国产T700级碳纤维/双马来酰亚胺树脂复合材料界面性能

分别以日本东丽T700S和国产T700级碳纤维作为增强体,采用热压罐成型工艺制备了双马来酰亚胺树脂基复合材料。对比研究了两种碳纤维表面物理、化学状态以及复合材料的微观界面性能、层间剪切性能。结果表明,国产T700级碳纤维表面沟槽结构分布较多,表面粗糙度较高,有利于与树脂基体形成更好的物理结合作用。虽然两种碳纤维的含氧官能团相当,但国产T700级碳纤维表面元素氧碳比较高,有利于与基体树脂形成更好的化学结合作用,其界面剪切强度较T700S碳纤维复合材料高约14%,复合材料的层间剪切强度高约19%。     

不同热塑性树脂基体对单向碳纤维复合材料吸湿行为的影响

采用溶液浸渍和热压成型分别制备了以聚醚砜和聚醚砜/聚苯硫醚为基体的单向连续碳纤维增强复合材料,研究了不同成型温度下复合材料的层间剪切强度和湿热环境下对水分的吸湿过程。结果表明,添加了聚苯硫醚的复合材料在较佳的加工工艺窗口下可以保持原有的层间剪切强度,同时大幅度地增强复合材料的抗水分侵蚀能力。这是由于聚苯硫醚在热压成型过程中,以聚醚砜为晶核在碳纤维表面结晶,形成较为致密的结构。同时红外分析表明,混合树脂极性较小。二者共同作用,可以提高复合材料在使用过程中的安全性和结构的完整性。性能较好的复合材料吸湿过程符合Fick第二定律。     

热压工艺对单向连续碳纤维增强聚苯硫醚/聚醚砜复合材料力学性能的影响

将溶液浸渍法和悬浮液浸渍法结合,通过热压成型制备了以聚苯硫醚/聚醚酚为基体的单向连续碳纤维增强复合材料,研究了不同树脂浓度和热压工艺参数下复合材料的力学性能。结果表明:在以12.5%质量浓度的PES-DMAc溶液体系中,以聚苯硫醚和聚醚砜质量比为1:3复配树脂构成的复合材料综合力学性能优于以单一聚醚砜为基体的复合材料。通过层间剪切强度、弯曲强度、压缩强度和冲击强度的测试,确定了复合材料的最佳加工工艺参数,利用扫描电镜分析了复合材料的在受力断裂时的破坏机理。     

国产T800碳纤维/双马来酰亚胺复合材料的界面及力学性能

分别采用日本东丽T800H和国产T800碳纤维作为增强体,采用热压罐工艺制备双马来酰亚胺树脂基复合材料。研究了2种碳纤维的表面物理和化学状态,复合材料的微观界面性能及力学性能。结果表明:国产T800碳纤维表面沟槽分布较多,表面粗糙度较高,有利于与树脂基体形成更好的物理结合作用。同时,国产T800碳纤维表面具有较多的含氧官能团,有利于与基体树脂形成更好的化学结合作用。因此,国产T800碳纤维的界面剪切强度较T800H碳纤维高约27%。国产T800/HT-280复合材料的力学性能均普遍高于T800H/HT-280复合材料,其中,90°拉伸强度高约25%,面内剪切强度、弯曲强度高约12%,层间剪切强度高约7%。     

湿法缠绕用T800碳纤维复合材料基体研究

针对T800碳纤维和湿法缠绕的特点,开发了一种适合T800碳纤维湿法缠绕用的树脂基体,测试了该树脂基体与T800碳纤维制成复合材料的力学性能和耐湿热性能。结果表明,该树脂体系的粘度和适用期可满足湿法缠绕成型工艺要求,制备的T-800碳纤维复合材料界面粘接好,层间剪切强度达到101 MPa,NOL环拉伸强度高于2500MPa;单向复合材料经95℃蒸馏水浸泡150h后的平衡吸湿率低于1%、力学性能保留率高,耐湿热性能优良。     

Z向增强平纹编织C/SiC复合材料层间剪切强度(英文)

碳纤维平纹编织物和穿透厚度的碳纤维Z-pins制作的预成型体,通过化学气相渗透工艺制备了Z-pins增强平纹编织C/SiC复合材料。采用双缺口剪切压缩试验测定了Z-pins增强平纹编织C/SiC复合材料的层间剪切强度,通过断口的电镜照片分析了层间剪切的破坏机理。研究了Z-pins个数对层间剪切强度的影响。结果表明:与未增强陶瓷基复合材料相比较,当Z-pins个数达到一定数量时,Z-pins插入能够提高层间剪切强度,层间剪切强度随Z-pins个数的增多而增加。Z-pins插入改变了陶瓷基复合材料的层间破坏机理,使层间织物与基体的脱离变为Z-pins的剪切破坏和层间织物与基体脱离的双重破坏机制。     

硅烷偶联剂对电子束固化碳纤维复合材料界面的增效研究

根据碳纤维表面的特点及其复合材料中树脂基体进行电子束固化的机理,对碳纤维表面进行预氧化以提高碳纤维表面含氧宫能团的含量,利用偶联剂的化学架桥作用对电子束固化复合材料界面进行了增效研究.采用X射线光电子能谱(XPS)对处理后碳纤维表面化学成分进行了分析,并采用层间剪切强度对电子束固化复合材料界面粘合性能进行了评价.结果表明,碳纤维表面的含氮官能团使电子束固化复合材料中碳纤维与环氧树脂基体之间的粘合强度减弱,偶联剂与预氧化碳纤维表面进行了强相互作用,使电子束固化复合材料层间剪切强度得到提高.     

PEK-C膜层间增韧碳纤维/环氧树脂复合材料的力学性能

为探究热塑性酚酞基聚醚酮（Polyaryletherketone with Cardo，PEK-C）树脂薄膜及膜厚对层间增韧碳纤维/环氧树脂复合材料力学性能的影响，利用浸渍提拉法制备了三种不同厚度（分别约为1 μm、10 μm、30 μm）的PEK-C膜，通过热压成型制备了层间增韧碳纤维/环氧树脂复合材料层合板，对其进行了Ⅰ型层间断裂韧性、冲击后压缩强度、层间剪切及弯曲性能测试，并利用SEM观察微观形貌及AFM扫描微观相图。结果表明：不同PEK-C膜厚增韧碳纤维/环氧树脂复合材料的Ⅰ型层间断裂韧性、冲击后压缩强度及层间剪切强度有不同程度提高，Ⅰ型层间断裂韧性及层间剪切强度以膜厚为10 μm最佳，分别增大了157.17%和17.57%，冲击后压缩强度以膜厚为30 μm最佳，达到了186.67 MPa，这是由于PEK-C与环氧树脂在热压固化过程中形成了双相结构，改善了材料韧性；但弯曲性能持续下降，强度及模量由未增韧的1 551 MPa、106 GPa分别降至30 μm时的965 MPa、79 GPa，这是由于PEK-C树脂扩散进入环氧树脂中，降低了纤维体积分数及材料刚度。     

硅烷偶联剂对电子束固化碳纤维复合材料的增效研究

根据碳纤维表面的特点及其复合材料中树脂基体进行电子束固化的机理,对碳纤维表面进行预氧化以提高碳纤维表面含氧官能团的含量,利用偶联剂的化学架桥作用对电子束固化复合材料界面进行了增效研究。采用X射线光电子能谱（XPS）对处理后碳纤维表面化学成分进行了分析,并采用层间剪切强度对电子束固化复合材料界面粘合性能进行了评价。结果表明,碳纤维表面的含氮官能团使电子束固化复合材料中碳纤维与环氧树脂基体之间的粘合强度减弱,偶联剂与预氧化碳纤维表面进行了强相互作用,使电子束固化复合材料层间剪切强度得到提高。     

碳纤维在电子束辐射过程中对树脂基复合材料界面性能的影响

采用XPS和Raman分析了电子束辐射对碳纤维表面性质的影响，研究了碳纤维与基体树脂之间的不充分接触对电子束固化复合材料层间剪切强度的影响，同时分析了碳纤维表面吸附的水分，碳纤维与基体树脂之间的空隙率和碳纤维表面在碳酸氢铵电解液中进行阳极氧化处理后对电子束固化复合材料界面性能的影响，分析了碳纤维表面在电子束辐射过程中与树脂基体的作用机理。     

聚对苯撑苯并二(口恶)唑原纤化纳米纤维制备技术及结构性能

聚对苯撑苯并二(口恶)唑(PBO)纤维是一种具有多重原纤结构的高分子聚合物.通过机械力作用可以使PBO纤维发生原纤化,制备具有直径小于100 nm的PBO原纤化纳米纤维.文中对PBO纤维发生原纤化的历程及机理进行研究,扫描电镜观察发现PBO纤维的原纤化过程包括:脱除皮层、主干破坏、进一步原纤化等阶段,剥离和劈裂是原纤化的主要方式.经过原纤化处理的PBO纤维,呈现不同尺寸纤维组成的多分散体.打浆度70°SR的PBO原纤化纳米纤维的直径可达到50 nm,其保水值118％,纤维长度分布主要集中在0.3～0.5 mm,比表面积21.89 m2/g.以PBO原纤化纳米纤维为原料,通过湿法成形方式在抄纸系统上制备的纸基材料力学性能随着原纤化程度增加而增加.     

Mathematical Analysis of Resin Flow through Fibrous Porous Media

Resin flow through fiber preforms was analyzed mathematically. Closed form solutions for fiber volume fraction distribution and pressure field during resin infusion into fiber preforms were suggested, and a new effective permeability was defined. The effect of preform compressibility on the fiber volume fraction and pressure distributions in resin-saturated region was investigated analytically. The findings show that the compaction behavior of preforms has significant impact on the resin infusion process. The solutions derived analytically in this study can provide insight into a liquid composites molding (LCM) process.     

A numerical simulation of the resin film infusion process

A numerical analysis was conducted for the resin film infusion (RFI) process using semi-cured thermosetting resin films. Mathematical models were developed for the compression of fiber and the viscosity of resin. The force balance between the fiber preform and the resin was considered to account for the deformation of fiber preform and the swell of fiber during the infusion. In an effort to locate the optimal process conditions such as the mold temperature, the fiber volume fraction, and the infusion pressure, a parametric study was carried out for the progression of resin and the infusion time for different process conditions. The numerical code developed in this study was found to be useful in determining the maximum height of vertical sections that can be infused by squeezing the liquefied resin film from the base panel.     

Processing of PLA/sisal fiber biocomposites using direct- and extrusion-injection molding

The processing strategy adopted to develop biocomposites plays a significant role in determining their characteristics. The present experimental investigation explores the feasibility of using direct-injection molding (D-IM) process for processing of sisal fiber (3?mm and 8?mm) reinforced poly-lactic acid biocomposites with a fiber weight fraction of 30%. For a comparative analysis, mechanical and morphological behavior of biocomposites developed using D-IM process is compared with biocomposites developed using extrusion-injection molding (E-IM) process. The mechanical behavior in terms of tensile, flexural and impact properties is compared and discussed in relation to extracted fiber morphology and fiber orientation as well as dispersion within the developed biocomposites. Morphological investigation of extracted fibers revealed severe fiber attrition and fiber length variation during E-IM process as compared with D-IM process. However, short sisal fiber (3?mm) reinforced biocomposites developed using both the processes exhibit uniform fiber dispersion and orientation, resulting in comparable mechanical properties. The tensile and flexural strength of D-IM-SF biocomposites increased remarkably by 34.7% and 15.9%, respectively, as compared with D-IM-LF biocomposites. Similarly, the tensile and flexural modulus of D-IM-SF biocomposites increased significantly by 92.5% and 56.7%, respectively, as compared with D-IM-LF biocomposites. However, D-IM process incorporating long fibers exhibit better impact properties.     

Effect of YSZ fiber addition on microstructure and properties of porous YSZ ceramics

Yttria-stabilized zirconia (YSZ) fiber was introduced as the reinforcement for porous YSZ ceramics fabricated by tert-butyl alcohol-based gel-casting process and pressureless sintering. Effect of YSZ fiber addition on the microstructure and properties of porous YSZ ceramics was studied systematically. Results showed that YSZ fiber obviously obstructed densification during the sintering process and therefore higher porosity could be achieved with the same solid loading of the initial slurry. Mean pore size regularly increased with increasing fiber addition. The reinforcing effect reached its optimum with 10 wt% YSZ fiber addition, yet decreased with increasing porosity. Fiber addition significantly changed the fracture mode of the porous ceramics from brittle to quasi-ductile with increasing fiber additions; fiber pull-out and crack deflection play major roles in the process. Compared with the porous ceramics without fibers, the thermal conductivity decreased a little. With improved mechanical and thermal properties, YSZ fiber-reinforced porous YSZ ceramics are more applicable in thermal insulation materials.     

Controlling of the interfacial shear strength between thermoplastic resin and carbon fiber by adsorbing polymer particles on carbon fiber using electrophoresis

In order to control the interfacial adhesion between carbon fibers and thermoplastic resins, poly(methyl methacrylate) (PMMA) particles have been adsorbed on the carbon fiber surfaces using an electrophoresis process. The amount of PMMA particles adsorbed on the modified carbon fibers was varied using the electrophoresis technique performed in polymer colloids for a short time. Additionally, the interfacial shear strength between the modified carbon fiber and the resin was controlled by a modification of the present process. An improved interaction and a strengthened surface adhesion between the carbon fiber coated with particles and the PMMA resin were observed.     

涤纶短纤维在纺程中的XRS、DMA研究

应用ＦＲＳ－ＸＲＳＡ、ＳＡＸＳ、ＤＭＡ等研究了涤纶短纤维在纺丝及后处理过程中的结晶,取向与超结构的形成与变化,并讨论了涤纶纤在后加工过程中玻璃化温度与纤维聚集态结构的关系。     

Tensile strength enhancement in interground fiber cement composites

Interground fiber cement (IFC) is a new process where fibers are ground in with the cement clinker during the dry cement manufacturing process. With IFC considerable strength enhancement can be achieved compared to ordinary cement even at a fiber volume as low as 0.2% due to homogeneous fiber distribution and fiber surface modifications associated with the milling process. The cracking mechanisms associated with the strength enhancement were observed in real time during load application using a custom designed loading device. The homogeneous fiber distribution stabilizes crack growth. Formation of multiple, stable secondary microcracks was observed during the strain hardening regime, enhancing the strain capacity at ultimate strength. Fiber pullout was the dominant toughening mechanism in the strain softening regime. For fibers inclined to the propagating crack, fiber pullout was preceded by secondary microcrack formations along the fiber/matrix interface.     

三维编织超高分子量聚乙烯纤维-碳纤维混杂增强环氧树脂复合材料摩擦磨损性能

以超高分子量聚乙烯纤维(UHMWPE)-碳纤维(CF)三维混杂编织体为增强体，环氧树脂(ER)为基体，通过树脂传递模塑(RTM)工艺制备了三维编织混杂复合材料，研究了其摩擦磨损性能了，并采用混合正压力模型对摩擦系数进行了预测。结果表明，在纤维总体积含量一定的情况下，随着CF体积含量的增加，复合材料的摩擦系数增大，而其比磨损率降低。UH_3D/ER复合材料的磨损机制以粘着磨损为主，CF_3D/ER复合材料则以磨粒磨损为主，混杂复合材料的磨损机制主要取决于CF与UHMWPE纤维的相对含量 ,通过调节UHMWPE纤维和CF的体积比例可实现对复合材料摩擦磨损性能的有效调控。采用的计算模型可较好地预测UH_3D/ER的摩擦系数。     

生物质全降解材料微观组织结构与性能关系研究

以采用植物纤维(稻草纤维)、淀粉为主料,通过发泡成型工艺制成的生物质全降解材料为研究对象,研究了该材料在成型过程中气泡孔的生长机理,并采用扫描电子显微镜微区化学分析技术对4种植物纤维、淀粉、发泡剂不同含量的生物质全降解材料微观组织结构进行实验研究。结果表明生物质全降解材料中的植物纤维的连接形式是相互交叉的立体网状结构;发泡剂含量为1.0%时,生物质全降解材料形成的气泡孔为封闭结构且分布比较均匀,这种均匀的结构保证了材料良好的抗冲击性、反弹性和隔热保温性。