Poly fusion parameters

An interesting comparison in the fusion parameters can be made between the aliphatic poly(urethanes) and the corresponding poly(amides) based on either 1,6 hexamethylene diamine, or hexamethylene diisocyanate each with similar dicar-... 

A different type of silicone polymer containing a ring in the chain, poly(tetra methyl-p-silphenylene siloxane), has amelting temperature of 160 °C, due in part to the aromatic ring in the backbone. There is, however, no indication that this polymer forms an anisotropic phase and the fusion parameters are normal ones.(169)... 

The crystallization of poly(ethylene terephthalate) at different temperatures after prior fusion at 294 C has been observed to follow the Avrami equation with the following parameters applying at the indicated temperatures ... 

A new class of hydrophilic polyamides, poly(tetrahydropyran-2,6-diylimino-carbonyl) 1 was prepared by the anionic polymerization of a bicyclic oxalactam (abbreviated as BOL, 2) 38-42). The resulting polyamide / has glass transition, fusion, and decomposition points at 130,260-285, and 315 °C, respectively, and its membrane can be obtained by casting from a polyBOL solution. The solubility parameter... 

Copolymerization. Vinyl chloride can be copolymerized with a variety of monomers. Vinyl acetate [9003-22-9], the most important commercial comonomer, is used to reduce crystallinity, which aids fusion and allows lower processing temperatures. Copolymers are used in flooring and coatings. This copolymer sometimes contains maleic acid or vinyl alcohol (hydrolyzed from the poly(vinyl acetate)) to improve the coating s adhesion to other materials, including metals. Copolymers with vinylidene chloride are used as barrier films and coatings. Copolymers of vinyl chloride with maleates or fumerates are used to raise heat deflection temperature. Copolymers of vinyl chloride with acrylic esters in latex form are used as film formers in paint, nonwoven fabric binders, adhesives, and coatings. Copolymers with olefins improve thermal stability and melt flow, but at some loss of heat-deflection temperature (100). Copolymerization parameters are listed in Table 5. 

In order to dissolve crystalline polymers, it is necessary to consider the Gibbs energy of fusion. This additional energy expenditure is not taken into account in the concept of the solubility parameter. Crystalline polymers therefore often dissolve only above their melting temperatures and in solvents with roughly the same solubility parameter. Unbranched, highly crystalline poly(ethylene) (62 = 8.0) only dissolves in decane (61 = 7.8) at temperatures close to the melting point of 135°C. 

Table 2.4. Parameters governing fusion of poly (ethylene oxide) ...

Table 3 Parameters Governing Fusion of Poly(ethylene oxide) 112 ...

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