Interface Performance Of Fiber Reinforced Itaconic Acid Based Bio-Epoxy Resin Composite

Increasing environmental pressure and market demand promote the application of biomass source resin matrix in composite materials. This thesis has applied a new itaconic acid based bio-epoxy resin (EIA) with excellent mechanical properties as the matrix and studied the interfacial properties of fiber reinforced EIA composites. The main work of this thesis is as follows:1. EIA was used as the matrix of hemp fiber (HF) composite, the hemp fibers were surface treated by sodium hydroxide solution to improve the interface property of the composite. The results showed that alkali treatment removed hemicellulose and lignin compounds from the fiber surface, which resulted in the decrease of hydrophilic characterization and the increase of surface roughness and chemical activity of the fibers. Compared with the untreated HF/EIA composites, the alkali treated ones showed much improved mechanical and interfacial properties due to the enhanced interfacial adhesion between hemp fibers and EIA matrix. Moreover, both the alkali treated and untreated HF/EIA composites displayed more superior flexural properties and impact resistance than other reported bio-based thermoset composites, showing a promising application of EIA as matrix for green composites.2. EIA was used as the matrix of T800 carbon fiber(T800) reinforced bio based epoxy resin composites, the T800 fibers were surface deposited by using nano materials, cellulose nanofibers(NFC) and nanocrystalline cellulose (NCC) to enhance the interfacial properties of the composites. The interfacial properties of T800/EIA composites were studied by using the interlaminar shear strength(ILSS), dynamic mechanical thermal performance(DMTA), scanning electron microscopy(SEM). Results showed that T800/EIA had an ILSS of 85 MPa as well as a good interface adhesion, indicading a excellent interfacial property between EIA and T800 fiber. Surface modificated NFC and NCC both had high aspect ratio and a large amount of surface hydroxyl and carboxyl groups, when deposited on the T800 surface, they couled increase the physical contact and the chemical interaction between fibers and EIA matrix to improve the interface bonding. The DMTA indicated a better interfacial structure forming with T800-NFC/EIA and T800-NCC/EIA composites, which improved the interfacial properties of the composites and increased ILSS to 100MPa(NFC) and 95MPa(NCC), respectively. Among them, NFC with a relatively higher aspect ratio had a better interface reinforcing effect. The improved interface structure of the composites interface could effectively transfer stress, so that the bending strength and modulus of T800/EIA composites were improved.