桉木质素磺酸钙与接枝共聚引发剂反应导致的结构变化

Changes in Calcium Lignosulfonate from Eucalyptus Influenced by Initiators in Graft Copolymerization

为阐明引发剂(H2O2-FeCl2,K2S2O8与H2O2-CaCl2)在桉木质素磺酸钙(HLS-Ca)接枝共聚中的作用,采用差示化紫外、FTIR、UV和特性黏度分析等方法研究上述引发剂对HLS-Ca结构的影响。结果表明:HLS-Ca会与接枝反应体系中的引发剂发生相互作用从而改变HLS-Ca的结构与反应活性。在本文研究条件下,HLS-Ca经Fenton(H2O2-FeCl2)和K2S2O8引发剂处理后苯环结构保持稳定;酚羟基(Ph-OH)含量降低,但其未被氧化为类醌型结构;芳基醚键含量增加、黏均分子质量增加。H2O2-CaCl2处理HLS-Ca后,HLS-Ca中Ph-OH含量降低,部分Ph-OH被氧化为羰基;HLS-Ca的苯环结构受到破坏,黏均分子质量降低。

The grafting method is widely adopted for developing lignin-based polymer materials with high properties. Aimed at studying various initiators （Fenton, K2S2O8, H2O2-CaCl2） effects on calcium lignosulfonate from eucalyptus （HLS-Ca） in graft copolymerization, HLS-Ca was treated by the above initiators, respectively. Changes in the functional composition of HLS-Ca were investigated by using Difference UV, FTIR, UV spectroscopy and intrinsic viscosity （[η]） methods. The results show that the changes in the structure and reactivity of HLS-Ca were observed due to some certain reactions between it and initiators. Under our experimental conditions, the benzene ring stable against the oxidation of Fenton and K2S2O8 initiators; the content of phenolic hydroxyl （Ph-OH） group decreases under the incubation of Fenton and K2S2O8 initiators though it’s not oxidized to the structure like quinone; the content of aryl-ether, [η] and viscosity-average molecular weight （Wη） increase. Under the treatment of H2O2-CaCl2 initiator, the content of Ph-OH group decreases dramatically and it could be transformed to carbonyl structure. The destruction of benzene ring results in the decrease in the [η] and Wη for HLS-Ca.