1, which is safer, polypropylene or polyethylene? "Polypropylene and polyethylene are safe food-grade plastics, but polypropylene is resistant to high temperature and low temperature, while polyethylene is the opposite. Secondly, the aging resistance of polypropylene is weaker than that of polyethylene and its flexibility is also poor. But because polypropylene is the only plastic that can be used in microwave ovens, it is also made into lunch boxes, plastic wrap and so on. "

2. Polypropylene can resist the corrosion of acid, alkali, salt solution and various organic solvents below 80℃, and can be decomposed under high temperature and oxidation. Polypropylene is widely used in clothing, blankets and other fiber products, medical devices, automobiles, bicycles, parts, pipelines, chemical containers and food and drug packaging.

What is the difference between polypropylene and polyethylene?

1, the difference between air permeability and water permeability

The permeability and water permeability of polypropylene are lower than that of polyethylene.

2, the difference of anti-aging ability

There is methyl tertiary carbon on the long chain of polypropylene, which is unstable. In use, long-term contact with copper is strictly prevented to avoid "copper loss" in use, so its aging resistance is not as good as that of polyethylene.

3. Difference in chemical stability

Besides fuming nitric acid and fuming sulfuric acid, polypropylene has good chemical resistance. Using 80% sulfuric acid and concentrated hydrochloric acid in the laboratory can reach 100℃ without damaging polypropylene.

4. Difference in heat resistance

Polypropylene plastic products can be used for a long time at 100- 120℃; However, the impact strength at low temperature drops sharply, and the impact strength at 0℃ is half that at 20℃.

5, directional pull difference

Polypropylene has high tensile strength, good bending properties and increased flexibility. It has been bent for 6.5438+0 million times, and the bent part is still white. Its rigidity and tensile strength are also better than polyethylene.