High performance alkyd resins synthesized from postconsumer PET bottles

Abstract

The glycolytic recycling of waste PET presents a challenge for the production of secondary value-added products, such as alkyd resins. A way to overcome unsatisfactory mechanical, drying and chemical resistance properties met with alkyds obtained from difunctional glycolyzates, was proposed. Waste PET was glycolyzed using multifunctional alcohols: glycerol (G), trimethylolethane (TME), trimethylolpropane (TMP) and pentaerythritol (PE), giving tetra-and hexa-functional glycolyzates and, for comparison, using diethylene glycol (DEG), propylene glycol (PG) and dipropylene glycol (DPG) giving di-functional glycolyzates. The obtained glycolyzates were examined by 1 H and 13 C NMR, FTIR spectroscopy and elemental analysis and further used in the synthesis of alkyd resins. The properties of the prepared alkyd resins (acid, hydroxyl and iodine values, color, average molar masses and molar mass distributions, viscosity, drying time, hardness, flexibility, gloss, adhesion and chemical resistance) were investigated with respect to the functionality and the structure of the used glycolyzates. Alkyd resins derived from multifunctional glycolyzates (TME and TMP) showed considerably enhanced properties compared to those produced from difunctional glycolyzates and also to conventional general purpose resins.Please do not adjust margins Please do not adjust margins decreased the branching degree. Future work on this matter will involve the preparation, analysis and application of lacquers, paints and anticorrosive coatings based on the presented alkyd resins.

Recent Advances in Environment-Friendly Alkyd Nanocomposites Towards “Greener” Coatings

“…The approach has multiple advantages: (i) value addition to a waste material (i.e., PET), (ii) reduction in the amount of waste PET in dumps and landfills, (iii) reduction in amount of phthalic anhydride, and (iv) improved performance of alkyd. The best performance was achieved by the inclusion of trimethylolethane and trimethylolpropane, as they had four sterically unhindered primary hydroxyl groups that produced alkyds with higher degree of branching, consequently higher molar mass, which led to improved mechanical, drying, and chemical resistance properties [34].…”

Synthesis of high-performance alkyd anticorrosion coatings based on waste poly(ethylene terephthalate)

“…The transesterification reactions of waste PET with TMP and DPG were performed in the presence of TBT catalysts, and the obtained hydroxylterminated products of glycolysis were characterized by determination of the hydroxyl (HV) and acid (AV) values and elemental analysis. During the trans-esterification, chain fragmentation occurs and the formation of the corresponding esters of terephthalic acid with used multifunctional and difunctional alcohol [17]. Various oligoesters (glycolysis products) can be obtained by PET depolymerization using DPG.…”

Oligoester and Polyester Production via Acido-alcoholysis of PET Waste

“…[7][8][9] In some cases, the glycolysis products were further used without any purification steps [41][42][43]. Our own experience (unpublished results) and other studies on glycolysis show molecular mass distribution usually with well distinguishable peaks.…”

“…The usual conditions for these reactions are assumingly 180-220°C, at atmospheric pressure in inert gas atmosphere in the presence of a catalyst. [4][5][6][7][8][9] The reaction conditions may vary, higher temperatures and pressurized reactors, even supercritical conditions have been used in previous studies. [22][23] Methanolysis and glycolysis serve as a way to recover and reuse ethylene glycol, terephthalic acid or dimethyl terephthalate or bis(hydroxyethyl)terephthalate (BHET) for PET production.…”

“…There are several well known solvolytic methods such as alcoholysis (glycolysis and methanolysis), aminolysis, ammonolysis and hydrolysis. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] The main purpose of these methods is to obtain different chemicals, mostly monomers for the reproduction of polyesters. The methanolysis, glycolysis and hydrolysis of PET results in terephthalic acid or its esters and ethylene glycol that can be used to repoduce PET with properties equal to the virgin material.…”