NR/PP和NR-g-PMMA/PP两种热塑性弹性体的结构与性能
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摘要
采用动态硫化法制备了天然橡胶(NR)/聚丙烯(PP)和NR-甲基丙烯酸甲酯接枝共聚物(NR-g-PMMA)/PP两种共混型热塑性弹性体。采用扫描电镜(SEM)、差示量热扫描法(DSC)、热重分析法(TGA)以及物理机械性能测试对样品进行了表征,对比了两种弹性体的结构与性能。结果表明,两种共混物均呈现热塑性弹性体典型的"海-岛"相结构,NR-g-PMMA分散相的粒径更大且更容易发生团聚现象;当PP质量分数为30%时,NR-g-PMMA/PP的拉伸强度和100%定伸应力明显高于NR/PP。DSC分析表明NR-g-PMMA/PP中PP的结晶度高于NR/PP。TGA的结果表明,两种热塑性弹性体的降解均分为两个阶段,第一个阶段为NR和NR-g-PMMA的降解;第二个阶段为PP的降解,两种弹性体的热稳定性相差不大。
This works investigated the morphology and properties of two kinds of thermoplastic elastomers(TPEs) prepared by the dynamic vulcanization technique.One was the blends of natural rubber(NR) and isotactic polypropylene(PP),and the other was the blends of NR grafted with poly(methyl methacrylate)(NR-g-PMMA) and PP.The morphology of the TPEs examined by scanning electron microscopy disclosed that NR or NR-g-PMMA particles dispersed in PP matrix,and the particle sizes in NR-g-PMMA/PP blends were larger than that in NR/PP at the same content of PP.When the content of PP was 30%,NR-g-PMMA/PP blends had higher tensile strength and tensile stress at 100% than that of NR/PP because of higher crystallinity of PP in NR-g-PMMA/PP blends.The mogravimetry analysis showed that the thermal degradation of the TPEs could be divided into two stages:one was the degradation of NR or NR-g-PMMA and the other was PP.There was little difference in thermal stability between two kinds of TPEs.
This works investigated the morphology and properties of two kinds of thermoplastic elastomers(TPEs) prepared by the dynamic vulcanization technique.One was the blends of natural rubber(NR) and isotactic polypropylene(PP),and the other was the blends of NR grafted with poly(methyl methacrylate)(NR-g-PMMA) and PP.The morphology of the TPEs examined by scanning electron microscopy disclosed that NR or NR-g-PMMA particles dispersed in PP matrix,and the particle sizes in NR-g-PMMA/PP blends were larger than that in NR/PP at the same content of PP.When the content of PP was 30%,NR-g-PMMA/PP blends had higher tensile strength and tensile stress at 100% than that of NR/PP because of higher crystallinity of PP in NR-g-PMMA/PP blends.The mogravimetry analysis showed that the thermal degradation of the TPEs could be divided into two stages:one was the degradation of NR or NR-g-PMMA and the other was PP.There was little difference in thermal stability between two kinds of TPEs.
引文
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[16] SARAMOLEE P,LOPATTANANON N,SAHAKARO K.Preparation and some properties of modified natural rubber bearing grafted poly(methyl methacrylate) and epoxide groups[J].European Polymer Journal,2014,56:1-10.
[2] 胡娅婷,冯莺,陈占勋.动态硫化热塑性弹性体的制备与应用[J].弹性体,2007,17(3):71-75.
[3] 彭政,钟杰平,廖双泉.天然橡胶改性研究进展[J].高分子通报,2014(5):41-48.
[4] 陈尔凡,韩云凤,邓雯雯,等.动态硫化热塑性弹性体的研究进展[J].高分子材料科学与工程,2011,27(3):171-174.
[5] 赵艳芳,廖建和,廖双泉.天然橡胶共混改性的研究概况[J].特种橡胶制品,2006,21(1):55-62.
[6] 刘坚.天然橡胶的化学改性[J].特种橡胶制品,2001,16(3):57-60.
[7] 余和平,王海英,李思东.甲基丙烯酸甲酯与NR的接枝共聚综述[J].橡胶工业,2000,47(2):74-79.
[8] 李俊,刘成果,陈庆民.天然橡胶接枝改性研究进展[J].高分子材料科学与工程,2008,24(3):24-27.
[9] VARGHESE S,ALEX R,KURIAKOSE B.Natural rubber-isotactic polypropylene thermoplastic blends[J].Journal of Applied Polymer Science,2004,92(4):2063-2068.
[10] GEORGE B,MAITI S N,VARMA I K.Graft copolymerization of methyl methacrylate on to natural rubber:Effect of,polymerization conditions on particle morphology[J].Journal of Elastomers and Plastics,2006,38(4):319-331.
[11] THIRAPHATTARAPHUN L,KIATKAMJORNWONG S,PRASASSARAKICH P,et al.Natural rubber-g-methyl methacrylate/poly(methyl methacrylate) blends[J].Journal of Applied Polymer Science,2010,81(2):428-439.
[12] NATTAPON U,METHAKARN J,ZHENG P,et al.Effects of cooling rates on crystallization behavior and melting characteristics of isotactic polypropylene as neat and in the TPVs EPDM/PP and EOC/PP[J].Polymer Testing,2015,44:101-111.
[13] 李超群,姜治伟,王玉荣,等.共混型热塑性弹性体的形变机理[J].高分子材料科学与工程,2008,24(4):10-13.
[14] 张俐娜.高分子物理近代研究方法[M].武汉:武汉大学出版社,2006.
[15] NAKASON C,PECHURAI W,SAHAKARO K,et al.Rheological,thermal,and curing properties of natural rubber-g-poly(methyl methacrylate)[J].Journal of Applied Polymer Science,2010,99(4):1600-1614.
[16] SARAMOLEE P,LOPATTANANON N,SAHAKARO K.Preparation and some properties of modified natural rubber bearing grafted poly(methyl methacrylate) and epoxide groups[J].European Polymer Journal,2014,56:1-10.