双转子连续混炼机制备插层型聚乙烯/有机蒙脱土纳米复合材料的研究

借助双转子连续混炼机,通过直接熔融插层法制备了聚乙烯/有机蒙脱土纳米复合材料,并用XRD测试了有机蒙脱土的层间距。分析了不同转子转速和喂料速率对聚乙烯有机蒙脱土复合材料层间距及其力学性能的影响。结果表明,选择适当的操作工艺以获得合适的剪切强度对于制备插层型聚乙烯有机蒙脱土纳米复合材料极为重要,当转子转速为400r/min,喂料速率为1.35kg/h时,制得的聚乙烯/有机蒙脱土复合材料层间距最大,插层效果最佳,有机蒙脱土的增强与增韧效果最好。     

直接注射制备聚丙烯／蒙脱土复合材料及其性能研究

采用直接注射法制备了聚丙烯／蒙脱土复合材料,考察了其材料结构与性能方面的特征,结果表明,蒙脱土可以在插层剂存在的条件下被插层,且其硅酸盐层片之间距离的变化完全取决于插层剂对蒙脱土的溶剂化作用,而和熔融混炼中热或机械能的作用无关;插层剂虽不能使非极性的PP分子本身对蒙脱土产生插层作用,但有助于使其易于分散在蒙脱土颗粒之间,使PP／蒙脱土复合体系中作为复合分散相的蒙脱土形成两种结构层次,第一种结构层次是被分散在PP树脂中的蒙脱土颗粒,第二种结构层次是处于蒙脱土颗粒中被插层剂等间隔地隔离开的多层硅酸盐片层,复合体系的冲击强度和硅酸盐层片层间距有良好的相关关系,插层剂添加量的增加,可以使PP／蒙脱土复合体系实现较好的增韧效果,但其拉伸强度将有一定程度下降。     

EVOH／有机蒙脱土插层复合材料的制备与表征

将经有机化处理过的蒙脱土与EVOH熔融共混制备插层复合材料，并对该复合材料进行了XRD分析，分析结果表明：聚合物基体已经插入了有机蒙脱土片层间；复合体系中蒙脱土含量越小，蒙脱土被插开的片层间距越大；当复合体系中有机蒙脱土含量≤8％时，形成剥离型复合材料；当有机蒙脱土含量在8％～15％时，形成插层型复合材料；当有机蒙脱土含量大于15％时，复合材料中蒙脱土片层间距无明显变化。对EVOH与蒙脱土熔融共混过程的扭矩分析表明：该复合材料熔融混合9min之后，达到均匀混合和完全塑化的状态。     

聚丙烯／有机蒙脱土复合材料的制备、结构及性能

以改性聚丙烯作增容剂，用熔融插层法制备了聚丙烯／有机蒙脱土复合材料，研究了有机蒙脱土对复合材料力学性能的影响，并用X射线衍射研究了复合材料的结构。结果表明：增容剂增加了聚丙烯与蒙脱土片层之间的作用力，使蒙脱土片层间距增大，在聚丙烯基体中分散更好，因而使聚丙烯／有机蒙脱土复合材料的缺口冲击强度大幅度提高，当蒙脱土含量达5％时，缺口冲击强度提高120％，并且拉伸性能下降不大，约下降5％，其中有机蒙脱土TJ4的增韧效果最好。     

不同结构聚苯乙烯/蒙脱土复合材料的熔体流动行为研究

分别将聚苯乙烯树脂(PS)与钠基蒙脱土(Na-MMT)和有机化蒙脱土(OMMT)通过熔融复合制备纳米黏土改性的复合材料。通过X射线衍射(XRD)对复合材料的微观结构进行了分析,采用HAAKE流变仪和熔体流动速率仪研究了复合材料的熔体流动行为。结果表明,Na-MMT在与PS熔融复合前后,其片层间距没有发生变化,PS分子链没有插入蒙脱土片层之间,所形成的是一种填充型复合材料。OMMT在熔融复合后,片层间距显著增大,与PS分子链形成了插层复合结构。蒙脱土含量相同时,PS/Na-MMT复合体系的熔体流动性能比PS/OMMT体系更好。研究认为,熔融复合过程中PS分子链的断链和2种复合材料结构上的差异是影响2种材料流动性能的主要因素。     

聚丙烯/蒙脱土纳米复合材料的制备与表征

利用固相剪切法使蒙脱土片层完全剥离,制备聚丙烯/蒙脱土(PP/MMT)纳米复合材料,通过X射线衍射、扫描电镜、力学性能的实验得出：用水做为膨胀剂可使蒙脱土的层间距胀大,有利于PP分子的插层和蒙脱土的剥离;固相剪切法和熔融过程使蒙脱土完全地层状剥离,均匀纳米级分散在聚丙烯基体中,沿流动方向取向; PP与用水处理过的有机改性蒙脱土复合材料的冲击强度由5.68 kJ/m2提高到了8.2 kJ/m2,大量提升了材料的冲击性。     

PVC/聚烯烃/蒙脱土纳米复合材料的制备与性能研究

将钠基蒙脱土(MMT)预先负载小分子单体丙烯酰胺(AM)和引发剂过氧化二异丙苯，然后与PVC／PE或PVC／PP在双辊上进行插层复合，制成了PVC／聚烯烃／蒙脱土纳米复合材料，对复合材料进行了表征。结果表明：吸附丙烯酰胺后蒙脱土的层间距有所增大，AM-MMT填充的复合材料属于插层型纳米复合材料，PP复合材料比PE复合材料更容易插层蒙脱土；纳米复合材料的拉伸强度和冲击强度都随AM-MMT用量的增加有一最大值；DSC显示插层效果较好的纳米复合材料的Tg较低。     

有机插层剂对聚酰胺6／MMT纳米复合材料制备的影响研究

以烷基胺、季铵盐和氨基酸作为有机插层剂与蒙脱土片层进行阳离子交换，制备出层间距不同的有机蒙脱土。采用熔融插层法和原位聚合法分别制备聚酰胺（R％）／蒙脱土（MMT）纳米复合材料，并利用XRD、FT-IR、TEM对有机蒙脱土及纳米复合材料进行结构表征。研究结果表明：用烷基胺、季铵盐和氨基酸有机插层剂改性的蒙脱土层间距由原来的1．25nm分别增大到3．21nm、3．99nm和1．82m；季铵盐有机插层剂更适用于熔融插层法制备PA6／MMT纳米复合材料，而氨基酸有机插层剂更适用于原位聚合法制备PA6／MMT纳米复合材料。     

有机蒙脱土的制备及性能表征

以天然蒙脱土(MMT)为原料,用季铵盐和氨基酸作为有机插层剂与蒙脱土层间的阳离子进行交换,优化反应条件(改性时间、温度和搅拌速率),制备出层间距不同的有机蒙脱土,用FT-IR、XRD、TEM及TG对产物进行表征.结果表明,4种有机插层剂都已进入蒙脱土的层间,蒙脱土的层间距由1.25 nm增加到1.82～4.05 nm,其中,以1631-Cl为插层剂,改性时间为4 h,改性温度为80 ℃,搅拌速率为300 r/min时,制得的有机蒙脱土层间距大且晶形良好.     

纳米有机蒙脱土改性SEBS/PP共混物的研究

通过熔融插层的方法将纳米有机蒙脱土（OMMT）与氢化苯乙烯-丁二烯-苯乙烯嵌段共聚物（SEBS）／聚丙烯（PP）共混制备得到SEBS／PP／OMMT复合材料。X射线衍射实验证明,复合材料SEBS／PP／OMMT5％、SEBS／PP／OMMT10％片层间距分别为4．17nm,3．91nm,说明聚合物插层进入OMMT片层之间,制备得到SEBS／PP／OMMT插层复合材料。采用锥形量热仪测试材料的阻燃性能,燃烧测试结果表明,SEBS／PP／OMMT复合材料具有比较低的热释放速率和质量损失速率,并且随着OMMT添加量增加,复合材料的热释放速率、峰值热释放速率和总热释放先显著降低最后趋于一个稳定值。综合力学测试结果表明,当有机蒙脱土质量分数为5％～10％时,该复合材料的综合性能最好。     

Effects of extrusion process,type and content of clays,and foaming process on the clay exfoliation in HMS PP composites

The use of a high melt strength polypropylene (HMS PP) matrix reinforced with layered clays could be very useful to improve the properties of materials produced with processes involving melt stretching, like foaming. The control of the particles structure, that is, the degree of exfoliation and the clay distribution in the polymeric matrix, is the key to achieve the desired properties. In this study, the effects of the extrusion process, the clay type and content, and the foaming process on the morphology of different HMS PP based composites are studied. Both, natural and organomodified clays were used. The extrusion process has a negative effect in the composites containing natural clays as their interlayer distance decreases as the number of extrusion cycles increases. On the contrary, this process improves the intercalation of the organomodified clays. However, in both composites the interlayer spacing decreases when the clay content increases. While a percolated network is formed in the composites containing organomodified clays, no network is formed with the natural clays. Finally, the effect of the foaming process has also been analyzed. The Improved Compression Moulding (ICM) route was used to produce the foamed materials. This technique subjects the materials only to a temperature and a pressure gradient without applying any other external forces that could contribute to the clay exfoliation. In this way, only the effects of foaming and melt stretching are observed. In both composites, an increase in the interlayer distance is observed when the materials are foamed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42828.     

Effects of toughening agents on the behaviors of bamboo plastic composites

Three kinds of reactive toughening agents of bamboo plastic composites are studied in this article. The bio‐fiber keeps high polarity for the hydroxyl groups of the surface, while polypropylene (PP) matrix resin phase is nonpolar. So, the interfacial compatibility between matrix and enhanced phase is poor. The anhydride in maleic anhydride grafted polypropylene can react with the hydroxyls. A large number of hydroxyl groups on the fiber surface are reduced, and the interfacial bond strength is improved. Three reactive toughening agents: glycidyl methacrylate grafted poly(ethylene‐1‐octene), maleic anhydride grafted poly(ethylene‐octene), and poly(ethylene‐butylacrylate‐glycidyl methacrylate) are chosen to improve the impact toughness. The mechanical properties, compatibility, phase structure, water absorption, and thermal properties of PP blends are all investigated. When the content of toughening agents are controlled between 6% and 8%, not only the impact strength is greatly improved but also the other properties of PP are less affected, which makes the composites with comprehensive and practical applications. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

不同增韧剂对PBT增韧改性的研究

利用双螺杆挤出机,采用聚乙烯-辛烯弹性体(POE)、聚乙烯-辛烯弹性体接技马来酸酐(POE-g-MAH)以及聚丙烯(PP)作为增韧剂与聚对苯二甲酸丁二醇酯(PBT)进行熔融共混,研究了不同增韧剂POE、POE-g-MAH和POE-PP对PBT共混物的力学性能、相容性和熔融结晶行为的影响。通过拉伸、冲击、熔体质量流动速率、硬度等性能测试以及红外光谱、X射线衍射仪(XRD)、差示扫描量热仪(DSC)等综合测试。结果表明,加入增韧剂对PBT具有良好的增韧效果,其中以PBT/POE/PP的增韧效果最明显。当PBT∶POE∶PP质量比为7∶3∶1时,共混物的缺口冲击强度增加8倍,红外表征显示,增韧改性可提高PBT的相容性,XRD测试表明,增韧剂对PBT复合材料的晶体结构没有影响,通过熔融增韧,提高其力学性能和加工性能。DSC图显示,增韧剂的加入可使共混物的结晶度降低。扫描电镜(SEM)表明,增韧剂的加入增加界面了结合力,提高了共混体系相容性。     

Preparation of polypropylene–clay nanocomposites by the co‐intercalation of modified polypropylene and short‐chain amide molecules

The effect of short‐chain amide (AM) molecules on the intercalation of montmorillonite clay has been investigated by the melt blending of polypropylene (PP) with clay in the presence of AM molecules such as 13‐cis‐docosenamide (erucamide). Polypropylene–clay nanocomposites (PPCNs) were prepared by the co‐intercalation of maleic anhydride grafted polypropylene (PP–MA) and an AM compound. The resulting nanocomposite structures were characterized with X‐ray diffraction (XRD) and transmission electron microscopy, whereas the thermal characterization of the PPCNs was conducted by thermogravimetric analysis. XRD results showed that the AM molecules intercalated into clay galleries and increased the interlayer spacing, a result confirmed by surface energy (contact angle) and melt flow index measurements. This additive allowed the formation of an intercalated nanocomposite structure, but an exfoliated PPCN structure was also formed with the use of AM with a PP–MA‐based compatibilizer. A new preparation method for PPCNs was, therefore, developed by the co‐intercalation of AM and PP–MA; this resulted in a significantly improved degree of intercalation and dispersion. The enhanced thermal stability of PPCN, relative to pure PP, further demonstrated the improved clay dispersion in the nanocomposite structures prepared by this method. A possible mechanism for the co‐intercalation of AM and PP–MA into the clay galleries is proposed, based on hydrogen bonding between these additives and the silicate layers. Consideration is also given to possible chemical reactions and physical interactions in this rather complex system. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

聚丙烯/稀土氧化物复合材料性能与微观结构

以稀土氧化镧(La2O3)和氧化铈(CeO2)为改性剂,聚丙烯(PP)为基体,通过熔融混合挤出制得PP/稀土氧化物复合材料。对该复合材料的力学性能、耐热性、流动性进行了测试和分析,采用扫描电镜对其微观结构进行观察,对稀土氧化物改性PP机理进行了讨论。结果表明,La2O3改性PP比PP基体力学性能、耐热性、流动性均有提升,CeO2对PP基体增韧效果明显。稀土氧化物粒子在复合材料中分散均匀、与PP相容性良好,稀土氧化物使PP得到有效增强增韧。     

加工方式对PP/EAA/LDH复合材料性能影响

进行了聚丙烯(PP)、乙烯–丙烯酸共聚物(EAA)及水滑石(LDH)复合材料改性一体化研究,并研究了一次熔融挤出加工法和二次熔融挤出加工法对PP复合材料性能的影响。X射线多晶衍射、透射电子显微镜分析表明:两种加工方法制备的复合材料中EAA均插层和剥离了LDH,改善了LDH在PP基体中分散性,并且一次挤出加工效果优于二次挤出加工效果;热失重分析表明,两种加工方式均提高了复合材料的热稳定性能;静态力学性能测试表明:一次挤出加工制备的复合材料PP1的拉伸强度、拉伸弹性模量和缺口冲击强度均高于二次挤出加工制备的复合材料PP2。实验表明一次熔融挤出加工方法对复合材料中LDH插层和剥离效果以及LDH在PP基体中分散效果优于二次熔融挤出加工。     

PP／PPMA／Org—MMT复合材料的制备与性能研究

采用熔融插层法制备PP／PPMA／Org-MMT复合材料，考察接枝物含量、不同聚丙烯、不同接枝率接枝物以及不同成型工艺对PP／PPMA／Org-MMT复合材料的制备与力学性能的影响。结果表明，采用PP（F401）、高接枝率接枝物和模压工艺可获得较好的插层效果。接枝物含量为10％时，PP／PPMA／Org-MMT复合材料的拉伸强度达到最大值。     

液态成型环氧树脂基复合材料增韧研究进展

总结了提高液态成型环氧树脂基复合材料韧性的三种方法,包括增韧树脂基体、层间增韧以及通过Z向增强来增韧。简要介绍了这三种方法各自的增韧机理、影响因素及优缺点。     

有机蒙脱土和氢氧化镁对PS的协同阻燃作用研究

将聚苯乙烯(PS) 树脂与有机蒙脱土(OMMT) 和表面改性的氢氧化镁(MH) 直接熔融复合制备了PS/MH/OMMT复合材料,采用X射线衍射对复合材料的微观结构进行了分析,分别用水平燃烧试验、氧指数试验和高温处理试验研究了复合材料的阻燃性能。结果表明：OMMT 与PS熔融复合后,其片层间距从1.46 nm增加至3.30 nm,表明与PS分子链形成了插层复合结构,MH的引入并不影响纳米插层结构的形成。OMMT与MH并用时可以显著减少复合材料在燃烧时的滴落和发烟性,材料在高温下更加稳定,阻燃性能更好,从而可以减少阻燃剂的用量。