硫酸盐竹浆纤维素聚合度对纸张性能的影响

Influence of the Degree of Polymerization of Cellulose on Paper Properties in Kraft Bamboo Pulp

关键词:  纤维素聚合度  高聚合度竹浆  硫酸盐法制浆  力学性能

Key Words:degree of polymerization of cellulose  bamboo pulp with high degree of polymerization  kraft pulping  mechanical properties

摘要:本研究以慈竹为原料，采用硫酸盐法蒸煮，通过正交实验系统研究了蒸煮条件对竹浆纤维素聚合度（DP）的影响，确定了导致竹浆纤维素DP显著下降的主要因素，并优化了高聚合度竹浆的制备工艺。通过控制漂白药品用量和时间，制备了形态相近、纤维素DP不同的4种竹浆，进一步探究了纤维素DP对纸张力学性能的影响。结果表明，蒸煮条件对竹浆纤维素DP的影响顺序为：用碱量>蒸煮最高温度>保温时间>硫化度，其中用碱量和蒸煮温度是导致纤维素DP显著下降的关键因素。优化后的制备条件为用碱量12%，蒸煮最高温度140 ℃，硫化度10%，保温时间50 min，此条件下制得的竹浆纤维素DP达2 186，纸浆得率达57.9%，木质素含量为9.12%。此外，纤维素DP的下降导致竹纤维强度显著降低，进而影响纸张的零距抗张强度、耐破指数和撕裂指数，但对拉伸强度几乎没有影响。

Abstract:In this study， Bambusa emeiensis was used as the raw material to prepare bamboo pulp via kraft pulping. A systematic orthogonal experimental design was employed to investigate the effects of various pulping conditions on the degree of polymerization （DP） of cellulose of bamboo pulp. The key factors responsible for the rapid decrease of cellulose DP in bamboo pulp cellulose were identified， and the optimal process conditions for producing high cellulose DP bamboo pulp were determined. Subsequently， four types of bamboo pulp with similar morphology but varying cellulose DP were prepared by adjusting the amount and duration of bleaching agents to examine the effect of cellulose DP on the mechanical properties of the resulting paper. The results showed that the influence of pulping conditions on the cellulose DP followed the order： alkali dosage>maximum cooking temperature>holding time>sulfidity. Among these factors， alkali dosage and cooking temperature were the primary contributors to the substantial reduction in cellulose DP. The optimal conditions of kraft pulping were found to be alkali dosage of 12%， maximum cooking temperature of 140 ℃， sulfidity of 10%， and holding time of 50 min. Under these conditions， the cellulose DP of bamboo pulp exceeded 2 186， the pulp yield reached 57.9%， and the lignin content of pulp was 9.12%. Furthermore， the decrease in cellulose DP of bamboo pulp resulted in a sharp reduction in the intrinsic strength of the bamboo fibers， leading to declines in the zero-span tensile strength， burst index， and tear index of the paper， while the tensile strength was almost unaffected.