Physico-mechanical and morphological studies of jute/glass reinforced epoxy composites and its hybrids

Present research work emphasis on the fabrication and evaluation of the physico-mechanical performance of jute/glass fibre reinforced epoxy composites and their hybrids. Composite samples were fabricated by closed mold hand lay-up technique. Fibre/matrix interfacial adhesion of fractured specimens after mechanical tests was investigated using SEM (scanning electron microscope). Among J/Epoxy, G/Epoxy, J/G/Epoxy, J/G/Epoxy composites show the maximum Shore-D hardness value of 99 as compared to jute/epoxy and glass/epoxy of Shore-D hardness value of 96 and Hardness value of 98 Shore-D, respectively. Experimental studies have shown that there are superior Physico-mechanical properties of hybrid composites (jute/glass/epoxy).

The effect of oil palm trunk particles and composite density on the physical and mechanical properties of rigid polyurethane foam composite

The oil palm trunk (OPT) particle was used as a filler for the manufacture of rigid polyurethane foam composites (RPUFC). The purpose of this research is to investigate the effect of OPT particle content and variation of composite density on the physical and mechanical properties of RPUFC. The RPUFC was created with five different volume fractions of OPT particles (0, 2.5, 5, 7.5, 10 wt%) and three different composite densities (40, 50, 60 kg/m3). The OPT particles, polyols, and isocyanate were mixed, poured and formed in a closed mold. The moisture content (MC), water absorption (WA), compressive strength (CS), screw withdrawal (SW), and internal bonding strength (IB) properties were determined according to JIS A 5908-2003. The flexural strength (FS) properties were determined according to ASTM D790. The physical properties (MC, WA) were increased with increasing OPT particles in the RPUFC. The RPUFC with 2.5% OPT particle was higher in modulus of rupture, modulus of young and CS values compared to RPUFC control. The IB and SW values were increased when 2.5% OPT particles were added to RPUFC. The best PURFCs were produced with the addition of 2.5% particles at a density of 50 and 60 kg/m3.

INVESTIGATION OF PRESSING DIAGRAMS DURING MOLDING A MIXTURE OF COPPER POWDERS AND SILICON CARBIDE

Проведено исследование смеси порошков меди и карбида кремния после одностороннего холодного формования в закрытой пресс-форме методами: растровой электронной микроскопии, гидростатического взвешивания и анализа диаграмм прессования. Выявлены основные этапы формования, их границы и характерные процессы, происходящие на каждом из них. Установлено, что на диаграмме формования можно выделить не менее трёх областей. Показано, что их границы (по давлению) определяются механическими свойствами материалов используемых порошков и процессами перераспределения / укладки структурных элементов и их упругой/неупругой деформации. A study of a mixture of copper and silicon carbide powders after one-sided cold forming in a closed mold was carried out by methods: scanning electron microscopy, hydrostatic weighing and analysis of pressing diagrams. The main stages of molding, their boundaries and characteristic processes occurring at each of them are identified. It was found that at least three areas can be distinguished on the molding diagram. It is shown that their boundaries (in terms of pressure) are determined by the mechanical properties of the materials of the powders used and the processes of redistribution / packing of structural elements and their elastic / inelastic deformation.

Viabilities for obtaining, manufacturing and applying composites using bamboo powders and ophthalmic lens waste

The objective of this research was to obtain composites using petioles bamboo and ophthalmic lens waste powders and polyester resin. Such materials have no defined application, they are produced in large quantities and their waste is discarded irregularly in landfills. Bamboo and ophthalmic lens rejects powders were produced, with particle sizes of 2.07 mm and 1.14 mm, respectively. Preliminary tests were carried out to determine the maximum quantities of each material to be mixed with the polyester resin matrix, in order to guarantee the good processability of the new material produced. The mass quantities used were 10 and 15% bamboo, 15 and 40% tailings and a hybrid composition with 5% bamboo and 20% tailings, to obtain the desired composites. The composite plates were manufactured by the cold compression wet molding process in closed mold. Several tests were carried out to characterize the composites that were produced. It was found a decrease in the mechanical strength of the composite in comparison to the matrix, concluding that the bamboo powders and ophthalmic lens waste had a filling load function in the composites produced. The most expressive result of the composites was in the impact resistance, corresponding to 0.55 J/cm2 for OLWP 40% higher in 39.6% in relation to the polyester resin matrix. As a practical application, table and bench tops were manufactured with the most economically and ecologically viable composite, 40% OLWP.

Preparation of Glass Fabric/Poly(l-lactide) Composites by Thermoplastic Resin Transfer Molding

This study reports the first example of the production of polylactide composites prepared by Thermoplastic Resin Transfer Molding (T-RTM) via in situ bulk polymerization of l-lactide (l-LA) after injection in a closed mold containing glass fabrics. Tin octoate Sn(Oct)2 was used as the catalyst and first evaluated at the lab-scale in the experimental conditions required in the tank and in the mold of the RTM device. The reactions were then upscaled in the RTM in the absence of reinforcement to ensure the feasibility of the process (transfer and polymerization). Finally, poly-l-lactide (PLLA)-based composites with glass fabrics as the reinforcement were obtained. The resulting PLLA matrices exhibited conversions up to 99% along with high molar masses of up to 78,000 g·mol−1 when the polymerization was carried out under dynamic vacuum (vacuum-assisted RTM, VARTM). Moreover, a good impregnation of the glass fabrics by the matrix was observed by optical microscopy.

CaCO3 Particle-Filled Polymer Composite Manufacturing via RTM Process: An Experimental Investigation

Resin transfer molding (RTM) is one technique that has been used to produce polymer composites, which consists in injecting a thermoset pre-catalysed resin into a closed mold containing a dry fiber preform. In this sense, this study aims to investigate the effect of the calcium carbonate content (CaCO3) in the polyester resin during the RTM process. Several experiments were conducted using glass fiber mat molded in a RTM system with cavity dimensions 320 x 150 x 3.6 mm, at room temperature, and different injection pressure (0.75 bar) and CaCO3content (0, 10, 20, 30 and 40%). Results of the physical parameters such as viscosity, permeability, and mobility, and flow front position of the resin into the mold along the RTM process are presented and analyzed. From the results was concluded that the higher the injection pressure and lower CaCO3content into the resin, the lower filling time.

Effect of CaCO3 Content in Resin Transfer Molding Process

Composite material can be defined as a combination of two or more materials on a macroscale to form a useful material, often showing properties that none of the individual independent components shows. Resin Transfer Molding (RTM) is one of the most widely known composite manufacturing technique of the liquid molding family, being extensively studied and used to obtain advanced composite materials comprised of fibers embedded in a thermoset polymer matrix. This technique consists in injecting a resin pre-catalysed thermosetting in a closed mold containing a dry fiber preform, where the resin is impregnated. The aim of this study is to investigate the effect caused by the use of CaCO3filled resin on the characteristics of the RTM process. Several experiments were conducted using glass fiber mat and polyester resin molded in a RTM system with cavity dimensions of 320 x 150 x 3.6 mm, at room temperature, and different CaCO3content (0, 10, 20, 30 and 40% in weight). The results show that the use of filled resin with CaCO3influences the resin viscosity and the porous media permeability, making it difficult to fill the porous media during the molding process, however it is possible to make composite with a good quality and low cost.

Synthesis and Characterization of Polyurethane-Nanoclay Composites

In this study polyurethane (PUR)-nanoclay composites were synthesized using methylene diphenyl diisocyanate, polyol, and hectorite clay. The weight percentage of hectorite clay was varied at three different levels to study its effect on the properties of the thermoplastic polyurethane nanocomposite. The nanocomposite polyurethane foam was synthesized in a 2-step reaction process. The first step involved the addition and dispersion of nanoclay into the isocyanate. The mixture was then mixed with the polyol, and the foam was cast in a preheated closed mold. The PUR-nanocomposite foams were analyzed for cell structure, physical, mechanical, and thermal properties. The composite foam showed significant increase in tensile and flexural strengths, abrasion resistance, and thermal properties.