PS/PA6聚合物纳米合金的制备--共混方法对聚合物纳米合金的影响

用原位聚合/原位增容的方法,成功地制备了PS/PA6的纳米复合物。通过不同的共混方法发现,直接将PS和CL共混时,由于物料在混炼机中分布不均匀,很难得到分散均匀的纳米共混物;如果先将两者制成均匀的溶液而后再共混、聚合,则可以得到分散相粒径分布均匀的PS/PA6纳米复合物。     

PS-g-PA6制备及在PS/PA6体系的相容作用

利用苯乙烯（St）和3-异丙烯基-α，α-二甲基苄基异氰酸酯（TMI）的共聚物为起始剂，在催化剂己内酰胺钠（NaCL）存在下，TMI中异氰酸官能团引发己内酰胺（CL）聚合，合成了接枝共聚物PS-g-PA6。进-步研究了相容剂PS-g-PA6存在下聚苯乙烯（PS）和尼龙6（PA6）共混体系的形态结构。结果表明：不论母体PS和分散相PA6的比例如何，只需少量的PS-g-PA6就可大幅减小分散相PA6的粒径。对于PS／PA6（90／10）共混体系，仅需加入1．50％（质量分数）的PS-g-PA6，分散相的粒径从没有加PS-g-PA6的2．5μm减小至0．3μm。     

原位聚合法制备马来酸酐化EPDM/PA6共混型热塑性弹性体

采用电子同步转移反应（Ene Reaction）制备了马来酸酐化EPDM（EPDM—g—MAH），并在EPDM—g—MAH中原位聚合己内酰胺生成尼龙6（PA6）制备了EPDM—g—MAH／PA6共混型热塑性弹性体。采用X-射线衍射法（XRD）和差示扫描量热法（DSC）研究了原位聚合法和直接共混法制备的EPDM—g—MAH／PA6共混体系的结晶行为。研究表明，230℃下进行阴离子聚合得到的PA6为β-介晶型；EPDM对这种分散在橡胶相中的PA6的结晶具有异相成核作用；原位聚合可在反应增容的基础上使得共混物中PA6的结晶焓进一步降低。动态力学分析频率谱研究表明，增容和原位聚合在削弱PA6组分对刚度贡献的同时可提高橡胶相的弹性响应。     

ACS/Sb2O3复合材料制备方法对性能的影响

对采用原位悬浮聚合制备的苯乙烯一氯化聚乙烯一丙烯腈（ACS）共聚物／Sb2O3复合树脂、原位聚合苯乙烯一丙烯腈（SAN）共聚物／Sb2O3复合树脂与ACS树脂的共混物和ACS树脂／Sb2O3的直接共混物的力学性能和阻燃性能进行了研究比较。结果发现：原位聚合法制备的ACS／Sb2O3复合材料的性能优于其它两种方法制备的复合物；三种复合材料的冲击性能都劣于纯ACS材料；采用原位聚合方法，Sb2O3质量分数小于7％时，Sb2O3对复合材料有增强作用；当Sb2O3质量分数大于10％时，直接共混ACS／Sb2O3复合物的阻燃性能劣于其它两种方法制备的ACS／Sb203复合材料。     

聚合物共混体系原位增强机制的形成与强化

简述了热塑性聚合物共混物原位复合材料的研究进展及意义，总结了如原位复合材料的化学组成、物理特性及成型工艺对分散相“原位”成纤及其性能的影响，重点叙述了相容性对材料力学性能及拉伸、剪切作用对分散相原位成纤的影响．并提出了，磁场作用促进共混体系中分散相聚合物分子链取向及与流场协同作用的思路。     

PET／TLCP原位共混的研究

研究了PET／TLCP原位共混体系的热性能、流变性能、力学性能。结果表明，在PET中加入少量TLCP可起到结晶成核剂的作用，提高PET基体的结晶性能，并使共混物的熔体粘度降低；催化剂二月桂酸二丁基锡的加入，可增加共混物的熔体粘度，降低分散相的尺寸，增强共混物两相间的界面粘接，从而提高PET／TLCP共混体系的力学性能。     

磺酸掺杂聚苯胺导电复合材料的研究进展

就化学原位聚合、溶液共混、熔融共混制备磺酸掺杂聚苯胺／聚合物导电复合材料的研究进展作一综述，简述了各种方法的优缺点和目前的应用情况。     

三维编织碳纤维尼龙复合材料的研究

根据碱催化阴离子聚合原理，用液态原位聚合方法制备了尼龙／三维编织碳纤维复合材料（PA／C3D），介绍其成型工艺过程，测试并分析了PA／C3D复合材料的力学性能及影响因素。结果表明，PA／C3D复合材料具有比长碳纤维增强尼龙（PA／CL）复合材料高的冲击强度和剪切强度，其弯曲性能低于PA／CL复合材料。碳纤维空气氧化处理后制备的PA／C3D复合材料的弯曲强度、弯曲弹性模量及平面剪切强度均有所提高，但冲击强度下降。     

PVC/无机纳米复合材料的研究进展及应用

介绍了共混法、原位聚合法和插层聚合法制备PVC／无机纳米复合材料的方法，概述了其力学性能、热稳定性和阻隔性等性能的研究进展及应用。     

原位聚合PLA/HA复合材料的性能研究

采用原位聚合法和超声波辅助分散溶液共混法，分别制备了羟基磷灰石质量分数为30％的聚乳酸（PLA）／羟基磷灰石（HA）生物可降解复合材料，对其结构与力学性能进行了研究。结果表明，HA的存在对乳酸的聚合有一定的影响，使其摩尔质量降低、分布变宽。与共混法相比，原位聚合法改善了HA在复合材料中的分散性，在PLA与HA之间形成了较强的结合界面，从而提高了PLA玻璃化温度和力学性能。     

Novel morphologies of poly(phenylene oxide) (PPO)/polyamide 6 (PA6) blend nanocomposites

Poly(phenylene oxide) (PPO)/polyamide 6 (PA6) (50/50 w/w) blend nanocomposites were prepared by melt mixing of PPO, PA6, and organically modified clay. The morphology of PPO/PA6 nanocomposite with various amounts of clay has been investigated using scanning electron microscope (SEM), transmission electron microscope (TEM), and wide-angle X-ray diffraction (WAXD). For the PPO/PA6 blend without clay, PPO is dispersed in the PA6 matrix with an average particle diameter of about 4.2 μm. The domain size of the dispersed PPO phase is significantly decreased to about 1.1 μm by adding a small amount of clay (2%). However, when the amount of organoclay is more than 5%, the matrix-domain structure is found to transform into the co-continuous morphology. The TEM observation shows that all the organoclay is dispersed only in the PA6 phase with a high degree of exfoliation and there is no any clay detectable in the PPO phase for the nanocomposites regardless of the amount of clay. It is considered that the dispersed clay platelets play an important role in the control of the PPO/PA6 blend morphology. Firstly, the selective localization of clay in PA6 phase changes the viscosity ratio of the PPO and PA6 phases. Therefore, clay has significant effects on the morphology of the polymer blend. Secondly, the high aspect ratio of the clay platelets prevents the coalescence of domains during melt mixing.     

Novel Polyamide 6/Polystyrene In Situ Microfibrillar Blends Prepared by Anionic Polymerization of ε‐Caprolactam via Reactive Extrusion

In this study, polyamide 6/polystyrene in situ microfibrillar blends are prepared via anionic polymerization of ε‐caprolactam in a twin screw extruder. Scanning electron microscope analysis reveals that microfibrillated PA6 dispersed phase, which is continuous and preferentially oriented parallel to the extrusion direction, is in situ formed within polystyrene (PS) matrix during reactive extrusion at the content PS equal to 30 and 40 wt%. Mechanical properties analysis shows that the yield strength and elongation at break of PA6/PS (70/30 and 60/40) microfibrillar blends are remarkably increased with respect to those of pure PS. Also, the in situ fibrillation mechanisms are investigated by the analysis of morphological evolution. This work demonstrates a facile and efficient route to fabricate the microfibrillar blends with relatively high contents of polymer microfibrils.

     

From polymer blends to in situ polymer/polymer composites: Morphology control and mechanical properties

In situ polymer/polymer short fiber composites were generated by a two‐step process. In the first step, a polyamide (PA) dispersed phase is blended with a polypropylene (PP) matrix in a twin‐screw extruder at a temperature at which both polymers are in molten state. The extrudate was then stretched at the die exit to generate long and thin fibers of PA in the PP matrix well oriented in the direction of flow. Adhesion between the phases was promoted by addition of PP grafted with maleic anhydride (PP‐g‐MA). During the second step, the chopped extrudates were molded by injection or compression molding at a temperature at which PA in the form of fibers is in the solid state and the PP matrix is molten. The control of the formation of such ultrafine fibers was obtained by quantitative analyses for the deformation of the minor PA‐phase during twin‐screw extrusion and stretching at the exit of the die that involve both shear and extensional flows. Morphology and mechanical properties of such polymer/polymer composites were compared to equivalent blends with dispersed spherical particles‐type morphology prepared in a batch mixer device.     

Effect of morphology on the electric conductivity of binary polymer blends filled with carbon black

Several carbon black (CB)‐filled binary polymer blends were prepared in Haake rheometer. Distribution states of CB and effect of morphology on the electric conductivity of different ternary composites were investigated. Under our experimental condition CB particles located preferentially at the interface between polymethyl methacrylate (PMMA) and polypropylene (PP) in PMMA/PP/CB composites, in high‐density polyethylene (HDPE) phase in PP/HDPE/CB composites, and in Nylon6 (PA6) phase in polystyrene (PS)/PA6/CB, PP/PA6/CB, PMMA/PA6/CB, and polyacrylonitrile (PAN)/PA6/CB composites; the ternary composites in which CB particles locate at the interface of two polymer components have the highest electric conductivity when the mass ratio of the two polymers is near to 1 : 1. The ternary composites in which CB particles located preferentially in one polymer have the highest electric conductivity usually when the amount of the polymer component having CB particles is comparatively less than the amount of the polymer component not having CB particles; if the formulations of PS/PA6/CB, PP/PA6/CB, and PMMA/PA6/CB composites equaled and PA6/CB in them is in dispersed phase, PS/PA6/CB composites have the highest electric conductivity and PP/PA6/CB composites have the lowest electric conductivity; suitable amount of PS or PAN in PA6/CB composites increase the electric conductivity due in the formation of a parallel electrocircuit for electrons to transmit. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Influence of in situ compatibilization on in situ formation of low‐density polyethylene/polyamide 6 blends by reactive extrusion

Low‐density polyethylene/polyamide 6 (LDPE/PA6) blends were in situ formed by reactive extrusion, in which in situ polymerization of ε‐caprolactam (CL) and in situ copolymerization of maleic anhydride grafted low‐density polyethylene (LDPE‐MA) and CL took place simultaneously. The latter reaction could be considered as in situ compatibilization, and the influence of in situ compatibilization on the morphologies, thermal properties, and rheological behaviors of the blends was investigated in this work. Scanning electron microscopy showed that the in situ compatibilization could dramatically reduce the dispersed phase sizes and narrow the size distribution. The thermal properties indicated that in differential scanning calorimetry (DSC) cooling scans, fractionated crystallization of the PA6 component was observed in all cases and was promoted with increasing the amount of LDPE‐MA. The DSC second heating scans showed the in situ compatibilization could stimulate the formation of the less stable γ‐crystalline form of PA6 in the blends. Dynamic rheological experiments revealed the in situ compatibilization had enhanced the viscosity, storage modulus, and loss modulus of the blend and reduce the corresponding slope values of the storage modulus and loss modulus. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Compatibilizing efficiency of copolymer precursors for immiscible polymer blends

An anhydride‐terminated polystyrene (PS‐b‐Anh) as a block copolymer precursor and a copolymer (PS‐co‐TMI) of styrene (St) and 3‐isopropenyl‐α,α‐dimethylbenzene isocyanate (TMI) as a graft copolymer precursor are chosen to investigate the effect of the type of the copolymer precursor on its compatibilizing and stabilizing efficiency for polymer blends. Results show that during the melt blending of the PS and PA6, the addition of PS‐b‐Anh dramatically decreases the size of the dispersed phase domains, irrespective of its molecular weight. This indicates that a diblock copolymer PS‐block‐PA6 (PS‐b‐PA6) is formed by a reaction between the terminal anhydride moiety of the PS‐b‐Anh and the terminal amine group of the PA6. When PS/PA6 (30/70) blends are annealed at 230°C for 15 min, their morphologies are much more stable in the presence of the PS‐b‐Anh block copolymer precursor than in the presence of the PS‐co‐TMI graft copolymer precursor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

丁腈橡胶/聚酰胺热塑性弹性体的制备及性能

采用Haake密炼机工艺、开炼机工艺和开炼机预混-Haake密炼机工艺制备了丁腈橡胶（NBR）／聚酰胺（PA）热塑性硫化胶（TPV）,研究了NBR／PATPV的结晶结构及其性能。结果表明,采用开炼机预混-Haake密炼机工艺可制得相态结构均匀、分散相粒径较小、力学性能和耐溶剂性能较好的NBR／PATPV。在NBR／PATPV中,NBR可诱发PA结晶。PA连续相结晶结构分布的均匀性和相界面之间的相互作用是提高NBR／PATPV耐溶剂性能的主要因素。     

Confined crystallization phenomena in immiscible polymer blends with dispersed micro - and nanometer sized PA6 droplets, part 1: uncompatibilized PS/PA6, (PPE/PS)/PA6 and PPE/PA6 blends

In this paper the crystallization behavior of PA6, dispersed as droplets in various immiscible amorphous polymer matrices, is reported. PA6 was melt-mixed at various compositions with PS, (PPE/PS 50/50 wt/wt) and PPE using twin-screw extrusion. The phase morphologies of the obtained blends were analysed using SEM, etching experiments and image analysis. The crystallization behavior of PA6 was investigated by dynamic and isothermal DSC experiments. In case PA6 is dispersed as droplets, fractionated crystallization behavior occurs, characterized by several crystallization events at different, lowered crystallization temperatures. It is found to depend on the blend morphology (size of the droplets) and the thermal history of the samples (heterogeneous nucleation density). The PA6 droplet size distribution is shown to strongly influence the crystallization behavior of the droplets. Vitrification of the matrix appears to cause nucleation in the droplets at the interface. Decreasing the PA6 droplet size results in slower overall crystallization rates.     

Structure,Morphology and Properties of a Novel Molecular Composite by In‐Situ Blending of Anionic Polyamide 6 with a Polyamide Copolymer Containing Rigid Segments

Molten caprolactam, in which a polyamide copolymer (HPN) containing rigid segments was dissolved, was polymerized by means of anionic ROP to in produce polyamide (PA, nylon) 6 blends with HPN in situ. A novel molecular composite was achieved in which toughness and strength were simultaneously improved, as well as modulus, compared to virgin PA6. In view of the interchange reaction between PA6 and PA1212 (and PA66) in blends fabricated in the same way, it was deduced that a similar reaction between PA6 and HPN took place during the blending and led to copolymerization between the two components. The formation of copolymers was verified by their single glass transition and single melting peak, measured through DMA and DSC, respectively. DSC analysis also showed that the occurrence of the interchange reaction inhibited the crystallization and suppressed the melting point of PA6. Analysis by FT‐IR spectroscopy indicated that the difference in the distance between the amide groups for PA6 and HPN induced a decrease in the amount and strength of hydrogen bonding. Moreover, characterization by POM and XRD revealed that the spherulite size of the PA6 crystals decreased dramatically and the amount of γ crystal increased slightly with the majority of crystallites being α crystals. Furthermore, it was found through the observation of the morphology by SEM that no phase separation existed in the composites. On the basis of detailed analysis and a comparison between the in situ PA6/PA66 and PA6/HPN blends, it is believed that the combination of markedly decreasing spherulite size and similar segmental mobility resulted in the simultaneous improvement of mechanical properties for the in situ PA6/HPN blends.

     

Blending PP with PA6 industrial wastes: Effect of the composition and the compatibilization

Blending polypropylene to recycled PA6 industrial wastes at different compositions, with and without compatibilizer PPgMA was produced in a corotating twin screw extruder where, polypropylene acts as the polymer matrix and polyamide as the dispersed phase. Several techniques were used to investigate the morphology, thermal, viscoelastic and tensile properties of these blend. Binary PP/PA6 blends showed the presence of PA6 particles dispersed in the PP continuous phase and exhibited a coarse morphology. Increasing PA6 contents in the blend increased their crystallinity and their size and improved the tensile properties at weak deformation. In addition to compatibilizer PPgMA, the morphology shows lower diameters and a decrease in size of the dispersed PA6 particles. The interfacial adhesion was also improved, as a result of the creation of an interphase that was formed by the interaction between the formed PPgPA6 copolymer in situ and both phases. This interphase induced an improvement in tensile properties. The PPgPA6 copolymer generated by the interphase was identified with DMA analysis thanks to an additional transition in loss modulus curves. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008