羟丙基醋酸纤维素的合成及其膜的反渗透性

SYNTHESIS OF HYDROXYPROPYL CELLULOSE ACETATE AND PROPERTIES OF REVERSE OSMOSIS MEMBRANES

研究了羟丙基纤维素和羟丙基醋酸纤维素的合成。制备羟丙基纤维素的较佳反应温度为40℃左右和2小时或稍长,羟丙基含量随环氧丙烷浓度的增加而增加。在制备羟丙基醋酸纤维素时,随羟丙基含量的增加,所需醋化和水解的时间减少。以甘油-正丙醇或磷酸为添加剂,丙酮为溶剂经30～60s蒸发后制得了羟丙基醋酸纤维素反渗透膜。后者在20kg/cm^2下对氯化钠脱盐率可达95～98％,水通量1.0～2.1mL/cm^2·h,其使用温度上限比醋酸纤维素反渗透膜提高10℃以上。

The synthesis of hydroxypropyl cellulose (HPC) and hydroxypropyl cellulose acetate(HPCA) has been carrled out. The suitable conditions for HPC synthesis wcre: 40℃ and 2hours or more. The hydroxypropyl content of HPC increased linearly with the increase ofthe concentration of propylene oxide in the reaction system. With the hydroxypropyl contentbeing increased, the time needed for acetylation and hydrolysis could be shortened Additionof glycerin-n-propanol mixture or phosphoric acid as additives and evaporation for 30 to 60seconds appeared favorable to preparation of reverse osmosis membranes by casting technique.The membranes obtained bave 95～98% of NaCl rejection and 1.0～2.1 mL/cm2·h of waterflux under the operation pressure of 20kg/cm^2. The highest working temperature of HPCAmembrane is about 10℃ higher than that of CA membrane.