Curing study of orthophtalic polyester resin: Effect on the degradation in saline environment (Spanish text)

Nowadays, composite materials based on a polymeric matrix are widely used in structural applications as engineering materials which offer high performances in advanced industrial sectors such as aerospace, aeronautical, transport, construction, etc. They can provide excellent mechanical and chemical properties, good chemical and weather resistance and low cost. Unsaturated polyester is one of the most used thermoset as a matrix for glass fibre reinforcements because of its good relationship properties/cost/quality, since it allows a more competitive cost.; Due to the importance that this type of materials reach in some industrial sectors, it is important the mechanical behaviour evaluation as one of the priorities in practically any of their applications; also, it is important to keep in mind that most of industrial sectors that use this resin are subjected to extreme environmental conditions that can produce degradation in the material and therefore, chemical resistance of composites becomes a critical characteristic in those applications that require a contact with environmental agents that can induce some degradation processes and, consequently, a substantial change on general performance.; The present study is focussed in the analysis of the effect of curing reaction of the thermosetting matrix of unsaturated orthophtalic polyester in the long term behaviour of materials made up of this type of matrix and glass fibre reinforcement. This is to determine the optimum processing conditions and its behaviour in an aggressive environment, concretely, marine environment.; Considering this, crosslinking level of the resin is a decisive parameter, since we can expect lower saline water absorption for high crosslinking levels. The optimum processing conditions are those that permit to obtain the highest crosslinking level in the unsaturated polyester internal structure. Since the degradation effect is related to the crosslinking level of the internal structure, with the optimum cured state conditions the loss of mechanical performance due to degradation is minimum, and therefore the resin shows the maximum quality to reach specifications required in its industrial service.