PP material generally refers to polypropylene
Polypropylene is a thermoplastic resin made by the polymerization of propylene.There are three kinds of isotactic polypropylene, atactic polypropylene and syndiotactic polypropylene according to the position of methyl.
If the methyl groups are arranged on the same side of the molecular main chain, it is called atactic polypropylene. If the methyl groups are arranged on both sides of the molecular main chain, it is called metactic polypropylene. When the methyl groups are arranged alternately on both sides, it is called metactic polypropylene.In general industrial polypropylene resins, the content of isotactic structure is about 95%, the rest is atactic or isotactic polypropylene.Industrial products are mainly composed of isotactic substances.Polypropylene also includes a copolymer of propylene with a small amount of ethylene.Usually a translucent colorless solid, odorless and non-toxic.The melting point can be as high as 167℃ because the structure is regular and highly crystallized.Heat resistance, corrosion resistance, products can be used steam disinfection is its outstanding advantages.Low density, is the lightest universal plastic.The disadvantage is low temperature impact resistance is poor, easy to aging, but can be overcome by modification.
The copolymer type PP material has a lower thermal deformation temperature (100℃), low transparency, low gloss, low rigidity, but has a stronger impact strength, the impact strength of PP increases with the increase of ethylene content.The Vicat softening temperature of PP was 150℃.Due to the high crystallinity, the surface stiffness and scratch resistance of this material are good.There is no environmental stress cracking problem in PP.
The melt mass flow rate (MFR) of PP is usually between 1 and 100.The PP material with low MFR has better impact resistance but lower tensile strength.For materials with the same MFR, the impact strength of the copolymerization is higher than that of the homopolymerization.Due to crystall