单 位：
北京林业大学木材科学与工程北京市重点实验室木质材料科学与应用教育部重点实验室
关键词：
聚乳酸;木聚糖酶;竹粉;热稳定性;力学性能
摘 要：
植物纤维与树脂基材料在复合过程中存在相容性差的问题。为拓宽生物酶在植物纤维增强聚合物方面的应用,探讨利用木聚糖酶进行生物改性对植物纤维产生的影响,以生物酶木聚糖酶为改性剂、聚乳酸(PLA)作为基质,利用热压成型-冷压脱模工艺制备了改性竹粉/聚乳酸复合材料。采用单因素试验,控制木聚糖酶的浓度,通过傅里叶转换红外光谱(FT-IR)、力学测试、扫描电子显微镜(SEM)、热重分析(TG或TGA)等分析方法,研究了不同浓度木聚糖酶改性竹粉对复合材料性能的影响。结果表明:FT-IR显示,随着木聚糖酶浓度变大,半纤维素被逐渐降解,2.67 mg/L质量浓度时降解最佳;力学性能显示,当木聚糖酶的质量浓度为2.67 mg/L时,相比未处理组,复合材料的弯曲强度、拉伸强度分别提高15.0%和85.7%,但冲击强度降低5.2%,优于其他浓度;热重分析显示,当木聚糖酶的质量浓度为2.67 mg/L时,纤维最先被降解,热稳定性弱于其他组; SEM结果显示,竹粉经过木聚糖酶处理后,半纤维素被降解,纤维表面变得粗糙,与PLA结合强度变大,2.67 mg/L质量浓度时是复合材料性能最佳的水平。
译 名：
Influence of xylanase treatment on properties of bamboo powder/polylactic acid composites
作 者：
HAO Chengyi;ZHANG Kaiqiang;SONG Wei;YIN Hongnian;ZHANG Shuangbao;Beijing Key Laboratory of Wood Science and Engineering,MOE Key Laboratory of Wooden Material Science and Application,Beijing Forestry University;
关键词：
polylactic acid(PLA);;xylanase;;bamboo powder;;thermal stability;;mechanical properties
摘 要：
There are problems in the process of compounding plant fibers with resin-based materials. Xylan is an important component of hemicellulose,however,xylanase is a generic name for a class of complex enzymes that specifically degrade xylan. It is a complex glycoside hydrolase that can degrade xylan deposited on the surface of fibers. In order to broaden the application of biological enzymes in plant fiber reinforced polymers and to explore the impact of the biological modification on plant fibers,the bamboo powder/polylactic acid( PLA) composites were prepared using the hot pressing-cold demolding technology,and the bio-enzyme xylanase as a modifier and PLA as a matrix. The performances of bamboo powder/PLA composites were tested with the Fourier transform infrared spectroscopy( FT-IR),mechanics,scanning electron microscope( SEM) and thermogravimetry( TG). The single-factor experiments were used to control the concentration of xylanase and study the effect of different concentrations of xylanase on properties of composites. The results showed that,when the concentration of xylanase was 2.67 mg/L,the FTIR results showed that the hemicellulose was gradually degraded as the concentration of xylanase became larger,and the xylanase disrupted the connection of lignin-sugar complex( LCC),which increased the phenolic hydroxyl group and the alcoholic hydroxyl groups at the Cαand Cβ positions of the lignin structural unit. At that concentration of xylanase,compared with the untreated group,the flexural strength and tensile strength of the composites increased by 15.0% and 85.7%,respectively,but the impact strength decreased by 5.2%,which was better than other groups. The thermogravimetry( TG) examination showed that hemicellulose was firstly to be degraded,and the thermal stability was weaker than other groups. When the concentration of xylanase was 1.33 mg/L,the thermal stability was better than any other group. The SEM images showed that,after the treatment of xylanase,in the bamboo powder the hemicellulose xylan was degraded,the fiber surface become rough,and the bonding strength with PLA was increased within a certain concentration of xylanase. In summary,the addition of xylanase can dissolve part of the hemicellulose,and the effect on the surface of plant fibers was somewhat enhanced,which was conducive to the improvement of the pyrolysis and mechanical properties of the composite material. After the analysis of the results,the concentration of xylanas was 2.67 mg/L,in that condition,the best performance of the bamboo powder/polylactic acid composites can be obtained.
