HEAT TREATMENT METHOD FOR HIGH CRYSTALLINE OF POLYVINYLIDEN FLUORIDE

摘要

PURPOSE: A heat treatment method for high crystallinity PVDF is provided to improve crystallinity reduced after heat treatment by the change of cooling temperature and to manufacture a polymer separation film with strong chemical resistance. CONSTITUTION: A heat treatment method for high crystallinity PVDF comprises a step of sintering pure PVDF at a melting temperature or higher for a predetermined time (S110); a step of cooling several times the PVDF at temperature from the melting temperature to the crystallization temperature to control the crystallization time of the PVDF (S120); a step of observing the gradient of crystallinity according to the maintaining time by changing the maintaining time varying with the cooling temperature (S130). The sintering step is conducted for 5-15 minutes at 200-220°C. [Reference numerals] (AA) Start; (BB) End; (S110) Step of sintering pure PVDF; (S120) Step of controlling the crystallization time of the PVDF; (S130) Step of observing the gradient of crystallinity; (S140) Step of obtaining PVDF crystallinity value