Fast in situ copolymerization of PET/PEN blends by ultrasonically-aided extrusion
✍ Scribed by Kaan Gunes; Avraam I. Isayev; Xiaopeng Li; Chrys Wesdemiotis
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 522 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0032-3861
No coin nor oath required. For personal study only.
✦ Synopsis
An ultrasonically-aided extrusion process was developed for fast in situ compatibilization of immiscible polymer blends. PET, PEN, and their 50/50 blend were ultrasonically extruded at various amplitudes. PET underwent homopolymerization and degradation, respectively, at ultrasonic amplitudes of 7.5 and 10 mm, while PEN underwent degradation at amplitudes of 5, 7.5, and 10 mm. MALDI-TOF mass spectrometry revealed greater amounts of hydroxyl and carboxyl terminated oligomers in ultrasonically treated PET and PEN, indicating their greater reactivity. Ultrasonic treatment at short residence time led to the enhancement of transesterification reaction in the PEN/PET blend, as shown by 1 H NMR and MALDI-TOF, indicating greater randomization with ultrasonic treatment. The latter was also observed through a shift in T g that closely follows Gibbs-DiMarzio relation and an increase in viscosity of blend with treatment at an amplitude of 10 mm. No crystallinity was observed in the blend due to the already high level of transesterification introduced by extrusion without treatment. Accordingly, crystallinity, mechanical properties, oxygen permeability, and optical clarity of the blend were not influenced by ultrasonic treatment.