不同增韧剂对PLA/稻壳木塑复合材料力学性能影响

以PLA、稻壳粉为原材料,分别加入玻璃纤维、乙烯-辛烯共聚物(POE)、碳酸钙为增韧剂进行增韧改性,以模压成型的方法制备了PLA/稻壳木塑复合材料,结合力学性能、吸水性能、X射线衍射(XRD)分析和对材料表面的显微观察研究了不同种类及含量的增韧剂对木塑复合材料力学性能的影响。结果表明,在玻璃纤维含量为20%的时候,PLA/稻壳木塑复合材料的增韧效果较好,其洛氏硬度值达68,其拉伸强度达到6.16 MPa,弯曲强度达到15.41 MPa,冲击强度为144.40 kJ/m2,但吸水性能显著提高,约为不添加增韧剂时的1.5倍;在POE含量为20%的时候,PLA/稻壳木塑复合材料吸水性降低效果最为显著,60 h浸泡实验其吸水率比不添加POE小10%。XRD分析及显微分析表明,除CaCO3自身结构影响外,添加不同增韧剂均未使PLA/稻壳复合材料形成新的晶型结构,加入POE和CaCO3的增韧效果不明显,是因为两种物质颗粒孤立存在于基体中,未形成相互搭连的网格结构。

Effects of different toughening agents on mechanical properties of PLA/rice husk wood-plastic composites

Using PLA and rice hull powder as raw materials,glass fiber,polyolefin elastome(POE),and calcium carbonate were added as toughening agents for toughening and modification.PLA/rice hull wood-plastic composites were prepared by compression molding,combining mechanical properties and water absorption properties.X-ray diffraction(XRD)analysis and microscopic observation of the surface of the material have studied the effects of different types and contents of tougheners on the mechanical properties of wood-plastic composites.The results show that when the glass fiber content is 20%,the toughening effect of PLA/rice husk wood-plastic composites is better.Its Rockwell hardness value is 68,its tensile strength is 6.16 MPa,and its bending strength is 15.41 MPa.The impact strength is 144.40 kJ/m2,but the water absorption performance is significantly improved,about 1.5 times when no toughener is added.When POE content is 20%,the water absorption reduction effect of PLA/rice husk wood plastic composites is the most.Significantly,its water absorption is 10%lower than without POE in the 60 h immersion test.XRD analysis and microscopic analysis show that apart from the influence of CaCO3’s structure,the addition of different toughening agents does not make PLA/rice hull composites form a new crystal structure.The material particles exist in the matrix in isolation,and no overlapping grid structure is formed.