聚酰胺6/连续碳纤维复合材料的结晶行为

利用自行设计的浸渍装置,通过熔融浸渍法制备了连续碳纤维增强聚酰胺6(PA6/LCF)复合材料。研究了LCF对PA6/LCF复合材料结晶行为的影响。结果表明,LCF的加入对PA6基体具有异相成核作用,增容剂苯乙烯马来酸酐共聚物(SMAH)和聚丙烯接枝马来酸酐(PP-g-MAH)的加入均能促进LCF对PA6基体的异相成核作用。PA6的等温结晶均相成核和异相成核共存,PA6/LCF复合材料则以异相成核结晶为主。非等温结晶研究表明,随着冷却速率的增加,PA6,PA6/LCF复合材料的结晶速率变大,半结晶时间降低。     

PA6/PP/SEBS-g-MAH共混物的相容性研究

采用马来酸酐接枝(氢化苯乙烯/丁二烯/苯乙烯)共聚物(SEBS-g-MAH)作为增容剂,研究了增容剂用量对尼龙6/聚丙烯(PA6/PP)共混体系相态结构、力学性能的影响,以及在相同增容剂用量下不同PA6、PP配比对体系相形态的影响。结果表明,SEBS-g-MAH中的酸酐基团能与PA6末端的氨基发生化学反应,在PA6和PP的内表面形成PA6-SEBS接枝共聚物,明显改善了两相的界面相容性,并使共混物的力学性能得到显著提高。共混物冲击断面形貌的分析表明,共混物发生了明显的脆韧转变。     

PA6/PPO共混物的非等温结晶动力学

采用差示扫描量热法研究了聚酰胺6/聚苯醚（PA6/PPO）共混物的非等温结晶动力学。通过Jeziorny法、Mo法分别对非等温结晶过程进行处理。结果表明,PPO对PA6结晶起促进作用,而马来酸酐接枝聚苯醚（PPO-g-MAH）、氢化聚苯乙烯-丁二烯-苯乙烯嵌段共聚物（SEBS）和SEBS-g-MAH对PA6的结晶起阻碍作用;随着冷却速率的增大,共混物的结晶度下降,半结晶时间减小;Jeziorny和Mo法都适合分析PPO/PA6的非等温结晶过程。     

接枝共聚物对聚丙烯/尼龙6共混物结构和性能的影响

采用4种接枝共聚物作为增容剂来提高PP/PA6共混物相容性.研究了不同类型接枝共聚物对PP/PA6共混物加工性能的影响,同时也探讨了接枝共聚物对PP/PA6共混物微观结构变化的影响.结果表明PP/PA6共混物为热力学不相容的海-岛型两相结构,接枝共聚物的加入改善了PP与PA6的相容性,使两相分散均匀,对PP/PA6共混物的性能具有一定的改善作用.     

EPT接枝共聚物的制备及其对PA6/EPT共混体系的增容作用

采用溶液接枝技术成功制备了可反应性相容剂——EPT接枝共聚物(EPT-g-ITA和EPT-g-MAH),红外光谱分析证明ITA、MAH已经成功接枝在EPT主链上。实验研究了引发剂和单体用量对接枝共聚物接枝率和凝胶含量的影响,当EPT/ITA/BPO=100/20/4时,接枝率达到3.16%,凝胶含量为8.8%;当EPT/MAH/BPO=100/8/0.64时,接枝率达到3.58%,凝胶含量为6%。通过双螺杆挤出机将EPT接枝共聚物引入PA6/EPT共混体系,当EPT-g-MAH/PA6含量为15%时,PA6/EPT/EPT-g-MAH共混物的缺口冲击强度比纯PA6提高了20倍。通过对EPT接枝共聚物的接枝率、凝胶含量以及PA6合金的缺口冲击强度等实验数据的分析可知,接枝在EPT主链上的MAH支链较短,接枝点较多;接枝在EPT主链上的ITA支链较长,接枝点较少。     

POE-g-MA对nano-CaCO3/PA66复合材料结构和性能的影响

通过双螺杆熔融共混法制备了纳米碳酸钙/马来酸酐接枝乙烯-辛烯共聚物/尼龙66(nano-CaCO3/POE-g-MA/PA66)三元复合材料,采用SEM、DSC和XRD等手段表征了材料的形貌和结构,研究了弹性体POE-g-MA的含量和物料共混顺序对nano-CaCO3/PA66(20/80)复合材料力学性能﹑加工性能和复合材料形貌的影响。研究表明,POE-g-MA与尼龙基体具有较好的相容性,能细微地分散在复合材料中。POE-g-MA能促进复合材料中PA66的结晶,有效改善nano-CaCO3/PA66复合材料的冲击性能﹑断裂伸长率和加工性能。与一步同时共混法相比较,nano-CaCO3先与PA66共混后再与POE-g-MA共混的二步共混法,更有利于提高nano-CaCO3的分散程度和nano-CaCO3/POE-g-MA/PA66(20/10/70)三元复合材料的综合力学性能。     

接枝POE增韧尼龙6的性能

研究了接枝POE增韧PA6及无水氯化锂增强POE接枝甲基丙烯酸环氧丙酯/尼龙6(POE-g-GMA/PA6)复合材料。结果表明:POE接枝甲基丙烯酸环氧丙酯(POE-g-GMA)对PA6具有很好的增韧效果,无水氯化锂在增强POE-g-GMA/PA6复合材料的同时,改变了PA6的结晶度和结晶形态,当氯化锂的添加量为5份时,可以得到无定形的PA6/POE-g-GMA/LiCl复合材料。     

碳纤维表面阴离子接枝尼龙6对CF/PA6复合材料界面形态的影响

研究了碳纤维(CF)表面阴离于接技尼龙6(PA6)对CF/PA 6复合材料界面形态的影响,考察了纤维表面、结晶温度对CF/PA 6复合材料界面形成横晶的影响.结果表明在低于初始结晶温度至接近熔点范围内,PA6在未接枝与接枝CF表面均可以形成横晶,结晶温度低形成的横晶不致密、不完整,纤维诱发横晶的能力小,结晶温度高形成的横晶完整而致密,纤维诱发横晶的能力大.在相对较低的结晶温度下,接枝CF比未接枝CF具有较高的诱发横晶能力,同时诱发的横晶致密度高及完整性好.     

高性能PA6/ABS合金的研制

分别以接枝ABS、苯乙烯-马来酸酐接枝物（SMA）和苯基马来酰亚胺共聚物为相容剂,考察了它们对PA6/ABS共混体系相容性和力学性能的影响。并研究了PA6/ABS共混体系中PA6、ABS树脂的选择对共混物冲击韧性的影响。研究表明,接枝ABS、SMA和苯基马来酰亚胺共聚物都是PA6/ABS共混体系的有效增容剂,能显著改善PA6/ABS共混物的相容性并提高共混物的机械力学性能。选用高粘度的PA6树脂有利于提高共混体系的冲击韧性,提高高胶含量ABS用量有助于获得高低温冲击性能优异的PA6/ABS合金材料。     

PA6T/1010共聚物热性能研究

以对苯二甲酸、己二胺和癸二酸、癸二胺为原料合成了新型半芳香PA6T/1010共聚物,通过差示扫描量热仪(DSC)、熔点测定仪和热重分析仪(TG)对不同组成PA6T/1010的熔融行为、结晶行为和热稳定性进行了表征。结果表明:当PA6T含量大于40%时,PA6T/1010共聚物的结晶性能明显下降,熔融峰和结晶峰均消失;当PA6T含量为40%时,共聚物共熔点降至165℃;PA6T/1010共聚物的热降解过程为一步降解,热降解温度超过400℃。     

PP-g-(MAH/VAc)接枝物对PP/PA6体系的增容作用

通过扫描电镜、差示扫描量热仪和力学性能测试等方法研究了聚丙烯接枝马来酸配和酷酸乙烯酷(PP-g-MAH/VAc)对聚丙烯康酸胺6(80/20}共混体系的增容效果。结果表明,PP-g-(MAH/DAc)用于PP/PA6共混体系,分散相PA6的微区尺寸可以减小到5μm以下,相应地提高了共混物的断裂伸长率、拉伸强度和冲击强度。使用接枝率为5.3%的PP-g-(MAH/VAc)作为相容剂,当用量为8%时,体系的拉伸强度为60.88MPa,断裂伸长率为558%,冲击强度为5.28KJ/㎡.DSC分析表明,PP/PA6共混体系各组分相互促进成核,结晶度降低。FTIR结果表明,PP-g-(MAH/VAc)中的MAH上的酸配基团与PA6中的酸胺键发生了化学反应从而改善了体系的相容性。     

PP固相接枝马来酸酐增容PP／PA6研究

以高速搅拌器为反应器,利用聚丙烯(PP)粉料自身摩擦生热,制备出不同接枝率的聚丙烯固相接枝马来酸酐(PP-g-MAH);通过对熔体流动速率测定、差热分析以及偏光显微分析,研究了PP-gMAH对PP／聚酰胺6(PA6)共混体系的增容作用及其对共混体系力学性能的影响。结果表明:采用固相法制备的PP-g-MAH可以明显提高PP与 PA6的相容性,PP-g-MAH接枝率高(1．2％)增容效果好;添加固相接枝PP-g-MAH的PP／PA6共混体系的拉伸强度和冲击强度高于添加熔融接枝物的PP／PA6共混体系。     

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.     

不同共混材料对尼龙6增韧改性的影响

为提高尼龙6(PA6)的力学性能,采用共混处理的方法,在一定的比例下,将PA6分别与乙烯-辛烯共聚物(POE)、接枝弹性体、纳米级纳普橡胶颗粒进行共混,与接枝弹性体和纳米级纳普橡胶颗粒同时进行共混,以共混后力学参数的测试结果为依据,对不同共混材料相界面的结合力进行了物理结合与化学交联的分类,对PA6在受力状态下空穴化理论"多孔结构"模型说给以了实验的支持,比较分析了不同共混材料对尼龙6增韧改性的影响,从一个方面指出了对PA6进行增韧改性的方向。     

One-step compatibilization of polyamide 6/ poly (ethylene-1-octene) blends with maleic anhydride and peroxide

Polyamide 6/poly(ethylene-1-octene) (POE) blends were prepared in the presence of both maleic anhydride and peroxide via melt blending. The intrinsic viscosity, mechanical properties, rheology, and phase morphology of blends were evaluated. Molau test was adopted to confirm the formation of a graft copolymer between PA 6 and POE, rheology property also indicated the graft reaction. The SEM analysis showed a significant reduction in particle size of seperation phase after one-step compatibilization. It provides a promising method to obtain toughened polyamide material.     

Poly(styrene-graft-ethylene oxide) as a compatibilizer in polystyrene/polyamide blends

Polystyrene (PS) blends containing a dispersed phase of either polyamide-6 (PA-6) or polyamide-12 (PA-12) were compatibilized by additions of 1, 3, or 5 wt % poly(styrene-graft-ethylene oxide). The graft copolymers were found to have a stabilizing effect on the domain sizes. Weight average radii of PA-6 domains in compression molded samples were reduced by a factor of 5 with 3 wt % graft copolymer added. The corresponding size reduction for PA-12 domains was by a factor of 3. Also, the domain sizes were more uniformly distributed in blends containing the graft copolymers. Thermal analysis of the blends revealed that compatibilization retarded the PA crystallization, with some PA crystallizing at the PS glass transition. This retarded crystallization is explained as a result of the domain size reduction and by the presence of graft copolymer at the interface. The graft copolymers had a toughening effect on the blends and the impact strength of a PS/PA-12 blend was improved by 65% by adding 3 wt % of graft copolymer. Binary blends of the PA and poly(ethylene oxide) (PEO) were investigated in a separate study to verify miscibility of the graft copolymer side chains and the PA. Hydrogen bonding between PA-6 and PEO was confirmed by IR spectroscopy and partial miscibility was indicated by melting point depressions. © 1995 John Wiley & Sons, Inc.     

Compatibilization of PS and PA6 Blends by Means of Poly(oxyalkylene)amine Modified Styrene-Maleic Anhydride Copolymer

The compatibilization effect of SMA-co-M2070-co-DAP comb-like copolymers, SMMD, on immiscible blends of polystyrene (PS) and polyamide-6 (PA6) is examined in terms of phase structure, thermal behavior, dynamic mechanical analysis, and mechanical properties. A series of SMMD copolymers are synthesized and confirmed by the FT-IR analysis. These compatibilizers have different amphiphilic properties depending on the content of hydrophilic poly(oxyethylene) segments (M2070) and the molar ratio of MA/amine. The morphologies of PS/PA6, affected by the increasing amount of SMMD compatibilizer, show a more regular and finer dispersion. The sizes of dispersed particles have no marked changes over the saturation level of compatibilizer. The glass transition temperatures of the blends are between that of PS and PA6, while the added SMMD copolymer is mainly located at the interface. Using these SMMD copolymers, the compatibilized blends show some improvements in mechanical properties, including Izod impact strength and flexural properties. The graft poly(oxyethylene) and amide functionalities in SMMD structures in forming hydrogen bonding with PA6 and, the polystyrene backbone in π–π interaction with PS facilitate the compatibilizing effect.     

Poly(ethylene‐graft‐ethylene oxide) (PE‐PEO) and poly(ethylene‐co‐acrylic acid) (PEAA) as compatibilizers in blends of LDPE and polyamide‐6

In a blend of two immiscible polymers a controlled morphology can be obtained by adding a block or graft copolymer as compatibilizer. In the present work blends of low‐density polyethylene (PE) and polyamide‐6 (PA‐6) were prepared by melt mixing the polymers in a co‐rotating, intermeshing twin‐screw extruder. Poly(ethylene‐graft‐polyethylene oxide) (PE‐PEO), synthesized from poly(ethylene‐co‐acrylic acid) (PEAA) (backbone) and poly(ethylene oxide) monomethyl ether (MPEO) (grafts), was added as compatibilizer. As a comparison, the unmodified backbone polymer, PEAA, was used. The morphology of the blends was studied by scanning electron microscopy (SEM). Melting and crystallization behavior of the blends was investigated by differential scanning calorimetry (DSC) and mechanical properties by tensile testing. The compatibilizing mechanisms were different for the two copolymers, and generated two different blend morphologies. Addition of PE‐PEO gave a material with small, well‐dispersed PA‐spheres having good adhesion to the PE matrix, whereas PEAA generated a morphology characterized by small PA‐spheres agglomerated to larger structures. Both compatibilized PE/PA blends had much improved mechanical properties compared with the uncompatibilized blend, with elongation at break (ε_b) increasing up to 200%. Addition of compatibilizer to the PE/PA blends stabilized the morphology towards coalescence and significantly reduced the size of the dispersed phase domains, from an average diameter of 20 μm in the unmodified PE/PA blend to approximately 1 μm in the compatibilized blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2416–2424, 2000     

接枝聚丙烯增容改性PP/PA合金性能的研究

用PP接枝物增容PP/PA6共混体系,观察分析了共混合金的形态结构特点,测试了共混物的力学性能.结果表明：单独加入PP-g-MAH,力学性能均呈现先升后降的趋势,峰值时拉伸强度比未加接枝物时可提高20%,弯曲强度比未加接枝物时提高了54%,冲击强度比不添加接枝物时提高了3.6%.添加PP-g-MAH对不同比例PP/PA6共混物力学性能的影响不同,固定PP-g-MAH用量为4%,PA6质量分数为30%时共混物的综合力学性能达到最好.用PP-g-MAH和PP-g-GMA两种接枝物共同作为相容剂加入到PP/PA6共混物中比单独使用一种的效果要好,拉伸、弯曲和冲击强度都得到显著的提高.由共混物的SEM照片可以看到,PP-g-MAH使分散相的粒径变小,分布均匀,界面相互作用加强,所以是PP/PA6共混物的有效增容剂.     

马来酸酐(MAH)接枝SEBS及其对PPO/PA6合金性能的影响

利用红外光谱测定了接枝样品,用其中马来酸酐(MAH)的特征峰与苯乙烯/乙烯/丁烯/苯乙烯嵌段共聚物(SEBS)的特征峰之比值来表达接枝率,探索了接枝时MAH和助剂的量对接枝率的影响,同时探讨了不同接枝率的相容剂及不同比值的聚苯醚(PPO)/尼龙6(PA6)对PPO/PA6合金的增容作用及其对合金的综合性能影响.结果表明:(1)加入合适的助剂有利于SEBS体系的接枝,而当MAH的加入量为3%时得到的接枝率最高;(2)接枝率提高,合金的综合性能稍有改善;(3)PPO/PA6 = 70/30时性能指标达到最优.而接枝的SEBS加入量10%时PPO/PA6合金的综合性能最优.