Preparation And Properties Of Oil-flax Fiber Polymer Composites

In recent years,with the continuous improvement of social living standards,environmental pollution and Energy crisis not only affect the current ecological environment,but also bring serious harm to human health.Therefore,in order to fundamentally solve this type of problem,there is an urgent need for a green,renewable,and biodegradable new product to replace traditional processes in production and recycling.Some new types of plant fiber reinforced composite materials are constantly emerging and showing good application prospects.Among many plant fibers,oil-flax fiber has the characteristics of wide source,renewable,degradable,and excellent mechanical properties,which has attracted widespread attention from domestic and foreign researchers.In this project,the non-woven fabric was prepared by thermal bonding method,and the composite specimens were prepared by laminated lay-up and hot press molding method,using oil-flax and ES fibers as the reinforcement and polylactic(hereinafter referred to as PLA)as the matrix.Firstly,the surface of oil-flax fiber was modified by alkali treatment,microwave-assisted alkali treatment,microwave-assisted alkali treatment + silane coupling agent to enhance the interfacial bonding ability with the matrix,and the change of surface morphology and chemical composition of oil-flax fiber after modification was studied,and analyze the changes in fiber strength before and after modification through single fiber drawing experiments;Secondly,the content ratio of oil-flax fiber to ES fiber was studied to obtain the best oil-flax fiber non-woven fabric,and the effect of flame retardants on the strength and flame retardancy of the non-woven fabric was studied;In addition,PLA sheets were prepared and composite materials were prepared.Testing the mechanical properties,sound absorption performance,and formaldehyde content of oil-flax non-woven fabric reinforced composite materials with different modification methods after molding.The conclusions are as follows.1.It was found that each treatment method did not cause serious damage to the tensile strength of the fiber,and all of them reacted with the fiber to form new bonds,among which the microwave-assisted alkali treatment + silane coupling agent treatment modification method was optimal.After modification,the fiber tensile strength was the highest,reaching 203.38 MPa,compared with the untreated fiber,the tensile strength increased by 58.33%,and a uniform coupling agent film was formed on the surface of the fiber,and the characterization analysis showed that the silane coupling agent formed new chemical bonds on the surface of the fiber after hydrolysis,which improved the thermal stability of the fiber,and the crystallinity of the modified oil-flax fiber was reduced.2.When the modified oil-flax fiber and ES fiber are mixed in a ratio of 5:5,the synthesized oil-flax fiber non-woven fabric has the best comprehensive properties,with a breaking strength of 1169.84 N and a bursting strength of 1409.31 N.The ratio of flame retardant to water at 5:5 is selected for flame retardant treatment,which reduces the sustained combustion time,smoldering time,damage length,and mechanical properties of nonwoven fabrics.The flame retardant treatment improves the thermal stability and charring ability of the fabric.3.After microwave assisted alkali treatment+silane coupling agent modification,the non-woven fabric was prepared by thermal bonding with ES fiber in a ratio of 5:5.The oil-flax non-woven fabric reinforced composite after hot pressing of laminated layers had high mechanical properties,and its tensile properties,bending properties and compression properties were 33.78 MPa,39.91 MPa and 69.29 MPa,respectively.The maximum energy absorbed during impact was 29.66 J.In addition,the sound absorption coefficient increases,the formaldehyde content decreases sharply,and the mechanical and application properties of the composite material are significantly improved.The aim is to improve the performance of green composite materials in building materials,thereby expanding the range of use of degradable materials and fibers,and providing practical guidance for solving the current environmental pollution and energy consumption problems in China.