Unsaturated polyester resins: blends, interpenetrating polymer networks, composites, and nanocomposites

Unsaturated polyester resins (UPRs) are the backbone of the composites industry, representing approximately three-quarters of the total resins used. Though they provide excellent properties such as chemical and weather resistance with relatively low cost, in general, the mechanical properties of polymers are inadequate for many structural purposes without the addition of the appropriate fibers as load carrying constituents of composites. In particular, the strength and stiffness of these polymers are significantly low compared to metals and ceramics. This means that there are considerable benefits to be gained by reinforcing polymers with suitable fibers and fillers. The addition of inorganic nanoparticles into polymers has been a popular technique to modify the properties of matrices. Hence, this chapter focuses on UPRs, their blends, and interpenetrating polymer networks toward the production of enhanced composites and nanocomposites for wider and sustainable engineering applications.