不同常压蒸煮条件下荛花纸干热老化性能研究

Research on Dry Heat Aging Resistant Properties of Wikstroemia Paper under Different Cooking Conditions at Atmospheric Pressure

关键词:  荛花皮  干热老化  蒸煮  耐久性

Key Words:wikstroemia  dry heat aging  cooking  durability

摘要:荛花纸是一种优质的手工纸，坚韧耐久。为更好地评价和提高其耐久性，以荛花皮为原料，K₂CO₃和NaOH为蒸煮化学品，在常压、100 ℃的条件下蒸煮、抄纸，通过干热加速老化实验，探究不同蒸煮条件对荛花纸耐久性的影响，并借助纸张白度、强度及化学性能等进行分析评价。结果表明，蒸煮条件影响纸张耐久性，弱碱蒸煮可明显提高纸张的耐老化性，K₂CO₃（用量12%，蒸煮时间6 h）蒸煮所得荛花纸耐久性较好，老化80天后纸张抗张强度、耐折度、撕裂度及聚合度的保留率分别为94.2%、19.6%、47.9%和66.9%。蒸煮程度越大，纸张返黄程度越大，纤维长度、聚合度及纸张强度下降趋势越显著，纸张酸化越严重。此外，随着老化时间的延长，纸张中纤维素结晶度下降、羧基含量增加，纤维表面出现皱缩、纤维脆化等现象。

Abstract:Wikstroemia paper was a high-quality handmade paper with excellent tenacity and durability. In order to better evaluate and improve its durability， pulping and paper making were carried out at atmospheric pressure and 100 ℃ with wikstroemia plants as raw material， K₂CO₃ and NaOH as cooking agents， respectively. The dry heat accelerated aging experiments were conducted to study the effect on the durability of paper with different cooking conditions. The durability of paper was evaluated by analyses of whiteness， strength and chemical properties. The results showed that the durability of paper greatly depended on cooking condition， and using a mild alkaline as cooking agent could obviously increase the aging resistant property. The best durability of wikstroemia paper could be obtained by cooking condition of K₂CO₃ with concentration of 12% for 6 h at atmospheric pressure. The tensile strength， folding endurance， tearing strength and retention rate of polymerization degree after aging for 80 days were 94.2%， 19.6%， 47.9% and 66.9%， respectively. With the cooking level increasing， the yellowing of the paper would be accelerated. Meanwhile， the fiber length， polymerization degree and mechanical properties of paper declined more significantly. And the acidification of paper would intensify. The results also indicated that with the extension of aging time， the crystallinity of cellulose in paper would decrease， while the content of carboxyl would increase， and the surface of the fiber exhibited wrinkling and embrittlement.