The modified varieties of polyethylene mainly include chlorinated polyethylene, chlorosulfonated polyethylene, cross-linked polyethylene and blended modified varieties.
Chlorinated polyethylene: random chloride obtained by partially replacing the hydrogen atom in polyethylene with chlorine. Chlorination is initiated by light or peroxide and is mainly produced by aqueous suspension in industry. Due to the difference in the molecular weight of the raw material polyethylene and its distribution, branching degree and chlorination degree after chlorination, chlorine atomic distribution and residual crystallinity, chlorinated polyethylene from rubber to hard plastic can be obtained. The main use is as a modifier of polyvinyl chloride to improve the impact resistance of polyvinyl chloride. Chlorinated polyethylene itself can also be used as electrical insulation and floor materials.
Chlorosulfonated polyethylene: When polyethylene reacts with chlorine containing sulfur dioxide, part of the hydrogen atoms in the molecule are replaced by chlorine and a small amount of sulfonyl chloride group to obtain chlorosulfonated polyethylene. The main industrial production method is the suspension method. Chlorosulfonated polyethylene is resistant to ozone, chemical corrosion, oil, heat, light, wear and tensile strength, and is an elastomer with good comprehensive properties, which can be used to make equipment parts that contact food.
Cross-linked polyethylene: Cross-linked polyethylene that is made into a network or body shape by radiation (X-ray, electron rays or ultraviolet radiation, etc.) or chemical methods (peroxide or silicone crosslinking). Among them, the silicone crosslinking method is simple process, low operating cost, and molding and crosslinking can be carried out step by step, and blow molding and injection molding should be used. The heat resistance, environmental stress cracking resistance and mechanical properties of cross-linked polyethylene are greatly improved than that of polyethylene, and it is suitable for large pipes, cables and wires and rotational molding products.
Blending modification of polyethylene: After blending linear low-density polyethylene and low-density polyethylene, it can be used to process films and other products, and the product performance is better than low-density polyethylene. Polyethylene and ethylene propylene rubber blends produce a wide range of thermoplastic elastomers.
