Enzymatic and chemical hydrolysis of poly(ethylene terephthalate) fabrics

Abstract

Alkaline and enzymatic hydrolyzes of poly(ethylene terephthalate) fabrics (PET) were mechanistically compared based on released degradation products (HPLC‐UV‐RI) and changes in surface properties [hydrophilicity, cationic dyeing, X‐ray photoelectron spectroscopy (XPS)]. Enzymatic hydrolysis led to an increase in the amount of hydroxyl and carboxyl groups on the surface resulting in an enhanced water absorption and dyeability. Enzymes partially adsorbed to PET fabrics during hydrolysis were completely removed by subsequent extraction according to XPS analysis. In contrast to the enzyme treatment, alkaline hydrolysis did not lead to an increase of hydroxyl and acid groups according to XPS while both treatments caused a substantial increase in hydrophilicity and were more effective on amorphous fibers. Alkaline hydrolysis led to a greater increase in the K/S value after cationic dyeing due to enlarged surface area. Consequently, ESEM‐images demonstrated that alkaline treatment drastically affected the surface morphology of the polymer resulting in crater‐like structures of the fibers, whereas after enzymatic treatment the morphology of the fibers remained unchanged. To reach similar benefits in hydrophilicity, drastically higher amounts of degradation products were released during alkaline hydrolysis as also indicated by >6% weight loss compared to <1% after enzyme treatment. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6435–6443, 2008

A New Esterase from Thermobifida halotolerans Hydrolyses Polyethylene Terephthalate (PET) and Polylactic Acid (PLA)

“…The amount of MHET and TA released were comparable with around 19.8 and 21.5 mmol/mol of enzyme, respectively. Previously, for a lipase from T. lanuginosus [29] a ten times higher release of MHET than TA from amorphous fibers and 3 times more from semi-crystalline PET fibers was reported. Interestingly, only in the case of amorphous fibers was BHET detected.…”

“…Among cutinases, representatives from Aspergilllus oryzae, Humicola insolens [35], Penicillium citrinum [36], Fusarium solani [30,37], Thermobifida fusca [29] and Thermobifida cellulolysitica [27] have been described to hydrolyze PET. Considerably fewer lipases have been described to hydrolyze PET, including enzymes from Candida antarctica [25], Thermomyces lanuginosus [32], Burkholderia spp.…”

“…Cutinases [30][31][32], lipases [29,32], esterases [26,30,33] including paranitrobenzyl esterase [34] have been assessed for this purpose.…”

“…Poly(alkyleneterephthalates) (PAT), and particularly polyethylene terephthalate (PET), are one of the most widely used synthetic polymers worldwide [24] which can be functionalized via limited enzymatic hydrolysis of the ester bond of the polymer backbone [25][26][27][28][29]. Cutinases [30][31][32], lipases [29,32], esterases [26,30,33] including paranitrobenzyl esterase [34] have been assessed for this purpose.…”

Role of Biotechnology in the Treatment of Polyester Fabric

“…Bruekner et al [46] compared the alkaline and enzymatic hydrolysis of PET fabrics based on released degradation products assayed by HPLC and changes in surface properties affecting hydrophilicity, cationic dyeing and X-ray photoelectron spectroscopy (XPS).…”