AbstractThe texture of a polymer (on fiber) is effectively developed by heat and stress. In this article, the chief material studied is acrylics, usually polyacrylonitile copolymer (PAC fiber) produced by Jingshan Jinglun Fiber Production Plant. In industry, the Jinglun acrylic fiber is heat treated, using saturated steam, at a temperature of 120–130°C to enhance its loop strength, reduce shrinkage, and stabilize crimp. At 140°C, the fiber becomes tacky and its good textile properties seem to deteriorate. At 150–160°C, the texture of the fiber seems to be deeply modified. Tested by differential scanning calorimetry (DSC) with the fiber immersed in a swelling agent (usually termed swelling DSC, abbreviated as SDSC), in addition to the entanglement peaks situated on the latter part of the thermogram of the Jinglun fiber, a new endothermic peak before the crystalline peak (actually, paracrystalline in the case of acrylic fiber) was discovered. The elastic recovery properties of the treated fiber under partially swelling conditions were improved. This seems to indicate that this preparacrystalline peak might also be concerned with entangl
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