Reactive Compatibilization of PBT/EVA Blends with an Ethylene‐Acrylic Acid Copolymer and a Low Molar Mass Bis‐Oxazoline

Abstract

Summary: Polyesters and polyolefins form highly incompatible blends with poor properties and gross morphology that hinder any practical applications. In this work, the possibility to compatibilize an incompatible blend of poly(butylene terephthalate) (PBT) with ethylene vinyl acetate (EVA) by adding a bis‐oxazoline compound, 2,2′‐(1,3‐phenylene)‐bis(2‐oxazoline) (PBO), and an ethylene acrylic acid copolymer (EAA) as compatibilizer precursors has been studied. The results indicate that the binary uncompatibilized blends show poor mechanical properties and a bad morphology with scarce adhesion between the phases. The situation is only slightly improved when the EAA is added while the best performance is achieved when quaternary PBT/EVA/EAA/PBO blends are prepared. In this latter case the elongation at break and the impact strength are doubled and the morphology is deeply improved. The formation of EAA‐g‐(PBO)PBT copolymers in the presence of PBO can be invoked to explain the results and it is demonstrated that the eventual chain extension of PBT or EAA is negligible.

Evolution of the Morphology and Characterization of Compatibilized PBT/EVA Blends Prepared by Reactive Extrusion

“…In this latter case, the viscosity was the highest and the nonNewtonian behavior was the most pronounced of all the investigated blends. As has already been demonstrated in a previous work, [29] this behavior can be interpreted by considering the formation of EAA-g-(PBO)PBT copolymers during the melt processing. These copolymers locate themselves at the interface between the two components, enhancing the adhesion between the two incompatible phases and reducing the particle dimensions.…”

“…Moreover, these morphological results were even better than those obtained in a previous work. [29] To further the analysis of these blends, SEM micrographs at a magnification of 2000Â were recorded (not reported here), and were processed with image analysis software in order to determine the particle dimension distribution curve. The related results are reported in Figure 6.…”

“…[28] In a previous study, [29] some of our group studied the possibility of preparing compatibilized PBT/EVA blends in a laboratory batch mixer, using a bisoxazoline compound (PBO) and an ethylene acrylic acid copolymer (EAA) as promoters of the formation of compatibilizer. The compatibilized blends displayed a finer morphology and better mechanical properties with doubled values of impact strength and elongation at break with respect to the uncompatibilized blends.…”

Evaluation of ethylene–acrylic acid copolymer (EAA)-modified asphalt: Fundamental investigations on mechanical and rheological properties

“…It can serve a compatibilization agent to improve the compatibility between two opposite polar materials. Thus, EAA was widely used as a compatibilizer in plastic processing and so on [33][34][35]. Asphalt is mostly constituted by several kinds of long-chain alkane and has the same polar with polyethylene, so it maybe has good compatibility with EAA.…”

CO and NO desorption from N‐bounded carbonaceous surface complexes: density functional theory calculations

“…In a previous study,29 some of our group studied the possibility of preparing compatibilized PBT/EVA blends in a laboratory batch mixer, using a bisoxazoline compound (PBO) and an ethylene acrylic acid copolymer (EAA) as promoters of the formation of compatibilizer. The compatibilized blends displayed a finer morphology and better mechanical properties with doubled values of impact strength and elongation at break with respect to the uncompatibilized blends.…”