关键词: 棒状纳米微晶纤维素, 热降解, 炭化, 硫酸

Abstract:

In order to improve the thermal stability of the cellulose whiskers obtained by the hydrolysis with sulfuric acid , two methods were adopted to treat the cellulose whiskers. One is the repeated desulfation with heating at 60℃ to reduce the hydrosulfate content , and the other is the neutralization with NaOH solution to neutralize the hydrosulfate on the surface. The results indicate that both the two methods can effectively improve the thermal stability of cellulose whiskers. As compared with microcrystalline cellulose , cellulose whiskers have a second pyrolysis stage at high temperature (more than 400 ℃) except the primary pyrolysis stage , and the final char yields are very similar in amount (3.5% - 5.0%). All these above-mentioned findings show that , for cellulose whiskers , the presence of extemal catalyst can only change the thermal decomposition pathway , and that the thermal pyrolysis and the final char yield are determined by the characteristics of the nano-sized particles. Moreover , the profile analysis of thermo gravimetric derivative curves shows that there are two remarkably competitive reactions in the primary pyrolysis stage of cellulose whiskers.

Key words: cellulose whisker, thermal degradation, carbonization, sulfuric acid