Preparation And Properties Of Jute Fiber/Polypropylene Composites

The efficient resource utilization of plant fiber is an important part of the construction of national ecological civilization.Plant fiber reinforced composite materials are receiving extensive attention from the industry and society because of their good practicability,green environmental protection and recyclability.As a relatively low-priced plant fiber among the hemp fibers,jute fiber has a wide range of sources and excellent mechanical properties,but the compatibility of jute fiber and polymer is poor,which affects the comprehensive application performance of composite materials.The basic research of jute fiber Fiber properties,modification methods and preparation of environmentally friendly jute fiber reinforced resin matrix composites have important practical significance.In this paper,jute fiber(JF)and polypropylene(PP)were used as raw materials to prepare JF/PP composites by melt blending and injection molding.Based on the morphological characteristics of JF,the effects of the content of JF,the type and dosage of fillers and different biological enzymes on the mechanical properties,thermal stability,crystallization properties and water absorption properties of JF/PP composites were explored.Using Fourier Infrared Spectroscopy(FTTR)to analyze the changes in the chemical structure of JF before and after biological enzyme modification.The m icrostructure of JF surface and tensile fracture surface of JF/PP composites before and after modificalion were observed by high resolution scanning electron microscopy(SEM).The results of'the study found:(1)The morphological characteristics of JF were studied,and the influence of JF content on the comprehensive properties of composite materials was discussed.With the increase of JF content,the mechanical properties of JF/PP composites first increased and then decreased.The addition of JF reduced the thermal stability of the composite material and increased the crystallinity.SEM showed that after the JF content exceeded 10wt%,JF began to agglomerate in the composite material.The water absorption experiment results showed that the addition of JF made the water absorption rate of the composite material increased to a certain extent,and it increased with the increase of the amount of JF addition.When the JF content was 30 wt%,the overall performance of the JF/PP composite was the best.(2)The effects of three kinds of fillers on the properties of JF/PP composites were discussed.With the increase of filler content,the mechanical properties of JF/PP composites first increased and then decreased.When the filler content was 4 wt%,JF/PP composite materials mechanics performance was best,the tensile strength,flexural strength and flexural modulus of the composite material filled with wollastonite were increased by 23.5%,26.3%,and 44.6%,respectively,compared with the JF/PP composite material without filler.Fillers could improve the thermal stability of JF/PP composites.DSC analysis showed that the crystallinity of JF/PP composites increased after the addition of fillers.SEM analysis showed that a certain amount of filler was filled between JF and PP matrix,which reduced the porosity in the composite system.The water absorption experiment showed that the water absorption rate of the JF/PP composite material filled with the filler had a certain increase.Among them,JF/PP composites with wollastonite had the best properties.(3)JF was pretreated with different kinds of biological enzymes,and its influence on the comprehensive performance of JF/PP composite materials was studied.After JF was treated with biological enzymes,the surface of JF became rough and the surface structure changed.After the treatment of biological enzymes,JF/PP composite materials mechanics performance increase,and the water absorption rate slightly decreased.After biological enzyme treatment,the thermal stability and crystallinity of the JF/PP composite material were improved,and the tensile fracture hole of the JF/PP composite material was reduced.The mechanical properties of JF/PP composites treated with pectase were the best,and composite materials tensile strength,bending strength and bending modulus,respectively were 24.83 MPa,42.41 MPa and 2279.78 MPa,which were increased by 14.4%,17.1%and 24.0%compared with the unmodified composites,respectively.The thermal stability and crystallinity of the xylanase treated JF/PP comnosites were the highest,and the crystallinity of the composites reached 46.1%.