Influence of hollow glass microspheres on the mechanical and physical properties and cost of particle reinforced polymer composites

Abstract. The goal of the study was to find a cost-effective composition of a particle reinforced composite that is light in weight but has sufficient mechanical properties. The matrix of the particulate composite is unsaturated polyester resin that is reinforced with alumina trihydrate particles. Part of the alumina trihydrate proportion was replaced with hollow glass microspheres to reduce weight and save costs. In order to find out the influence of the light filler on the physical and mechanical properties of composites, materials with different percentages of the light filler were prepared. Test specimens were cut from moulded sheets that were fabricated with vacuum assisted extruder. Tensile strength, indentation hardness measured with a Barcol impressor, and density were determined. Based on the experimental data a multi-criteria optimization problem was formulated and solved to find the optimal design of the material. Artificial neural networks and a hybrid genetic algorithm were used. The optimal solution is given as a Pareto curve to represent the distinction between the density and selected mechanical properties of the composite material. The composite material filled with 6% hollow glass microspheres showed 3% loss in the tensile strength and 26% loss in the surface hardness compared to the composition without the filler. The weight decreased by 13% compared with the initial composition. The addition of hollow glass microspheres did not lower the net value of the material, it increased 7%

Preliminary Study of the Influence of Post Curing Parameters to the Particle Reinforced Composite's Mechanical and Physical Properties

This study examines the effect of different post cure parameters to a polymer matrix particulate reinforced composite material. The goal is to evaluate the importance of different factors and to suggest a well-balanced post cure mode that supports the application of the material.<br />Polymer matrix composites are post cured at elevated temperature to increase the amount of cross linking to achieve better chemical and heat resistance and mechanical properties. Every material has an individual post cure process that depends from the raw materials. Post curing variables include temperature, duration of cure, the time between initial curing and post curing and temperature profile gradient.<br />There are several ways to determine the cure state of a polymer. It can be evaluated based on the mechanical and physical properties, residual styrene content, glass transition temperature, residual exotherm or solvent swelling test.<br /> For the determination of the suitable post cure parameters test slabs were casted and post cured with varying time and temperature. Glass transition temperature, residual exotherm, softening in ethanol, surface hardness, flexural strength and flexural modulus were determined. It is shown that the material should be cured at 60°C–80°C. With higher temperature and extended time of cure the glass transition temperature raises but the material becomes too brittle.<p>DOI: <a href="http://dx.doi.org/10.5755/j01.ms.18.3.2435">http://dx.doi.org/10.5755/j01.ms.18.3.2435</a></p

Characterization of Disintegrator Milled Electronic Waste Powders for Materials Recovery

In this paper, the mechanical milling of the Printed Circuit Boards (PCB) was carried out. the new air classification stand was developed for testing the separation of lightweight particles like tinfoil stripes and plastics. the test results for separation of heavier fractions like non-ferrous metals (Al, Cu) are presented. For milled materials characterization the sieve analysis, laser diffraction analysis and a scanning electron microscope were used. the chemical composition of the PCB powders was studied by means of the energy dispersive X-ray microanalysis. Then, the pyrometallurgical recycling PCB was executed. the mechanisms of thermal degradation and combustion are investigated using TG/DTA and MS machines with the aim of separating and recovering the organic and metallic materials. the mass loss, conversion fraction with the temperature, activation energy etc. are investigated. Some alkalis, such as Na2CO3, NaHCO3, NaOH and CaCO3 were used to control the exhausted toxic gas such as HBr and benzene