Effect of Solution Aging on Mechanical Properties of Poly(ethylene terephthalate)

Abstract

Polyethylene terephthalate (PET) is a crystalline polymer with a high melting temperature (Tm) and glass transition temperature (Tg). Because of its good barrier properties, it is widely used in food, chemical, pharmaceutical packaging, electronics and many other fields. But due to the large number of ester bonds in the main chain of PET macromolecules, it is easily degraded by strong acids, bases and water vapor, and lead to the decrease of physical and mechanical properties. In this paper, PET was immersed in three different solutions (water, sulfuric acid, sodium chloride) to accelerate the aging. Combining with the mechanical properties test, the change of mechanical properties of PET before and after solution aging was studied to provide reference for improving the aging properties of PET. The results show that the tensile strength of PET increased by 12.7MPa, the flexural strength increased by 18.8MPa, the elongation at break decreased from 290% to zero with the aging time of solution, and the change of notched impact strength and hardness was not significant.