Effect of LLDPE on Aging Resistance and Thermal, Mechanical, Morphological Properties of UHMWPE/LLDPE Blends

Blends of ultra-high molecular weight polyethylene (UHMWPE) and different contents (0, 10, 20 and 30 wt%) of linear low-density polyethylene (LLDPE) with and without maleic anhydride-grafted LLDPE (LLDPE-g-MA) were prepared by melt blending and aging resistance, thermal and mechanical properties were evaluated. The degree of crystallinity increases with the content of LLDPE in the blends. On the other hand, the addition of compatibilizer agent modifies the crystallinity and the crystallite size. Non-compatibilized blends have excellent impact resistance properties and the addition of LLDPE-g-MA aids processing but decrease the impact resistance of the blends. Thermal and mechanical properties were greatly affected by thermal and water aging. The thermal aging leads to an increase in the degree of crystallinity and consequent a decrease in impact resistance.

本研究通过熔融共混法制备了超高分子量聚乙烯（ultra-high molecular weight polyethylene, UHMWPE）与不同添加量（0、10、20及30 wt%）的线性低密度聚乙烯（linear low-density polyethylene, LLDPE）的共混体系，其中分别添加与不添加马来酸酐接枝线性低密度聚乙烯（maleic anhydride-grafted LLDPE, LLDPE-g-MA）作为相容剂，并对其耐老化性能、热学性能与力学性能进行了表征评价。共混物的结晶度随LLDPE添加量的提升而升高。另一方面，相容剂的添加会改变共混物的结晶度与微晶尺寸。未添加相容剂的共混物具备优异的抗冲击性能，而添加LLDPE-g-MA虽有助于改善加工性能，却会降低共混物的抗冲击性能。热老化与水老化会对共混物的热学与力学性能产生显著影响。热老化会使共混物的结晶度升高，进而导致其抗冲击性能下降。