新型炭黑填充抗静电和导电聚丙烯复合材料

以炭黑为导电填料,在聚丙烯中加入适量的环氧树脂和玻璃纤维,制备了新型的抗静电和导电聚丙烯复合材料。测定了不同复合体系的渗滤阈值,用扫描电镜(SEM)对相形貌进行了观察,并研究了环氧树脂和玻璃纤维用量对体积电阻率的影响。SEM照片表明在新型复合材料中,炭黑优先分布在环氧树脂中,环氧树脂包覆在玻璃纤维表面,通过玻璃纤维间的搭接形成导电通路。这种独特的结构使该复合材料的渗滤阈值低于聚丙烯/炭黑和聚丙烯/环氧树脂/炭黑复合体系的渗滤阈值。玻璃纤维和环氧树脂含量分别需要达到约10%,复合材料才能具有抗静电和导电作用。     

PP/POE/CB半导电屏蔽复合材料的制备和性能

研究了导电炭黑含量和聚乙烯-辛烯弹性体接枝马来酸酐(POE-g-MAH)的加入对热塑性半导电屏蔽材料,即聚丙烯烯/聚乙烯-辛烯弹性体/炭黑(PP/POE/CB)复合体系的体积电阻率和力学性能的影响,并通过扫描电镜(SEM)分析了POE-g-MAH的加入对PP基热塑性半导电屏蔽复合材料断面形貌的影响。利用转矩流变仪对复合材料的流变性能进行了研究。结果表明,PP/POE/CB热塑性半导电屏蔽复合材料的逾渗现象与炭黑粒子在聚合物基体中的分布状态有关,POE-g-MAH的加入可以进一步降低复合材料的体积电阻率;随着导电炭黑含量的增加,复合材料的拉伸强度均呈现先增加,后降低的趋势,当炭黑用量为30%时,拉伸强度达到最大值。PP/POE/CB热塑性半导电屏蔽复合材料具有较高的导电性能、力学性能、较高的熔体流动速率及良好的加工流动性。     

过氧化物母粒对PP/炭黑导电复合材料的影响

采用含有过氧化物的聚丙烯(PP)母粒,通过熔融共混法制备了不同熔体流动速率(MFR)的PP/炭黑导电复合材料,并研究了复合材料的流变性能、结晶性能、力学性能及导电性能。结果表明:PP过氧化物母粒的加入有效改善了PP/炭黑导电复合材料的流动性。PP过氧化物母粒质量分数为2.2%时,复合材料的结晶度是25.96%,拉伸强度、冲击强度分别达到25.96 MPa、73.70 kJ/m~2。PP过氧化物母粒的加入对复合材料导电性能的影响较小。     

聚丙烯/炭黑/废纸纤维导电复合材料的性能研究

通过熔融共混方式制备了聚丙烯/炭黑/废纸纤维导电复合材料，研究废纸纤维含量和炭黑含量对复合材料体积电阻率、力学性能、流变性能和热稳定性能的影响，并通过扫描电镜分析了废纸纤维及炭黑在复合材料基体中的分散情况。结果表明：废纸纤维的加入有效降低复合材料的体积电阻率。当炭黑含量为12%时，随着废纸纤维含量由0增至10%，复合材料体积电阻率由2.41×1014Ω·cm降至9.3×108Ω·cm。废纸纤维能够有效提高复合材料的力学性能，当炭黑含量为12%、废纸含量为10%时，复合材料的拉伸模量、弯曲模量、冲击强度相比于未添加废纸时分别提高24%、35%和11.7%。废纸纤维的加入增加复合材料的平衡转矩，降低熔体流动速率，含量较高时影响作用明显。废纸纤维的加入降低聚丙烯/炭黑复合材料的热稳定性。     

炭黑/废纸导电纤维的制备及其在聚丙烯中的应用

利用多巴胺氧化自聚合将炭黑粘附到废纸纤维表面,制备了炭黑/废纸柔性导电纤维,分析了炭黑含量对纤维导电性能的影响,然后,将该导电纤维与聚丙烯熔融共混制备复合材料,分析了导电纤维添加量对复合材料导电和力学性能的影响。结果表明,聚多巴胺将炭黑均匀粘附在废纸纤维表面,纤维的电阻率随着炭黑含量增加而逐渐降低,当炭黑含量为15%时,废纸纤维的电阻率log ρ下降至2.16Ω·cm。柔性导电纤维能更好地控制聚丙烯复合材料电导率降低幅度,当纤维添加量为15%(炭黑含量为2.27%)时,复合材料的表面电阻率为3.71×10¹⁰Ω,体积电阻率为2.45×10¹¹Ω·cm,能达到抗静电级别。此时,复合材料的弹性模量和拉伸强度分别为565.65和17.01 MPa,模量提高了1.07%,但强度降低了32.82%。     

可导电玻璃纤维增强聚丙烯材料的性能分析

研究了导电炭黑(CB)的不同添加方式、不同导电炭黑母粒含量对玻璃纤维增强聚丙烯材料的表面电阻率、力学性能和熔体流动速率的影响.结果表明,导电炭黑母粒对聚丙烯材料的分解温度没有影响;导电通路的形成与导电炭黑在玻璃纤维增强聚丙烯体系中的分散性有关;添加导电炭黑母粒体系中更有利于形成导电通路;当导电炭黑母粒添加至40％时,玻...     

导电炭黑对木粉/PP复合材料抗静电及力学性能的影响

文章对比分析了非离子型抗静电剂、高分子型抗静电剂与导电炭黑对木粉/PP复合材料的抗静电作用,重点探讨了导电炭黑的添加量对其抗静电及力学性能的影响。结果表明:与非离子型抗静电剂、高分子型抗静电剂相比,导电炭黑对木粉/PP复合材料的抗静电作用效果更优;当导电炭黑的添加量达到8份时,复合材料的表面电阻率和体积电阻率分别达到1.64×10~8?和2.54×10~8?·cm,具有较好的抗静电效果;在马来酸酐接枝聚丙烯(MAPP)的存在下,导电炭黑提高了木粉/PP复合材料的抗弯性能。     

不同填充物改性聚丙烯复合材料的研究

研究了滑石粉、玻璃纤维、碳酸钙三种不同的填充物与聚丙烯共混改性对复合材料力学性能、收缩率、阻燃性能的影响。结果表明,玻璃纤维填充对提高复合材料力学性能和降低复合材料收缩率的作用最大,但在提高复合材料阻燃性方面不如滑石粉,碳酸钙对复合材料力学性能的增强、降低收缩率和提高阻燃性的作用都不如玻璃纤维和滑石粉。     

炭黑填充聚丁烯复合材料导电性能的探讨

研究了炭黑/聚丁烯复合材料的导电性能。结果表明:同炭黑/聚乙烯、炭黑/聚丙烯复合材料类似,炭黑/聚丁烯复合材料具有明显的渗滤效应,不同炭黑的渗滤阀值相差较大。影响复合材料导电性能的因素有:炭黑添加量、炭黑表面化学性质、炭黑结构。     

导电炭黑对玻璃纤维增强环氧树脂复合材料电性能的影响

以导电炭黑填充玻璃纤维增强环氧树脂复合材料,通过测定复合材料的静电屏蔽电压、静电衰减时间、表面电阻率数值,对影响电性能的几个主要因素进行了研究。结果表明,导电炭黑填充复合材料的防静电效果显著,导电炭黑适宜用量为1.1~1.2份,粒度为7~9 nm;填充时,将导电炭黑直接加入到环氧树脂体系中,然后用高速分散机搅拌10~15 min。     

Electrical properties and morphology of polypropylene/epoxy/glass fiber composites filled with carbon black

The volume resistivity and percolation thresholds of carbon black (CB) filled polypropylene (PP), PP/epoxy, and PP/epoxy/glass fiber (GF) composites were measured. The morphology of these conductive polymer composites was studied with scanning electron microscopy (SEM). The effects of the GF and epoxy contents on the volume resistivity were also investigated. The PP/epoxy/GF/CB composite exhibited a reduced percolation threshold, in comparison with that of the PP/CB and PP/epoxy/CB composites. At a given CB content, the PP/epoxy/GF/CB composite had a lower volume resistivity than the PP/CB and PP/epoxy/CB composites. SEM micrographs showed that CB aggregates formed chainlike structures and dispersed homogeneously within the PP matrix. The addition of the epoxy resin to PP resulted in the preferential location of CB in epoxy, whereas in the PP/epoxy/GF multiphase blends, because of the good affinity of CB to epoxy and of epoxy to GF, CB particles were located in the epoxy phase coated on GF. The decreased percolation threshold and volume resistivity indicated that conductive paths existed in the PP/epoxy/GF/CB composite. The conductive paths were probably formed through the interconnection of GF. Appropriate amounts of GF and epoxy should be used to decrease the volume resistivity and provide sufficient epoxy coating. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1142–1149, 2005     

聚丙烯/尼龙/玻璃纤维/炭黑四元双逾渗复合体系的压阻行为

研究了聚丙烯（PP）/尼龙（PA）/玻璃纤维（GF）/炭黑（CB）四元复合体系的逾渗现象与压阻行为。通过SEM分析得出PA/CB体系的逾渗作用及其包裹GF对PP逾渗作用形成的导电网络是四元体系导电的根源,而且电阻的变化与GF的含量密切相关。GF低含量下出现微弱的NPC现象,在高含量下随应力的增大先出现的NPC现象,后出现PPC现象,本文对两种现象出现的原因进行了理论阐述。经多次应力循环,体系电阻的稳定性得到很大改善。     

Crystallization behavior of carbon black‐filled polypropylene and polypropylene/epoxy composites

The crystallization behavior of polypropylene (PP)/carbon black (CB) and PP/epoxy/CB composites was studied with differential scanning calorimetry (DSC). The effects of compatibilizer MAH‐g‐PP and dynamic cure on the crystallization behavior are investigated. The nonisothermal crystallization parameters analysis showed that CB particles in the PP/CB composites and the dispersed epoxy particles in the PP/epoxy composites could act as nucleating agents, accelerating the crystallization of the composites. Morphological studies indicated that the incorporation of CB into PP/epoxy resulted in its preferential localization in the epoxy resin phase, changing the spherical epoxy particles into elongated structure, and thus reduced the nucleation effect of epoxy particles. Addition of MAH‐g‐PP significantly decreased the average diameter of epoxy particles in the PP/epoxy and PP/epoxy/CB composites, promoting the crystallization of PP more effectively. The isothermal crystallization kinetics and thermodynamics of the PP/CB and PP/epoxy/CB composites were studied with the Avrami equation and Hoffman theory, respectively. The Avrami exponent and the crystallization rate of the PP/CB composites were higher than those of PP, and the free energy of chain folding for PP crystallization decreased with increasing CB content. Addition of MAH‐g‐PP into the PP/epoxy and PP/epoxy/CB composites increased the crystallization rate of the composites and decreased the chain folding energy significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 104–118, 2006     

Preparation of polypropylene/glass fiber composite with high performance through interfacial crystallization

This paper reported an approach to improve the interaction between glass fiber (GF) and polypropylene (PP) through interfacial crystallization. The experimental results showed that polar nucleating agents had strong interaction with GF and tended to deposit on the surface of GF through the dip‐coating method. Since the nucleating agents had good lattice matching with PP, the modified GF could promote the interfacial crystallization of PP to increase the interfacial interaction between GF and PP and improve the performance of PP/GF composites. However, at high processing temperature, the nucleating agents dissolved into the polymer melts, and the nucleation on the GF surface for PP crystallization decreased, impairing the interface compatibility and the final performance of the PP/GF composites. J. VINYL ADDIT. TECHNOL., 23:284–289, 2017. © 2015 Society of Plastics Engineers     

Study on the crystallization kinetics of PP/GF composites

The crystallization kinetics and morphology of glass fiber-reinforced polypropylene (PP/GF) were investigated in this work. Both isothermal and nonisothermal crystallization behaviors of 90PP/10GF, 80PP/20GF, and 70PP/30GF were examined with a DSC instrument. It was found that the addition of glass fiber would increase the crystallization rate of PP and increase the content of β spherulite, which was most likely formed at temperatures between 390 and 400 K. The morphology of spherulites of PP/GF composites were examined with SEM and a polarized microscope. All experimental observations conformed rather well with the theoretical approach, a dynamic crystallization model, proposed in our previous work. The size of α spherulites of PP would decrease at lower crystallization temperature, or at higher cooling rate, or by adding glass fiber in it.     

玻璃纤维增强木质素/PP复合材料结构和性能的研究

采用熔融共混和模压成型方法,制备了玻璃纤维(GF)增强木质素/聚丙烯(PP)复合材料,研究复合材料力学性能、热性能、晶型结构和微观结构。结果表明:当GF加入质量分数为30%时,复合材料的冲击强度、弯曲强度和弯曲模量较未加GF的分别提高了1.21,1.74和0.79倍;热稳定性、结晶性和结晶速率也有明显的提高。利用扫描电镜观察其断裂形貌,探讨其增韧机理。     

Structure and properties of PP/SBS/glass fiber hybrid composites. Part I: Crystallization behavior and morphology

The structure development, crystallization behavior and morphology were studied in hybrid composites made with polypropylene/styrene‐butadiene‐styrene (PP/SBS) containing glass fibers (GF). The techniques applied include optical polarizing microscopy, X‐ray diffraction and scanning electron microscopy (SEM). The isothermal crystallization studies of PP/SBS/GF revealed that SBS as well as GF could act as good nucleating agents for PP. However, the nucleation efficiency of GF is much higher than that of the SBS. At high concentrations of SBS (> 30%), the crystallization rate decreases even in the presence of GF. This was attributed to the strong bonding between SBS and glass, giving rise to an intermediate layer of SBS between PP and GF, which was confirmed from the SEM of the fractured morphology of the injection molded hybrid composite. The orientation of GF was observer in the injection molded samples for certain compositions, and this was accompanied by an increase of intensities of particular diffraction peaks in the XRD.     

Microstructure and properties of polypropylene/glass fiber composites grafted with poly(pentaerythritol triacrylate)

Isotactic polypropylene(PP)/glass fiber(GF) composites were modified by grafting polymerization of polyfunctional monomer, pentaerythritol triacrylate (PETA), in the presence of 2,5-dimethyl-2,5-di(tert-butylperoxy) hexane peroxide (DDHP) via melt extrusion. Fourier transform infrared spectroscopy (FTIR), melt strength test (MS), mechanical property test, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to characterize the microstructure and properties of the modified composites. The crystallization kinetics was investigated by Mo method while apparent activation energy of crystallization of the composites was determined by Kissinger method. The FTIR results showed that the acrylic polymers were grafted onto the polypropylene chains. The grafting made the melt strengths and the mechanical properties of the modified composites, and the interfacial adhesion between PP and glass fiber all enhanced. High melting and crystallization temperatures, high crystallization rate and large activation energy of crystallization were also obtained after grafting. In addition, the grafted acrylic polymers recovered the depressed crystallization of polypropylene and restrained α-β transition in fatigue experiment.     

PP/纳米SiO2复合材料的非等温结晶动力学

采用差示扫描量热法研究了聚丙烯（PP）/纳米SiO2复合材料的非等温结晶动力学,研究了纳米粒子的成核活性及复合材料的结晶有效能垒。研究结果表明,纳米SiO2起到异相成核的作用,使PP的结晶峰温升高,结晶总速率增大;增容剂马来酸酐接枝聚丙烯(PP-g-MAH)提高了纳米SiO2的成核活性;添加纳米SiO2使复合材料的结晶有效能垒降低,PP-g-MAH使复合材料的结晶有效能垒增大,但低于纯PP的结晶有效能垒。     

PP/PP-g-NH2/纳米SiO2复合材料的非等温结晶

采用示差扫描量热法（DSC）研究了聚丙烯/氨基化聚丙烯/纳米二氧化硅（PP/PP-g-NH₂/SiO₂）复合材料的非等温结晶行为。利用Caze法对结晶动力学进行了分析,Avrami指数n表明纳米SiO₂和PP-g-NH₂的加入改变了PP的结晶成核和生长机理;运用Dobreva法研究了纳米粒子的成核活性,结果表明纳米SiO₂成核活性差,增容剂PP-g-NH₂明显增强其成核活性;采用Friedman法分析了复合材料的结晶有效能垒,研究表明加入纳米SiO₂使PP的结晶有效能垒降低,添加PP-g-NH₂则进一步降低复合体系的结晶有效能垒;当纳米粒子含量为3%时,添加5% PP-g-NH₂能有效提高纳米粒子成核活性,降低复合材料结晶有效能垒。