Study of the morphology of semicrystalline poly(ethylene terephthalate) by hydrolysis etching

Abstract

Semicrystalline poly(ethylene terephthalate) was hydrolysed in water at 180°C under elevated pressure and subsequently treated with ethanol, following the etching process first developed by Miyagi and Wunderlich. The weight loss, the wide-angle X-ray scattering and the molecular weight were measured as a function of etching time. It was found that even at the end of the etching process not all the amorphous material could be removed by the hydrolysis treatment. By comparing the obtained results with those derived from an elaborate small-angle X-ray scattering study and with wide-angle X-ray scattering measurements, it was concluded that only those amorphous regions lying outside of the lamellar stacks were removed. Subsequently, the lamellar stacks themselves were attacked. It was also found that at the very beginning of the hydrolysis process additional crystals were formed in the material.

Degradation and Recyclability of Poly (Ethylene Terephthalate)

“…The degradation processes that occur are influenced by the moisture and oxygen present in the system. Polyethylene terephthalate is shown to give dual slopes of initial fast rate and later slow rate of degradation [37]. The initial rate is attributed to hydrolysis of residual water and the latter slow rate is attributed the thermal degradation initiated by thermal energy.…”

“…Recycling of polyester has become an important process from the environmental point of view and it has given commercial opportunity due to wide spread use and availability of PET bottles, packages and fibers [37][38][39]. While mechanical recycling is well established, chemical recycling is highly dependent of the manner in which the depolymerization is carried out.…”

Tearing and reliability of photovoltaic module backsheets

“…We hypothesize that during the damp heat treatment of the PET, water molecules diffused into the amorphous region in the PET and hydrolyzed the polymer chains. It has been shown that small crystalline phases can form between the primary crystalline domains in PET (Figure C), and these small crystalline phases contribute to the emergence of the new peaks in the WAXS data at DH2000. Hydrolysis in the PET also led to a lower molecular weight, causing the embrittlement of the PET as demonstrated by the tearing and tensile characterization (Figures and ).…”

“…Additionally, during the second heating cycle, PET after DH2000 exhibited melting peaks that were larger and at higher temperatures than PET after DH0. Such difference is likely due to the hydrolysis of the PET during the damp heat treatment, which produces shorter polymer chains that can crystallize more easily, leading to higher crystallinity and formation of more stable crystals …”

Kinetic Studies on Saponification of Poly(ethylene terephthalate) Waste Powder Using Conductivity Measurements

“…Hydrolysis of PET gives terephthalic acid (TPA) and ethylene glycol (EG) as a reaction product [10][11][12][13]. Aminolysis and methanolysis [14][15][16] give dimethyl terephthalate (DMT) and terephthalamide as a reaction product. Acid alkali and water hydrolysis of PET waste in organic solvent have been reported by several workers [17][18][19][20][21].…”