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Showing 1 to 20 of 109 for “"Polyesters"”.
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A model for casting polyesters
… of the curing reaction of thermoset polyesters were accomplished, and a mathematical curing model was proposed for the casting operation of these plastics. Temperature distribution through the thickness of the polymer mass was obtained by monitoring thermocouples placed at known …
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Melting point depression in biodegradable polyesters
Investigation into the crystallisation kinetics and melting point depression of poly(L-lactideco-meso-lactide) with approximately 3.3% D-lactide content (PLA 3051D) was undertaken. The rate of crystallisation was too slow for a crystallisation exotherm to be detected by the DSC, therefore hot-stage …
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Copolymerisation of polyesters using reactive extrusion
The high recycling rate of post-consumer polyethylene terephthalate (PET) through cost-effective mechanical process faces challenges such as undesirable colour waste and material degradation after repeated cycles, which limit its long-term effectiveness. Meanwhile, bioplastics such as polybutylene …
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Determination of orientation in aromatic polyesters
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1998.
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Structure-Property Relationships of Alicyclic Polyesters
Polyesters are an important class of polymers in many applications ranging from common-use objects—such as packaging containers, clothing, and upholstery—to more advanced applications, such as lightweight strength materials in construction, electronics, and automotive parts. Poly(ethylene …
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Reactive modification of polyesters and their blends
… to investigate the chemical modification of polyesters by reactive processing a low molecular weight (MW) unsaturated polyester (UP) and a higher MW saturated polyester, polyethylene terephthalate (PET), alone or blended with polypropylene (PP) were melt processed in a batch mixer and …
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Synthesis and Characterization of Functional Biodegradable Polyesters
The ring opening polymerization of D,L-lactide (DLLA) using multifunctional hydroxyl-terminated initiators and catalyst/coinitiator systems based on Sn(Oct)2 afforded the preparation of star-shaped, poly(D,L-lactide)s (PDLLA)s of controlled molar mass, narrow molar mass distributions, and …
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Mechanistic Studies of the Enzymatic Synthesis of Polyesters
… low dispersity and high molecular weight polyesters are formed due to the limited solubility of the polyester in the diol, only limited transesterification occurring at the ends of the chain. Molecular modelling was used to map the surface hydrophobicity around the enzyme active site in an …
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Design of Functional Polyesters for Electronic and Biological Applications
… and novel monomers enabled the synthesis of polyesters for electronic and biological applications. Inspiration from nature and a passion for environmental preservation instigated an emphasis on the incorporation of renewable resources into polymeric materials. Critical analysis of current …
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The synthesis of novel biodegradable polyesters and copolyesters from anhydrosulfites
… of anhydrosulfites with -caprolactone. The polyesters and copolyesters synthesised are of considerable interest in medical applications and also for use as environmental friendly packaging. A range of anhydrosulfites were prepared according to an established method. Aliphatic anhydrosulfites …
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Synthesis and Characterization of Multicomponent Polyesters via Step-growth Polymerization
Poly(ethylene terephthalate) (PET) is an important commercial polyester and widely used as fibers, packagings, containers and engineering materials. It is believed that the incorporation of a low level of ionic groups into PETs dramatically improves the mechanical performance and compatibility with …
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Hyperbranched Aromatic Polyesters and Their Application in Blends of Linear Polyamides
In the last two decades, hyperbranched (hb) polymers have drawn much attention and obtained intensive research activities both from industry and academia. They are known to have unique and interesting properties which derive from their three dimensional structure and the large number of functional …
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Synthesis and Structure-Property Relationships of Polyesters Containing Rigid Aromatic Structures
Polyesters are an attractive class of polymer that can be readily modified with a wide range of different comonomers, during polymerization or with melt blending, to achieve a wide variety of physical properties. This research primarily focuses on polyesters that incorporate rigid aromatic …
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Hyperbranched polyesters for polyurethane coatings: their preparation, structure and crosslinking with polyisocyanates
In this work, hyperbranched aromatic polyesters-polyphenols based on 4,4-bis(4’ hydroxy¬phenyl)pentanoic acid (BHPPA) were prepared and, according to the authors knowledge, for the first time tested as precursors for polyurethane bulk resins and coatings. Comparison of poly-BHPPA with competing …
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Characterization and control of surface properties of degradable polyesters for cell culture
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1996.
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