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  • Open Access

    ARTICLE

    Polyols Based on Poly(ethylene terephthalate) and Tall Oil: Perspectives for Synthesis and Production of Rigid Polyurethane Foams

    A. Ivdre1*, G.D. Soto2, U. Cabulis1

    Journal of Renewable Materials, Vol.4, No.4, pp. 285-293, 2016, DOI:10.7569/JRM.2016.634122

    Abstract This study presents the synthesis of novel polyols made from tall oil (TO) and poly(ethylene terephthalate) (PET) with different TO/PET molar ratios. Rigid polyurethane foams based on these synthesized polyols were obtained and characterized to evaluate polyols’ suitability for the development of light materials with insulating properties. The effect of TO/PET molar ratios on the physical, morphological and mechanical properties of the obtained foams, as well as their thermal insulation characteristics, were evaluated. Increasing amounts of PET in polyurethane foams resulted in higher compression strength and closed cell content, while water absorption was not affected. Results indicated that certain TO/PET… More >

  • Open Access

    ARTICLE

    A Nonlinear Viscoelastic Finite Element Model of Polyethylene

    P.C. Chen∗,†, C.W. Colwell, D.D. D’Lima†,‡

    Molecular & Cellular Biomechanics, Vol.8, No.2, pp. 135-148, 2011, DOI:10.3970/mcb.2011.008.135

    Abstract A nonlinear viscoelastic finite element model of ultra-high molecular weight polyethylene (UHMWPE) was developed in this study. Eight cylindrical specimens were machined from ram extruded UHMWPE bar stock (GUR 1020) and tested under constant compression at 7% strain for 100 sec. The stress strain data during the initial ramp up to 7% strain was utilized to model the "instantaneous" stress-strain response using a Mooney-Rivlin material model. The viscoelastic behavior was modeled using the time-dependent relaxation in stress seen after the initial maximum stress was achieved using a stored energy formulation. A cylindrical model of similar dimensions was created using a… More >

  • Open Access

    ARTICLE

    Computational Characterization and Evaluation of Deformation Behavior of Spherulite of High Density Polyethylene in Mesoscale Domain

    Y. Tomita 1, M. Uchida 1

    CMES-Computer Modeling in Engineering & Sciences, Vol.10, No.3, pp. 239-248, 2005, DOI:10.3970/cmes.2005.010.239

    Abstract In this study, we clarified the micro- to mesoscopic deformation behavior of a semicrystalline polymer by employing a large-deformation finite element homogenization method. The crystalline plasticity theory with a penalty method for the inextensibility of the chain direction and the nonaffine molecular chain network theory were applied for the representation of the deformation behavior of the crystalline and amorphous phases, respectively, in the composite microstructure of the semicrystalline polymer. The 3D structure of lamellae in the spherulite of high-density polyethylene was modeled, and the tensile and compressive deformation behaviors were investigated. A series of computational simulations clarified the difference in… More >

  • Open Access

    ARTICLE

    A Experimental Study on the Rhelogical and Mechanical Properties of Blends of Polyethylene and Modified Oil Shale Ash (MOSA)

    Y.H. Liu1, X.X. Xue2, J.M.Shen1

    FDMP-Fluid Dynamics & Materials Processing, Vol.11, No.2, pp. 197-204, 2015, DOI:10.3970/fdmp.2015.011.195

    Abstract Blends of Polyethylene (PE) and modified-oil shale ash (MOSA) with different fractions of MOSA were prepared by the melting blend method. The effects of MOSA content on the rheological and mechanical properties of the blend were properly assessed via direct experimental analysis (more precisely, all rheological measurements were performed using a laboratory-scale XSS-300 torque rheometer with single screw extruder; the temperatures were maintained at 170°C, 180°C and 190°C under continuous extrusion). The prepared samples were observed to display a shear-thinning behaviour. Moreover, with increasing the MOSA content, we found the yield strength of the blends to increase, while its elongation… More >

  • Open Access

    ARTICLE

    Molecular Design of the Solid Copolymer Electrolyte- Poly(styrene-b-ethylene oxide) for Lithium Ion Batteries

    Cheng-Hung San1, Che-Wun Hong1,2

    CMC-Computers, Materials & Continua, Vol.23, No.2, pp. 101-118, 2011, DOI:10.3970/cmc.2011.023.101

    Abstract Poly(ethylene oxide) (PEO) is a commonly used electrolytic polymer in lithium ion batteries because of its high viscosity which allows fabricating thin layers. However, its inherent low ionic conductivity must be enhanced by the addition of highly conductive salt additives. Also its weak mechanical strength needs a complementary block, such as poly(styrene) (PS), to strengthen the electrolytic membrane during charging/discharging processes. PS is a strong material to complement the PEO and to create a reinforced copolymer electrolyte termed as the poly(styrene-b-ethylene oxide) (PS-PEO). In this work, molecular dynamics simulations are employed to study the effects of doping the PS constituents… More >

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