability, miniaturization, the integration of self-sensing and self-switching, and compatibility with low-voltage operation. While graphite and carbon black have been the most widely used technique in research environments, alternative methods are emerging which combine compliance, conduction at over 100 % strain with better conductivity and/or ease of patternability, including microfabrication-based approaches for compliant metal thin-films, metal-polymer nano-composites, nanoparticle implantation, and reel-to-reel production of μm-scale patterned thin films on elastomers. Such electrodes are key to miniaturization, low-voltage operation, and widespread commercialization of DEAs.

Tool-ply friction in thermoplastic composite forming (CD-rom)

NARCIS (Netherlands)

ten Thije, R.H.W.; Akkerman, Remko; van der Meer, L.; Ubbink, M.P.; Boisse, P.

2008-01-01

Friction is an important phenomenon that can dominate the resulting product geometry of thermoplastic composites upon forming. A model was developed that predicts the friction between a thermoplastic laminate and a rigid tool. The mesoscopic model, based on the Reynolds’ equation for thin film

Active vibration isolation platform on base of magnetorheological elastomers

Energy Technology Data Exchange (ETDEWEB)

Mikhailov, Valery P., E-mail: mikhailov@bmstu.ru; Bazinenkov, Alexey M.

2017-06-01

The article describes the active vibration isolation platform on base of magnetorheological (MR) elastomers. An active damper based on the MR elastomers can be used as an actuator of micro- or nanopositioning for a vibroinsulated object. The MR elastomers give such advantages for active control of vibration as large range of displacements (up to 1 mm), more efficient absorption of the vibration energy, possibility of active control of amplitude-frequency characteristics and positioning with millisecond response speed and nanometer running accuracy. The article presents the results of experimental studies of the most important active damper parameters. Those are starting current, transient time for stepping, transmission coefficient of the vibration displacement amplitude.

Suppression of electromechanical instability in fiber-reinforced dielectric elastomers

Directory of Open Access Journals (Sweden)

Rui Xiao

2016-03-01

Full Text Available The electromechanical instability of dielectric elastomers has been a major challenge for the application of this class of active materials. In this work, we demonstrate that dielectric elastomers filled with soft fiber can suppress the electromechanical instability and achieve large deformation. Specifically, we developed a constitutive model to describe the dielectric and mechanical behaviors of fiber-reinforced elastomers. The model was applied to study the influence of stiffness, nonlinearity properties and the distribution of fiber on the instability of dielectric membrane under an electric field. The results show that there exists an optimal fiber distribution condition to achieve the maximum deformation before failure.

Cryomilling of Thermoplastic Powder for Prepreg Applications

Science.gov (United States)

2013-09-01

Cryomilling of Thermoplastic Powder for Prepreg Applications by Brian Parquette, Anit Giri, Daniel J. O’Brien, Sarah Brennan, Kyu Cho, and...MD 21005-5066 ARL-TR-6591 September 2013 Cryomilling of Thermoplastic Powder for Prepreg Applications Brian Parquette and Sarah Brennan...COVERED (From - To) 1 March 2012–30 May 2013 4. TITLE AND SUBTITLE Cryomilling of Thermoplastic Powder for Prepreg Applications 5a. CONTRACT

STIR: Redox-Switchable Olefin Polymerization Catalysis: Electronically Tunable Ligands for Controlled Polymer Synthesis

Science.gov (United States)

2013-03-28

production of polyethylene (PE) and polypropylene (PP) topped 53 billion pounds in 2011.1 This extreme demand has ensured that olefin polymerization...is an ideal starting monomer as it is a liquid at room temperature facilitating rapid screening and data collection without the need for cumbersome...elastomers, binders, thermoplastic elastomers, rheology modifiers, permeation selective membranes, and high strength, light-weight structural materials

Applications of pressure-sensitive dielectric elastomer sensors

Science.gov (United States)

Böse, Holger; Ocak, Deniz; Ehrlich, Johannes

2016-04-01

Dielectric elastomer sensors for the measurement of compression loads with high sensitivity are described. The basic design of the sensors exhibits two profiled surfaces between which an elastomer film is confined. All components of the sensor were prepared with silicone whose stiffness can be varied in a wide range. Depending on details of the sensor design, various effects contribute to the enhancement of the capacitance. The intermediate elastomer film is stretched upon compression and electrode layers on the elastomer profiles and in the elastomer film approach each other. Different designs of the pressure sensor give rise to very different sensor characteristics in terms of the dependence of electric capacitance on compression force. Due to their inherent flexibility, the pressure sensors can be used on compliant substrates such as seats or beds or on the human body. This gives rise to numerous possible applications. The contribution describes also some examples of possible sensor applications. A glove was equipped with various sensors positioned at the finger tips. When grabbing an object with the glove, the sensors can detect the gripping forces of the individual fingers with high sensitivity. In a demonstrator of the glove equipped with seven sensors, the capacitances representing the gripping forces are recorded on a display. In another application example, a lower limb prosthesis was equipped with a pressure sensor to detect the load on the remaining part of the leg and the load is displayed in terms of the measured capacitance. The benefit of such sensors is to detect an eventual overload in order to prevent possible pressure sores. A third example introduces a seat load sensor system based on four extended pressure sensor mats. The sensor system detects the load distribution of a person on the seat. The examples emphasize the high performance of the new pressure sensor technology.

Manufacturing a 9-Meter Thermoplastic Composite Wind Turbine Blade: Preprint

Energy Technology Data Exchange (ETDEWEB)

Murray, Robynne [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Snowberg, David R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Berry, Derek S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beach, Ryan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rooney, Samantha A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Swan, Dana [Arkema Inc.

2017-12-06

Currently, wind turbine blades are manufactured from a combination of glass and/or carbon fiber composite materials with a thermoset resin such as epoxy, which requires energy-intensive and expensive heating processes to cure. Newly developed in-situ polymerizing thermoplastic resin systems for composite wind turbine blades polymerize at room temperature, eliminating the heating process and significantly reducing the blade manufacturing cycle time and embodied energy, which in turn reduces costs. Thermoplastic materials can also be thermally welded, eliminating the need for adhesive bonds between blade components and increasing the overall strength and reliability of the blades. As well, thermoplastic materials enable end-of-life blade recycling by reheating and decomposing the materials, which is a limitation of existing blade technology. This paper presents a manufacturing demonstration for a 9-m-long thermoplastic composite wind turbine blade. This blade was constructed in the Composites Manufacturing Education and Technology facility at the National Wind Technology Center at the National Renewable Energy Laboratory (NREL) using a vacuum-assisted resin transfer molding process. Johns Manville fiberglass and an Arkema thermoplastic resin called Elium were used. Additional materials included Armacell-recycled polyethylene terephthalate foam from Creative Foam and low-cost carbon- fiber pultruded spar caps (manufactured in collaboration with NREL, Oak Ridge National Laboratory, Huntsman, Strongwell, and Chomarat). This paper highlights the development of the thermoplastic resin formulations, including an additive designed to control the peak exothermic temperatures. Infusion and cure times of less than 3 hours are also demonstrated, highlighting the efficiency and energy savings associated with manufacturing thermoplastic composite blades.

Thermoplastic Composite Wind Turbine Blades : An Integrated Design Approach

NARCIS (Netherlands)

Joncas, S.

2010-01-01

This thesis proposes a new structural design concept for future large wind turbine blades based on fully recyclable thermoplastic composites (TPC). With respect to material properties, cost and processing, reactively processed anionic polyamide-6 (APA-6) has been identified as the most promising

TPE upgrade for enhancing operational safety and improving in-vessel tritium inventory assessment in fusion nuclear environment

Energy Technology Data Exchange (ETDEWEB)

Shimada, M., E-mail: Masashi.Shimada@inl.gov [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Taylor, C.N.; Moore-McAteer, L.; Pawelko, R.J. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Kolasinski, R.D.; Buchenauer, D.A. [Sandia National Laboratories, Hydrogen and Materials Science Department, Livermore, CA 94550 (United States); Cadwallader, L.C.; Merrill, B.J. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

2016-11-01

The Tritium Plasma Experiment (TPE) is a unique high-flux linear plasma device that can handle beryllium, tritium, and neutron-irradiated plasma facing materials, and is the only existing device dedicated to evaluate in-vessel tritium inventory in the nuclear environment for fusion safety. The electrical upgrade were recently carried out to enhance operational safety and to improve plasma performance. New DC power supplies and a new control center enable remote plasma operations from outside of the contamination area for tritium, minimizing the possible exposure risk with tritium and beryllium and eliminating heat stress issue. In November 2015, the TPE successfully achieved first deuterium plasma via remote operation after a significant three-year upgrade. Simple linear scaling estimate showed that the TPE is expected to achieve Γ{sub i}{sup max} of >1.0 × 10{sup 23} m{sup −2} s{sup −1} and q{sub heat} of >1 MW m{sup −2} with new power supplies. This upgrade not only improves operational safety of the worker, but also enhances plasma performance to better simulate extreme plasma-material conditions expected in ITER, FNSF, and DEMO for improving in-vessel tritium inventory assessment in fusion nuclear environment.

Patterning nonisometric origami in nematic elastomer sheets

Science.gov (United States)

Plucinsky, Paul; Kowalski, Benjamin A.; White, Timothy J.; Bhattacharya, Kaushik

Nematic elastomers dramatically change their shape in response to diverse stimuli including light and heat. In this paper, we provide a systematic framework for the design of complex three dimensional shapes through the actuation of heterogeneously patterned nematic elastomer sheets. These sheets are composed of \\textit{nonisometric origami} building blocks which, when appropriately linked together, can actuate into a diverse array of three dimensional faceted shapes. We demonstrate both theoretically and experimentally that: 1) the nonisometric origami building blocks actuate in the predicted manner, 2) the integration of multiple building blocks leads to complex multi-stable, yet predictable, shapes, 3) we can bias the actuation experimentally to obtain a desired complex shape amongst the multi-stable shapes. We then show that this experimentally realized functionality enables a rich possible design landscape for actuation using nematic elastomers. We highlight this landscape through theoretical examples, which utilize large arrays of these building blocks to realize a desired three dimensional origami shape. In combination, these results amount to an engineering design principle, which we hope will provide a template for the application of nematic elastomers to emerging technologies.

Metal and elastomer seal tests for accelerator applications

International Nuclear Information System (INIS)

Welch, K.M.; McIntyre, G.T.; Tuozzolo, J.E.; Skelton, R.; Pate, D.J.; Gill, S.M.

1989-01-01

The vacuum system of the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory has more than a thousand metal vacuum seals. Also, numerous elastomer seals are used throughout the AGS to seal large beam component chambers. An accelerator upgrade program is being implemented to reduce the AGS operating pressure by x100 and improve the reliability of the vacuum system. This paper describes work in progress on metal and elastomer vacuum seals to help meet those two objectives. Tests are reported on the sealing properties of a variety of metal seals used on different sealing surfaces. Results are also given on reversible sorption properties of certain elastomers. 16 refs., 6 figs., 4 tabs

Wood thermoplastic composites

Science.gov (United States)

Daniel F. Caulfield; Craig Clemons; Roger M. Rowell

2010-01-01

The wood industry can expand into new sustainable markets with the formation of a new class of composites with the marriage of the wood industry and the plastics industry. The wood component, usually a flour or fiber, is combined with a thermoplastic to form an extrudable, injectable or thermoformable composite that can be used in many non-structural applications....

Poly (ricinoleic acid) based novel thermosetting elastomer.

Science.gov (United States)

Ebata, Hiroki; Yasuda, Mayumi; Toshima, Kazunobu; Matsumura, Shuichi

2008-01-01

A novel bio-based thermosetting elastomer was prepared by the lipase-catalyzed polymerization of methyl ricinoleate with subsequent vulcanization. Some mechanical properties of the cured carbon black-filled polyricinoleate compounds were evaluated as a thermosetting elastomer. It was found that the carbon black-filled polyricinoleate compounds were readily cured by sulfur curatives to produce a thermosetting elastomer that formed a rubber-like sheet with a smooth and non-sticky surface. The curing behaviors and mechanical properties were dependent on both the molecular weight of the polyricinoleate and the amount of the sulfur curatives. Cured compounds consisting of polyricinoleate with a molecular weight of 100,800 showed good mechanical properties, such as a hardness of 48 A based on the durometer A measurements, a tensile strength at break of 6.91 MPa and an elongation at break of 350%.

Magnetoactive elastomer as an element of a magnetic retina fixator

Science.gov (United States)

Makarova, L. A.; Nadzharyan, T. A.; Alekhina, Yu A.; Stepanov, G. V.; Kazimirova, E. G.; Perov, N. S.; Kramarenko, E. Yu

2017-09-01

We explore the possibility of creating an effective retinal fixator on the basis of magnetoactive elastomers (MAEs) and systems of permanent magnets. MAEs consist of silicone elastomer matrix with embedded magnetic iron microparticles. We study theoretically and experimentally magnetic forces acting between MAE samples and permanent magnets in various configurations. The theoretical model is based around classical magnetostatics and Maxwell equations with different parameters accounting for peculiarities of the material and the setup. Approximation of the experimentally measured magnetization curves for MAE samples was used to find input parameters for the theoretical model. To test the model, we conducted a series of experimental measurements of magnetic forces accompanied by model predictions for the system of one cylindrical magnet and a cuboid MAE sample. Calculated dependences of the average pressure arising from magnetic interactions on the distance between the closest faces of MAE samples and a permanent magnet are in a good agreement with the experimental data. The proof on concept for smaller magnetic systems required for eye surgery includes data for 10 magnets configuration and a thin MAE band. This research demonstrates high prospects of using MAE as an element of a magnetic fixator for treatment of complicated retinal detachments.

Toughening elastomers with sacrificial bonds and watching them break

NARCIS (Netherlands)

Ducrot, E.; Chen, Y.; Bulters, M.J.H.; Sijbesma, R.P.; Creton, C.

2014-01-01

Elastomers are widely used because of their large-strain reversible deformability. Most unfilled elastomers suffer from a poor mechanical strength, which limits their use. Using sacrificial bonds, we show how brittle, unfilled elastomers can be strongly reinforced in stiffness and toughness (up to 4

The Electrical Breakdown of Thin Dielectric Elastomers

DEFF Research Database (Denmark)

Zakaria, Shamsul Bin; Morshuis, Peter H. F.; Yahia, Benslimane Mohamed

2014-01-01

Dielectric elastomers are being developed for use in actuators, sensors and generators to be used in various applications, such as artificial eye lids, pressure sensors and human motion energy generators. In order to obtain maximum efficiency, the devices are operated at high electrical fields....... This increases the likelihood for electrical breakdown significantly. Hence, for many applications the performance of the dielectric elastomers is limited by this risk of failure, which is triggered by several factors. Amongst others thermal effects may strongly influence the electrical breakdown strength....... In this study, we model the electrothermal breakdown in thin PDMS based dielectric elastomers in order to evaluate the thermal mechanisms behind the electrical failures. The objective is to predict the operation range of PDMS based dielectric elastomers with respect to the temperature at given electric field...

Hencky's model for elastomer forming process

Science.gov (United States)

Oleinikov, A. A.; Oleinikov, A. I.

2016-08-01

In the numerical simulation of elastomer forming process, Henckys isotropic hyperelastic material model can guarantee relatively accurate prediction of strain range in terms of large deformations. It is shown, that this material model prolongate Hooke's law from the area of infinitesimal strains to the area of moderate ones. New representation of the fourth-order elasticity tensor for Hencky's hyperelastic isotropic material is obtained, it possesses both minor symmetries, and the major symmetry. Constitutive relations of considered model is implemented into MSC.Marc code. By calculating and fitting curves, the polyurethane elastomer material constants are selected. Simulation of equipment for elastomer sheet forming are considered.

Development of thermoplastic elastomers based on maleated ethylene propylene rubber (m-EPM and polypropylene (PP by dynamic vulcanization

Directory of Open Access Journals (Sweden)

2007-08-01

Full Text Available Dicumyl peroxide (DCP-cured thermoplastic vulcanizates (TPVs based on blends of maleated ethylene propylene rubber (m-EPM and polypropylene (PP using maleated-PP as a compatibilizer have been developed. Physical properties of these TPVs change significantly with concentrations of DCP and rubber/plastic blend ratios. Important correlations were obtained from rheometer delta torque values with various physical properties of the TPVs like tension set and crosslink density etc. Wide angle X-ray diffraction study confirms that concentration of DCP has a strong influence on the crystallinity of PP, which might affect the final physical properties of TPVs. The recyclability and ageing characteristics of these TPVs are also found excellent.

Attribute based selection of thermoplastic resin for vacuum infusion process

DEFF Research Database (Denmark)

Prabhakaran, R.T. Durai; Lystrup, Aage; Løgstrup Andersen, Tom

2011-01-01

The composite industry looks toward a new material system (resins) based on thermoplastic polymers for the vacuum infusion process, similar to the infusion process using thermosetting polymers. A large number of thermoplastics are available in the market with a variety of properties suitable...... for different engineering applications, and few of those are available in a not yet polymerised form suitable for resin infusion. The proper selection of a new resin system among these thermoplastic polymers is a concern for manufactures in the current scenario and a special mathematical tool would...... be beneficial. In this paper, the authors introduce a new decision making tool for resin selection based on significant attributes. This article provides a broad overview of suitable thermoplastic material systems for vacuum infusion process available in today’s market. An illustrative example—resin selection...

Solvent-free thermoplastic-poly(dimethylsiloxane) bonding mediated by UV irradiation followed by gas-phase chemical deposition of an adhesion linker

Science.gov (United States)

Ahn, S. Y.; Lee, N. Y.

2015-07-01

Here, we introduce a solvent-free strategy for bonding various thermoplastic substrates with poly(dimethylsiloxane) (PDMS) using ultraviolet (UV) irradiation followed by the gas-phase chemical deposition of aminosilane on the UV-irradiated thermoplastic substrates. The thermoplastic substrates were first irradiated with UV for surface hydrophilic treatment and were then grafted with vacuum-evaporated aminosilane, where the alkoxysilane side reacted with the oxidized surface of the thermoplastic substrate. Next, the amine-terminated thermoplastic substrates were treated with corona discharge to oxidize the surface and were bonded with PDMS, which was also oxidized via corona discharge. The two substrates were then hermetically sealed and pressed under atmospheric pressure for 30 min at 60 °C. This process enabled the formation of a robust siloxane bond (Si-O-Si) between the thermoplastic substrate and PDMS under relatively mild conditions using an inexpensive and commercially available UV lamp and Tesla coil. Various thermoplastic substrates were examined for bonding with PDMS, including poly(methylmethacrylate) (PMMA), polycarbonate (PC), poly(ethyleneterephthalate) (PET) and polystyrene (PS). Surface characterizations were performed by measuring the contact angle and performing x-ray photoelectron spectroscopy analysis, and the bond strength was analyzed by conducting various mechanical force measurements such as pull, delamination, leak and burst tests. The average bond strengths for the PMMA-PDMS, PC-PDMS, PET-PDMS and PS-PDMS assemblies were measured at 823.6, 379.3, 291.2 and 229.0 kPa, respectively, confirming the highly reliable performance of the introduced bonding strategy.

Skin-inspired hydrogel-elastomer hybrids with robust interfaces and functional microstructures

Science.gov (United States)

Yuk, Hyunwoo; Zhang, Teng; Parada, German Alberto; Liu, Xinyue; Zhao, Xuanhe

2016-06-01

Inspired by mammalian skins, soft hybrids integrating the merits of elastomers and hydrogels have potential applications in diverse areas including stretchable and bio-integrated electronics, microfluidics, tissue engineering, soft robotics and biomedical devices. However, existing hydrogel-elastomer hybrids have limitations such as weak interfacial bonding, low robustness and difficulties in patterning microstructures. Here, we report a simple yet versatile method to assemble hydrogels and elastomers into hybrids with extremely robust interfaces (interfacial toughness over 1,000 Jm-2) and functional microstructures such as microfluidic channels and electrical circuits. The proposed method is generally applicable to various types of tough hydrogels and diverse commonly used elastomers including polydimethylsiloxane Sylgard 184, polyurethane, latex, VHB and Ecoflex. We further demonstrate applications enabled by the robust and microstructured hydrogel-elastomer hybrids including anti-dehydration hydrogel-elastomer hybrids, stretchable and reactive hydrogel-elastomer microfluidics, and stretchable hydrogel circuit boards patterned on elastomer.

Radiation Curing of Rubber/Thermoplastic Composites Containing Different Inorganic Fillers

International Nuclear Information System (INIS)

EL-Zayat, M.M.M.

2012-01-01

Blending of polymeric materials has proved to be a successful method for preparing new polymeric materials having not only the main properties of the blends components but also new modification as well as specific ones. High density polyethylene (HDPE) and acrylonitrile butadiene rubber (NBR) are both soild and constitute the blend components to be investigated in present study and hence the method of mechanical blending is the most suitable one for its preparation . HDPE thermoplastic is a semi – crystalline polymer ; on the other hand , NBR elastomer is totally amorphous polymer. Both polymers are categorized as crosslinking polymers with respect to ionizing gamma rays with different extents. In order to increase the efficiency of irradiation curing of such NBR/HDPE blend , it may be required to add suitable additives such as reinforcing fillers that may increase the extent of crosslinking at the same irradiation dose . Thus synthetic fillers are used commercially in industrial processing of rubber formulation due to its specific characteristics and hence its high reinforcing capacity and suitable price . To follow property changes occurred to the blend as well as its composites , measurements have been done to monitor the changes that happened to mechanical, physical and thermal properties as a function of irradiation dose and composition of blends and composites.

Hot-embossing of microstructures on addition-curing polydimethylsiloxane films

DEFF Research Database (Denmark)

Vudayagiri, Sindhu; Yu, Liyun; Hassouneh, Suzan Sager

2013-01-01

) film, which is thermosetting elastomer, was established based on the existing and widely applied technology for thermoplasts. We focus on hot-embossing as it is one of the simplest, most cost-effective and time saving methods for replicating structures for thermoplasts. Addition curing silicones...

Electromechanical response of silicone dielectric elastomers

Science.gov (United States)

Cârlescu, V.; Prisăcaru, G.; Olaru, D.

2016-08-01

This paper presents an experimental technique to investigate the electromechanical properties of silicone dielectric elastomers actuated with high DC electric fields. A non-contact measurement technique is used to capture and monitor the thickness strain (contraction) of a circular film placed between two metallic disks electrodes. Two active fillers such as silica (10, 15 and 30 wt%) and barium titanate (5 and 15 wt%) were incorporated in order to increase the actuation performance. Thickness strain was measured at HV stimuli up to 4.5 kV and showed a quadratic dependence against applied electric field indicating that the induced strain is triggered by the Maxwell effect and/or electrostriction phenomenon as reported in literature. The actuation process evidences a rapid contraction upon HV activation and a slowly relaxation when the electrodes are short-circuit due to visco-elastic nature of elastomers. A maximum of 1.22 % thickness strain was obtained at low actuating field intensity (1.5 V/pm) comparable with those reported in literature for similar dielectric elastomer materials.

Better fuel handling system performance through improved elastomers and seals

Energy Technology Data Exchange (ETDEWEB)

Wensel, R G; Metcalfe, R [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

1997-12-31

In the area of elastomers, tests have identified specific compounds that perform well in each class of CANDU service. They offer gains in service life, sometimes by factors of ten or more. Moreover, the aging characteristics of these specific compounds are being thoroughly investigated, whereas many elastomers used previously were either non-specific or their aging was unknown. In this paper the benefits of elastomer upgrading, as well as the deficiencies of current station elastomer practices, are discussed in the context of fuel handling equipment. Guidelines for procurement, storage, handling and condition monitoring of elastomer seals are outlined. (author). 3 figs.

Better fuel handling system performance through improved elastomers and seals

International Nuclear Information System (INIS)

Wensel, R.G.; Metcalfe, R.

1996-01-01

In the area of elastomers, tests have identified specific compounds that perform well in each class of CANDU service. They offer gains in service life, sometimes by factors of ten or more. Moreover, the aging characteristics of these specific compounds are being thoroughly investigated, whereas many elastomers used previously were either non-specific or their aging was unknown. In this paper the benefits of elastomer upgrading, as well as the deficiencies of current station elastomer practices, are discussed in the context of fuel handling equipment. Guidelines for procurement, storage, handling and condition monitoring of elastomer seals are outlined. (author). 3 figs

Improvement of Physico-Chemical Properties of Recycled (Elastomers /Thermoplastics) Composites using Ionizing Radiation

International Nuclear Information System (INIS)

Ibrahim, M.Y.E.A.

2013-01-01

Recycling of ground tire rubber (GRT) not only solves the waste disposal problem and maintains environmental quality, but also saves the valuable and limited resource of fossil feedstock. The major problem in the recycling of rubber-like materials such as tires is the cross linked molecular structure of already vulcanized rubber, which not only prevents the softening and processing of waste rubber particles but also inhibits binding of the powder surface to the virgin material. Several reclamation methods have proposed to overcome these barriers, which have basically followed two main approaches: (1) the de vulcanization of cured rubber and (2) the surface modifications of waste particles. The de vulcanization of rubber causes the cleavage of crosslinks via chemical treatments, which make used rubber suitable to be reformulated and recurred into new articles. In consequence, this work is mainly aimed to prepare of de vulcanized rubber (DR) and evaluating mechanical, thermal, and morphological properties of the thermoplastic vulcanizations (TPVs) based on de vulcanized rubber blended with polypropylene, EPDM using peroxide under the effect of radiation dose and DR feed ratio. The efficiency of the compounding process has been examined by infrared spectroscopy (FTIR), X-ray diffraction and scanning electron microscopy (SEM). The mechanical and thermal behaviors of the blends composed of de vulcanized rubber (DR) , high crystalline polypropylene (PP) and EPDM in different proportions were studied. Evaluation of the mechanical and thermal properties of the developed blends, unirradiated and gamma irradiated, was carried out using tensile strength (Ts), elongation at break (Eb), hardness, TGA and DSC measurements.

Improved reliability, maintainability and safety through elastomer upgrading

International Nuclear Information System (INIS)

Wensel, R.; Wittich, K.C.

1995-01-01

Equipment in nuclear plants has historically contained whatever elastomer each component supplier traditionally used for corresponding non-nuclear service. The resulting proliferation of elastomer compounds, many of which are far from optimal for the service conditions (e.g., pressure, temperature, radiation, etc.), has multiplied the costs to provide station reliability, maintainability and safety. Cost-effective improvements are being achieved in CANDU plants by upgrading and standardizing on a handful of high performing elastomer compounds. These upgraded materials offer significant gains in service life over the materials they replace (often by factors of 2 or more). This rationalization of elastomer compounds also facilitates the EQ process for safety-related equipment. Detailed test data on aging is currently being generated for these specific elastomers, encompassing the conditions and media (air, water, oil) common in CANDU service. Two key elements characterize this testing. First, each result is specific to the compound used in the test, and second, it is specific to the tested failure mode (e.g., compression set, extrusion, fracture, etc.). Having fewer, but more thoroughly tested compounds, avoids the penalty (associated with poorly characterized materials) of having to replace parts prematurely because of conservatism, while maintaining safe, reliable service. This paper provides an overview of this approach covering: the benefits of compound rationalization; and the how and why of establishing relevant failure criteria; appropriate quality assurance to maintain EQ; procurement, storage and handling guidelines; and monitoring and predicting in-service degradation. (author)

Multi-scale thermal stability of a hard thermoplastic protein-based material

Science.gov (United States)

Latza, Victoria; Guerette, Paul A.; Ding, Dawei; Amini, Shahrouz; Kumar, Akshita; Schmidt, Ingo; Keating, Steven; Oxman, Neri; Weaver, James C.; Fratzl, Peter; Miserez, Ali; Masic, Admir

2015-09-01

Although thermoplastic materials are mostly derived from petro-chemicals, it would be highly desirable, from a sustainability perspective, to produce them instead from renewable biopolymers. Unfortunately, biopolymers exhibiting thermoplastic behaviour and which preserve their mechanical properties post processing are essentially non-existent. The robust sucker ring teeth (SRT) from squid and cuttlefish are one notable exception of thermoplastic biopolymers. Here we describe thermoplastic processing of squid SRT via hot extrusion of fibres, demonstrating the potential suitability of these materials for large-scale thermal forming. Using high-resolution in situ X-ray diffraction and vibrational spectroscopy, we elucidate the molecular and nanoscale features responsible for this behaviour and show that SRT consist of semi-crystalline polymers, whereby heat-resistant, nanocrystalline β-sheets embedded within an amorphous matrix are organized into a hexagonally packed nanofibrillar lattice. This study provides key insights for the molecular design of biomimetic protein- and peptide-based thermoplastic structural biopolymers with potential biomedical and 3D printing applications.

Crosslinking of thermoplastic composites using electron beam radiation

International Nuclear Information System (INIS)

Strong, A.B.; Black, S.R.; Bryce, G.R.; Olcott, D.D.

1991-01-01

The crosslinking of thermoset materials has been clearly demonstrated to improve many desirable physical and chemical properties for composite applications. While thermoplastic resins also offer many advantages for composite applications, they are not crosslinked and, therefore, may not meet the same property criteria as crosslinked thermosets. Electron beams have been used successfully for crosslinking non-reinforced thermoplastic materials. Electron beams have also been used for curing composite thermoset materials. This research utilizes electron beams to crosslink high performance thermoplastic composite materials (PEEK and PPS with glass and carbon fibers). The tensile strength and tensile modulus are compared under various crosslinking conditions. The method is found to have some advantages in potentially improving physical properties of thermoplastic composite materials

A simple method for reducing inevitable dielectric loss in high-permittivity dielectric elastomers

DEFF Research Database (Denmark)

Madsen, Frederikke Bahrt; Yu, Liyun; Mazurek, Piotr Stanislaw

2016-01-01

elastomer matrix, with high dielectric permittivity and a low Young's modulus, aligned with no loss of mechanical stability, was prepared through the use of commercially available chloropropyl-functional silicone oil mixed into a tough commercial liquid silicone rubber silicone elastomer. The addition...... also decreased the dielectric losses of an elastomer containing dielectric permittivity-enhancing TiO2 fillers. Commercially available chloropropyl-functional silicone oil thus constitutes a facile method for improved silicone DEs, with very low dielectric losses.......Commercial viability of dielectric elastomers (DEs) is currently limited by a few obstacles, including high driving voltages (in the kV range). Driving voltage can be lowered by either decreasing the Young's modulus or increasing the dielectric permittivity of silicone elastomers, or a combination...

Effects of Poly(cyclohexanedimethylene terephthalate on Microstructures, Crystallization Behavior and Properties of the Poly(ester ether Elastomers

Directory of Open Access Journals (Sweden)

Yi-Cheng Feng

2017-06-01

Full Text Available To understand the role of molecular structure on the crystallization behavior of copolyester in thermoplastic poly(ether ester elastomers (TPEEs, series of poly(butylene-co-1,4-cyclohexanedimethylene terephthalate (P(BT-co-CT-b-poly(tetramethylene glycol (PTMG are synthesized through molten polycondensation process. The effects of poly(cyclohexanedimethylene terephthalate (PCT content on the copolymer are investigated by Fourier transform infrared spectroscopy (FT-IR, 1H and 13C nuclear magnetic resonance (NMR, gel permeation chromatographs (GPC, wide-angle X-ray diffraction (WAXD, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, mechanical, and visible light transmittance tests. FT-IR and NMR results confirm the incorporation of PCT onto the copolymer. WAXD and DSC indicate that the crystalline structure of the copolymers changed from α-PBT lattice to trans-PCT lattice when the molar fraction of PCT (MPCT is above 30%, while both crystallization and melting temperatures reach the minima. An increase in MPCT led to an increase in the number sequence length of PCT, the thermal stability and the visible light transmittance of the copolymer, but to a slight decrease in tensile strength and elastic modulus.

Functional silicone copolymers and elastomers with high dielectric permittivity

DEFF Research Database (Denmark)

Madsen, Frederikke Bahrt; Daugaard, Anders Egede; Hvilsted, Søren

Dielectric elastomers (DEs) are a new and promising transducer technology and are often referred to as ‘artificial muscles’, due to their ability to undergo large deformations when stimulated by electric fields. DEs consist of a soft and thin elastomeric film sandwiched between compliant electrodes......, thereby forming a capacitor [1]. Silicone elastomers are one of the most used materials for DEs due to their high efficiency, fast response times and low viscous losses. The major disadvantage of silicone elastomers is that they possess relatively low dielectric permittivity, which means that a high...... electrical field is necessary to operate the DE. The necessary electrical field can be lowered by creating silicone elastomers with higher dielectric permittivity, i.e. with a higher energy density.The aim of this work is to create new and improved silicone elastomers with high dielectric permittivity...

Phase Behavior of Three PBX Elastomers in High-Pressure Chlorodifluoromethane

Science.gov (United States)

Lee, Byung-Chul

2017-10-01

The phase equilibrium behavior data are presented for three kinds of commercial polymer-bonded explosive (PBX) elastomers in chlorodifluoromethane (HCFC22). Levapren^{{registered }} ethylene- co-vinyl acetate (LP-EVA), HyTemp^{{registered }} alkyl acrylate copolymer (HT-ACM), and Viton^{{registered }} fluoroelastomer (VT-FE) were used as the PBX elastomers. For each elastomer + HCFC22 system, the cloud point (CP) and/or bubble point (BP) pressures were measured while varying the temperature and elastomer composition using a phase equilibrium apparatus fitted with a variable-volume view cell. The elastomers examined in this study indicated a lower critical solution temperature phase behavior in the HCFC22 solvent. LP-EVA showed the CPs at temperatures of 323 K to 343 K and at pressures of 3 MPa to 10 MPa, whereas HT-ACM showed the CPs at conditions between 338 K and 363 K and between 4 MPa and 12 MPa. For the LP-EVA and HT-ACM elastomers, the BP behavior was observed at temperatures below about 323 K. For the VT-FE + HCFC22 system, only the CP behavior was observed at temperatures between 323 K and 353 K and at pressures between 6 MPa and 21 MPa. As the elastomer composition increased, the CP pressure increased, reached a maximum value at a specific elastomer composition, and then remained almost constant.

Swelling behavior of γ-ray irradiated elastomers in boiling spray solution

International Nuclear Information System (INIS)

Yagi, Toshiaki; Kusama, Yasuo; Ito, Masayuki; Okada, Sohei; Yoshikawa, Masahito; Yoshida, Kenzo

1983-05-01

Elastomers swelled significantly by water sorption during a simulated LOCA test, and this phenomenon could cause the deterioration of their mechanical and electrical properties. Many factors like as radiation, heat, the composition of spray solution, types of elastomers and their formulation, related to the phenomenon. A relationship between swelling properties of the formulation-known various elastomers and the pre-aging conditions such as radiation dose and thermal aging period was studied by measuring their swelling behaviors in boiling spray solution (water and chemical solution). All eight elastomers tested showed remarkable swelling with an increase of radiation dose when they irradiated in air. A swelling in boiling water was about twice of in chemical solution. Some types of Neoprene and Hypalons had an optimum swelling dose where they showed the maxima. Over this dose, the swelling ratio decreased with dose. When irradiated under vacuum, its swelling ratio became significantly lower than that of exposed in air. This attributed the swelling phenomena closely related to radiation oxidation degradation. (author)

Radiation cured and monomer modified silicon elastomers

International Nuclear Information System (INIS)

Eldred, R.J.

1979-01-01

A method is described for the production of a tear resistant silicone elastomer, which has improved elongation properties. This elastomer is the radiation induced reaction product of a noncured methyl vinyl silicone resin (VMQ) and uniformly dispersed therein a blend of a polyfunctional acrylic crosslinking monomer and a filler

PLA-based biodegradable and tunable soft elastomers for biomedical applications

International Nuclear Information System (INIS)

Harrane, Amine; Leroy, Adrien; Nouailhas, Hélène; Garric, Xavier; Coudane, Jean; Nottelet, Benjamin

2011-01-01

Although desirable for biomedical applications, soft degradable elastomers having balanced amphiphilic behaviour are rarely described in the literature. Indeed, mainly highly hydrophobic elastomers or very hydrophilic elastomers with hydrogel behaviours are found. In this work, we developed thermoset degradable elastomers based on the photo-cross-linking of poly(lactide)-poly(ethylene glycol)-poly(lactide) (PLA-PEG-PLA) triblock prepolymers. The originality of the proposed elastomers comes from the careful choice of the prepolymer amphiphilicity and from the possible modulation of their mechanical properties and degradation rates provided by cross-linkers of different nature. This is illustrated with the hydrophobic and rigid 2,4,6-triallyloxy-1,3,5-triazine compared to the hydrophilic and soft pentaerythritol triallyl ether. Thermal properties, mechanical properties, swelling behaviours, degradation rates and cytocompatibility have been evaluated. Results show that it is possible to generate a family of degradable elastomers covering a broad range of properties from a single biocompatible and biodegradable prepolymer.

Types and properties of elastomer materials used in CANDU reactor

Energy Technology Data Exchange (ETDEWEB)

You, Ho Sik; Jeong, Jin Kon [Korea Atomic Energy Research Institute, Daeduk (Korea, Republic of)

1996-05-01

Properties and kinds of elastomer materials used in a CANDU power plant have been described. The elastomer materials have been used as a sealing material in the components f nuclear power plant since they have many excellent properties that can not be seen in other materials. It is very important to select proper elastomer materials used in the nuclear power plant are required to have resistance to temperature as well as radiation. According to the experimental results performed at some laboratories including the Chalk River Laboratory of AECL, elastomer materials with high resistance to temperature and radiation are Nitrile, Ethylene, Propylene and Butyl. These materials have been used in a lot of components of Wolsong unit 1 and Wolsong 2, 3 and 4 which are under elastomer material. Therefore, the studies on the standardization are currently under way to limit about 10 different kinds of elastomer materials to be used in the plant. 16 tabs., 1 fig., 12 refs. (Author) .new.

Synthetic Strategies for High Dielectric Constant Silicone Elastomers

DEFF Research Database (Denmark)

Madsen, Frederikke Bahrt

synthetic strategies were developed in this Ph.D. thesis, in order to create silicone elastomers with high dielectric constants and thereby higher energy densities. The work focused on maintaining important properties such as dielectric loss, electrical breakdown strength and elastic modulus....... The methodology therefore involved chemically grafting high dielectric constant chemical groups onto the elastomer network, as this would potentially provide a stable elastomer system upon continued activation of the material. The first synthetic strategy involved the synthesis of a new type of cross...... extender’ that allowed for chemical modifications such as Cu- AAC. This route was promising for one-pot elastomer preparation and as a high dielectric constant additive to commercial silicone systems. The second approach used the borane-catalysed Piers-Rubinsztajn reaction to form spatially well...

Modelling of the viscoelastic behaviour of steel reinforced thermoplastic pipes

NARCIS (Netherlands)

Kruijer, M.P.; Warnet, Laurent; Akkerman, Remko

2006-01-01

This paper describes the analysis of the time dependent behaviour of a steel reinforced thermoplastic pipe. This new class of composite pipes is constructed of a HDPE (high-density polyethylene) liner pipe, which is over wrapped with two layers of thermoplastic tape. The thermoplastic tapes are

Unraveling the evolutionary scenario of the hobo element in populations of Drosophila melanogaster and D. simulans in South America using the TPE repeats as markers

Directory of Open Access Journals (Sweden)

Geovani T. Ragagnin

2016-03-01

Full Text Available Abstract Transposable elements (TEs are nucleotide sequences found in most studied genomes. These elements are highly diversified and have a large variation in nucleotide structure and mechanisms of transposition. hobo is a member of class II, belonging to hAT superfamily, described inDrosophila melanogaster, and it presents in its Open Reading Frame, a repetitive region encoding the amino acids threonine-proline-glutamic acid (TPE, which shows variability in the number of repeats in some regions of the world. Due to this variability some evolutionary scenarios of the hobo element are discussed, such as the scenario of the invasion of hobo element in populations ofD. melanogaster. In the present study, we investigated 22 DNA sequences of D. melanogaster and seven sequences ofD. simulans, both from South America, to check the number of repetitions of TPE, in order to clarify the evolutionary scenario of thehobo element in these populations. Our results showed a monomorphism in populations of both species in South America, with only three TPE repeats. Hence, we discuss and propose an evolutionary scenario of the invasion of the hobo element in populations of D. melanogaster and D. simulans.

Electrical Breakdown and Mechanical Ageing in Dielectric Elastomers

DEFF Research Database (Denmark)

Zakaria, Shamsul Bin

Dielectric elastomers (DE) are used in various applications, such as artificial eye lids, pressure sensors and human motion energy generators. For many applications, one of the major factors that limits the DE performance is premature electrical breakdown. There are many approaches that have been......, the lifetime of elastomer materials needs further investigation. Therefore, in the second strategy, several DE parameters such as Young’s moduli, breakdown strengths and dielectric permittivities of PDMS elastomers filled with hard filler particles were investigated after being subjected to pre...

Theory of Dielectric Elastomers

Science.gov (United States)

2010-10-25

feature of life is to receive and process information from the environment, and then move. The movements are responsible for diverse functions, far...beyond the function of going from place to place. For example, an octopus can change its color at an astonishing speed, for camouflage and signaling...in engineering are indeed apt in mimicking the salient feature of life: movements in response to stimuli. An electric field can cause an elastomer

Thermoforming of Continuous Fibre Reinforced Thermoplastic Composites

International Nuclear Information System (INIS)

McCool, Rauri; Murphy, Adrian; Wilson, Ryan; Jiang Zhenyu; Price, Mark

2011-01-01

The introduction of new materials, particularly for aerospace products, is not a simple, quick or cheap task. New materials require extensive and expensive qualification and must meet challenging strength, stiffness, durability, manufacturing, inspection and maintenance requirements. Growth in industry acceptance for fibre reinforced thermoplastic composite systems requires the determination of whole life attributes including both part processing and processed part performance data. For thermoplastic composite materials the interactions between the processing parameters, in-service structural performance and end of life recyclability are potentially interrelated. Given the large number and range of parameters and the complexity of the potential relationships, understanding for whole life design must be developed in a systematic building block approach. To assess and demonstrate such an approach this article documents initial coupon level thermoforming trials for a commercially available fibre reinforced thermoplastic laminate, identifying the key interactions between processing and whole life performance characteristics. To examine the role of the thermoforming process parameters on the whole life performance characteristics of the formed part requires a series of manufacturing trials combined with a series of characterisation tests on the manufacturing trial output. Using a full factorial test programme and considering all possible process parameters over a range of potential magnitudes would result in a very large number of manufacturing trials and accompanying characterisation tests. Such an approach would clearly be expensive and require significant time to complete, therefore failing to address the key requirement for a future design methodology capable of rapidly generating design knowledge for new materials and processes. In this work the role of mould tool temperature and blank forming temperature on the thermoforming of a commercially available

Fluoridated elastomers: effect on the microbiology of plaque.

Science.gov (United States)

Benson, Philip E; Douglas, C W Ian; Martin, Michael V

2004-09-01

The objective of this study was to investigate the effect of fluoridated elastomeric ligatures on the microbiology of local dental plaque in vivo. This randomized, prospective, longitudinal, clinical trial had a split-mouth crossover design. The subjects were 30 patients at the beginning of their treatment with fixed orthodontic appliances in the orthodontic departments of the Liverpool and the Sheffield dental hospitals in the United Kingdom. The study consisted of 2 experimental periods of 6 weeks with a washout period between. Fluoridated elastomers were randomly allocated at the first visit to be placed around brackets on tooth numbers 12, 11, 33 or 22, 21, 43. Nonfluoridated elastomers were placed on the contralateral teeth. Standard nonantibacterial fluoridated toothpaste and mouthwash were supplied. After 6 weeks (visit 2), the elastomers were removed, placed in transport media, and plated on agar within 2 hours. Nonfluoridated elastomers were placed on all brackets for 1 visit to allow for a washout period. At visit 3, fluoridated elastomers were placed on the teeth contralateral to those that received them at visit 1. At visit 4, the procedures at visit 2 were repeated. Samples were collected on visits 2 and 4. A logistic regression was performed, with the presence or absence of streptococcal or anaerobic growth as the dependent variable. A mixed-effects analysis of variance was carried out with the percentage of streptococcal or anaerobic bacterial count as the dependent variable. The only significant independent variables were the subject variable (P =bacterial count and the visit variable for the percentage of streptococcal count (P =fluoridated or nonfluoridated elastomers was not significant for percentage of either streptococcal (P =.288) or anaerobic count (P =.230). Fluoridated elastomers are not effective at reducing local streptococcal or anaerobic bacterial growth after a clinically relevant time in the mouth.

Semi-active control of a sandwich beam partially filled with magnetorheological elastomer

Science.gov (United States)

Dyniewicz, Bartłomiej; Bajkowski, Jacek M.; Bajer, Czesław I.

2015-08-01

The paper deals with the semi-active control of vibrations of structural elements. Elastomer composites with ferromagnetic particles that act as magnetorheological fluids are used. The damping coefficient and the shear modulus of the elastomer increases when it is exposed to an electro-magnetic field. The control of this process in time allows us to reduce vibrations more effectively than if the elastomer is permanently exposed to a magnetic field. First the analytical solution for the vibrations of a sandwich beam filled with an elastomer is given. Then the control problem is defined and applied to the analytical formula. The numerical solution of the minimization problem results in a periodic, perfectly rectangular control function if free vibrations are considered. Such a temporarily acting magnetic field is more efficient than a constantly acting one. The surplus reaches 20-50% or more, depending on the filling ratio of the elastomer. The resulting control was verified experimentally in the vibrations of a cantilever sandwich beam. The proposed semi-active control can be directly applied to engineering vibrating structural elements, for example helicopter rotors, aircraft wings, pads under machines, and vehicles.

Thermoplastic liners for carbon steel pipelines

Energy Technology Data Exchange (ETDEWEB)

Mehdi, Mauyed S.; AlDossary, Abdullah K. [Saudi Aramco, Dhahran (Saudi Arabia)

2009-12-19

Materials selection for pipe and fittings used to convey corrosive fluids has often been a challenge. Traditionally, exotic Corrosion Resistant Alloys (CRA) have been used in corrosive environments despite their high cost. Plastic lined carbon steel piping offers a cost effective alternative to the use of CRAs by eliminating corrosion, significantly reducing the use of toxic chemicals and the heavy metal usually present in CRAs. Thermoplastic Liners offer the combination of corrosion resistance and mechanical strength, which are unachievable with singular materials. Under pressure conditions, the liner is fully supported by the metalwork, while under vacuum conditions, the liner must be thick enough along with venting system to withstand the collapsing forces created by the negative pressure. Plastic liners have been used successfully to line and protect metallic pipelines for many years and have become an indispensable requirement of the oil and gas industry particularly with water injection and hydrocarbon services. In the case of internally corroded pipes, the use of thermoplastic liners for rehabilitation is an option to extend the lifetime of companies' assets, reduce maintenance cost and increase intervals between T and Is. For new construction, plastic liners in carbon steel pipes can compete technically and economically with pipelines of CRA materials and other corrosion inhibition systems. This paper describes various design features, installations of thermoplastic liners in comparison to other corrosion inhibition methods. (author)

Production and Mechanical Characterization of Ballistic Thermoplastic Composite Materials

OpenAIRE

D. Korsacilar; C. Atas

2014-01-01

In this study, first thermoplastic composite materials /plates that have high ballistic impact resistance were produced. For this purpose, the thermoplastic prepreg and the vacuum bagging technique were used to produce a composite material. Thermoplastic prepregs (resin-impregnated fiber) that are supplied ready to be used, namely high-density polyethylene (HDPE) was chosen as matrix and unidirectional glass fiber was used as reinforcement. In order to compare the fiber c...

Dosimetric effects of thermoplastic immobilizing devices on skin dose

International Nuclear Information System (INIS)

Adu-Poku Olivia

2017-07-01

This work shows the increase in surface dose caused by thermoplastic immobilizing masks used for positioning and immobilization of patients. Thermoplastics are organic materials which soften when they are heated. They can be formed after softening and retain their final shape when cooled. The use of these thermoplastic masks are relevant during patient treatment. However, it can lead to an increased skin dose. Measurements were done at source-to-surface distance of 80 cm for external radiation beams produced by cobalt 60 using the Farmer type ionization chamber and the Unidos electrometer. Measurements were carried out using various mask thicknesses and no mask material on a solid water phantom. The thermoplastic percentage depth dose (PDD), equivalent thickness of water of the various thicknesses of the mask and surface doses were determined. The increase in the surface dose caused by the thermoplastic mask was compared by looking at the PDD at depth 0 with and without the mask present and was found to increase between 0.76 and 0.79% with no mask for a field size of 5 x 5 cm 2 . It was found that, the presence of the mask shifted the percentage depth dose curve to lower values. The physical thermoplastic thickness was measured to be between 2.30 and 1.80 mm, and the equivalent thicknesses of water, d e , were determined to be 1.2, 1.15, 1.10 and 1.09 and 1.00 mm for the unstretched, 5 cm stretched, 10 cm stretched, 15 cm stretched and 20 cm stretched masks, respectively. This meant that, as the mask thickness decreased, its water equivalent thickness also decreased. The presence of the mask material did not increase the skin dose significantly ( less than 1%). (au)

Radiation cured acrylonitrile--butadiene elastomers

International Nuclear Information System (INIS)

Eldred, R.J.

1976-01-01

In accordance with a preferred embodiment of this invention, the ultimate elongation of an electron beam radiation cured acrylonitrile-butadiene elastomer is significantly increased by the incorporation of a preferred noncrosslinking monomer, glycidyl methacrylate, in combination with the conventional crosslinking monomer, trimethylolpropanetrimethacrylate, prior to the radiation curing process

Ductile thermoset polymers via controlling network flexibility.

Science.gov (United States)

Hameed, N; Salim, N V; Walsh, T R; Wiggins, J S; Ajayan, P M; Fox, B L

2015-06-18

We report the design and synthesis of a polymer structure from a cross-linkable epoxy-ionic liquid system which behaves like a hard and brittle epoxy thermoset, perfectly ductile thermoplastic and an elastomer, all depending on controllable network compositions.

Start-up assist by magnetized plasma flow injection in TPE-RX reversed-field pinch

Energy Technology Data Exchange (ETDEWEB)

Asai, T. [College of Science and Technology, Nihon University, 1-8 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan)]. E-mail: asai@phys.cst.nihon-u.ac.jp; Nagata, M. [Graduate School of Engineering, University of Hyogo, Himeji (Japan); Koguchi, H. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Hirano, Y. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Sakakita, H. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Yambe, K. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan); Kiyama, S. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)

2006-11-15

A reversed-field pinch (RFP) start-up assisted by a magnetized plasma flow injection was demonstrated for the first time on a TPE-RX machine. This sequence of experiments aimed to establish a new method of ionization, gas-fill and helicity injection in the start-up phase of an RFP. In this start-up method, magnetized and well-ionized plasma is formed by a magnetized coaxial plasma gun and injected into the torus chamber as an initial pre-ionized plasma for RFP formation. In the initial experiments, attenuated density pump-out and comparatively slow decay of the toroidal flux and plasma current were observed as evidence of its being an effective start-up method.

ASSESSMENT OF THE INFLUENCE OF RADIATION AND DEFORMATION ON THE ELASTOMER DETERIORATION BY USING FUZZY LOGIC

Directory of Open Access Journals (Sweden)

Jasminka Bonato

2017-01-01

Full Text Available Elastomers belong to the group of polymer materials and they have an important role as technical material in the shipbuilding industry. The radiation crosslinking of elastomers shows significant advantages over chemical crosslinking. It can improve mechanical strength, resistance to chemicals and insulation properties of elastomers. An undesirable side reaction, which can occur during radiation, is the degradation process. This results in cracks breaking, chemical disintegration and reduction of mechanical properties of elastomers. In this paper fuzzy logic is used to estimate the influence of radiation and deformation on the behavior of elastomer samples. A Gaussian model is created according to both the experts' experience and the measuring data. The results of the model are calculated by using the Normalized Roth Mean Square Error (NRMSE and the Roth Mean Square Error (RMSE. The so developed model gives new conceptions, which offer a possibility to improve the application of elastomer materials.

Rigidity-tuning conductive elastomer

Science.gov (United States)

Shan, Wanliang; Diller, Stuart; Tutcuoglu, Abbas; Majidi, Carmel

2015-06-01

We introduce a conductive propylene-based elastomer (cPBE) that rapidly and reversibly changes its mechanical rigidity when powered with electrical current. The elastomer is rigid in its natural state, with an elastic (Young’s) modulus of 175.5 MPa, and softens when electrically activated. By embedding the cPBE in an electrically insulating sheet of polydimethylsiloxane (PDMS), we create a cPBE-PDMS composite that can reversibly change its tensile modulus between 37 and 1.5 MPa. The rigidity change takes ˜6 s and is initiated when a 100 V voltage drop is applied across the two ends of the cPBE film. This magnitude of change in elastic rigidity is similar to that observed in natural skeletal muscle and catch connective tissue. We characterize the tunable load-bearing capability of the cPBE-PDMS composite with a motorized tensile test and deadweight experiment. Lastly, we demonstrate the ability to control the routing of internal forces by embedding several cPBE-PDMS ‘active tendons’ into a soft robotic pneumatic bending actuator. Selectively activating the artificial tendons controls the neutral axis and direction of bending during inflation.

Rigidity-tuning conductive elastomer

International Nuclear Information System (INIS)

Shan, Wanliang; Diller, Stuart; Tutcuoglu, Abbas; Majidi, Carmel

2015-01-01

We introduce a conductive propylene-based elastomer (cPBE) that rapidly and reversibly changes its mechanical rigidity when powered with electrical current. The elastomer is rigid in its natural state, with an elastic (Young’s) modulus of 175.5 MPa, and softens when electrically activated. By embedding the cPBE in an electrically insulating sheet of polydimethylsiloxane (PDMS), we create a cPBE–PDMS composite that can reversibly change its tensile modulus between 37 and 1.5 MPa. The rigidity change takes ∼6 s and is initiated when a 100 V voltage drop is applied across the two ends of the cPBE film. This magnitude of change in elastic rigidity is similar to that observed in natural skeletal muscle and catch connective tissue. We characterize the tunable load-bearing capability of the cPBE–PDMS composite with a motorized tensile test and deadweight experiment. Lastly, we demonstrate the ability to control the routing of internal forces by embedding several cPBE–PDMS ‘active tendons’ into a soft robotic pneumatic bending actuator. Selectively activating the artificial tendons controls the neutral axis and direction of bending during inflation. (paper)

Processing technology for advanced fibre composites with thermoplastic matrices

Energy Technology Data Exchange (ETDEWEB)

Lystrup, Aa. [Risoe National Lab., Materials Research Dept., Roskilde (Denmark)

1997-12-31

Technologies and semi-raw materials for the manufacture of thermoplastic composites with continuous fibres are discussed. Autoclave consolidation, vacuum consolidation and press consolidation are all processes which are suitable for the manufacture of components with a three dimensional geometry. Autoclave consolidation is primarily for high quality components with high fibre content and complex geometry; using vacuum consolidation, very large components can be produced without the need of an autoclave, and the press consolidation technique is a very fast process suitable for mass production of smaller parts. Filament winding is used primarily for the manufacture of rotationally symmetrical components, and some of the technologies in use are winding with a continuously in-situ consolidation, winding inside an oven and room temperature winding followed by an autoclave consolidation. Semi-raw materials for thermoplastic composites exist as both prepregs and postpregs in many different forms, of which many are still under development. Some of the basic processing properties for the different types of semi-raw materials and most commonly used thermoplastic polymers are given. (au) 37 refs.

Non-silicon substrate bonding mediated by poly(dimethylsiloxane) interfacial coating

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hainan [Department of BioNano Technology, Gachon University, Gyeonggi-do 461-701 (Korea, Republic of); Lee, Nae Yoon, E-mail: nylee@gachon.ac.kr [Department of BioNano Technology, Gachon University, Gyeonggi-do 461-701 (Korea, Republic of); Gachon Medical Research Institute, Gil Medical Center, Inchon 405-760 (Korea, Republic of)

2015-02-01

Graphical abstract: Low-molecular-weight PDMS coating on the surfaces of non-silicon substrates such as thermoplastics ensures permanent sealing with a silicone elastomer, PDMS, simply by surface oxidization followed by ambient condition bonding, mediated by a robust siloxane bond formation at the interface. - Highlights: • Non-silicon thermoplastic was bonded with poly(dimethylsiloxane) silicone elastomer. • Low-molecular-weight PDMS interfacial layer was chemically coated on thermoplastic. • Bonding was realized by corona treatment and physical contact under ambient condition. • Bonding is universally applicable regardless of thermoplastic type and property. • Homogeneous PDMS-like microchannel was obtained inside the thermoplastic-PDMS microdevice. - Abstract: In this paper, we introduce a simple and robust strategy for bonding poly(dimethylsiloxane) (PDMS) with various thermoplastic substrates to fabricate a thermoplastic-based closed microfluidic device and examine the feasibility of using the proposed method for realizing plastic–plastic bonding. The proposed bonding strategy was realized by first coating amine functionality on an oxidized thermoplastic surface. Next, the amine-functionalized surface was reacted with a monolayer of low-molecular-weight PDMS, terminated with epoxy functionality, by forming a robust amine-epoxy bond. Both the PDMS-coated thermoplastic and PDMS were then oxidized and permanently assembled at 25 °C under a pressure of 0.1 MPa for 15 min, resulting in PDMS-like surfaces on all four inner walls of the microchannel. Surface characterizations were conducted, including water contact angle measurement, X-ray photoelectron spectroscopy (XPS), and fluorescence measurement, to confirm the successful coating of the thin PDMS layer on the plastic surface, and the bond strength was analyzed by conducting a peel test, burst test, and leakage test. Using the proposed method, we could successfully bond various thermoplastics such

Fracture and healing of elastomers: A phase-transition theory and numerical implementation

Science.gov (United States)

Kumar, Aditya; Francfort, Gilles A.; Lopez-Pamies, Oscar

2018-03-01

A macroscopic theory is proposed to describe, explain, and predict the nucleation and propagation of fracture and healing in elastomers undergoing arbitrarily large quasistatic deformations. The theory, which can be viewed as a natural generalization of the phase-field approximation of the variational theory of brittle fracture of Francfort and Marigo (1998) to account for physical attributes innate to elastomers that have been recently unveiled by experiments at high spatio-temporal resolution, rests on two central ideas. The first one is to view elastomers as solids capable to undergo finite elastic deformations and capable also to phase transition to another solid of vanishingly small stiffness: the forward phase transition serves to model the nucleation and propagation of fracture while the reverse phase transition models the possible healing. The second central idea is to take the phase transition to be driven by the competition between a combination of strain energy and hydrostatic stress concentration in the bulk and surface energy on the created/healed new surfaces in the elastomer. From an applications point of view, the proposed theory amounts to solving a system of two coupled and nonlinear PDEs for the deformation field and an order parameter, or phase field. A numerical scheme is presented to generate solutions for these PDEs in N = 2 and 3 space dimensions. This is based on an efficient non-conforming finite-element discretization, which remains stable for large deformations and elastomers of any compressibility, together with an implicit gradient flow solver, which is able to deal with the large changes in the deformation field that can ensue locally in space and time from the nucleation of fracture. The last part of this paper is devoted to presenting sample simulations of the so-called Gent-Park experiment. Those are confronted with recent experimental results for various types of silicone elastomers.

Voltage-stabilised elastomers with increased relative permittivity and high electrical breakdown strength by means of phase separating binary copolymer blends of silicone elastomers

DEFF Research Database (Denmark)

A Razak, Aliff Hisyam; Yu, Liyun; Skov, Anne Ladegaard

2017-01-01

Increased electrical breakdown strength and increased dielectric permittivity of silicone-based dielectric elastomers are achieved by means of the addition of so-called voltage-stabilisers prepared from PDMS–PPMS copolymers as well as PDMS–PEG copolymers in order to compensate for the negative...... effect of softness on electrical stability of silicone elastomers. The voltage-stabilised elastomer, incorporating a high-permittivity PDMS–PEG copolymer, possesses increased relative permittivity, high electrical breakdown strength, excellent network integrity and low dielectric loss and paves the way...

Collapse of triangular channels in a soft elastomer

Science.gov (United States)

Tepáyotl-Ramírez, Daniel; Lu, Tong; Park, Yong-Lae; Majidi, Carmel

2013-01-01

We extend classical solutions in contact mechanics to examine the collapse of channels in a soft elastomer. These channels have triangular cross-section and collapse when pressure is applied to the surrounding elastomer. Treating the walls of the channel as indenters that penetrate the channel base, we derive an algebraic mapping between pressure and cross-sectional area. These theoretical predictions are in strong agreement with results that we obtain through finite element analysis and experimental measurements. This is accomplished without data fitting and suggests that the theoretical approach may be generalized to a broad range of cross-sectional geometries in soft microfluidics.

Toward a predictive model for elastomer seals

Science.gov (United States)

Molinari, Nicola; Khawaja, Musab; Sutton, Adrian; Mostofi, Arash

Nitrile butadiene rubber (NBR) and hydrogenated-NBR (HNBR) are widely used elastomers, especially as seals in oil and gas applications. During exposure to well-hole conditions, ingress of gases causes degradation of performance, including mechanical failure. We use computer simulations to investigate this problem at two different length and time-scales. First, we study the solubility of gases in the elastomer using a chemically-inspired description of HNBR based on the OPLS all-atom force-field. Starting with a model of NBR, C=C double bonds are saturated with either hydrogen or intramolecular cross-links, mimicking the hydrogenation of NBR to form HNBR. We validate against trends for the mass density and glass transition temperature for HNBR as a function of cross-link density, and for NBR as a function of the fraction of acrylonitrile in the copolymer. Second, we study mechanical behaviour using a coarse-grained model that overcomes some of the length and time-scale limitations of an all-atom approach. Nanoparticle fillers added to the elastomer matrix to enhance mechanical response are also included. Our initial focus is on understanding the mechanical properties at the elevated temperatures and pressures experienced in well-hole conditions.

Zipping dielectric elastomer actuators: characterization, design and modeling

International Nuclear Information System (INIS)

Maffli, L; Rosset, S; Shea, H R

2013-01-01

We report on miniature dielectric elastomer actuators (DEAs) operating in zipping mode with an analytical model that predicts their behavior. Electrostatic zipping is a well-known mechanism in silicon MEMS to obtain large deformations and forces at lower voltages than for parallel plate electrostatic actuation. We extend this concept to DEAs, which allows us to obtain much larger out-of-plane displacements compared to silicon thanks to the softness of the elastomer membrane. We study experimentally the effect of sidewall angles and elastomer prestretch on 2.3 mm diameter actuators with PDMS membranes. With 15° and 22.5° sidewall angles, the devices zip in a bistable manner down 300 μm to the bottom of the chambers. The highly tunable bistable behavior is controllable by both chamber geometry and membrane parameters. Other specific characteristics of zipping DEAs include well-controlled deflected shape, tunable displacement versus voltage characteristics to virtually any shape, including multi-stable modes, sealing of embedded holes or channels for valving action and the reduction of the operating voltage. These properties make zipping DEAs an excellent candidate for applications such as integrated microfluidics actuators or Braille displays. (paper)

Elastomer damper performance - A comparison with a squeeze film for a supercritical power transmission shaft

Science.gov (United States)

Zorzi, E. S.; Burgess, G.; Cunningham, R.

1980-01-01

This paper describes the design and testing of an elastomer damper on a super-critical power transmission shaft. The elastomers were designed to provide acceptable operation through the fourth bending mode and to control synchronous as well as nonsynchronous vibration throughout the operating range. The design of the elastomer was such that it could be incorporated into the system as a replacement for a squeeze-film damper without a reassembly, which could have altered the imbalance of the shaft. This provided a direct comparison of the elastomer and squeeze-film dampers without having to assess the effect of shaft imbalance changes.

Toughening elastomers with sacrificial bonds and watching them break.

Science.gov (United States)

Ducrot, Etienne; Chen, Yulan; Bulters, Markus; Sijbesma, Rint P; Creton, Costantino

2014-04-11

Elastomers are widely used because of their large-strain reversible deformability. Most unfilled elastomers suffer from a poor mechanical strength, which limits their use. Using sacrificial bonds, we show how brittle, unfilled elastomers can be strongly reinforced in stiffness and toughness (up to 4 megapascals and 9 kilojoules per square meter) by introducing a variable proportion of isotropically prestretched chains that can break and dissipate energy before the material fails. Chemoluminescent cross-linking molecules, which emit light as they break, map in real time where and when many of these internal bonds break ahead of a propagating crack. The simple methodology that we use to introduce sacrificial bonds, combined with the mapping of where bonds break, has the potential to stimulate the development of new classes of unfilled tough elastomers and better molecular models of the fracture of soft materials.

The Current State of Silicone-Based Dielectric Elastomer Transducers

DEFF Research Database (Denmark)

Madsen, Frederikke Bahrt; Daugaard, Anders Egede; Hvilsted, Søren

2016-01-01

class of transducer due to their inherent lightweight and potentially large strains. For the field to progress towards industrial implementation, a leap in material devel- opment is required, specifically targeting longer lifetime and higher energy densities to provide more efficient transduction at lower...... driving voltages. In this review, the current state of sili- cone elastomers for DETs is summarised and critically discussed, including commercial elastomers, composites, polymer blends, grafted elastomers and complex network structures. For future developments in the field it is essential that all aspects...

Aging of elastomers in CANDU pressure boundary service

International Nuclear Information System (INIS)

VanBerlo, C.; Leidner, J.

1987-09-01

This report describes the properties and aging of elastomers, and examines the performance of major elastomeric components in CANDU pressure boundary service. The components examined are vacuum building roof seals, pressure relief duct seals, airlock door seals, fuelling machine hoses, and cable penetrations. For each of these components, the design requirements, technical specifications and component testing procedures are compared with applicable standards. Information on actual and recommended monitoring and maintenance methods is presented. Operational and environmental stressors are identified. Component failure modes, causes and frequencies are described, as well as the remedial action taken. Many different elastomers are used in CANDU plants, for many different applications. Standards and manufacturers' recommendations are not consistent and may vary from one component to another. Accordingly, the monitoring, maintenance and replacement practices tend to vary from one application to another, and may also be different at different stations. Recommendations are given in this report for improved monitoring and maintenance, in an attempt to provide more consistency in approach. A summary of some experiences with elastomers from non-Canadian sources is contained in the last section. 125 refs

Prolonged Tp-e Interval, Tp-e/QT Ratio and Tp-e/QTc Ratio in Patients with Type 2 Diabetes Mellitus

Directory of Open Access Journals (Sweden)

Alptug Tokatli

2016-03-01

Full Text Available BackgroundType 2 diabetes mellitus (T2DM is associated with increased risk of malignant ventricular arrhythmias. Cardiac electrical inhomogeneity may be the leading cause of the increased arrhythmic risk in patients with T2DM. The peak and the end of the T wave (Tp-e interval and associated Tp-e/QT ratio are promising measures of ventricular repolarization indicating transmural dispersion of repolarization. The aim of this study was to assess ventricular repolarization in patients with T2DM by using Tp-e interval, Tp-e/QT ratio and Tp-e/corrected QT interval (QTc ratio.MethodsForty-three patients with T2DM and 43 healthy control subjects, matched by gender and age, were studied. All participants underwent electrocardiography (ECG recording. PR, RR and QT intervals represents the ECG intervals. These are not abbreviations. In all literature these ECG intervals are written like in this text. Tp-e intervals were measured from 12-lead ECG. Rate QTc was calculated by using the Bazett's formula. Tp-e/QT ratio and Tp-e/QTc ratio were also calculated.ResultsMean Tp-e interval was significantly prolonged in patients with T2DM compared to controls (79.4±10.3, 66.4±8.1 ms, respectively; P<0.001. We also found significantly higher values of Tp-e/QT ratio and Tp-e/QTc ratio in patients with diabetes than controls (0.21±0.03, 0.17±0.02 and 0.19±0.02, 0.16±0.02, respectively; P<0.001. There was no difference in terms of the other ECG parameters between the groups.ConclusionTp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were prolonged in patients with T2DM. We concluded that T2DM leads to augmentation of transmural dispersion of repolarization suggesting increased risk for ventricular arrhythmogenesis.

Contact and friction in systems with fibre reinforced elastomers

NARCIS (Netherlands)

Rodriguez Pareja, Natalia Valentina

2012-01-01

The tribological behaviour (contact and friction) of systems that include fibre reinforced elastomers is studied in this thesis. The elastomer composite is considered to behave as a viscoelastic anisotropic continuum material. In the defined tribo-system, the most influential friction mechanism is

Role of catalysis in sustainable production of synthetic elastomers

Indian Academy of Sciences (India)

productions, the impact of synthetic elastomer business cannot be overlooked. The need of ... Keywords. Elastomers; catalysis; tyres and automobiles; mechanism; manufacturing process. 1. ..... level fractional factorial design model was also developed to ..... Polybutadiene can be manufactured by a number of pro- cesses ...

Effect of natural fibres on the mechanical properties of thermoplastic starch

Science.gov (United States)

Oniszczuk, Tomasz; Wójtowicz, Agnieszka; Moácicki, Leszek; Mitrus, Marcin; Kupryaniuk, Karol; Kusz, Andrzej; Bartnik, Grzegorz

2016-04-01

This paper presents the results covering the mechanical properties of thermoplastic potato starch granules with flax, cellulose fibre, and pine bark addition. A modified single screw extrusion-cooker TS-45 with L/D = 18 and an additional cooling section of the barrel was used as the processing unit. The establishment influence of the fibre addition, as well as the extrusion-cooker screw speed, on the mechanical properties of the thermoplastic starch granules was the main objective of the investigation. The maximum force during compression to 50% of the sample diameter, elastic modulus, and compression strength were evaluated. Significant differences were noted depending on the amount of fibre used, while only an insignificant influence of screw speed on the mechanical properties of the granulate was reported. An increased amount of fibres lowered the maximum force as well as the elastic modulus and compression strength of the thermoplastic starch granulates.

Manufacturing of a REBCO racetrack coil using thermoplastic resin aiming at Maglev application

International Nuclear Information System (INIS)

Mizuno, Katsutoshi; Ogata, Masafumi; Hasegawa, Hitoshi

2015-01-01

Highlights: • We propose a novel REBCO coil structure which applies thermoplastic resin. • The thermoplastic resin bonds the coil winding and cooling plates. • The adhesiveness of the resin is strong enough to withstand the thermal stress. • The thermoplastic resin does not cause the degradation because of its high viscosity. • We successfully made a full-scale racetrack REBCO coil with the thermoplastic resin. - Abstract: The REBCO coated conductor is a promising technology for the Maglev application in terms of its high critical temperature. The operating temperature of the on-board magnets can be around 40–50 K with the coated conductor. The REBCO coils are cooled by cryocoolers directly, and hence the thermal design of the REBCO coils significantly changes from that of LTS coils. We have developed a novel REBCO coil structure using thermoplastic resin. The coil is not impregnated and the thermoplastic resin is used to bond the coil winding and the heat transfer members, e.g. copper and aluminum plates. The viscosity of the thermoplastic resin is high enough for the thermoplastic resin not to permeate between the turns in the coil. Therefore, the thermal stress does not occur and the risk of degradation is removed. This paper contains the following three topics. First, the thermal resistance of the thermoplastic resin was measured at cryogenic temperature. Then, a small round REBCO coil was experimentally produced. It has been confirmed that the thermoplastic resin does not cause the degradation and, the adhesion between the coil winding and copper plates withstands the thermal stress. Finally, we successfully produced a full-scale racetrack REBCO coil applying the coil structure with the thermoplastic resin.

Manufacturing of a REBCO racetrack coil using thermoplastic resin aiming at Maglev application

Energy Technology Data Exchange (ETDEWEB)

Mizuno, Katsutoshi, E-mail: mizuno.katsutoshi.14@rtri.or.jp; Ogata, Masafumi; Hasegawa, Hitoshi

2015-11-15

Highlights: • We propose a novel REBCO coil structure which applies thermoplastic resin. • The thermoplastic resin bonds the coil winding and cooling plates. • The adhesiveness of the resin is strong enough to withstand the thermal stress. • The thermoplastic resin does not cause the degradation because of its high viscosity. • We successfully made a full-scale racetrack REBCO coil with the thermoplastic resin. - Abstract: The REBCO coated conductor is a promising technology for the Maglev application in terms of its high critical temperature. The operating temperature of the on-board magnets can be around 40–50 K with the coated conductor. The REBCO coils are cooled by cryocoolers directly, and hence the thermal design of the REBCO coils significantly changes from that of LTS coils. We have developed a novel REBCO coil structure using thermoplastic resin. The coil is not impregnated and the thermoplastic resin is used to bond the coil winding and the heat transfer members, e.g. copper and aluminum plates. The viscosity of the thermoplastic resin is high enough for the thermoplastic resin not to permeate between the turns in the coil. Therefore, the thermal stress does not occur and the risk of degradation is removed. This paper contains the following three topics. First, the thermal resistance of the thermoplastic resin was measured at cryogenic temperature. Then, a small round REBCO coil was experimentally produced. It has been confirmed that the thermoplastic resin does not cause the degradation and, the adhesion between the coil winding and copper plates withstands the thermal stress. Finally, we successfully produced a full-scale racetrack REBCO coil applying the coil structure with the thermoplastic resin.

Silicone elastomers with aromatic voltage stabilizers

DEFF Research Database (Denmark)

A Razak, Aliff Hisyam; Skov, Anne Ladegaard

of electron-trapping by aromatic compounds grafted to silicone backbones in a crosslinked PDMS is illustrated in Fig. 1. The electrical breakdown strength, the storage modulus and the loss modulus of the elastomer were investigated, as well as the excitation energy from the collision between electron carriers...... and benzene rings in PDMS-PPMS copolymer was measured by UV-vis spectroscopy. The developed elastomers were inherently soft with enhanced electrical breakdown strength due to delocalized pi-electrons of aromatic rings attached to the silicone backbone. The dielectric relative permittivity of PDMS...

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.

Frequency and temperature dependence of high damping elastomers

International Nuclear Information System (INIS)

Kulak, R.F.; Hughes, T.H.

1993-01-01

High damping steel-laminated elastomeric seismic isolation bearings are one of the preferred devices for isolating large buildings and structures. In the US, the current reference design for the Advanced Liquid Metal Reactor (ALMR) uses laminated bearings for seismic isolation. These bearings are constructed from alternating layers of high damping rubber and steel plates. They are typically designed for shear strains between 50 and 100% and are expected to sustain two to three times these levels for beyond design basis loading conditions. Elastomeric bearings are currently designed to provide a system frequency between 0.4 and 0.8 Hz and expected to operate between -20 and 40 degrees Centigrade. To assure proper performance of isolation bearings, it is necessary to characterize the elastomer's response under expected variations of frequency and temperature. The dynamic response of the elastomer must be characterized within the frequency range that spans the bearing acceptance test frequency, which may be as low as 0.005 Hz, and the design frequency. Similarly, the variation in mechanical characteristics of the elastomer must be determined over the design temperature range, which is between -20 and 40 degrees Centigrade. This paper reports on (1) the capabilities of a testing facility at ANL for testing candidate elastomers, (2) the variation with frequency and temperature of the stiffness and damping of one candidate elastomer, and (3) the effect of these variations on bearing acceptance testing criteria and on the choice of bearing design values for stiffness and damping

Development of procedures for calculating stiffness and damping of elastomers in engineering applications, part 7

Science.gov (United States)

Rieger, A.; Zorzi, E.

1980-01-01

An elastomer shear damper was designed, tested, and compared with the performance of the T 55 power turbine supported on the production engine roller bearing support. The Viton 70 shear damper was designed so that the elastomer damper could be interchanged with the production T 55 power turbine roller bearing support. The results show that the elastomer sheer dampener permitted stable operation of the power turbine to the maximum operating speed of 16,000 rpm.

Characterisation of metal–thermoplastic composite hybrid joints by means of a mandrel peel test

NARCIS (Netherlands)

Su, Yibo; de Rooij, Matthias B.; Grouve, Wouter Johannes Bernardus; Warnet, Laurent

2016-01-01

Fastener free metal–carbon fibre reinforced thermoplastic composite hybrid joints show potential for application in aerospace structures. The strength of the metal–thermoplastic composite interface is crucial for the performance of the entire hybrid joint. Optimisation of the interface requires an

Ultrasonic assisted consolidation of commingled thermoplastic/glass fibers rovings

Directory of Open Access Journals (Sweden)

Francesca eLionetto

2015-04-01

Full Text Available Thermoplastic matrix composites are finding new applications in different industrial area thanks to their intrinsic advantages related to environmental compatibility and processability. The approach presented in this work consists in the development of a technology for the simultaneous deposition and consolidation of commingled thermoplastic rovings through to the application of high energy ultrasound. An experimental equipment, integrating both fiber impregnation and ply consolidation in a single process, has been designed and tested. It is made of an ultrasonic welder, whose titanium sonotrode is integrated on a filament winding machine. During winding, the commingled roving is at the same time in contact with the mandrel and the horn. The intermolecular friction generated by ultrasound is able to melt the thermoplastic matrix and impregnate the reinforcement fibers. The heat transfer phenomena occurring during the in situ consolidation were simulated solving by finite element (FE analysis an energy balance accounting for the heat generated by ultrasonic waves and the melting characteristics of the matrix. To this aim, a calorimetric characterization of the thermoplastic matrix has been carried out to obtain the input parameters for the model. The FE analysis has enabled to predict the temperature distribution in the composite during heating and cooling The simulation results have been validated by the measurement of the temperature evolution during ultrasonic consolidation.The reliability of the developed consolidation equipment was proved by producing hoop wound cylinder prototypes using commingled continuous E-glass rovings and Polypropylene (PP filaments. The consolidated composite cylinders are characterized by high mechanical properties, with values comparable with the theoretical ones predicted by the micromechanical analysis.

Statistical analysis of magnetically soft particles in magnetorheological elastomers

Science.gov (United States)

Gundermann, T.; Cremer, P.; Löwen, H.; Menzel, A. M.; Odenbach, S.

2017-04-01

The physical properties of magnetorheological elastomers (MRE) are a complex issue and can be influenced and controlled in many ways, e.g. by applying a magnetic field, by external mechanical stimuli, or by an electric potential. In general, the response of MRE materials to these stimuli is crucially dependent on the distribution of the magnetic particles inside the elastomer. Specific knowledge of the interactions between particles or particle clusters is of high relevance for understanding the macroscopic rheological properties and provides an important input for theoretical calculations. In order to gain a better insight into the correlation between the macroscopic effects and microstructure and to generate a database for theoretical analysis, x-ray micro-computed tomography (X-μCT) investigations as a base for a statistical analysis of the particle configurations were carried out. Different MREs with quantities of 2-15 wt% (0.27-2.3 vol%) of iron powder and different allocations of the particles inside the matrix were prepared. The X-μCT results were edited by an image processing software regarding the geometrical properties of the particles with and without the influence of an external magnetic field. Pair correlation functions for the positions of the particles inside the elastomer were calculated to statistically characterize the distributions of the particles in the samples.

Effect of thermoplastic appliance thickness on initial stress distribution in periodontal ligament

Directory of Open Access Journals (Sweden)

De-Shin Liu

2015-04-01

Full Text Available A numerical investigation into the initial stress distribution induced within the periodontal ligament by thermoplastic appliances with different thicknesses is performed. Based on the plaster model of a 25-year-old male patient, a finite element model of the maxillary lateral incisors and their supporting structures is constructed. In addition, four finite element models of thermoplastic appliances with different thicknesses in the range of 0.5–1.25 mm are also constructed based on the same plaster model. Finite element analysis simulations are performed to examine the effects of the force delivered by the thermoplastic appliances on the stress response of the periodontal ligament during the elastic recovery process. The results show that the stress induced in the periodontal ligament increases with an increasing appliance thickness. For example, the stress triples from 0.0012 to 0.0038 MPa as the appliance thickness is increased from 0.75 to 1.25 mm. The results presented in this study provide a useful insight into as a result of the compressive and tensile stresses induced by thermoplastic appliances of different thicknesses. Moreover, the results enable the periodontal ligament stress levels produced by thermoplastic appliances of different thicknesses to be reliably estimated.

Giant, Voltage-Actuated Deformation of a Dielectric Elastomer under Dead Load

OpenAIRE

Huang, Jiangshui; Li, Tiefeng; Foo, Choon Chiang; Clarke, David R.; Zhu, Jian; Suo, Zhigang

2012-01-01

Far greater voltage-actuated deformation is achievable for a dielectric elastomer under equal-biaxial dead load than under rigid constraint usually employed. Areal strains of 488% are demonstrated. The dead load suppresses electric breakdown, enabling the elastomer to survive the snap-through electromechanical instability. The breakdown voltage is found to increase with the voltage ramp rate. A nonlinear model for viscoelastic dielectric elastomers is developed and shown to be consistent with...

Two-way actuation behavior of shape memory polymer/elastomer core/shell composites

International Nuclear Information System (INIS)

Kang, Tae-Hyung; Lee, Jeong-Min; Yu, Woong-Ryeol; Youk, Ji Ho; Ryu, Hee Wook

2012-01-01

Semi-crystalline shape memory polymers (SMPs) show net two-way shape memory (2W-SM) behavior under constant stresses by the recoverable creep strain upon heating and stress-induced crystallization under the application of creep stress upon cooling. The applied constant stress is the key factor in this 2W-SM behavior. A core/shell structure is manufactured for the purpose of imparting a constant stress upon SMPs. An SMP in film or fiber form is dipped into a solution of an elastomer, photoinitiator, and curing agent and then dried out. After this dip coating process is repeatedly carried out, the SMP/elastomer core/shell composite is deformed into a temporary shape after being heated up above the transition temperature of the SMP. Under constant strain conditions, the composite is cooled down, after which the shell elastomer is cured using ultraviolet light. Then, the SMP/elastomer core/shell composite extends and contracts upon cooling and heating, respectively, without any external load. This cyclic deformation behavior is characterized, demonstrating that the current method offers a simple macroscopic processing technique to manufacture 2W-SM polymer composites. (paper)

Training and qualification of the auxiliaries of operation using the methodology On the Job Training (OJT) and Task Performance Evaluation (TPE); Formacion y culificacion de los auxiliares de operacion mediante la metodologia On the Job Training (OJT) y Task Performance Evaluation (TPE)

Energy Technology Data Exchange (ETDEWEB)

Martinez Casado, J.

2015-07-01

On the Job Training (OJT) and Task Performance Evaluation (TPE). This plan has been developed and put in practice entirely, by a group of experienced auxiliary operation that have distinguished themselves by their professionalism, knowledge of the work, technical expertise and commitment to nuclear safety. (Author)

Processing of thermoplastic polymers using reactive solvents

NARCIS (Netherlands)

Meijer, H.E.H.; Venderbosch, R.W.; Goossens, J.G.P.; Lemstra, P.J.

1996-01-01

The use of reactive solvents offers an interesting and flexible route to extent the processing characteristics of thermoplastic polymers beyond their existing limits. This holds for both intractable and tractable polymers. The first mainly applies for amorphous high-Tg polymers where processing may

Building Block Approach' for Structural Analysis of Thermoplastic Composite Components for Automotive Applications

Science.gov (United States)

Carello, M.; Amirth, N.; Airale, A. G.; Monti, M.; Romeo, A.

2017-12-01

Advanced thermoplastic prepreg composite materials stand out with regard to their ability to allow complex designs with high specific strength and stiffness. This makes them an excellent choice for lightweight automotive components to reduce mass and increase fuel efficiency, while maintaining the functionality of traditional thermosetting prepreg (and mechanical characteristics) and with a production cycle time and recyclability suited to mass production manufacturing. Currently, the aerospace and automotive sectors struggle to carry out accurate Finite Elements (FE) component analyses and in some cases are unable to validate the obtained results. In this study, structural Finite Elements Analysis (FEA) has been done on a thermoplastic fiber reinforced component designed and manufactured through an integrated injection molding process, which consists in thermoforming the prepreg laminate and overmolding the other parts. This process is usually referred to as hybrid molding, and has the provision to reinforce the zones subjected to additional stresses with thermoformed themoplastic prepreg as required and overmolded with a shortfiber thermoplastic resin in single process. This paper aims to establish an accurate predictive model on a rational basis and an innovative methodology for the structural analysis of thermoplastic composite components by comparison with the experimental tests results.

Optimization Techniques for Improving the Performance of Silicone-Based Dielectric Elastomers

DEFF Research Database (Denmark)

Skov, Anne Ladegaard; Yu, Liyun

2017-01-01

the electro-mechanical performance of dielectric elastomers are highlighted. Various optimization methods for improved energy transduction are investigated and discussed, with special emphasis placed on the promise each method holds. The compositing and blending of elastomers are shown to be simple, versatile...... methods that can solve a number of optimization issues. More complicated methods, involving chemical modification of the silicone backbone as well as controlling the network structure for improved mechanical properties, are shown to solve yet more issues. From the analysis, it is obvious...... that there is not a single optimization technique that will lead to the universal optimization of dielectric elastomer films, though each method may lead to elastomers with certain features, and thus certain potentials....

New reusable elastomer electrodes for assessing body composition

International Nuclear Information System (INIS)

Moreno, M-V; Chaset, L; Bittner, P A; Barthod, C; Passard, M

2013-01-01

The development of telemedicine requires finding solutions of reusable electrodes for use in patients' homes. The objective of this study is to evaluate the relevance of reusable elastomer electrodes for measuring body composition. We measured a population of healthy Caucasian (n = 17). A measurement was made with a reference device, the Xitron®, associated with AgCl Gel electrodes (Gel) and another measurement with a multifrequency impedancemeter Z-Metrix® associated with reusable elastomer electrodes (Elast). We obtained a low variability with an average error of repeatability of 0.39% for Re and 0.32% for Rinf. There is a non significantly difference (P T-test > 0.1) about 200 ml between extracellular water Ve measured with Gel and Elast in supine and in standing position. For total body water Vt, we note a non significantly difference (P T-test > 0.1) about 100 ml and 2.2 1 respectively in supine and standing position. The results give low dispersion, with R 2 superior to 0.90, with a 1.5% maximal error between Gel and Elast on Ve in standing position. It looks possible, taking a few precautions, using elastomer electrodes for assessing body composition.

Toughening elastomers with sacrificial bonds and watching them break

Science.gov (United States)

Creton, Costantino

2014-03-01

Most unfilled elastomers are relatively brittle, in particular when the average molecular weight between crosslinks is lower than the average molecular weight between entanglements. We created a new class of tough elastomers by introducing isotropically prestretched chains inside ordinary acrylic elastomers by successive swelling and polymerization steps. These new materials combine a high entanglement density with a densely crosslinked structure reaching elastic moduli of 4 MPa and fracture strength of 25 MPa. The highly prestretched chains are the minority in the material and can break in the bulk of the material before catastrophic failure occurs, increasing the toughness of the material by two orders of magnitude up to 5 kJ/m2. To investigate the details of the toughening mechanism we introduced specific sacrificial dioxetane bonds in the prestretched chains that emit light when they break. In uniaxial extension cyclic experiments, we checked that the light emission corresponded exactly and quantitatively to the energy dissipation in each cycle demonstrating that short chains break first and long chains later. We then watched crack propagation in notched samples and mapped spatially the location of bond breakage ahead of the crack tip before and during propagation. This new toughening mechanism for elastomers creates superentangled rubbers and is ideally suited to overcome the trade-off between toughness and stiffness of ordinary elastomers. We gratefully acknowledge funding from DSM Ahead

Super soft silicone elastomers with high dielectric permittivity

DEFF Research Database (Denmark)

Madsen, Frederikke Bahrt; Yu, Liyun; Hvilsted, Søren

2015-01-01

Dielectric elastomers (DEs) have many favourable properties. The obstacle of high driving voltages, however, limits the commercial viability of the technology at present. Driving voltage can be lowered by decreasing the Young’s modulus and increasing the dielectric permittivity of silicone...... elastomers. A decrease in Young’s modulus, however, is often accompanied by the loss of mechanical stability and thereby the lifetime of the DE. New soft elastomer matrices with high dielectric permittivity and low Young’s modulus, with no loss of mechanical stability, were prepared by two different...... approaches using chloropropyl-functional silicone polymers. The first approach was based on synthesised chloropropyl-functional copolymers that were cross-linkable and thereby formed the basis of new silicone networks with high dielectric permittivity (e.g. a 43% increase). These networks were soft without...

Silicone elastomers with superior softness and dielectric properties

DEFF Research Database (Denmark)

Yu, Liyun; Madsen, Frederikke Bahrt; Zakaria, Shamsul Bin

Dielectric elastomers (DEs) change their shape and size under a high voltage or reversibly generate a high voltage when deformed. The obstacle of high driving voltages, however, limits the commercial viability of the technology at present. Driving voltage can be lowered by decreasing the Young......’s modulus and increasing the dielectric permittivity of silicone elastomers. One such prominent method of modifying the properties is by adding suitable additives. [1] The major drawbacks for adding solid fillers are agglomeration and increasing stiffness which is often accompanied by the decrease...... were determined by NMR and morphology structures were investigated by optical microscopy. The resulting elastomers were evaluated with respect to their dielectric permittivity, tear and tensile strengths, as well as electrical breakdown.The breakdown strength increased at low amounts of additives...

Theory Of Dewetting In A Filled Elastomer Under Stress

Science.gov (United States)

Peng, Steven T. J.

1993-01-01

Report presents theoretical study of dewetting between elastomeric binder and filler particles of highly filled elastomer under multiaxial tension and resulting dilatation of elastomer. Study directed toward understanding and predicting nonlinear stress-vs.-strain behavior of filled elastomeric rocket propellant, also applicable to rubber in highly loaded tire or in damping pad.

Numerical analysis of laminated elastomer by FEM

International Nuclear Information System (INIS)

Mazda, T.; Shiojiri, H.

1993-01-01

A Computer code based on mixed finite element method was developed for three dimensional large strain analyses of laminated elastomers including nonlinear bulk stress vs. bulk strain relationships. The adopted element is the variable node element with maximum node numbers of 27 for displacements and 4 for pressures. At first, the displacements and pressures were calculated by the code using single element under various loading conditions. The results were compared with theoretical solutions and the both results' exactly coincided with each other. Next, the analyses of laminated elastomers subjected to axial loadings were conducted using both the new code and ABAQUS code, and the results were compared with the test results. The agreement of the results of the present code were better than ABAQUS code mainly due to the capability of handling wider range of material properties. Lastly, the shearing tests of laminated elastomers were simulated by the new code. The results were shown to be in good agreement with the test results. (author)

Interfacial Properties of EXXPRO(TM) and General Purpose Elastomers

Science.gov (United States)

Zhang, Y.; Rafailovich, M.; Sokolov, Jon; Qu, S.; Ge, S.; Ngyuen, D.; Li, Z.; Peiffer, D.; Song, L.; Dias, J. A.; McElrath, K. O.

1998-03-01

EXXPRO(Trademark) elastomers are used for tires and many other applications. This elastomer (denoted as BIMS) is a random copolymer of p-methylstyrene (MS) and polyisobutylene (I) with varying degrees of PMS content and bromination (B) on the p-methyl group. BIMS is impermeable to gases, and has good heat, ozone and flex resistance. Very often general purpose elastomers are blended with BIMS. The interfacial width between polybutadiene and BIMS is a sensitive function of the Br level and PMS content. By neutron reflectivity (NR), we studied the dynamics of interface formation as a function of time and temperature for BIMS with varying degrees of PMS and Br. We found that in addition to the bulk parameters, the total film thickness and the proximity of an interactive surface can affect the interfacial interaction rates. The interfacial properties can also be modified by inclusion of particles, such as carbon black (a filler component in tire rubbers). Results will be presented on the relation between the interfacial width as measured by NR and compatibilization studies via AFM and LFM.

Compatibility of elastomers in palm biodiesel

Energy Technology Data Exchange (ETDEWEB)

Haseeb, A.S.M.A.; Masjuki, H.H.; Siang, C.T.; Fazal, M.A. [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2010-10-15

In recent time, environmental awareness and concern over the rapid exhaustion of fossil fuels have led to an increased popularity of biodiesel as an alternative fuel for automobiles. However, there are concerns over enhanced degradation of automotive materials in biodiesel. The present study aims to investigate the impact of palm biodiesel on the degradation behavior of elastomers such as nitrile rubber (NBR), polychloroprene, and fluoro-viton A. Static immersion tests in B0 (diesel), B10 (10% biodiesel in diesel), B100 (biodiesel) were carried out at room temperature (25 C) and at 50 C for 500 h. At the end of immersion test, degradation behavior was investigated by measuring mass, volume, hardness as well as tensile strength and elongation. The exposed elastomer surface was studied by scanning electron microscopy (SEM). Fourier Transform Infrared (FTIR) spectroscopy was carried out to identify the chemical and structural changes. Results showed that the extent of degradation was higher for both polychloroprene and NBR while fluoro-viton exhibited good resistance to degradation and was least attacked. (author)

Modeling of Magnetostriction of Soft Elastomer

International Nuclear Information System (INIS)

Petr, Andriushchenko; Leonid, Afremov; Mariya, Chernova

2014-01-01

Small magnetic particles placed in a relatively soft polymer (with elastic modulus E ∼ 10 ÷ 100 kPa) are magnetically soft elastomers. The external magnetic field acts on each particle which leads to microscopic deformation of the material and consequently to changing of its shape – magnetostriction. For purposes of studying of magnetostriction the model of movable cellular automata (MCA), in which a real heterogeneous material is an ensemble of interacting elements of finite size – automata, is used. It's supposed to be that the motion of each automata can be described by Newton's Second law. The force acting on the i-th automata consists of the following components: volume-dependent force acting on the automata i which is caused by pressure from the surrounding automata; force of an external magnetic field acting on the i-th automata with some magnetic moment; and normal and tangential interaction force between a pair of i and j automata. This approach was used for modeling of magnetostriction elastomer

Degradation of physical properties of different elastomers upon exposure to palm biodiesel

International Nuclear Information System (INIS)

Haseeb, A.S.M.A.; Jun, T.S.; Fazal, M.A.; Masjuki, H.H.

2011-01-01

Biodiesel, as an alternative fuel, is gradually receiving more popularity for use in internal combustion engines. However questions continue to arise with regard to its compatibility with elastomeric materials. The present work aims to investigate the comparative degradation of physical properties for different elastomers [e.g. ethylene propylene diene monomer (EPDM), silicone rubber (SR), polychloroprene (CR), polytetrafluroethylene (PTFE) and nitrile rubber (NBR)] upon exposure to diesel and palm biodiesel. Static immersion tests in B0(diesel), B10 (10% biodiesel in diesel), B20, B50 and B100(biodiesel) were carried out at room temperature (25 o C) for 1000 h. Different physical properties like, changes in weight and volume, hardness and tensile strength were measured at every 250 h of immersion time. Compositional changes in biodiesel due to exposure of different elastomers were investigated by Gas chromatography mass spectroscopy (GCMS). The overall sequence of compatible elastomers in palm biodiesel is found to be PTFE > SR > NBR > EPDM > CR. -- Research highlights: → Biodiesel and its blends swelled polychloroprene (CR) and nitrile rubber (NBR) to a greater extent than did diesel. → Although PTFE seems to be the most compatible elastomer among those tested, it undergoes a slight reduction of main constituents. →The overall sequence of compatible elastomers in palm biodiesel is PTFE > SR > NBR > EPDM > CR.

Polymer compositions and methods

Energy Technology Data Exchange (ETDEWEB)

Allen, Scott D.; Willkomm, Wayne R.

2018-02-06

The present invention encompasses polyurethane compositions comprising aliphatic polycarbonate chains. In one aspect, the present invention encompasses polyurethane foams, thermoplastics and elastomers derived from aliphatic polycarbonate polyols and polyisocyanates wherein the polyol chains contain a primary repeating unit having a structure: ##STR00001## In another aspect, the invention provides articles comprising the inventive foam and elastomer compositions as well as methods of making such compositions.

A small biomimetic quadruped robot driven by multistacked dielectric elastomer actuators

Science.gov (United States)

Nguyen, Canh Toan; Phung, Hoa; Dat Nguyen, Tien; Lee, Choonghan; Kim, Uikyum; Lee, Donghyouk; Moon, Hyungpil; Koo, Jachoon; Nam, Jae-do; Ryeol Choi, Hyouk

2014-06-01

A kind of dielectric elastomer (DE) material, called ‘synthetic elastomer’, has been developed based on acrylonitrile butadiene rubber (NBR) to be used as a dielectric elastomer actuator (DEA). By stacking single layers of synthetic elastomer, a linear actuator, called a multistacked actuator, is produced, and used by mechatronic and robotic systems to generate linear motion. In this paper, we demonstrate the application of the multistacked dielectric elastomer actuator in a biomimetic legged robot. A miniature robot driven by a biomimetic actuation system with four 2-DOF (two-degree-of-freedom) legged mechanisms is realized. Based on the experimental results, we evaluate the performance of the proposed robot and validate the feasibility of the multistacked actuator in a locomotion system as a replacement for conventional actuators.

A small biomimetic quadruped robot driven by multistacked dielectric elastomer actuators

International Nuclear Information System (INIS)

Nguyen, Canh Toan; Phung, Hoa; Nguyen, Tien Dat; Lee, Choonghan; Kim, Uikyum; Lee, Donghyouk; Moon, Hyungpil; Koo, Jachoon; Choi, Hyouk Ryeol; Nam, Jae-do

2014-01-01

A kind of dielectric elastomer (DE) material, called ‘synthetic elastomer’, has been developed based on acrylonitrile butadiene rubber (NBR) to be used as a dielectric elastomer actuator (DEA). By stacking single layers of synthetic elastomer, a linear actuator, called a multistacked actuator, is produced, and used by mechatronic and robotic systems to generate linear motion. In this paper, we demonstrate the application of the multistacked dielectric elastomer actuator in a biomimetic legged robot. A miniature robot driven by a biomimetic actuation system with four 2-DOF (two-degree-of-freedom) legged mechanisms is realized. Based on the experimental results, we evaluate the performance of the proposed robot and validate the feasibility of the multistacked actuator in a locomotion system as a replacement for conventional actuators. (paper)

Wood thermoplastic composites

Science.gov (United States)

Daniel F. Caulfield; Craig Clemons; Rodney E. Jacobson; Roger M. Rowell

2005-01-01

The term “wood-plastic composites” refers to any number of composites that contain wood (of any form) and either thermoset or thermoplastic polymers. Thermosets or thermoset polymers are plastics that, once cured, cannot be remelted by heating. These include cured resins, such as epoxies and phenolics, plastics with which the forest products industry is most familiar (...

Training programme impact on thermoplastic immobilization for head and neck radiation therapy

International Nuclear Information System (INIS)

Outhwaite, Julie-Anne; McDowall, W. Robert; Marquart, Louise; Rattray, Gregory; Fielding, Andrew; Hargrave, Catriona

2013-01-01

Purpose: To determine whether uniform guidelines and training in the stabilization and formation of thermoplastic shells can improve the reproducibility of set-up for Head and Neck cancer patients. Methods and materials: Image based measurements of the planning and treatment positions for 35 head and neck cancer patients undergoing radical radiotherapy were analysed to provide a baseline of the reproducibility of thermoplastic immobilization. Radiation therapists (RT) were surveyed to establish a perception of their confidence in thermoplastic procedures. An evidence based staff training programme was created and implemented. Set-up reproduction and staff perception were reviewed to measure the impact of the training programme. Results: The mean (SD) 3D vectors of anatomical displacement, measured on the patient images, improved from 4.64 (2.03) for the baseline group compared to 3.02 (1.65) following training (p < 0.01). The proportion of 3D displacements of patient data exceeding 5 mm 3D vector was decreased from 37.1% to 5.7% (p < 0.001) and the 3 mm vector from 85.7% to 42.9% (p < 0.001). The post-training survey scores demonstrated improved confidence in reproducibility of set-up for head and neck patients. Conclusion: The Thermoplastic Shells Training Program has been found to improve the treatment reproducibility for head and neck radiation therapy patients. Uniform guidelines have increased RT confidence in thermoplastic procedures.

Fracture studies of poly(propylene)/elastomer blend with β-form nucleating agent

International Nuclear Information System (INIS)

Bai Hongwei; Wang Yong; Zhang Danli; Xiao Chengquan; Song Bo; Li Yanli; Han Liang

2009-01-01

Poly(propylene)/elastomer blends with β-form nucleating agent (β-NA) aryl amides compound (TMB-5) were prepared. The effects of β-NA on crystallization, melting behaviors and elastomer morphologies of PP/elastomer blends were studied through polarization optical microscope (POM), differential scanning calorimetry (DSC) and scanning electronic microscope (SEM). The fracture behaviors, including notched Izod impact fracture and single-edge notched tensile (SENT) fracture, were comparatively studied to establish the role of NA in improving the fracture toughness of PP/elastomer blends. Our results showed that the presence of β-NA leads to determinable β-PP formation in the blends, and as a consequence the fracture toughness of the blend is improved dramatically. Compared with notched Izod impact testing, which can efficiently characterize the fracture toughness of the blends only at lower elastomer content, SENT testing provides more detail of fracture behavior in all the compositions. Furthermore, SENT test shows that the significant improvement in fracture toughness of PP/elastomer/β-NA is contributed to the simultaneous enhancement of crack initiation energy and crack propagation energy, but largely dominated by crack propagation stage.

Stress measurements of planar dielectric elastomer actuators

Energy Technology Data Exchange (ETDEWEB)

Osmani, Bekim; Aeby, Elise A.; Müller, Bert [Biomaterials Science Center, University of Basel, Gewerbestrasse 14, 4123 Allschwil (Switzerland)

2016-05-15

Dielectric elastomer actuator (DEA) micro- and nano-structures are referred to artificial muscles because of their specific continuous power and adequate time response. The bending measurement of an asymmetric, planar DEA is described. The asymmetric cantilevers consist of 1 or 5 μm-thin DEAs deposited on polyethylene naphthalate (PEN) substrates 16, 25, 38, or 50 μm thick. The application of a voltage to the DEA electrodes generates an electrostatic pressure in the sandwiched silicone elastomer layer, which causes the underlying PEN substrate to bend. Optical beam deflection enables the detection of the bending angle vs. applied voltage. Bending radii as large as 850 m were reproducibly detected. DEA tests with electric fields of up to 80 V/μm showed limitations in electrode’s conductivity and structure failures. The actuation measurement is essential for the quantitative characterization of nanometer-thin, low-voltage, single- and multi-layer DEAs, as foreseen for artificial sphincters to efficiently treat severe urinary and fecal incontinence.

Stress measurements of planar dielectric elastomer actuators

International Nuclear Information System (INIS)

Osmani, Bekim; Aeby, Elise A.; Müller, Bert

2016-01-01

Dielectric elastomer actuator (DEA) micro- and nano-structures are referred to artificial muscles because of their specific continuous power and adequate time response. The bending measurement of an asymmetric, planar DEA is described. The asymmetric cantilevers consist of 1 or 5 μm-thin DEAs deposited on polyethylene naphthalate (PEN) substrates 16, 25, 38, or 50 μm thick. The application of a voltage to the DEA electrodes generates an electrostatic pressure in the sandwiched silicone elastomer layer, which causes the underlying PEN substrate to bend. Optical beam deflection enables the detection of the bending angle vs. applied voltage. Bending radii as large as 850 m were reproducibly detected. DEA tests with electric fields of up to 80 V/μm showed limitations in electrode’s conductivity and structure failures. The actuation measurement is essential for the quantitative characterization of nanometer-thin, low-voltage, single- and multi-layer DEAs, as foreseen for artificial sphincters to efficiently treat severe urinary and fecal incontinence.

Investigation on the performance of a viscoelastic dielectric elastomer membrane generator.

Science.gov (United States)

Zhou, Jianyou; Jiang, Liying; Khayat, Roger E

2015-04-21

Dielectric elastomer generators (DEGs), as a recent transduction technology, harvest electrical energy by scavenging mechanical energy from diverse sources. Their performance is affected by various material properties and failure modes of the dielectric elastomers. This work presents a theoretical analysis on the performance of a dielectric elastomer membrane generator under equi-biaxial loading conditions. By comparing our simulation results with the experimental observations existing in the literature, this work considers the fatigue life of DE-based devices under cyclic loading for the first time. From the simulation results, it is concluded that the efficiency of the DEG can be improved by raising the deforming rate and the prescribed maximum stretch ratio, and applying an appropriate bias voltage. However, the fatigue life expectancy compromises the efficiency improvement of the DEG. With the consideration of the fatigue life, applying an appropriate bias voltage appears to be a more desirable way to improve the DEG performance. The general framework developed in this work is expected to provide an increased understanding on the energy harvesting mechanisms of the DEGs and benefit their optimal design.

Viscous and thermal modelling of thermoplastic composites forming process

Science.gov (United States)

Guzman, Eduardo; Liang, Biao; Hamila, Nahiene; Boisse, Philippe

2016-10-01

Thermoforming thermoplastic prepregs is a fast manufacturing process. It is suitable for automotive composite parts manufacturing. The simulation of thermoplastic prepreg forming is achieved by alternate thermal and mechanical analyses. The thermal properties are obtained from a mesoscopic analysis and a homogenization procedure. The forming simulation is based on a viscous-hyperelastic approach. The thermal simulations define the coefficients of the mechanical model that depend on the temperature. The forming simulations modify the boundary conditions and the internal geometry of the thermal analyses. The comparison of the simulation with an experimental thermoforming of a part representative of automotive applications shows the efficiency of the approach.

Finite element analysis and validation of dielectric elastomer actuators used for active origami

International Nuclear Information System (INIS)

McGough, Kevin; Ahmed, Saad; Frecker, Mary; Ounaies, Zoubeida

2014-01-01

The field of active origami explores the incorporation of active materials into origami-inspired structures in order to serve as a means of actuation. Active origami-inspired structures capable of folding into complex three-dimensional (3D) shapes have the potential to be lightweight and versatile compared to traditional methods of actuation. This paper details the finite element analysis and experimental validation of unimorph actuators. Actuators are fabricated by adhering layers of electroded dielectric elastomer (3M VHB F9473PC) onto a passive substrate layer (3M Magic Scotch Tape). Finite element analysis of the actuators simulates the electromechanical coupling of the dielectric elastomer under an applied voltage by applying pressures to the surfaces of the dielectric elastomer where the compliant electrode (conductive carbon grease) is present. 3D finite element analysis of the bending actuators shows that applying contact boundary conditions to the electroded region of the active and passive layers provides better agreement to experimental data compared to modeling the entire actuator as continuous. To improve the applicability of dielectric elastomer-based actuators for active origami-inspired structures, folding actuators are developed by taking advantage of localized deformation caused by a passive layer with non-uniform thickness. Two-dimensional analysis of the folding actuators shows that agreement to experimental data diminishes as localized deformation increases. Limitations of using pressures to approximate the electromechanical coupling of the dielectric elastomer under an applied electric field and additional modeling considerations are also discussed. (paper)

Mechanical properties: wood lumber versus plastic lumber and thermoplastic composites

Directory of Open Access Journals (Sweden)

Bernardo Zandomenico Dias

Full Text Available Abstract Plastic lumber and thermoplastic composites are sold as alternatives to wood products. However, many technical standards and scientific studies state that the two materials cannot be considered to have the same structural behaviour and strength. Moreover, there are many compositions of thermoplastic-based products and plenty of wood species. How different are their mechanical properties? This study compares the modulus of elasticity and the flexural, compressive, tensile and shear strengths of such materials, as well as the materials' specific mechanical properties. It analyses the properties of wood from the coniferae and dicotyledon species and those of commercialized and experimental thermoplastic-based product formulations. The data were collected from books, scientific papers and manufacturers' websites and technical data sheets, and subsequently compiled and presented in Ashby plots and bar graphs. The high values of the compressive strength and specific compressive and tensile strengths perpendicular to the grain (width direction shown by the experimental thermoplastic composites compared to wood reveal their great potential for use in compressed elements and in functions where components are compressed or tensioned perpendicularly to the grain. However, the low specific flexural modulus and high density of thermoplastic materials limit their usage in certain civil engineering and building applications.

Friction and bending in thermoplastic composites forming processes

NARCIS (Netherlands)

Sachs, Ulrich

2014-01-01

With the demand for better fuel economy in the aerospace and automotive industries, lightweight polymer matrix composites became an attractive alternative for metal structures. Despite the inherently higher toughness and impact damage resistance of thermoplastics, thermoset matrix composites are

Accuracy of Implants Placed with Surgical Guides: Thermoplastic Versus 3D Printed.

Science.gov (United States)

Bell, Caitlyn K; Sahl, Erik F; Kim, Yoon Jeong; Rice, Dwight D

This study was conducted to evaluate the accuracy of implants placed using two different guided implant surgery materials: thermoplastic versus three-dimensionally (3D) printed. A cone beam computed tomography (CBCT) scan previously obtained and selected for single-tooth implant replacement was converted into a Digital Imaging and Communications in Medicine (DICOM) file. All models were planned and exported for printing using BlueSkyBio Plan Software with the DICOM files. A total of 20 3D-printed mandibular quadrant jaws replicating the CBCT were printed by Right Choice Milling, as was the control model to accept the control implant. Previously, 10 thermoplastic and 10 3D-printed surgical guides had been made by the same lab technician at Right Choice Milling. One Nobel Biocare implant with a trilobe connection was placed per guide and replica jaw model pair. Implants were placed using the thermoplastic and 3D-printed surgical guides, representing the two test groups, following the Nobel Biocare guided surgical protocol. A total of 21 CBCT scans were then taken, one for the control implant and one for each test implant. The CBCT volume was converted to a DICOM file and transferred to Invivo5 software version 5.4 (Anatomage). The DICOM file of each test implant was superimposed over the DICOM file of the control. The deviation of the head of the implant, the deviation of the apex of the implant, and the angle of deviation were evaluated from measurements on the superimposition of the control and test implants. Mann-Whitney U test was used to test the null hypotheses at α = .05 and a confidence interval of 95%. Descriptive statistics were used for the average ± standard deviation. The implants placed with the thermoplastic surgical guides showed an average of 3.40 degrees of angular deviation compared to 2.36 degrees for implants placed with the 3D-printed surgical guides (P = .143). The implants placed with the thermoplastic surgical guides showed an average of 1

Manufacturing of a REBCO racetrack coil using thermoplastic resin aiming at Maglev application

Science.gov (United States)

Mizuno, Katsutoshi; Ogata, Masafumi; Hasegawa, Hitoshi

2015-11-01

The REBCO coated conductor is a promising technology for the Maglev application in terms of its high critical temperature. The operating temperature of the on-board magnets can be around 40-50 K with the coated conductor. The REBCO coils are cooled by cryocoolers directly, and hence the thermal design of the REBCO coils significantly changes from that of LTS coils. We have developed a novel REBCO coil structure using thermoplastic resin. The coil is not impregnated and the thermoplastic resin is used to bond the coil winding and the heat transfer members, e.g. copper and aluminum plates. The viscosity of the thermoplastic resin is high enough for the thermoplastic resin not to permeate between the turns in the coil. Therefore, the thermal stress does not occur and the risk of degradation is removed. This paper contains the following three topics. First, the thermal resistance of the thermoplastic resin was measured at cryogenic temperature. Then, a small round REBCO coil was experimentally produced. It has been confirmed that the thermoplastic resin does not cause the degradation and, the adhesion between the coil winding and copper plates withstands the thermal stress. Finally, we successfully produced a full-scale racetrack REBCO coil applying the coil structure with the thermoplastic resin.

Sterilizing radiation effects on selected polymers

International Nuclear Information System (INIS)

Skiens, W.E.

1979-03-01

The mechanism of radiation effects and their industrial applications are discussed for the following classes of polymers: thermoplastics, thermosets, elastomers, films and fibers, and adhesives/coatings/potting compounds. 35 references, 3 tables

Compression molding of chopped woven thermoplastic composite flakes

NARCIS (Netherlands)

Abdul Rasheed, Mohammed Iqbal

2016-01-01

Continuous fiber reinforced composites with high-performance thermoplastic polymer matrices have an enormous potential in terms of performance, production rate, cost efficiency and recyclability. The use of this relatively new class of materials by the aerospace and automotive industry has been

Continuous Natural Fiber Reinforced Thermoplastic Composites by Fiber Surface Modification

Directory of Open Access Journals (Sweden)

Patcharat Wongsriraksa

2013-01-01

Full Text Available Continuous natural fiber reinforced thermoplastic materials are expected to replace inorganic fiber reinforced thermosetting materials. However, in the process of fabricating the composite, it is difficult to impregnate the thermoplastic resin into reinforcement fiber because of the high melt viscosity. Therefore, intermediate material, which allows high impregnation during molding, has been investigated for fabricating continuous fiber reinforced thermoplastic composite by aligning resin fiber alongside reinforcing fiber with braiding technique. This intermediate material has been called “microbraid yarn (MBY.” Moreover, it is well known that the interfacial properties between natural fiber and resin are low; therefore, surface treatment on continuous natural fiber was performed by using polyurethane (PU and flexible epoxy (FLEX to improve the interfacial properties. The effect of surface treatment on the mechanical properties of continuous natural fiber reinforced thermoplastic composites was examined. From these results, it was suggested that surface treatment by PU with low content could produce composites with better mechanical properties.

Bending behavior of thermoplastic composite sheets viscoelasticity and temperature dependency in the draping process

CERN Document Server

Ropers, Steffen

2017-01-01

Within the scope of this work, Steffen Ropers evaluates the viscoelastic and temperature-dependent nature of the bending behavior of thermoplastic composite sheets in order to further enhance the predictability of the draping simulation. This simulation is a useful tool for the development of robust large scale processes for continuously fiber-reinforced polymers (CFRP). The bending behavior thereby largely influences the size and position of wrinkles, which are one of the most common processing defects for continuously fiber-reinforced parts. Thus, a better understanding of the bending behavior of thermoplastic composite sheets as well as an appropriate testing method along with corresponding material models contribute to a wide-spread application of CFRPs in large scale production. Contents Thermoplastic Prepregs Draping Simulation of Thermoplastic Prepregs Bending Characterization of Textile Composites Modeling of Bending Behavior Target Groups Researchers and students in the field of polymer, lightweight,...

Electromechanical performance analysis of inflated dielectric elastomer membrane for micro pump applications

Science.gov (United States)

Saini, Abhishek; Ahmad, Dilshad; Patra, Karali

2016-04-01

Dielectric elastomers have received a great deal of attention recently as potential materials for many new types of sensors, actuators and future energy generators. When subjected to high electric field, dielectric elastomer membrane sandwiched between compliant electrodes undergoes large deformation with a fast response speed. Moreover, dielectric elastomers have high specific energy density, toughness, flexibility and shape processability. Therefore, dielectric elastomer membranes have gained importance to be applied as micro pumps for microfluidics and biomedical applications. This work intends to extend the electromechanical performance analysis of inflated dielectric elastomer membranes to be applied as micro pumps. Mechanical burst test and cyclic tests were performed to investigate the mechanical breakdown and hysteresis loss of the dielectric membrane, respectively. Varying high electric field was applied on the inflated membrane under different static pressure to determine the electromechanical behavior and nonplanar actuation of the membrane. These tests were repeated for membranes with different pre-stretch values. Results show that pre-stretching improves the electromechanical performance of the inflated membrane. The present work will help to select suitable parameters for designing micro pumps using dielectric elastomer membrane. However this material lacks durability in operation.This issue also needs to be investigated further for realizing practical micro pumps.

Use of elastomers in regenerative braking systems

Science.gov (United States)

The storage of potential energy as strain energy in elastomers was investigated. The evolution of the preferred stressing scheme is described, and test results on full-size elastomeric energy storage units sized for an automotive regenerative braking system application are presented. The need for elastomeric material improvements is also discussed.

Monitoring diver kinematics with dielectric elastomer sensors

Science.gov (United States)

Walker, Christopher R.; Anderson, Iain A.

2017-04-01

Diving, initially motivated for food purposes, is crucial to the oil and gas industry, search and rescue, and is even done recreationally by millions of people. There is a growing need however, to monitor the health and activity of divers. The Divers Alert Network has reported on average 90 fatalities per year since 1980. Furthermore an estimated 1000 divers require recompression treatment for dive-related injuries every year. One means of monitoring diver activity is to integrate strain sensors into a wetsuit. This would provide kinematic information on the diver potentially improving buoyancy control assessment, providing a platform for gesture communication, detecting panic attacks and monitoring diver fatigue. To explore diver kinematic monitoring we have coupled dielectric elastomer sensors to a wetsuit worn by the pilot of a human-powered wet submarine. This provided a unique platform to test the performance and accuracy of dielectric elastomer strain sensors in an underwater application. The aim of this study was to assess the ability of strain sensors to monitor the kinematics of a diver. This study was in collaboration with the University of Auckland's human-powered submarine team, Team Taniwha. The pilot, completely encapsulated in a hull, pedals to propel the submarine forward. Therefore this study focused on leg motion as that is the primary motion of the submarine pilot. Four carbon-filled silicone dielectric elastomer sensors were fabricated and coupled to the pilot's wetsuit. The first two sensors were attached over the knee joints, with the remaining two attached between the pelvis and thigh. The goal was to accurately measure leg joint angles thereby determining the position of each leg relative to the hip. A floating data acquisition unit monitored the sensors and transmitted data packets to a nearby computer for real-time processing. A GoPro Hero 4 silver edition was used to capture the experiments and provide a means of post-validation. The

Conductive Elastomers for Stretchable Electronics, Sensors and Energy Harvesters

Directory of Open Access Journals (Sweden)

Jin-Seo Noh

2016-04-01

Full Text Available There have been a wide variety of efforts to develop conductive elastomers that satisfy both mechanical stretchability and electrical conductivity, as a response to growing demands on stretchable and wearable devices. This article reviews the important progress in conductive elastomers made in three application fields of stretchable technology: stretchable electronics, stretchable sensors, and stretchable energy harvesters. Diverse combinations of insulating elastomers and non-stretchable conductive materials have been studied to realize optimal conductive elastomers. It is noted that similar material combinations and similar structures have often been employed in different fields of application. In terms of stretchability, cyclic operation, and overall performance, fields such as stretchable conductors and stretchable strain/pressure sensors have achieved great advancement, whereas other fields like stretchable memories and stretchable thermoelectric energy harvesting are in their infancy. It is worth mentioning that there are still obstacles to overcome for the further progress of stretchable technology in the respective fields, which include the simplification of material combination and device structure, securement of reproducibility and reliability, and the establishment of easy fabrication techniques. Through this review article, both the progress and obstacles associated with the respective stretchable technologies will be understood more clearly.

Dispersion of repolarization in canine ventricle and the electrocardiographic T wave: Tp-e interval does not reflect transmural dispersion

NARCIS (Netherlands)

Opthof, Tobias; Coronel, Ruben; Wilms-Schopman, Francien J. G.; Plotnikov, Alexei N.; Shlapakova, Iryna N.; Danilo, Peter; Rosen, Michael R.; Janse, Michiel J.

2007-01-01

BACKGROUND: The concept that the interval between the peak (T(peak)) and the end (T(end)) of the T wave (T(p-e)) is a measure of transmural dispersion of repolarization time is widely accepted but has not been tested rigorously by transmural mapping of the intact heart. OBJECTIVES: The purpose of

Diagnostics of ETL TPE-1 plasmas by using a He--Ne laser

Energy Technology Data Exchange (ETDEWEB)

Maejima, Y; Sugimoto, H; Tamaru, T [Electrotechnical Lab., Tanashi, Tokyo (Japan). Tanashi Branch

1975-08-01

The electron density in the plasma of toroidal screw pinch device TPE-1 of the Electrotechnical Laboratory has been measured with a conventional optical interferometer of He-Ne gas laser, 6,328 A in wavelength. The minimum phase shift detectable is about 1/300 lambda, equivalent to ..integral..nsub(e)dl=1x10/sup 15/cm/sup -2/. Some problems on this measuring system are presented. As the system uses conventional components, it is easy to construct and handle and is useful for determining plasma parameters in confinement experiments. The confinement time of charged particles is measured. As a result it has been found that the particles escape from the plasma mostly in conformity with the classical diffusion.

Vertical field systems in TPE-1RM15 reversed dield pinch experiment

International Nuclear Information System (INIS)

Shimada, T.; Hirano, Y.; Yagi, Y.; Ogawa, K.; Yamane, M.; Yamaguchi, S.; Oyabu, I.; Murakami, S.

1989-01-01

Design of equilibrium control system in TPE-1RM15 is described in detail, where equilibrium is maintained bij the combinatuion of the error field at shell cuts by the external vertical field with pre-programmed wave form is essential to set up and maintain RPF discharge. Control of the equilibrium position in the vacuum vessel by using DC vertical field inside the shell at the plasma break down phase, which makes it possible to operate DC vertical field in a wide range. Tooidal asymmetry of the feeders of the pulsed vertical field coil located there. This asymmetry is compensated bij the local vertical field of saddle coil wound around the shell cuts. (author). 2 refs.;4 figs

Upgrading elastomer seals for nuclear service

Energy Technology Data Exchange (ETDEWEB)

Wittich, K C; Wensel, R; LaRose, R; Kuran, S

1995-06-01

Pumps, valves and instruments in nuclear plants have historically contained whatever elastomer each equipment supplier traditionally used for corresponding non-nuclear service. The proliferation of elastomer compounds, and their sometimes uncertain reliability, is now being reduced by upgrading and standardizing on a handful of compounds that have each been verified to be high performers for their class of service conditions. The objective is to make cost-effective improvements in the reliability and integrity of equipment in Canadian-designed nuclear plants. The effort focuses on elastomer seals and includes: understanding sealing fundamentals, developing relevant data for superior compounds for each service, and improving quality assurance methods, including handling and inspection guidelines. In practice, discussions with plant personnel and review of plant records are the first step. Two severe-service examples are given where these needs have been met by the following progression of activities: inspecting and laboratory testing of seals removed from service, preliminary and qualification testing of improvements, introduction into service, and monitoring the upgraded seals during phase-in periods. Large gains in reliability and integrity have been demonstrated for simulated normal and accident service conditions of heat, radiation and other deteriorative influences. Significant savings in maintenance costs are also projected. (author). 2 refs., 6 figs.

Upgrading elastomer seals for nuclear service

International Nuclear Information System (INIS)

Wittich, K.C.; Wensel, R.; LaRose, R.; Kuran, S.

1995-06-01

Pumps, valves and instruments in nuclear plants have historically contained whatever elastomer each equipment supplier traditionally used for corresponding non-nuclear service. The proliferation of elastomer compounds, and their sometimes uncertain reliability, is now being reduced by upgrading and standardizing on a handful of compounds that have each been verified to be high performers for their class of service conditions. The objective is to make cost-effective improvements in the reliability and integrity of equipment in Canadian-designed nuclear plants. The effort focuses on elastomer seals and includes: understanding sealing fundamentals, developing relevant data for superior compounds for each service, and improving quality assurance methods, including handling and inspection guidelines. In practice, discussions with plant personnel and review of plant records are the first step. Two severe-service examples are given where these needs have been met by the following progression of activities: inspecting and laboratory testing of seals removed from service, preliminary and qualification testing of improvements, introduction into service, and monitoring the upgraded seals during phase-in periods. Large gains in reliability and integrity have been demonstrated for simulated normal and accident service conditions of heat, radiation and other deteriorative influences. Significant savings in maintenance costs are also projected. (author). 2 refs., 6 figs

Upgrading elastomer seals for nuclear service

International Nuclear Information System (INIS)

Wittich, K.C.; Wensel, R.; Larose, R.; Kuran, S.

1998-01-01

Pumps, valves and instruments in nuclear plants have historically contained whatever elastomer each equipment supplier traditionally used for corresponding non-nuclear service. The proliferation of elastomer compounds, and their sometimes uncertain reliability, is now being reduced by upgrading and standardizing on a handful of compounds that have each been verified to be high performers for their class of service conditions. The objective is to make cost-effective improvements in the reliability and integrity of equipment in Canadian-designed nuclear plants. The effort focuses on elastomer seals and includes: understanding sealing fundamentals, developing relevant data for superior compounds for each service, and improving quality assurance methods, including handling and inspection guidelines. In practice, discussion with plant personnel and review of plant records are the first step. Two severe-service examples are given where these needs have been met by the following progression of activities: inspecting and laboratory testing of seals removed from service, preliminary and qualification testing of improvements, introduction into service, and monitoring the upgraded seals during phase-in periods. Large gains in reliability and integrity have been demonstrated for simulated normal and accident service conditions of heat, radiation and other deteriorative influences. Significant savings in maintenance costs are also projected. (author)

The tensile strength test of thermoplastic materials based on poly(butylene terephtalate

Directory of Open Access Journals (Sweden)

Rzepecka Anna

2017-01-01

Full Text Available Thermoplastic composites go toward making an increasingly greater percentage of all manufacturing polymer composites. They have a lot of beneficial properties and their manufacturing using injecting and extrusion methods is a very easy and cheap process. Their properties significantly overtake the properties of traditional materials and it is the reason for their use. Scientists are continuously carrying out research to find new applications of composites materials in new industries, not only in the automotive or aircraft industry. When thermoplastic composites are manufactured a very important factor is the appropriate accommodation of tensile strength to their predestination. Scientists need to know the behaviour of these materials during the impact of different forces, and the factors of working in normal conditions too. The main aim of this article was macroscopic and microscopic analysis of the structure of thermoplastic composites after static tensile strength test. Materials which were analysed were thermoplastic materials which have poly(butylene terephthalate – PBT matrix reinforced with different content glass fibres – from 10% for 30%. In addition, research showed the necessary force to receive fracture and set their distinguishing characteristic down.

Attribute Based Selection of Thermoplastic Resin for Vacuum Infusion Process: A Decision Making Methodology

DEFF Research Database (Denmark)

Raghavalu Thirumalai, Durai Prabhakaran; Lystrup, Aage; Løgstrup Andersen, Tom

2012-01-01

The composite industry looks toward a new material system (resins) based on thermoplastic polymers for the vacuum infusion process, similar to the infusion process using thermosetting polymers. A large number of thermoplastics are available in the market with a variety of properties suitable...... be beneficial. In this paper, the authors introduce a new decision making tool for resin selection based on significant attributes. This article provides a broad overview of suitable thermoplastic material systems for vacuum infusion process available in today’s market. An illustrative example—resin selection...... for vacuum infused of a wind turbine blade—is shown to demonstrate the intricacies involved in the proposed methodology for resin selection....

Inkjet 3D printing of UV and thermal cure silicone elastomers for dielectric elastomer actuators

Science.gov (United States)

McCoul, David; Rosset, Samuel; Schlatter, Samuel; Shea, Herbert

2017-12-01

Dielectric elastomer actuators (DEAs) are an attractive form of electromechanical transducer, possessing high energy densities, an efficient design, mechanical compliance, high speed, and noiseless operation. They have been incorporated into a wide variety of devices, such as microfluidic systems, cell bioreactors, tunable optics, haptic displays, and actuators for soft robotics. Fabrication of DEA devices is complex, and the majority are inefficiently made by hand. 3D printing offers an automated and flexible manufacturing alternative that can fabricate complex, multi-material, integrated devices consistently and in high resolution. We present a novel additive manufacturing approach to DEA devices in which five commercially available, thermal and UV-cure DEA silicone rubber materials have been 3D printed with a drop-on-demand, piezoelectric inkjet system. Using this process, 3D structures and high-quality silicone dielectric elastomer membranes as thin as 2 μm have been printed that exhibit mechanical and actuation performance at least as good as conventionally blade-cast membranes. Printed silicone membranes exhibited maximum tensile strains of up to 727%, and DEAs with printed silicone dielectrics were actuated up to 6.1% area strain at a breakdown strength of 84 V μm-1 and also up to 130 V μm-1 at 2.4% strain. This approach holds great potential to manufacture reliable, high-performance DEA devices with high throughput.

High performance thermoplastics: A review of neat resin and composite properties

Science.gov (United States)

Johnston, Norman J.; Hergenrother, Paul M.

1987-01-01

A review was made of the principal thermoplastics used to fabricate high performance composites. Neat resin tensile and fracture toughness properties, glass transition temperatures (Tg), crystalline melt temperatures (Tm) and approximate processing conditions are presented. Mechanical properties of carbon fiber composites made from many of these thermoplastics are given, including flexural, longitudinal tensile, transverse tensile and in-plane shear properties as well as short beam shear and compressive strengths and interlaminar fracture toughness. Attractive features and problems involved in the use of thermo-plastics as matrices for high performance composites are discussed.

Optimization of large-scale fabrication of dielectric elastomer transducers

DEFF Research Database (Denmark)

Hassouneh, Suzan Sager

Dielectric elastomers (DEs) have gained substantial ground in many different applications, such as wave energy harvesting, valves and loudspeakers. For DE technology to be commercially viable, it is necessary that any large-scale production operation is nondestructive, efficient and cheap. Danfoss......-strength laminates to perform as monolithic elements. For the front-to-back and front-to-front configurations, conductive elastomers were utilised. One approach involved adding the cheap and conductive filler, exfoliated graphite (EG) to a PDMS matrix to increase dielectric permittivity. The results showed that even...... as conductive adhesives were rejected. Dielectric properties below the percolation threshold were subsequently investigated, in order to conclude the study. In order to avoid destroying the network structure, carbon nanotubes (CNTs) were used as fillers during the preparation of the conductive elastomers...

75 FR 39664 - Grant of Authority For Subzone Status Materials Science Technology, Inc. (Specialty Elastomers...

Science.gov (United States)

2010-07-12

... Status Materials Science Technology, Inc. (Specialty Elastomers and Fire Retardant Chemicals) Conroe... specialty elastomer manufacturing and distribution facility of Materials Science Technology, Inc., located... and distribution of specialty elastomers and fire retardant chemicals at the facility of Materials...

The effects of additives on the actuating performances of a dielectric elastomer actuator

International Nuclear Information System (INIS)

Nguyen, Huu Chuc; Doan, Vu Thuy; Park, JongKil; Koo, Ja Choon; Choi, Hyouk Ryeol; Lee, Youngkwan; Nam, Jae-do

2009-01-01

This paper presents a comprehensive study of the effects of additives on the performance of a dielectric elastomer actuator. Previously, a new dielectric elastomer material, called 'synthetic elastomer', was presented for the means of actuation, which permits changes in the mechanical as well as the electrical properties in order to meet the requirements of certain applications. This work studies how the electromechanical properties of the synthetic elastomer can be adjusted by combining two additives, namely dioctyl phthalate (DOP) and titanium dioxide (TiO 2 ). Experiments are carried out and the effects of each additive are compared to one another based on the actuation performances

Development and evaluation of thermoplastic street maintenance material

Science.gov (United States)

Siemens, W. D.

1973-01-01

An all-weather permanent street patching material was investigated for flexible and rigid pavements. The economic, operational, and material requirements are discussed along with the results of field tests with various mixtures of EVA resins and asphalt. Cost analyses for thermoplastic patching methods are included.

Enhancement of dielectric permittivity by incorporating PDMS-PEG multiblock copolymers in silicone elastomers

DEFF Research Database (Denmark)

A Razak, Aliff Hisyam; Szabo, Peter; Skov, Anne Ladegaard

2015-01-01

A silicone elastomer from PDMS-PEG multiblock copolymer has been prepared by use of silylation reactions for both copolymer preparation and crosslinking. The dielectric and mechanical properties of the silicone elastomers were carefully investigated, as well as the morphology of the elastomers wa...... to a significantly increased dielectric permittivity. The conductivity also remained low due to the resulting discontinuity in PEG within the silicone matrix....

Silicone elastomers with high dielectric permittivity and high dielectric breakdown strength based on dipolar copolymers

DEFF Research Database (Denmark)

Madsen, Frederikke Bahrt; Yu, Liyun; Daugaard, Anders Egede

2014-01-01

Dielectric elastomers (DES) are a promising new transducer technology, but high driving voltages limit their current commercial potential. One method used to lower driving voltage is to increase dielectric permittivity of the elastomer. A novel silicone elastomer system with high dielectric...

Method for bonding a thermoplastic polymer to a thermosetting polymer component

NARCIS (Netherlands)

Van Tooren, M.J.L.

2012-01-01

The invention relates to a method for bonding a thermoplastic polymer to a thermosetting polymer component, the thermoplastic polymer having a melting temperature that exceeds the curing temperature of the thermosetting polymer. The method comprises the steps of providing a cured thermosetting

In vitro cytotoxicity of maxillofacial silicone elastomers: effect of accelerated aging.

Science.gov (United States)

Bal, Bilge Turhan; Yilmaz, Handan; Aydin, Cemal; Karakoca, Seçil; Yilmaz, Sükran

2009-04-01

The purpose of this in vitro study was to evaluate the cytotoxicity of three maxillofacial silicone elastomers at 24, 48, and 72 h on L-929 cells and to determine the effect of accelerated aging on the cytotoxicity of these silicone elastomers. Disc-shaped test samples of maxillofacial silicone elastomers (Cosmesil, Episil, Multisil) were fabricated according to manufacturers' instructions under aseptic conditions. Samples were then divided into three groups: (1) not aged; (2) aged for 150 h with an accelerated weathering tester; and (3) aged for 300 h. Then the samples were placed in Dulbecco's Modified Eagle Medium/Ham's F12 (DMEM/F12) for 24, 48, and 72 h. After the incubation periods, cytotoxicity of the extracts to cultured fibroblasts (L-929) was measured by MTT assay. The degree of cytotoxicity of each sample was determined according to the reference value represented by the cells with a control (culture without sample). Statistical significance was determined by repeated measurement ANOVA (p test (p test materials in each group demonstrated high survival rates in MTT assay (Episil; 93.84%, Multisil; 88.30%, Cosmesil; 87.50%, respectively); however, in all groups, Episil material demonstrated significantly higher cell survival rate after each of the experimental incubation periods (p Accelerated aging for 150 and 300 h had no significant effect on the biocompatibility of maxillofacial silicone elastomers tested (p > 0.05).

Hydrogen release from irradiated elastomers measured by Nuclear Reaction Analysis

Energy Technology Data Exchange (ETDEWEB)

Jagielski, J., E-mail: jacek.jagielski@itme.edu.pl [Institute for Electronic Materials Technology, Wolczynska 133, 01-926 Warszawa (Poland); National Centre for Nuclear Research, A. Soltana 7, 05-400 Swierk/Otwock (Poland); Ostaszewska, U. [Institute for Engineering of Polymer Materials & Dyes, Division of Elastomers & Rubber Technology, Harcerska 30, 05-820 Piastow (Poland); Bielinski, D.M. [Technical University of Lodz, Institute of Polymer & Dye Technology, Stefanowskiego 12/16, 90-924 Lodz (Poland); Grambole, D. [Institute of Ion Beam Physics and Materials Research, Helmholtz Zentrum Dresden Rossendorf, PO Box 51 01 19, D-01314 Dresden (Germany); Romaniec, M.; Jozwik, I.; Kozinski, R. [Institute for Electronic Materials Technology, Wolczynska 133, 01-926 Warszawa (Poland); Kosinska, A. [National Centre for Nuclear Research, A. Soltana 7, 05-400 Swierk/Otwock (Poland)

2016-03-15

Ion irradiation appears as an interesting method of modification of elastomers, especially friction and wear properties. Main structural effect caused by heavy ions is a massive loss of hydrogen from the surface layer leading to its smoothening and shrinking. The paper presents the results of hydrogen release from various elastomers upon irradiation with H{sup +}, He{sup +} and Ar{sup +} studied by using Nuclear Reaction Analysis (NRA) method. The analysis of the experimental data indicates that the hydrogen release is controlled by inelastic collisions between ions and target electrons. The last part of the study was focused on preliminary analysis of mechanical properties of irradiated rubbers.

Development of procedures for calculating stiffness and damping properties of elastomers in engineering applications. Part 4: Testing of elastomers under a rotating load. [resonance testing

Science.gov (United States)

Darlow, M. S.; Smalley, A. J.

1977-01-01

A test rig designed to measure stiffness and damping of elastomer cartridges under a rotating load excitation is described. The test rig employs rotating unbalance in a rotor which runs to 60,000 RPM as the excitation mechanism. A variable resonant mass is supported on elastomer elements and the dynamic characteristics are determined from measurements of input and output acceleration. Five different cartridges are considered: three of these are buttons cartridges having buttons located in pairs, with 120 between each pair. Two of the cartridges consist of 360 elastomer rings with rectangular cross-sections. Dynamic stiffness and damping are measured for each cartridge and compared with predictions at different frequencies and different strains.

Toughened nanocomposites of polyamide-6 and polyepichlorohydrin elastomer: mechanical and morphological properties

International Nuclear Information System (INIS)

Pinotti, Caio A.; Goncalves, Maria C.; Felisberti, Maria I.

2009-01-01

Blends of polyamide 6, P A6, and polyepichlorohydrin elastomer, PE Pi, nano composites of P A6 and OMMT and toughened nano composites, P A6/PE Pi/OMMT were prepared by twin-screw extrusion. Nanocomposites of P A6 and organophilic clay presented morphology of exfoliated clay with the presence of some tactoids, which were investigated by XRD and TEM. The blends P A6/PE Pi are immiscible with morphology of elastomer disperse phase. The size of the elastomer phase in the PA6 matrix and a better distribution of these phase were achieved with the incorporation of the clay in the ternary nanocomposites. Toughened nano composites presented increases in Young's modulus, Izod impact strength and yield stress, comparing with the blends of P A6 and polyepichlorohydrin elastomer. (author)

Reduction of the Adhesive Friction of Elastomers through Laser Texturing of Injection Molds

Directory of Open Access Journals (Sweden)

Joel Voyer

2017-11-01

Full Text Available It is well known that elastomers usually possess poor dry sliding friction properties due to their highly adhesive character. In order to overcome this problematic behavior in industrial applications, interfacial materials such as oils, greases, coatings, or lacks are normally used in order to separate or to functionalize the contact surfaces of elastomers. Alternatively, the high adhesion tendency of elastomers may be explicitly reduced by modifying the elastomer composition itself or by enabling a reduction of its effective contact area through, for example, surface laser texturing. This second approach, i.e., the reduction of the adhesive character of elastomers through laser structuring, will be the main topic of the present study. For this purpose, different micro-sized grooved structures were produced on flat injection molds using an ultra-short pulsed laser. The micro-structured molds were then used to produce injection molded micro-ridged Liquid Silicone Rubber (LSR sample pads. The investigations consisted firstly of determining the degree of replication of the mold micro-structures onto the surface of the LSR pads and secondly, to ascertain the degree of reduction of the friction force (or coefficient of friction of these micro-ridged LSR pads in comparison to the benchmark (unstructured LSR pads when tested under dry conditions against Aluminum alloy (Al-6082 or PA6.6-GF30 plates. For this second part of the investigation, the normal force (or contact pressure dependency of the coefficient of friction was determined through stepwise load increasing friction tests. The results of these investigations have shown that the production of micro-ridged surfaces on LSR pads through laser structuring of the injection molds could be successfully achieved and that it enables a significant reduction of the friction force for low normal forces (or contact pressures, where the component of adhesion friction is playing an important and determining

Examination of injection moulded thermoplastic maize starch

Directory of Open Access Journals (Sweden)

2007-12-01

Full Text Available This paper focuses on the effect of the different injection moulding parameters and storing methods on injection moulded thermoplastic maize starch (TPS. The glycerol and water plasticized starch was processed in a twin screw extruder and then with an injection moulding machine to produce TPS dumbbell specimens. Different injection moulding set-ups and storing conditions were used to analyse the effects on the properties of thermoplastic starch. Investigated parameters were injection moulding pressure, holding pressure, and for the storage: storage at 50% relative humidity, and under ambient conditions. After processing the mechanical and shrinkage properties of the manufactured TPS were determined as a function of the ageing time. While conditioning, the characteristics of the TPS changed from a soft material to a rigid material. Although this main behaviour remained, the different injection moulding parameters changed the characteristics of TPS. Scanning electron microscope observations revealed the changes in the material on ageing.

Polyurethane elastomers in armour applications

NARCIS (Netherlands)

Carton, E.P.; Broos, J.P.F.

2012-01-01

The use of elastomers in ballistic protection products (armour) is limited to low threat levels and transparent armour solution components. Often armor is considered a parasitic mass that increases with increasing threat levels. Therefore, low weight solutions are welcomed and bulk polymers,

3D modeling of squeeze flow of unidirectionally thermoplastic composite inserts

Science.gov (United States)

Ghnatios, Chady; Abisset-Chavanne, Emmanuelle; Binetruy, Christophe; Chinesta, Francisco; Advani, Suresh

2016-10-01

Thermoplastic composites are attractive because they can be recycled and exhibit superior mechanical properties. The ability of thermoplastic resin to melt and solidify allows for fast and cost-effective manufacturing processes, which is a crucial property for high volume production. Thermoplastic composite parts are usually obtained by stacking several prepreg plies to create a laminate with a particular orientation sequence to meet design requirements. During the consolidation and forming process, the thermoplastic laminate is subjected to complex deformation which can include intraply and/or interply shear, ply reorientation and squeeze flow. In the case of unidirectional prepregs, the ply constitutive equation, when elastic effects are neglected, can be modeled as a transversally isotropic fluid, that must satisfy the fiber inextensibility as well as the fluid incompressibility. The high-fidelity solution of the squeeze flow in laminates composed of unidirectional prepregs was addressed in our former works by making use of an in-plane-out-of-plane separated representation allowing a very detailed resolution of the involved fields throughout the laminate thickness. In the present work prepregs plies are supposed of limited dimensions compared to the in-plane dimension of the part and will be named inserts. Again within the Proper Generalized Decomposition framework high-resolution simulation of the squeeze flow occurring during consolidation is addressed within a fully 3D in-plane-out-of-plane separated representation.

Training and qualification of the auxiliaries of operation using the methodology On the Job Training (OJT) and Task Performance Evaluation (TPE)

International Nuclear Information System (INIS)

Martinez Casado, J.

2015-01-01

On the Job Training (OJT) and Task Performance Evaluation (TPE). This plan has been developed and put in practice entirely, by a group of experienced auxiliary operation that have distinguished themselves by their professionalism, knowledge of the work, technical expertise and commitment to nuclear safety. (Author)

Bi-axially crumpled silver thin-film electrodes for dielectric elastomer actuators

International Nuclear Information System (INIS)

Low, Sze-Hsien; Lau, Gih-Keong

2014-01-01

Metal thin films, which have high conductivity, are much stiffer and may fracture at a much lower strain than dielectric elastomers. In order to fabricate compliant electrodes for use in dielectric elastomer actuators (DEAs), metal thin films have been formed into either zigzag patterns or corrugations, which favour bending and only allow uniaxial DEA deformations. However, biaxially compliant electrodes are desired in order to maximize generated forces of DEA. In this paper, we present crumpled metal thin-film electrodes that are biaxially compliant and have full area coverage over the dielectric elastomer. These crumpled metal thin-film electrodes are more stretchable than flat metal thin films; they remain conductive beyond 110% radial strain. Also, crumpling reduced the stiffening effect of metal thin films on the soft elastomer. As such, DEAs using crumpled metal thin-film electrodes managed to attain relatively high actuated area strains of up to 128% at 1.8 kV (102 Vμm −1 ). (paper)

Data acquisition system in TPE-1RM15

International Nuclear Information System (INIS)

Yagi, Yasuyuki; Yahagi, Eiichi; Hirano, Yoichi; Shimada, Toshio; Hirota, Isao; Maejima, Yoshiki

1991-01-01

The data acquisition system for TPE-1RM15 reversed field pinch machine had been developed and has recently been completed. Thd data to be acquired consist of many channels of time series data which come from plasma diagnostics. The newly developed data acquisition system uses CAMAC (Computer Automated Measurement And Control) system as a front end data acquisition system and micro-VAX II for control, file management and analyses. Special computer programs, DAQR/D, have been developed for data acquisition routine. Experimental setting and process controlling items are managed by a parameter database in a shared common region and every task can easily refer to it. The acquired data are stored into a mass storage system (total of 1.3GBytes plus a magnetic tape system) including an optical disk system, which can save storage space and allow quick reference. At present, the CAMAC system has 88 (1MHz sampling) and 64(5kHz sampling) channels corresponding to 1.6 MBytes per shot. The data acquisition system can finish one routine within 5 minutes with 1.6MBytes data depending on the amount of graphic outputs. Hardwares and softwares of the system are specified so that the system can be easily expanded. The computer is connected to the AIST Ethernet and the system can be remotely accessed and the acquired data can be transferred to the mainframes on the network. Details about specifications and performance of the system are given in this report. (author)

Complaint liquid metal electrodes for dielectric elastomer actuators

Science.gov (United States)

Finkenauer, Lauren R.; Majidi, Carmel

2014-03-01

This work presents a liquid-phase metal electrode to be used with poly(dimethylsiloxane) (PDMS) for a dielectric elastomer actuator (DEA). DEAs are favorable for soft-matter applications where high efficiency and response times are desirable. A consistent challenge faced during the fabrication of these devices is the selection and deposition of electrode material. While numerous designs have been demonstrated with a variety of conductive elastomers and greases, these materials have significant and often intrinsic shortcomings, e.g. low conductivity, hysteresis, incapability of large deformations, and complex fabrication requirements. The liquid metal alloy eutectic Gallium-Indium (EGaIn) is a promising alternative to existing compliant electrodes, having both high conductivity and complete soft-matter functionality. The liquid electrode shares almost the same electrical conductivity as conventional metal wiring and provides no mechanical resistance to bending or stretching of the DEA. This research establishes a straightforward and effective method for quickly depositing EGaIn electrodes, which can be adapted for batch fabrication, and demonstrates the successful actuation of sample curved cantilever elastomer actuators using these electrodes. As with the vast majority of electrostatically actuated elastomer devices, the voltage requirements for these curved DEAs are still quite significant, though modifications to the fabrication process show some improved electrical properties. The ease and speed with which this method can be implemented suggests that the development of a more electronically efficient device is realistic and worthwhile.

Electrical behaviour of synthetic elastomers under gamma irradiation

International Nuclear Information System (INIS)

Zaharescu, Traian; Ciuprina, Florin

2006-01-01

The exposure of ethylene-propylene elastomers to the action of gamma radiation causes the modification of chemical state of polymer matrix by the formation of oxygenated products. The accumulation of dipoles modifies the electrical behaviour of materials. The value of resistance increases more than three times at increasing the dose up to 200 kGy. The absorption/resorption current measurements demonstrate the bad consequence of the inversion of polarity for applied voltages. Differences between the two sorts of synthetic elastomers (ethylene-propylene copolymer and ethylene-propylene terpolymer) were pointed out. (author)

Glycerol as high-permittivity liquid filler in dielectric silicone elastomers

DEFF Research Database (Denmark)

Mazurek, Piotr Stanislaw; Yu, Liyun; Gerhard, R.

2016-01-01

A recently reported novel class of elastomers was tested with respect to its dielectric properties. The new elastomer materialis based on a commercially available poly(dimethylsiloxane) composition, which has been modified by embedding glycerol droplets intoits matrix. The approach has two major ......, and the applicability ofthe models is discussed. VC 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44153....

Development of energy-harvesting system using deformation of magnetic elastomer

Science.gov (United States)

Shinoda, Hayato; Tsumori, Fujio

2018-06-01

In this paper, we propose a power generation method using the deformation of a magnetic elastomer for vibration energy harvesting. The magnetic flux lines in the structure of the magnetic elastomer could be markedly changed if the properly designed structure was expanded and contracted in a static magnetic field. We set a coil on the magnetic elastomer to generate electricity by capturing this change in magnetic flux flow. We fabricated a centimeter-scale device and demonstrated that it generated 10.5 mV of maximum voltage by 10 Hz vibration. We also simulated the change in the magnetic flux flow using finite element analysis, and compared the result with the experimental data. Furthermore, we evaluated the power generation of a miniaturized device.

A survey on dielectric elastomer actuators for soft robots.

Science.gov (United States)

Gu, Guo-Ying; Zhu, Jian; Zhu, Li-Min; Zhu, Xiangyang

2017-01-23

Conventional industrial robots with the rigid actuation technology have made great progress for humans in the fields of automation assembly and manufacturing. With an increasing number of robots needing to interact with humans and unstructured environments, there is a need for soft robots capable of sustaining large deformation while inducing little pressure or damage when maneuvering through confined spaces. The emergence of soft robotics offers the prospect of applying soft actuators as artificial muscles in robots, replacing traditional rigid actuators. Dielectric elastomer actuators (DEAs) are recognized as one of the most promising soft actuation technologies due to the facts that: i) dielectric elastomers are kind of soft, motion-generating materials that resemble natural muscle of humans in terms of force, strain (displacement per unit length or area) and actuation pressure/density; ii) dielectric elastomers can produce large voltage-induced deformation. In this survey, we first introduce the so-called DEAs emphasizing the key points of working principle, key components and electromechanical modeling approaches. Then, different DEA-driven soft robots, including wearable/humanoid robots, walking/serpentine robots, flying robots and swimming robots, are reviewed. Lastly, we summarize the challenges and opportunities for the further studies in terms of mechanism design, dynamics modeling and autonomous control.

Development of procedures for calculating stiffness and damping of elastomers in engineering applications, part 6

Science.gov (United States)

Rieger, A.; Burgess, G.; Zorzi, E.

1980-01-01

An elastomer damper was designed, tested, and compared with the performance of a hydraulic damper for a power transmission shaft. The six button Viton-70 damper was designed so that the elastomer damper or the hydraulic damper could be activated without upsetting the imbalance condition of the assembly. This permitted a direct comparison of damper effectiveness. The elastomer damper consistently performed better than the hydraulic mount and permitted stable operation of the power transmission shaft to speeds higher than obtained with the squeeze film damper. Tests were performed on shear specimens of Viton-79, Buna-N, EPDM, and Neoprene to determine performance limitations imposed by strain, temperature, and frequency. Frequencies of between 110 Hz and 1100 Hz were surveyed with imposed strains between 0.0005 and 0.08 at temperatures of 32 C, 66 C, and 80 C. A set of design curves was generated in a unified format for each of the elastomer materials.

The development of an alternative thermoplastic powder prepregging technique

Science.gov (United States)

Ogden, A. L.; Hyer, M. W.; Wilkes, G. L.; Loos, A. C.

1992-01-01

An alternative powder prepregging technique is discussed that is based on the deposition of powder onto carbon fibers that have been moistened using an ultrasonic humidifier. The dry fiber tow is initially spread to allow a greater amount of the fiber surface to be exposed to the powder, thus ensuring a significant amount of intimate contact between the fiber and the matrix. Moisture in the form of ultrafine water droplets is then deposited onto the spread fiber tow. The moisture promotes adhesion to the fiber until the powder can be tacked to the fibers by melting. Powdered resin is then sieved onto the fibers and then tacked onto the fibers by quick heating in a convective oven. This study focuses on the production of prepregs and laminates made with LaRC-TPI (thermoplastic polyimide) using this process. Although the process appears to be successful, early evaluation was hampered by poor interfacial adhesion. The adhesion problem, however, seems to be the result of a material system incompatibility, rather than being influenced by the process.

Parameters design of the dielectric elastomer spring-roll bending actuator (Conference Presentation)

Science.gov (United States)

Li, Jinrong; Liu, Liwu; Liu, Yanju; Leng, Jinsong

2017-04-01

Dielectric elastomers are novel soft smart material that could deform sustainably when subjected to external electric field. That makes dielectric elastomers promising materials for actuators. In this paper, a spring-roll actuator that would bend when a high voltage is applied was fabricated based on dielectric elastomer. Using such actuators as active parts, the flexible grippers and inchworm-inspired crawling robots were manufactured, which demonstrated some examples of applications in soft robotics. To guide the parameters design of dielectric elastomer based spring-roll bending actuators, the theoretical model of such actuators was established based on thermodynamic theories. The initial deformation and electrical induced bending angle of actuators were formulated. The failure of actuators was also analyzed considering some typical failure modes like electromechanical instability, electrical breakdown, loss of tension and maximum tolerant stretch. Thus the allowable region of actuators was determined. Then the bending angle-voltage relations and failure voltages of actuators with different parameters, including stretches of the dielectric elastomer film, number of active layers, and dimensions of spring, were investigated. The influences of each parameter on the actuator performances were discussed, providing meaningful guidance to the optical design of the spring-roll bending actuators.

Nanomechanical probing of thin-film dielectric elastomer transducers

Science.gov (United States)

Osmani, Bekim; Seifi, Saman; Park, Harold S.; Leung, Vanessa; Töpper, Tino; Müller, Bert

2017-08-01

Dielectric elastomer transducers (DETs) have attracted interest as generators, actuators, sensors, and even as self-sensing actuators for applications in medicine, soft robotics, and microfluidics. Their performance crucially depends on the elastic properties of the electrode-elastomer sandwich structure. The compressive displacement of a single-layer DET can be easily measured using atomic force microscopy (AFM) in the contact mode. While polymers used as dielectric elastomers are known to exhibit significant mechanical stiffening for large strains, their mechanical properties when subjected to voltages are not well understood. To examine this effect, we measured the depths of 400 nanoindentations as a function of the applied electric field using a spherical AFM probe with a radius of (522 ± 4) nm. Employing a field as low as 20 V/μm, the indentation depths increased by 42% at a load of 100 nN with respect to the field-free condition, implying an electromechanically driven elastic softening of the DET. This at-a-glance surprising experimental result agrees with related nonlinear, dynamic finite element model simulations. Furthermore, the pull-off forces rose from (23.0 ± 0.4) to (49.0 ± 0.7) nN implying a nanoindentation imprint after unloading. This embossing effect is explained by the remaining charges at the indentation site. The root-mean-square roughness of the Au electrode raised by 11% upon increasing the field from zero to 12 V/μm, demonstrating that the electrode's morphology change is an undervalued factor in the fabrication of DET structures.

A micro-macro constitutive model for finite-deformation viscoelasticity of elastomers with nonlinear viscosity

Science.gov (United States)

Zhou, Jianyou; Jiang, Liying; Khayat, Roger E.

2018-01-01

Elastomers are known to exhibit viscoelastic behavior under deformation, which is linked to the diffusion processes of the highly mobile and flexible polymer chains. Inspired by the theories of polymer dynamics, a micro-macro constitutive model is developed to study the viscoelastic behaviors and the relaxation process of elastomeric materials under large deformation, in which the material parameters all have a microscopic foundation or a microstructural justification. The proposed model incorporates the nonlinear material viscosity into the continuum finite-deformation viscoelasticity theories which represent the polymer networks of elastomers with an elastic ground network and a few viscous subnetworks. The developed modeling framework is capable of adopting most of strain energy density functions for hyperelastic materials and thermodynamics evolution laws of viscoelastic solids. The modeling capacity of the framework is outlined by comparing the simulation results with the experimental data of three commonly used elastomeric materials, namely, VHB4910, HNBR50 and carbon black (CB) filled elastomers. The comparison shows that the stress responses and some typical behaviors of filled and unfilled elastomers can be quantitatively predicted by the model with suitable strain energy density functions. Particularly, the strain-softening effect of elastomers could be explained by the deformation-dependent (nonlinear) viscosity of the polymer chains. The presented modeling framework is expected to be useful as a modeling platform for further study on the performance of different type of elastomeric materials.

Numerical Modelling of Metal-Elastomer Spring Nonlinear Response for Low-Rate Deformations

Directory of Open Access Journals (Sweden)

Sikora Wojciech

2018-03-01

Full Text Available Advanced knowledge of mechanical characteristics of metal-elastomer springs is useful in their design process and selection. It can also be used in simulating dynamics of machine where such elements are utilized. Therefore this paper presents a procedure for preparing and executing FEM modelling of a single metal-elastomer spring, also called Neidhart’s spring, for low-rate deformations. Elastomer elements were made of SBR rubber of two hardness values: 50°Sh and 70°Sh. For the description of material behaviour the Bergström-Boyce model has been used.

Numerical modeling and experimental validation of thermoplastic composites induction welding

Science.gov (United States)

Palmieri, Barbara; Nele, Luigi; Galise, Francesco

2018-05-01

In this work, a numerical simulation and experimental test of the induction welding of continuous fibre-reinforced thermoplastic composites (CFRTPCs) was provided. The thermoplastic Polyamide 66 (PA66) with carbon fiber fabric was used. Using a dedicated software (JMag Designer), the influence of the fundamental process parameters such as temperature, current and holding time was investigated. In order to validate the results of the simulations, and therefore the numerical model used, experimental tests were carried out, and the temperature values measured during the tests were compared with the aid of an optical pyrometer, with those provided by the numerical simulation. The mechanical properties of the welded joints were evaluated by single lap shear tests.

Methods of Recycling, Properties and Applications of Recycled Thermoplastic Polymers

Directory of Open Access Journals (Sweden)

Mădălina Elena Grigore

2017-11-01

Full Text Available This study aims to provide an updated survey of the main thermoplastic polymers in order to obtain recyclable materials for various industrial and indoor applications. The synthesis approach significantly impacts the properties of such materials and these properties in turn have a significant impact on their applications. Due to the ideal properties of the thermoplastic polymers such as corrosion resistance, low density or user-friendly design, the production of plastics has increased markedly over the last 60 years, becoming more used than aluminum or other metals. Also, recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today.

Magnetic force induced tristability for dielectric elastomer actuators

Science.gov (United States)

Li, Xin-Qiang; Li, Wen-Bo; Zhang, Wen-Ming; Zou, Hong-Xiang; Peng, Zhi-Ke; Meng, Guang

2017-10-01

This paper presents a novel dielectric elastomer actuator (DEA) with three stable states. By introducing magnetic forces and coupling them with two cone dielectric elastomer (DE) films, an inherent tristability for the DEA is obtained with a compact design. It is easy to switch between the three stable states by controlling the voltages applied to the DE films. A theoretical model of the system’s potential energy that contains the free energy of the DEs and the potential energy of the applied magnetic field was developed for the tristable mechanism. The experimental results demonstrate that controllable transitions between the three stable states can be achieved with this design by applying over-critical voltages to the various DE films. The maximum dynamic range of the DEA can exceed 53.8% of the total length of the device and the DE’s creep speed was accelerated under the action of the magnetic field.

Creep and creep-recovery of a thermoplastic resin and composite

Science.gov (United States)

Hiel, Clem

1988-01-01

The database on advanced thermoplastic composites, which is currently available to industry, contains little data on the creep and viscoelastic behavior. This behavior is nevertheless considered important, particularly for extended-service reliability in structural applications. The creep deformation of a specific thermoplastic resin and composite is reviewed. The problem to relate the data obtained on the resin to the data obtained on the composite is discussed.

Mechanical tests for validation of seismic isolation elastomer constitutive models

International Nuclear Information System (INIS)

Kulak, R.F.; Hughes, T.H.

1992-01-01

High damping laminated elastomeric bearings are becoming the preferred device for seismic isolation of large buildings and structures, such as nuclear power plants. The key component of these bearings is a filled natural rubber elastomer. This material exhibits nonlinear behavior within the normal design range. The material damping cannot be classified as either viscous or hysteritic, but it seems to fall somewhere in between. This paper describes a series of tests that can be used to characterize the mechanical response of these elastomers. The tests are designed to determine the behavior of the elastomer in the time scale of the earthquake, which is typically from 30 to 60 seconds. The test results provide data for use in determining the material parameters associated with nonlinear constitutive models. 4 refs

Performance Optimization of a Conical Dielectric Elastomer Actuator

Directory of Open Access Journals (Sweden)

Chongjing Cao

2018-06-01

Full Text Available Dielectric elastomer actuators (DEAs are known as ‘artificial muscles’ due to their large actuation strain, high energy density and self-sensing capability. The conical configuration has been widely adopted in DEA applications such as bio-inspired locomotion and micropumps for its good compactness, ease for fabrication and large actuation stroke. However, the conical protrusion of the DEA membrane is characterized by inhomogeneous stresses, which complicate their design. In this work, we present an analytical model-based optimization for conical DEAs with the three biasing elements: (I linear compression spring; (II biasing mass; and (III antagonistic double-cone DEA. The optimization is to find the maximum stroke and work output of a conical DEA by tuning its geometry (inner disk to outer frame radius ratio a/b and pre-stretch ratio. The results show that (a for all three cases, stroke and work output are maximum for a pre-stretch ratio of 1 × 1 for the Parker silicone elastomer, which suggests the stretch caused by out-of-plane deformation is sufficient for this specific elastomer. (b Stroke maximization is obtained for a lower a/b ratio while a larger a/b ratio is required to maximize work output, but the optimal a/b ratio is less than 0.3 in all three cases. (c The double-cone configuration has the largest stroke while single cone with a biasing mass has the highest work output.

Nanocomposites Based on Thermoplastic Polymers and Functional Nanofiller for Sensor Applications

Directory of Open Access Journals (Sweden)

Serena Coiai

2015-06-01

Full Text Available Thermoplastic polymers like polyolefins, polyesters, polyamide, and styrene polymers are the most representative commodity plastics thanks to their cost-efficient manufacturing processes, excellent thermomechanical properties and their good environmental compatibility, including easy recycling. In the last few decades much effort has been devoted worldwide to extend the applications of such materials by conferring on them new properties through mixing and blending with different additives. In this latter context, nanocomposites have recently offered new exciting possibilities. This review discusses the successful use of nanostructured dispersed substrates in designing new stimuli-responsive nanocomposites; in particular, it provides an updated description of the synthetic routes to prepare nanostructured systems having the typical properties of thermoplastic polymers (continuous matrix, but showing enhanced optical, conductive, and thermal features dependent on the dispersion topology. The controlled nanodispersion of functional labeled clays, noble metal nanoparticles and carbon nanotubes is here evidenced to play a key role in producing hybrid thermoplastic materials that have been used in the design of devices, such as NLO devices, chemiresistors, temperature and deformation sensors.

Nanocomposites Based on Thermoplastic Polymers and Functional Nanofiller for Sensor Applications

Science.gov (United States)

Coiai, Serena; Passaglia, Elisa; Pucci, Andrea; Ruggeri, Giacomo

2015-01-01

Thermoplastic polymers like polyolefins, polyesters, polyamide, and styrene polymers are the most representative commodity plastics thanks to their cost-efficient manufacturing processes, excellent thermomechanical properties and their good environmental compatibility, including easy recycling. In the last few decades much effort has been devoted worldwide to extend the applications of such materials by conferring on them new properties through mixing and blending with different additives. In this latter context, nanocomposites have recently offered new exciting possibilities. This review discusses the successful use of nanostructured dispersed substrates in designing new stimuli-responsive nanocomposites; in particular, it provides an updated description of the synthetic routes to prepare nanostructured systems having the typical properties of thermoplastic polymers (continuous matrix), but showing enhanced optical, conductive, and thermal features dependent on the dispersion topology. The controlled nanodispersion of functional labeled clays, noble metal nanoparticles and carbon nanotubes is here evidenced to play a key role in producing hybrid thermoplastic materials that have been used in the design of devices, such as NLO devices, chemiresistors, temperature and deformation sensors.

Low Cost Processing of Commingled Thermoplastic Composites

Science.gov (United States)

Chiasson, Matthew Lee

A low cost vacuum consolidation process has been investigated for use with commingled thermoplastic matrix composites. In particular, the vacuum consolidation behaviour of commingled polypropylene/glass fibre and commingled nylon/carbon fibre precursors were studied. Laminates were consolidated in a convection oven under vacuum pressure. During processing, the consolidation of the laminate packs was measured by use of non-contact eddy current sensors. The consolidation curves are then used to tune an empirical consolidation model. The overall quality of the resulting laminates is also discussed. Dynamic mechanical analysis, differential scanning calorimetry and mechanical tensile testing were also performed in order to determine the effects of varying processing parameters on the physical and mechanical properties of the laminates. Through this analysis, it was determined that the nylon/carbon fibre blend was not suitable for vacuum consolidation, while the polypropylene/glass fibre blend is a viable option for vacuum consolidation. The ultimate goal of this work is to provide a foundation from which low cost unmanned aerial vehicle (UAV) components can be designed and manufactured from thermoplastic matrix composites using a low cost processing technique as an alternative to traditional thermoset composite materials.

Preparation of micro-pored silicone elastomer through radiation crosslinking

International Nuclear Information System (INIS)

Gao Xiaoling; Gu Mei; Xie Xubing; Huang Wei

2013-01-01

The radiation crosslinking was adopted to prepare the micro-pored silicone elastomer, which was performed by vulcanization and foaming respectively. Radiation crosslinking is a new method to prepare micro-pored material with high performance by use of radiation technology. Silicon dioxide was used as filler, and silicone elastomer was vulcanized by electron beams, then the micro-pored material was made by heating method at a high temperature. The effects of absorbed dose and filler content on the performance and morphology were investigated. The structure and distribution of pores were observed by SEM. The results show that the micro-pored silicon elastomer can be prepared successfully by controlling the absorbed dose and filler content. It has a smooth surface similar to a rubber meanwhile the pores are round and unconnected to each other with the minimum size of 14 μm. And the good mechanical performance can be suitable for further uses. (authors)

Iterative and variational homogenization methods for filled elastomers

Science.gov (United States)

Goudarzi, Taha

Elastomeric composites have increasingly proved invaluable in commercial technological applications due to their unique mechanical properties, especially their ability to undergo large reversible deformation in response to a variety of stimuli (e.g., mechanical forces, electric and magnetic fields, changes in temperature). Modern advances in organic materials science have revealed that elastomeric composites hold also tremendous potential to enable new high-end technologies, especially as the next generation of sensors and actuators featured by their low cost together with their biocompatibility, and processability into arbitrary shapes. This potential calls for an in-depth investigation of the macroscopic mechanical/physical behavior of elastomeric composites directly in terms of their microscopic behavior with the objective of creating the knowledge base needed to guide their bottom-up design. The purpose of this thesis is to generate a mathematical framework to describe, explain, and predict the macroscopic nonlinear elastic behavior of filled elastomers, arguably the most prominent class of elastomeric composites, directly in terms of the behavior of their constituents --- i.e., the elastomeric matrix and the filler particles --- and their microstructure --- i.e., the content, size, shape, and spatial distribution of the filler particles. This will be accomplished via a combination of novel iterative and variational homogenization techniques capable of accounting for interphasial phenomena and finite deformations. Exact and approximate analytical solutions for the fundamental nonlinear elastic response of dilute suspensions of rigid spherical particles (either firmly bonded or bonded through finite size interphases) in Gaussian rubber are first generated. These results are in turn utilized to construct approximate solutions for the nonlinear elastic response of non-Gaussian elastomers filled with a random distribution of rigid particles (again, either firmly

Morphology of Thermoplastic Elastomers:Stereoblock Polypropylene

Energy Technology Data Exchange (ETDEWEB)

Pople, John A

2002-08-06

The morphologies of low-density (0.86 g/cm{sup 3}), elastomeric polypropylene (ePP) derived from bis(2-arylindenyl) hafnium dichloride were investigated using a combination of polarized optical microscopy (OM), differential scanning calorimetry (DSC), wide angle X-ray scattering (WAXS), Fourier transform infrared (FT-IR) spectroscopy, and tapping mode atomic force microscopy (TMAFM). These low-crystallinity polypropylenes, when crystallized isothermally from the melt, exhibit morphologies reminiscent of classical semi-crystalline polymers. The presence of lamellae, cross-hatching, hedrites, and spherulites was revealed by high resolution TM-AFM. These elastomeric polypropylenes can be fractionated into components of different average tacticities and crystallinities, but similar molecular mass. The analysis of the morphologies of all of the fractions revealed both large hierarchical structures and cross-hatching typical of the {alpha}-modification of crystalline isotactic polypropylene for all but the lowest crystalline ether soluble fraction. Evidence for high-melting crystals in all of the fractions are most consistent with a stereoblock microstructure of atactic and isotactic sequences.

Friction of elastomer-on-glass system and direct observation of its frictional interface

International Nuclear Information System (INIS)

Okamoto, Yoshihiro; Nishio, Kazuyuki; Sugiura, Jun-ichi; Hirano, Motohisa; Nitta, Takahiro

2007-01-01

We performed a study on the static friction of PDMS elastomers with well-defined surface topography sliding over glass. An experimental setup for simultaneous measurements of friction force and direct observations of frictional interface has been developed. The static friction force was nearly proportional to normal load. The static friction force was independent of stick time. The simultaneous measurements revealed that the static friction force was proportional to the total area of contact. The coefficient was nearly independent of the surface topography of PDMS elastomers

Effect of the filler on radiolysis of filled elastomers

International Nuclear Information System (INIS)

Komarov, S.A.; Erastov, A.Kh.; Kolesnikov, A.A.; Gostikina, A.V.; Mal'kov, A.M.; Korovkin, V.V.

1987-01-01

The effect of the type and concentration of filler (A-175 Aerosil, PM-75 technical carbon, BS-100 white black, kaolin, titanium oxide) on the radiation yield of elastomers of different chemical nature was studied. The extreme character of the dependence of the radiation yield of paramagnetic centers on the concentration of filler, common to the systems studied, was established; it was due to the features of the colloid chemical structure of the filled elastomers and particularly to processes of cross-linking of the filter

Electric Conductivity and Dielectric-Breakdown Behavior for Polyurethane Magnetic Elastomers.

Science.gov (United States)

Sasaki, Shuhei; Tsujiei, Yuri; Kawai, Mika; Mitsumata, Tetsu

2017-02-23

The electric-voltage dependence of the electric conductivity for cross-linked and un-cross-linked magnetic elastomers was measured at various magnetic fields, and the effect of cross-linking on the electric conductivity and the dielectric-breakdown behavior was investigated. The electric conductivity for un-cross-linked elastomers at low voltages was independent of magnetic fields and the volume fraction of magnetic particles, indicating the electric conduction in the polyurethane matrix. At high voltages, the electric conductivity increased with the magnetic field, showing the electric conduction via chains of magnetic particles. On the other hand, the electric conductivity at low voltages for cross-linked elastomers with volume fractions below 0.06 was independent of the magnetic field, suggesting the electric conduction in the polyurethane matrix. At volume fractions above 0.14, the electric conductivity increased with the magnetic field, suggesting the electric conduction via chains of magnetic particles. At high voltages, the electric conductivity for cross-linked elastomers with a volume fraction of 0.02 was independent of the magnetic field, indicating the electric conduction through the polyurethane matrix. At volume fractions above 0.06, the electric conductivity suddenly increased at a critical voltage, exhibiting the dielectric breakdown at the bound layer of magnetic particles and/or the discontinuous part between chains.

Properties and performance of flax yarn/thermoplastic polyester composites

DEFF Research Database (Denmark)

Madsen, Bo; Mehmood, Shahid

2012-01-01

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

Soft Dielectric Elastomer Oscillators Driving Bioinspired Robots.

Science.gov (United States)

Henke, E-F Markus; Schlatter, Samuel; Anderson, Iain A

2017-12-01

Entirely soft robots with animal-like behavior and integrated artificial nervous systems will open up totally new perspectives and applications. To produce them, we must integrate control and actuation in the same soft structure. Soft actuators (e.g., pneumatic and hydraulic) exist but electronics are hard and stiff and remotely located. We present novel soft, electronics-free dielectric elastomer oscillators, which are able to drive bioinspired robots. As a demonstrator, we present a robot that mimics the crawling motion of the caterpillar, with an integrated artificial nervous system, soft actuators and without any conventional stiff electronic parts. Supplied with an external DC voltage, the robot autonomously generates all signals that are necessary to drive its dielectric elastomer actuators, and it translates an in-plane electromechanical oscillation into a crawling locomotion movement. Therefore, all functional and supporting parts are made of polymer materials and carbon. Besides the basic design of this first electronic-free, biomimetic robot, we present prospects to control the general behavior of such robots. The absence of conventional stiff electronics and the exclusive use of polymeric materials will provide a large step toward real animal-like robots, compliant human machine interfaces, and a new class of distributed, neuron-like internal control for robotic systems.

On a Minimum Problem in Smectic Elastomers

International Nuclear Information System (INIS)

Buonsanti, Michele; Giovine, Pasquale

2008-01-01

Smectic elastomers are layered materials exhibiting a solid-like elastic response along the layer normal and a rubbery one in the plane. Balance equations for smectic elastomers are derived from the general theory of continua with constrained microstructure. In this work we investigate a very simple minimum problem based on multi-well potentials where the microstructure is taken into account. The set of polymeric strains minimizing the elastic energy contains a one-parameter family of simple strain associated with a micro-variation of the degree of freedom. We develop the energy functional through two terms, the first one nematic and the second one considering the tilting phenomenon; after, by developing in the rubber elasticity framework, we minimize over the tilt rotation angle and extract the engineering stress

Chemical modification and blending of polymers in an extruder reactor

International Nuclear Information System (INIS)

Prut, Eduard V; Zelenetskii, Alexandr N

2001-01-01

Chemical modification and blending of polymers in an extruder reactor are discussed. Relationships between the parameters affecting the reaction kinetics, viz., mixing time, duration of a chemical reaction and the residence time of the system in the extruder reactor, and the structure of the materials produced are analysed. The mechanisms of (i) grafting of low-molecular-mass compounds onto polymers; (ii) reactions between terminal groups of different polymers and (iii) transesterification and interchange reactions are considered. The factors affecting the mechanism of dynamic vulcanisation and the properties of thermoplastic elastomers are identified. Solid-phase reactions of polysaccharides in an extruder are discussed. The priority aspects of studies on the chemical modification and blending of polymers are noted. The bibliography includes 90 references.

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-04-15

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

Biobased composites from cross-linked soybean oil and thermoplastic polyurethane

Science.gov (United States)

Soybean oil is an important sustainable material. Crosslinked acrylated epoxidized soybean oil (AESO) is brittle and the incorporation of thermoplastic polyurethane improves its toughness. The hydrophilic functional groups from both oil and polyurethane contribute to the adhesion of the blend compon...

Review of potential processing techniques for the encapsulation of wastes in thermoplastic polymers

International Nuclear Information System (INIS)

Patel, B.R.; Lageraaen, P.R.; Kalb, P.D.

1995-08-01

Thermoplastic encapsulation has been extensively studied at Brookhaven National Laboratory's (BNL) Environmental and Waste Technology Center (EWTC) as a waste encapsulation technology applicable to a wide range of waste types including radioactive, hazardous and mixed wastes. Encapsulation involves processing thermoplastic and waste materials into a waste form product by heating and mixing both materials into a homogeneous molten mixture. Cooling of the melt results in a solid monolithic waste form in which contaminants have been completely surrounded by a polymer matrix. Heating and mixing requirements for successful waste encapsulation can be met using proven technologies available in various types of commercial equipment. Processing techniques for thermoplastic materials, such as low density polyethylene (LDPE), are well established within the plastics industry. The majority of commercial polymer processing is accomplished using extruders, mixers or a combination of these technologies. Extruders and mixers are available in a broad range of designs and are used during the manufacture of consumer and commercial products as well as for compounding applications. Compounding which refers to mixing additives such as stabilizers and/or colorants with polymers, is analogous to thermoplastic encapsulation. Several processing technologies were investigated for their potential application in encapsulating residual sorbent waste in selected thermoplastic polymers, including single-screw extruders, twin-screw extruders, continuous mixers, batch mixers as well as other less conventional devices. Each was evaluated based on operational ease, quality control, waste handling capabilities as well as degree of waste pretreatment required. Based on literature review, this report provides a description of polymer processing technologies, a discussion of the merits and limitations of each and an evaluation of their applicability to the encapsulation of sorbent wastes

Review of potential processing techniques for the encapsulation of wastes in thermoplastic polymers

Energy Technology Data Exchange (ETDEWEB)

Patel, B.R.; Lageraaen, P.R.; Kalb, P.D.

1995-08-01

Thermoplastic encapsulation has been extensively studied at Brookhaven National Laboratory`s (BNL) Environmental and Waste Technology Center (EWTC) as a waste encapsulation technology applicable to a wide range of waste types including radioactive, hazardous and mixed wastes. Encapsulation involves processing thermoplastic and waste materials into a waste form product by heating and mixing both materials into a homogeneous molten mixture. Cooling of the melt results in a solid monolithic waste form in which contaminants have been completely surrounded by a polymer matrix. Heating and mixing requirements for successful waste encapsulation can be met using proven technologies available in various types of commercial equipment. Processing techniques for thermoplastic materials, such as low density polyethylene (LDPE), are well established within the plastics industry. The majority of commercial polymer processing is accomplished using extruders, mixers or a combination of these technologies. Extruders and mixers are available in a broad range of designs and are used during the manufacture of consumer and commercial products as well as for compounding applications. Compounding which refers to mixing additives such as stabilizers and/or colorants with polymers, is analogous to thermoplastic encapsulation. Several processing technologies were investigated for their potential application in encapsulating residual sorbent waste in selected thermoplastic polymers, including single-screw extruders, twin-screw extruders, continuous mixers, batch mixers as well as other less conventional devices. Each was evaluated based on operational ease, quality control, waste handling capabilities as well as degree of waste pretreatment required. Based on literature review, this report provides a description of polymer processing technologies, a discussion of the merits and limitations of each and an evaluation of their applicability to the encapsulation of sorbent wastes.

Preparation and demonstration of poly(dopamine)-triggered attapulgite-anchored polyurethane as a high-performance rod-like elastomer to reinforce soy protein-isolated composites

Science.gov (United States)

Zhao, Shujun; Wen, Yingying; Wang, Zhong; Kang, Haijiao; Li, Jianzhang; Zhang, Shifeng; Ji, Yong

2018-06-01

Nanophase modification is an effective path to improve composite properties, however, it remains a great challenge to increase the mechanical strength of the modified materials without sacrificing elongation and toughness. This study presents a novel and efficient design for interface anchoring of a waterborne polyurethane (WPU) elastomer with attapulgite (ATP) triggered by poly(dopamine) (PDA) formation due to self-polymerization of the dopamine moieties. The WPU-PDA-ATP (WDA) rod-like elastomer served as an active enhancer for a soy protein isolate (SPI)-based composite to facilitate multiple interactions between SPI and the elastomer. As expected, the PDA layer was coated onto ATP, inducing the nanofiller to successfully anchor onto the WPU elastomer, as confirmed by solid-state 13C NMR, XPS, and ATR-FTIR results. Compared with the control SPI-based film, the tensile strength and toughness increased by 145.6% and 118.3% respectively by introducing WDA rod-like elastomer. The water resistance and thermal stability of the prepared SPI composites were also favorable. The proposed approach represents an efficient way to utilize high-performance elastomer in biobased materials to concurrently enhance strength and toughness.

The reactive extrusion of thermoplastic polyurethane

NARCIS (Netherlands)

Verhoeven, Vincent Wilhelmus Andreas

2006-01-01

The objective of this thesis was to increase the understanding of the reactive extrusion of thermoplastic polyurethane. Overall, several issues were identified: • Using a relative simple extrusion model, the reactive extrusion process can be described. This model can be used to further investigate

Studies on Stress-Strain Relationships of Polymeric Materials Used in Space Applications

Science.gov (United States)

Jana, Sadhan C.; Freed, Alan

2002-01-01

A two-year research plan was undertaken in association with Polymers Branch, NASA Glenn Research Center, to carry out experimental and modeling work relating stress and strain behavior of polymeric materials, especially elastomers and vulcanized rubber. An experimental system based on MTS (Mechanical Testing and Simulation) A/T-4 test facility environment has been developed for a broader range of polymeric materials in addition to a design of laser compatible temperature control chamber for online measurements of various strains. Necessary material processing has been accomplished including rubber compounding and thermoplastic elastomer processing via injection molding. A broad suite of testing methodologies has been identified to reveal the complex non-linear mechanical behaviors of rubbery materials when subjected to complex modes of deformation. This suite of tests required the conceptualization, design and development of new specimen geometries, test fixtures, and test systems including development of a new laser based technique to measure large multi-axial deformations. Test data has been generated for some of these new fixtures and has revealed some complex coupling effects generated during multi-axial deformations. In addition, fundamental research has been conducted concerning the foundation principles of rubber thermodynamics and resulting theories of rubber elasticity. Studies have been completed on morphological properties of several thermoplastic elastomers. Finally, a series of steps have been identified to further advance the goals of NASA's ongoing effort.

CT-guided thermoplastic assisted segmentectomy is an optimal breast conserving surgery for breast cancer with nipple discharge

International Nuclear Information System (INIS)

Makita, Masujiro; Gomi, Naoya; Tachikawa, Tomohiro

2004-01-01

Improvement of imaging by injecting contrast agents into the discharging duct and immobilizing the breast mound with a drape-type thermoplastic shell in breast conserving surgery was assessed by evaluating 96 cases of breast cancer patients with nipple discharge treated by partial mastectomy between April 1998 and August 2003. These patients were divided to three groups: Group A was treated by ordinary partial mastectomy or microdochectomy without new methods. Group B underwent contrast imaging without shell immobilization, and Group C received both shell immobilization and contrast imaging. The negative rates of surgical margins in Groups A, B and C were 19.0%, 17.2%, and 37.5%, respectively. The rates of negative ''lateral'' surgical margins in Groups A, B and C were 23.8%, 27.6%, and 50%, respectively. The rate of negative ''lateral'' surgical margins in Group C was significantly higher than that in Group A. Our findings suggest CT-guided thermoplastic assisted segmentectomy, adopting both ductography CT and immobilization by shell, is an optimal breast conserving surgery for breast cancer with nipple discharge. (author)

Electrical breakdown phenomena of dielectric elastomers

DEFF Research Database (Denmark)

Yu, Liyun; Mateiu, Ramona Valentina; Skov, Anne Ladegaard

2017-01-01

years. However, optimization with respect to the dielectric permittivity solely may lead to other problematic phenomena such as premature electrical breakdown. In this work, we focus on the chloro propyl functionalized silicone elastomers prepared in Madsen et al[2] and we investigate the electrical...

Nonlinear electroelastic deformations of dielectric elastomer composites: II - Non-Gaussian elastic dielectrics

Science.gov (United States)

Lefèvre, Victor; Lopez-Pamies, Oscar

2017-02-01

This paper presents an analytical framework to construct approximate homogenization solutions for the macroscopic elastic dielectric response - under finite deformations and finite electric fields - of dielectric elastomer composites with two-phase isotropic particulate microstructures. The central idea consists in employing the homogenization solution derived in Part I of this work for ideal elastic dielectric composites within the context of a nonlinear comparison medium method - this is derived as an extension of the comparison medium method of Lopez-Pamies et al. (2013) in nonlinear elastostatics to the coupled realm of nonlinear electroelastostatics - to generate in turn a corresponding solution for composite materials with non-ideal elastic dielectric constituents. Complementary to this analytical framework, a hybrid finite-element formulation to construct homogenization solutions numerically (in three dimensions) is also presented. The proposed analytical framework is utilized to work out a general approximate homogenization solution for non-Gaussian dielectric elastomers filled with nonlinear elastic dielectric particles that may exhibit polarization saturation. The solution applies to arbitrary (non-percolative) isotropic distributions of filler particles. By construction, it is exact in the limit of small deformations and moderate electric fields. For finite deformations and finite electric fields, its accuracy is demonstrated by means of direct comparisons with finite-element solutions. Aimed at gaining physical insight into the extreme enhancement in electrostriction properties displayed by emerging dielectric elastomer composites, various cases wherein the filler particles are of poly- and mono-disperse sizes and exhibit different types of elastic dielectric behavior are discussed in detail. Contrary to an initial conjecture in the literature, it is found (inter alia) that the isotropic addition of a small volume fraction of stiff (semi

Blended Polyurethane and Tropoelastin as a Novel Class of Biologically Interactive Elastomer

Science.gov (United States)

Wise, Steven G.; Liu, Hongjuan; Yeo, Giselle C.; Michael, Praveesuda L.; Chan, Alex H.P.; Ngo, Alan K.Y.; Bilek, Marcela M.M.; Bao, Shisan

2016-01-01

Polyurethanes are versatile elastomers but suffer from biological limitations such as poor control over cell attachment and the associated disadvantages of increased fibrosis. We address this problem by presenting a novel strategy that retains elasticity while modulating biological performance. We describe a new biomaterial that comprises a blend of synthetic and natural elastomers: the biostable polyurethane Elast-Eon and the recombinant human tropoelastin protein. We demonstrate that the hybrid constructs yield a class of coblended elastomers with unique physical properties. Hybrid constructs displayed higher elasticity and linear stress–strain responses over more than threefold strain. The hybrid materials showed increased overall porosity and swelling in comparison to polyurethane alone, facilitating enhanced cellular interactions. In vitro, human dermal fibroblasts showed enhanced proliferation, while in vivo, following subcutaneous implantation in mice, hybrid scaffolds displayed a reduced fibrotic response and tunable degradation rate. To our knowledge, this is the first example of a blend of synthetic and natural elastomers and is a promising approach for generating tailored bioactive scaffolds for tissue repair. PMID:26857114

Computational modelling of a thermoforming process for thermoplastic starch

Science.gov (United States)

Szegda, D.; Song, J.; Warby, M. K.; Whiteman, J. R.

2007-05-01

Plastic packaging waste currently forms a significant part of municipal solid waste and as such is causing increasing environmental concerns. Such packaging is largely non-biodegradable and is particularly difficult to recycle or to reuse due to its complex composition. Apart from limited recycling of some easily identifiable packaging wastes, such as bottles, most packaging waste ends up in landfill sites. In recent years, in an attempt to address this problem in the case of plastic packaging, the development of packaging materials from renewable plant resources has received increasing attention and a wide range of bioplastic materials based on starch are now available. Environmentally these bioplastic materials also reduce reliance on oil resources and have the advantage that they are biodegradable and can be composted upon disposal to reduce the environmental impact. Many food packaging containers are produced by thermoforming processes in which thin sheets are inflated under pressure into moulds to produce the required thin wall structures. Hitherto these thin sheets have almost exclusively been made of oil-based polymers and it is for these that computational models of thermoforming processes have been developed. Recently, in the context of bioplastics, commercial thermoplastic starch sheet materials have been developed. The behaviour of such materials is influenced both by temperature and, because of the inherent hydrophilic characteristics of the materials, by moisture content. Both of these aspects affect the behaviour of bioplastic sheets during the thermoforming process. This paper describes experimental work and work on the computational modelling of thermoforming processes for thermoplastic starch sheets in an attempt to address the combined effects of temperature and moisture content. After a discussion of the background of packaging and biomaterials, a mathematical model for the deformation of a membrane into a mould is presented, together with its

Hot embossing of microstructures on addition curing polydimethylsiloxane films

DEFF Research Database (Denmark)

Vudayagiri, Sindhu; Yu, Liyun; Hassouneh, Suzan Sager

2013-01-01

The aim of this research work is to establish a hot embossing process for addition curing vinyl-terminated polydimethylsiloxane (PDMS), which are thermosetting elastomers, based on the existing and widely applied technology for thermoplasts. To our knowledge, no known technologies or processes...

Polyether based segmented copolymers with uniform aramid units

NARCIS (Netherlands)

Niesten, M.C.E.J.

2000-01-01

Segmented copolymers with short, glassy or crystalline hard segments and long, amorphous soft segments (multi-block copolymers) are thermoplastic elastomers (TPE’s). The hard segments form physical crosslinks for the amorphous (rubbery) soft segments. As a result, this type of materials combines

From molecular structure to macromolecular organization : keys to design supramolecular biomaterials

NARCIS (Netherlands)

Hutin, M.C.; Burakowska-Meise, E.A.; Appel, W.P.J.; Dankers, P.Y.W.; Meijer, E.W.

2013-01-01

In the past decade, significant progress has been made in the field of biomaterials, for potential applications in tissue engineering or drug delivery. We have recently developed a new class of thermoplastic elastomers, based on ureidopyrimidinone (UPy) quadruple hydrogen bonding motifs. These

Poly(ethylene oxide)/poly(butylene terephthalate) segmented block copolymers: the effect of copolymer composition on physical properties and degradation behavior

NARCIS (Netherlands)

Deschamps, A.A.; Grijpma, Dirk W.; Feijen, Jan

2001-01-01

In this study, the influence of copolymer composition on the physical properties and the degradation behavior of thermoplastic elastomers based on poly(ethylene oxide) (PEO) and poly(butylene terephthalate) (PBT) segments is investigated. These materials are intended to be used in medical

Composite magnetorheological elastomers as dielectrics for plane capacitors: Effects of magnetic field intensity

Directory of Open Access Journals (Sweden)

Maria Balasoiu

Full Text Available The fabrication of composite magnetorheological elastomers (MRECs based on silicone rubber, carbonyl iron microparticles (10% vol. and polyurethane elastomer doped with 0%, 10% and 20% volume concentration TiO2 microparticles is presented. The obtained MRECs have the shape of thin foils and are used as dielectric materials for manufacturing plane capacitors. Using the plane capacitor method and expression of capacitance as a function of magnetic field intensity, combined with linear elasticity theory, the static magnetoelastic model of the composite is obtained and analyzed. Keywords: Magnetorheological elastomer, TiO2 microparticles, Silicone rubber, Carbonyl iron, Plane capacitor, Magnetoelasticity

Thermosetting epoxy resin/thermoplastic system with combined shape memory and self-healing properties

International Nuclear Information System (INIS)

Yao, Yongtao; Wang, Jingjie; Lu, Haibao; Liu, Yanju; Leng, Jinsong; Xu, Ben; Fu, Yongqing

2016-01-01

A novel and facile strategy was proposed to construct a thermosetting/thermoplastic system with both shape memory and self-healing properties based on commercial epoxy resin and poly(ϵ-caprolactone)-PCL. Thermoplastic material is capable of re-structuring and changing the stiffness/modulus when the temperature is above melting temperature. PCL microfiber was used as a plasticizer in epoxy resin–based blends, and served as a ‘hard segment’ to fix a temporary shape of the composites during shape memory cycles. In this study, the electrospun PCL membrane with a porous network structure enabled a homogenous PCL fibrous distribution and optimized interaction between fiber and epoxy resin. The self-healing capability is achieved by phase transition during curing of the composites. The mechanism of the shape memory effect of the thermosetting (rubber)/thermoplastic composite is attributed to the structural design of the thermoplastic network inside the thermosetting resin/rubber matrix. (paper)

Radiation crosslinking of elastomers

International Nuclear Information System (INIS)

Pearson, D.S.

1981-01-01

In the first part of this paper a review is presented of recent results which show that the tensile strength and fatigue life of synthetic elastomers cured by radiation are essentially equivalent to those prepared by other crosslinking techniques. An explanation for the conflict of these new results with the earlier studies on natural rubber is presented. Investigations into the mechanisms and kinetics of crosslinking mentioned above have also shown that the irradiation method should be ideal for preparing well characterized networks. Such materials are useful for testing theoretical relationships between the structure of rubber networks and their stress-strain behavior. The second part of this paper is devoted to this aspect. (author)

Dielectric elastomers with novel highly-conducting electrodes

Science.gov (United States)

Böse, Holger; Uhl, Detlev

2013-04-01

Beside the characteristics of the elastomer material itself, the performance of dielectric elastomers in actuator, sensor as well as generator applications depends also on the properties of the electrode material. Various electrode materials based on metallic particles dispersed in a silicone matrix were manufactured and investigated. Anisotropic particles such as silver-coated copper flakes and silver-coated glass flakes were used for the preparation of the electrodes. The concentration of the metallic particles and the thickness of the electrode layers were varied. Specific conductivities derived from resistance measurements reached about 100 S/cm and surmount those of the reference materials based on graphite and carbon black by up to three orders of magnitude. The high conductivities of the new electrode materials can be maintained even at very large stretch deformations up to 200 %.

A new soft dielectric silicone elastomer matrix with high mechanical integrity and low losses

DEFF Research Database (Denmark)

Madsen, Frederikke Bahrt; Yu, Liyun; Daugaard, Anders Egede

2015-01-01

Though dielectric elastomers (DEs) have many favourable properties, the issue of high driving voltages limits the commercial viability of the technology. Driving voltage can be lowered by decreasing the Young's modulus and increasing the dielectric permittivity of silicone elastomers. A decrease...... in Young's modulus, however, is often accompanied by the loss of mechanical stability and thereby the lifetime of the DE. A new soft elastomer matrix, with no loss of mechanical stability and high dielectric permittivity, was prepared through the use of alkyl chloride-functional siloxane copolymers...

Studies on the structure and properties of thermoplastic starch/luffa fiber composites

International Nuclear Information System (INIS)

Kaewtatip, Kaewta; Thongmee, Jariya

2012-01-01

Highlights: ► Thermoplastic starch/luffa fiber composites were prepared using compression molding. ► The tensile strengths of the composites were higher than for thermoplastic starch. ► Degradation temperatures of the composites were higher than for thermoplastic starch. ► Luffa fiber decreases the water absorption of TPS. -- Abstract: Thermoplastic starch (TPS)/luffa fiber composites were prepared using compression molding. The luffa fiber contents ranged from 0 wt.% to 20 wt.%. The tensile strength of the TPS/luffa fiber composite with 10 wt.% of luffa fiber had a twofold increase compared to TPS. The temperature values of maximum weight loss of the TPS/luffa fiber composites were higher than for TPS. The water absorption of the TPS/luffa fiber composites decreased significantly when the luffa fiber contents increased. The strength of adhesion between the luffa fiber and the TPS matrix was clearly demonstrated by their compatibility presumably due to their similar chemical structures as shown by scanning electron microscope (SEM) micrographs and Fourier transform infrared (FTIR) spectra.

Manufacturing of Liquid-Embedded Elastomers for Stretchable Electronics

Science.gov (United States)

Kramer, Rebecca; Majidi, Carmel; Weaver, James; Wood, Robert

2013-03-01

Future generations of robots, electronics, and assistive medical devices will include systems that are soft, elastically deformable, and may adapt their functionality in unstructured environments. This will require soft active materials for power circuits and sensing of deformation and contact pressure. As the demand for increased elasticity of electrical components heightens, the challenges for functionality revert to basic questions of fabrication, materials, and design. Several designs for soft sensory skins (including strain, pressure and curvature sensors) based on a liquid-embedded-elastomer approach have been developed. This talk will highlight new ``soft MEMS'' manufacturing techniques based on wetting behavior between gallium-indium alloys and elastomers with varying microtextured surface topography. Supported by Harvard MRSEC and the Wyss Institute

Soft Elasticity in Main Chain Liquid Crystal Elastomers

Directory of Open Access Journals (Sweden)

Anselm C. Griffin

2013-06-01

Full Text Available Main chain liquid crystal elastomers exhibit several interesting phenomena, such as three different regimes of elastic response, unconventional stress-strain relationship in one of these regimes, and the shape memory effect. Investigations are beginning to reveal relationships between their macroscopic behavior and the nature of domain structure, microscopic smectic phase structure, relaxation mechanism, and sample history. These aspects of liquid crystal elastomers are briefly reviewed followed by a summary of the results of recent elastic and high-resolution X-ray diffraction studies of the shape memory effect and the dynamics of the formation of the smectic-C chevron-like layer structure. A possible route to realizing auxetic effect at molecular level is also discussed.

Polysiloxane-based luminescent elastomers prepared by thiol-ene "click" chemistry.

Science.gov (United States)

Zuo, Yujing; Lu, Haifeng; Xue, Lei; Wang, Xianming; Wu, Lianfeng; Feng, Shengyu

2014-09-26

Side-chain vinyl poly(dimethylsiloxane) has been modified with mercaptopropionic acid, methyl 3-mercaptopropionate, and mercaptosuccinic acid. Coordinative bonding of Eu(III) to the functionalized polysiloxanes was then carried out and crosslinked silicone elastomers were prepared by thiol-ene curing reactions of these composites. All these europium complexes could be cast to form transparent, uniform, thin elastomers with good flexibility and thermal stability. The networks were characterized by FTIR, NMR, UV/Vis, and luminescence spectroscopy as well as by scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The europium elastomer luminophores exhibited intense red light at 617 nm under UV excitation at room temperature due to the (5)D0 →(7)F2 transition in Eu(III) ions. The newly synthesized luminescent materials offer many advantages, including the desired mechanical flexibility. They cannot be dissolved or fused, and so they have potential for use in optical and electronic applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation on γ-irradiated PP/ethylene acrylic elastomer TPVs by rheological and thermal approaches

Science.gov (United States)

Dutta, Anindya; Ghosh, Anup K.

2018-03-01

Polypropylene (PP) was melt blended with varying concentration of ethylene acrylic elastomer (AEM) in a twin screw extruder and then γ-irradiated at several radiation doses to achieve a series of thermoplastic vulcanizates (TPV). The effect of AEM concentration and γ-irradiation on flow characteristics, crystallization and thermal degradation of blends were explained using melt dynamic rheology, differential scanning calorimetry and thermogravimetric analysis. Gel content values and dynamic rheological data of PP and AEM at different radiation doses confirmed the incessant scissioning of PP chains with radiation doses except for highest radiation dose, where crosslinking of PP chains took place and the incessant crosslinking of AEM chains irrespective of radiation doses. Oxidative degradation of PP was confirmed by FTIR spectroscopy, which also exhibited absence of any chemical interaction between two constituent polymers. Normalized crystallinity and melting point of compositions, obtained from DSC, decreased with the radiation doses. Furthermore, with the radiation doses clear shifts of maxima of the melting peak towards the lower temperature were observed for neat PP and blends. Thermal stability of PP and blends, as observed by TGA, reduced significantly with irradiation; whereas for AEM, no discernable change was observed. Enhanced chain scissioning of PP in presence of AEM reduced the thermal stability of blends, especially at lower irradiation. This reduction of thermal stability was established by "rule of mixture", applied to the activation energy of thermal degradation. Thus, optimization of radiation doses to prepare TPVs was established.

ZnO as a cheap and effective filler for high breakdown strength elastomers

DEFF Research Database (Denmark)

Yu, Liyun; Skov, Anne Ladegaard

2017-01-01

. In this article, we explore the use of a cheap and abundant metal oxide filler, namely ZnO, as a filler in silicone-based dielectric elastomers. The electro-mechanical properties of the elastomer composites are investigated, and their performance is evaluated by means of figures of merit. Various commercial...

Dielectric elastomers, with very high dielectric permittivity, based on silicone and ionic interpenetrating networks

DEFF Research Database (Denmark)

Yu, Liyun; Madsen, Frederikke Bahrt; Hvilsted, Søren

2015-01-01

permittivity and the Young's modulus of the elastomer. One system that potentially achieves this involves interpenetrating polymer networks (IPNs), based on commercial silicone elastomers and ionic networks from amino- and carboxylic acid-functional silicones. The applicability of these materials as DEs...... are obtained while dielectric breakdown strength and Young's modulus are not compromised. These good overall properties stem from the softening effect and very high permittivity of ionic networks – as high as ε′ = 7500 at 0.1 Hz – while the silicone elastomer part of the IPN provides mechanical integrity...

Propriedades mecânicas e morfologia de blendas de polipropileno com Tpes Morphology and mechanical properties of polypropylenes/Tpes blends

Directory of Open Access Journals (Sweden)

Flávia O. M. S. Abreu

2006-03-01

Full Text Available Blendas de polipropileno e elastômeros termoplásticos (TPEs, estireno-b-butadieno-b-estireno (SBS e estireno-b-etileno-co-butileno-b-estireno(SEBS foram preparadas com o objetivo de avaliar a influência do tipo e da concentração do elastômero nas propriedades mecânicas e na morfologia das blendas. Foram utilizados dois tipos de polipropileno, um homopolímero de propileno (PP-H e um copolímero randômico de propileno-etileno (PP-R, sendo avaliado também o efeito das características da matriz termoplástica. O elastômero termoplástico aumentou a resistência ao impacto do PP, e a variação da rigidez das blendas foi dependente somente da quantidade de TPE adicionada, sendo estas comparativamente mais rígidas que aquelas com igual teor de elastômero convencional, tipo EPDM e EPR. A blenda com melhor balanço rigidez-impacto foi aquela de PP-R com 10% de SEBS. As blendas do copolímero de propileno-etileno com os TPEs apresentaram maior deformação do que aquelas com o homopolímero, devido à natureza menos cristalina da matriz do copolímero de propileno. As blendas tanto do homo quanto do copolímero de propileno com SEBS ficaram mais homogêneas em função da maior afinidade do bloco central poliolefínico EB (etileno-co-butileno do primeiro com a região amorfa da matriz, sendo esta mais significativa no PP-R.Blends of polypropylene and thermoplastic elastomers (TPEs of styrene-butadiene-styrene (SBS and styrene-ethylene-co-butene-styrene (SEBS triblock copolymers were prepared to evaluate the effect of the elastomer and its concentration on the material properties. For this purpose, a polypropylene homopolymer (PP-H and a propylene-ethylene random copolymer (PP-R were used to evaluate the matrix effect on the tensile properties and morphology of the blends. The addition of TPEs to PP promotes increase on impact resistance and the PP-R/SEBS 10%wt blend showed the best balance in stiffness-impact resistance. The morphology of

Graphene and water-based elastomers thin-film composites by dip-moulding.

Science.gov (United States)

Iliut, Maria; Silva, Claudio; Herrick, Scott; McGlothlin, Mark; Vijayaraghavan, Aravind

2016-09-01

Thin-film elastomers (elastic polymers) have a number of technologically significant applications ranging from sportswear to medical devices. In this work, we demonstrate that graphene can be used to reinforce 20 micron thin elastomer films, resulting in over 50% increase in elastic modulus at a very low loading of 0.1 wt%, while also increasing the elongation to failure. This loading is below the percolation threshold for electrical conductivity. We demonstrate composites with both graphene oxide and reduced graphene oxide, the reduction being undertaken in-situ or ex-situ using a biocompatible reducing agent in ascorbic acid. The ultrathin films were cast by dip moulding. The transparency of the elastomer films allows us to use optical microscopy image and confirm the uniform distribution as well as the conformation of the graphene flakes within the composite.

Degradation patterns of silicone-based dielectric elastomers in electrical fields

DEFF Research Database (Denmark)

Yu, Liyun; Madsen, Frederikke Bahrt; Skov, Anne Ladegaard

2017-01-01

. This shortcoming has been attempted optimized through different approaches during recent years. Material optimization with the sole purpose of increasing the dielectric permittivity may lead to the introduction of problematic phenomena such as premature electrical breakdown due to high leakage currents of the thin...... elastomer film. Within this work, electrical breakdown phenomena of various types of permittivity-enhanced silicone elastomers are investigated. Results showed that different types of polymer backbone chemistries lead to differences in electrical breakdown patterns, which were revealed through SEM imaging...

Impact of thermoplastic mask on X-ray surface dose calculated with Monte Carlo code

International Nuclear Information System (INIS)

Zhao Yanqun; Li Jie; Wu Liping; Wang Pei; Lang Jinyi; Wu Dake; Xiao Mingyong

2010-01-01

Objective: To calculate the effects of thermoplastic mask on X-ray surface dose. Methods: The BEAMnrc Monte Carlo Code system, designed especially for computer simulation of radioactive sources, was performed to evaluate the effects of thermoplastic mask on X-ray surface dose.Thermoplastic mask came from our center with a material density of 1.12 g/cm 2 . The masks without holes, with holes size of 0.1 cm x 0.1 cm, and with holes size of 0. 1 cm x 0.2 cm, and masks with different depth (0.12 cm and 0.24 cm) were evaluated separately. For those with holes, the material width between adjacent holes was 0.1 cm. Virtual masks with a material density of 1.38 g/cm 3 without holes with two different depths were also evaluated. Results: Thermoplastic mask affected X-rays surface dose. When using a thermoplastic mask with the depth of 0.24 cm without holes, the surface dose was 74. 9% and 57.0% for those with the density of 1.38 g/cm 3 and 1.12 g/cm 3 respectively. When focusing on the masks with the density of 1.12 g/cm 3 , the surface dose was 41.2% for those with 0.12 cm depth without holes; 57.0% for those with 0. 24 cm depth without holes; 44.5% for those with 0.24 cm depth with holes size of 0.1 cm x 0.2 cm;and 54.1% for those with 0.24 cm depths with holes size of 0.1 cm x 0.1 cm.Conclusions: Using thermoplastic mask during the radiation increases patient surface dose. The severity is relative to the hole size and the depth of thermoplastic mask. The surface dose change should be considered in radiation planning to avoid severe skin reaction. (authors)

Thermal Degradation, Mechanical Properties and Morphology of Wheat Straw Flour Filled Recycled Thermoplastic Composites

Directory of Open Access Journals (Sweden)

Kadir Karakus

2008-01-01

Full Text Available Thermal behaviors of wheat straw flour (WF filled thermoplastic compositeswere measured applying the thermogravimetric analysis and differential scanningcalorimetry. Morphology and mechanical properties were also studied using scanningelectron microscope and universal testing machine, respectively. Presence of WF inthermoplastic matrix reduced the degradation temperature of the composites. One for WFand one for thermoplastics, two main decomposition peaks were observed. Morphologicalstudy showed that addition of coupling agent improved the compatibility between WFs andthermoplastic. WFs were embedded into the thermoplastic matrix indicating improvedadhesion. However, the bonding was not perfect because some debonding can also be seenon the interface of WFs and thermoplastic matrix. In the case of mechanical properties ofWF filled recycled thermoplastic, HDPE and PP based composites provided similar tensileand flexural properties. The addition of coupling agents improved the properties ofthermoplastic composites. MAPE coupling agents performed better in HDPE while MAPPcoupling agents were superior in PP based composites. The composites produced with thecombination of 50-percent mixture of recycled HDPE and PP performed similar with theuse of both coupling agents. All produced composites provided flexural properties requiredby the ASTM standard for polyolefin-based plastic lumber decking boards.

Silicone elastomers with covalently incorporated aromatic voltage stabilisers

DEFF Research Database (Denmark)

A Razak, Aliff Hisyam; Skov, Anne Ladegaard

2017-01-01

to the incorporationof an aromatic voltage stabiliser, were prepared by cross-linking synthesised polydimethylsiloxane–polyphenylmethylsiloxane (PDMS–PPMS) copolymers. PPMS possesses voltage stabilisation capabilitiesbut is immiscible in PDMS, and thus the copolymerisation of the two components was necessary...... forhomogeneity. Concentrations of the voltage stabiliser were varied by changing the molecular weights ofthe PPMS in the copolymer. The developed elastomers were inherently soft with enhanced electricalbreakdown strengths, due to delocalisedp-electrons of the aromatic constituent. An optimumconcentration...

Recycling of ligno-cellulosic and polyethylene wastes from agricultural operations in thermoplastic composites

Science.gov (United States)

In the US, wood plastic composites (WPC) represent one of the successful markets for natural fiber-filled thermoplastic composites. The WPC typically use virgin or recycled thermoplastic as the substrate and wood fiber as the filler. A major application of the WPC is in non-structural building appli...

Motion behaviour of magneto-sensitive elastomers controlled by an external magnetic field for sensor applications

Energy Technology Data Exchange (ETDEWEB)

Volkova, T.I., E-mail: tatiana.volkova@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Böhm, V., E-mail: valter.boehm@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Kaufhold, T., E-mail: tobias.kaufhold@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Popp, J., E-mail: jana.popp@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Becker, F., E-mail: felix.becker@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Borin, D.Yu., E-mail: dmitry.borin@tu-dresden.de [Technische Universität Dresden, Magnetofluiddynamics, Measuring and Automation Technology, D-01062 Dresden (Germany); Stepanov, G.V., E-mail: gstepanov@mail.ru [State Institute of Chemistry and Technology of Organoelement Compounds, 105118 Moscow (Russian Federation); Zimmermann, K., E-mail: klaus.zimmermann@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany)

2017-06-01

The development of sensor systems with a complex adaptive regulation of the operating sensitivity and behaviour is an actual scientific and technical challenge. Smart materials like magneto-sensitive elastomers (MSE) are seen as one potential solution for this problem, since their mechanical properties may be controlled by external magnetic fields. The present paper deals with the investigation of elastic and damping properties of MSE containing magnetically soft particles under the influence of a uniform magnetic field. Based on the measurement of the first eigenfrequency of free bending vibrations of a fixed beam, the effective Young's modulus is evaluated theoretically and also numerically using Finite Element Method. It is shown that this parameter, as well as the first eigenfrequency of the beam, increases monotonically with the magnitude of the applied magnetic field. The results are aimed to develop an acceleration sensor with adaptive magnetically controllable sensitivity range for the detection of external mechanical stimuli of the environment. - Highlights: • The motion behaviour of magneto-sensitive elastomers (MSE) with magnetically soft particles is investigated. • The first eigenfrequency of free bending vibrations of an MSE beam can be controlled by a uniform magnetic field. • Based on the experimental results, the effective Young's modulus of the system is evaluated theoretically and numerically. • The Young's modulus increases monotonically with the magnitude of the applied magnetic field. • The controlled mechanical compliance of MSE may be used for development of sensor systems with adaptive sensitivity range.

Effects of thermo-order-mechanical coupling on band structures in liquid crystal nematic elastomer porous phononic crystals.

Science.gov (United States)

Yang, Shuai; Liu, Ying

2018-08-01

Liquid crystal nematic elastomers are one kind of smart anisotropic and viscoelastic solids simultaneously combing the properties of rubber and liquid crystals, which is thermal sensitivity. In this paper, the wave dispersion in a liquid crystal nematic elastomer porous phononic crystal subjected to an external thermal stimulus is theoretically investigated. Firstly, an energy function is proposed to determine thermo-induced deformation in NE periodic structures. Based on this function, thermo-induced band variation in liquid crystal nematic elastomer porous phononic crystals is investigated in detail. The results show that when liquid crystal elastomer changes from nematic state to isotropic state due to the variation of the temperature, the absolute band gaps at different bands are opened or closed. There exists a threshold temperature above which the absolute band gaps are opened or closed. Larger porosity benefits the opening of the absolute band gaps. The deviation of director from the structural symmetry axis is advantageous for the absolute band gap opening in nematic state whist constrains the absolute band gap opening in isotropic state. The combination effect of temperature and director orientation provides an added degree of freedom in the intelligent tuning of the absolute band gaps in phononic crystals. Copyright © 2018 Elsevier B.V. All rights reserved.

Electrical behaviour of a silicone elastomer under simulated space environment

International Nuclear Information System (INIS)

Roggero, A; Dantras, E; Paulmier, T; Rejsek-Riba, V; Tonon, C; Dagras, S; Balcon, N; Payan, D

2015-01-01

The electrical behavior of a space-used silicone elastomer was characterized using surface potential decay and dynamic dielectric spectroscopy techniques. In both cases, the dielectric manifestation of the glass transition (dipole orientation) and a charge transport phenomenon were observed. An unexpected linear increase of the surface potential with temperature was observed around T g in thermally-stimulated potential decay experiments, due to molecular mobility limiting dipolar orientation in one hand, and 3D thermal expansion reducing the materials capacitance in the other hand. At higher temperatures, the charge transport process, believed to be thermally activated electron hopping with an activation energy of about 0.4 eV, was studied with and without the silica and iron oxide fillers present in the commercial material. These fillers were found to play a preponderant role in the low-frequency electrical conductivity of this silicone elastomer, probably through a Maxwell–Wagner–Sillars relaxation phenomenon. (paper)

Dynamic- and Thermo- mechanical Analysis of Inorganic Nanotubes/elastomer Composites

Directory of Open Access Journals (Sweden)

Armin FUITH

2011-10-01

Full Text Available We present dynamic mechanical analysis (DMA and thermomechanical analysis (TMA measurements of a new type of polyurea elastomer nanocomposites based on inorganic MoS2 nanotubes and Mo6S2I8 nanowires. The addition of a small amount of nanoparticles (<1 wt-% leads to an increase of the glass transition temperature Tg as compared to the pure elastomeric matrix. A second peak observed in tand in the pure and mixed elastomer is attributed to a second glass transition occurring in regions near the hard nanodomains of the microphase separated polyurea system. It is also found that the small amount of nanoparticles leads to an increase in the Young´s modulus of up to 15 % in the whole measured temperature range (from -130 °C to 20 °C. The thermal expansion of doped samples is considerably larger above Tg. Below Tg, this difference vanishes completely. A very similar behaviour was also found in measurements of polyisoprene/multiwall carbon nanotube (MWCNT composites.

Polydopamine-Coated Main-Chain Liquid Crystal Elastomer as Optically Driven Artificial Muscle.

Science.gov (United States)

Tian, Hongmiao; Wang, Zhijian; Chen, Yilong; Shao, Jinyou; Gao, Tong; Cai, Shengqiang

2018-03-07

Optically driven active materials have received much attention because their deformation and motion can be controlled remotely, instantly, and precisely in a contactless way. In this study, we investigated an optically actuated elastomer with rapid response: polydopamine (PDA)-coated liquid crystal elastomer (LCE). Because of the photothermal effect of PDA coating and thermal responsiveness of LCE, the elastomer film contracted significantly with near-infrared (NIR) irradiation. With a fixed strain, light-induced actuating stress in the film could be as large as 1.5 MPa, significantly higher than the maximum stress generated by most mammalian skeletal muscle (0.35 MPa). The PDA-coated LCE films could also bend or roll up by surface scanning of an NIR laser. The response time of the film to light exposure could be as short as 1/10 of a second, comparable to or even faster than that of mammalian skeletal muscle. Using the PDA-coated LCE film, we designed and fabricated a prototype of robotic swimmer that was able to swim near the water-air interface by performing "swimming strokes" through reversible bending and unbending motions induced and controlled by an NIR laser. The results presented in this study clearly demonstrated that PDA-coated LCE is a promising optically driven artificial muscle, which may have great potential for applications of soft robotics and optomechanical coupling devices.

High performance thermoplastics - A review of neat resin and composite properties

Science.gov (United States)

Johnston, Norman J.; Hergenrother, Paul M.

1987-01-01

A review was made of the principal thermoplastics used to fabricate high performance composites. Neat resin tensile and fracture toughness properties, glass transition temperatures (Tg), crystalline melt temperatures (Tm) and approximate processing conditions are presented. Mechanical properties of carbon fiber composites made from many of these thermoplastics are given, including flexural, longitudinal tensile, transverse tensile and in-plane shear properties as well as short beam shear and compressive strengths and interlaminar fracture toughness.

Polycyanurates and Polycarbonates Based on Eugenol: Alternatives to Thermosetting and Thermoplastic Polymers Based on Bisphenol A

Science.gov (United States)

2014-08-14

to 5a. CONTRACT NUMBER In-House Thermosetting and Thermoplastic Polymers based on Bisphenol A 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...Francisco, CA, 14 August 2014. PA#14389 14. ABSTRACT Polycyanurate thermosetting networks, polycarbonate thermoplastics, and homogenous polycarbonate...ON EUGENOL: ALTERNATIVES TO THERMOSETTING AND THERMOPLASTIC POLYMES BASED ON BISPHENOL A 14 August 2014 Andrew J. Guenthner1, Benjamin G. Harvey2

Design of Elastomer Structure to Facilitate Incorporation of Expanded Graphite in Silicones Without Compromising Electromechanical Integrity

DEFF Research Database (Denmark)

Hassouneh, Suzan Sager; Daugaard, Anders Egede; Skov, Anne Ladegaard

2015-01-01

The development of elastomer materials with a high dielectric permittivity has attracted increased interest over the past years due to their use in, for example, dielectric elastomers. For this particular use, both the electrically insulating properties - as well as the mechanical properties......-functional crosslinker, which allows for development of a suitable network matrix. The dielectric permittivity was increased by almost a factor of 4 compared to a benchmark silicone elastomer....

Diffraction from relief gratings on a biomimetic elastomer cast

International Nuclear Information System (INIS)

Guerrero, Raphael A.; Aranas, Erika B.

2010-01-01

Biomimetic optical elements combine the optimized designs of nature with the versatility of materials engineering. We employ a beetle carapace as the template for fabricating relief gratings on an elastomer substrate. Biological surface features are successfully replicated by a direct casting procedure. Far-field diffraction effects are discussed in terms of the Fraunhofer approximation in Fourier space.

Hemispherical breathing mode speaker using a dielectric elastomer actuator.

Science.gov (United States)

Hosoya, Naoki; Baba, Shun; Maeda, Shingo

2015-10-01

Although indoor acoustic characteristics should ideally be assessed by measuring the reverberation time using a point sound source, a regular polyhedron loudspeaker, which has multiple loudspeakers on a chassis, is typically used. However, such a configuration is not a point sound source if the size of the loudspeaker is large relative to the target sound field. This study investigates a small lightweight loudspeaker using a dielectric elastomer actuator vibrating in the breathing mode (the pulsating mode such as the expansion and contraction of a balloon). Acoustic testing with regard to repeatability, sound pressure, vibration mode profiles, and acoustic radiation patterns indicate that dielectric elastomer loudspeakers may be feasible.

Mechanical Properties of Isotactic Polypropylene Modified with Thermoplastic Potato Starch

Science.gov (United States)

Knitter, M.; Dobrzyńska-Mizera, M.

2015-05-01

In this paper selected mechanical properties of isotactic polypropylene (iPP) modified with potato starch have been presented. Thermoplastic starch (TPS) used as a modifier in the study was produced from potato starch modified with glycerol. Isotactic polypropylene/thermoplastic potato starch composites (iPP/TPS) that contained 10, 30, 50 wt.% of modified starch were examined using dynamic mechanical-thermal analysis, static tensile, Brinell hardness, and Charpy impact test. The studies indicated a distinct influence of a filler content on the mechanical properties of composites in comparison with non-modified polypropylene.

Prediction of wrinklings and porosities of thermoplastic composits after thermostamping

Science.gov (United States)

Hamila, Nahiene; Guzman-Maldonado, Eduardo; Xiong, Hu; Wang, Peng; Boisse, Philippe; Bikard, Jerome

2018-05-01

During thermoforming process, the consolidation deformation mode of thermoplastic prepregs is one of the key deformation modes especially in the consolidation step, where the two resin flow phenomena: resin percolation and transverse squeeze flow, play an important role. This occurs a viscosity behavior for consolidation mode. Based on a visco-hyper-elastic model for the characterization of thermoplastic prepregs proposed by Guzman, which involves different independent modes of deformation: elongation mode, bending mode with thermo-dependent, and viscoelastic in-plan shearing mode with thermo-dependent, a viscoelastic model completed with consolidation behavior will be presented in this paper. A completed three-dimensional mechanical behavior with compaction effect for thermoplastic pre-impregnated composites is constituted, and the associated parameters are identified by compaction test. Moreover, a seven-node prismatic solid-shell finite element approach is used for the forming simulation. To subdue transverse shear locking, an intermediate material frame related to the element sides is introduced in order to fix nodal transverse shear strain components. Indeed, the enhanced assumed strain method and a reduced integration scheme are combined offering a linear varying strain field along the thickness direction to circumvent thickness locking, and an hourglass stabilization procedure is employed in order to correct the element's rank deficiency for pinching. An additional node is added at the center providing a quadratic interpolation of the displacement in the thickness direction. The predominance of this element is the ability of three dimensional analysis, especially for the transverse stress existence through the thickness of material, which is essential for the consolidation modelling. Finally, an intimate contact model is employed to predict the evolution of the consolidation which permits the microstructure prediction of void presented through the prepreg

Characterization of thermoplastic composites for hot stamp forming

NARCIS (Netherlands)

Rietman, Bert; Grouve, Wouter; Akkerman, Remko

2014-01-01

This paper describes state-of-the-art characterization methods for thermoplastic composites at high processing temperature and provides a few examples of application in simulations of the hot stamp forming process.

EXPERIMENTAL INVESTIGATION OF THE ADHESIVE CONTACT WITH ELASTOMERS: EFFECT OF SURFACE ROUGHNESS

Directory of Open Access Journals (Sweden)

Lars Voll

2015-04-01

Full Text Available Adhesion between an elastomer and a steel indenter was studied experimentally and described with an analytical model. Cylindrical indenters having different roughness were brought into contact with an elastomer with various normal forces. After a “holding time”, the indenter was pulled with a constant velocity, which was the same in all experiments. We have studied the regime of relatively small initial normal loadings, large holding times and relatively large pulling velocities, so that the adhesive force did not depend on the holding time but did depend on the initially applied normal force and was approximately proportional to the pulling velocity. Under these conditions, we found that the adhesive force is inversely proportional to the roughness and proportional to the normal force. For the theoretical analysis, we used a previously published MDR-based model.

Use of Melt Flow Rate Test in Reliability Study of Thermoplastic Encapsulation Materials in Photovoltaic Modules

Energy Technology Data Exchange (ETDEWEB)

Moseley, J.; Miller, D.; Shah, Q.-U.-A. S. J.; Sakurai, K.; Kempe, M.; Tamizhmani, G.; Kurtz, S.

2011-10-01

Use of thermoplastic materials as encapsulants in photovoltaic (PV) modules presents a potential concern in terms of high temperature creep, which should be evaluated before thermoplastics are qualified for use in the field. Historically, the issue of creep has been avoided by using thermosetting polymers as encapsulants, such as crosslinked ethylene-co-vinyl acetate (EVA). Because they lack crosslinked networks, however, thermoplastics may be subject to phase transitions and visco-elastic flow at the temperatures and mechanical stresses encountered by modules in the field, creating the potential for a number of reliability and safety issues. Thermoplastic materials investigated in this study include PV-grade uncured-EVA (without curing agents and therefore not crosslinked); polyvinyl butyral (PVB); thermoplastic polyurethane (TPU); and three polyolefins (PO), which have been proposed for use as PV encapsulation. Two approaches were used to evaluate the performance of these materials as encapsulants: module-level testing and a material-level testing.

Experimental study on behaviors of dielectric elastomer based on acrylonitrile butadiene rubber

Science.gov (United States)

An, Kuangjun; Chuc, Nguyen Huu; Kwon, Hyeok Yong; Phuc, Vuong Hong; Koo, Jachoon; Lee, Youngkwan; Nam, Jaedo; Choi, Hyouk Ryeol

2010-04-01

Previously, the dielectric elastomer based on Acrylonitrile Butadiene Rubber (NBR), called synthetic elastomer has been reported by our group. It has the advantages that its characteristics can be modified according to the requirements of performances, and thus, it is applicable to a wide variety of applications. In this paper, we address the effects of additives and vulcanization conditions on the overall performance of synthetic elastomer. In the present work, factors to have effects on the performances are extracted, e.g additives such as dioctyl phthalate (DOP), barium titanium dioxide (BaTiO3) and vulcanization conditions such as dicumyl peroxide (DCP), cross-linking times. Also, it is described how the performances can be optimized by using DOE (Design of Experiments) technique and experimental results are analyzed by ANOVA (Analysis of variance).

Photoinitiated grafting of porous polymer monoliths and thermoplastic polymers for microfluidic devices

Science.gov (United States)

Frechet, Jean M. J. [Oakland, CA; Svec, Frantisek [Alameda, CA; Rohr, Thomas [Leiden, NL

2008-10-07

A microfluidic device preferably made of a thermoplastic polymer that includes a channel or a multiplicity of channels whose surfaces are modified by photografting. The device further includes a porous polymer monolith prepared via UV initiated polymerization within the channel, and functionalization of the pore surface of the monolith using photografting. Processes for making such surface modifications of thermoplastic polymers and porous polymer monoliths are set forth.

One-pot synthesis of thermoplastic mixed paramylon esters using trifluoroacetic anhydride.

Science.gov (United States)

Shibakami, Motonari; Tsubouchi, Gen; Sohma, Mitsugu; Hayashi, Masahiro

2015-03-30

Mixed paramylon esters prepared from paramylon (a storage polysaccharide of Euglena), acetic acid, and a long-chain fatty acid by one-pot synthesis using trifluoroacetic anhydride as a promoter and solvent were shown to have thermoplasticity. Size exclusion chromatography indicated that the mixed paramylon esters had a weight average molecular weight of approximately 4.9-6.7×10(5). Thermal analysis showed that these esters were stable in terms of the glass transition temperature (>90°C) and 5% weight loss temperature (>320°C). The degree of substitution of the long alkyl chain group, a dominant factor determining thermoplasticity, was controlled by tuning the feed molar ratio of acetic acid and long-chain fatty acid to paramylon. These results implied that the one-pot synthesis is useful for preparing structurally-well defined thermoplastic mixed paramylon esters with high molecular weight. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optimisation of Silicone-based Dielectric Elastomer Transducers by Means of Block Copolymers - Synthesis and Compounding

DEFF Research Database (Denmark)

A Razak, Aliff Hisyam

through the use of a multi-walled carbon nanotube (MWCNT) in a PDMS-PEG matrix as a compliant electrode of dielectric elastomers. The conductive PDMS-PEG copolymer was incorporated with surface-treated MWCNT, in order to obtain highly conductive elastomer. The prepared sample with 4 parts per hundred...... enhancing the electrical breakdown strength of silicone by using an aromatic voltage stabiliser. Here, polyphenylmethylsiloxane (PPMS), which contained aromatic voltage stabilisers, was bonded covalently to PDMS through a hydrosilylation reaction obtaining PDMS-PPMS copolymers. The synthesised copolymers...

Chemicals having estrogenic activity can be released from some bisphenol A-free, hard and clear, thermoplastic resins.

Science.gov (United States)

Bittner, George D; Denison, Michael S; Yang, Chun Z; Stoner, Matthew A; He, Guochun

2014-12-04

Chemicals that have estrogenic activity (EA) can potentially cause adverse health effects in mammals including humans, sometimes at low doses in fetal through juvenile stages with effects detected in adults. Polycarbonate (PC) thermoplastic resins made from bisphenol A (BPA), a chemical that has EA, are now often avoided in products used by babies. Other BPA-free thermoplastic resins, some hypothesized or advertised to be EA-free, are replacing PC resins used to make reusable hard and clear thermoplastic products such as baby bottles. We used two very sensitive and accurate in vitro assays (MCF-7 and BG1Luc human cell lines) to quantify the EA of chemicals leached into ethanol or water/saline extracts of fourteen unstressed or stressed (autoclaving, microwaving, UV radiation) thermoplastic resins. Estrogen receptor (ER)-dependent agonist responses were confirmed by their inhibition with the ER antagonist ICI 182,780. Our data showed that some (4/14) unstressed and stressed BPA-free thermoplastic resins leached chemicals having significant levels of EA, including one polystyrene (PS), and three Tritan™ resins, the latter reportedly EA-free. Exposure to UV radiation in natural sunlight resulted in an increased release of EA from Tritan™ resins. Triphenyl-phosphate (TPP), an additive used to manufacture some thermoplastic resins such as Tritan™, exhibited EA in both MCF-7 and BG1Luc assays. Ten unstressed or stressed glycol-modified polyethylene terephthalate (PETG), cyclic olefin polymer (COP) or copolymer (COC) thermoplastic resins did not release chemicals with detectable EA under any test condition. This hazard survey study assessed the release of chemicals exhibiting EA as detected by two sensitive, widely used and accepted, human cell line in vitro assays. Four PC replacement resins (Tritan™ and PS) released chemicals having EA. However, ten other PC-replacement resins did not leach chemicals having EA (EA-free-resins). These results indicate that PC

Viscoelastic and photo-actuation studies of composites based on polystyrene-grafted carbon nanotubes and styrene-b-isoprene-b-styrene block copolymer

Czech Academy of Sciences Publication Activity Database

Ilčíková, M.; Mrlík, M.; Sedláček, T.; Chorvát, D.; Krupa, I.; Šlouf, Miroslav; Koynov, K.; Mosnáček, J.

2014-01-01

Roč. 55, č. 1 (2014), s. 211-218 ISSN 0032-3861 R&D Projects: GA TA ČR TE01020118 Institutional support: RVO:61389013 Keywords : thermoplastic elastomers * grafting from surface * smart materials Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.562, year: 2014

Thermoplastic starch materials prepared from rice starch; Preparacao e caracterizacao de materiais termoplasticos preparados a partir de amido de arroz

Energy Technology Data Exchange (ETDEWEB)

Pontes, Barbara R.B.; Curvelo, Antonio A.S., E-mail: barbarapont@gmail.co [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica

2009-07-01

Rice starch is a source still little studied for the preparation of thermoplastic materials. However, its characteristics, such as the presence of proteins, fats and fibers may turn into thermoplastics with a better performance. The present study intends the evaluation of the viability of making starch thermoplastic from rice starch and glycerol as plasticizer. The results of X-ray diffraction and scanning electronic microscopy demonstrate the thermoplastic acquisition. The increase of plasticizer content brings on more hydrophilic thermoplastics with less resistance to tension and elongation at break. (author)

Tensile and impact properties of three-component PP/wood/elastomer composites

Directory of Open Access Journals (Sweden)

B. Pukanszky

2012-03-01

Full Text Available Polypropylene (PP was reinforced with wood flour and impact modified with elastomers to increase stiffness and impact resistance simultaneously. Elastomer content changed in four (0, 5, 10 and 20 wt%, while that of wood content in seven steps, the latter from 0 to 60 wt% in 10 wt% steps. Structure and adhesion were controlled by the addition of functionalized (maleated polymers. Composites were homogenized in a twin-screw extruder and then injection molded to tensile bars. Fracture resistance was characterized by standard and instrumented impact tests. The results showed that the components are dispersed independently of each other even when a functionalized elastomer is used for impact modification, at least under the conditions of this study. Impact resistance does not change much as a function of wood content in PP/wood composites, but decreases drastically from the very high level of the PP/elastomer blend to almost the same value obtained without impact modifier in the three-component materials. Increasing stiffness and fiber related local deformation processes led to small fracture toughness at large wood content. Micromechanical deformation processes depend mainly on the strength of PP/wood interaction; debonding and pull-out take place at poor adhesion, while fiber fracture dominates when adhesion is strong. Composites with sufficiently large impact resistance cannot be prepared in the usual range of wood contents (50–60 wt%.

Dielectric elastomer actuators using Slide-Ring Material® with increased permittivity

International Nuclear Information System (INIS)

Tsuchitani, Shigeki; Miki, Hirofumi; Sunahara, Tokiharu

2015-01-01

The inclusion of high permittivity nanoparticles in elastomeric materials for dielectric elastomer actuators (DEAs) is one promising method to achieve large strain at relatively low applied voltages. However, the addition of these nanoparticles tends to increase the stiffness of the elastomer and disturbs the actuation of the DEA. This is attributed to restriction of the chain motion in the elastomer by the nanoparticles. Slide-Ring Material ® (SRM) is a cross-linked polymeric material with freely movable cross-linking sites. The internal stresses in this structure are dramatically homogenized by the pulley effect; therefore, the restriction of chain motion due to the nanoparticles is expected to be significantly reduced. We have employed SRM as a host elastomer for a DEA with the addition of ferroelectric BaTiO 3 (BT) nanoparticles. The effects of BT addition on the permittivity, stiffness and viscosity of the SRM–BT nanocomposites, and the actuation strain of DEAs using SRM were evaluated. The permittivity of the nanocomposites increased linearly with the concentration of BT and reached 3.6 times that for pure SRM at 50 wt%. The elastic modulus and the viscosity remained almost constant up to 20 wt% and then decreased above this concentration. The actuation strain of a planar actuator using SRM and 50 wt% BT was four times larger than that of the DEA with pure SRM. (paper)

Inverse grey-box model-based control of a dielectric elastomer actuator

DEFF Research Database (Denmark)

Jones, Richard William; Sarban, Rahimullah

2012-01-01

control performance across the operating range of the DE actuator, a gain scheduling term, which linearizes the operating characteristics of the tubular dielectric elastomer actuator, is developed and implemented in series with the IMC controller. The IMC-based approach is investigated for servo control......An accurate physical-based electromechanical model of a commercially available tubular dielectric elastomer (DE) actuator has been developed and validated. In this contribution, the use of the physical-based electromechanical model to formulate a model-based controller is examined. The choice...... of control scheme was dictated by the desire for transparency in both controller design and operation. The internal model control (IMC) approach was chosen. In this particular application, the inverse of the linearized form of the grey-box model is used to formulate the IMC controller. To ensure consistent...

Pyrolysis characteristics of typical biomass thermoplastic composites

Directory of Open Access Journals (Sweden)

Hongzhen Cai

Full Text Available The biomass thermoplastic composites were prepared by extrusion molding method with poplar flour, rice husk, cotton stalk and corn stalk. The thermo gravimetric analyzer (TGA has also been used for evaluating the pyrolysis process of the composites. The results showed that the pyrolysis process mainly consists of two stages: biomass pyrolysis and the plastic pyrolysis. The increase of biomass content in the composite raised the first stage pyrolysis peak temperature. However, the carbon residue was reduced and the pyrolysis efficiency was better because of synergistic effect of biomass and plastic. The composite with different kinds of biomass have similar pyrolysis process, and the pyrolysis efficiency of the composite with corn stalk was best. The calcium carbonate could inhibit pyrolysis process and increase the first stage pyrolysis peak temperature and carbon residue as a filling material of the composite. Keywords: Biomass thermoplastic composite, Calcium carbonate, Pyrolysis characteristic

Experimental characterisation of Lamb wave propagation through thermoplastic composite ultrasonic welds

NARCIS (Netherlands)

Viegas Ochoa de Carvalho, Pedro; Fernandez Villegas, I.; Groves, R.M.; Benedictus, R.

2016-01-01

Ultrasonic welding is a very promising technique for joining thermoplastic composite (TpC) components in aircraft primary structures [1, 2]. The potential introduction of new lightweight structures in civil aviation has been driving the change towards condition-based maintenance (CBM) as an

Monitoring the petroleum bitumen characteristics changes during their interaction with the polymers

Science.gov (United States)

Belyaev, P. S.; Mishchenko, S. V.; Belyaev, V. P.; Frolov, V. A.

2017-08-01

The subject of the study is the characteristics (penetration, softening temperature, ductility and elasticity) of a road binder based on petroleum bitumen. The work purpose is to monitor the changes in the characteristics of petroleum bitumen when it interacting with polymers: thermoplastic elastomer, low-density polyethylene, including the adhesive additive presence. To carry out the research a special laboratory facility was designed and manufactured with two blade mixers providing intensive turbulent mixing and the possibility to effect on the transition process of combining the components in a polymer-bitumen binder. To construct a mathematical model of the polymer-bitumen binder characteristics dependence from the composition, methods of statistical experiments planning were used. The possibility of the expensive thermoplastic elastomers replacement with polyethylene is established while maintaining acceptable polymer-bitumen binder quality parameters. The obtained results are proposed for use in road construction. They allow to reduce the roads construction cost with solving the problem of recycling long-term waste packaging from polyethylene.

An autonomously electrically self-healing liquid metal-elastomer composite for robust soft-matter robotics and electronics.

Science.gov (United States)

Markvicka, Eric J; Bartlett, Michael D; Huang, Xiaonan; Majidi, Carmel

2018-07-01

Large-area stretchable electronics are critical for progress in wearable computing, soft robotics and inflatable structures. Recent efforts have focused on engineering electronics from soft materials-elastomers, polyelectrolyte gels and liquid metal. While these materials enable elastic compliance and deformability, they are vulnerable to tearing, puncture and other mechanical damage modes that cause electrical failure. Here, we introduce a material architecture for soft and highly deformable circuit interconnects that are electromechanically stable under typical loading conditions, while exhibiting uncompromising resilience to mechanical damage. The material is composed of liquid metal droplets suspended in a soft elastomer; when damaged, the droplets rupture to form new connections with neighbours and re-route electrical signals without interruption. Since self-healing occurs spontaneously, these materials do not require manual repair or external heat. We demonstrate this unprecedented electronic robustness in a self-repairing digital counter and self-healing soft robotic quadruped that continue to function after significant damage.

Multiple-objective optimization in precision laser cutting of different thermoplastics

Science.gov (United States)

Tamrin, K. F.; Nukman, Y.; Choudhury, I. A.; Shirley, S.

2015-04-01

Thermoplastics are increasingly being used in biomedical, automotive and electronics industries due to their excellent physical and chemical properties. Due to the localized and non-contact process, use of lasers for cutting could result in precise cut with small heat-affected zone (HAZ). Precision laser cutting involving various materials is important in high-volume manufacturing processes to minimize operational cost, error reduction and improve product quality. This study uses grey relational analysis to determine a single optimized set of cutting parameters for three different thermoplastics. The set of the optimized processing parameters is determined based on the highest relational grade and was found at low laser power (200 W), high cutting speed (0.4 m/min) and low compressed air pressure (2.5 bar). The result matches with the objective set in the present study. Analysis of variance (ANOVA) is then carried out to ascertain the relative influence of process parameters on the cutting characteristics. It was found that the laser power has dominant effect on HAZ for all thermoplastics.

In situ multi-axial loading frame to probe elastomers using X-ray scattering.

Science.gov (United States)

Pannier, Yannick; Proudhon, Henry; Mocuta, Cristian; Thiaudière, Dominique; Cantournet, Sabine

2011-11-01

An in situ tensile-shear loading device has been designed to study elastomer crystallization using synchrotron X-ray scattering at the Synchrotron Soleil on the DiffAbs beamline. Elastomer tape specimens of thickness 2 mm can be elongated by up to 500% in the longitudinal direction and sheared by up to 200% in the transverse direction. The device is fully automated and plugged into the TANGO control system of the beamline allowing synchronization between acquisition and loading sequences. Experimental results revealing the evolution of crystallization peaks under load are presented for several tension/shear loading sequences.

The shape-memory effect in ionic elastomers: fixation through ionic interactions.

Science.gov (United States)

González-Jiménez, Antonio; Malmierca, Marta A; Bernal-Ortega, Pilar; Posadas, Pilar; Pérez-Aparicio, Roberto; Marcos-Fernández, Ángel; Mather, Patrick T; Valentín, Juan L

2017-04-19

Shape-memory elastomers based on a commercial rubber cross-linked by both ionic and covalent bonds have been developed. The elastomeric matrix was a carboxylated nitrile rubber (XNBR) vulcanized with magnesium oxide (MgO) providing ionic interactions that form hierarchical structures. The so-named ionic transition is used as the unique thermal transition responsible for the shape-memory effect (SME) in these elastomers. These ionic interactions fix the temporary shape due to their behavior as dynamic cross-links with temperature changes. Covalent cross-links were incorporated with the addition of different proportions of dicumyl peroxide (DCP) to the ionic elastomer to establish and recover the permanent shape. In this article, the SME was modulated by modifying the degree of covalent cross-linking, while keeping the ionic contribution constant. In addition, different programming parameters, such as deformation temperature, heating/cooling rate, loading/unloading rate and percentage of tensile strain, were evaluated for their effects on shape-memory behavior.

Modeling shape selection of buckled dielectric elastomers

Science.gov (United States)

Langham, Jacob; Bense, Hadrien; Barkley, Dwight

2018-02-01

A dielectric elastomer whose edges are held fixed will buckle, given a sufficiently applied voltage, resulting in a nontrivial out-of-plane deformation. We study this situation numerically using a nonlinear elastic model which decouples two of the principal electrostatic stresses acting on an elastomer: normal pressure due to the mutual attraction of oppositely charged electrodes and tangential shear ("fringing") due to repulsion of like charges at the electrode edges. These enter via physically simplified boundary conditions that are applied in a fixed reference domain using a nondimensional approach. The method is valid for small to moderate strains and is straightforward to implement in a generic nonlinear elasticity code. We validate the model by directly comparing the simulated equilibrium shapes with the experiment. For circular electrodes which buckle axisymetrically, the shape of the deflection profile is captured. Annular electrodes of different widths produce azimuthal ripples with wavelengths that match our simulations. In this case, it is essential to compute multiple equilibria because the first model solution obtained by the nonlinear solver (Newton's method) is often not the energetically favored state. We address this using a numerical technique known as "deflation." Finally, we observe the large number of different solutions that may be obtained for the case of a long rectangular strip.

The effect of cocoa (Theobroma cacao L on the basic color stability of thermoplastic nylon resin dentures

Directory of Open Access Journals (Sweden)

Amiyatun Naini

2011-11-01

Full Text Available Nylon thermoplastic resin is material of choice for the making of flexible. This denture do not use wire retention, but has the physical properties of water absorption. In the oral cavity, it will always be in contact with food and beverages consumed. One of the foods that are consumed by the public is chocolate. This study aimed to determine the effect of cocoa (Theobroma cacao L on color stability of the thermoplastic nylon denture base. The study sample was thermoplastic nylon (valplast with a size of 10x10x2 mm soaked in the chocolate solution for 7 and 14 days. As the control, the sample soaked with distilled water. The color testing stability used was densitometer. There were significant differences between the control group (distilled water and the chocolate solution. This was due to dissolved components/tannin having a capillary flow diffusion into thermoplastic nylons that causing discoloration. The conclusion of this study, there was the effect of cocoa (Theobroma cacao L against the color stability of the nylon thermoplastic denture base. The longer time of immersion of nylon thermoplastic the greater the change in color.

Numerical study of liquid crystal elastomers by a mixed finite element method

KAUST Repository

LUO, C.

2011-08-22

Liquid crystal elastomers present features not found in ordinary elastic materials, such as semi-soft elasticity and the related stripe domain phenomenon. In this paper, the two-dimensional Bladon-Terentjev-Warner model and the one-constant Oseen-Frank energy expression are combined to study the liquid crystal elastomer. We also impose two material constraints, the incompressibility of the elastomer and the unit director norm of the liquid crystal. We prove existence of minimiser of the energy for the proposed model. Next we formulate the discrete model, and also prove that it possesses a minimiser of the energy. The inf-sup values of the discrete linearised system are then related to the smallest singular values of certain matrices. Next the existence and uniqueness of the Lagrange multipliers associated with the two material constraints are proved under the assumption that the inf-sup conditions hold. Finally numerical simulations of the clamped-pulling experiment are presented for elastomer samples with aspect ratio 1 or 3. The semi-soft elasticity is successfully recovered in both cases. The stripe domain phenomenon, however, is not observed, which might be due to the relative coarse mesh employed in the numerical experiment. Possible improvements are discussed that might lead to the recovery of the stripe domain phenomenon. © Copyright Cambridge University Press 2011.

Preparation of magnetorheological elastomers and their slip-free characterization by means of parallel-plate rotational rheometry

Science.gov (United States)

Walter, Bastian L.; Pelteret, Jean-Paul; Kaschta, Joachim; Schubert, Dirk W.; Steinmann, Paul

2017-08-01

A systematic study is presented to highlight a methodology of sample preparation and subsequent slip-free characterization of magnetorheological (MR) elastomers in parallel-plate rotational rheometry. Focusing on the magnetic field-dependent nonlinear viscoelastic behavior an array of oscillatory strain sweep measurements is conducted with samples cured within the rheometer. The examined nonlinear material response (i.e. the amplitude dependence of the storage and loss moduli) as a function of the applied magnetic field is found to be qualitatively similar to the amplitude dependence of particle reinforced elastomers (i.e. the Payne effect). Therefore, the experimental data (both moduli) is decomposed similar to that for reinforced elastomers and a phenomenological model is formulated for both the storage and loss modulus to account for the physical mechanisms governing the nonlinear material characteristics. Parameter identification suggests that the material response at low magnetic fields is dominated by the polymeric network whereas the strong magneto-reinforced microstructure governs the linear and nonlinear viscoelastic behavior at high magnetic fields. The overall experimental outcome further suggests that the underlying concept of the phenomenological model for particle reinforced elastomers (i.e. destruction and reformation of the filler network) can be transfered to MR materials. Consequently, the proposed phenomenological model can be applied to quantify and further analyze the nonlinear response characteristics of MR elastomers (i.e. the amplitude dependence of the storage and loss modulus as a function of the applied magnetic field) that is closely linked to microstructural changes of the magnetizable particle network.

Cross-Linked Liquid Crystalline Systems From Rigid Polymer Networks to Elastomers

CERN Document Server

Broer, Dirk

2011-01-01

With rapidly expanding interest in liquid crystalline polymers and elastomers among the liquid crystal community, researchers are currently exploring the wide range of possible application areas for these unique materials, including optical elements on displays, tunable lasers, strain gauges, micro-structures, and artificial muscles. Written by respected scientists from academia and industry around the world, who are not only active in the field but also well-known in more traditional areas of research, "Cross-Linked Liquid Crystalline Systems: From Rigid Polymer Networks to Elastomers&qu

Portable Device Slices Thermoplastic Prepregs

Science.gov (United States)

Taylor, Beverly A.; Boston, Morton W.; Wilson, Maywood L.

1993-01-01

Prepreg slitter designed to slit various widths rapidly by use of slicing bar holding several blades, each capable of slicing strip of preset width in single pass. Produces material evenly sliced and does not contain jagged edges. Used for various applications in such batch processes involving composite materials as press molding and autoclaving, and in such continuous processes as pultrusion. Useful to all manufacturers of thermoplastic composites, and in slicing B-staged thermoset composites.

21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.

Science.gov (United States)

2010-04-01

... parts by weight of a grafted rubber consisting of (i) 8-12 parts of butadiene/styrene elastomer... limitations are determined by an infrared spectro-photo-metric method titled “Infrared Spectro-photo-metric...

Effects of Hypervelocity Impacts on Silicone Elastomer Seals and Mating Aluminum Surfaces

Science.gov (United States)

deGroh, Henry C., III; Steinetz, Bruce M.

2009-01-01

While in space silicone based elastomer seals planned for use on NASA's Crew Exploration Vehicle (CEV) are exposed to threats from micrometeoroids and orbital debris (MMOD). An understanding of these threats is required to assess risks to the crew, the CEV orbiter, and missions. An Earth based campaign of hypervelocity impacts on small scale seal rings has been done to help estimate MMOD threats to the primary docking seal being developed for the Low Impact Docking System (LIDS). LIDS is being developed to enable the CEV to dock to the ISS (International Space Station) or to Altair (NASA's next lunar lander). The silicone seal on LIDS seals against aluminum alloy flanges on ISS or Altair. Since the integrity of a seal depends on both sealing surfaces, aluminum targets were also impacted. The variables considered in this study included projectile mass, density, speed, incidence angle, seal materials, and target surface treatments and coatings. Most of the impacts used a velocity near 8 km/s and spherical aluminum projectiles (density = 2.7 g/cubic cm), however, a few tests were done near 5.6 km/s. Tests were also performed using projectile densities of 7.7, 2.79, 2.5 or 1.14 g/cubic cm. Projectile incidence angles examined included 0 deg, 45 deg, and 60 deg from normal to the plane of the target. Elastomer compounds impacted include Parker's S0383-70 and Esterline's ELA-SA-401 in the as received condition, or after an atomic oxygen treatment. Bare, anodized and nickel coated aluminum targets were tested simulating the candidate mating seal surface materials. After impact, seals and aluminum plates were leak tested: damaged seals were tested against an undamaged aluminum plate; and undamaged seals were placed at various locations over craters in aluminum plates. It has been shown that silicone elastomer seals can withstand an impressive level of damage before leaking beyond allowable limits. In general on the tests performed to date, the diameter of the crater in

First result of deuterium retention in neutron-irradiated tungsten exposed to high flux plasma in TPE

International Nuclear Information System (INIS)

Shimada, Masashi; Hatano, Y.; Calderoni, P.; Oda, T.; Oya, Y.; Sokolov, M.; Zhang, K.; Cao, G.; Kolasinski, R.; Sharpe, J.P.

2011-01-01

With the Japan-US joint research project Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), an initial set of tungsten samples (99.99% purity, A.L.M.T. Co.) were irradiated by high flux neutrons at 323 K to 0.025 dpa in High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Subsequently, one of the neutron-irradiated tungsten samples was exposed to a high-flux deuterium plasma (ion flux: 5 x 10 21 m -2 s -1 , ion fluence: 4 x 10 25 m -2 ) in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory (INL). The deuterium retention in the neutron-irradiated tungsten was 40% higher in comparison to the unirradiated tungsten. The observed broad desorption spectrum from neutron-irradiated tungsten and associated TMAP modeling of the deuterium release suggest that trapping occurs in the bulk material at more than three different energy sites.

First result of deuterium retention in neutron-irradiated tungsten exposed to high flux plasma in TPE

Science.gov (United States)

Shimada, Masashi; Hatano, Y.; Calderoni, P.; Oda, T.; Oya, Y.; Sokolov, M.; Zhang, K.; Cao, G.; Kolasinski, R.; Sharpe, J. P.

2011-08-01

With the Japan-US joint research project Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), an initial set of tungsten samples (99.99% purity, A.L.M.T. Co.) were irradiated by high flux neutrons at 323 K to 0.025 dpa in High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Subsequently, one of the neutron-irradiated tungsten samples was exposed to a high-flux deuterium plasma (ion flux: 5 × 1021 m-2 s-1, ion fluence: 4 × 1025 m-2) in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory (INL). The deuterium retention in the neutron-irradiated tungsten was 40% higher in comparison to the unirradiated tungsten. The observed broad desorption spectrum from neutron-irradiated tungsten and associated TMAP modeling of the deuterium release suggest that trapping occurs in the bulk material at more than three different energy sites.

Micro-vibration response of a stochastically excited sandwich beam with a magnetorheological elastomer core and mass

International Nuclear Information System (INIS)

Ying, Z G; Ni, Y Q

2009-01-01

Magnetorheological (MR) elastomers are used to construct a smart sandwich beam for micro-vibration control. The micro-vibration response of a clamped–free sandwich beam with an MR elastomer core and a supplemental mass under stochastic support micro-motion excitation is studied. The dynamic behavior of MR elastomer as a smart viscoelastic material is described by a complex modulus which is controllable by external magnetic field. The sixth-order partial differential equation of motion of the sandwich beam is derived from the dynamic equilibrium, constitutive and geometric relations. A frequency-domain solution method for the stochastic micro-vibration response of the sandwich beam is developed by using the frequency-response function, power spectral density function and spatial eigensolution. The root-mean-square velocity response in terms of the one-third octave frequency band is calculated, and then the response reduction capacity through optimizing the complex modulus of the core is analyzed. Numerical results illustrate the influences of the MR elastomer core parameters on the root-mean-square velocity response and the high response reduction capacity of the sandwich beam. The developed analysis method is applicable to sandwich beams with arbitrary cores described by complex shear moduli under arbitrary stochastic excitations described by power spectral density functions

Evaluation of time-accelerated irradiation method of elastomer by modulus-ultimate elongation profile

International Nuclear Information System (INIS)

Ito, Masayuki; Oka, Toshitaka; Hama, Yosimasa

2009-01-01

'Generalized modulus-ultimate elongation profile' was induced from the relationship between the modulus and the ultimate elongation of an elastomer that was quantitatively added crosslinking and scission. This profile can be used to evaluate the time-accelerated irradiation methods of ethylene-propylene-diene elastomer. The irradiation under low dose rate (0.33 kGy/h) at room temperature was the reference condition. The short-time irradiation condition was 4.2 kGy/h in 0.5 MPa oxygen at room temperature and 5.0 kGy/h in air at 70 o C. The former tended to bring about the higher ratio of scission than the reference condition; the latter tended to bring about the higher ratio of crosslinking.

Thermoplastic film camera for holographic recording

International Nuclear Information System (INIS)

Liegeois, C.; Meyrueis, P.

1982-01-01

The design thermoplastic-film recording camera and its performance for holography of extended objects are reported. Special corona geometry and accurate control of development heat by constant current heating and high resolution measurement of the develop temperature make easy recording of reproducible, large aperture holograms possible. The experimental results give the transfer characteristics, the diffraction efficiency characteristics and the spatial frequency response. (orig.)

Shape-memory effect of nanocomposites based on liquid-crystalline elastomers

Science.gov (United States)

Marotta, A.; Lama, G. C.; Gentile, G.; Cerruti, P.; Carfagna, C.; Ambrogi, V.

2016-05-01

In this work, nanocomposites based on liquid crystalline (LC) elastomers were prepared and characterized in their shape memory properties. For the synthesis of materials, p-bis(2,3-epoxypropoxy)-α-methylstilbene (DOMS) was used as mesogenic epoxy monomer, sebacic acid (SA) as curing agent and multi-walled carbon nanotubes (MWCNT) and graphene oxide (GO) as fillers. First, an effective compatibilization methodology was set up to improve the interfacial adhesion between the matrix and the carbonaceous nanofillers, thus obtaining homogeneous distribution and dispersion of the nanofillers within the polymer phase. Then, the obtained nanocomposite films were characterized in their morphological and thermal properties. In particular, the effect of the addition of the nanofillers on liquid crystalline behavior, as well as on shape-memory properties of the realized materials was investigated. It was found that both fillers were able to enhance the thermomechanical response of the LC elastomers, making them good candidates as shape memory materials.

A mechanical characterisation on multiple timescales of electroconductive magnetorheological elastomers

Science.gov (United States)

Schümann, M.; Morich, J.; Kaufhold, T.; Böhm, V.; Zimmermann, K.; Odenbach, S.

2018-05-01

Magnetorheological elastomers are a type of smart hybrid material which combines elastic properties of a soft elastomer matrix with magnetic properties of magnetic micro particles. This leads to a material with magnetically controllable mechanical properties of which the magnetorheological effect is the best known. The addition of electroconductive particles to the polymer mix adds electrical properties to the material behaviour. The resulting electrical resistance of the sample can be manipulated by external magnetic fields and mechanical loads. This results in a distinct interplay of mechanical, electrical and magnetic effects with a highly complex time behaviour. In this paper a mechanical characterisation on multiple time scales was conducted to get an insight on the short and long-term electrical and mechanical behaviour of this novel material. The results show a complex resistivity behaviour on several timescales, sensitive to magnetic fields and strain velocity. The observed material exhibits fatigue and relaxation behaviour, whereas the magnetorheological effect appears not to interfere with the piezoresistive properties.

Towards holonomic electro-elastomer actuators with six degrees of freedom

International Nuclear Information System (INIS)

Conn, A T; Rossiter, J

2012-01-01

Functionally efficient six degree of freedom (DOF) actuators have not yet been developed in a scale-invariant and inherently compliant unified form. This has primarily been due to the use of conventional serial or parallel kinematical configurations and electromagnetic motors, pneumatics and hydraulics. Contrary to traditional technologies, utilizing electro-active elastomers enables multi-DOF actuation and holonomic operation with minimal structural complexity. Conical dielectric elastomer actuators (DEAs) are compact multi-DOF actuator–sensors that are scalable and can be entirely polymeric, making them suitable for a variety of applications including minimally invasive medical devices. In this paper, cone DEAs are developed towards integrated 6-DOF actuation with muscle-like performance from a single structure. This is achieved by demonstrating the feasibility of holonomic 6-DOF actuation and through experimental characterization of a 5-DOF prototype. The 5-DOF prototype (50 mm length, 60 mm diameter) produced rotational actuation outputs of ±21.7° and ±9.42 mN m and linear actuation outputs of ±4.45 mm (±9.1%) and ±0.55 N. Finally, combined multi-DOF actuation is demonstrated as part of development towards scalable holonomic electro-active elastomer actuators. (paper)

Towards holonomic electro-elastomer actuators with six degrees of freedom

Science.gov (United States)

Conn, A. T.; Rossiter, J.

2012-03-01

Functionally efficient six degree of freedom (DOF) actuators have not yet been developed in a scale-invariant and inherently compliant unified form. This has primarily been due to the use of conventional serial or parallel kinematical configurations and electromagnetic motors, pneumatics and hydraulics. Contrary to traditional technologies, utilizing electro-active elastomers enables multi-DOF actuation and holonomic operation with minimal structural complexity. Conical dielectric elastomer actuators (DEAs) are compact multi-DOF actuator-sensors that are scalable and can be entirely polymeric, making them suitable for a variety of applications including minimally invasive medical devices. In this paper, cone DEAs are developed towards integrated 6-DOF actuation with muscle-like performance from a single structure. This is achieved by demonstrating the feasibility of holonomic 6-DOF actuation and through experimental characterization of a 5-DOF prototype. The 5-DOF prototype (50 mm length, 60 mm diameter) produced rotational actuation outputs of ±21.7° and ±9.42 mN m and linear actuation outputs of ±4.45 mm (±9.1%) and ±0.55 N. Finally, combined multi-DOF actuation is demonstrated as part of development towards scalable holonomic electro-active elastomer actuators.

Synthesis and Effect of Hierarchically Structured Ag-ZnO Hybrid on the Surface Antibacterial Activity of a Propylene-Based Elastomer Blends

Directory of Open Access Journals (Sweden)

Pavel Bazant

2018-03-01

Full Text Available In this study, a hybrid Ag-ZnO nanostructured micro-filler was synthesized by the drop technique for used in plastic and medical industry. Furthermore, new antibacterial polymer nanocomposites comprising particles of Ag-ZnO up to 5 wt % and a blend of a thermoplastic polyolefin elastomer (TPO with polypropylene were prepared using twin screw micro-compounder. The morphology and crystalline-phase structure of the hybrid Ag-ZnO nanostructured microparticles obtained was characterized by scanning electron microscopy and powder X-ray diffractometry. The specific surface area of this filler was investigated by means of nitrogen sorption via the Brunauer-Emmet-Teller method. A scanning electron microscope was used to conduct a morphological study of the polymer nanocomposites. Mechanical and electrical testing showed no adverse effects on the function of the polymer nanocomposites either due to the filler utilized or the given processing conditions, in comparison with the neat polymer matrix. The surface antibacterial activity of the compounded polymer nanocomposites was assessed against Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538P, according to ISO 22196:2007 (E. All the materials at virtually every filler-loading level were seen to be efficient against both species of bacteria.

Can rubber help against the greenhouse effect?

NARCIS (Netherlands)

Blume, Anke

2015-01-01

Car traffic has a significant share in worldwide greenhouse gas emissions. ­Despite many improvements in the past there is still a big potential for further reductions of the CO2 emissions. Many parts of a car can be replaced by thermoplastics or elastomers in order to reduce weight. In addition,

Effects of ionizing radiations

International Nuclear Information System (INIS)

Gaussens, G.

1984-08-01

After recalling radiation-matter interaction, influence on radiation effects of chemical composition, structure, irradiation atmosphere, dose rate, temperature of organic materials and evolution of electrical, mechanical and physical properties are reviewed. Then behaviour under irradiation of main organic materials: elastomers, thermoplastics, thermosetting plastics, oils and paints are examined. 68 refs [fr

The static actuation of dielectric elastomer actuators: how does pre-stretch improve actuation?

International Nuclear Information System (INIS)

Kofod, Guggi

2008-01-01

It has previously been shown that providing dielectric elastomer actuators with a level of pre-stretch can improve properties such as breakdown strength, actuation strain and efficiency. The actuation in such actuators depends on an interplay between the highly nonlinear hyperelastic stress-strain behaviour with the electrostatic Maxwell's stress; however, the direct effects of pre-stretch on the electromechanical coupling have still not been investigated in detail. We compare several experimental results found in the literature on the hyperelastic parameters of the Ogden model for the commonly used material VHB 4910, and introduce a more detailed and thus more accurate fit to a previous uniaxial stress-strain experiment. Electrostatic actuation models for a pure shear cuboid dielectric elastomer actuator with pre-stretch are introduced, for both intensive and extensive variables. For both intensive and extensive variables the constant strain (blocked stress or force) as well as the actuation strain is presented. It is shown how in the particular case of isotropic amorphous elastomers the pre-stretch does not affect the electromechanical coupling directly, and that the enhancement in actuation strain due to pre-stretch occurs through the alteration of the geometrical dimensions of the actuator. Also, the presence of the optimum load is explained as being due to the plateau region in the force-stretch curve, and it is shown that pre-stretch is not able to affect its position. Finally, it is shown how the simplified Ogden fit leads to entirely different conclusions for actuation strain in terms of extensive variables as does the detailed fit, emphasizing the importance of employing accurate hyperelastic models for the stress-stretch behaviour of the elastomer.

Mechanical behaviour of textile-reinforced thermoplastics with integrated sensor network components

International Nuclear Information System (INIS)

Hufenbach, W.; Adam, F.; Fischer, W.-J.; Kunadt, A.; Weck, D.

2011-01-01

Highlights: → Consideration of two types of integrated bus systems for textile-reinforced thermoplastics with embedded sensor networks. → Specimens with bus systems made of flexible printed circuit boards show good mechanical performance compared to the reference. → Inhomogeneous interface and reduced stiffnesses and strengths for specimens with bus systems basing on single copper wires. -- Abstract: The embedding of sensor networks into textile-reinforced thermoplastics enables the design of function-integrative lightweight components suitable for high volume production. In order to investigate the mechanical behaviour of such functionalised composites, two types of bus systems are selected as exemplary components of sensor networks. These elements are embedded into glass fibre-reinforced polypropylene (GF/PP) during the layup process of unconsolidated weft-knitted GF/PP-preforms. Two fibre orientations are considered and orthotropic composite plates are manufactured by hot pressing technology. Micrograph investigations and computer tomography analyses show different interface qualities between the thermoplastic composite and the two types of bus systems. Mechanical tests under tensile and flexural loading indicate a significant influence of the embedded bus system elements on the structural stiffness and strength.

Graphite and PMMA as pore formers for thermoplastic extrusion of porous 3Y-TZP oxygen transport membrane supports

DEFF Research Database (Denmark)

Bjørnetun Haugen, Astri; Gurauskis, Jonas; Kaiser, Andreas

2016-01-01

A gas permeable porous support is a crucial part of an asymmetric oxygen transport membrane (OTM). Here, we develop feedstocks for thermoplastic extrusion of tubular, porous 3Y-TZP (partially stabilized zirconia polycrystals, (Y2O3)0.03(ZrO2)0.97)) ceramics, using graphite and/or polymethyl....... This demonstrates the suitability of thermoplastic extrusion for fabrication of porous 3Y-TZP OTM supports, or for other technologies requiring porous ceramics....

First result of deuterium retention in neutron-irradiated tungsten exposed to high flux plasma in TPE

Energy Technology Data Exchange (ETDEWEB)

Shimada, Masashi, E-mail: Masashi.Shimada@inl.gov [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Hatano, Y. [Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan); Calderoni, P. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Oda, T. [Department of Nuclear Engineering and Management, The University of Tokyo, Tokyo 113-8656 (Japan); Oya, Y. [Radioscience Research Laboratory, Faculty of Science, Shizuoka University, Shizuoka 422-8529 (Japan); Sokolov, M. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zhang, K. [Hydrogen Isotope Research Center, University of Toyama, Toyama 930-8555 (Japan); Cao, G. [Department of Engineering Physics, University of Wisconsin-Madison, Madison, WI 53706 (United States); Kolasinski, R. [Hydrogen and Metallurgical Science Department, Sandia National Laboratories, Livermore, CA 94551 (United States); Sharpe, J.P. [Fusion Safety Program, Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

2011-08-01

With the Japan-US joint research project Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), an initial set of tungsten samples (99.99% purity, A.L.M.T. Co.) were irradiated by high flux neutrons at 323 K to 0.025 dpa in High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Subsequently, one of the neutron-irradiated tungsten samples was exposed to a high-flux deuterium plasma (ion flux: 5 x 10{sup 21} m{sup -2} s{sup -1}, ion fluence: 4 x 10{sup 25} m{sup -2}) in the Tritium Plasma Experiment (TPE) at Idaho National Laboratory (INL). The deuterium retention in the neutron-irradiated tungsten was 40% higher in comparison to the unirradiated tungsten. The observed broad desorption spectrum from neutron-irradiated tungsten and associated TMAP modeling of the deuterium release suggest that trapping occurs in the bulk material at more than three different energy sites.

Diamond turning of thermoplastic polymers

Energy Technology Data Exchange (ETDEWEB)

Smith, E.; Scattergood, R.O.

1988-12-01

Single point diamond turning studies were made using a series of thermoplastic polymers with different glass transition temperatures. Variations in surface morphology and surface roughness were observed as a function of cutting speed. Lower glass transition temperatures facilitate smoother surface cuts and better surface finish. This can be attributed to the frictional heating that occurs during machining. Because of the very low glass transition temperatures in polymeric compared to inorganic glasses, the precision machining response can be very speed sensitive.

Mimicking biological stress-strain behaviour with synthetic elastomers

Science.gov (United States)

Vatankhah-Varnosfaderani, Mohammad; Daniel, William F. M.; Everhart, Matthew H.; Pandya, Ashish A.; Liang, Heyi; Matyjaszewski, Krzysztof; Dobrynin, Andrey V.; Sheiko, Sergei S.

2017-09-01

Despite the versatility of synthetic chemistry, certain combinations of mechanical softness, strength, and toughness can be difficult to achieve in a single material. These combinations are, however, commonplace in biological tissues, and are therefore needed for applications such as medical implants, tissue engineering, soft robotics, and wearable electronics. Present materials synthesis strategies are predominantly Edisonian, involving the empirical mixing of assorted monomers, crosslinking schemes, and occluded swelling agents, but this approach yields limited property control. Here we present a general strategy for mimicking the mechanical behaviour of biological materials by precisely encoding their stress-strain curves in solvent-free brush- and comb-like polymer networks (elastomers). The code consists of three independent architectural parameters—network strand length, side-chain length and grafting density. Using prototypical poly(dimethylsiloxane) elastomers, we illustrate how this parametric triplet enables the replication of the strain-stiffening characteristics of jellyfish, lung, and arterial tissues.

Enhanced printability of thermoplastic polyurethane substrates by silica particles surface interactions

Energy Technology Data Exchange (ETDEWEB)

Cruz, S., E-mail: s.cruz@dep.uminho.pt [IPC/I3N – Institute of Polymers and Composites/Inst. of Nanostructures, Nanomodelling and Nanofabrication, Department Polymer Engineering, University of Minho, 4804-533 Guimarães (Portugal); Rocha, L.A. [CMEMS, University of Minho, 4804-533 Guimarães (Portugal); Viana, J.C. [IPC/I3N – Institute of Polymers and Composites/Inst. of Nanostructures, Nanomodelling and Nanofabrication, Department Polymer Engineering, University of Minho, 4804-533 Guimarães (Portugal)

2016-01-01

Graphical abstract: - Highlights: • A new method development for surface treatment of thermoplastic polyurethane (TPU) substrates. • The proposed method increases TPU surface energy (by 45%) and consequently the TPU wettability. • Great increase of the TPU surface roughness (by 621%). • Inkjet printed conductive ink was applied to the surface treated TPU substrate and significant improvements on the printability were obtained. - Abstract: A new method developed for the surface treatment of thermoplastic polymer substrates that increases their surface energies is introduced in this paper. The method is environmental friendly and low cost. In the proposed surface treatment method, nanoparticles are spread over the thermoplastic polyurethane (TPU) flexible substrate surface and then thermally fixed. This latter step allows the nanoparticles sinking-in on the polymer surface, resulting in a higher polymer–particle interaction at their interfacial region. The addition of nanoparticles onto the polymer surface increases surface roughness. The extent of the nanoparticles dispersion and sink-in in the substrate was evaluated through microscopy analysis (SEM). The roughness of the surface treated polymeric substrate was evaluated by AFM analysis. Substrate critical surface tension (ST) was measured by contact angle. In general, a homogeneous roughness form is achieved to a certain level. Great increase of the TPU surface roughness (by 621%) was induced by the propose method. The proposed surface treatment method increased significantly the substrate ST (by 45%) and consequently the TPU wettability. This novel surface treatment of thermoplastic polymers was applied to the inkjet printing of TPU substrates with conductive inks, and significant improvements on the printability were obtained.

Synthesis of novel lidocaine-releasing poly(diol-co-citrate) elastomers by using deep eutectic solvents.

Science.gov (United States)

Serrano, M Concepción; Gutiérrez, María C; Jiménez, Ricardo; Ferrer, M Luisa; del Monte, Francisco

2012-01-14

Poly(octanediol-co-citrate) elastomers containing high loading of lidocaine were synthesized at temperatures below 100 °C by means of using deep eutectic mixtures of 1,8-octanediol and lidocaine. The preservation of lidocaine integrity resulted in high-capacity drug-eluting elastomers. This journal is © The Royal Society of Chemistry 2012

Materials and process limitations for thermoplastic composite materials for wind turbine blades - preform of prepregs and commingled yarns

Energy Technology Data Exchange (ETDEWEB)

Prabhakaran, R.T.D.

2011-07-01

Wind turbine blades are produced based on the current thermoset resin technology, but thermoplastics can offer better potential to become the future blade materials. One of the most important goals when designing larger blade systems is to keep the blade weight under control. Thermoplastic materials offer weight saving similar to thermosets, apart from many other benefits like design flexibility, durability, cost, weight saving, and performance advantageous to the wind industry. In the current research study a detailed discussion on material and process limitations such as thermoplastic prepreg tapes and commingled yams are presented in terms of their properties and available forms in the current markets. A critical review of thermoplastics discussed in the context of turbine blades applications. (Author)

The effect of titanium surface treatment on the interfacial strength of titanium – Thermoplastic composite joints

NARCIS (Netherlands)

Su, Yibo; de Rooij, Matthijn; Grouve, Wouter; Akkerman, Remko

2017-01-01

Co-consolidated titanium – carbon fibre reinforced thermoplastic composite hybrid joints show potential for application in aerospace structures. The strength of the interface between the titanium and the thermoplastic composite is crucial for the strength of the entire hybrid joint. Application of a

Method and apparatus for extruding thermoplastic material

International Nuclear Information System (INIS)

McKelvey, J.M.

1985-01-01

A gear pump assisted screw conveyor extrusion system utilizing a cartridge heating device disposed axially within the screw and having the drives for the gear pump and the screw correlated in speed to create relatively little pressure in the thermoplastic material being extruded such that relatively little mechanical working thereof occurs. The thermoplastic material is melted in the screw conveyor primarily by heat transfer from the cartridge heater and the gear pump is utilized for conveying the melted material under pressure to a subsequent work station. A relatively deep material-conveying spiral channel is provided in the screw for maximized extrusion output per revolution of the screw and minimized mechanical energy generation by the screw. A motionless mixer may be employed intermediate the screw and the work station to homogenize the melted material for reducing temperature gradients therein. The system advantageously is capable of extruding material at a substantially greater rate and a lower material temperature and with substantially increased power economy than conventional systems utilizing a high pressure, externally heated screw conveyor portion

Resistance Welding of Thermoplastic Composites : Process and Performance

NARCIS (Netherlands)

Shi, H.

2014-01-01

Compared to thermoset composites, thermoplastic composites are drawing more and more attention by aircraft industries not only due to their excellent material properties but also due to their potentials to reduce cycle time and structure cost by using low-cost manufacturing technologies such as

Clinical application of removable partial dentures using thermoplastic resin. Part II: Material properties and clinical features of non-metal clasp dentures.

Science.gov (United States)

Fueki, Kenji; Ohkubo, Chikahiro; Yatabe, Masaru; Arakawa, Ichiro; Arita, Masahiro; Ino, Satoshi; Kanamori, Toshikazu; Kawai, Yasuhiko; Kawara, Misao; Komiyama, Osamu; Suzuki, Tetsuya; Nagata, Kazuhiro; Hosoki, Maki; Masumi, Shin-ichi; Yamauchi, Mutsuo; Aita, Hideki; Ono, Takahiro; Kondo, Hisatomo; Tamaki, Katsushi; Matsuka, Yoshizo; Tsukasaki, Hiroaki; Fujisawa, Masanori; Baba, Kazuyoshi; Koyano, Kiyoshi; Yatani, Hirofumi

2014-04-01

This position paper reviews physical and mechanical properties of thermoplastic resin used for non-metal clasp dentures, and describes feature of each thermoplastic resin in clinical application of non-metal clasp dentures and complications based on clinical experience of expert panels. Since products of thermoplastic resin have great variability in physical and mechanical properties, clinicians should utilize them with careful consideration of the specific properties of each product. In general, thermoplastic resin has lower color-stability and higher risk for fracture than polymethyl methacrylate. Additionally, the surface of thermoplastic resin becomes roughened more easily than polymethyl methacrylate. Studies related to material properties of thermoplastic resin, treatment efficacy and follow-up are insufficient to provide definitive conclusions at this time. Therefore, this position paper should be revised based on future studies and a clinical guideline should be provided. Copyright © 2014 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

A novel variable stiffness mechanism for dielectric elastomer actuators

Science.gov (United States)

Li, Wen-Bo; Zhang, Wen-Ming; Zou, Hong-Xiang; Peng, Zhi-Ke; Meng, Guang

2017-08-01

In this paper, a novel variable stiffness mechanism is proposed for the design of a variable stiffness dielectric elastomer actuator (VSDEA) which combines a flexible strip with a DEA in a dielectric elastomer minimum energy structure. The DEA induces an analog tuning of the transverse curvature of the strip, thus conveniently providing a voltage-controllable flexural rigidity. The VSDEA tends to be a fully flexible and compact structure with the advantages of simplicity and fast response. Both experimental and theoretical investigations are carried out to reveal the variable stiffness performances of the VSDEA. The effect of the clamped location on the bending stiffness of the VSDEA is analyzed, and then effects of the lengths, the loading points and the applied voltages on the bending stiffness are experimentally investigated. An analytical model is developed to verify the availability of this variable stiffness mechanism, and the theoretical results demonstrate that the bending stiffness of the VSDEA decreases as the applied voltage increases, which agree well with the experimental data. Moreover, the experimental results show that the maximum change of the relative stiffness can reach about 88.80%. It can be useful for the design and optimization of active variable stiffness structures and DEAs for soft robots, vibration control, and morphing applications.

Crash simulation of hybrid structures considering the stress and strain rate dependent material behavior of thermoplastic materials

Science.gov (United States)

Hopmann, Ch.; Schöngart, M.; Weber, M.; Klein, J.

2015-05-01

Thermoplastic materials are more and more used as a light weight replacement for metal, especially in the automotive industry. Since these materials do not provide the mechanical properties, which are required to manufacture supporting elements like an auto body or a cross bearer, plastics are combined with metals in so called hybrid structures. Normally, the plastics components are joined to the metal structures using different technologies like welding or screwing. Very often, the hybrid structures are made of flat metal parts, which are stiffened by a reinforcement structure made of thermoplastic materials. The loads on these structures are very often impulsive, for example in the crash situation of an automobile. Due to the large stiffness variation of metal and thermoplastic materials, complex states of stress and very high local strain rates occur in the contact zone under impact conditions. Since the mechanical behavior of thermoplastic materials is highly dependent on these types of load, the crash failure of metal plastic hybrid parts is very complex. The problem is that the normally used strain rate dependent elastic/plastic material models are not capable to simulate the mechanical behavior of thermoplastic materials depended on the state of stress. As part of a research project, a method to simulate the mechanical behavior of hybrid structures under impact conditions is developed at the IKV. For this purpose, a specimen for the measurement of mechanical properties dependet on the state of stress and a method for the strain rate depended characterization of thermoplastic materials were developed. In the second step impact testing is performed. A hybrid structure made from a metal sheet and a reinforcement structure of a Polybutylenterephthalat Polycarbonate blend is tested under impact conditions. The measured stress and strain rate depended material data are used to simulate the mechanical behavior of the hybrid structure under highly dynamic load with

Soft Functional Silicone Elastomers with High Dielectric Permittivty: Simple Additives vs. Cross-Linked Synthesized Copolymers

DEFF Research Database (Denmark)

Madsen, Frederikke Bahrt; Yu, Liyun; Skov, Anne Ladegaard

Though dielectric elastomers (DEs) have many favorable properties, the issue of high driving voltages limits the commercial viability of the technology. Improved actuation at lower voltages can be obtained by decreasing the Young’s modulus and/or decreasing the dielectric permittivity of the elas......Though dielectric elastomers (DEs) have many favorable properties, the issue of high driving voltages limits the commercial viability of the technology. Improved actuation at lower voltages can be obtained by decreasing the Young’s modulus and/or decreasing the dielectric permittivity...... of the elastomer. A decrease in Young’s modulus, however, is often accompanied by the loss of mechanical stability and thereby the lifetime of the DE whereas addition of high permittivity fillers such as metal oxides often increases Young’s modulus such that improved actuation is not accomplished. New soft...... silicone elastomers with high dielectric permittivity were prepared through the use of chloropropyl-functional silicones. One method was through the synthesis of modular cross-linkable chloropropyl-functional copolymers that allow for a high degree of chemical freedom such that a tuneable silicone...

Mechanical properties of carbon fibre reinforced thermoplastics for cryogenic applications

International Nuclear Information System (INIS)

Ahlborn, K.

1989-01-01

The high specific strength, the high specific stiffness and the excellent fatigue behaviour favours carbon fibre reinforced plastics (CFRP) as a supplement to metals for low temperature applications. The weakest link in the composite is the polymeric matrix, which is preloaded by thermal tensile strains and becomes brittle at low temperatures. Tough thermoplastic polymers show a higher cryogenic fracture strain than commonly used epoxy-matrix systems. Two carbon fibre reinforced tough thermoplastics (PEEK, PC) were tested at 293 K, 77 K and 5 K by tensile, bending and fatigue loading. It has been found, that the toughness of the matrices generally improves the static strength at low temperatures. In bidirectionally reinforced thermoplastics, transversal cracks appear in the matrix or in the boundary layer at composite strains below 0,2%, originated by the thermal preloading. The formation and development of the cracks depend on the fibre-matrix-bond and on the thickness of the composite layers. Fibre-misalignment results in a poor tension-tension fatigue endurance limit of less than 50% of the static strength. Further developments in the manufacturing process are necessary to improve the homogeneity of the composite structure in order to increase the long term fatigue behaviour. (orig.) [de

Pengerasan Pada Bahan Cetak Elastomer Polyether

OpenAIRE

Azree Zayani M.S.

2011-01-01

Bahan cetak polyether merupakan bahan elastomer yang digunakan di kedokteran gigi. Terdapat empat kelas menurut konsistensi dan viskositas yaitu (1) light body (2)medium atau regular body (3) heavy body: dan (4) Putty. Komposisi bahan cetak polyether terdiri dari pasta base dan pasta katalis. Pasta base mengandung polimer polyether, kolloidal silika sebagai bahan pengisi, dan plastisizer yaitu glikoeter atau phthalate. Pasta katalis mengandung alkil aromatik sulfonat ditambah dengan baha...

Modelling and characterization of inflated dielectric elastomer actuators with tubular configuration

International Nuclear Information System (INIS)

Zhang, Chi; Chen, Hualing; Liu, Lei; Li, Dichen

2015-01-01

A dielectric elastomer undergoes large and fast deformation subject to external electric stimuli, making it a promising artificial muscle for various kinds of actuators, sensors and energy generators. This paper presents an actuator fabricated by (1) rolling a dielectric elastomer membrane, (2) pre-stretching the membrane along the radial direction and fixing the edges with rigid cylindrical plastic ends, and (3) applying a force to the end along the longitudinal direction and pumping air into the tube for inflation. Subject to a voltage, the structure works as an actuator with a large linear stroke. Governing equations of this actuator are established and simulation results are found to agree well with experimental results. We examine four modes of failure, namely loss of tension, electrical breakdown, snap-through instability and tensile rupture, with a variation in applied pressure. The actuating voltage is greatly reduced by applying pressure, providing the possibility of low-voltage driving. By regulating the applied pressure, large actuation strain and displacement are obtained simultaneously and the distributions of stretch, true stress and the true electric field become more homogeneous. (paper)

Integrated Force and Distance Sensing using Elastomer-Embedded Commodity Proximity Sensors.

Energy Technology Data Exchange (ETDEWEB)

Patel, Radhen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cox, Rebecca E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Correll, Nikolaus [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-02-01

We describe a combined proximity, contact and force (PCF) sensor based on a commodity infrared distance sensor embedded in a transparent elastomer with applications in robotic manipulation. Prior to contact, the sensor works as a distance sensor (0{6 cm), whereas after contact the material doubles as a spring, with force proportional to the compression of the elastomer (0{5 N). We describe its principle of operation and design parameters, including polymer thickness, mixing ratio, and emitter current, and show that the sensor response has an in ection point at contact that is independent of an object's surface properties, making it a robust detector for contact events. We then demonstrate how arrays of sensors, custom made for a standard Baxter gripper as well as embedded in the nger of the Kinova hand, can be used to (1) improve gripper alignment during grasping, (2) determine contact points with objects, (3) obtain simple 3D models using both proximity and touch, and (4) register point clouds from touch and RGB-D data.

Packaging related properties of commercially available biopolymers – An overview of the status quo

Directory of Open Access Journals (Sweden)

V. Jost

2018-05-01

Full Text Available Several commercially available thermoplastic biopolymers were processed in a continuous extrusion line. The molecular weight, crystallinity, and mechanical and permeation properties of the cast films were determined in order to evaluate the status quo of biopolymers currently commercially available. The biopolymers that were evaluated were polylactic acid (PLA, several polyhydroxyalkanoates (PHAs (Poly(3-hydroxybutyrate (PHB, poly(3-hydroxybutyrate-co-4-hydroxybutyrate (PHBHB, poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV, thermoplastic starch (TPS, polybutylene adipate terephthalate (PBAT, polybutylene succinate (PBS, polycaprolactone (PCL and biobased polyethylene (BioPE. Due to its potential for biobased production, thermoplastic polyurethane elastomer (TPU was also analysed. Mechanical analysis showed the PLA and PHA films had high strength and extremely low elongation at break. These were also the materials with the highest molecular weights. Films made of TPU, PCL, TPS, PBAT and BioPE had a significantly lower Young’s modulus and significantly higher elongation at break; these films had comparatively low molecular weights. Permeation measurements showed that PHA films, and particularly PHBV, had the lowest oxygen and water vapour permeability of the biopolymers that were analysed. The biopolymers BioPE, TPS, PCL, TPU and PBAT were highly permeable to oxygen, and had comparatively low molecular weight. The biopolymers TPU, PBS, PBAT, PCL and TPS were highly permeable to water vapour.

Novel polycarbonate-based polyurethane elastomers: composition–property relationship

Czech Academy of Sciences Publication Activity Database

Špírková, Milena; Pavličevic, J.; Strachota, Adam; Poreba, Rafal; Bera, O.; Kaprálková, Ludmila; Baldrian, Josef; Šlouf, Miroslav; Lazić, N.; Budinski-Simendic, J.

2011-01-01

Roč. 47, č. 5 (2011), s. 959-972 ISSN 0014-3057 R&D Projects: GA ČR GAP108/10/0195 Institutional research plan: CEZ:AV0Z40500505 Keywords : polyurethane elastomer * polycarbonate diol * montmorillonite Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.739, year: 2011

Improving bondability to RTV silicone elastomer using rf-activated gas

International Nuclear Information System (INIS)

Bellah, J.L.

1979-05-01

The effects of an rf-activated gas (plasma) on the bondability to RTV silicone elastomer were studied. Processing guidelines were developed, and a method was sought to satisfactorily bond RTV to the walls of a machined aluminum casting and to provide a surface on the RTV which would best accept bonding to an epoxy encapsulant. Processing parameters, such as gas type and flow rate, reaction chamber pressure, and rf power level, were developed

Evolution of umbilicals in Brazil: optimizing deepwater umbilical applications with thermoplastic hoses and steel tubes

Energy Technology Data Exchange (ETDEWEB)

Guerra Neto, Mauro Del [DuPont do Brasil S.A., Barueri, SP (Brazil)

2008-07-01

Subsea umbilicals in the past 25 years have evolved in parallel with other subsea oil and gas technologies, as the search for hydrocarbons needed to drive the global economy has led offshore exploration and development companies to seek reserves ever-farther from shore in water thousands of meters deep. Relegated to little more than afterthought status before the push into deep water, modern umbilicals have now become crucial components linking deep water producers to their subsea wells, controlling subsea production systems through hydraulic and electrical power and injecting production chemicals for corrosion-, scale-, and hydrate-inhibition at subsea well heads. Particularly in subsea developments involving several deep water wells, umbilicals today are integral to both the production-system design and the chosen operating strategy. Failure of an umbilical linking a subsea well head in deep water to a host production facility can inflict severe economic consequences upon an operator by impairing production operations or halting production altogether. The additional cost of repairing or replacing a failed umbilical can run into the millions of dollars. As offshore oil and gas production has moved into ever-deeper water, umbilical manufacturers have begun introducing new stronger materials to handle the inherently higher pressures and temperatures. Today, two types of construction are used for fluid conduits in umbilical systems deployed in deep water: thermoplastic hoses and steel tubes. Steel tubes are generally more expensive than thermoplastic hoses, relatively stiff and considered to have high tensile strength, while thermoplastic hoses are extremely flexible and exhibit lower tensile strength. This lower tensile strength of the hoses may be compensated by including steel wire armoring in the umbilical. This also provides the added benefits of additional mechanical protection compared with the equivalent unarmored steel-tubes umbilicals. When either

Effects of Styrene-Acrylic Sizing on the Mechanical Properties of Carbon Fiber Thermoplastic Towpregs and Their Composites.

Science.gov (United States)

Bowman, Sean; Jiang, Qiuran; Memon, Hafeezullah; Qiu, Yiping; Liu, Wanshuang; Wei, Yi

2018-03-01

Thermoplastic towpregs are convenient and scalable raw materials for the fabrication of continuous fiber-reinforced thermoplastic matrix composites. In this paper, the potential to employ epoxy and styrene-acrylic sizing agents was evaluated for the making of carbon fiber thermoplastic towpregs via a powder-coating method. The protective effects and thermal stability of these sizing agents were investigated by single fiber tensile test and differential scanning calorimetry (DSC) measurement. The results indicate that the epoxy sizing agent provides better protection to carbon fibers, but it cannot be used for thermoplastic towpreg processing due to its poor chemical stability at high temperature. The bending rigidity of the tows and towpregs with two styrene-acrylic sizing agents was measured by cantilever and Kawabata methods. The styrene-acrylic sized towpregs show low torque values, and are suitable for further processing, such as weaving, preforming, and winding. Finally, composite panels were fabricated directly from the towpregs by hot compression molding. Both of the composite panels show superior flexural strength (>400 MPa), flexural modulus (>63 GPa), and interlaminar shear strength (>27 MPa), indicating the applicability of these two styrene-acrylic sizing agents for carbon fiber thermoplastic towpregs.

Effects of Styrene-Acrylic Sizing on the Mechanical Properties of Carbon Fiber Thermoplastic Towpregs and Their Composites

Directory of Open Access Journals (Sweden)

Sean Bowman

2018-03-01

Full Text Available Thermoplastic towpregs are convenient and scalable raw materials for the fabrication of continuous fiber-reinforced thermoplastic matrix composites. In this paper, the potential to employ epoxy and styrene-acrylic sizing agents was evaluated for the making of carbon fiber thermoplastic towpregs via a powder-coating method. The protective effects and thermal stability of these sizing agents were investigated by single fiber tensile test and differential scanning calorimetry (DSC measurement. The results indicate that the epoxy sizing agent provides better protection to carbon fibers, but it cannot be used for thermoplastic towpreg processing due to its poor chemical stability at high temperature. The bending rigidity of the tows and towpregs with two styrene-acrylic sizing agents was measured by cantilever and Kawabata methods. The styrene-acrylic sized towpregs show low torque values, and are suitable for further processing, such as weaving, preforming, and winding. Finally, composite panels were fabricated directly from the towpregs by hot compression molding. Both of the composite panels show superior flexural strength (>400 MPa, flexural modulus (>63 GPa, and interlaminar shear strength (>27 MPa, indicating the applicability of these two styrene-acrylic sizing agents for carbon fiber thermoplastic towpregs.

Nanoimprint technology nanotransfer for thermoplastic and photocurable polymers

CERN Document Server

Taniguchi, Jun; Mizuno, Jun; Saito, Takushi

2013-01-01

Nanoscale pattern transfer technology using molds is a rapidly advancing area and one that has seen much recent attention due to its potential for use in nanotechnology industries and applications. However, because of these rapid advances, it can be difficult to keep up with the technological trends and the latest cutting-edge methods. In order to fully understand these pioneering technologies, a comprehensive understanding of the basic science and an overview of the techniques are required. Nanoimprint Technology: Nanotransfer for Thermoplastic and Photocurable Polymers covers

On the decrease of ultimate elongation of gum elastomer by irradiation

International Nuclear Information System (INIS)

Ito, Masayuki

1986-01-01

The reason why the ultimate elongation of gum elastomer decreases by irradiation was studied. The sample used is tetrafluoroethylenepropylene copolymer vulcanized which is a heat resistant elastomer. The sample was irradiated by a electron beam at room temperature. Cross-linking predominate in the operation. (Case 1) Scission predominant condition (Case 2) was given by irradiation of Co-60 γ ray at 100 deg C. Alternative irradiation of γ ray and electron beam under above condition can keep the original cross-linking density by the appropriate choice of each of the doses. (Case 3) The three cases mentioned above involve all of the cases of radiation induced aging of elastomers. Therefor, the following explanation for three cases shows the reason why the ultimate elongation of gum elastomer decreases by irradiation. Case 1. Cross-linking predominant condition. Ultimate elongation is proportional to -0.5 power of the dose. This fact can be explicable by the model of Buche, i.e. the breaking of a short chain causes another to break and that so on throughout the whole sample. Case 2. Chain scission predominant condition. Ultimate elongation increases by irradiation for a certain dose. This fact can understand by the model of Buche. But from a certain dose ultimate elongation does not increase. In the period the structure of the sample turned to be the same structure as the low molecular weight amorphose polymer vulcanized. Case 3. Rate of cross-linking and scission is the same. The average chain length does not chainge in the condition. But the distribution of chain length became wider and wider by irradiation. The increase of short chain result the decrease in ultimate elongation. (author)

Characterising the thermoforming behaviour of glass fibre textile reinforced thermoplastic composite materials

Science.gov (United States)

Kuhtz, M.; Maron, B.; Hornig, A.; Müller, M.; Langkamp, A.; Gude, M.

2018-05-01

Textile reinforced thermoplastic composites are predestined for highly automated medium- and high-volume production processes. The presented work focusses on experimental studies of different types of glass fibre reinforced polypropylene (GF-PP) semi-finished thermoplastic textiles to characterise the forming behaviour. The main deformation modes fabric shear, tension, thought-thickness compression and bending are investigated with special emphasis on the impact of the textile structure, the deformation temperature and rate dependency. The understanding of the fundamental forming behaviour is required to allow FEM based assessment and improvement of thermoforming process chains.

Impact of thermoplastic mask on dosimetry of different radiotherapeutic beams

International Nuclear Information System (INIS)

Chen Lixin; Zhang Li; Qian Jianyang; Huang Xiaoyan; Lu Jie; Huang Shaomin

2003-01-01

Objective: To determine the influence of auxiliary thermoplastic mask on dose distribution of photon or electron beams. Methods: Using the PTW Marcus 23343 type fixed-separation parallel-plate ionization chamber in a special phantom(PMMA), the change of photon dose buildup region was measured with rectification of Bruce empirical formula. Using 3-D water phantom, the central axis percentage depth doses (PDD) of electron beams were measured with verification of the parallel-plate ionization chamber at several given depths. Results: When 8 MV X-ray was delivered through the added facial mask, the buildup region doses were increased obviously with a 25% relative increment beneath near the surface. When 8, 12, 15 MeV electron beams and mask were used, all PDD curves moved to the surface. Conclusions: The impact of thermoplastic mask on the dose increase in the X-ray buildup region, and on the PDD decrease in the electron beam target region should be paid much more attention. And the dose distribution, with an added mask, will have to be re-evaluated in 3-D conformal radiotherapy

Rapid Processing of Net-Shape Thermoplastic Planar-Random Composite Preforms

Science.gov (United States)

Jespersen, S. T.; Baudry, F.; Schmäh, D.; Wakeman, M. D.; Michaud, V.; Blanchard, P.; Norris, R. E.; Månson, J.-A. E.

2009-02-01

A novel thermoplastic composite preforming and moulding process is investigated to target cost issues in textile composite processing associated with trim waste, and the limited mechanical properties of current bulk flow-moulding composites. The thermoplastic programmable powdered preforming process (TP-P4) uses commingled glass and polypropylene yarns, which are cut to length before air assisted deposition onto a vacuum screen, enabling local preform areal weight tailoring. The as-placed fibres are heat-set for improved handling before an optional preconsolidation stage. The preforms are then preheated and press formed to obtain the final part. The process stages are examined to optimize part quality and throughput versus processing parameters. A viable processing route is proposed with typical cycle times below 40 s (for a plate 0.5 × 0.5 m2, weighing 2 kg), enabling high production capacity from one line. The mechanical performance is shown to surpass that of 40 wt.% GMT and has properties equivalent to those of 40 wt.% GMTex at both 20°C and 80°C.

PZT/PLZT - elastomer composites with improved piezoelectric voltage coefficient

Science.gov (United States)

Harikrishnan, K.; Bavbande, D. V.; Mohan, Dhirendra; Manoharan, B.; Prasad, M. R. S.; Kalyanakrishnan, G.

2018-02-01

Lead Zirconate Titanate (PZT) and Lanthanum-modified Lead Zirconate Titanate (PLZT) ceramic sensor materials are widely used because of their excellent piezoelectric coefficients. These materials are brittle, high density and have low achievable piezoelectric voltage coefficients. The density of the sintered ceramics shall be reduced by burnable polymeric sponge method. The achievable porosity level in this case is nearly 60 - 90%. However, the porous ceramic structure with 3-3 connectivity produced by this method is very fragile in nature. The strength of the porous structure is improved with Sylgard®-184 (silicone elastomer) by vacuum impregnation method maintaining the dynamic vacuum level in the range of -650 mm Hg. The elastomer Sylgard®-184 is having low density, low dielectric constant and high compliance (as a resultant stiffness of the composites is increased). To obtain a net dipole moment, the impregnated ceramic composites were subjected to poling treatment with varying conditions of D.C. field and temperature. The properties of the poled PZT/PLZT - elastomer composites were characterized with LCR meter for measuring the dielectric constant values (k), d33 meter used for measuring piezo-electric charge coefficient values (d33) and piezo-electric voltage coefficient (g33) values which were derived from d33 values. The voltage coefficient (g33) values of these composites are increased by 10 fold as compared to the conventional solid ceramics demonstrates that it is possible to fabricate a conformable detector.

High-temperature hybrid welding of thermoplastic (CF/Peek) to thermoset (CF/Epoxy) composites

NARCIS (Netherlands)

Fernandez Villegas, I.; Vizcaino Rubio, P.

2015-01-01

Thermoset composites are widely used for the manufacturing of modern composite aircrafts. The use of thermoplastic composites (TPC) in aerospace applications is, however, gradually increasing owing to their cost-effectiveness in manufacturing and improved damage tolerance. An example of the use of

Green composites of thermoplastic corn starch and recycled paper cellulose fibers

Directory of Open Access Journals (Sweden)

Amnuay Wattanakornsiri

2011-08-01

Full Text Available Ecological concerns have resulted in a renewed interest in environmental-friendly composites issues for sustainabledevelopment as a biodegradable renewable resource. In this work we used cellulose fibers from recycled newspaper as reinforcementfor thermoplastic starch in order to improve its mechanical, thermal and water resistance properties. The compositeswere prepared from corn starch plasticized by glycerol (30% wt/wt of glycerol to starch as matrix that was reinforcedwith micro-cellulose fibers, obtained from used newspaper, with fiber content ranging from 0 to 8% (wt/wt of fibers to matrix.Physical properties of composites were determined by mechanical tensile tests, differential scanning calorimetry, thermogravimetricanalysis, water absorption measurement and scanning electron microscopy. The results showed that higherfibers content raised the tensile strength and elastic modulus up to 175% and 292%, respectively, when compared to thenon-reinforced thermoplastic starch. The addition of the fibers improved the thermal resistance and decreased the waterabsorption up to 63%. Besides, scanning electron microscopy illustrated a good adhesion between matrix and fibers. Theseresults indicated that thermoplastic starch reinforced with recycled newspaper cellulose fibers could be fruitfully used ascommodity plastics being strong, cheap, abundant and recyclable.

Reliability in maintenance and design of elastomer sealed closures

International Nuclear Information System (INIS)

Lake, W.H.

1978-01-01

The methods of reliability are considered for maintenance and design of elastomer sealed containment closures. Component reliability is used to establish a replacement schedule for system maintenance. Reliability data on elastomer seals is used to evaluate the common practice of annual replacement, and to calculate component reliability values for several typical shipment time periods. System reliability methods are used to examine the relative merits of typical closure designs. These include single component and redundant seal closure, with and without closure verification testing. The paper presents a general method of quantifying the merits of closure designs through the use of reliability analysis, which is a probabilistic technique. The reference list offers a general source of information in the field of reliability, and should offer the opportunity to extend the procedures discussed in this paper to other design safety applications

Evaluation of a Thermoplastic Immobilization System for Breast and Chest Wall Radiation Therapy

International Nuclear Information System (INIS)

Strydhorst, Jared H.; Caudrelier, Jean-Michel; Clark, Brenda G.; Montgomery, Lynn A.; Fox, Greg; MacPherson, Miller S.

2011-01-01

We report on the impact of a thermoplastic immobilization system on intra- and interfraction motion for patients undergoing breast or chest wall radiation therapy. Patients for this study were treated using helical tomotherapy. All patients were immobilized using a thermoplastic shell extending from the shoulders to the ribcage. Intrafraction motion was assessed by measuring maximum displacement of the skin, heart, and chest wall on a pretreatment 4D computed tomography, while inter-fraction motion was inferred from patient shift data arising from daily image guidance procedures on tomotherapy. Using thermoplastic immobilization, the average maximum motion of the external contour was 1.3 ± 1.6 mm, whereas the chest wall was found to be 1.6 ± 1.9 mm. The day-to-day setup variation was found to be large, with random errors of 4.0, 12.0, and 4.5 mm in the left-right, superior-inferior, and anterior-posterior directions, respectively, and the standard deviations of the systematic errors were found to be 2.7, 9.8, and 4.1 mm. These errors would be expected to dominate any respiratory motion but can be mitigated by daily online image guidance. Using thermoplastic immobilization can effectively reduce respiratory motion of the chest wall and external contour, but these gains can only be realized if daily image guidance is used.

Materials, Mechanics, and Patterning Techniques for Elastomer-Based Stretchable Conductors

Directory of Open Access Journals (Sweden)

Xiaowei Yu

2016-12-01

Full Text Available Stretchable electronics represent a new generation of electronics that utilize soft, deformable elastomers as the substrate or matrix instead of the traditional rigid printed circuit boards. As the most essential component of stretchable electronics, the conductors should meet the requirements for both high conductivity and the capability to maintain conductive under large deformations such as bending, twisting, stretching, and compressing. This review summarizes recent progresses in various aspects of this fascinating and challenging area, including materials for supporting elastomers and electrical conductors, unique designs and stretching mechanics, and the subtractive and additive patterning techniques. The applications are discussed along with functional devices based on these conductors. Finally, the review is concluded with the current limitations, challenges, and future directions of stretchable conductors.

Mechanical and Electrical Ageing Effects on the Long-Term Stretching of Silicone Dielectric Elastomers with Soft Fillers

DEFF Research Database (Denmark)

Madsen, Frederikke Bahrt; Zakaria, Shamsul Bin; Yu, Liyun

2016-01-01

Dielectric elastomer materials for actuators need to be soft and stretchable while possessing high dielectric permittivity. Soft silicone elastomers can be obtained through the use of silicone oils, while enhanced permittivity can be obtained through the use of dipolar groups on the polymer backb...

Polypropylene/elastomers/organophilic bentonite nanocomposites. Influence of elastomer content on morphology and mechanical properties

International Nuclear Information System (INIS)

Ferreira, K.R.M.; Braga, C.R.C.; Andrade, D.L.A.C.S.; Carvalho, L.H.; Silva, S.M.L.

2010-01-01

In this study, the effect of the elastomer terpolymer ethylene-propylene-diene (EPDM) content on the morphology and mechanical properties of polypropylene PP/EPDM/organophilic bentonite nanocomposite was evaluated. The bentonite, supplied by Bentonit Uniao Nordeste, was purified and organically modified with cetyl trimethyl quaternary ammonium (cetremide) before the incorporation in PP/EPDM blend. The blends with various amounts of EPDM (10, 20, 30 and 40 wt%) and 1 phr of organoclay were prepared by melt-blending at 180 deg C and 50 rpm for 15 min with an internal mixer (Haake). The blends were characterized by X-ray diffraction and mechanical properties (tensile strength). According to the results, we concluded that the content of EPDM affected the morphology and mechanical properties of nanocomposites resulting in improvement in mechanical and morphological properties when a content of 30 wt% of EPDM was used. (author)

Mechanical properties of green composites based on thermoplastic starch

Science.gov (United States)

Fornes, F.; Sánchez-Nácher, L.; Fenollar, O.; Boronat, T.; Garcia-Sanoguera, D.

2010-06-01

The present work is focused on study of "green composites" elaborated from thermoplastic starch (TPS) as polymer matrix and a fiber from natural origin (rush) as reinforced fiber. The effect of the fiber content has been studied by means of the mechanical properties. The composite resulting presents a lack of interaction between matrix and fiber that represents a performance decrease. However the biodegradability behavior of the resulting composite raise this composite as useful an industrial level.

Phenomena of nonlinear oscillation and special resonance of a dielectric elastomer minimum energy structure rotary joint

Science.gov (United States)

Zhao, Jianwen; Niu, Junyang; McCoul, David; Ren, Zhi; Pei, Qibing

2015-03-01

The dielectric elastomer minimum energy structure can realize large angular deformations by a small voltage-induced strain of the dielectric elastomer, so it is a suitable candidate to make a rotary joint for a soft robot. Driven with an alternating electric field, the joint deformation vibrational frequency follows the input voltage frequency. However, the authors find that if the rotational inertia increases such that the inertial torque makes the frame deform over a negative angle, then the joint motion will become complicated and the vibrational mode will alter with the change of voltage frequency. The vibration with the largest amplitude does not occur while the voltage frequency is equal to natural response frequency of the joint. Rather, the vibrational amplitude will be quite large over a range of other frequencies at which the vibrational frequency is half of the voltage frequency. This phenomenon was analyzed by a comparison of the timing sequences between voltage and joint vibration. This vibrational mode with the largest amplitude can be applied to the generation lift in a flapping wing actuated by dielectric elastomers.

Changes in the mechanical properties of thermoplastic potato starch in relation with changes in B-type crystallinity

NARCIS (Netherlands)

Vliegenthart, J.F.G.; Soest, J.J.G. van; Hulleman, S.H.D.; Wit, D. de

1996-01-01

The influence of crystallization on the stress-strain behaviour of thermoplastic potato starch has been monitored. Potato starch has been processed by extrusion with glycerol and water added as plasticizers. The thermoplastic starch consists of a molecular network of semicrystalline amylose and

Thermoplastic starch/ethylene vinyl alcohol/forsterite nanocomposite as a candidate material for bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Mahdieh, Zahra [Polymeric Materials Research Group (PMRG), Department of Materials Science and Engineering, Sharif University of Technology, Tehran, P.O. Box 11155-9466 (Iran, Islamic Republic of); Bagheri, Reza, E-mail: rezabagh@sharif.edu [Polymeric Materials Research Group (PMRG), Department of Materials Science and Engineering, Sharif University of Technology, Tehran, P.O. Box 11155-9466 (Iran, Islamic Republic of); Eslami, Masoud; Amiri, Mohammad [Polymeric Materials Research Group (PMRG), Department of Materials Science and Engineering, Sharif University of Technology, Tehran, P.O. Box 11155-9466 (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali; Mehrjoo, Morteza [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of)

2016-12-01

Recently, biodegradable polymers such as starch based blends have been well renowned in the biomedical field. Studies have considered them suitable for bone scaffolds, bone cements, tissue engineering scaffolds, drug delivery systems and hydrogels. The aim of this study was to synthesize nanocomposite biomaterial consisting a blend of thermoplastic starch and ethylene vinyl alcohol as the polymer matrix, and nano-structured forsterite as the ceramic reinforcing phase for bone tissue engineering applications. Furthermore, vitamin E was applied as a thermal stabilizer during melt compounding. Extrusion and injection molding were incorporated for melt blending and shaping of samples, respectively. With blending thermoplastic starch and ethylene vinyl alcohol, some properties of thermoplastic starch such as degradation rate and water absorption were modified. In addition, using nanoforsterite as the ceramic reinforcing phase resulted in the improvement of mechanical and biological traits. The addition of nanoforsterite decreased the weight loss of the thermoplastic starch and ethylene vinyl alcohol blend in simulated body fluid. Moreover, this addition modified the pH in the MTT (methyl thiazolyl tetrazolium) assay and stimulated the cell proliferation. Cell adhesion assays indicated a favorable interaction between cells and the biomaterial. The proposed nanocomposite has appropriate biocompatibility, as well as mechanical properties in order to be used in bone tissue engineering. - Highlights: • A biodegradable nanocomposite is proposed for orthopedic applications. • Vitamin E is used as an antioxidant to prevent the thermomechanical degradations. • Nanoforsterite reduced the composite degradation rate in the simulated body fluid. • Nanoforsterite modified pH in MTT assay and stimulated cell proliferation.

Thermoplastic starch/ethylene vinyl alcohol/forsterite nanocomposite as a candidate material for bone tissue engineering

International Nuclear Information System (INIS)

Mahdieh, Zahra; Bagheri, Reza; Eslami, Masoud; Amiri, Mohammad; Shokrgozar, Mohammad Ali; Mehrjoo, Morteza

2016-01-01

Recently, biodegradable polymers such as starch based blends have been well renowned in the biomedical field. Studies have considered them suitable for bone scaffolds, bone cements, tissue engineering scaffolds, drug delivery systems and hydrogels. The aim of this study was to synthesize nanocomposite biomaterial consisting a blend of thermoplastic starch and ethylene vinyl alcohol as the polymer matrix, and nano-structured forsterite as the ceramic reinforcing phase for bone tissue engineering applications. Furthermore, vitamin E was applied as a thermal stabilizer during melt compounding. Extrusion and injection molding were incorporated for melt blending and shaping of samples, respectively. With blending thermoplastic starch and ethylene vinyl alcohol, some properties of thermoplastic starch such as degradation rate and water absorption were modified. In addition, using nanoforsterite as the ceramic reinforcing phase resulted in the improvement of mechanical and biological traits. The addition of nanoforsterite decreased the weight loss of the thermoplastic starch and ethylene vinyl alcohol blend in simulated body fluid. Moreover, this addition modified the pH in the MTT (methyl thiazolyl tetrazolium) assay and stimulated the cell proliferation. Cell adhesion assays indicated a favorable interaction between cells and the biomaterial. The proposed nanocomposite has appropriate biocompatibility, as well as mechanical properties in order to be used in bone tissue engineering. - Highlights: • A biodegradable nanocomposite is proposed for orthopedic applications. • Vitamin E is used as an antioxidant to prevent the thermomechanical degradations. • Nanoforsterite reduced the composite degradation rate in the simulated body fluid. • Nanoforsterite modified pH in MTT assay and stimulated cell proliferation.

Nanoindentation study of interphases in epoxy/amine thermosetting systems modified with thermoplastics.

Science.gov (United States)

Ramos, Jose Angel; Blanco, Miren; Zalakain, Iñaki; Mondragon, Iñaki

2009-08-15

The characterization of a mixture of epoxy/amine with different stoichiometric ratios was carried out by means of nanoindentation. The epoxy system was composed by diglycidyl ether of bisphenol-A and 4,4'-methylene bis-(3-chloro 2,6-diethylaniline). Diffusion through interface formed by epoxy/amine system in stoichiometric ratio and several thermoplastic polymers was also analyzed by means of stiffness analysis, as studied by atomic force microscopy (AFM) and coupled nanoindentation tests. Used thermoplastics were an amorphous, atactic polystyrene, and two semicrystalline, syndiotactic polystyrene and poly(phenylene sulfide). Larger range diffusion was obtained in epoxy/amine systems modified with atactic polystyrene while the study of the influence of stoichiometric ratio suggests that the excess of epoxy generated stiffer material. In addition, larger indentation loads resulted in higher apparent stiffness because of the more number of polymer chains that had to re-accommodate owing to the increase in contact area.

Solvent Bonding for Fabrication of PMMA and COP Microfluidic Devices.

Science.gov (United States)

Wan, Alwin M D; Moore, Thomas A; Young, Edmond W K

2017-01-17

Thermoplastic microfluidic devices offer many advantages over those made from silicone elastomers, but bonding procedures must be developed for each thermoplastic of interest. Solvent bonding is a simple and versatile method that can be used to fabricate devices from a variety of plastics. An appropriate solvent is added between two device layers to be bonded, and heat and pressure are applied to the device to facilitate the bonding. By using an appropriate combination of solvent, plastic, heat, and pressure, the device can be sealed with a high quality bond, characterized as having high bond coverage, bond strength, optical clarity, durability over time, and low deformation or damage to microfeature geometry. We describe the procedure for bonding devices made from two popular thermoplastics, poly(methyl-methacrylate) (PMMA), and cyclo-olefin polymer (COP), as well as a variety of methods to characterize the quality of the resulting bonds, and strategies to troubleshoot low quality bonds. These methods can be used to develop new solvent bonding protocols for other plastic-solvent systems.

Semi-active variable stiffness vibration control of vehicle seat suspension using an MR elastomer isolator

International Nuclear Information System (INIS)

Du, Haiping; Li, Weihua; Zhang, Nong

2011-01-01

This paper presents a study on continuously variable stiffness control of vehicle seat suspension using a magnetorheological elastomer (MRE) isolator. A concept design for an MRE isolator is proposed in the paper and its behavior is experimentally evaluated. An integrated seat suspension model, which includes a quarter-car suspension and a seat suspension with a driver body model, is used to design a sub-optimal H ∞ controller for an active isolator. The desired control force generated by this active isolator is then emulated by the MRE isolator through its continuously variable stiffness property when the actuating condition is met. The vibration control effect of the MRE isolator is evaluated in terms of driver body acceleration responses under both bump and random road conditions. The results show that the proposed control strategy achieves better vibration reduction performance than conventional on–off control

Energy scavenging strain absorber: application to kinetic dielectric elastomer generator

Science.gov (United States)

Jean-Mistral, C.; Beaune, M.; Vu-Cong, T.; Sylvestre, A.

2014-03-01

Dielectric elastomer generators (DEGs) are light, compliant, silent energy scavengers. They can easily be incorporated into clothing where they could scavenge energy from the human kinetic movements for biomedical applications. Nevertheless, scavengers based on dielectric elastomers are soft electrostatic generators requiring a high voltage source to polarize them and high external strain, which constitutes the two major disadvantages of these transducers. We propose here a complete structure made up of a strain absorber, a DEG and a simple electronic power circuit. This new structure looks like a patch, can be attached on human's wear and located on the chest, knee, elbow… Our original strain absorber, inspired from a sailing boat winch, is able to heighten the external available strain with a minimal factor of 2. The DEG is made of silicone Danfoss Polypower and it has a total area of 6cm per 2.5cm sustaining a maximal strain of 50% at 1Hz. A complete electromechanical analytical model was developed for the DEG associated to this strain absorber. With a poling voltage of 800V, a scavenged energy of 0.57mJ per cycle is achieved with our complete structure. The performance of the DEG can further be improved by enhancing the imposed strain, by designing a stack structure, by using a dielectric elastomer with high dielectric permittivity.

Polymer-filler interactions in polyether based thermoplastic polyureathane/silica nanocomposites

OpenAIRE

Heinz, Özge; Heinz, Ozge

2013-01-01

Thermoplastic polyurethaneureas (TPU) are a unique class of materials that are used in a broad range of applications due to their tailorable chemistry and morphology that allow engineering materials with targeted properties. The central theme of this dissertation is to develop an understanding on polymer-filler interfacial interactions and related reinforcing mechanism of silica nanoparticles in polyether based TPU/silica nanocomposites. Prior to our investigation on nanocomposite materials, ...

Actuation response of polyacrylate dielectric elastomers

DEFF Research Database (Denmark)

Kofod, G.; Kornbluh, R.; Pelrine, R.

2001-01-01

Polyacrylate dielectric elastomers have yielded extremely large strain and elastic energy density suggesting that they are useful for many actuator applications. A thorough understanding of the physics underlying the mechanism of the observed response to an electric field can help develop improved......, though there are discrepancies. Further analysis suggests that these arise mostly from imperfect manufacture of the actuators, though there is a small contribution from an explicitly electrostrictive behavior of the acrylic adhesive. Measurements of the dielectric constant of stretched polymer reveal...... that the dielectric constant drops, when the polymer is strained, indicating the existence of a small electrostrictive effect. Finally, measurements of the electric breakdown field were made. These also show a dependence upon the strain. In the unstrained state the breakdown field is 20 WV/m, which grows to 218MV...

Ultrasonic Welding of Thermoplastic Composite Coupons for Mechanical Characterization of Welded Joints through Single Lap Shear Testing.

Science.gov (United States)

Villegas, Irene F; Palardy, Genevieve

2016-02-11

This paper presents a novel straightforward method for ultrasonic welding of thermoplastic-composite coupons in optimum processing conditions. The ultrasonic welding process described in this paper is based on three main pillars. Firstly, flat energy directors are used for preferential heat generation at the joining interface during the welding process. A flat energy director is a neat thermoplastic resin film that is placed between the parts to be joined prior to the welding process and heats up preferentially owing to its lower compressive stiffness relative to the composite substrates. Consequently, flat energy directors provide a simple solution that does not require molding of resin protrusions on the surfaces of the composite substrates, as opposed to ultrasonic welding of unreinforced plastics. Secondly, the process data provided by the ultrasonic welder is used to rapidly define the optimum welding parameters for any thermoplastic composite material combination. Thirdly, displacement control is used in the welding process to ensure consistent quality of the welded joints. According to this method, thermoplastic-composite flat coupons are individually welded in a single lap configuration. Mechanical testing of the welded coupons allows determining the apparent lap shear strength of the joints, which is one of the properties most commonly used to quantify the strength of thermoplastic composite welded joints.

Phase transitions in blends functionalized thermoplastics

International Nuclear Information System (INIS)

Grigoryeva, O.; Sergeeva, L.; Starostenko, O.; Pissis, P.

2001-01-01

Phase transitions, morphology and structure-property relationships in polymer blends based on functionalized thermoplastics, i.e. widely used polyurethanes and styrene-acrylic acid copolymers, were investigated by means of inter-expletive non-destructive methods. Wide and small angle X-ray scattering (WAXS and SAXS), dynamic mechanical thermal analysis, thermally stimulated depolarization currents techniques, dielectric relaxation spectroscopy and several physico-mechanical characterization techniques were used. The results obtained by the various techniques were critically compared to each other. (author)

Investigations on laser transmission welding of absorber-free thermoplastics

Science.gov (United States)

Mamuschkin, Viktor; Olowinsky, Alexander; Britten, Simon W.; Engelmann, Christoph

2014-03-01

Within the plastic industry laser transmission welding ranks among the most important joining techniques and opens up new application areas continuously. So far, a big disadvantage of the process was the fact that the joining partners need different optical properties. Since thermoplastics are transparent for the radiation of conventional beam sources (800- 1100 nm) the absorbance of one of the joining partners has to be enhanced by adding an infrared absorber (IR-absorber). Until recently, welding of absorber-free parts has not been possible. New diode lasers provide a broad variety of wavelengths which allows exploiting intrinsic absorption bands of thermoplastics. The use of a proper wavelength in combination with special optics enables laser welding of two optically identical polymer parts without absorbers which can be utilized in a large number of applications primarily in the medical and food industry, where the use of absorbers usually entails costly and time-consuming authorization processes. In this paper some aspects of the process are considered as the influence of the focal position, which is crucial when both joining partners have equal optical properties. After a theoretical consideration, an evaluation is carried out based on welding trials with polycarbonate (PC). Further aspects such as gap bridging capability and the influence of thickness of the upper joining partner are investigated as well.

Superhydrophobic/superoleophilic magnetic elastomers by laser ablation

Energy Technology Data Exchange (ETDEWEB)

Milionis, Athanasios, E-mail: am2vy@virginia.edu [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Fragouli, Despina; Brandi, Fernando; Liakos, Ioannis; Barroso, Suset [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Ruffilli, Roberta [Nanochemistry, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Athanassiou, Athanassia, E-mail: athanassia.athanassiou@iit.it [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy)

2015-10-01

Highlights: • We report the development of magnetic nanocomposite sheets. • Laser irradiation of the nanocomposites induces chemical and structural changes to the surface. • The laser-patterned surfaces exhibit superhydrophobicity and superoleophilicity. • The particle contribution in altering the surface and bulk properties of the material is studied. - Abstract: We report the development of magnetic nanocomposite sheets with superhydrophobic and supeoleophilic surfaces generated by laser ablation. Polydimethylsiloxane elastomer free-standing films, loaded homogeneously with 2% wt. carbon coated iron nanoparticles, were ablated by UV (248 nm), nanosecond laser pulses. The laser irradiation induces chemical and structural changes (both in micro- and nano-scale) to the surfaces of the nanocomposites rendering them superhydrophobic. The use of nanoparticles increases the UV light absorption efficiency of the nanocomposite samples, and thus facilitates the ablation process, since the number of pulses and the laser fluence required are greatly reduced compared to the bare polymer. Additionally the magnetic nanoparticles enhance significantly the superhydrophobic and oleophilic properties of the PDMS sheets, and provide to PDMS magnetic properties making possible its actuation by a weak external magnetic field. These nanocomposite elastomers can be considered for applications requiring magnetic MEMS for the controlled separation of liquids.

The dynamic contact area of elastomers at different velocities

NARCIS (Netherlands)

Khafidh, Muhammad; Rodriguez, N.V.; Masen, Marc Arthur; Schipper, Dirk J.

2016-01-01

The friction in tribo-systems that contain viscoelastic materials, such as elastomers, is relevant for a large number of applications. Examples include tyres, hoses, transmission and conveyor belts. To quantify the friction in these applications, one must first understand the contact behaviour of

Polycarbonate-based polyurethane elastomers: temperature-dependence of tensile properties

Czech Academy of Sciences Publication Activity Database

Hrdlička, Z.; Kuta, A.; Poreba, Rafal; Špírková, Milena

2014-01-01

Roč. 68, č. 2 (2014), s. 233-238 ISSN 0366-6352 R&D Projects: GA ČR GAP108/10/0195 Institutional support: RVO:61389013 Keywords : polyurethane * elastomer * polycarbonate diol Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.468, year: 2014

Characterization of Ferrofluid-based Stimuli-responsive Elastomers

OpenAIRE

Sandra dePedro; Xavier Munoz-Berbel; Rosalia Rodríguez-Rodríguez; Jordi Sort; Jose Antonio Plaza; Juergen Brugger; Andreu Llobera; Victor J Cadarso

2016-01-01

Stimuli-responsive materials undergo physicochemical and/or structural changes when a specific actuation is applied. They are heterogeneous composites, consisting of a non-responsive matrix where functionality is provided by the filler. Surprisingly, the synthesis of polydimethylsiloxane (PDMS)-based stimuli-responsive elastomers (SRE) has seldomly been presented. Here, we present the structural, biological, optical, magnetic, and mechanical properties of several magnetic SRE (M-SRE) obtained...

Comparison between properties of polyurethane nano composites prepared by two different methods

International Nuclear Information System (INIS)

Barmar, M.; Barikani, M.; Fereidoonnia, M.

2009-01-01

In this work, a thermoplastic polyurethane elastomer model based on polytetramethylene glycol. toluene diisocyanate and 1,4-butanediol was selected and synthesized. According to this model two types of polyurethane nano composites were prepared by in situ polymerization and melt intercalation procedures. The organo-modified nano clay was used in nano composites samples in 0.4 weight percent level. The prepared nano composites were studied by WAXD, tensile and thermal analysis. Thermal properties of the nano composites were higher than those of pure polyurethane elastomers. Nano composites prepared via melt intercalation method showed a lower tensile strength and hardness than those prepared through in situ polymerization method

Converters and electric machines. Solid insulating materials. Electrical characteristics; Convertisseurs et machines electriques. Materiaux isolants solides. Caracteristiques electriques

Energy Technology Data Exchange (ETDEWEB)

Anton, A. [Institut National Superieur de Chimie Industrielle, 76 - Rouen (France)

2003-08-01

The aim of this article is to allow a preselection of a solid insulating material using the most common electrical characteristics: tangent of the loss angle, relative permittivity, dielectric rigidity, superficial resistivity, transverse resistivity, resistance to high voltage creeping spark currents, index of creeping resistance. The characteristics of the main solid insulating materials are presented in tables for: thermoplastics, thermosetting materials, natural insulating materials, mineral insulating materials, rubber and synthetic elastomers, stratified insulating materials, thermoplastic films, composite synthetic papers. A comparison is made between the different materials using the three properties: tangent of the loss angle, relative permittivity and resistance to HV spark creeping currents. (J.S.)

Detecting onset of chain scission and crosslinking of γ-ray irradiated elastomer surfaces using frictional force microscopy

International Nuclear Information System (INIS)

Banerjee, S; Sinha, N K; Gayathri, N; Ponraju, D; Dash, S; Tyagi, A K; Raj, Baldev

2007-01-01

We report here that atomic force microscopy (AFM) in frictional force mode can be used to detect the onset of chain scission and crosslinking in polymeric and macromolecular samples upon irradiation. A systematic investigation to detect chain scission and crosslinking of two elastomers (1) ethylene-propylene-diene monomer rubber and (2) fluorocarbon rubber, upon γ-ray irradiation has been carried out using frictional force microscopy (FFM). From the AFM results we observed that both the elastomers show a systematic smoothening of its surfaces, as the γ-ray dose rate increases. However, the frictional property studied using FFM of the sample surfaces show an initial increase and then a decrease as a function of dose rate. This behaviour of increase in its frictional property has been attributed to the onset of chain scission, and the subsequent decrease in friction has been attributed to the onset of crosslinking of the polymer chains. The evaluated qualitative and semi-quantitative changes observed in the overall frictional property as a function of the γ-ray dose rate for the two elastomers are presented in this paper

3D Printing of Highly Stretchable, Shape-Memory, and Self-Healing Elastomer toward Novel 4D Printing.

Science.gov (United States)

Kuang, Xiao; Chen, Kaijuan; Dunn, Conner K; Wu, Jiangtao; Li, Vincent C F; Qi, H Jerry

2018-02-28

The three-dimensional (3D) printing of flexible and stretchable materials with smart functions such as shape memory (SM) and self-healing (SH) is highly desirable for the development of future 4D printing technology for myriad applications, such as soft actuators, deployable smart medical devices, and flexible electronics. Here, we report a novel ink that can be used for the 3D printing of highly stretchable, SM, and SH elastomer via UV-light-assisted direct-ink-write printing. An ink containing urethane diacrylate and a linear semicrystalline polymer is developed for the 3D printing of a semi-interpenetrating polymer network elastomer that can be stretched by up to 600%. The 3D-printed complex structures show interesting functional properties, such as high strain SM and SM -assisted SH capability. We demonstrate that such a 3D-printed SM elastomer has the potential application for biomedical devices, such as vascular repair devices. This research paves a new way for the further development of novel 4D printing, soft robotics, and biomedical devices.

Detecting onset of chain scission and crosslinking of {gamma}-ray irradiated elastomer surfaces using frictional force microscopy

Energy Technology Data Exchange (ETDEWEB)

Banerjee, S [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Sinha, N K [Innovative Design Engineering and Synthesis Section, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Gayathri, N [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Ponraju, D [Radiological Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Dash, S [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Tyagi, A K [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India); Raj, Baldev [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 TN (India)

2007-02-07

We report here that atomic force microscopy (AFM) in frictional force mode can be used to detect the onset of chain scission and crosslinking in polymeric and macromolecular samples upon irradiation. A systematic investigation to detect chain scission and crosslinking of two elastomers (1) ethylene-propylene-diene monomer rubber and (2) fluorocarbon rubber, upon {gamma}-ray irradiation has been carried out using frictional force microscopy (FFM). From the AFM results we observed that both the elastomers show a systematic smoothening of its surfaces, as the {gamma}-ray dose rate increases. However, the frictional property studied using FFM of the sample surfaces show an initial increase and then a decrease as a function of dose rate. This behaviour of increase in its frictional property has been attributed to the onset of chain scission, and the subsequent decrease in friction has been attributed to the onset of crosslinking of the polymer chains. The evaluated qualitative and semi-quantitative changes observed in the overall frictional property as a function of the {gamma}-ray dose rate for the two elastomers are presented in this paper.

High-pressure needle interface for thermoplastic microfluidics.

Science.gov (United States)

Chen, C F; Liu, J; Hromada, L P; Tsao, C W; Chang, C C; DeVoe, D L

2009-01-07

A robust and low dead volume world-to-chip interface for thermoplastic microfluidics has been developed. The high pressure fluidic port employs a stainless steel needle inserted into a mating hole aligned to an embedded microchannel, with an interference fit used to increase pressure resistance. Alternately, a self-tapping threaded needle screwed into a mating hole is also demonstrated. In both cases, the flat bottom needle ports seat directly against the microchannel substrate, ensuring low interfacial dead volumes. Low dispersion is observed for dye bands passing the interfaces. The needle ports offer sufficient pull-out forces for applications such as liquid chromatography that require high internal fluid pressures, with the epoxy-free interfaces compatible with internal microchannel pressures above 40 MPa.

New approach to improve the energy density of hybrid electret-dielectric elastomer generators

Science.gov (United States)

Lagomarsini, Clara; Jean-Mistral, Claire; Monfray, Stephane; Sylvestre, Alain

2017-04-01

Harvesting human kinetic energy to produce electricity is an attractive alternative to batteries for applications in wearable electronic devices and smart textile. Dielectric elastomers generators (DEGs) represent one of the most promising technologies for these applications. Nevertheless, one of the main disadvantages of these structures is the need of an external polarization source to perform the energetic cycle. In the present work, a hybrid electret-dielectric elastomer generator in DEG mode is presented. In this configuration, the electret material is used as polarization source of a classical DEG, i.e. an electrostatic generator based on electrical capacitance variation. The electrical energy output in this mode (1.06mJ.g-1) could be higher than the one obtained using a classical electret mode (0.55mJ.g-1), i.e. charges recombination. In this paper, the operation principle of the hybrid generator will be fully described and the design rules for the realization of the prototype will be presented. The experimental data obtained from the prototype will be compared to the results of FEM simulations.

Steady shear characteristic and behavior of magneto-thermo-elasticity of isotropic MR elastomers

International Nuclear Information System (INIS)

Gao, Wei; Wang, Xingzhe

2016-01-01

The magneto-thermo-elastic steady shear behaviors of isotropic smart composites of silicon rubber matrix randomly filled with ferromagnetic particles, commonly referred to as magnetorheological (MR) elastomers, are investigated experimentally and theoretically in the present study. The strip specimens of the MR elastomer composite with different ferromagnetic particle concentrations are fabricated and implemented for lap-shear tests under both magnetic and thermal fields. It is illustrated that the magneto-thermo-elastic shear modulus of the MR elastomer is markedly enhanced with the volume fraction of ferromagnetic particles and the applied external magnetic field, while the shear modulus is decreased with the environment temperature. To qualitatively elucidate the magneto-thermo-elastic shear performance of this kind of magnetic smart composites, a modified constitutive of hyperelasticity is suggested taking into account the influence of magnetic field and temperature on the magnetic potential energy and strain energy. The theoretical modeling predictions on the stress–strain behaviors for different applied magnetic fields and environment temperatures are compared to experimental observations to demonstrate a good agreement. (paper)

Characterizing the influence of matrix ductility on damage phenomenology in continuous fiber-reinforced thermoplastic laminates undergoing quasi-static indentation

KAUST Repository

Yudhanto, Arief; Wafai, Husam; Lubineau, Gilles; Yaldiz, R.; Verghese, N.

2017-01-01

The use of thermoplastic matrix was known to improve the impact properties of laminated composites. However, different ductility levels can exist in a single family of thermoplastic matrix, and this may consequently modify the damage phenomenology

Variation of mechanical and thermal properties of the thermoplastics reinforced with natural fibers by electron beam processing

Energy Technology Data Exchange (ETDEWEB)

Kim, Sok Won [Department of Physics, University of Ulsan, Ulsan 680 749 (Korea, Republic of)], E-mail: sokkim@ulsan.ac.kr; Oh, Seungmin; Lee, Kyuse [Ilkwang Co. Ltd. 1178-6 Goyon-ri, Ungchon-mueon, Ulju-gun 689 871 (Korea, Republic of)

2007-11-15

With restrictions for environmental protection being strengthened, the thermoplastics reinforced with natural fibers (NFs) such as jute, kenaf, flax, etc., appeared as an automobile interior material instead of the chemical plastics. Regardless of many advantages, one shortcoming is the deformation after being formed in high temperature of about 200 deg. C, caused by the poor adhesion between the natural fibers and thermoplastics. Also, the energy saving in connection with car air-conditioning becomes very important. In this study, the thermal conductivity, tensile strength, and deformation of several kinds of thermoplastic composites composing of 50% polypropylene (PP) and 50% natural fiber irradiated by the electron beam (energy: 0.5 MeV, dose: 0-20 kGy) were measured. The length and thickness of PP and NF are 80{+-}10 mm and 40-120 {mu}m, respectively. The results show that the thermal conductivity and the tensile strength changed and became minimum when the dose of electron beam is 10 kGy, and the deformation after the thermal cycle were reduced by the electron beam.

Non-contact inline monitoring of thermoplastic CFRP tape quality using air-coupled ultrasound

Science.gov (United States)

Essig, W.; Fey, P.; Meiler, S.; Kreutzbruck, M.

2017-02-01

Beginning with the aerospace industry, fiber reinforced plastics have spread towards many applications such as automotive, civil engineering as well as sports and leisure articles. Their superior strength and stiffness to mass ratio made them the number one material for achieving high performance. Especially continuous fiber reinforced plastics allow for the construction of structures which are custom tailored to their mechanical loads by adjusting the paths of the fibers to the loading direction. The two main constituents of CFRP are carbon fibers and matrix. Two possibilities for matrix material exist: thermosetting and thermoplastic matrix. While thermosetting matrix may yield better properties with respect to thermal loads, thermoplasticity opens a wide range of applications due to weldability, shapeability, and compatibility to e.g. injection molded thermoplastic materials. Thin (0.1 mm) thermoplastic continuous fiber CFRP tapes with a width of 100 mm were examined using air-coupled ultrasound. Transducers were arranged in reflection as well as transmission setup. By slanted incidence of the ultrasound on the tape surface, guided waves were excited in the material in fiber direction and perpendicular to the fiber direction. Artificial defects - fiber cuts, matrix cuts, circular holes, low velocity impacts from tool drop, and sharp bends - were produced. Experiments on a stationary tape showed good detectability of all artificial defects by guided waves. Also the effects of variation in material properties, fiber volume content and fiber matrix adhesion being the most relevant, on guided wave propagation were examined, to allow for quality assessment. Guided wave measurements were supported by destructive analysis. Also an apparatus containing one endless loop of CFRP tape was constructed and built to simulate inline testing of CFRP tapes, as it would be employed in a CFRP tape production environment or at a CFRP tape processing facility. The influences of tape

Fabrication and mechanical testing of fibre reinforced thermoplastic composite tubes

International Nuclear Information System (INIS)

Tufail, M.

2005-01-01

Polymer based composites are produced using less expensive moulds and quick fabrication techniques. The overall processing cost for such materials is much lesser than metallic materials. Usually monolithic parts are produced out of composite materials which further decreases the processing time needed for joining sub- , assemblies as in the case of metallic parts. Any defects encountered due to sub-assemblies are also eliminated. Thermoset based composites have been used for long time to produce parts for automotive, aerospace, marine, and sports industries. The properties thus obtained by using thermoset as matrix are very well in comparison with metals but certain draw backs a.e there with this kind of matrix. Thermoset based composites are processed in untidy environment and once the object is produced can not be reshaped. In contrary to that thermoplastic materials are processed in a clean environment and the material can be recycled. The component once produced can easily be reshaped if required as no chemical reaction does take place during the process. Although the high melt viscosity of thermoplastic has limited its application as due to its high viscosity, its processing would be very difficult. Various methods have been developed to resolve this issue. In this study, a commingled material has been used to produce thermoplastic based composite tubes. The method developed for making such tubes is defined along with the method adopted to measure some of the mechanical properties of these tubes. (author)

Design of a rotary dielectric elastomer actuator using a topology optimization method based on pairs of curves

Science.gov (United States)

Wang, Nianfeng; Guo, Hao; Chen, Bicheng; Cui, Chaoyu; Zhang, Xianmin

2018-05-01

Dielectric elastomers (DE), known as electromechanical transducers, have been widely used in the field of sensors, generators, actuators and energy harvesting for decades. A large number of DE actuators including bending actuators, linear actuators and rotational actuators have been designed utilizing an experience design method. This paper proposes a new method for the design of DE actuators by using a topology optimization method based on pairs of curves. First, theoretical modeling and optimization design are discussed, after which a rotary dielectric elastomer actuator has been designed using this optimization method. Finally, experiments and comparisons between several DE actuators have been made to verify the optimized result.

Therapeutic plasma exchange: an effective treatment in ethylene dibromide poisoning cases.

Science.gov (United States)

Pahwa, Naresh; Bharani, Rajesh; Jain, Manish; Argal, Suarabh; Soni, Harish; Kosta, Susmit; Kumar, Ravindra

2013-10-01

Ethylene dibromide (EDB) poisoning is very common in Central India and has fatal outcome. EDB is highly protein bound and, therefore, it is suggested that therapeutic plasma exchange (TPE) may be useful in removing drug from body shortly after ingestion before EDB metabolizes and causes severe end organ damage. The aim of our study is to find the effect of time of start of TPE on survival outcome of EDB poisoning cases. Fifty-eight cases of EDB poisoning were reviewed from 2007 to 2012 in Department of critical care medicine in tertiary care hospitals at Indore. Five patients were discharged against medical advice and lost to follow up. TPE was done in 47 patients as early as possible and irrespective of appearance of clinical symptoms. TPE was not performed in six cases as they were hypotensive at admission. The patients with EDB poisoning were 15-45 yrs old with 3:2 male to female ratio. Out of 47 who received TPE, 39 patients survived. TPE had started within 24 h of ingestions of EDB in 36 out of 39 survived patients. Survival outcome was nine times higher in patients who received TPE within 24 h than after 24 h of ingestion. Survival rate was increased to 100% in patients where TPE was done within 12 h of ingestion of EDB. Early TPE help to remove plasma protein bound toxin with significant mortality reduction. However, delay in start of TPE after ingestion of poison has significant poor survival outcome. Copyright © 2013 Wiley Periodicals, Inc.

The Effects of Aluminium Hydroxide and Magnesium Hydroxide on the Mechanical Properties of Thermoplastic Polyurethane Materials

Directory of Open Access Journals (Sweden)

Erkin Akdoğan

2015-12-01

Full Text Available Thermoplastic polyurethane materials are widely used in automotive, clothing, electrical and electronics, medical, construction, machine industry due to excellent physical and chemical properties. Thermoplastic polyurethane materials combustion and resistance to high temperature characteristics are poor. Additives and fillers are added into the polyurethane matrix to improve those properties. Particularly adding these agents as a flame retardant are affect mechanical properties of polyurethane materials. Therefore, it is important to determinate the mechanical properties of these materials. In this study, 5% by weight of the thermoplastic polyurethane material, aluminium tri hydroxide (ATH, (Al2O3 3H2O and magnesium hydroxide (MgOH, (Mg(OH2 were added. Ammonium polyphosphate (APP as an intumescent flame retardant with inorganic flame retardants were added to increase the flame resistance of produced composite structure. Tensile test, tear test, hardness and Izod impact tests were made and compared of those produced composites. As a result of experiments the addition of ATH has lowered the tensile strength and tear strength contrast to this the addition of MgOH has improved those properties. Hardness and Izod impact test results were showed that both of the additives have no negative effect.

Production and 3D printing processing of bio-based thermoplastic filament

OpenAIRE

Gkartzou, Eleni; Koumoulos, Elias P.; Charitidis, Costas A.

2017-01-01

In this work, an extrusion-based 3D printing technique was employed for processing of biobased blends of Poly(Lactic Acid) (PLA) with low-cost kraft lignin. In Fused Filament Fabrication (FFF) 3D printing process, objects are built in a layer-by-layer fashion by melting, extruding and selectively depositing thermoplastic fibers on a platform. These fibers are used as building blocks for more complex structures with defined microarchitecture, in an automated, cost-effective process, with minim...

Dielectric silicone elastomers with mixed ceramic nanoparticles

International Nuclear Information System (INIS)

Stiubianu, George; Bele, Adrian; Cazacu, Maria; Racles, Carmen; Vlad, Stelian; Ignat, Mircea

2015-01-01

Highlights: • Composite ceramics nanoparticles (MCN) with zirconium dioxide and lead zirconate. • Dielectric elastomer films wDith PDMS matrix and MCN as dielectric filler. • Hydrophobic character—water resistant and good flexibility specific to siloxanes. • Increased value of dielectric constant with the content of MCN in dielectric films. • Increased energy output from uniaxial deformation of the dielectric elastomer films. - Abstract: A ceramic material consisting in a zirconium dioxide-lead zirconate mixture has been obtained by precipitation method, its composition being proved by wide angle X-ray powder diffraction and energy-dispersive X-ray spectroscopy. The average diameter of the ceramic particles ranged between 50 and 100 nm, as revealed by transmission electron microscopy images. These were surface treated and used as filler for a high molecular mass polydimethylsiloxane-α,ω-diol (Mn = 450,000) prepared in laboratory, the resulted composites being further processed as films and crosslinked. A condensation procedure, unusual for polydimethylsiloxane having such high molecular mass, with a trifunctional silane was approached for the crosslinking. The effect of filler content on electrical and mechanical properties of the resulted materials was studied and it was found that the dielectric permittivity of nanocomposites increased in line with the concentration of ceramic nanoparticles

Dielectric silicone elastomers with mixed ceramic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Stiubianu, George, E-mail: george.stiubianu@icmpp.ro [“Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi 700487 (Romania); Bele, Adrian; Cazacu, Maria; Racles, Carmen; Vlad, Stelian [“Petru Poni” Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi 700487 (Romania); Ignat, Mircea [National R& D Institute for Electrical Engineering ICPE-CA Bucharest, Splaiul Unirii 313, District 3, Bucharest 030138 (Romania)

2015-11-15

Highlights: • Composite ceramics nanoparticles (MCN) with zirconium dioxide and lead zirconate. • Dielectric elastomer films wDith PDMS matrix and MCN as dielectric filler. • Hydrophobic character—water resistant and good flexibility specific to siloxanes. • Increased value of dielectric constant with the content of MCN in dielectric films. • Increased energy output from uniaxial deformation of the dielectric elastomer films. - Abstract: A ceramic material consisting in a zirconium dioxide-lead zirconate mixture has been obtained by precipitation method, its composition being proved by wide angle X-ray powder diffraction and energy-dispersive X-ray spectroscopy. The average diameter of the ceramic particles ranged between 50 and 100 nm, as revealed by transmission electron microscopy images. These were surface treated and used as filler for a high molecular mass polydimethylsiloxane-α,ω-diol (Mn = 450,000) prepared in laboratory, the resulted composites being further processed as films and crosslinked. A condensation procedure, unusual for polydimethylsiloxane having such high molecular mass, with a trifunctional silane was approached for the crosslinking. The effect of filler content on electrical and mechanical properties of the resulted materials was studied and it was found that the dielectric permittivity of nanocomposites increased in line with the concentration of ceramic nanoparticles.

Liquid crystal elastomer coatings with programmed response of surface profile

NARCIS (Netherlands)

Babakhanova, G.; Turiv, T.; Guo, Y.; Hendrikx, M.; Wei, Q.H.; Schenning, A.P.H.J.; Broer, D.J.; Lavrentovich, O.D.

2018-01-01

Stimuli-responsive liquid crystal elastomers with molecular orientation coupled to rubber-like elasticity show a great potential as elements in soft robotics, sensing, and transport systems. The orientational order defines their mechanical response to external stimuli, such as thermally activated

Resonant wave energy harvester based on dielectric elastomer generator

Science.gov (United States)

Moretti, Giacomo; Pietro Rosati Papini, Gastone; Righi, Michele; Forehand, David; Ingram, David; Vertechy, Rocco; Fontana, Marco

2018-03-01

Dielectric elastomer generators (DEGs) are a class of capacitive solid-state devices that employ highly stretchable dielectrics and conductors to convert mechanical energy into high-voltage direct-current electricity. Their promising performance in terms of convertible energy and power density has been mostly proven in quasi-static experimental tests with prescribed deformation. However, the assessment of their ability in harvesting energy from a dynamic oscillating source of mechanical energy is crucial to demonstrate their effectiveness in practical applications. This paper reports a first demonstration of a DEG system that is able to convert the oscillating energy carried by water waves into electricity. A DEG prototype is built using a commercial polyacrylate film (VHB 4905 by 3M) and an experimental campaign is conducted in a wave-flume facility, i.e. an artificial basin that makes it possible to generate programmed small-scale waves at different frequencies and amplitudes. In resonant conditions, the designed system demonstrates the delivery of a maximum of 0.87 W of electrical power output and 0.64 J energy generated per cycle, with corresponding densities per unit mass of dielectric elastomer of 197 W kg-1 and 145 J kg-1. Additionally, a notable maximum fraction of 18% of the input wave energy is converted into electricity. The presented results provide a promising demonstration of the operation and effectiveness of ocean wave energy converters based on elastic capacitive generators.

fs- and ns-laser processing of polydimethylsiloxane (PDMS) elastomer: Comparative study

Energy Technology Data Exchange (ETDEWEB)

Stankova, N.E., E-mail: nestankova@yahoo.com [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Shose, Sofia 1784 (Bulgaria); Atanasov, P.A.; Nedyalkov, N.N.; Stoyanchov, T.R. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsarigradsko Shose, Sofia 1784 (Bulgaria); Kolev, K.N.; Valova, E.I.; Georgieva, J.S.; Armyanov, St.A. [Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria); Amoruso, S.; Wang, X.; Bruzzese, R. [CNR-SPIN, Dipartimento di Scienze Fisiche, Universita degli Studi di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Grochowska, K.; Śliwiński, G. [Photophysics Department, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St., 80-231 Gdańsk (Poland); Baert, K.; Hubin, A. [Vrije Universiteit Brussels, Faculty of Engineering, Research group, SURF “Electrochemical and Surface Engineering” (Belgium); Delplancke, M.P.; Dille, J. [Université Libre de Bruxelles, Materials Engineering, Characterization, Synthesis and Recycling (Service 4MAT), Faculté des Sciences Appliquées, 1050 Brussels (Belgium)

2015-05-01

Highlights: • fs- and ns-laser (266 and 532 nm) processing of PDMS-elastomer, in air, is studied. • High definition tracks (on the PDMS-elastomer surface) for electrodes are produced. • Selective Pt or Ni metallization of the tracks is produced via electroless plating. • Irradiated and metallized tracks are characterized by μ-Raman spectrometry and SEM. • DC resistance of Pt and Ni tracks is always between 0.5 and 15 Ω/mm. - Abstract: Medical grade polydimethylsiloxane (PDMS) elastomer is a widely used biomaterial as encapsulation and/or as substrate insulator carrier for long term neural implants because of its remarkable properties. Femtosecond (λ = 263 and 527 nm) and nanosecond (266 and 532 nm) laser processing of PDMS-elastomer surface, in air, is investigated. The influence of different processing parameters, including laser wavelength, pulse duration, fluence, scanning speed and overlapping of the subsequent pulses, on the surface activation and the surface morphology are studied. High definition tracks and electrodes are produced. Remarkable alterations of the chemical composition and structural morphology of the ablated traces are observed in comparison with the native material. Raman spectra illustrate well-defined dependence of the chemical composition on the laser fluence, pulse duration, number of pulses and wavelength. An extra peak about ∼512–518 cm{sup −1}, assigned to crystalline silicon, is observed after ns- or visible fs-laser processing of the surface. In all cases, the intensities of Si−O−Si symmetric stretching at 488 cm{sup −1}, Si−CH{sub 3} symmetric rocking at 685 cm{sup −1}, Si−C symmetric stretching at 709 cm{sup −1}, CH{sub 3} asymmetric rocking + Si−C asymmetric stretching at 787 cm{sup −1}, and CH{sub 3} symmetric rocking at 859 cm{sup −1}, modes strongly decrease. The laser processed areas are also analyzed by SEM and optical microscopy. Selective Pt or Ni metallization of the laser processed