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【目的】研究在两种不同芯层材料的复合体系下,增强材料含量与皮层厚度对共挤出(皮-芯结构)木塑复合材料弯曲与热膨胀性能的影响。【方法】以共挤出技术为加工工艺,选取短玻璃纤维(SGF)为皮层的增强材料,制备共挤出型(皮-芯结构)木塑复合材料(WPC)。分析了在芯层1与芯层2两种复合体系下,不同皮层厚度(1.0、1.2及1.6 mm)和皮层填料含量(0%、10%、20%、30%和40%)对共挤出型皮-芯结构WPC的弯曲性能和热膨胀性能的影响。【结果】当表面为纯的高密度聚乙烯(HDPE)时,在芯层1和芯层2两个复合体系中,皮层越厚则复合材料的热膨胀系数(LTEC)越高,其热膨胀性能越差;当SGF的加入量恒定时,其LTEC随着皮层厚度的增加而降低。当皮层的弯曲模量比芯层低时,共挤出木塑复合材料的弯曲模量随着皮层厚度的升高逐渐降低;当芯层的弯曲模量比皮层低时,共挤出木塑复合材料的弯曲模量随皮层厚度的升高而升高。皮层为SGF/HDPE材料时,在芯层1和芯层2两个复合体系中,随着皮层SGF的含量从0%增加到40%时,其弯曲性能显著性提高,LTEC显著降低。当皮层的LTEC值比芯层大时,皮层厚度的降低可以降低共挤出木塑复合材料的LTEC;当皮层的LTEC值小于芯层时,共挤出木塑复合材料的LTEC随皮层厚度的增加而减少。【结论】通过改性芯层可以提高皮-芯结构木塑复合材料的整体性能,其增强趋势与表层的增强趋势相似。
【Objective】 The effects of reinforcement and cortical thickness on the flexural and thermal expansion properties of co-extruded (skin-core) wood-plastic composites under two different core-material composites were investigated. 【Method】 Co-extrusion (sheath-core structure) wood-plastic composites (WPC) were prepared by using co-extrusion technology as the processing technology and short glass fiber (SGF) as the reinforcing material. The effects of different cortical thickness (1.0, 1.2 and 1.6 mm) and cortical filler content (0%, 10%, 20%, 30% and 40%) on coextrusion Effect of WPC Bending and Thermal Expansion Properties on an Extruded Skin-core WPC. 【Result】 When the surface is pure HDPE, the thicker the cortical layer in the two composite systems of core 1 and core 2, the higher the thermal expansion coefficient (LTEC) of the composite and the higher the thermal expansion coefficient Poor; when the amount of SGF added is constant, its LTEC decreases with the increase of cortical thickness. When the cortical flexural modulus is lower than the core, the flexural modulus of the co-extruded WPC decreases with the increase of the cortical thickness. When the core modulus is lower than the cortical, the WPC The flexural modulus of composites increases with the increase of cortical thickness. When the skin layer is SGF / HDPE, the bending properties of SGF / HDPE are significantly improved and the LTEC is significantly decreased in the two composite systems of core layer 1 and core layer 2 as the content of SGF in the cortex increases from 0% to 40%. When the cortical LTEC value is larger than the core layer, the cortical thickness reduction can reduce the LTEC of the co-extruded WPC. When the cortical LTEC value is smaller than that of the core layer, the LTEC of the cofused WPC composites decreases with the cortical thickness Increase and decrease. 【Conclusion】 Through the modified core layer, the overall properties of skin-core-structure WPC composites can be improved. The enhancement tendency is similar to that of surface layer.