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Showing 1 to 15 of 15 for “"semi-crystalline polymer"”.
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Influence of processing on the structure and properties of semi-crystalline polymer systems : 1) biodegradable starch/poly(ethylene-vinyl alcohol) blends and 2) polyolefinic thermoplastics
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1995.
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Understanding of the mechanical response of semicrystalline polymers based on the block-like substructure of crystalline lamellae
… of a range of PE and sPP samples as models of semi-crystalline polymer systems under tensile deformation. Splitting the total tensile deformation into elastic and plastic parts shows four characteristic points (A,B,C and D) from the true stress-true strain curves, where the differential …
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Process/Structure/Property Relationships of Semi-Crystalline Polymers in Material Extrusion Additive Manufacturing
… in most typical MEX processes, only amorphous polymers are being used as feedstock material owing to their smaller dimensional shrinkage during cooling and well-stablished process/structure/property (P/S/P) relationship. Semi-crystalline polymers, with their crystalline nature, possess unique …
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Hot-melt mixing of partially miscible active pharmaceutical ingredient-polymer mixtures
… to a great extent by converting drugs from crystalline to amorphous form. HME can be carried out at two process temperature regimes: one where T_{process} > T_m of the drug and the T_g of the polymer (or the T_m for the case of semi-crystalline polymers); the other at T_m > T_{process} > T_g …
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Crystallization Behavior, Tailored Microstructure, and Structure-Property Relationships of Poly(Ether Ketone Ketone) and Polyolefins
… and chemical properties of fast crystallizing polymers. The primary objectives were to 1) utilize advanced methodologies to accurately determine the fundamental thermodynamic value of equilibrium melting temperature (Tmo) for the semi-crystalline polymer poly(ether ketone ketone) (PEKK), 2) …
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Plasticity and impact test studies on thermoplastic materials, finite element analysis and experimental correlation
… T45 from Bayer Material Science, as an amorphous polymer and a Polypropylene (PP) copolymer, BE677AI from Borealis, as a semi-crystalline polymer. The uniaxial tensile behavior of both materials was used to generate material data input for the simulation software. Due to post yield uncertainties …
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Modeling Heat Transfer and Densification during Laser Sintering of Viscoelastic Polymers
… relationships for LS of viscoelastic polymers. A one-dimensional closed-form analytical solution for heating of a semi-infinite body, with a convective boundary condition, by a moving surface heat flux was developed. This solution approximates the shape of the Gaussian energy …
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Process and Material Modifications to Enable New Material for Material Extrusion Additive Manufacturing
… in the FFF process, post-process, and polymer composition. This research was conducted at two opposing ends of the FFF-processing temperature: low processing temperature (<100 °C) for pharmaceutical applications and high processing temperatures (>300 °C) for high-performance structural …
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Shape Memory Assisted Self Healing (Smash) Polymeric and Composite Systems
… memory (SM) effect to aid self healing (SH) polymeric systems that are able to simultaneously close and re-bond cracks with a single thermal stimulus. This new concept is termed shape memory assisted self healing (SMASH). Additionally, a new type of shape memory termed reversible plasticity …
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Effect of Laser Induced Crystallinity Modification on Degradation and Drug Release of Biodegradable Polymer
Biodegradable polymers such as poly(L-lactic acid) (PLLA) are promising in drug delivery applications. In biodegradable polymer-based drug delivery systems, drugs are released at a rate determined by polymer degradation. Polymer degradation exhibits an undesirable induction period, during which a …
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Production of Polyhydroxyalkanoates by Pseudomonas mendocina using vegetable oils and their characterisation
… fermentation profiles showed better growth and polymer production as compared to conditions when sodium octanoate was used as the carbon source. In addition, comparison of PHA accumulation at shaken flask and fermenter level confirmed the higher PHA yield at shaken flask level production. The …
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Biodegradable Thermoplastic Elastomers and Smart Composites
… literature of relevant background information on polymers, biomaterials, and previous biodegradable elastomers and responsive elastomeric systems. </p> <p>The first biodegradable elastomer developed and investigated, as presented in Chapter 2, is a novel thermoplastic polyurethane that has a …
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A model treating tensile deformation of semi-crystalline polymers
Semi-crystalline polymeric solids are usually in a state being built up of crystallites and an amorphous phase. A complex structure changing occurs in the polymer materials during the extension process. Uniaxial stretching of a semi-crystalline polymer sample causes the initial spherulitic …
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Synthetic Design of Multiphase Systems for Advanced Polymeric Materials
… to the amorphous regions of the semi-crystalline parent homopolymer and generates a copolymer with a blocky microstructure. Solution-state functionalization yields random copolymers which provide matched sets to the blocky analogs for fundamental investigations into the effects of …
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Processing Extrudable Sheets using Decoloured Bloodmeal
… material, with poly (lactic acid) (PLA), a semi-crystalline polymer, and subsequently processing the blend into a sheet using extrusion. Free radical grafting was used to graft itaconic anhydride onto PLA to create reactive side groups. Blends of DBT and PLA compatibilized with itaconic …