Thermo-mechanical characterization of unsaturated polyester/glass fiber composites for recycling

Abstract

Unsaturated-polyester/glass-fiber composites are worldwide more and more used. Actually, their thermochemical and mechanical recycling paths are quite well-known. But, due to the relatively low value of the end products, these two paths are hardly economically viable. Thus, a third way will be proposed as a thermomechanical path. In order to recycle these composites, a study of their thermo-mechanical behaviors is proposed in this work, through various static and dynamic tests at temperatures ranging from ambient to 150°C, over their glass-transition-temperature (Tg). As expected, the results prove that unsaturated-polyester reinforced by woven glass-fibers is more resistant in static flexion and traction than composite made with mixed chopped and woven glass-fibers, at ambient temperature and up to 150°C. Also, static and dynamic tests have shown that composite manufactured by infusion is more resistant than the hand lay-up composite forming. Indeed, dynamic 3-points-flexural-bending test indicates that these composites lose their stiffness during the temperature rise. Furthermore, the composites ageing study shows the appearance of Mullins effect and hysteresis phenomena, at 150°C. After an accelerated ageing in distilled water at ambient temperature, the composite lost about 66% of its flexural resistance but a gain of 195% in its deformation at break is obtained. For an ageing in distilled water at temperature around its Tg, this composite lost the same ratio in its flexural resistance but got 180% in its yield deformation, compared to its virgin state. The mechanical properties lose can be interpreted by the ester function hydrolysis and the glass fibers damage.

Polyester-Based Coatings with a Metal Organic Framework: An Experimental Study for Corrosion Protection

“…Prolonging the reaction time at a specific temperature may negatively affect the molecular weight as it can lead to secondary reactions that reduce the weight. In industrial syntheses, it is often preferred to extend the reaction time rather than using a catalyst that could compromise the quality of the polyester [30][31][32][33]. Based on experimental data, it has been found that the reverse reactions in the esterification process can be ignored at temperatures below 180 • C and/or conversions lower than 95%.…”

Effect of Ageing on the Mechanical Performance of Thermoset Polymers: A Statistical Approach

“…The wide use of these polymers in tanks, tubes, vessels, outdoor applications and many other aggressive environments, makes it necessary to well understand their long-term stability in the presence of external factors that cause physical and mechanical degradation, such as temperature, oxygen, water, chemicals, radiations, etc [9,10]. In recent years, a large number of studies related to the physicalmechanical properties of epoxy and polyester matrix composites after ageing in different environments have been carried out [11][12][13][14][15][16][17]. However, the study of these neat polymers, which can have many other applications in addition to composite matrices, and the comparison of their properties after the ageing process through robust statistical analysis, is still very limited.…”