Synthesis and characterization of novel polyurethanes based on aminolysis of poly(ethylene terephthalate) wastes, and evaluation of their thermal and mechanical properties

Abstract

BACKGROUND: Much research is currently directed towards recycling post‐consumer poly(ethylene terephthalate) (PET) products for both environmental and economic reasons. Aminolysis of PET wastes using different amines, such as allylamine, morpholine, hydrazine and polyamines, leads to different reaction products as diamides of terephthalic acid, which do not possess any potential for further chemical reactions. In the past, the use of ethanolamine has been investigated for the aminolytic degradation of PET waste in the presence of different simple chemicals such as sodium acetate as catalysts. The product obtained, bis(2‐hydroxyethylene) terephthalamide (BHETA), has potential for further reactions to obtain useful products. Nevertheless, there has been no report on using recycled BHETA from PET to synthesize polyurethanes. RESULTS: In this research the product of aminolysis of PET waste, BHETA, was prepared. Then novel polyurethanes were synthesized based on the BHETA prepared, 1,4‐butanediol, ether‐type polyol and various molar ratios of hexamethylene diisocyanate. To evaluate the effect of BHETA, the properties of the polyurethanes without and with BHETA were compared. Fourier transform infrared spectra, thermal transitions, degradation, swelling ratio and chemical resistance of the synthesized polyurethanes were investigated. Also, the polyurethanes were applied as adhesives on various substrates. Comparison of the maximum bond strength of the synthesized polyurethane to that of commercial adhesives shows an about 2.2‐fold increase. CONCLUSION: It is possible to synthesize new polyurethanes with interesting properties using BHETA as an aminolysis product of PET waste. These kinds of materials have potential for many applications, such as adhesives and coatings. Copyright © 2008 Society of Chemical Industry

Oligoester and Polyester Production via Acido-alcoholysis of PET Waste

“…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.…”

Degraded Pet for the Removal of Metal Ions From Aqueous Solution

“…Chemical degradation of PET produces low molecular weight compounds with functional groups taken from the nucleophilic agent used in the chemical process, for example, hydroxyl group in glycolysis or amine group in aminolysis 14 . These degradation products have been used as precursors of new products such as fatty amide derivate in textile processes 15 , unsaturated polyester resins 16 , epoxy resin hardeners 17 , and polyurethanes 18 . Due to the nature of the generated functional groups, products of PET chemical recycling can be considered as an alternative for the removal of metal ions from water and consequently help resolve many problems caused by plasticaccumulation 19,20 .…”

From PET Waste to Novel Polyurethanes

“…Large numbers of Post-consumer PET products especially bottles and containers do not create a direct hazard to the environment, but as a problem due to its substantial volume fraction in the solid waste streams, its high resistance to the atmosphere, its poor biodegradability and photo degradability. PET accounts for more than 8% by weight and 12% by volume of the world's solid waste (Shamsi R et al, 2009). …”

“…There are few reports on the usage of recycled BHETA from PET to synthesis of polyurethanes. Depolymerization of the PET waste, using ethanolamine to obtain BHETA and BHETA-based polyurethanes, has been investigated in our works (Shamsi R et al, 2009;Mohammadi M et al, 2010;Mir Mohamad Sadeghi G et al, 2011). This chapter aims at the study on synthesis of novel polyurethanes based on PET waste.…”