Blending Modification of Ultra High Molecular Weight Polyethylene

Ultra high molecular weight polyethylene (UHMWPE) refers to polyethylene with a relative molecular mass of more than 1,000,000. UHMWPE has the same structure as HDPE except that its relative molecular mass is two orders of magnitude higher than that of HDPE. Due to its ultra-high relative molecular mass, UHMWPE has a unique character: high tensile strength, excellent abrasion resistance and extremely high melt viscosity. Many of its mechanical properties and performance have reached or exceeded the level of engineering plastics and can be used to make mechanical parts. Due to the high viscosity of the melt, it is difficult to form and shape, making its application limited and it must be modified. The use of blending with other polymers to improve the melt flow of UHMWPE is currently the most effective and economical method. The commonly used methods are as follows:
1) Blending with HDPE can reduce the melt viscosity and the mechanical properties are basically not lost. It is better to add a small amount of inorganic nucleating agent in the blending system. For example: with 79.8% of UHMWPE's 19.9% ​​of HDPE, 0.3% of wollastonite after blending, extrusion molding, the product maintains a variety of UHMWPE excellent performance;
2) Blending with low molecular weight LDPE (polyethylene wax) can significantly reduce melt viscosity and improve processing performance. However, the excellent mechanical properties of UHMWPE are lost. If a fluidity modifier (a kind of petroleum resin) is added at the same time, the mechanical properties can be guaranteed without loss or loss;
3) Blending with liquid crystal polymers, utilizing the inherent structural features of liquid crystal polymers, a new type of engineering material with better mechanical strength than HMWPE can be obtained while significantly improving the processing performance.