Effect of alkaline and acidic solutions on the tensile properties of glass–polyester pipes

Effects of alkaline and acid solutions on glass/epoxy composites

“…Finally, the discussion done before agrees with the literature [2,3] but disagree with reference [1] where was observed a decrease of the tensile properties for alkaline solutions and an increase of these properties with acid solutions.…”

“…Finally, the microstructure of the polyester degraded more under acid and higher temperature exposure as indicated by increased surface roughness, cracks and diffusion of sulphur into the cracks. On the other hand, Stamenovic et al [1] studied the effect of alkaline and acid solutions on the tensile properties of glass-polyester composites. They concluded that the alkaline solution decreases the tensile properties (ultimate tensile strength and modulus) and this tendency increases with the pH value.…”

“…Concerning the acid solutions, they increase the tensile properties and this tendency was more relevant when the pH value decreases. For both solutions, Stamenovic et al [1] concluded that the changes observed on the tensile properties are proportional with the exposure time (number of days in liquid). The effects of sulphuric acid concentration and the sequential layup of glass fibre reinforcements on the diffusion behaviour glass/epoxy laminates were studied by Pai et al [4].…”

“…The results showed that composite specimens with chopped strand mat as the skins layers exhibited higher weight gain than those with woven roving mat as the skin layers. Material degradation is more pronounced with the increase of sulphuric acid concentration, which can be explained by hydrolytic dissolving of the matrix in contact with this acid [1,4]. Degradation studies were carried out in different solvents like 10% NaOH, 1 N HCl and 10% NaCl by Sindhu et …”

“…In fact alkaline solutions are highly corrosives [1,21] and, according studies developed by Stamenovic et al [1], the influences of alkaline solution on mechanical properties increase with the pH value.…”