PET Recycling by Alcoholysis Using a New Heterogeneous Catalyst: Study and its Use in Polyurethane Adhesives Preparation

Abstract

One of the most used plastics in the world is poly(ethylene terephthalate), PET, which is on the top of the list of recyclable polymers. In this work, it was studied the chemical recycling of PET by the alcoholysis reaction using diethylene glycol (DEG) and sodium metasilicate (NaMs) as catalyst. This catalyst was not used before for this kind of reaction and showed an activity as good as the most used compound (zinc acetate). The PET‐polyol was produced with the reaction conditions that showed the higher weight yield and the final product was used in polyurethane (PU) adhesives compositions. The PUs were obtained using PET‐polyol, tolylene diisocyanate (10, 20 or 30% NCOfree) and DEG as chain extender or glycerin (GLY) as crosslinker. The adhesives were poured into Pinus taeda wood and the speciments were taken into mechanical properties evaluation accordingly to ASTM D 2339‐98. The results indicated that the PU adhesives 10% NCOfree with DEG were able to support the highest shear stress force applied (7.5 Mpa).

Chemical recycling ofPET: A stepping‐stone toward sustainability

“…Taking advantage of the possibilities to attain materials with diverse properties via modifying reaction pivotal parameters such as temperature, pressure, catalyst, alcohol type, etc, alcoholysis roles play as a reliable recycling method. 28 Albeit the use of various types of alcohols similar to ethanol, butanol, isooctyl alcohol, and trimethylolpropane has been reported approximately, to the best of our knowledge, more attention has been drawn toward methanolysis over recent years. Rubens et al investigated the chemical recycling of PET based on supercritical ethanol (T = 528 K and P = 7.6-11.6 MPa) in the presence of water.…”

“…Alcoholysis involves the degradation of PET in an alcoholic medium under high temperature and pressure circumstances. Taking advantage of the possibilities to attain materials with diverse properties via modifying reaction pivotal parameters such as temperature, pressure, catalyst, alcohol type, etc, alcoholysis roles play as a reliable recycling method 28 …”

Chemical recycling of polyesters

“…A separate category of catalysts that can be quite easily regenerated and used repeatedly in glycolysis of polyesters are some heterogeneous systems including: polyoxometalates [121], sodium metasilicate [122], metal oxides (e.g. derivatives of Zn, Mn, Fe, Ca, Ba, Sr) used directly or supported on nano-and microsilica particles [57,118], double metal hydroxides with a layered structure [123,124] /TiO 2 ) and zeolites [57,118].…”

Recent Studies on Recycled PET Fibers: Production and Applications: a Review

“…Generally, there are two methods for PET recycling: mechanical and chemical. In general, in the chemical method (16% of recycling), the reverse of the polymerization reaction, i.e., depolymerization, occurs and the primary monomers are obtained (Al-Sabagh et al 2016;Scremin et al 2019;Dębowski et al 2019). Chemical recycling is less used because it causes destructive changes in properties such as mechanical, thermal, and electrical conductivity (El Essawy et al 2017).…”