纤维素的酸活化

Acid Activation of Cellulose

以合成醋酸丙酸纤维素中的酸活化为例对纤维素的酸活化进行了研究。发现酸活化温度和活化时间对结晶破坏影响很大,在活化温度为40～60℃、活化时间小于2 h时,结晶破坏速率较快;活化温度对纤维素平均聚合度的影响较大,当活化温度高于80℃时,纤维素降解显著;活化前期,平均聚合度下降明显;活化过程通氮可以减少纤维素的氧化和水解;红外和X-射线衍射结果表明酸活化过程中主要发生物理溶胀,除了降解,无其它化学反应发生。

In order to prepare cellulose acetate-propionate, the acid activation of cellulose was investigated in this paper. It was found that acid activation temperature and time had significant influences on the destroying of cellulose crystals. The crystallinity decrease rate was great when the activation temperature ranged from 40 to 60℃ and the activation time was less than 2 h. The degradation of cellulose increased as the activation temperature increased, which led the decrease of polymerization degree of cellulose, especially in the initial activation stage. IR and XRD results showed that the physical swelling is main action in the acid activation process, with no chemical reaction except of the degradation.