Polyamide is an engineering plastic, which has been widely used in industry and life. Polyamide 56, as a green and environmentally friendly bio-based product, is gradually replacing traditional petroleum-based products. However, in terms of auto parts, communication equipment, and mechanical products, a single polyamide monomer is difficult to meet the end-use standard. EPDM-g-MAH (ethylene propylene diene monomer grafted with maleic anhydride) is melt blended with bio-based polyamide 56 (PA56) in a twin-screw extruder to obtain polyamide elastomers with different formulations. Subsequently, its morphology and structure, thermodynamic properties, crystallinity, and mechanical properties were analyzed. The test results show that the composites containing 10% EPDM-g-MAH have better impact resistance and thermal properties in the range of adding 0‑20 wt% EPDM-g-MAH. In the fracture morphology analysis, it is found that the interface between the rubber phase and the polyamide phase fused well, and the elastomer showed the ductile fracture.
In this study, a series of maleic anhydride-grafted ethylene–propylene–diene rubbers (EPDM-g-MAHs) with different grafting degrees were prepared via the rotary evaporation-assisted melt grafting, which could achieve higher grafting rate and smaller gel content than the traditional melt grafting under the same conditions. Morphological observation, thermal analysis, and rheological measurements confirmed that the interfacial compatibility of the core–shell dispersed phases was enhanced by increasing the composition ratio of EPDM-g-MAH/EPDM or the grafting degree of the prepared EPDM-g-MAHs in the polypropylene (PP) blends. A remarkable improvement in toughness and a little loss in strength and modulus were obtained in the PP blends by regulating the dual interfaces of the core–shell dispersed phases. A new insight into the toughening mechanism of core–shell particles was presented in this work. The balance between toughness and strength could be attributed to the strong dual interfacial interaction of the core–shell dispersed phases, thereby effectively transferring stress. In addition to the conventionally internal cavitation in the rubber phase and the shear yielding of the PP matrix triggered by stress-concentrated dispersed phases, expanded stress field, elongated core phases, and increased cavitation that occurred at dual interfaces by debonding were regarded to contribute to the toughening effect.
In this paper, we reported a technique for the surface modification of poly-( p -phenylene terephthamide) (PPTA) powder coated with polydopamine (PDOPA). We used air oxidation to self-polymerize dopamine (DOPA) to ensure that the PPTA powder was coated. Our results indicate that the modified surface of PPTA powder enhances compatibility with the polymer matrix without damaging its structure. Additionally, it is possible to control the coating thickness of PDOPA by regulating the reaction time. The modified PPTA powder improved the comprehensive property of ethylene-propylene-diene-terpolymer grafted maleic anhydride (EPDM- g -MAH), and it proved that this method can enhance the strength and electric insulativity of EPDM- g -MAH.
危险品化学品经营许可证（带存储）