Polypropylene is a high crystallinity material, the lightest among commonly used plastics, with a density of only 0.91g/cm3 (smaller than water), light weight, good toughness, and good chemical resistance. PP has good wear resistance, better than HIPS, and has good high temperature impact resistance. The hardness is lower than ABS and HIPS, but better than PE. And has a higher melting point.
Since homopolymer polypropylene is very brittle when the temperature is higher than 0 °C, many commercial polypropylene materials are random copolymers with 1% to 4% ethylene added, or block copolymers with a higher proportion of ethylene content. thing. Copolymer polypropylene materials have lower heat distortion temperature (100 ° C), low transparency, low gloss, low rigidity, but have stronger impact strength. The strength of polypropylene increases with increasing ethylene content.
Polypropylene has the following characteristics:
1. Polypropylene is a colorless, non-toxic, odorless, thermoplastic crystalline polymer.
2. The transparency of polypropylene has a great relationship with the crystallinity. In order to improve the transparency and reduce the crystallinity, in the production of pp film, the water quenching method should be used to extrude and blow the film, so that the PP has no time to crystallize and improve the transparency.
3. Polypropylene has good chemical resistance, acid resistance, alkali resistance, grease resistance and solvent resistance.
4. The tensile strength and impact strength of polypropylene are higher than pe, but it is brittle at low temperature, and it is easy to use PP to age by heat and light.
5. Polypropylene has excellent electrical insulation properties and low surface energy. Like PE, PP is prone to static electricity.
