正庚烷为溶剂高温下制备聚二甲基硅氧烷渗透汽化膜的研究

摘要

为了缩短交联时间,本文以正庚烷作为溶剂,通过提高交联温度来制备聚二甲基硅氧烷(PDMS)渗透汽化膜.研究了交联温度和催化剂用量对交联膜的拉伸模量、水与乙醇的接触角以及膜在水和乙醇中溶胀度的影响.以质量分数10％的乙醇水溶液为料液,研究了分离温度对膜渗透汽化性能的影响.研究发现,在交联温度75℃下交联时间为0.63h,这仅是在20℃时交联时间(7.8 h)的十分之一.交联温度为75℃时制备的膜的杨氏模量是90℃时制备膜的2倍.随着交联温度的升高,PDMS膜的杨氏模量逐渐变小;膜在水中的溶胀度较低,膜在乙醇中的溶胀度很高.催化剂的用量对膜的杨氏模量和溶胀度没有明显影响.此外,实验发现交联温度和催化剂用量对膜的疏水性没有明显影响.对于10％乙醇水溶液的渗透汽化分离实验表明,在交联温度为75℃条件下制备的膜的分离因子达到7.74.%In order to reduce the crosslinking time by increasing the crosslinking temperature,n-heptane was used as solvent to prepare PDMS pervaporation membranes.The paper studied the effects of crosslinking temperature and catalyst content on the crosslinked membrane tensile modulus,the contact angle of water and ethanol,and the swelling degree in water and ethanol.With 10％ (mass fraction) ethanol aqueous solution as the feed liquid,it was studied that the separation temperature effected on the performance of pervaporation membrane.It was found that the crosslinking time at 75 ℃ was 0.63 h,which was only one-tenth of the crosslinking time at 20 ℃ (7.8 h).The tensile modulus of the PDMS membrane prepared at 75 ℃ was twice as the PDMS membrane prepared at 90 ℃.The increase in crosslinking temperature resulted in the deterioration of the tensile strength of the membranes,compared with the swelling degree in water,the swelling degree in ethanol was large.The change in the catalyst content showed no obvious effect on the tensile modulus and swelling degree.Both the crosslinking temperature and catalyst content exerted nearly no influence on the hydrophobic property of the membrane.Pervaporation separation experiment with 10％ ethanol aqueous solution showed the separation factor of the PDMS membrane prepared at 75 ℃ reached 7.74.