Homopolymers microstructural analysis

Other applications of FTIR in microstructural analysis of homopolymers include 1,4-diazophenylene - bridged Cu-phthalocyanine [63], isobornyl methacrylate [64], polypropylene [65, 66], polyaniline [67, 68], polycaprolactone [69], viscose fibres [70], Kevlar [71], polystyrene sulfonic acid [66, 72], syndiotactic polystyrene [73], isotactic polypropylene [66,74,75], polyurethane [76], PMMA [75, 77], poljmrethane ether [78], PE [79-80], fluorinated acrylates [81], rigid PU [82], N-(2-biphenyl)4-(2 phenylethynyljphthalamide [83], polyacrylic acid [84], polysodium styrene sulfonate [84], and polyacrylic acid [85]. 

Three diblock copolymers of cis-1,4 polyisoprene (IR) and 1,4-polybutadiene (BR) have been studied in dynamic mechanical experiments, transmission electron microscopy, and thermomechanical analysis. The block copolymers had molar ratios of 1/2, 1/1, and 2/1 for the isoprene and butadiene blocks. Homopolymers of polybutadiene and polyisoprene with various diene microstructures also were examined using similar experimental methods. Results indicate that in all three copolymers, the polybutadiene and polyisoprene blocks are essentially compatible whereas blends of homopolymers of similar molecular weights and microstructures were incompatible. 

Several polysilylene copolymers have also been examined by Si NMR. West and co-workers (3) report that phenylmethyldichlorosilane, when copolymerized with either dimethyldichlorosilane or methylhexyldichlorosil-ane, yields a copolymer with a blocklike structure. In contrast, we have observed that the copolymers of dimethyldichlorosilane with di-n-hexyldi-chlorosilane and n-propylmethyldichlorosilane with isopropylmethyldichlo-rosilane have random structures. These several examples indicate clearly that Si NMR spectra can provide a complete analysis of chain microstructure for the soluble polysilylene homopolymers and copolymers. 

The study of the macromolecular microstructure gives information on the stereochemical mechanism of polymerization. The NMR analysis of homopolymers and copolymers of selectively deuterated propylenes allowed the determination of the mechanism of addition to the double bond in the stereospecific polymerizations. The causes of the steric control may be also evidenced by micro-structural analysis on suitable macromolecules. 

Applications and examples of microscopy imaging and analysis to multicomponent polymers follow. The microstructure of semicrystalline multicomponent polymers can often be determined by polarized light microscopy of thin sections. A blend of two polyacetals, a homopolymer and a copolymer, is shown in the micrograph of a thin section (Fig. 5.68). The structure is rather interesting... 

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