木聚糖酶处理对西南桦木/HDPE复合材料性能的影响

采用木聚糖酶溶液对西南桦木粉进行处理，并利用热压成型工艺制得西南桦木/高密度聚乙烯（HDPE）复合材料，考察酶溶液浓度、处理时间及温度对西南桦木/HDPE复合材料拉伸强度、弯曲强度等力学性能的影响，从而获得木聚糖酶处理的最佳工艺条件。借助傅里叶红外光谱分析技术和扫描电子显微镜，分析木聚糖酶处理后西南桦木纤维的化学官能团变化和西南桦木/HDPE复合材料的断面形貌。结果表明：木聚糖酶处理能够增强西南桦木/HDPE复合材料的界面结合。在木聚糖酶溶液浓度为2.67 mg/L，温度为40℃，pH值为4.5的条件下处理2 h后，西南桦木粉的纤维素相对含量及结晶度增加，半纤维含量减小，木质素相对含量增加；木纤维的材质变软、表面变得粗糙，增大了与塑料分子的接触面积，从而提高了西南桦木/HDPE复合材料的力学性能。

Effect of xylanase solution on material properties of betula alnoides/HDPE wood plastic composites

The betula alnoides wood powders are treated by xylanase solution. The betula alnoides/HDPE composites are prepared by hot-pressing forming technique. The effects of the solution reaction time, temperature and concentration on the tensile strength and the bending strength of the betula alnoides/HDPE composites are investigated. The optimum chemical reaction conditions of the betula alnoides wood powders in the xylanase solution are established. The transformation of chemical functional groups of the betula alnoides wood fibers are analyzed by FTIR and their morphologies of fracture surfaces are observed using SEM. The results show that the interfacial bonding in the betula alnoides/HDPE composites are enhanced after xylanase solution. After the wood fibers are treated in a xylanase solution of concentration 2.67 mg/L under the conditions of a temperature of 40℃ and a pH of 4.5 during 2 h, the relative content and crystallinity of cellulose and the relative content of lignin increase in the betula alnoides wood fibers, while the relative content of hemicellulose decrease. The comprehensive mechanical properties of the betula alnoides/HDPE composites are enhanced due to the increased interface area between plastic and treated wood fibers whose surface become softer and rougher.