Research On The Preparation And Properties Of VGNF/Jute/EP Composites

Fiber reinforced composite materials have many excellent properties, have been widely used in industry, agriculture and civil fields. With recent awareness of environmental protection and enhancement of sustainable development, natural fiber composites attracted wider attention. Jute is annually regenerative, being low density, high strength and low price, it is very beneficial to be used as reinforeing fiber in composite industry for the decrease of cost and reduce the energy consumption of the production process. However, at this stage, there is a big gap between natural fiber composites mechanical properties and the mechanical properties of synthetic composite materials, for example, tensile strength and flexural strength. The rise of nanotechnology and applications give an effective solution for high-performance composite materials design and development provides. Carbon nano-fiber has excellent mechanical properties and unique microstructure, great aspect ratio and surface area, which is expected to become the ideal reinforcement for advanced composite materials.In this study, hand lay-up compression molding was used, surface modification of jute fibers and the method of increase dispersed of VGNF in the epoxy resin was studied. Jute fiber content and length, surface modification effect on jute epoxy composites mechanical properties was studied. In addition, the VGNF/jute/EP composite was prepared, modification time and the fiber content on properties of composite materials was studied. Structure and properties of materials were tested and characterized by SEM, X-ray diffraction, electronic universal testing machine and other equipment, and analyzed the microscopic structure and properties of relations.In order to research the addition of jute fiber effect on mechanical properties of epoxy resin, retted and carded jute fiber as reinforced fiber, respectively, according to different fiber length and content added to the epoxy resin to make composite material. The results showed: the incorporation of jute fiber on the epoxy resin mechanical properties significantly improved, and the fiber content and length on the mechanical properties of epoxy composite materials have a significant impact. With the increase of fiber content and length, flexural and tensile strength was first increased and then decreased. When jute fiber length 10 mm, the mass fraction of 20% to 30%, the tensile and bending of the Jute/Epoxy composite have a better overall performance. The increase of fiber content and fiber length increases the material modulus enhancement is beneficial. As the fiber content and fiber length increases, the material modulus was increasing. When the fiber content of more than 30%, fiber length of more than 10 mm, the increase was not obvious.In an attempt to further improve the Jute/Epoxy composites mechanical properties, jute fibers were treated by alkali treatment, silane coupling agent KH560 treatment, titanium coupling agent NDZ201 treatment, mild acetylation, cyanoethylation, the results show that: jute fiber mats after different treatments, the crystal of cellulose did not change. Due to the swelling effect of the alkali treatment, the introduction of outside groups by coupling agent and the chemical reaction of hydroxyl, so the fiber has a crystallinity index decreased, indicating that part of the crystalline region has been transformed into amorphous structure, which will effectively improve the interface between jute fiber and epoxy resin compatibility. The jute mat after five treatment, the mechanical properties of composite materials have improved to varying degrees, after alkali treatment and after treatment cyanoethyl, the epoxy resin composite material more significant increase of tensile strength, respectively, the sample increased 60.5% and 56.6% than the untreated; Silane coupling agent KH560 and alkali treatment on the bending strength of composites increase was more obvious than the untreated sample were 54.3% and 41.4% increase.To investigate the VGNF addition on mechanical properties of composite materials, first, The modification of VGNF was carried out on different time, then selected the best time of modification, added VGNF according to different content in the resin glue, made into VGNF/Jute/Epoxy composite materials. Experiments show that:modified VGNF powder can effectively remove impurities and make VGNF surface has —OH and —COOH functional groups, but too long modification time will lagrer chip spacing of VGNF, and destroy the mechanical Properties. Tensile properties and bending properties increased firstly and then decreases with increasing the content of the VGNF, the tensile strength and tensile modulus was higher 25.5% and 34.1%, bending strength and modulus increased by 27.2% and 16.1% than Jute/Epoxy composites without VGNF. The impact strength increases with increasing content VGNF, when the VGNF content is 1.2%, the impact strength higher 109.1% than without VGNF.The carbon nanofibers used in the jute/epoxy materials, hemp fiber can significantly improve the mechanical properties of composites, so linen is to develop high-performance fiber composite materials is an effective way, it is worth further study and discussion.