Abstract
Postconsumer PET bottles including water and softโdrink bottles were depolymerized by glycolysis in excess glycols, such as ethylene glycol, propylene glycol, and diethylene glycol, in the presence of a zinc acetate catalyst. The obtained glycolyzed products were reacted with maleic anhydride and mixed with a styrene monomer to prepare unsaturated polyester (UPE) resins. These resins were cured using methyl ethyl ketone peroxide (MEKPO) as an initiator and cobalt octoate as an accelerator. The physical and mechanical properties of the cured samples were investigated. It was found that the type of glycol used in glycolysis had a significant effect on the characteristics of the uncured and cured UPE resins. Uncured EGโbased UPE resin was a soft solid at room temperature, whereas uncured PGโ and DEGโbased resins were viscous liquids. In the case of the cured resins, the EGโbased product exhibited characteristics of a hard and brittle plastic, while the PGโbased product did not. The DEGโbased product exhibited characteristics of hard and brittle plastic after strainโinduced crystallization had occurred. In addition, it was also found that no separation of the type of bottles was needed before glycolysis, since UPE resins prepared from water bottles, softโdrink bottles, and a mixture of both bottles showed the same characteristics. ยฉ 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 788โ792, 2003