Composites of polyester + glass fiber residues vs. composites with mineral fillers

Polymer composites, such as those composed of a polyester, glass fibers (GFs), and mineral fillers (e.g. CaCO3), pose a threat to the environment because of the growing amount of residues and due to difficulties in their recycling. Therefore, we have studied effects of incorporation of (polyester + GFs) waste material as a filler into virgin composites. Two types of polyester + glass fiber composites were developed using hot compression molding, one of them with recycled (polyester + glass fiber) material obtained via knife or ball milling; the other, a control group, contained CaCO3, a traditional filler in this field. Dynamic friction and wear rate were determined using a pin-on-disk tribometer and a stylus profilometer, respectively. As expected, the presence of the residues significantly decreases dynamic friction and wear rate when compared to CaCO3, since the main constituent of the residues is a polymeric material. Thus, polyester + glass fiber composite residues are a candidate for a partial substitution of CaCO3. This should lower the environmental contamination caused by discarding the residues as well as provide composites with lower wear rates.