Preparation and characterization of organic montmorillonite modified hyperbranched polyamide 6
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摘要: 以枝化剂为超支化聚酰胺6(PA6)的引发剂,配以含有端羧基官能团的有机改性剂改性的有机蒙脱土(O-MMT),经原位开环接枝聚合制备了O-MMT/超支化PA6复合材料。通过FTIR和TEM表征了超支化PA6与O-MMT的接枝情况以及O-MMT在基体中的分散形态。研究了O-MMT对超支化PA6结晶性能、熔体流动性能和力学性能的影响。结果表明:O-MMT呈剥离态和插层态分散于超支化PA6基体中,且与PA6分子链段产生化学键合,形成网络交联结构。网络交联结构使O-MMT/超支化PA6复合材料与超支化PA6相比熔体流动指数急剧下降。另外,O-MMT使超支化PA6的α晶型消失,且使仅有γ晶型的超支化PA6的结晶度降低。但随O-MMT 含量增加,O-MMT/超支化PA6复合材料的强度逐步提高,拉伸强度从38.4 MPa提高至60.8 MPa。复合材料的韧性也得到大幅度提高,断裂伸长率从2.1%提高至70.1%,无缺口冲击强度从20.3 kJ/m2急剧提高至291.8 kJ/m2。Abstract: With branched agent as the initiator of hyperbranched polyamide 6 (PA6), with organic modifier modified organic montmorillonite (O-MMT) which has the terminal carboxyl group, O-MMT/hyperbranched PA6 composites were prepared via in situ ring-opening graft polymerization. The grafting condition of hyperbranched PA6 and O-MMT, dispersing morphology of O-MMT in matrix were characterized by FTIR and TEM, and the effects of O-MMT on crystallization properties, melt flow properties and mechanical properties of hyperbranched PA6 were studied. Results show that O-MMT is exfoliated and intercalated dispersing in hyperbranched PA6 matrix, and chemically bonds with PA6 molecular chains to form crosslinked network structure, which makes the melt flow index of O-MMT/hyperbranched PA6 composites decrease sharply compared with hyperbranched PA6. In addition, O-MMT can make the α-crystal of hyperbranched PA6 disappear, and make crystallization degree of hyperbranched PA6 with only γ-crystal decrease. However, with the increase of O-MMT content, the strength of O-MMT/hyperbranched PA6 composites increase gradually, the tensile strength increase from 38.4 MPa to 60.8 MPa, the toughness of composites also has been greatly improved, the elongation at break increases from 2.1% to 70.1%, the un-notched impact strength increases from 20.3 kJ/m2 increase to 291.8 kJ/m2 sharply.
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Key words:
- polyamide 6 /
- hyperbranched /
- organic montmorillonite /
- in situ grafted /
- composites
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