The Effect of Compatibilization on the Properties and Foaming Behavior of Poly(ethylene terephthalate)/Poly(ethylene-octene) Blends

The methodology for improving the properties and foaming behavior of poly (ethylene terephthalate) (PET)/poly(ethylene-octene) (POE) blends through compatibilization was proposed. In this paper, PET/POE blends were prepared through a melt blending method, POE was employed as elastomer toughener, maleic anhydride grafted POE (mPOE) was selected as compatibilizer, and pyromellitic dianhydride (PMDA) was used as chain extender. The content of mPOE was changeable to study the effect of compatibility on crystallization behavior, toughness, dispersion morphology, and rheological behavior of PET/ POE blends. The results demonstrated that the crystallization peak of PET/POE blends shifted towards high temperatures from 196.97°C to 201.24°C with the content of mPOE increasing. The brittle-ductile transition for PET/POE blends occurred at the mPOE content in the range of 4–5 phr. The particle size of POE dispersed phase decline firstly and then was almost unchanged with an increasing content of mPOE. The storage modulus and complex viscosity of compatibilized PET/POE blends were obviously higher than that of uncompatibilized PET/POE blends. Then PET/POE blends were foamed using supercritical CO2 as physical blowing agent. The results showed that the cell size, cell density, and tensile properties of the PET/POE blending foams were affected by the content of mPOE strongly. With the content of mPOE, the cell size decreased and then kept stable as well as the cell density the trend of cell size increased then remained unchanged. In addition, the elongation at break of PET/POE blending foams was higher than that of the uncompatibilized PET/POE blending foam. PET/POE blending foams with fine cell morphology and good ductility could be achieved with a proper content of compatibilizer in the blends.