A family of synthetic elastic fibers, designated spandex fibers, has been developed, providing new degrees of sheerness and effective "power" in elastic fabrics. These fibers have segmented polyurethane structures. They are durable, they are white and accept dye readily, and they can be set by heat. The development of these fibers has led to new textile technology and to new uses for elastic fabrics.
The copolymerization of itaconic anhydride and styrene has been studied and the r1‐r2 values determined. In benzene r1 = 0.78, r2 = 0.015; in tetrahydrofuran r1 0.60, = r2, 0.10. One possible explanation of the definite positive deviation from constant values in the different solvents has been advanced; it is based on the fact that the copolymer precipitates from benzene as formed. In all cases the r1, r2 product is in the order of 0.01 to 0.06 and indicates that the copolymer is highly alternating in structure. Excellent agreement has been obtained between values of copolymer compositions by analysis and values predicted by copolymer theory based on the copolymer equation. Copolymers of molecular weights in the order of 50,000 to 150,000 (determined by light scattering) were prepared. The rate of copolymerization was about twenty times faster in benzene than in tetrahydrofuran.
A useful method, more rapid and more accurate than elemental analysis, has been developed to determine the composition of copolymers of itaconic anhydride and maleic anhydride with styrene. The method involves a high frequency titration of the sample. The method can also be used to detect traces of acidic impurities in polymers and in the identification of mixtures of similar acidic copolymers. Titration indicates that the acid segments in the copolymers of itaconic acid–styrene, maleic acid–styrene, and the homopolymer polyitaconic acid act as dibasic acids. The method appears to have a sensitivity that permits identification and approximate resolution of two carboxylate species in the same polymer.
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