Microwave Characteristics of Polyaniline Based Short Fiber Reinforced Chloroprene Rubber Composites

This report presents the microwave characteristics of conducting polymer composites (CPCs) based on chloroprene rubber with special reference to dielectric properties. CPCs based on polyaniline (PANI), polyaniline-coated short nylon fiber (PANI-N) and chloroprene rubber (CR) were prepared by mechanical mixing. The important properties like dielectric permittivity, loss tangent, conductivity, and dielectric heating coefficient were evaluated and compared. It was found that PANI/CR composites had very good dielectric properties in the microwave range. The addition of PANI-N improved the mechanical properties of the composites with reasonably good dielectric properties. The CPCs were also found to have good microwave absorption.     

改性锦纶66短纤维/天然橡胶复合材料性能研究

对锦纶66（PA66）短纤维进行紫外光照射和浸渍液体橡胶物理改性,以及接枝化学改性共同处理,制备改性PA66短纤维/天然橡胶（NR）复合材料,并研究PA66短纤维改性方式对复合材料性能的影响。结果表明：与未改性的PA66短纤维/NR复合材料相比,改性PA66短纤维/NR复合材料的拉伸强度降低、撕裂强度提高;其中先接枝再紫外光照的PA66短纤维/NR复合材料的100%定伸应力变化不大,300%定伸应力提高,拉断伸长率变化不大;先紫外光照再接枝的PA66短纤维/NR复合材料的100%定伸应力和300%定伸应力明显提高,拉断伸长率明显降低。综合来看,经紫外光照4 min＋接枝乙烯基三甲氧基硅烷＋浸渍2 g液体橡胶处理的改性PA66短纤维/NR胶料的物理性能、粘合性能和尺寸稳定性最好。     

Synthesis and Characterization of Conducting Composites of Polypyrrole/Polypyrrole-Coated Short Nylon Fiber and Natural Rubber

Pyrrole was polymerized in the presence of anhydrous ferric chloride as oxidant and p-toluene sulphonic acid as dopant. Polypyrrole-coated short Nylon fibers were prepared by polymerizing pyrrole in the presence of short Nylon fibers. The resultant polypyrrole (PPy) and polypyrrole-coated Nylon fiber (F-PPy) were characterized using SEM and then used to prepare rubber composites based on natural rubber. The cure pattern, cure kinetics, filler dispersion, DC conductivity, mechanical properties and morphology of the resulting composites were studied. The presence of PPy-coated fibers in the natural rubber/PPy system reduced the cure time significantly. The DC conductivity of the composites was found to be better for the F-PPy system compared to PPy-filled NR composite. The F-PPy system also showed better tensile strength, modulus and tear resistance.     

锦纶短纤维/天然橡胶复合材料的性能研究

制备锦纶66短纤维/天然橡胶(NR)复合材料,并研究锦纶短纤维用量对复合材料性能的影响。结果表明:锦纶短纤维可以提高胶料的定伸应力和撕裂强度,当锦纶短纤维用量为4份时,锦纶短纤维/NR复合材料的综合物理性能最好;添加锦纶短纤维增大了填料有效体积,提高了对橡胶分子链的束缚,使橡胶分子在剪切作用力下运动受阻,提高了抵抗外力变形的能力;锦纶短纤维降低了NR胶料的玻璃化转变温度,有利于NR胶料在低温下使用。     

Cure Characteristics and Mechanical Properties of HRH Bonded Nylon-6 Short Fiber-Nanosilica-Acrylonitrile Butadiene Rubber Hybrid Composite

Nano silica was synthesized by acid hydrolysis of sodium silicate using diluted hydrochloric acid. This synthetic nanosilica was used in place of hydrated silica in a HRH (hexamethylenetetramine, resorcinol and silica) bonding system for acrylonitrile butadiene rubber–nylon-6 short fiber composite. Nanosilica was also used as a reinforcing filler in acrylonitrile butadiene rubber–nylon-6 short fiber hybrid composite. Cure characteristic and mechanical properties of the hybrid composites were evaluated. Minimum torque, maximum torque, and cure time of the hybrid composites increased with silica loading. Cure rate increased with fiber loading and decreased with silica content. Scorch time also decreased with fiber loading and silica content. Volume fraction of rubber in a solvent-swollen sample increased with nanosilica. The efficiency of the HRH dry bonding system was improved in the presence of nanosilica. Nanosilica in the rubber composites also improved the tensile strength, modulus, and tear strength better than the conventional silica composites. Abrasion loss, hardness, resilience, and compression set properties were also better for the nano silica composites. The composites showed anisotropy in mechanical properties.     

短切碳纤维增强尼龙66复合材料研究进展

碳纤维的表面处理和尼龙的改性以及各种碳纤维/尼龙基复合材料的制备是当前研究热点之一。与纯尼龙相比,碳纤维的加入使材料表现出更优异的力学和摩擦学性能,拓展了尼龙高技术领域的应用空间。概述了碳纤维/尼龙66复合材料的制备方法、结构及性能方面研究进展,并提出了相关研究方向,为今后提高碳纤维增强尼龙66基复合材料力学性能和摩擦学性能研究提供参考。     

改性石墨烯对天然橡胶/丁腈橡胶复合材料热性能的影响

采用超声辅助超临界CO2方法制备石墨烯,经3-氨丙基三乙氧基硅烷(APTES)改性后,采用"预混合"的方法,得到硬脂酸/石墨烯母料。通过机械共混法制备天然橡胶(NR)/改性石墨烯(GNs)与丁腈橡胶(NBR)/GNs复合材料。通过分析复合材料的导热性能、热管理性能和压缩生热性能的变化情况,验证石墨烯的性能与硬脂酸/石墨烯"预混合"对石墨烯分散的影响。结果表明,添加3份GNs时,NRC-3、NBRC-3的导热性能分别提升了108%和194%,压缩温升降低了8. 9℃和9. 9℃。该方法制备的石墨烯导热性能优秀,硬脂酸/石墨烯的"预混合"有效改善了石墨烯在聚合物中的分散性。     

白炭黑/炭黑复合填充对NR性能的影响

在白炭黑和炭黑填料总量一定的情况下,研究了不同白炭黑/炭黑配比对NR性能的影响。结果表明,白炭黑用量增加,NR硫化速率下降,体系中炭黑填料网络被破坏且白炭黑-橡胶间较弱的相互作用也会对NR硫化胶力学性能产生一系列影响。DMA结果表明,加入20~25份白炭黑对提高硫化胶的抗湿滑性和降低滚动阻力最为有效。     

短尼龙弹力丝增强橡胶性能研究

对采用短尼龙弹力丝制得的短纤维橡胶复合材料与采用普通尼龙短纤维的复合材料进行了加工性能和物理性能的对比。结果表明,短尼龙弹力丝更容易在胶料中分散均匀,其与橡胶的复合材料具有优异的物理性能。     

芳纶短纤维增强天然橡胶复合材料性能研究

研究添加不同用量的芳纶短纤维/天然橡胶(NR)复合材料的性能。结果表明,NR复合材料的性能随着芳纶短纤维用量的增大先提高再下降;添加2份芳纶短纤维时复合材料的物理性能较好,磨耗性能也较优;添加芳纶短纤维能够使复合材料的抗湿滑性能变好,滚动阻力增大,导热性降低。     

改性石墨烯/天然橡胶复合材料的制备及性能研究

本研究采用γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)对石墨烯(GE)进行改采用γ-甲基丙烯酰氧基丙基三甲氧基硅烷（KH-570）对石墨烯（GE）进行改性,将得到的改性石墨烯（KH-GE）与天然橡胶（NR）进行混炼制备改性石墨烯/天然橡胶（KH-GE/NR）复合材料。采用傅里叶红外光谱仪、拉曼光谱仪、X射线衍射仪和场发射扫描电镜对改性前后石墨烯结构进行表征,同时研究了KH-GE/NR复合材料的硫化性能、力学性能和导电性能。结果表明：硅烷偶联剂KH-570对GE改性后,增大了GE的层间距,改善了GE在NR基体中的分散;随着KH-GE用量增加,KH-GE/NR复合材料力学性能提高,当KH-GE质量分数为1.0 %时,KH-GE/NR复合材料的拉伸强度和断裂伸长率分别为17.57Mpa和645.48%,比未添加KH-GE的复合材料分别提高122%和21%,同时复合材料的体积电阻率最终下降约三个数量级。     

Novel HTPB/MWNTs-COOH PU Conductive Polymer Composite Films for Detection of Hazardous Organic Solvent Vapors

A novel polyurethane (PU) conducting composite film was developed by a simple coupling reaction route. The morphologies and structural characterization were conducted by means of FTIR, UV-vis, XRD, TEM, TGA and POM. The influence of the MWNTs-COOH loading amount and curing temperature on response was investigated. The results indicated that the films displayed strong and selective response to some non-polar organic solvent vapor, and have long-term stability. The film loading 15.5 wt% conductive filler exhibited higher response. As the curing temperature is increased, the response is increased, demonstrating the potential for developing a new class of stable and sensitive sensors.     

Effect of the Electroplating Process Waste upon Vulcanization and Mechanical Properties of Natural Rubber (NR) Compositions

The potential of EWPS (electroplating waste of the polishing step) as activator for vulcanization process has been evaluated. EWPS was incorporated into natural rubber (NR) formulation in replacement partial or total to ZnO. The different mixtures were obtained in a laboratory-size two-roll mill and conventional vulcanization system (CV) was chosen for vulcanization. Rheometer parameters (t_s1, t₉₀, and M_h), mechanical properties (tensile and tear strength) and cure studies at 150, 160 and 170°C for a kinetic model were carried out. EWPS shows some catalytic effect upon NR vulcanization with reduction of scorch and optimum cure time. However, the compounds where EWPS is present in major quantity, in relation to ZnO, or alone as activator present a depleted performance with a continuous reduction of properties, such as, tensile strength.     

废尼龙短纤维/丙烯酸酯橡胶复合材料的性能研究

对废尼龙短纤维／丙烯酸酯橡胶复合材料中短纤维的分布状态和复合材料的性能进行了研究。结果表明,废尼龙短纤维能较好地分散在丙烯酸酯橡胶中;随短纤维用量的增大,复合材料的定伸应力和撕裂强度增大,抗溶胀性能提高,但拉伸强度减小     

Tensile and Impact Properties of Thermoplastic Natural Rubber Reinforced Short Glass Fiber and Empty Fruit Bunch Hybrid Composites

Thermoplastic natural rubber (TPNR) hybrid composite with short glass fiber (GF) and empty fruit bunch (EFB) fiber were prepared via the melt blending method using an internal mixer type Thermo Haake 600p. The TPNR were prepared from natural rubber (NR), liquid natural rubber (LNR) and polypropylene (PP) thermoplastic, with a ratio of 20:10:70. The hybrid composites were prepared at various ratios of GF/EFB with 20% volume fraction. Premixture was performed before the material was discharged into the machine. The study also focused on the effect of fiber (glass and EFB) treatment using silane and maleic anhydride grafted polypropylene (MAgPP) as a coupling agent. In general, composite that contains 10% EFB/10% glass fiber gave an optimum tensile and impact strength for treated and untreated hybrid composites. Tensile properties increase with addition of a coupling agent because of the existence of adherence as shown in the scanning electron microscopy (SEM) micrograph. Further addition of EFB exceeding 10% reduced the Young's modulus and impact strength. However, the hardness increases with the addition of EFB fiber for the untreated composite and decreases for the treated composite.     

Porous and self-strengthened poly(ε-caprolactone)/calcium sulfate hemihydrate composite fibers for bone regeneration

Porous polycaprolactone (PCL)/calcium sulfate hemihydrate (CSH) composite fibers with different compositions were fabricated via electrospinning by using chloroform/dimethyl sulfoxide (volume ratio = 8:2) as the co-solvent. It was found that the incorporation of fine CSH powders greatly improved the morphology of the PCL fibers and generated continuous, bead-free PCL/CSH composite fibers with the pore diameter varying from 0.2 to 1.1 μm when 20% CSH was added. As compared with the PCL fibers, the PCL/CSH composite fibers also exhibited enhanced thermal stability and hydrophilicity. The tensile strength and elastic modulus of the PCL/CSH fibrous membranes first increased and then decreased with the increase of the CSH content, while their ductility exhibited a sustained decrease. Moreover, after immersion in water, the PCL-20%CSH composite fibers presented a much higher tensile strength than the pristine ones probably due to the self-setting of the CSH powders through the porous structure. In addition, the PCL-20%CSH composite fibers displayed a strong ability to form bone-like apatite after immersion in simulated body fluid for 3 days, which suggests their potential applications in bone tissue regeneration as a novel type of substitute.     

Cure Characteristics and Mechanical Properties of Short Nylon-6 Fiber Neoprene Rubber Composite Containing Epoxy Resin as Bonding Agent

ABSTRACT

Cure characteristics and mechanical properties of the short nylon fiber reinforced neoprene rubber with and without epoxy bonding agent at various fiber loadings were studied. The fiber loading was varied from 0 to 30 phr and the resin content was in the range 0 to 5 phr. Minimum torque and cure time were increased in the presence of resin. Mechanical properties like tensile strength and abrasion resistance showed an increase with resin concentration. It was found that epoxy based bonding agents enhanced the properties of short nylon fiber reinforced neoprene rubber.     

The Mechanical and Physical Properties of Thermoplastic Natural Rubber Hybrid Composites Reinforced with Hibiscus cannabinus,L and Short Glass Fiber

Thermoplastic natural rubber hybrid composites reinforced with kenaf and short glass fibers were compounded by melt blending method using an internal mixer, Thermo Haake 600P. Thermoplastic natural rubbers (TPNR) were prepared from polypropylene (PP), natural rubber (NR) and liquid natural rubber (TPNR) with ratio 70:20:10, which were blended using internal mixer for 12 minutes at 180°C and rotor speed 40 r.p.m. Glass fiber was treated with silane coupling agent while TPNR reinforced kenaf fiber composite is using MAPP as a compatibilizer. TPNR hybrid composite with kenaf/glass fibers was prepared with fiber content (5, 10, 15, 20 volume % of fiber). Mechanical properties of the composites were investigated using tensile test^{[ 1} Anuar , H. ; Ahmad , S.H. ; Rasid , R. ; Wan Busu , W.N. Reinforced thermoplastic natural rubber hybrid composites with Hibiscus cannabinus, L and short glass fiber – Part I: Processing parameters and tensile properties . J. Compos. Mater. 2008 , 42 , 1075 – 1087 . [Google Scholar] ^], flexural, impact, and hardness test and scanning electron microscope (SEM)^{[ 1} Anuar , H. ; Ahmad , S.H. ; Rasid , R. ; Wan Busu , W.N. Reinforced thermoplastic natural rubber hybrid composites with Hibiscus cannabinus, L and short glass fiber – Part I: Processing parameters and tensile properties . J. Compos. Mater. 2008 , 42 , 1075 – 1087 . [Google Scholar] ^]. The incorporation of the treated or untreated fiber into TPNR has result in an increment of almost 100% of flexural modulus and impact strength as compared to TPNR matrix. However, the maximum strain decreased with increasing fiber content. The optimum composition for hybrid composite is at the fiber ratio of 30% kenaf fiber and 70% glass fiber. The SEM micrograph had shown, that the composite with coupling agent or compatibilizer promote better fiber-matrix interaction.     

MC尼龙6/纳米TiO2原位复合材料性能研究

通过阴离子原位聚合法制备了MC尼龙6／纳米TiO2复合材料,采用透射电子显微镜观察了纳米TiO2在复合材料中的分散形态,并研究了纳米TiO2含量对复合材料的热稳定性和力学性能的影响。结果表明：在纳米TiO2质量分数低于2％时,纳米TiO2能较均匀地分散在复合材料中,对复合材料同时具有增强和增韧的作用;纳米TiO2的加入提高了复合材料热稳定性,使MC尼龙6的起始降解温度提高2～3℃,最大失重速率温度大幅度提高,并随纳米TiO2用量的增加而升高。     

玄武岩短纤维/硅橡胶复合材料性能研究

采用玄武岩短纤维补强硅橡胶,研究玄武岩短纤维/硅橡胶复合材料的性能。结果表明:用丙酮脱玄武岩短纤维表面的浆膜,处理时间为50 min时效果最佳;用偶联剂KH-550对玄武岩短纤维表面进行处理,且玄武岩短纤维用量为20份时,玄武岩短纤维/硅橡胶复合材料的综合性能最佳;制备玄武岩短纤维/硅橡胶复合材料的最佳硫化条件为175℃/10 MPa×25 min。