木粉热处理对WPC耐腐性能及力学性能的影响

采用180、200和220℃分别热处理0、1、2和3 h后的马尾松木粉与高密度聚乙烯(HDPE)复合制备木塑复合材料(WPC),并研究热处理木粉对复合材料的耐白腐、褐腐能力及其弯曲性能的影响,通过环境扫描电镜(ESEM)观察分析WPC试样腐朽前后的表面微观形貌。结果表明,处理温度和时间对质量损失率的影响均显著,菌种的影响不显著;木粉热处理后WPC的质量损失率均有不同程度的降低,且随处理温度的升高、时间的延长,降低幅度明显增大,200℃、3 h处理后的木粉使WPC的质量损失率降低最多,经白腐菌和褐腐菌侵蚀后,分别较对照降低了53.52%和57.83%。腐朽前后WPC试样表面菌丝侵蚀情况的ESEM观察结果也进一步说明木粉热处理具有提高WPC耐腐性能的作用。而木粉热处理使WPC的弯曲强度均有所降低,与对照相比最多降低了4.57%,但弯曲模量总体呈先增后减的趋势,温度和时间对WPC弯曲强度和弯曲模量的影响均不显著。

Influence of thermally treated of wood flour on decay resistance and mechanical properties of wood plastic composites

In this paper, the wood flour(WF) of Pinus massoniana Lamb.were thermally treated at 180~220 ℃ for 0, 1, 2 and 3 h, respectively, then the thermally treated WF was mixed with HDPE to produce WF/HDPE composites (WPC).The decay resistance against the white-rot(Trametes versicolor) and brown-rot(Antrodia sinuosa) fungi, the flexural modulus of rupture and modulus of elasticity of the composites were investigated, and the microstructure of the composites before and after being infected by the 2 evaluated fungi were observed by environmental scanning electron microscope(ESEM).The results showed that thermal treatment temperature and time significantly influenced the mass loss rate (P<0.05), but the stains has no significant variation(P>0.05).It was observed that the mass loss rate of the composites made with WF heat treated all had a decreasing trends compared to reference samples, and their difference varied as the processing temperature increase and time lengthening, the mass loss rate of the composites made with WF treated at 200 ℃ for 3 h infected by T.versicolor and A.sinuosa were the lowest than the other treatments with a decrease rate 53.52% and 57.83% compared to CK, respectively.ESEM observation of fungi growth on the surface of composites before and after being infected by the two fungi also suggested that thermal treatment also improved the decay resistance against the fungi.The results of the flexural properties of the composites showed that the flexural modulus of rupture decreased after WF were treated with the biggest 4.57% decrease compared to reference samples, and the modulus of elasticity of the composites filled with heat-treated WF increased at first and then decreased with the increasing thermal treatment temperature and lengthening thermal treatment time.Thermal treatment temperature and time has no significantly influenced on the flexural modulus of rupture and the modulus of elasticity.