Preparation And Performance Control Of Basalt Fiber Reinforced Polylactic Acid Green Composite

With the rapid development of society and the continuous improvement of living standards,people are paying more and more attention to environmental protection.As an environmentally friendly material with excellent performance,polylactic acid has always been loved by people,but its use range is limited due to its own performance factors.In order to expand its use range,a simple and effective method is to add fillers.The basalt fiber is made from natural rock,with excellent performance and environmental protection,but its interface performance with the polymer is poor.In this paper,a binary composite material with polylactic acid as the substrate and basalt fiber as the reinforcing material was prepared by hot pressing after solution mixing,and its performance was tested.The main research contents of the paper are as follows:(1)In order to improve the mutual performance of the interface between the basalt fiber and the polylactic acid substrate,the surface of the basalt fiber is first pretreated.In this paper,three methods of ultrasonic treatment,acid etching and alkaline etching are used.After 1.5 hours of ultrasonic treatment of basalt fiber,the surface impurities can be removed,and the non-smooth surface can still be observed.After etched with 3 mol/L hydrochloric acid solution for 1-12 h,the fiber surface gradually became smooth,and the surface was the smoothest when etched for 6 h.Continue to etch the fiber to show the rough surface again.After etching with 3 mol/L sodium hydroxide solution for 1-12 h,the fiber surface becomes rougher,and even the fiber skeleton structure is destroyed,and grooves appear.(2)In this work,basalt fiber assembled with in-situ SiO2 nanoparticles on the surface was successfully prepared via hydrothermal method and it was further treated with coupling agent KH-550 to improve interfacial interaction between PLA and BF.(3)It was demonstrated that the introduction of BFS could increase the crystallization of PLA and resulted in forming trans-crystallization based on TG and DSC results.The tensile strength of PLA/BF composites increased with the fiber content increasing from 1 wt%to 10 wt%.Furthermore,the interfacial interaction could be effectively improved by assembling SiO2(especially with 250 nm SiO2)onto the basalt fiber surface to form mechanical locking,which could keep the PLA matrix in place during the mechanical deformation.Therefore,an efficient enhancement of mechanical performance was achieved and this concept of assembling in-situ SiO2 on silica-based fiber as a modifier was a novel and simple approach to tailor the interfacial structure and properties of the polymer composites.