Chain extension of recycled poly(ethylene terephthalate) with 2,2′‐Bis(2‐oxazoline)

Abstract

SYNOPSIS2,2'-Bis (2-oxazoline) was used as a chain extender during processing in a twin-screw extruder with the aim of counteracting degradation phenomena in recycled poly (ethylene terephthalate) (PET). The same experiments were performed on fiber-grade PET for comparison purposes. Rheological characterization showed that while the melt viscosity of fiber-grade PET at constant temperature and shear rate is quite constant with time, that of recycled P E T decreases dramatically. By addition of oxazoline, an increase of melt viscosity occurs for fiber-grade PET, whereas for recycled PET, thermal and hydrolitic degradation effects are partially compensated. Characterization was performed by solution viscosity measurements, gel permeation chromatography, and COOH end-group titration on samples obtained a t variable residence times at 280°C. Lower molecular weights accompanied by a higher amount of COOH were observed; the use of oxazoline resulted in higher molecular weights and lower COOH concentrations at equal residence times, while polydispersity did not vary. 0 1993 John Wiley & Sons, Inc.

Toughening of recycled poly(ethylene terephthalate) with a maleic anhydride grafted SEBS triblock copolymer

“…These compounds reacted with the carboxyl or hydroxyl end groups of PET and resulted in chain-extended PET with very low carboxyl content. Cardi et al 27 confirmed the chain extension effect of 2,2Ј-bis(2-oxazoline) on recycled PET. Haralabakopoulos et al 28 showed that some commercially available cyclic diepoxides were effective in chain extension of PET.…”

Reactive extrusion of recycled poly(ethylene terephthalate) with polycarbonate by addition of chain extender

“…These compounds reacted with the carboxyl or hydroxyl end group of PET and resulted in chain-extended PET with low carboxyl content. Cardi et al 27 confirmed the chain extension of recycled PET by adding 2,2-bis(2-oxazoline). Haralabakopoulos et al 28 showed that some commercially available cyclic diepoxides were effective in chain extension of PET.…”

Plastic Degradation and Its Environmental Implications with Special Reference to Poly(ethylene terephthalate)

“…The first class of contaminants is acids and acid-producing contaminants, for example, PVC, which produces hydrochloric acid [38,58]. Acids act as catalysts for chain cleavage reactions [59,60]. Similarly, elevated water content can lead to chain breakage through hydrolysis.…”