Introduction to PP PET Alloy Research

Polypropylene (PP) is a thermoplastic synthetic resin with excellent properties, and is a colorless and translucent thermoplastic lightweight general-purpose plastic. It has chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties and good high wear-resistant processing properties. The main disadvantages of polypropylene are low-temperature brittleness and large shrinkage, poor colorability, and poor weather resistance, which limit its scope of use. In recent years, the use of polymerization modification, blending modification and both technologies have been used to prepare new engineered polypropylene materials.

For systems with poor PP/polymer compatibility, the polymer is functionalized to prepare a compatibilizer and blended into the blending system to prepare PP alloys to improve the compatibility of PP blends and improve the mechanics of PP alloys performance. The chemical reaction between the functional groups in the ends or segments of general engineering plastics and reactive polyolefins produces copolymers, thereby improving the compatibility of the alloy. The functional groups in reactive polyolefins are mostly acid anhydrides, epoxy groups, carboxyl groups and the like. The functional group-containing monomers such as maleic anhydride and PP are melt-kneaded to prepare graft polymers.

Polyester is a widely used engineering plastic. PET is a polar crystalline polymer. PP can be blended with PET through functionalization or adding compatibilizers. The PP-g-AA/PET blend has high melt strength, is easy to pelletize, and has good extrusion molding processability. Due to the chemical reaction between PP-g-AA and PET during processing, hydrogen bonds may be formed, and the mechanical properties of the blend are good. When PET/PP is 80/20, the elastic modulus of the blend reaches its maximum value, but the PP must be modified before blending. Using PP-g-MI (maleimide) and PET melt blending, the research results show that as the content of PP-g-MI increases, the cold crystallization temperature of PET in the blend decreases. The compatibility of PP-g-MI/PET is much higher than that of pure PP/PET. At the same time, PP-g-MI improves the crystallization and processing properties of PET. It is a polar crystalline polymer. PP is functionalized or added The compatibilizer can be blended with PET. The PP-g-AA/PET blend has high melt strength, is easy to pelletize, and has good extrusion molding processability. Due to the chemical reaction between PP-g-AA and PET during processing, hydrogen bonds may be formed, and the mechanical properties of the blend are good.