Synthesis of unsaturated polyester resin from postconsumer PET bottles: Effect of type of glycol on characteristics of unsaturated polyester resin

Abstract

Postconsumer PET bottles including water and soft-drink 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 EG-based UPE resin was a soft solid at room temperature, whereas uncured PG-and DEG-based resins were viscous liquids. In the case of the cured resins, the EG-based product exhibited characteristics of a hard and brittle plastic, while the PG-based product did not. The DEG-based product exhibited characteristics of hard and brittle plastic after strain-induced 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, soft-drink bottles, and a mixture of both bottles showed the same characteristics.

Degradation of Poly(ethyleneterephtalate) Waste to Obtain Oligomers Using a Zinc Complex as Catalyst

“…The hydroxyl values after glycolysis were 252.1 for the product obtained in Experiment 2 and 199.4 for the Experiment 3. The OH value reported of BHET is 441.5 and 251.3 for the dimer 30 . These results also suggest that the products obtained are mainly formed by oligomers instead pure BHET, dimers or trimers.…”

Investigation of Potentional Use of Recycled Poly(ethylene Terephthalate) in Polyurethane Synthesis

“…The glycolysis reaction is molecular degradation of PET polymer by glycols, in the presence of transesterification catalysts, mainly metal acetates [2], various chloride catalyst [3], and sodium sulfate [4]. The glycolysis products could be used for the synthesis of different resins, such as epoxy [5,6], unsaturated polyester resin [7,8,9], alkyd [10,11] or melamine formaldehyde resins [12].…”

Synthesis of Unsaturated Polyester Resins from PET Wastes: Effect of a Novel Co-catalytic System on Glycolysis and Polyesterification Reactions

“…Furthermore, synthesis of UPR from recycled PET can alleviate environment pollution. Therefore, the concept of preparing unsaturated polyester resin from the glycolyzed PET products is well developed [1][2][3][4][5][6][7][8].…”