单板饰面黄麻毡/PF复合材料的性能研究

Study on the properties of veneer-laminated jute fiber/PF composites

使用酚醛树脂(PF)浸渍黄麻毡,再通过热压方式制备成复合材料,在热压的同时将单板覆盖到黄麻毡/PF复合材料表面。对制备的复合材料进行了弯曲性能、冲击性能和表面胶合强度测试。结果表明,随着麻纤维含量的提高(与树脂质量比为1∶9,2∶8,3∶7,4∶6),复合材料的弯曲性能和冲击性能也随之提高。纤维与树脂质量比为4∶6的黄麻毡/PF复合材料弯曲、冲击性能最好。与未饰面材料相比,经单板饰面后的复合材料弯曲和冲击性能得到大幅度提高(纤维与树脂质量比为4∶6的饰面黄麻毡/PF复合材料的弯曲模量为8 GPa,弯曲强度为70 MPa,冲击韧性为8.9 kJ/m^2)。饰面黄麻毡/PF复合材料的表面胶合强度随纤维含量的增加而下降,但都大于0.6 MPa,满足国家标准的要求。浸渍剥离长度均小于25 mm,也达到国家标准要求。通过扫描电子显微镜观察发现,树脂未完全进入麻纤维细胞腔,这有利于提高复合材料的冲击性能,同时降低材料密度;树脂填充于纤维束之间,结合紧密。利用来源充足、价格低廉的黄麻毡可以制备出性能良好的复合材料,经单板贴面不仅提高了复合材料的力学性能,而且能够起到装饰作用,研究结果为生物质纤维的利用提供了新途径。

In the present study,unwoven jute preform was impregnated with phenol formaldehyde(PF)resin and then prepared a composites by hot-pressing method.The veneer was laminated on the surface of the jute fiber/PF composites along with the hot-pressing.The test results showed that the mechanical properties of the jute fiber/PF composites increased with the increase of jute fiber content(10%,20%,30%and 40%),and the best performance presented at 40%of the jute fiber.When the jute fiber/PF composite was covered with wood veneer,its mechanical strengths were greatly improved(flexural modulus of 8 GPa,flexural strength of 70 MPa and impact toughness of 8.9 kJ/m^2).The surface bonding strength of the veneered jute fiber/PF composite decreased with the increase of jute fiber content,and the surface bonding strength of all groups were greater than 0.6 MPa,meeting the requirement of the national standard of China.The length of the immersion peeling test was less than 25 mm,which also meet the requirement of the national standard.As the resin content decreased,the peeling length of the resin layer increased.This indicated that the water resistance of the veneer was closely related to the resin content in the substrate,as the high resin content in the substrate provided a sufficiently thick adhesive layer for the bonded veneer.The observation of the scanning electronic microscope showed that the more fibers,the more pores in the unfilled cell cavities,the better the impact performance was obtained.The bonding interface between the resin and the fiber did not create voids,which ensured that the bonding interface effectively transferred the load,thereby increased the impact strength of the composite.There was a crack between the veneer and the jute fiber/PF composite substrate,and the interface between the surface layer and the substrate was not as good as the veneer when the resin content was high,which helped absorb the impact energy,but provided a channel for deep penetration of moisture,thus reducing the surface bond strength.The resin was not completely filled in fiber cell lumen,which benefited the impact properties and reduced the density of jute fiber/PF composite.Jute fiber is an abundant natural resource with low cost,and can be used to produce the composite with good performance.When jute fiber/PF composite was covered with wood veneer,the one-step veneer molding enabled partial PF resin to penetrate into the veneer,therefore its mechanical properties were significantly improved and the appearance of the panel could be beautified.