Effect of CNT-based resin modification on the mechanical properties of polymer composites

In this study an attempt was made to explore the possibility of substituting 3D E-glass fabric with eco-friendly basalt fabric along with the modification of resin using MWCNTs, a material system about which very limited information exists. The study involved comparing the mechanical properties of two sets of composites. The first set was comprised of 3D orthogonally woven E-glass-reinforced epoxy composites, basalt-reinforced epoxy composites, and hybrid 3D E-glass orthogonally woven/basalt-reinforced epoxy composites while the second set of composites was the same as the first but prepared with resin modified with Multi Walled Carbon Nanotubes (MWCNTs). All the composites were fabricated by hand lay-up and compression molding techniques. To modify the resin for the second set of composites, MWCNTs were dispersed into the epoxy resin with acetone as a surfactant by magnetic stirring and ultra-sonification. Mechanical tests included tensile, flexural, and low velocity impact strength which were evaluated as per standards. Scanning electron microscopy (SEM) was employed to study the fractured surfaces. Results showed that resin modification did not yield any positive results on the mechanical properties of the composites. The highest tensile (364.4 MPa) and flexural strength (345.3 MPa) was obtained for 3D E-glass composites followed by basalt composites and hybrid 3D E-glass/basalt composites while the highest impact strength of 198.42 kJ/m2 was exhibited by the hybrid 3D E-glass/basalt composites. SEM micrographs showed de-bonding between the modified matrix and fiber which was seen as one of the primary causes for relatively poor performance of the composites prepared with modified resin. Fiber breakage, matrix cracking, fiber pull-out, and delamination were the other modes of failure. Results suggest that hybridization with basalt fibers is a much safer, more cost effective, and eco-friendly option over resin modification

Influence of fabric orientation and compression factor on the mechanical properties of 3D E-glass reinforced epoxy composites

3-D E-glass fabric reinforced epoxy composites at 6 mm thickness were fabricated for various orientations of the binder yarn viz. 0°, 30°, 45°, 60° and 90° respectively. Tensile, flexural, interlaminar shear stress tests were conducted to ascertain the influence of binder yarn orientation on the mechanical properties of the composites. The composites with 0° binder yarn orientation showed the best strength followed by 90° whilst the others showed highly depleted traits in comparison. Shear stress induced at the interface of each lamina was seen as the major reason for drop in the strength. A secondary study was carried out to explore the effect of compression factor during fabrication on the mechanical properties of the composites. Laminates with varying thickness namely, 4 mm, 5 mm and 7 mm but, with same number of plies of 3D E-glass fabric at 0° orientation were fabricated. The test results were compared with the results of 6 mm composites from the primary study. The results showed that, compression factor affected the mechanical properties of the composites and had a direct relation with increasing compression factor up to a certain value beyond which a drop in properties was seen. Composites pressed to a thickness of 5 mm showed the best properties. Drop in properties was attributed to close packing of reinforcement and crushing of fibres leading to inefficient stress transfer. Scanning electron microscopy was employed to understand the modes of failure. The major failure modes observed were delamination, matrix cracking and debonding. Based on the results obtained, these composites can be seen as a material system for applications like ballistic armours, structural renovations and automobile components

Tensile and Flexural Properties of Chopped Strand E-glass Fibre Mat Reinforced CNSL-Epoxy Composites.

Glass fibres have the principal advantages such as high tensile strength, high chemical resistance, low cost, and excellent insulating properties which makes them an important constituent in fibre reinforced plastic and composite industry. In this study, E-glass fibre in the form of Chopped Strand Mat (CSM) with different weight fractions such as 15%, 30%, and 45% were used as reinforcement in CNSL-epoxy resin composites. Fabrication of the composites was done by hand layup technique. Micro-hardness, tensile and flexural properties were investigated for all the composite panels of different compositions. The results clearly indicated an improvement in micro hardness, tensile and flexural properties with the increase in fibre content

Tensile and Flexural Properties of Chopped Strand E-glass Fibre Mat Reinforced CNSL-Epoxy Composites.

Glass fibres have the principal advantages such as high tensile strength, high chemical resistance, low cost, and excellent insulating properties which makes them an important constituent in fibre reinforced plastic and composite industry. In this study, E-glass fibre in the form of Chopped Strand Mat (CSM) with different weight fractions such as 15%, 30%, and 45% were used as reinforcement in CNSL-epoxy resin composites. Fabrication of the composites was done by hand layup technique. Micro-hardness, tensile and flexural properties were investigated for all the composite panels of different compositions. The results clearly indicated an improvement in micro hardness, tensile and flexural properties with the increase in fibre content

Influence of TiO2 nanoparticle modification on the mechanical properties of basalt-reinforced epoxy composites

AbstractThis research work aims to experimentally evaluate the influence of resin modification using Titanium dioxide (TiO2) nanoparticles on the mechanical properties viz. flexural, tensile and Inter Laminar Shear Strength (ILSS) of basalt reinforced epoxy composites based on ASTM standards. The laminates were fabricated using a combination of hand lay-up and compression moulding techniques. Five different weight proportions of TiO2 nanoparticles were considered ranging from 1% to 5% with an increment of 1% by weight. To assess the quality of fabrication, void fractions were evaluated and were found to be in the range of 1.17% to 3.98%. The mechanical properties of TiO2 modified epoxy basalt composites were compared with composites without any TiO2 nanoparticles in it. The results indicated a significant improvement in the mechanical properties due to the addition of TiO2 nanoparticles. When compared to samples without TiO2, the highest mechanical properties were observed in samples having 4% TiO2 nanoparticles wherein an increase of around 60%, 40% and 70% was seen in flexural (526 MPa), tensile (420 MPa) and ILSS (30.6 MPa), respectively. A dip was observed in all the properties with further increase in nanoparticle content. Scanning electron microscopy (SEM) was carried out to analyse the fractured surface for dispersion of the nanoparticles and the failure mechanisms. SEM micrographs confirmed uniform dispersion of the nanoparticles while the major failure mechanisms observed were brittle fracture and fiber-matrix debonding. Results suggest that such composites can be used as a material in engineering applications wherein the loading is light to moderate

Effect of Hybridization on the Mechanical Properties of Chopped Strand Mat/Pineapple Leaf Fibre Reinforced Polyester Composites

Hybridization of synthetic and natural fibres as reinforcement makes the polymer composites environmental friendly and sustainable when compared to synthetic fibres based polymer composites. In this study chopped strand mat/pineapple leaf fibres were hybridized. Four laminates with six layers each, with different stack sequence (GGGGGG, GPPPPG, PGGGGP and PPPPPP) were fabricated using hand layup technique while maintaining a fibre to matrix ratio of 30:70 by weight with polyester resin as matrix. Mechanical properties such as tensile and flexural strength were determined and morphology of fractured specimens was studied. Maximum tensile strength of 180 MPa was obtained for the laminate with six layers of chopped strand mat followed by hybrid laminate with four layers of chopped strand mat at the centre (120 MPa). Tensile strength of hybrid laminate with four layers of pineapple leaf fibres at the centre was in third position at 86 MPa. Least tensile strength of 65 MPa was obtained for the laminate with six layers of pineapple leaf fibres. Similar trend was observed in case of flexural behaviour of the laminates with maximum flexural strength of 255 MPa and minimum flexural strength 107 MPa. Scanning electron microscopy of the fractured specimen reinforced with chopped strand mat only, indicated, fibre pull out, matrix cracking and lack of matrix adhesion to fibres. In case of hybrid composite (GPPPPG and PGGGGP) delamination was observed to be prominent due to improper wetting of the pineapple leaf fibres with the matrix. More significant delamination led to lesser strength in case of pineapple fibres reinforced composites even though the fibre pull out was relatively less

Effect of Hybridization on the Mechanical Properties of Chopped Strand Mat/Pineapple Leaf Fibre Reinforced Polyester Composites

Hybridization of synthetic and natural fibres as reinforcement makes the polymer composites environmental friendly and sustainable when compared to synthetic fibres based polymer composites. In this study chopped strand mat/pineapple leaf fibres were hybridized. Four laminates with six layers each, with different stack sequence (GGGGGG, GPPPPG, PGGGGP and PPPPPP) were fabricated using hand layup technique while maintaining a fibre to matrix ratio of 30:70 by weight with polyester resin as matrix. Mechanical properties such as tensile and flexural strength were determined and morphology of fractured specimens was studied. Maximum tensile strength of 180 MPa was obtained for the laminate with six layers of chopped strand mat followed by hybrid laminate with four layers of chopped strand mat at the centre (120 MPa). Tensile strength of hybrid laminate with four layers of pineapple leaf fibres at the centre was in third position at 86 MPa. Least tensile strength of 65 MPa was obtained for the laminate with six layers of pineapple leaf fibres. Similar trend was observed in case of flexural behaviour of the laminates with maximum flexural strength of 255 MPa and minimum flexural strength 107 MPa. Scanning electron microscopy of the fractured specimen reinforced with chopped strand mat only, indicated, fibre pull out, matrix cracking and lack of matrix adhesion to fibres. In case of hybrid composite (GPPPPG and PGGGGP) delamination was observed to be prominent due to improper wetting of the pineapple leaf fibres with the matrix. More significant delamination led to lesser strength in case of pineapple fibres reinforced composites even though the fibre pull out was relatively less

Experimental investigation into mechanical properties of coconut shell powder modified epoxy/ 3d E-glass composites

The aim of this research work was to investigate the influence of resin modification with Coconut Shell Powder (CSP) on the tensile, flexural and impact properties of composites reinforced with 3D E-glass orthogonally woven fabric. The composites were fabricated using a combination of hand lay-up and press moulding techniques. Three different proportion of CSP namely, 0.5%, 1.5% and 3% by weight of resin were considered for modifying the epoxy resin. The properties of these composites were determined and compared with composites fabricated without coconut shell powder. Additionally, to ascertain the effect of dispersion technique on the mechanical properties of the composites, their tensile strengths were compared with composites fabricated with epoxy in which CSP was added to the resin and mixed mechanically. Improved mechanical properties were obtained for composites fabricated with modified resin and an increasing trend was observed with increase in proportion of CSP with the highest properties obtained for composites with 3% CSP content showing an increase of about 117%, 87% and 39% in tensile, flexural and impact strengths respectively over the composites without CSP. Tensile strengths of composites prepared by mechanical dispersion of CSP were lower than the resin modified composites having the same CSP content, showing a drop of about 53% and 25% thereby proving the efficacy of resin modification process. Scanning Electron Microscopy (SEM) was employed to analyse the characteristics of the CSP and to investigate the various failure modes