聚醚砜与聚偏氟乙烯膜的力学性能研究

The Research for the Mechanical Properties of PES and PVDF Membranes

本文以聚醚砜（PES）与聚偏氟乙烯（PVDF）为膜材料,采用相转化法制备分离膜,利用自制的小型拉力机测试膜的断裂强度。研究了在室温下PES膜与PVDF膜经过浓度为10%∽50%的盐酸、氢氧化钠、柠檬酸溶液分别处理后对膜力学性能的影响,并利用红外光谱表征,分析了浓度为50%的酸碱溶液处理前后膜力学性能发生变化的可能原因。结果表明,经过同一种类的酸碱处理后,膜的断裂强度随着酸碱浓度的增加而降低;PES膜的耐酸性明显优于其耐碱性;PVDF膜在浓度为50%的柠檬酸中浸泡后,断裂强度下降的幅度最大。通过全反射红外扫描,得知PES与PVDF膜经过酸碱处理后,其特征峰位置基本保持不变,但吸收峰都有不同程度的减弱,说明经酸碱处理后,聚合物官能团的活性降低了,而PES与PVDF并没有与酸碱发生化学反应。

In this paper,Polyethersulfone（PES） and Polyvinylidene fluoride（PVDF） were used as raw materials,and phase transformation method was used to prepare separation membranes,the breaking strength of all the membranes were measured by a self–made tester. The PES and PVDF membranes were soaked in the hydrochloric acid,citric acid and sodium hydroxide solution with the concentration of 10% to 50%,respectively. The effects of acids and alkali to the breaking strength of membranes were investigated in room temperature. And a series of infrared test were done to analyze the reasons for the change of the mechanical properties of the membranes soaked in acids and alkali solution with the concentration of 50%. Experimental results showed that the breaking strength was decreased with the increasing of the concentration of same kind of acids and alkali. It was also found that the acid resistance of PES membrane was superior to its alkali resistance,and the decreasing amplitude of breaking strength of PVDF membrane which was soaked in 50% citric acid could be highest. By total reflection infrared scanning,we learned that the characteristic peaks of the PES and PVDF which were treated by acids and alkali were essentially unchanged,but the absorption peaks had a different degree of weakened,it was showed that the activity of the functional groups might be reduced by acid and alkali treatment,PES and PVDF did not react with the acids and alkali.