非织造工艺对天然纤维增强体树脂流动性能的影响

纤维增强体的树脂流动性能是影响树脂传递模塑工艺设计及其复合材料质量的一个重要因素。本文利用单向法测试真空辅助传递模塑工艺中非织造工艺对亚麻纤维增强体对树脂流动性能的影响。结果表明,相同压力条件下,由平行铺网工艺制作的纤维增强体比交叉铺网工艺增强体树脂渗透率低,流动各项异性大;随着层数的增加及压力的增大,两种铺网工艺增强体的树脂渗透率降低,压力的变化对流动各向异性影响不大。     

热处理对EP/CF及EP/CF/GF复合材料力学性能的影响

采用真空辅助树脂转移模塑（VARTM）技术制备了环氧树脂/碳纤维（EP/CF）和环氧树脂/碳纤维/玻璃纤维毡（EP/CF/GF）复合材料。测试了两种纤维铺层方式中树脂流动距离的平方与流动时间的关系,对两种铺层纤维体系的渗透率进行了研究对比;将两种复合材料进行高温处理,并且对其高温处理前后的力学性能进行分析;利用扫描电子显微镜（SEM）观察了复合材料的拉伸断口形貌。结果表明,EP/CF/GF中GF毡的松散结构使树脂更易流动;高温热处理造成了EP/CF弹性模量和拉伸应变的降低,其中弹性模量降低了9.97 %、拉伸应变降低了11.36 %,但对EP/CF/GF的影响较小;GF毡的加入造成了2种复合材料弯曲性能的下降;未经处理的复合材料断口表面光滑,而热处理后的复合材料断口表面粗糙且有大量基体附着。     

导流介质对VARTM复合材料纤维分布及空隙率的影响

研究了导流介质尺寸对真空辅助树脂传递模塑(VARTM)工艺中树脂流动行为的影响,以及对复合材料制品中纤维分布和空隙率的影响。结果表明,随着导流介质尺寸的增加,树脂在增强体中的流动速度加快,并呈现指数加速趋势;制品中纤维体积含量呈现先减少后增大的趋势,并且以导流介质边界为纤维体积含量高低的分界线;复合材料制品的空隙率范围在3.86%~19.92%,空隙率呈现先增大后减小再加速增大的趋势。     

苯乙烯对植物纤维渗透性及UP复合材料成型质量影响

为提高真空辅助树脂注射成型工艺制备植物纤维增强复合材料的生产效率和成型质量,以苯乙烯为稀释剂,以不同黏度不饱和聚酯树脂(UP)和苎麻织物制备苎麻织物增强UP复合材料。基于达西定律研究UP黏度对苎麻增强体渗透率的影响,结合复合材料纤维体积分数、力学性能以及内部缺陷对复合材料成型质量进行分析。结果表明,随着UP黏度降低,增强体的渗透性呈近似指数增加,纤维膨胀效应逐渐增大,而力学性能先升高后降低,这与苯乙烯交联单体固化机理相关;黏度为360 mPa·s的UP制备的复合材料综合性能最优,其渗透率、拉伸强度、拉伸弹性模量、弯曲强度、弯曲弹性模量和剪切强度相比黏度为440 mPa·s的UP制备的复合材料,分别提高22.22%,20.80%,12.05%,5.44%,7.58%和8.27%;UP黏度降低改善了纱线内部UP流动的滞后性,UP复合材料内部的缺陷减少。     

复合材料的真空辅助成型工艺研究

研究了导流介质、脱模介质等工艺要素对真空辅助成型工艺的影响。结果表明,高渗透率的导流介质和脱模介质均能有效提高树脂的充模速度;所研制的新型导流介质能够有效控制树脂的流动状态。采用真空辅助成型工艺成型的复合材料的性能与模压工艺成型的复合材料的性能相当。     

偏轴向角度对复合材料力学性能的影响

采用真空辅助树脂传递模塑工艺(VARTM)制备了纤维增强复合材料标准试样,表征了纤维增强复合材料在不同偏轴向角度下的拉伸性能和弯曲性能,考察了载荷方向和偏轴向角度对纤维增强复合材料的冲击韧性、压缩性能的影响,分析总结了纤维增强复合材料的性能与偏轴向角度之间的关系,为纤维增强复合材料在工程上的应用提供了技术支撑。     

三维织物厚度方向渗透率研究

复合材料的液体成型特点是树脂需在复杂结构纤维预制体中流经较长的距离,故探讨树脂在纤维织物中的流动行为尤为重要。研究了三维织物厚度、纤维细度以及纤维体积分数对类树脂液体在厚度方向渗透行为的影响,并分析了相关的流动行为规律。研究结果表明:当织物厚度较小时,树脂的渗透率随织物厚度增加而迅速下降;当织物厚度达到阈值时,渗透率因织物中孔隙减少而趋于定值。当织物的纱线细度降低时,纤维束间孔隙增大,使纤维束形状和结构发生改变,故渗透率增大;当织物厚度方向的压缩量增加时,纤维束间孔隙减少,孔隙形状趋于扁平,流动通道减少,故渗透率降低。     

电热耦合作用对含预置损伤CFRP层合板剩余强度的影响

基于实验室自制电热耦合测试平台,获得含预置分层与预置纤维断裂碳纤维增强树脂基复合材料(CFRP)层合板的表面电热温度场分布,并对不同电热耦合作用后的复合材料层合板试样进行了弯曲性能测试,结合失效模式分析,探究了电热耦合作用对含预置损伤CFRP层合板剩余强度的影响及作用机制。研究结果表明：不同的损伤形式对电热响应温度场存在明显影响;相比于完好试样,分层试样与纤维断裂试样的弯曲性能和树脂基体的性能更为相关,电热耦合作用导致的后固化效应对两类预置损伤试样的性能提升效果更为明显,缓解了由预置损伤导致的性能劣化。     

芳纶包覆碳纤维增强环氧树脂的轴向压缩性能研究

采用缠绕法制备了芳纶长丝包覆碳纤维束,利用真空辅助树脂转移成型法制备了包覆碳纤维增强环氧树脂.通过电子万能试验机测试了复合材料的轴向压缩性能,研究了长丝缠绕方式、包覆密度和碳纤维束的数量对试样压缩强度及破坏模式的影响.结果表明,芳纶包覆能够提升碳纤维复合材料的压缩强度,随着芳纶长丝包覆密度的增加,压缩强度逐渐增加;相比...     

亚麻针刺毡/不饱和树脂复合材料的制备与研究

本文主要研究了亚麻纤维非织造物作为复合材料的增强体,采用真空辅助树脂传递模塑法(VARTM)与不饱和树脂复合成板材.最后对复合材料板材进行拉伸性能测试和力学性能比较.     

Effect of fiber surface treatment on the properties of biocomposites from nonwoven industrial hemp fiber mats and unsaturated polyester resin

Biocomposites were made with nonwoven hemp mats and unsaturated polyester resin (UPE). The hemp fiber volume fraction was optimized by mechanical testing. The effect of four surface treatments of industrial hemp fibers on mechanical and thermal properties of biocomposites was studied. The treatments done were alkali treatment, silane treatment, UPE (matrix) treatment, and acrylonitrile treatment. Bending strength, modulus of elasticity, tensile strength, tensile modulus, impact strength, storage modulus, loss modulus, and tan δ were evaluated and compared for all composites. The mechanical as well as thermal properties of the biocomposites improved after surface treatments. The properties of the above biocomposites were also compared with E‐glass–mat composite. To achieve balance in properties, a hybrid composite of industrial hemp and glass fibers was made. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1055–1068, 2006     

Surface modification of ABS with Cr6+ free etching process in the electroless plating

ABS resin is widely used after the plating process. The traditional ABS resin surface etching process uses a chromic acid system, which is a great threat to environmental protection. This paper examines a new environment-friendly measure in the etching system, which is composed of HNO₃, H₂SO₄, and NiSO₄. With this system, the solution will be etching at 60?°C for 20?minutes on an ABS resin surface and causing the surface roughness of the ABS resin to become larger, and an increase of hydrophilicity. It is observed that the root mean square (RMS) of the surface roughness of the ABS resin increased from 3.21?nm to 27.5?nm after etching, and the surface contact angle of ABS resin decreased from 88.04° to 65.29°. After the etching process, the surface of ABS can be electroless plated successfully and the bonding force of coating and resin can reach 2.09 MPa. The FT-IR spectra and XPS analyses showed that hydroxyl and nitro groups on the ABS surface are as a result of etching treatment, which improves the bonding strength between ABS substrate and electroless copper plating. This new etching system can be a substitute for the traditional chromic acid system in the industry, which will greatly reduce the pollution caused by the traditional process.     

Surface modification of ABS by photocatalytic treatment for electroless copper plating

Surface roughness of acrylonitrile–butadiene–styrene (ABS) resin prior to metallization is treated generally with sulphuric/chromic acid system. However, the presence of chrominum (VI) ion imposes serious environmental problems. In this work, TiO₂ photocatalytic treatment was used to enhance the adhesion strength between the ABS surface and the electroless copper film. Effects of the TiO₂ content, irradiation time and UV power upon the surface topography, surface characterization and the adhesion strength were investigated. The results indicated that the surface hydrophilicity of ABS resin and the adhesion strength between the electroless copper film and ABS surface increased with an increase in the UV power and a prolongation in irradiation time, and did not increase linearly with an increase of TiO₂ content. Though the surface topography of ABS changed little, the adhesion strength reached 1.25?kN/m, which was higher than that in the optimal H₂SO₄–MnO₂ colloid. The surface chemistry results indicated that –COOH and –OH groups formed with the photocatalytic treatment and the absorption strengths increased with the UV power. XPS analysis results further demonstrated that the contents of C=O and –COOH reached 6.4 and 4.9% with the photocatalytic treatment, which was much higher than that of the H₂SO₄–MnO₂ colloid (3.9 and 3.1%). The high contents of C=O and –COOH groups enhanced the surface hydrophilicity of the ABS resin and improved the adhesion strength between the electroless copper film and ABS resin. The results indicated that the photocatalytic treatment was an environment-friendly and effective method to replace the commercial wet chemical process for ABS surface modification.     

Effect of Components upon the Surface Area of Woodceramics

The surface area of woodceramics, a novel porous material, plays an important role in catalysis, water treatment and air filtration etc. In the present study, the effect of components of the woodceramics, i.e., cellulose, lignin and phenolic resin, upon the surface area of woodceramics was investigated. The experimental results showed that cellulose, lignin and phenolic resin represented quite different carbonization ratios and surface areas during the carbonization. The results also indicated that lignin and phenolic resin were prone to carbon precipitation during heat treatment, compared with cellulose. It was deduced that the surface area of the woodceramcis depended on the amounts of the cellulose, lignin in the raw woody material, the amount of the phenolic resin and the carbonization temperature.     

改性氮化铝/环氧树脂复合材料的制备研究

采用共混-浇注成型法制备氮化铝/环氧树脂AlN/E-51复合材料。借助静止沉淀法、接触角、傅立叶红外光谱FT-IR和热失重TGA等进行分析表征。探讨了AlN用量和表面改性对复合材料力学性能的影响。结果表明,KH-560以化学键结合在AlN表面。复合材料的弯曲和冲击强度均随AlN用量的增加而提高,当AlN用量为10%时,复合材料的力学性能最佳。()()()     

改性色谱分离树脂的制备及在果糖分离中应用

通过直接对KRS-1色谱分离树脂进行表面氟化改性,调节氟的加量,使氟原子在树脂骨架上分布,在树脂表层形成橡胶弹性体,试验证明,该氟化改性色谱分离树脂用于果葡糖浆中果糖分离,果糖质量分数及分离度均高于未氟化树脂,力学性能也得到提高,树脂破碎率远低于未氟化树脂.最适宜氟化试验反应条件为:V(N2)∶V(F2)为9∶1,氟气...     

纳米CaCO3填充环氧树脂分散技术研究

对纳米CaCO3填充环氧树脂的均匀分散技术进行了探讨。采用超声波振动和对纳米CaCO3进行硅烷偶联处理两种方法改进CaCO3在环氧树脂中的分散效果。扫描电镜观察表明，以上两种方法比普通搅拌混合效果更好，实现了纳米CaCO3在环氧树脂中的均匀分散。     

Kevlar纤维的表面改性研究

采用甲苯-2,4-二异氰酸酯(TDI)和环氧树脂(EP)混合制得的表面改性剂对Kevlar纤维进行表面接枝处理,利用扫描电子显微镜观察Kevlar纤维改性前后的表面形貌及改性Kevlar纤维与弹性体间剥离界面的破坏形貌,用衰减全反射傅里叶变换红外光谱仪分析Kevlar纤维改性前后表面化学基团的变化,研究了改性效果和机理。结果表明,TDI和EP发生了化学反应,改性剂可在Kevlar纤维表面引入活性基团,从而显著改善了Kevlar纤维与聚合物基体之间的界面粘合状态。     

酸化处理对纳米碳纤维及其复合材料性能的影响

本文采用浓酸(浓硫酸/浓硝酸)氧化法对纳米碳纤维进行表面处理,在水热和超声分散条件下,制备纳米碳纤维/环氧树脂复合材料.X射线光电子能谱分析表明,酸化处理在纳米碳纤维表面引入了羟基和羧基等能参与环氧树脂固化反应的官能团.流变试验结果表明,酸化处理在一定程度上提高了复合材料流体的流动性.断裂韧性测试结果和扫描电子显微镜(SEM)分析也显示了酸化处理能有效改善纤维与树脂的界面结合状况,提高复合材料的断裂韧性.     

低表面能树脂的性能及固化研究

通过化学改性,合成了环氧树脂/有机硅复合树脂。探讨了不同固化剂及其复配方式对其固化性能的影响,并得到最佳的固化剂配方。通过红外光谱（IR）、扫描电子显微镜（SEM）、动态力学分析（DMA）以及接触角测试,研究并比较了改性前后有机硅树脂涂层的微观结构形貌、体系混溶性、表面性能（接触角）等的变化。研究结果表明：环氧树脂与有机硅树脂之间具有较好的微观混溶性;改性后,树脂表面的粗糙度增加,接触角增大,形成低表面能树脂。