Study on the Chain Entanglement of Polyvinyl Alcohol Fiber during the Dry-Jet Wet Spinning Process

摘要

The entanglement structure of polyvinyl alcohol (PVA) fiber during the dry-jet wet spinning process is studied in this article. The morphological changes of PVA fiber in swelling agent are observed under optical polarizing thermomicroscope, and the entanglement changes of PVA fiber during the spinning process are investigated using swelling DSC method. A specific mixture consisting of a good solvent (DMSO) and a poor solvent (EG) is used as the swelling agent for PVA. Results show that the entanglement structure of PVA fiber would disentangle after the crystalline phase is destroyed in the swelling agent during heating, and the entanglement structure of PVA fiber is greatly dependent on the spinning technological parameters such as spinning dope concentration, jet stretch ratio, extruding shear stress and draw ratio of the whole spinning process. When the spinning dope and spinning technological parameters are controlled properly, the entanglement structure in the PVA fiber can be greatly reduced and PVA fiber with a 17.5 cN/dtex tensile strength can be obtained.