The preparation of modified polyamide clay nanocomposite/recycled maleic anhydride polyamide 6 and blending with low density polyethylene for film blowing application

Abstract

Generally, polyamide cannot be used as film blowing material because of its unsuitable properties. In this study, polyamide 6 clay nanocomposite (cPA) and styrene maleic anhydride copolymer (SMA) were mixed in various ratios for the preparation of modified polyamide 6 clay nanocomposite SxcPAy resins by reactive extrusion. The S1cPA14 resin was blended with recycled maleic anhydride polyamide (rPA) to form the (S1cPA14)x rPAy resins. Finally, they were mixed with LDPE in 1:9 ratio to afford (SxcPAy)1LDPE9 and ((S1cPA14)x rPAy)1LDPE9 resins, respectively, followed by film blowing and the analyses of the physicochemical properties of resins. The FTIR spectrum illustrated that the C=O symmetric and asymmetric absorption fingerprint peaks in the anhydride (-OC-O-CO-) group of SMA disappeared and the new characteristic absorption peak of-CO-N-CO- of imides was observed. The anhydride functional group of SMA underwent reactive extrusion with the terminal amino group of cPA to generate the imides structure. The thermal properties showed that the glass transition temperature and crystallinity of SxcPAy and (S1cPA14)x rPAy resins increased with increasing SMA and S1cPA14 contents. The Tg (85.4.0°C) of (S1cPA14)12 rPA1 resin were enhanced significantly, with 30°C higher than cPA. In terms of tensile mechanical properties, S1cPA14 test pieces demonstrated the highest Young’s modulus and tensile strength. After mixing with LDPE, the tensile mechanical properties of (SxcPAy)1LDPE9 and ((S1cPA14)x rPAy)1LDPE9 resins and films were both higher than that of LDPE. ((S1cPA14)12 rPA1)1LDPE9 film shown the best tensile properties and barrier performance compared with other films due to the optimal rPA content could assisted SMA as a better compatibilizer to improve the dispersion and compatibility of cPA in HDPE. It was worth noting that (SxcPAy)1LDPE9 and ((S1cPA14)x rPAy)1LDPE9 resins were formed by film blowing at the processing temperature of 140°C followed by successful preparation of the film.