CNTs杂化粒子改性PP/PGA复合材料的结构与性能

Structure and properties of PP/PGA composites modified by CNTs hybrids

为解决聚丙烯/聚乙醇酸(PP/PGA)共混物由于相容性较差导致力学性能存在局限性的问题,采用过硫酸铵-胺氧化还原引发体系,通过表面引发接枝聚合法(SIP)制备了碳纳米管接枝聚甲基丙烯酸缩水甘油酯杂化粒子(CNTs@PGMA),以CNTs@PGMA杂化粒子和聚丙烯接枝马来酸酐(PP-g-MAH)为协同增容体系,通过熔融共混法制备了PP/PGA/CNTs复合材料,采用傅里叶变换红外光谱仪和透射电子显微镜对CNTs@PGMA进行了表征,结果表明PGMA通过SIP成功接枝在CNTs表面。采用拉伸测试、差示扫描量热仪、热重分析、旋转流变和降解试验等方法研究了CNTs@PGMA用量对复合材料力学性能、热性能、降解性能和流变行为的影响。结果表明,在PP/PGA/PP-g-MAH体系中加入CNTs@PGMA后其相容性得到提升,随杂化粒子用量增加,复合材料拉伸强度先增大后减小,热稳定性得到提升,PGA结晶逐渐受限甚至无熔融峰出现。杂化粒子的加入形成了三维网络结构,提高了复合材料熔体弹性,熔体表现出更强的非牛顿性和剪切变稀行为,同时PGA的降解过程受到抑制。当CNTs@PGMA用量为5份时,复合材料的拉伸强度最大为41.25 MPa,断裂伸长率为66.03%,PGA在42 d时的降解率下降至10%以内,拉伸强度维持率达到91%。

In order to solve the problem of limited mechanical properties of polypropylene/polyglycolic acid(PP/PGA)blends due to poor compatibility,carbon nanotubes grafted polyglycidyl methacrylate hybrid particles(CNTs@PGMA)were prepared by surface-initiated graft polymerization(SIP)based on ammonium persulfate-amine redox initiation system.PP/PGA/CNTs were prepared by melt blending using CNTs@PGMA with polypropylene grafted maleic anhydride(PP-g-MAH)as the synergistic compatibilization system.The prepared CNTs@PGMA were characterized by infrared spectroscopy and transmission electron microscopy,the results show that PGMA is successfully grafted on the surface of CNTs by SIP method.The effects of CNTs@PGMA content on the mechanical,thermal,degradation properties,and rheological behavior of the composites were investigated by tensile test,differential scanning calorimetry,thermogravimetry,rotational rheology test and degradation experiment.The results show that the compatibility of the PP/PGA/PP-g-MAH system is improved by adding CNTs@PGMA.With the increase of hybrid particle content,the tensile strength of the composites first increase and then decrease,the thermal stability is improved,and the crystallization of PGA is gradually limited to no melting peak.A three-dimensional network structure is formed with the introduction of hybrid particles,which improves the elasticity,non-Newtonian,and shear thinning behavior of composite melt.Meanwhile,the degradation process of PGA is also inhibited.When the content of CNTs@PGMA is 5 phr,the maximum tensile strength of the composites is 41.25 MPa,the elongation at break is 66.03%,the degradation rate of PGA at 42 days is reduced to less than 10%,and the tensile strength maintenance rate is reached 91%.