iPP/PET原位微纤复合材料的超临界二氧化碳发泡行为
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摘要
利用微纳层叠共挤技术中独特的剪切拉伸复合流动场作用实现聚对苯二甲酸乙二醇酯(PET)在聚丙烯(i PP)中的原位微纤化,研究了PET的原位微纤化对i PP/PET复合材料发泡行为的影响。扫描电子显微镜结果显示,经过微纳层叠共挤装置挤出后,PET在i PP中形成直径为0.2~1μm的微纤。PET微纤化显著地改善了i PP的结晶性能、流变性能及发泡性能。差示扫描量热测试结果表明,PET微纤对i PP具有明显的异相成核作用,能提高i PP的结晶温度和熔点;拉伸流变行为分析发现,PET微纤的形成使得i PP产生明显的应变硬化现象;通过超临界二氧化碳发泡发现,i PP/PET原位微纤复合材料的泡孔比纯i PP更加稳定,尺寸更小,密度更大,且泡孔内存在三维微纤网络结构。
The isotactic polypropylene( i PP)/polyethylene terephthalate( PET) in situ microfibrillar composites were prepared by micro-nano-stack co-extrusion technique based on its strong shear-elongational mixed flow field,and its effect on the foaming behavior of i PP was studied. The scanning electron micrographs illustrate that the micro-nano-stack co-extrusion process elongates the dispersed PET phase in the i PP matrix into high-aspect-ratio microfibrils with the diameter of 0. 2 ~ 1 μm. The formation of PET microfibrils greatly affect the crystalline behaviors,rheological and foaming properties of i PP. The differential scanning calorimetry results reveal that the heterogeneous nucleation sites provided by the PET microfibrils enhance the crystallization and melting temperature of i PP. Uniaxial extensional viscosity test shows a strain-hardening behavior in the i PP/PET microfibrillar composites,which cannot be observed in the neat i PP. Supercritical CO_2 was used to investigate the effect of the PET microfibrils on the foaming behavior of i PP. Results reveal that the presence of PET microfibrils in i PP yields foams that exhibit smaller cell size,larger cell density and entangled microfibrils networks exist in cell.
The isotactic polypropylene( i PP)/polyethylene terephthalate( PET) in situ microfibrillar composites were prepared by micro-nano-stack co-extrusion technique based on its strong shear-elongational mixed flow field,and its effect on the foaming behavior of i PP was studied. The scanning electron micrographs illustrate that the micro-nano-stack co-extrusion process elongates the dispersed PET phase in the i PP matrix into high-aspect-ratio microfibrils with the diameter of 0. 2 ~ 1 μm. The formation of PET microfibrils greatly affect the crystalline behaviors,rheological and foaming properties of i PP. The differential scanning calorimetry results reveal that the heterogeneous nucleation sites provided by the PET microfibrils enhance the crystallization and melting temperature of i PP. Uniaxial extensional viscosity test shows a strain-hardening behavior in the i PP/PET microfibrillar composites,which cannot be observed in the neat i PP. Supercritical CO_2 was used to investigate the effect of the PET microfibrils on the foaming behavior of i PP. Results reveal that the presence of PET microfibrils in i PP yields foams that exhibit smaller cell size,larger cell density and entangled microfibrils networks exist in cell.
引文
[1]杨勇,郑文革,张好斌,等.CO2微孔发泡聚碳酸酯/聚苯乙烯[J].塑料,2010,39(1):35-37.Yang Y,Zheng W G,Zhang H B,et al.Microcellular foaming of polycarbonate/polystyrene blends with CO2[J].Plastics,2010,39(1):35-37.
[2]李文翔,张洋,张思思,等.发泡聚丙烯改性与制备研究进展[J].胶体与聚合物,2017,35(1):45-48.Li W X,Zhang Y,Zhang S S,et al.Research progress of polypropylene foam[J].Chinese Journal of Colloid&Polymer,2017,35(1):45-48.
[3]Cao K,Li Y,Lu Z Q,et al.Preparation and characterization of high melt strength polypropylene with long chain branched structure by the reactive extrusion process[J].J.Appl.Polym.Sci.,2011,121:3384-3392.
[4]Su F H,Huang H X.Supercritical carbon dioxide-assisted reactive extrusion for preparation long-chain branching polypropylene and its rheology[J].J.Supercrit.Fluids,2011,56:114-120.
[5]An Y,Zhang Z,Wang Y,et al.Structure and properties of high melt strength polypropylene prepared by combined method of blending and crosslinking[J].J.Appl.Polym.Sci.,2010,116:1739-1746.
[6]Lee L J,Zeng C,Cao X,et al.Polymer nanocomposite foams[J].Compos.Sci.Technol.,2005,65:2344-2363.
[7]Okamoto M,Nam P H,Maiti P,et al.Biaxial flow-induced alignment of silicate layers in polypropylene/clay nanocoposite foam[J].Nano Lett.,2001,1:503-505.
[8]Hong J S,Ahn K H,Lee S J.Strain hardening behavior of polymer blends with fibril morphology[J].Rheol.Acta,2005,45:202-208.
[9]Yokohara T,Nobukawa S,Yamaguchi M.Rheological properties of the mechanics of entangled materials[J].J.Rheol.,2011,55:1205-1218.
[10]Kakroodi A R,Kazemi Y,Ding W D,et al.Poly(lactic acid)-based in situ microfibrillar composite with enhanced crystallization kinetics,mechanical properties,rheological behavior,and foaming ability[J].Biomacromolecules,2015,16:3925-3935.
[11]Fakirov S,Evstatiev M.Microfibrillar reinforced composites-new materials from polymer blends[J].Adv.Mater.,1994,6:395-398.
[12]Ali R,Chul B P.Dispersed polypropylene fibrils improve the foaming ability of a polyethylene matrix[J].Polymer,2014,55:4199-4205.
[13]Jayanarayanan K,Thomas S,Joseph K.Morphology,static and dynamic mechanical properties of in situ microfibrillar composites based on polypropylene/poly(ethylene terephthalate)blends[J].Composites Part A,2008,39:164-175.
[14]Taepaiboon P,Junkasem J,Dangtungee R,et al.In situ microfibrillar-reinforced composites of isotactic polypropylene/recycled poly(ethylene terephthalate)system and effect of compatibilizer[J].J.Appl.Polym.Sci.,2006,102:1173-1181.
[15]Li Z M,Yang M B,Xie B H,et al.In-situ microfiber reinforced composite based on PET and PE via slit die extrusion and hot stretching:influence of hot stretching ratio on morphology and tensile properties at a fixed composition[J].Polym.Eng.Sci.,2003,43:615-628.
[16]Wei L Q,Qi Y H,Sun J,et al.Improving the foaming and mechanical properties of the in situ microfiber-reinforced polyethylene terephthalate/polypropylene composites through compatibilization[J].Polym.Bull.,2017,74:4055-4068.
[17]Wang K,Wu F,Zhai W T,et al.Effect of polytetrafluoroethylene on the foaming behaviors of linear polypropylene in continuous extrusion[J].J.Appl.Polym.Sci.,2013,129:2253-2260.
[18]Ji C Q,Xie M C,Chang B B,et al.β-crystal in injection moulded poly(ethylene terephthalate)fibre/isotactic polypropylene composite[J].Composites Part A,2013,46:26-33.
[19]Zhao Z G,Yang Q,Xiang Z,et al.Effect of in situ poly(ethylene terephthalate)(PET)microfibrils on the morphological structure and crystallization behavior of isotactic polypropylene(i PP)under an intensive shear rate[J].Polym.Adv.Technol.,2015,26:1275-1284.
[20]王卫霞,周帅,辛忠,等.基于苯乙烯/丙烯酸酯基硅油的高熔体强度聚丙烯的流变性能和发泡性能[J].石油化工,2015,44(10):1239-1245.Wang W X,Zhou S,Xin Z,et al.Rheology and foaming properties of high melt strength polypropylene based on styrene/acrylic silicone oil[J].Petrochemical Technology,2015,44(10):1239-1245.
[21]Zhou S,Zhao S,Xin Z.Preparation and foamability of high melt strength polypropylene based on grafting vinyl polydimethylsiloxane and styrene[J].Polym.Eng.Sci.,2015,55:251-259.
[2]李文翔,张洋,张思思,等.发泡聚丙烯改性与制备研究进展[J].胶体与聚合物,2017,35(1):45-48.Li W X,Zhang Y,Zhang S S,et al.Research progress of polypropylene foam[J].Chinese Journal of Colloid&Polymer,2017,35(1):45-48.
[3]Cao K,Li Y,Lu Z Q,et al.Preparation and characterization of high melt strength polypropylene with long chain branched structure by the reactive extrusion process[J].J.Appl.Polym.Sci.,2011,121:3384-3392.
[4]Su F H,Huang H X.Supercritical carbon dioxide-assisted reactive extrusion for preparation long-chain branching polypropylene and its rheology[J].J.Supercrit.Fluids,2011,56:114-120.
[5]An Y,Zhang Z,Wang Y,et al.Structure and properties of high melt strength polypropylene prepared by combined method of blending and crosslinking[J].J.Appl.Polym.Sci.,2010,116:1739-1746.
[6]Lee L J,Zeng C,Cao X,et al.Polymer nanocomposite foams[J].Compos.Sci.Technol.,2005,65:2344-2363.
[7]Okamoto M,Nam P H,Maiti P,et al.Biaxial flow-induced alignment of silicate layers in polypropylene/clay nanocoposite foam[J].Nano Lett.,2001,1:503-505.
[8]Hong J S,Ahn K H,Lee S J.Strain hardening behavior of polymer blends with fibril morphology[J].Rheol.Acta,2005,45:202-208.
[9]Yokohara T,Nobukawa S,Yamaguchi M.Rheological properties of the mechanics of entangled materials[J].J.Rheol.,2011,55:1205-1218.
[10]Kakroodi A R,Kazemi Y,Ding W D,et al.Poly(lactic acid)-based in situ microfibrillar composite with enhanced crystallization kinetics,mechanical properties,rheological behavior,and foaming ability[J].Biomacromolecules,2015,16:3925-3935.
[11]Fakirov S,Evstatiev M.Microfibrillar reinforced composites-new materials from polymer blends[J].Adv.Mater.,1994,6:395-398.
[12]Ali R,Chul B P.Dispersed polypropylene fibrils improve the foaming ability of a polyethylene matrix[J].Polymer,2014,55:4199-4205.
[13]Jayanarayanan K,Thomas S,Joseph K.Morphology,static and dynamic mechanical properties of in situ microfibrillar composites based on polypropylene/poly(ethylene terephthalate)blends[J].Composites Part A,2008,39:164-175.
[14]Taepaiboon P,Junkasem J,Dangtungee R,et al.In situ microfibrillar-reinforced composites of isotactic polypropylene/recycled poly(ethylene terephthalate)system and effect of compatibilizer[J].J.Appl.Polym.Sci.,2006,102:1173-1181.
[15]Li Z M,Yang M B,Xie B H,et al.In-situ microfiber reinforced composite based on PET and PE via slit die extrusion and hot stretching:influence of hot stretching ratio on morphology and tensile properties at a fixed composition[J].Polym.Eng.Sci.,2003,43:615-628.
[16]Wei L Q,Qi Y H,Sun J,et al.Improving the foaming and mechanical properties of the in situ microfiber-reinforced polyethylene terephthalate/polypropylene composites through compatibilization[J].Polym.Bull.,2017,74:4055-4068.
[17]Wang K,Wu F,Zhai W T,et al.Effect of polytetrafluoroethylene on the foaming behaviors of linear polypropylene in continuous extrusion[J].J.Appl.Polym.Sci.,2013,129:2253-2260.
[18]Ji C Q,Xie M C,Chang B B,et al.β-crystal in injection moulded poly(ethylene terephthalate)fibre/isotactic polypropylene composite[J].Composites Part A,2013,46:26-33.
[19]Zhao Z G,Yang Q,Xiang Z,et al.Effect of in situ poly(ethylene terephthalate)(PET)microfibrils on the morphological structure and crystallization behavior of isotactic polypropylene(i PP)under an intensive shear rate[J].Polym.Adv.Technol.,2015,26:1275-1284.
[20]王卫霞,周帅,辛忠,等.基于苯乙烯/丙烯酸酯基硅油的高熔体强度聚丙烯的流变性能和发泡性能[J].石油化工,2015,44(10):1239-1245.Wang W X,Zhou S,Xin Z,et al.Rheology and foaming properties of high melt strength polypropylene based on styrene/acrylic silicone oil[J].Petrochemical Technology,2015,44(10):1239-1245.
[21]Zhou S,Zhao S,Xin Z.Preparation and foamability of high melt strength polypropylene based on grafting vinyl polydimethylsiloxane and styrene[J].Polym.Eng.Sci.,2015,55:251-259.