NATURAL FIBER REINFORCED HYBRID POLYMER COMPOSITES

Abstract

The improvement in mechanical properties of natural fiber can be done during preparation of composites, heat and alkali treatments to kenaf fibers were performed and effects on mechanical properties were investigated. Compared with other heat treatment temperatures, the tensile strength of kenaf fiber at 140℃ exhibited maximum value, which could be attributed to the increase of crystallinity index of fibers after heat treatment. This paper presents the finding of an experimental study on kenaf fibre hybrid composite plates for potential application in shear strengthening of RC beam. In the experimental programmer, hybrid composite plates had been fabricated using kenaf and carbon fibers with five different mixes i.e., 47% kenaf with 0% carbon; 45% kenaf with 2.5% carbon; 47% kenaf with 5% carbon; 45% kenaf with 7.5% carbon and 45% kenaf with 10% carbon. The physical and mechanical properties of the fabricated hybrid composite plates were then experimentally investigated. Results showed that carbon contents had an influence to enhance the tensile strength of the plates. Hybrid composite plate with 10% carbon content had shown 130% higher tensile strength as compared to that of plate without carbon fibre. The carbon content also had enhanced the modulus of elasticity of plates.

Specification

Description:The glass fiber (synthetic fiber) having good mechanical properties, but it's difficult in recycle, non- Biodegradable, relative high cost and difficult to breathe. The Kenaf fiber (natural fiber) having good mechanical and water absorption properties, easily accessible, cost effective, Biodegradable. The flax fiber (natural fiber) having good mechanical properties and easy to recycle, Biodegradable. This research investigated the performance of kenaf fiber unsaturated polyester composites. Different parameters which affect the mechanical, thermal, and dynamic properties were studied. Most of the investigations included experiments and analytical modeling if the problem was tractable.

Curing Behavior and Mechanical Properties of Unsaturated Polyester Resin
The physical parameters of unsaturated polyester resin such as viscosity and density decreased with the increase of environmental temperature and styrene (ST) concentration. The ST concentration controls the reactivity of the unsaturated polyester and also the crosslinking density of the final network.
Physical and Tensile Properties of the Kenaf Best Fiber
Natural fibers exhibit superior advantages over the synthetic fibers especially in cost, environmental aspects and high specific modulus compared to synthetic fibers. The physical and mechanical properties of the kenaf fiber were observed. The results found good agreement within the range in the literature.
Mechanical Properties of Composites
The mechanical properties of fiber reinforced composites are dependent upon the stability of the interfacial region. Thus, the characterization of the interface is of great importance. Alkali treatment increased the impurities of fiber surface and increased the interface between fiber and matrix, and also decreased the fiber pullout which enhanced tensile and flexural properties.

Impact test result shown the better improvement in treated sample than untreated sample. Different parameters affected the mechanical properties of natural fiber composites in this investigation, namely curing process, MEKP and ST concentrations, fiber weight fraction, fiber length and fiber treatment. SEM analysis showed that the interaction between the hybrid fibers and unsaturated polyester matrix was poor such that fiber de bonding, fiber pull-out, matrix fracture and fibers fracture occurred.
The experimental data of tensile results for kenaf composites was compared with several theoretical predictions and found to be in good agreement with some of these models.
Effects of Water Absorption on Mechanical Properties of Composites
The results of this part discussed the water absorption characteristics and environmental effects on tensile and flexural properties of fiber composites at different fiber contents, immersion times, and fabric pre-drying. Fiber weight fraction and temperature surrounding played a role in the rate of moisture uptake and overall uptake at saturated points of Kufic.
The tensile, flexural and impact properties of natural fiber composites were found to be dependent on the fiber length and fiber weight fraction. Water absorption patterns of these composites were found to follow fiction behavior. Values obtained for diffusion coefficients were in agreement with the range of values reported in the literature.

, Claims:The author claimed that,


1. Kenaf Composites (% of UP and % of ST)
Specimens from 10% to 40% weight percentage of fibers were fabricated to produce kenaf/unsaturated polyester composites (KFUPC) of various styrene concentrations. The prepared resin (60%UP+ 40%ST) and (50%UP+50%ST) + 1 vol% MEKP was blended to fiber size (1-6) mm to prepare 60KFUPC and 50KFUPC. In addition, the prepared resin (60%UP+40%ST) + 1% MEKP was blended to a fiber size of 10-30mm. the composite mixture was poured into the mold cavities.

2. Composite Curing Process
The composite was left to cure for about 24 hours at 25 % 2ºC. The specimens were ground to trim the flushes of resin during the fabrication process. Certain composite specimens were post cured in an oven for 5 hours at 60ºC.

3. Alkali Treatment
The presence of surface impurities on the untreated kenaf fiber surface is very obvious. The surface of the treated fiber seems rough when compared to the untreated fiber. Following 6% NaOH treatment, wax, oil and other surface impurities were removed and the treatment also roughened the surface of the fiber bundles.

4. Curing Behavior and Mechanical Properties of Unsaturated Polyester Resin
The physical parameters of unsaturated polyester resin such as viscosity and density decreased with the increase of environmental temperature and styrene (ST) concentration. The ST concentration controls the reactivity of the unsaturated polyester and also the crosslinking density of the final network.

5. Efficiency: Mechanical and water absorption properties of components can be improved by Natural fibre reinforced hybrid polymer

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