Toughening effects of poly(butylene terephthalate) with blocked isocyanate‐functionalized poly(ethylene octene)

BACKGROUND: Blocked isocyanate‐functionalized polyolefins have great potential for use in semicrystalline polymer blends to obtain toughened polymers. In this study, poly(butylene terephthalate) (PBT) was blended with allyl N‐[2‐methyl‐4‐(2‐oxohexahydroazepine‐1‐carboxamido)phenyl] carbamate‐functionalized poly(ethylene octene) (POE‐g‐AMPC). RESULTS: New peaks at 2272 and 1720 cm−1, corresponding to the stretching vibrations of NCO and the carbonyl of NHCON, respectively, in AMPC, appeared in the infrared spectrum of POE‐g‐AMPC. Both rheological and X‐ray photoelectron spectroscopy results indicated a new copolymer was formed in the reactive blends. Compared to uncompatibilized PBT/POE blends, smaller dispersed particle sizes with narrower distribution were found in the compatibilized PBT/POE‐g‐AMPC blends. There was a marked increase in impact strength by about 10‐fold over that of PBT/POE blends with the same rubber content and almost 30‐fold higher than that of pure PBT when the POE‐g‐AMPC content was 25 wt%. CONCLUSION: The blocked isocyanate‐functionalized POE is an effective toughener for semicrystalline polymers. Super‐toughened PBT blends can be obtained when the POE‐g‐AMPC content is equal to or more than 15 wt%.