Poly condensation definition

Let us consider the physical sense and definition of fractional exponent Vg. value in the given context. As it is known [84, 85], polycondensation process ceases in gelation point, for which the fractal dimension dj of a forming stmcture is equal to 2.50. This means, that fractal (macromolecular coil) fraction, not included in evolution (poly condensation) process, at gelation point reaches its maximum value V =1.0. From the said above it follows, that in the considered case at v =1.0 d=D =... 

A series of lyotropic poly(imide-amide)s were synthesised [39], in which an ordered unit comprising trimellitimide condensed with p-aminobenzoic acid andp-phenylene diamine (PPD) was copolymerised in varying ratios (0,50 and 80%) with a terephthalic acid/PPD polyamide. The MI predicts all three polymers to be LC, but lyotropic behaviour was observed in only the first one (Table 13). This is particularly surprising because incorporating increasing quantities of the known lyotropic and more linear TPA/PPD units would be expected to produce definite lyotropic behaviour. Similarly, a copoly(amide-imi-de) of 3,3 -dimethyl benzidene and 4-amino benzoic trimellitimide was predicted by the MI to possess a mesophase but none was detected. These apparent failures may be due to the fact that the polymers which did show lyotropic behav-... 

Poly(butylene terephthalate) is usually called PBT by analogy with PET, the well known fiber forming thermoplastic polyester. Like PET, PBT Is a linear condensation polymer based on tere-phthallc acid,, but Instead pf the ethylene glycol used in PET, PBT employs 1,4-butanedlol. ] The more definitive name, poly (tetramethylene terephthalate) or PTMT, never did catch on, perhaps an Indication of the power of three letter strings In the English alphabet. 

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