聚酯型聚氨酯弹性体在酸碱浸泡下的失效行为研究

Study on Failure Behavior of Polyester-based Polyurethane Elastomers under Acid and Alkali Immersion

聚氨酯弹性体在苛刻溶液环境中会发生变形、开裂、脱落等老化问题,严重影响船舶的安全性。因此,对聚氨酯弹性体的环境可靠性研究迫在眉睫。研究了两种聚氨酯弹性体PCL-PU和PBA-PU在10%HCl溶液和15%NaOH溶液浸泡下的失效行为,探讨了软段单体结构对聚氨酯弹性体的力学性能、接触角、宏观形貌、微观结构和热稳定性的影响。结果表明,PCL-PU和PBA-PU在10%HCl溶液浸泡28d后,拉伸强度均下降50%;同时,在15%NaOH溶液浸泡120d后的拉伸强度分别下降50%和45%。聚酯型聚氨酯弹性体在酸碱浸泡条件下力学性能和热稳定性的降低主要与硬段异氰酸酯水解和软段酯键的断裂有关。

There wil be some aging problems when the polyurethane elastomer in harsh solution environment,such as deformation,crack and excoriation,etc.,which seriously affect the safety of ships.Therefore,the study on the environmental reliability of polyurethane elastomers is urgent.The failure behavior of two kinds of polyurethane elastomer,PCL-PU and PBA-PU,immersed in 10%HCl solution and 15%NaOH solution is studied,and the influences of the soft segment monomer structure on the mechanical properties,contact angles,macroscopic morphology,microstructure and thermal stability of polyurethane elastomer are investigated.The results show that the tensile strength of PCL-PU and PBA-PU decreases by 50%after soaking in 10%HCl solution for 28 d.Meanwhile,the tensile strength decreases by 50%and 45%after being immersed in 15%Na0H solution for 120 d.The decrease of mechanical properties and thermal stability of polyester polyurethane elastomers under acid and alkali immersion is mainly related to the hydrolysis of isocyanate in hard segment and the fracture of ester bond in soft segment.