Abstract:
PET-products from post-consumer soft-drink bottles and 100% polyester fabrics were depolymerized by glycolysis reaction with the excess of propylene glycol at 1900 ℃ in the presence of zinc acetate as a catalyst. It was found that the glycolyzed products from bottles and fabrics possessed comparable molecular weight of 328 and 337 g⋅mol-1 , respectively. This was closed to the molecular weight of the theoretical glycolyzed product. The glycolyzed products were reacted with maleic anhydride and saturated acids that are succinic acid and adipic acid. The obtained unsaturated polyester or UPEs were then mixed with styrene monomer. Polyester resins products were casted into specimens by crosslinking reaction using methyl ethyl ketone peroxide and cobalt octoate as an initiator and a catalyst, respectively. Physical properties including hardness, impact strength, flexural properties and thermal properties of the cured products were tested. The results showed that the duration after gel time until cure time was the same for all resins. When the amount of saturated acids increased, the gel time and the cure time increased and the hardness decreased due to the decreasing amount of crosslinking sites. While the extended distance between crosslinking sites on molecular chains facilitated load distribution, resulting in the significant improvement of impact strength. The flexural strength was also improved when the small amount of saturated acid was used. It was found that the onset degradation temperature of the prepared resins were similar for all resins, as well as the glass transition temperature.