Influence of molecular weight on molding efficiency and properties of sintered UHMWPE thick-size products

Ultra-high molecular weight polyethylene (UHMWPE) is a kind of high performance polymer. But sintering-Molded UHMWPE thick products have the problems of long processing time and structural heterogeneity in products. Here, we compared the time required to complete sintering of UHMWPE thick products with different molecular weights, and found that the higher the molecular weight, the longer the time it took to complete sintering. With the increase of sintering time, the homogeneity of UHMWPE thick products can be improved continuously and will reach a saturation state, at which increasing the sintering time will not change various properties of the products. We compared several kinds of properties of UHMWPE thick products with different molecular weights and found that with the increase of molecular weight, the hardness, Young's modulus, tensile strength, and yield strength of the products barely change, but the elongation at break and the impact strength decrease. Finally, we attribute this phenomenon to the thickness increase of amorphous region.