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Showing 1 to 20 of 89 for “"Semicrystalline"”.
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Shear induced morphology of semicrystalline block copolymers
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994.
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The synthesis and characterization of semicrystalline polyimides
Polyimides derived from 2,2-bis[4-(4-aminophenoxy)phenyl]-hexafluoropropane (BDAF) and pyromellitic dianhydride (PMDA) displayed a glass transition temperature (Tg) at 306°C and a melting point (Tm) near 470°C as measured by differential scanning calorimetry (DSC) with a heating rate of 10°C/min. …
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Lifetime Estimation for Ductile Failure in Semicrystalline Polymer Pipes
The aim of this study is to develop a combined experimental and analytical framework for accelerated lifetime estimates of semi-crystalline plastic pipes which is sensitive to changes in structure, orientation, and morphology introduced by processing conditions. To accomplish this task, …
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Relationship between the micromorphology and mechanical properties of semicrystalline polypropylene
The objective of this research project was to carry out the investigation of the relationship between processing conditions, micromorphology and mechanical properties of isotactic polypropylene homopolymer using conventional and shear controlled orientation injection moulding (SCORIM) techniques by …
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X-ray scattering and molecular modeling of novel semicrystalline polyimides
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994.
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Altering the fiber-matrix interphase in semicrystalline polymer matrix composites
When many semicrystalline polymers are used as matrix materials in composites, a morphology known as the transcrystalline region is formed on the surface of the reinforcing material. This region introduces a new crystalline structure to the system that is different from that of the bulk matrix …
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Numerical stimulation of stress-induced crystallization of injection molded semicrystalline thermoplastics
Injection molded semicrystalline plastic products exhibit variable morphology along their thickness directions. The processing conditions have a significant effect on the crystallinity distribution in the final parts. However, because of the lack of sound theoretical models for stress-induced …
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Micromechanical modeling of the toughening mechanisms in particle-modified semicrystalline polymers
It is now well appreciated that a number of sernicrystalline polymers can be effectively toughened by the addition of a well-dispersed secondary phase. In particular, when the average interparticle matrix ligament thickness, A, of the blend is reduced below a critical length parameter, Ac, dramatic …
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Investigations of the Processing-Structure-Property Relationships of Selected Semicrystalline Polymers
… (MEAUS) utilized to produce semicrystalline polymeric microporous membranes. The two semicrystalline polymers studied were selected based on a set-of-prerequisites proposed for the formation of highly porous membranes via the method in question. The prerequisites included …
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Morphology-Property Relationships in Semicrystalline Aerogels of Poly(ether ether ketone)
The phase diagrams for the thermoreversible gelation of poly(ether ether ketone) (PEEK) in dichloroacetic acid (DCA) and 4-chlorophenol (4CP) were constructed over broad temperature and concentration ranges, revealing that PEEK is capable of dissolving and forming gels in DCA and 4CP up to a weight …
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Chemical and Physical Modifications of Semicrystalline Gels to Achieve Controlled Heterogeneity
… In this work, the functionalization of semicrystalline gels of poly(ether ether ketone) (PEEK) is explored as a novel post-polymerization method to prepared blocky copolymers, and the effect of copolymer architecture on membrane physical properties, structure, and performance is …
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The synthesis, stabilization and sintering of high performance semicrystalline polymeric powders
… with 4,4'-difluorobenzophenone to afford a semicrystalline, soluble PEEK derivative. Acid catalyzed hydrolysis of these derivatives to insoluble PEEK can be used to generate submicron particles. A high performance stabilizer, which was used for suspending PEEK particles in water, has also …
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Field induced orientation of semicrystalline and non-crystallne block copolymer microdomain patterns
… microdomains along the flow direction in a semicrystalline block copolymer. Subsequent crystallization of the crystalline block is significantly influenced by the pre-existing oriented amorphous cylindrical microdomains. The orientation of crystalline lamellae is achieved parallel to the …
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Crystallization and structure-property investigations of semicrystalline poly(arylene ether) based polymers
… of a series of high performance polyimides. Semicrystalline polyimides based on an all para-linked diamine, 1,4-bis(4-aminophenoxy)benzene (TPEQ diamine) and oxydiphthalic dianhydride (ODPA), endcapped with phthalic anhydride (PA) (T<sub>g</sub> = ca. 230 °C, T<sub>m</sub> = ca. 420 °C), and …
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Crystallization and melting behavior of an aromatic semicrystalline polyimide, LaRC CPI-2
Research is presented on the crystallization and melting behavior of an aromatic semi crystalline polyimide known as LaRC CPI - 2 (Langley Research Center Crystalline rolyimide - second generation). This aromatic polyimide, a structural variant of the well known LaRC CPI, is synthesized froml …
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Development of Thermoplastic Elastomers with Improved Elastic Properties Based on Semicrystalline Block Copolymers
… comprises multiblock copoly(ether ester)s with semicrystalline hard segments and triblock copolymer soft segments. The second class of TPEs are systems based on ABA and ABC triblock copolymers with two glassy and one or two semicrystalline end blocks, respectively. The used strategy for …
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Material Extrusion based Additive Manufacturing of Semicrystalline Polymers: Correlating Rheology with Print Properties
… Current approaches towards MatEx of semicrystalline thermoplastics are in their nascent stage with fiber reinforcements being one of the most common techniques. MatEx of commodity semicrystalline thermoplastics has been investigated but most of the current methods are extremely …
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Crystallization, Morphology, Thermal Stability and Adhesive Properties of Novel High Performance Semicrystalline Polyimides
… morphology and thermal stability of two novel semicrystalline polyimides based on the same diamine, 1,3-bis (4-aminophenoxy) benzene (TPER), but two different dianhydrides, 3,3',4',4'-biphenyltetracarboxylic dianhydride (BPDA) and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA). …
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Charge and Thermoelectric Transport in Semicrystalline Conjugated Polymers and Single-Walled Carbon Nanotube Networks
… it is demonstrated that charge transport in semicrystalline high-mobility copolymers is incompatible with disorder-based transport models that were developed for preceding, more disordered polymers. Instead the charge density and temperature dependence of the field-effect mobility and gated …
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Thermoelectric Properties and Transport of Semicrystalline Conjugated Polymer and Single-Wall Carbon Nanotube Composites
Research into carbon nanotubes (CNT):polymer composites for thermoelectric applications have greatly expanded in recent years, aiming to combine the high power factor of CNT networks and the low thermal conductivity of polymer matrix. Many attempts have been made on achieving the …
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