During stretching, with the increase PTFE Tape of the stretching ratio, the transmittance of the raw material tape decreases, which is due to the fact that the spherulite structure of the polymer gradually changes into a microfiber structure and aligns during the stretching process, making the amorphous region It also becomes ordered, which increases the difficulty when the permeating agent passes through.
The stretching orientation has a great influence on the transmittance of the crystalline polymer, and its change is more obvious when the crystallinity is 10%-15%. At 40%-50%, the stretching orientation can almost no longer achieve biaxial stretching orientation, but the orientation process is dependent on the processing conditions, and the cooling rate, stress, etc. will affect the crystallization and the degree of crystallinity. and phase structure.
