What is the difference between PP and PE?

The density of PP is less than that of PE;

In terms of mechanical strength, PP is higher;

But flexibility, impact resistance and PE are better;

If the film is made, the transparency of PP is better than that of PE, but the sealing temperature and heat sealing strength are better.

In addition, in terms of temperature resistance, PP is also higher than PE, and generally PP can withstand pasteurization temperature.

PP:

Sports:

Extended data:

1. Polypropylene, English name: polypropylene (PP), Japanese name: ポリプロピレン, molecular formula: (C3H6) n. CAS registration number: 9003-07-0, is a kind of polymerization product of propylene.

According to the arrangement position of methyl groups, they can be divided into isotactic polypropylene, atactic polypropylene and syndiotactic polypropylene.

The melt mass flow rate (MFR) of PP is usually 1~ 100. PP with low MFR has better impact resistance, but lower tensile strength. For materials with the same MFR, the impact strength of poly type is higher than that of homopolymer type. Due to crystallization, the shrinkage of PP is quite high, generally 1.6~2.0%.

Polypropylene is usually modified by adding glass fiber, powder additive or elastomer. Adding 30% glass fiber can reduce the shrinkage to 0.7%. Both homopolymer and polymer PP materials have excellent moisture absorption resistance, acid and alkali corrosion resistance and solubility resistance.

But it is not resistant to aromatic hydrocarbon (such as benzene) solvents and chlorinated hydrocarbon (carbon tetrachloride) solvents. The oxidation resistance of PP at high temperature is not as good as that of PE.

2. Polyethylene (PE for short) is a thermoplastic resin polymerized from ethylene.

In industry, it also includes * * * polymers of ethylene and a small amount of α-olefins. Polyethylene is odorless and non-toxic, feels like wax, and has excellent low temperature resistance (the lowest service temperature can reach-100 ~-70℃), good chemical stability and resistance to most acids and bases (not oxidative acids). Insoluble in general solvents at room temperature, low water absorption and excellent electrical insulation.

On October 27th, 2065438+071KLOC-0, the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization was preliminarily sorted out for reference. Polyethylene is in the list of three types of carcinogens.

References:

Polypropylene PP Baidu encyclopedia

Polyethylene PE Baidu Encyclopedia