不同改性方法对竹塑复合材料拉伸性能的影响

研究了纳米碳酸钙浸渍改性对单根竹纤维表面碳酸钙附着情况、拉伸性能以及竹纤维/聚丙烯复合材料拉伸性能的影响,并将改性效果与纳米碳酸钙原位沉积改性进行对比。结果表明,纳米碳酸钙浸渍改性可以使碳酸钙颗粒均匀填充竹纤维表面微孔、褶皱等缺陷部位,附着的碳酸钙颗粒粒径均匀,分散性较好,附着量达到21.39%。经浸渍改性的单根竹纤维力学性能有所提高,拉伸强度、弹性模量、断裂伸长率分别提高了15.98%、22.15%和5.21%,但提高幅度低于原位沉积改性。分别将纳米碳酸钙浸渍、原位沉积改性竹纤维与聚丙烯薄膜制成竹塑复合材料,通过断面形貌观察发现两种改性方法均可改善竹纤维与聚丙烯的界面结合性能,复合材料拉伸性能相应提高,浸渍改性使复合材料拉伸强度和弹性模量分别提高了6.95%和15.80%,原位沉积改性分别提高18.68%和25.41%。虽然浸渍改性效果低于原位沉积改性,但工艺更简单。

Effects of different modifying treatments on tensile properties of bamboo-plastic composites

The objective of this research was to investigate the influence of bamboo fibers modified by impregnating with CaCO₃ nanoparticles on the adsorption situation of CaCO₃ particles and tensile properties of individual bamboo fiber as well as its composites. Effects of impregnated modification and in situ modification were compared. The results indicated that impregnated modification could make CaCO₃ particles which were good dispersion with uniform size fill the micropore and fold of the bamboo fibers to reduce manufacture defect. CaCO₃ loading reached 21.39%, tensile strength, modulus of elasticity and elongation of impregnated modified individual bamboo fiber increased significantly by 15.98%, 22.15% and 5.21%, respectively, but were below tensile properties of in situ modified fiber. By inspect and analysis to fracture morphology, the interfacial compatibility of composites which made from modified bamboo fiber and polypropylene film were improved. Tensile properties of the composites were enhanced accordingly. The tensile strength and tensile modulus of the composites reinforced with impregnated fibers increased by 6.95% and 15.80%, respectively, while the composites reinforced with in situ deposited CaCO₃ increased by 18.68% and 25.41%, compared to those reinforced with untreated fibers. In situ modification showed better improvement of mechanical properties both of individual bamboo fiber and composites. The process of impregnated modification was much easier.