CaSO_4晶须补强增韧聚氨酯弹性体机理的研究

提高聚氨酯弹性体的力学性能是聚氨酯研究领域里普遍关心的课题之一，一般采用刚性粒子和纤维类无机填料增强聚氨酯弹性体，但上述填料在提高强度的同时，会导致韧性降低，空易造成脆性断裂，因此填料能否同时补强增韧聚氨酯弹性体具有重要的实际应用价值，晶须是一种单晶纤维状材料，其直径极小，几乎不存在任何缺陷，由于内在的完整性，高度有序的原子排列，使其强度接近晶体理论－－原子间价键的强度，晶须凭借微细的直径、较短的长度、极高的强度，成为一种新型补强增韧剂，目前晶须的复合基体多为陶瓷基、金属基和树脂基，有关复合基体多为陶瓷基、金属基和树脂基，有关复合聚氨酯弹性体的理论及应用研究报道很少，本文制备了具有较高强度和韧性的CaSO4晶须／聚氨酯弹性体复合材料，通过微观分析揭示了CaSO4晶须对聚氨酯弹性体补强增韧的机理，并对其影响因素进行了讨论。

STUDY ON CaSO4 WHISKER REINFORCING AND TOUGHENING MECHANISMS FOR POLYURETHANE ELASTOMER

The CaSO4 whisker/polyurethane elastomer composites with high strength and high toughness are fabricated.The CaSO4 whisker reinforcing and toughening mechanisms for polyurethane elastomer are studied.The observation of the fracture surface by SEM and TEM shows that CaSO4 whisker reinforcing mechanism for polyurethane elastomer is mainly load transfering,while its toughening mechanism involves crack deflection and whisker pullout.The effects of dispersity of CaSO4 whisker and the interfacial bonding state on reinforcement and toughness are discussed.The results indicate that composites with 5%～10% CaSO4 whisker exhibit the best mechanical properties among the materials tested.Good bonding interface is formed between whisker and matrix after the surface of CaSO4 whisker being treated by silane coupling agent(KH-550).Better interfacial bonding state contributes to strength and toughness being fairly improved.