超细二氧化硅纤维/橡胶复合材料的结构和性能研究

通过静电纺丝技术制备超细二氧化硅纤维,研究其对胎面胶物理性能和动态力学性能的影响。结果表明:二氧化硅纤维具有较大的长径比,在胎面胶中的分散性较好,可提高橡胶复合材料的100%定伸应力;当纤维取向方向与外力方向一致时,复合材料60~80℃下的损耗因子(tanδ)最小;当纤维取向与外力方向垂直时,复合材料-20~0℃下的tanδ较大。     

芳纶浆粕纤维在NR/BR胎面胶中的应用研究

研究新型芳纶浆粕(超细)纤维对NR/BR胎面胶的补强性能.结果表明,芳纶浆粕纤维补强的NR/BR硫化胶具有良好的模量-滞后平衡效应,加入3份芳纶浆粕纤维能将硫化胶20%应变的拉伸模量提高近2倍,0 ℃时的损耗因子增大而60 ℃时的损耗因子略有减小,对胶料的加工性能几乎没有影响.低用量芳纶浆粕纤维补强的NR/BR并用胶较适用于轮胎胎面胶.     

不同碳纤维取向角对高尔夫球杆材料阻尼性能的研究

基于T700碳纤维及本试验自制的双组分聚氨酯树脂制备了碳纤维取向角不同的7组薄板,并对其动、静态热力学性能进行了详细研究,结果表明:0.42%/s和0.55%分别为材料形变速度和形变量的临界值,即当形变速度或形变量大于它们时,损耗因子会随之变大而变大;当小于它们时,损耗因子基本上不受其影响。碳纤维取向角越大,损耗因子越大,材料的阻尼性能越差。此外,为了验证上述结论的有效性,将实验数据与理论模型计算得出的数据进行对比,证明了结论的可靠性。     

PAN分子取向程度与纤维结构性能的关系

研究了丙烯腈(AN),甲叉丁二酸(ITA)聚合体系中PAN分子取向与纤维结构、性能之间的关系。 结果表明:在一定范围内,PAN分子取向因子的增加有利于提高纤维的结晶度和(100)晶面法线方向上晶粒 尺寸,提高纤维的体积密度和力学性能。但同时增加了纤维内应力,使纤维的沸水收缩率增加。综合考虑取 向因子对纤维结构性能因素的影响,认为PAN原丝晶区取向因子约为0.9、总取向因子约为0.8时,纤维力 学性能较好。     

短钢丝纤维复合车辆轮胎胎面的性能影响及强化机理研究

以短钢丝纤维作为补强体,通过短钢丝纤维表面镀铜-镀锌处理,设计了短钢丝纤维补强轮胎胎面的配方体系、共混及制备工艺。试验结果表明,当5 mm短钢丝纤维的质量分数在0.10左右时,其补强效果较为理想。构建了短钢丝纤维4种分散情况下的胎面胶复合强化模型,并在此基础上分析了短钢丝纤维与胎面胶的复合强化机理,有效实现了短钢丝纤维与胎面胶的粘合,复合体综合性能表现良好.     

短钢丝纤维对轮胎胎面性能的影响及强化机理研究

以短钢丝纤维作为补强体,通过短钢丝纤维表面镀铜-镀锌处理,设计了短钢丝纤维补强轮胎胎面的配方体系、共混及制备工艺。试验结果表明,当5 mm短钢丝纤维的质量分数在0.10左右时,其补强效果较为理想。构建了短钢丝纤维4种分散情况下的胎面胶复合强化模型,并在此基础上分析了短钢丝纤维与胎面胶的复合强化机理,有效实现了短钢丝纤维与胎面胶的粘合,复合体综合性能表现良好。     

高强聚乙烯纤维的开发及应用

<正> 一 序言 纤维的强度取决于其线性高分子的取向程度。在纺丝过程中,初生纤维刚喷出纺丝孔,其分子就发生了松弛而使分子链折迭、交络。经拉伸后虽可达到一定取向,但还有相当一部分交络,所以强度不够高。因此,如何使纤维的分子链充分伸展,并沿纤维轴方向排列是合成纤维高强化的努力方向。以芳香族聚酰胺为代表的高强纤维其原料聚合     

炭黑填充胎面胶的动态力学性能研究

对炭黑填充轮胎胎面胶的动态力学性能进行研究.结果表明,炭黑品种对胎面胶玻璃化温度（Tg）的影响不大,但不同品种炭黑填充的胎面胶的损耗因子（tanδ）峰值却明显不同;炭黑N351填充胎面胶的滞后损失较小,冰、湿路面的抓着性能也较好;随着炭黑N351用量的增大,胎面胶的tanδ峰值逐渐降低,Tg向低温方向移动;在20～80℃范围内,炭黑N351用量对胎面胶的储能模量和滞后性能影响较大;当炭黑N351用量为75份时,胎面胶综合性能较好.     

翻新工程机械轮胎胎面胶补强剂的研究

在26.5R25翻新工程机械轮胎胎面胶配方中添加炭黑和白炭黑,研究其对胎面胶的补强效果。结果表明:单一品种炭黑补强胎面胶时,炭黑N151用量为40份时补强效果较佳;炭黑N330与其他品种炭黑并用补强胎面胶时,炭黑N330用量为40份、其他品种炭黑用量为20份时补强效果较佳;炭黑N330与白炭黑并用补强胎面胶时,炭黑N330用量为40份、白炭黑用量为20份时补强效果较为理想,胎面胶的耐磨性能和抗崩花掉块性能均提高;炭黑补强胎面胶机理可应用分子链滑动理论解释,胎面胶中炭黑含量有最佳值,橡胶分子链与炭黑颗粒之间的有效融合吸附阻止了橡胶分子链发生形变和拉伸,从而对橡胶起到补强作用。     

热氧老化对长玻璃纤维增强PP材料动态流变性能影响

通过熔融共混法制备长玻璃纤维增强聚丙烯(LGFPP)复合材料,采用旋转流变仪和扫描电子显微镜测试研究了不同热氧老化时间下复合材料的动态流变行为。结果表明,热氧老化过程PP发生降解,分子量降低,同时随老化程度的加深分子链的缠结以及分子间相互作用力逐渐被削弱,分子链松弛能力增加;树脂的降解过程容易在纤维与基体的界面区域进行,使得纤维与基体的界面性能下降,粘结力下降。因此,随老化时间的增加复合材料的储能模量、损耗模量、损耗因子以及复数黏度都呈现下降趋势。     

The effect of silica (SiO2) nanoparticles and ammonia/ethylene plasma treatment on the interfacial and mechanical properties of carbon-fiber-reinforced epoxy composites

A nanoparticle dispersion is known to enhance the mechanical properties of a variety of polymers and resins. In this work, the effects of silica (SiO₂) nanoparticle loading (0–2 wt%) and ammonia/ethylene plasma-treated fibers on the interfacial and mechanical properties of carbon fiber–epoxy composites were characterized. Single fiber composite (SFC) tests were performed to determine the fiber/resin interfacial shear strength (IFSS). Tensile tests on pure epoxy resin specimens were also performed to quantify mechanical property changes with silica content. The results indicated that up to 2% SiO₂ nanoparticle loading had only a little effect on the mechanical properties. For untreated fibers, the IFSS was comparable for all epoxy resins. With ethylene/ammonia plasma treated fibers, specimens exhibited a substantial increase in IFSS by 2 to 3 times, independent of SiO₂ loading. The highest IFSS value obtained was 146 MPa for plasma-treated fibers. Interaction between the fiber sizing and plasma treatment may be a critical factor in this IFSS increase. The results suggest that the fiber/epoxy interface is not affected by the incorporation of up to 2% SiO₂ nanoparticles. Furthermore, the fiber surface modification through plasma treatment is an effective method to improve and control adhesion between fiber and resin.     

Study on structure and properties of SSBR/SiO2 co‐coagulated rubber and SSBR filled with nanosilica composites

The morphological structure, glass transition, mechanical properties, and dynamic mechanical properties of star‐shaped solution‐polymerized styrene‐butadiene rubber (SSBR) synthesized by a multifunctional organic lithium initiator and SiO₂‐SSBR composite (N‐SSBR) prepared through adding a small amount of nanosilica modified by silane coupling agent to star‐shaped SSBR synthetic solution and co‐coagulating, and their nanocomposites filled with 20 phr nanosilica were investigated, respectively. The results showed that the silica particles were well dispersed with nanosize in N‐SSBR, which glass‐transition temperature (T_g) was 2°C higher than SSBR. N‐SSBR/SiO₂ nanocomposite exhibited lower Payne effect and internal friction loss, higher mechanical properties, and its T_g was 2°C higher than SSBR/SiO₂ nanocomposite. N‐SSBR might promote the dispersion of nanosilica powder in matrix and could be applied to green tire tread materials. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The preparation of microcrystalline cellulose–nanoSiO2 hybrid materials and their application in tire tread compounds

Microcrystalline cellulose (MCC) was hybridized with nano‐SiO₂ to improve its interaction with a rubber matrix. The hybrids (MCC–SiO₂) were prepared with the “microreactor” and “sol–gel” technologies, using MCC as the carrier and tetraethoxysilane as the precursor. The structure and morphology of the hybrids were studied by infrared spectrometry, thermogravimetric analysis, and scanning electron microscopy. The results showed that the nano‐SiO₂ had been loaded successfully on the surface of the MCC with a loading ratio of approximately 30%. The nano‐SiO₂ can take on the morphologies of particles, tubes, or rods by controlling the size of the “microreactor”. The hybrids were then used in silica/SSBR compounds to replace part of the silica, and their effects on the physio‐mechanical and dynamic properties were discussed. The results showed that the vulcanizates with the hybrids had improved physio‐mechanical and dynamic properties. The vulcanizates of MCC–SiO₂ also had a higher wet‐skid resistance and a lower rolling resistance than did the silica vulcanizates when they were used in tire tread compounds. The SEM photos showed that the interfacial adhesion between the MCC and rubber was improved. The size of the MCC hybrids was also in situ decreased during the processing of the rubber compounds. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44796.     

High-temperature mechanical properties of NextelTM 610 fiber reinforced silica matrix composites

Novel Nextel? 610 fiber reinforced silica (N610f/SiO₂) composites were fabricated via sol-gel process at a sintering temperature range of 800–1200?°C. The sintering-temperature dependent microstructures and mechanical properties of the N610f/SiO₂ composites were investigated comprehensively by X-ray diffraction, nanoindentation, three-point bending etc. The results suggested a thermally stable Nextel? 610 fiber whose properties were barely degraded after the harsh sol-gel process. A phase transition in the silica matrix was observed at a critical sintering temperature of 1200?°C, which led to a significant increase in the Young's modulus and hardness. Due to the weak fiber/matrix interfacial interaction, the 800?°C and 1000?°C fabricated N610f/SiO₂ composites exhibited quasi-ductile fracture behaviors. Specially, the latter possessed the highest flexural strength of ≈ 164.5?MPa among current SiO₂-matrix composites reinforced by fibers. The higher sintering-temperature at 1200?°C intensified the SiO₂ matrix, but strengthened the interface, thus resulting in a brittle fracture behavior of the N610f/SiO₂ composite. Finally, the mechanical properties of this novel composite presented good thermal stability at high temperatures up to 1000?°C.     

Fabrication by stereolithography of fiber-reinforced fused silica composites with reduced crack and improved mechanical properties

Chopped quartz fiber-reinforced fused silica (SiO_2f/SiO₂) composites were fabricated by stereolithography. The fiber orientation characteristics and crack distributions after the debinding process of the green bodies were investigated. The results showed that the distribution of fibers presented orientation characteristics; additionally, the number of cracks after debinding decreased as the fiber content increased and the cracks oriented along the fiber orientation. The mechanical properties of SiO_2f/SiO₂ ceramics with different fiber contents were also considered. As a result, a compressive strength of 51.2 MPa and flexural strength of 24.3 MPa were achieved for the SiO_2f/SiO₂ ceramic with 4 wt% fiber, and a sintered cambered structure with a size over 150 mm × 150 mm × 3 mm was fabricated successfully without cracking and deformation for the SiO_2f/SiO₂ composites with a fiber content of 4 wt% and 6 wt%.     

Preparation and performance of oleylamine modified silica-reinforced natural rubber composites

Oleylamine (OA) modified silica (SiO₂-g-OA) was prepared using γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH560) and OA, silica/natural rubber (NR) and SiO₂-g-OA/NR composites were prepared by mechanical blending in an internal mixer, and SiO₂-g-OA was characterized by Fourier transform infrared spectroscopy, thermal gravimetric analyzer, and contact angle analyzer. The mechanical properties, abrasion resistance, curing characteristics, Payne effect, and morphology of silica/NR and SiO₂-g-OA /NR composites were investigated using universal testing machine, Akron abrasion tester, rubber processing analyzer, and scanning electron microscope, respectively. The results showed that SiO₂-g-OA became more hydrophobic and had better compatibility with NR. Moreover, SiO₂-g-OA/NR had weaker Payne effect, better vulcanization performance, and more excellent mechanical properties. As the content of filler was more than 30 phr, SiO₂-g-OA/NR had lower rolling resistance and higher wet skid resistance. Compared with silica modified by other coupling agents, SiO₂-g-OA had the best reinforcement effect on NR.     

Dynamic properties of star‐shaped,solution‐polymerized styrene–butadiene rubber and its cocoagulated rubber‐filled with silica/carbon black

The dynamic properties, including the dynamic mechanical properties, flex fatigue properties, dynamic compression properties, and rolling loss properties, of star‐shaped solution‐polymerized styrene–butadiene rubber (SSBR) and organically modified nanosilica powder/star‐shaped styrene–butadiene rubber cocoagulated rubber (N‐SSBR), both filled with silica/carbon black (CB), were studied. N‐SSBR was characterized by ¹H‐NMR, gel permeation chromatography, energy dispersive spectrometry, and transmission electron microscopy. The results show that the silica particles were homogeneously dispersed in the N‐SSBR matrix. In addition, the N‐SSBR/SiO₂/CB–rubber compounds' high bound rubber contents implied good filler–polymer interactions. Compared with SSBR filled with silica/CB, the N‐SSBR filled with these fillers exhibited better flex fatigue resistance and a lower Payne effect, internal friction loss, compression permanent set, compression heat buildup, and power loss. The nanocomposites with excellent flex fatigue resistance showed several characteristics of branched, thick, rough, homogeneously distributed cross‐sectional cracks, tortuous flex crack paths, few stress concentration points, and obscure interfaces with the matrix. Accordingly, N‐SSBR would be an ideal matrix for applications in the tread of green tires. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40348.     

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) nanocomposites with optimal mechanical properties

With the ultimate goal to design renewable polymer nanocomposites with optimal mechanical properties, this study reports an investigation of structure–property relationships for a model system – silica/poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHx) nanocomposites. Two molecular weights of PHBHx (M_w = 903,000 g/mol and M_w = 633,000 g/mol) and two types of silica nanoparticles (nominally spheres and fibers according to the manufacturer) were used to prepare the nanocomposites. Small-angle X-ray scattering shows that the sphere and fiber nanoparticles had similar surface areas and primary particle size, but differed in degree of aggregation of the primary particles. The thermal stability of the PHBHx matrix was slightly improved by the addition of nanofillers. Simultaneous improvement of both stiffness and toughness was observed at 1-wt% loading for the higher molecular weight matrix. The more highly aggregated SiO₂ fibers had a greater toughening effect than the SiO₂ spheres. Compared to the unfilled polymer matrix, a 30% increase in Young's modulus and 34% increase in toughness were obtained for the 1-wt% SiO₂ fiber/PHBHx072 nanocomposite. The addition of SiO₂ spheres to PHBHx072 resulted in the same increase in Young's modulus (30%) but a smaller increase (11%) in toughness. The dramatic increases in modulus for PHBHx072 cannot be explained on the basis of two-component micromechanical models. Apparently the filler alters the character of the semicrystalline matrix. When the loading was 3 wt% and above, Young's modulus continued to increase, but the strain at break and toughness decreased. The ultimate strength did not change compared with the unfilled polymer. In order to understand the mechanical properties observed, the thermal behavior, spherulitic morphology and the deformation mechanisms of the nanocomposites and the dispersion state of the nanofillers were studied. We found that a high molecular weight of the polymer matrix, weak interfacial adhesion and a good dispersion of the nanofillers are necessary to improve toughness and stiffness simultaneously.     

Aramid‐short‐fiber reinforced rubber as a tire tread composite

Mechanical and dynamic‐mechanical properties of a typical tire tread compound reinforced with one part aramid short fibers were investigated in order to predict the effects of fibers on tire tread performances such as rolling resistance and traction. Rubber processing, including mixing and extrusion, was performed in an industrial scale. Fiber orientation as a result of extrusion was evaluated quantitatively and qualitatively using mechanical anisotropy in swelling and scanning electron microscopy, respectively. Unidirectional tensile tests revealed higher modulus, but slightly lower strength and elongation at break for the composites stretched in the longitudinal (orientation) and transverse directions than those for the isotropic reference compound with no fiber. Dynamic mechanical thermal analysis showed that relative values of loss factor for the longitudinal and transverse composites and the reference compound depended on the state of polymer as glassy or rubbery. Therefore, a high loss factor at lower temperatures and a low loss factor at higher temperatures predicted a balanced improvement of tire traction and rolling resistance as a result of fiber addition. Heat build‐up and abrasion experiments showed that addition of fiber did not deteriorate other performances of tire tread. Also, the fibers had negligible effects on processing and vulcanization characteristics of the composite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Mechanical and rheological properties of silica-reinforced polypropylene/m-EPR blends

Rheological and mechanical properties (tensile and impact properties) as well as the mechanical profiles of ternary isotactic polypropylene/silica/elastomer (iPP/SiO₂/m-EPR metallocene catalyzed ethylene-propylene rubber) composites were investigated and discussed. The effects of two metallocene ethylene-propylene-based elastomers (m-EPR) differing in molecular weight/viscosity and their content on iPP/silica composites with different silica types differing in size (nano- vs. micro-) and surface properties (untreated vs. treated) were investigated. The two m-EPR elastomers were added to iPP/SiO₂ 96/4 composites as possible impact modifier and compatibilizer at the same time in 5, 10, 15, and 20 vol% per hundred volume parts of composites. The effects of different silica fillers and two m-EPR rubbers were discussed within the context of structure-morphology-mechanical property relationships of these iPP/SiO₂/m-EPR composites. Tensile and impact strength properties were mainly influenced by combined competetive effects of stiff filler and tough m-EPR elastomer so sinergistic effect was also observed. The ductility of these composites was affected additionally by spherulite size of the iPP matrix due to the difference in nucleation abilities of silica fillers enabled by prevailing separated morphology observed in iPP/SiO₂/m-EPR composites.