【作者】 段海军；

【导师】 王益龙；

【作者基本信息】 大连理工大学 ， 高分子材料， 2009， 硕士

【摘要】 使用普通单螺杆挤出机研究了三烯丙基异氰酸脲酯、季戊四醇三丙烯酸酯、二糠基硫醚、对苯二酚、二乙烯基苯5种多官能团单体以及苯乙烯-丁二烯-苯乙烯嵌段共聚物、改性乙烯-醋酸乙烯共聚物2种聚合物与聚丙烯(PP)在DCP引发下的熔融挤出反应规律,以寻找能够提高PP熔体强度和抗熔垂性能的反应物。结果表明,二乙烯基苯(DVB)和与对苯二酚(RES)可以显著改善聚丙烯的熔体性能,提高聚丙烯的应用价值。分别研究了RES与DVB对PP的改性效果,探索了引发剂、配方以及最佳工艺条件。研究结果表明,DCP为最佳引发剂,RES添加量为0.2wt%时,改性PP的熔体强度可提高至8KPa.s,提高了4倍;在DVB添加量为0.6wt%时,改性PP的熔体强度可达30 KPa.s,是原料PP的15倍;在改性过程中,添加一定量共单体苯乙烯能够抑制PP的降解和交联,促进长链支化结构的生成。在确定了DVB能够显著改善PP的熔体性能的基础上,又比较了双螺杆挤出机,接枝型反应挤出机,单螺杆挤出机三种挤出机对PP的改善效果。通过对支化产物的熔体性能测试显示,双螺杆挤出机的改性效果较差,接枝型反应挤出机和单螺杆挤出机中的改性效果较好,且最佳的是单螺杆挤出机。对使用单螺杆挤出机制备的DVB改性PP的支化产物做了表征与测试,从熔体性能测试得出,改性PP的熔体流动速率较原料PP降低了4倍左右,熔体强度(30KPa.s)较原料PP(2KPa.s)提高了15倍,改性PP的熔体强度可高于Basell的高熔体强度PP,抗熔垂性能也得到了显著的改善;凝胶含量测试显示,在DVB添加量为0.6wt%时,支化产物的凝胶含量在0.4%左右,不影响PP的加工性能。通过对挤出物直径的测试表明,经改性的支化产物的挤出物直径可达4.3mm,较原料PP(2.2mm)提高了近一倍,说明了改性PP中有长支链结构的存在。流变学性能测试显示,支化产物的表观粘度显著增长,在190℃下,可从原料PP的1340Pa.s增长到8975Pa.s,提高了7倍左右,支化产物的粘流活化能(60740kJ/mol)较原料PP(40470kJ/mol)也得到了显著提高。对使用单螺杆挤出机制备的产物和原料PP做了红外光谱分析对比,结果显示支化产物较原料没有发生变化。通过DSC分析,得出支化产物的熔点略有所提高,而结晶温度提高了9℃左右,结晶度也有明显提高。通过维卡软化点的测试显示,支化产物的耐高温性有所提高。广角X射线(WAXD)分析显示经改性的PP中,有β晶型的生成。力学性能测试显示,改性的产物的拉伸强度和冲击强度都有一定的提高。更多还原

【Abstract】 In order to prepare long chain branching polypropylene and improve the melt strength of polypropylene,the reaction rule of polypropylene with different reactive monomer (TAIC,PETA,FS,RES,DVB) and polymer(modified EVA and SBS) was studied by general single screw extruder in this paper.Experiment results showed that 1,4-benzodiol (RES) and Divinylbenzne(DVB) can improve the melt strength of PP obviously,and enhance the application value of PP.In order to investigate the modification effect of RES and DVB,melt reaction rule of polypropylene with RES and DVB was studied.The results showed that the most suitable initiator was Dicumyl peroxide(DCP),when RES was 0.2wt%,the melt strength of modified PP can increase to 8KPa.s that was 4 times than raw material,when DVB was 0.4wt%,the melt strength of modified PP can increase to 30KPa.s that was 15 times more than that of the raw material.In modified process,co-monomer styrene can restrain degradation and crosslink of PP,and increase the long chain bracning structure in PP.PP melt properties were modified with DVB by various extruders,including single screw extruder,twin-screw extruder and grafting reactive extruder,it was found that the most suitable extruder was single screw extruder.The modified PP prepared by single screw extruder was tested and characterized, Experiment results showed MFR of modified PP decreased obviously,melt strength was 15 times more than that of the raw PP and higher than the Basell Corporation HMS-PP,the melt properties of PP were improved evidently.When DVB was 0.6wt%,the gel of modified PP was 0.4 wt%but had no influence on the process ability of material.The extruding diameter of modified PP increased to 4.3mm that was 2 times more than raw PP,it was suggested that the long chain branching structure existed in modified PP.The capillary rheometer test showed apparent shear viscosity and viscous activity energy of modified PP increased obviously,the apparent shear viscosity of modified PP increased from 1340Pa.s to 8975Pa.s.The FTIR showed that the molecular structure was not changed during reactive extrusion. The DSC and WAXD showed that T_m and T_c increased obviously,β-crystalline had formed in modified PP.The mechanical property test showed that tensile strength and impact strength of modified PP increased obviously.更多还原