酶处理对UF麦秸纤维板性能的影响

Influence of xylanase treatment on perproties of UF wheat-straw fiberboard

利用木聚糖酶预处理麦秸纤维,采用常规热压工艺制备脲醛树脂(UF)麦秸纤维板,并测试木聚糖酶处理前后UF麦秸纤维板的性能变化.结果表明:与未经木聚糖酶处理的UF麦秸纤维板相比,处理后的UF麦秸纤维板的内结合强度、弹性模量、静曲强度均显著提高.其中,内结合强度由0.34 MPa提高到0.67 MPa,弹性模量由2386.05 MPa提高到3121.75MPa,静曲强度由18.25 MPa提高到27.13 MPa;24 h吸水厚度膨胀率显著下降,由36.45%降至18.40%,且各项指标达到国家标准合格品的要求.木聚糖酶处理后的UF麦秸纤维复合材料具有较大的刚度和阻尼;酶处理前后复合材料的Tg分别为98和127℃.因此,麦秸纤维经木聚糖酶处理后压制的UF麦秸纤维板热稳定性更好.

The xylanase pretreated wheat-straw fiber was used to increase the interfacial properties between wheat-straw fiber and urea formaldehyde resin（UF） in order to improve properties of board.The UF fiberboard of wheat-straw was preparaed by conventional hot-pressing technology.The mechanical performances of UF fiberboard of wheat-straw were tested with universal mechanics experimental instrument and dynamic mechanical thermal analyzer.The results showed that the internal bond strength（IB）,modulus of elasticity（MOE）,modulus of rupture（MOR） of the fiberboard made with xylanase treated wheat-straw fiber were increased considerably,while the 24 h thickness swelling rate（24 h TS） was decreased significantly.The IB,MOE and MOR increased from 0.34 MPa to 0.67 MPa,2386.05 MPa to 3121.75 MPa,and 18.25 MPa to 27.13 MPa respectively.The 24 h TS decreased from 36.45% to 18.40%.All properties tested in this study met the product specification of National Standard for medium density fiberboard.The results from dynamic mechanical analysis（DMA） demonstrated that the xylanase treated UF fiberboard of wheat-straw had higher stiffness and damping.The glass transition temperature（Tg） of xylanase untreated UF fiberboard of wheat-straw and treated UF fiberboard of wheat-straw were 98 and 127 ℃,respectively,which indicated that treated UF fiberboard of wheat-straw was able to bear higher temperature.