加工条件对聚丙烯/尼龙6原位成纤复合材料的影响

分别用不同的加工温度、挤出螺杆转速、牵引速率在单螺杆挤出机中挤出PP／N6（聚丙烯／尼龙6）共混物，得到不同加工条件下的PP／N6原位成纤复合材料．对不同加工条件下得到的共混物的分散相形态、力学性能进行研究．发现螺杆转速越高、牵引速率越快、加工温度越低，分散的N6纤维尺寸越小，复合材料的力学性能越好．     

毛细管流变仪中尼龙6在聚丙烯中的原位成纤

将聚丙烯与尼龙6的共混物在毛细管流变仪中挤出，通过显微形态观察发现，在研究的共沸比范围和较宽的剪切速度和温度范围内尼龙6均能在聚丙烯基体中成纤，表明这种热塑性树脂的成纤性比热致液晶聚合物的更好。     

聚丙烯/尼龙6/聚丙烯接枝物原位复合材料的形态与力学性能——共混过程对体系的影响

聚丙烯／尼龙６／聚丙烯接枝物原位复合材料的形态与力学性能———共混过程对体系的影响黎学东陈鸣才黄玉惠丛广民（中国科学院广州化学研究所广州５１０６５０）关键词原位复合材料，成纤，相容性原位成纤复合材料是指在加工过程中增强相在基体中就地形成微纤，不...     

聚丙烯／尼龙6原位复合材料的形态与表面,界面特性

以聚丙烯为基体、尼龙６为分散相共混得到分散相成纤的原位复合材料。显微形态观察发现在考察的浓度范围内微纤的直径基本与分散相含量无关。提高拉伸作用和增大剪切作用使微纤变细。当分散相含量越大，纤维数目越多时，水在复合材料表面的接触角越小，材料的吸水率越高。     

混合方式对增容尼龙-6/聚苯醚体系的影响

研究了三种混合方式对于Nylon 6 PPO TPEg共混体系的影响 .混合是在双螺杆挤出机上进行的 .即(A)尼龙 6、聚苯醚和TPEg的混合物直接进行熔融挤出 ;(B)尼龙 6与TPEg的混合物预挤出 ,然后与聚苯醚熔融挤出 ;(C)聚苯醚和TPEg的混合物预挤出 ,然后与尼龙 6熔融挤出 .实验结果表明 ,混合方式不仅会影响共混物的形貌结构 ,而且会影响复合材料的最终性能 ,如力学性能、热性能和尺寸稳定性 .采用混合方式C所得的尼龙 6 聚苯醚复合材料的抗冲击强度高于用混合方式A和B所制备的复合材料 .这是因为聚苯醚和TPEg预共混时 ,聚苯醚上的OH基团和TPEg上的一部分马来酸酐发生化学反应 .然后预混物和尼龙 6熔融挤出时 ,剩下的马来酸酐再与尼龙分子上的NH2 基团反应 .这样就会形成一个好的界面层 ,它使复合材料的抗冲击强度大幅度提高 ,材料达到了超高韧性     

微纤形态结构对PP/PA66原位微纤复合材料流变性能的影响

利用三角形排列三螺杆挤出机(triangle arrayed triple-screw extruder,TTSE)低温原位拉伸直接挤出制备了聚丙烯/聚己二酰己二胺(PP/PA66)原位微纤复合材料.通过三螺杆挤出机内部高强度的剪切-拉伸流场,研究了不同工艺参数如PA66含量、加工温度和螺杆转速下原位微纤复合材料中纤维的直径和长径比,并分析微纤长径比对复合材料动态流变性能的影响,且着重探究微纤长径比对凝胶点形成的影响.形貌分析结果显示,工艺条件极大地影响了微纤形貌,且PA66微纤长径比随分散相含量和螺杆转速的提高逐渐增加;动态流变数据说明,随着微纤长径比的增加,复合材料低频下的储能模量明显提高且比纯PP要高,同时,低频下的损耗角正切值降低且变化趋于平缓,而Cole-Cole圆半径显著增大,此时微纤复合材料表现出类凝胶的流变行为;原位微纤自缠结形成凝胶网络,微纤长径比越大,形成临界凝胶网络所需的PA66微纤含量越低,当长径比为210时,形成凝胶点时微纤含量仅3.80 wt%.     

微层共挤出(PP+EVOH)/PP阻隔材料的结构与性能研究

利用微层共挤出技术制备了具有交替层状结构的(PP+EVOH)/PP复合材料,其中PP为聚丙烯,EVOH为乙烯-乙烯醇其聚物.通过扫描电子显微镜观察、气体渗透实验、差示扫描量热仪分析以及力学性能测试研究了微层共挤出复合材料的形态结构及其对复合材料气体阻隔性能、力学性能以及结晶性能的影响.研究结果表明,通过微层共挤出技术,PP层和(PP+EVOH)层沿挤出方向交替排列,EVOH在PP基体中的的分散形态由零维球形变为一维纤维状,进而演变为二维片状.这些形态导致微层共挤出材料的氮气渗透系数和断裂伸长率较普通共混物分别下降了两个数量级和提高了27倍,并且显著影响其结晶行为.当层数超过64层后,由于PP层减薄,界面增多,EVOH不仅对(PP+EVOH)层中PP相存在结晶成核作用,而且对PP层也有结晶成核作用.     

拉伸温度和退火对尼龙6力学性能的影响

尼龙6(P6)制品在使用过程中受环境温度和应力作用后结构可能发生变化从而影响性能.把注射成型的P6哑铃型样品进行退火,利用拉伸热台在不同温度下拉伸得到退火前后样品的应力-应变曲线.通过对应力-应变曲线分析得到了退火前后尼龙6的力学性能.包括杨氏模量、屈服强度、屈服应变随拉伸温度的变化规律,并对实验结果进行了分析讨论.结果表明,退火后尼龙6的力学性能有了明显地提高.     

滑石粉及混炼顺序对PA6/PP/MAPP合金相形态及力学性能的影响

通过挤出和注射成型制备了滑石粉(Talc)填充的尼龙6/聚丙烯/马来酸酐接枝聚丙烯(PA6/PP/MAPP)合金, 研究了Talc和混炼顺序(一步法和PA6母料法)对合金相形态和力学性能的影响. 场发射扫描电镜(FESEM)分析结果表明, 添加Talc后注射样条中心部分的PP相由球状转变为沿流动方向取向的有分支的条状结构, 且用PA6母料法制样比用一步法制样的相形态更为精细. 溶解PA6相后对PP相进行热重分析(TGA), 确定了Talc在PA6相和PP相中的分布比例, Talc选择性分布于PA6相中. PA6母料法中Talc的分散好于一步法. 研究了材料的拉伸、 弯曲、 冲击、 热变形温度和动态力学性能, Talc的添加能够明显提高材料的刚性, 且母料法样品的性能优于一步法样品.     

预辐射聚丙烯反应挤出接枝丙烯酸的研究

利用电子束(EB)预辐照方法和反应挤出技术制备了聚丙烯接枝丙烯酸共聚物PP-g-AA. 采用化学滴定、红外光谱、偏光显微镜(PLM)、DSC和广角X射线衍射(WAXD)对接枝产物进行了表征. 研究结果表明, 接枝率随辐照剂量增加而增大并逐渐达到平台值, 但随单体浓度增大而表现为线性增加, 接枝链能起到异相成核作用, 从而提高了结晶速率并细化了球晶. 同时, 熔体流动速率(MFR)和力学性能测试结果表明, 预辐射和挤出过程造成了PP严重降解, 据此可认为接枝反应主要发生在聚丙烯断裂分子链的末端.     

MORPHOLOGY AND MECHANICAL PROPERTIES OF POLYPROPYLENE WITH in situ FORMED POLYAMIDE-6 FIBRILS

in situ Fibril formation of polyamide-6(PA6)in isotropic polypropylene(iPP)was first fabricated using a slit die extrusion and hot stretching process.Then the prepared materials were subjected to injection molding in the temperature range higher than the melting temperature of iPP but lower than that of PA6.The obtained injection-molded samples were characterized via scanning electron microscopy(SEM),differential scanning calorimetry(DSC)and two-dimensional wide- angle X-ray scattering(2D-WAXS).Mechanical properties were also investigated.The SEM result shows that the optimum fibril formation could be only achieved in the range of 20 wt% to 30 wt% of PA6 content for the studied system.The fibril morphology changes along the sample thickness in the injection-molded bars.The fibril morphology in the skin layer was better than that in the core layer.2D-WAXS results showed that the orientation of PP decreased with the increase of PA6 content,which indicated that the orientation of PP was confined by PA6 fibrils.Combined consideration of mechanical properties and morphology indicates that only PP/PA6 composites with 20 wt% of PA6 content show better properties because of the better fibril morphology and PP chain orientation.     

PP-g-(GMA-co-St)对PA6/PC共混物的反应增容作用

用红外、扫描电镜、熔体流动速率和力学性能等测试方法,研究了甲基丙烯酸缩水甘油酯(GMA)和苯乙烯(St)多单体熔融接枝聚丙烯[PP-g-(GMA-co-St)]对PA6/PC共混物的反应增容作用.研究结果表明,在熔融共混过程中,PP-g-(GMA-co-St)中的环氧基与PA6的端氨基及PC的端羟基原位生成的接枝共聚物有效地降低了共混物相间的界面张力,明显提高了共混物相界面的粘着力.少量的PP-g-(GMA-co-St)就能使PA6和PC的相容性得到显著改善.当PP-g-(GMA-co-St)的质量分数为10%时,共混物分散相的相区尺寸细化到0.2μm,其力学性能也有较大提高.PA6/PC/PP-g-(GMA-co-St)共混物的力学性能均衡,达到了弹性体增韧体系难以达到的效果.即使PP-g-(GMA-co-St)组分含量为20%时,共混物仍能保持较好的力学性能,特别是在共混物的韧性得以提高的同时,其强度和伸长率也提高.     

Effect of maleic anhydride-grafted ethylene-propylene rubber on the mechanical, rheological and morphological properties of organoclay reinforced polyamide 6/polypropylene nanocomposites

Polyamide 6/polypropylene (PA6/PP = 70/30 parts) blends containing 4 phr (parts per hundred resin) of organophilic modified montmorillonite (organoclay) were compatibilized with maleic anhydride-grafted ethylene-propylene rubber (EPRgMA). The blends were melt compounded in twin screw extruder followed by injection molding. The mechanical properties of PA6/PP nanocomposites were studied by tensile and flexural tests. The microstructure of the nanocomposite were assessed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The dynamic mechanical properties of the PA6/PP blend-based nanocomposites were analyzed by using a dynamic mechanical thermal analyzer (DMTA). The rheological properties were conducted from plate/plate rheometry via dynamic frequency sweep scans. The melt viscosity in a high shear rate region was performed by using a capillary rheometer. The strength and stiffness of the PA6/PP-based nanocomposites were improved significantly with the incorporation of EPRgMA. Adding EPRgMA to the PA6/PP blends resulted in a finer dispersion of the PP phase. TEM and XRD results revealed that the organoclay was dispersed more homogeneously in the presence of EPRgMA, however, mostly in the PA6 phase of the blends. DMTA results showed that EPRgMA worked as an effective compatibilizer. The storage (G′) and loss moduli (G″) assessed by plate/plate rheometry of PA6/PP blends increased with the incorporation of EPRgMA and organoclay. Furthermore, the apparent shear viscosity of the PA6/PP blend increased significantly for the EPRgMA compatibilized PA6/PP/organoclay nanocomposite. This was traced to the formation of an interphase between PA6 and PP (via PA6-g-EPR) and effective intercalation/exfoliation of the organoclay.     

磨盘碾磨制备PA6/PP/SBS共混物的结构与性能

采用磨盘形力化学反应器,在室温下制备了PA6/PP超细混合粉体,与SBS共混制得PA6/PP/SBS共混物,测定了材料的力学性能并用TEM研究了材料在不同加工温度下相结构的变化.结果表明,通过固相力化学粉碎制备的PA6/PP混合微粉,改善了PA6与PP和SBS的相容性,促进了PA6及PP的分散和与SBS的相界面结合.在微粉填充量为4%～8%(质量分数)时,材料的拉伸强度大幅度提高,扯断伸长率保持不变.加工温度变化引起材料相结构的变化对材料性能产生显著影响.在PP熔融温度下加工,PP粒子产生粘连形成链状结构,可提高材料的力学性能.     

显微镜图像分析研究聚丙烯/尼龙1010共混物相结构及其性能

用扫描电子显微镜图像分析研究了聚丙烯/聚酰胺1010共混物及其部分相容体系的相形态结构,计算了表征相结构和尺寸的结构参数,如分散相的平均直径、平均弦长和分散相的质心相关距等.并分别讨论了聚丙烯/聚酰胺1010共混物及其部分相容体系的相形态以及其结构参数与共混物组成的关系.测定了聚合物及其共混物体系的力学性能,讨论了共混物组成与力学性能的关系.聚丙烯/聚酰胺1010共混物的拉伸模量与组成的关系较为复杂,但其部分相容体系的拉伸模量与组成呈线性关系.聚丙烯/聚酰胺1010及其共混物体系的屈服强度与共混物组成均呈线性关系.表征相结构的两相平均弦长比(l-1/-l2)与组成以及共混物体系力学性能与组成的关系,二者相似.同时讨论了体系力学性能随相尺寸等的变化规律.     

Effect of the microstructure on the dye diffusion and mechanical properties of polyamide‐6 fibers

The morphology, mechanical properties, and dye diffusion of drawn and heat‐set polyamide‐6 (PA6) yarns were examined. Correlations between the microstructure of PA6 yarns and the dye diffusion coefficients and mechanical properties were established. The crystallinity of PA6 yarns was estimated with density and Fourier transform infrared spectroscopy measurements. A decrease in the γ crystallinity and an increase in the γ‐crystallite size with the draw ratio were observed and attributed to the disappearance of small crystallites and an increase in the average γ‐crystallite size population during the deformation process. The scouring treatment increased the total crystallinity, almost entirely as a result of an increase in the α fraction. Thermally induced crystallization involved increases in both crystalline phases (α and γ) and did not involve crystal‐to‐crystal transformation, whereas drawing PA6 yarns involved both crystallization of the amorphous phase in the α form and γ→α transformation. A sharp decrease in the diffusion coefficient with an increasing draw ratio of PA6 yarns was correlated with an increasing amorphous orientation. The influence of thermally induced crystallinity on the diffusion coefficient seemed exceptionally strong. The mechanical properties of PA6 yarns were examined and correlated with structural changes. It was demonstrated that the crystallinity had a direct correlation with the terminal modulus and extension at break, whereas there was no correlation with the initial modulus. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 349–357, 2007     

PA6/HIPS/PP-g-(GMA-co-St)反应共混体系的研究

通过扫描电镜、热分析、熔体流动速率、熔融扭矩和力学性能等测试方法研究了甲基丙烯酸缩水甘油酯(GMA)和苯乙烯(St)多单体熔融接枝聚丙烯[PP-g-(GMA-co-St)]对PA6/HIPS共混物的熔融流变性能、结晶行为、相形态和力学性能的影响.结果表明,在熔融共混过程中,PP-g-(GMA-co-St)中的环氧基与PA6的端氨基原位生成的接枝共聚物有效地降低了共混物的界面张力,提高了共混物的界面粘着力,使共聚物的流动速率降低,熔融扭矩提高;PA6分子链的规整性降低,结晶完善性变差.在PP-g-(GMA-co-St)的质量分数为10%时,共混物分散相的尺寸明显减少,力学性能得到较大提高;其中冲击强度超过纯PA6,达到HIPS水平.通过反应共混,制备了力学性能均衡的PA6/HIPS/PP-g-(GMA-co-St)共混物合金.