i-PP-g-MAH对i-PP/CaSO4复合材料的影响

用在50 L固相接枝反应器中合成的马来酸酐接枝聚丙烯(i-PP-g-MAH)作界面改性剂,制备了马来酸酐接枝聚丙烯/聚丙烯/硫酸钙晶须(i-PP-g-MAH/i-PP/CaSO4)复合材料.研究了i-PP-g-MAH/i-PP/CaSO4 复合材料的形态结构和力学性能.结果表明:i-PP-g-MAH对i-PP/CaSO4复合物的缺口抗冲强度、弯曲强度和拉伸强度均有增强作用;i-PP-g-MAH对硫酸钙晶须填充的i-PP/CaSO4复合物表观粘度几乎没有影响.SEM观察发现iPP-g-MAH对硫酸钙晶须填充的i-PP/CaSO4复合物相界面有明显的改善.     

界面强度对纤维复合材料破坏及力学性能的影响

界面作为复合材料中的重要组成部分对其宏观力学性能及破坏模式有着不可忽视的影响. 本文采用自组装薄膜技术对玻璃纤维表面改性, 得到不同表面性质的玻璃纤维, 与环氧树脂基体复合得到不同界面强度的复合材料. 利用带偏光显微镜的拉伸仪, 研究在不同界面强度下玻璃纤维/环氧树脂基复合材料的破坏过程及力学性能. 结果表明, 复合材料在强界面情况下发生脆性破坏, 在弱界面情况下发生韧性破坏, 且增强纤维对复合材料性能的增强效果与界面强度有关.     

原位共聚改性Mg(OH)2/PP复合材料的微观结构与性能

采用乙烯基硅烷在氢氧化镁晶须（MH）表面引入乙烯基后与不同单体进行原位聚合,制备了改性氢氧化镁晶须（MMH）,通过熔融复合与注射成型的方法制备了聚丙烯/晶须（PP/MH）复合材料,并对复合材料的结构与性能进行了表征.结果表明：原位聚合改性增强了MH与PP之间的界面相互作用力,提高了PP/MH复合材料的冲击强度;填充甲基丙烯酸甲酯（MMA）/丙烯酸丁酯（BA）共单体原位聚合改性MH与MMA原位聚合改性MH相比,PP/MMH复合材料的拉伸强度和冲击强度均有显著提高.     

i-PP-g-MAH对i-PP／CaSO4复合材料的影响

用在50L固相接枝反应器中合成的马来酸酐接枝聚丙烯(i-PP-g-MAH)作界面改性剂，制备了马来酸酐接枝聚丙烯／聚丙烯／硫酸钙晶须(i-PP-g-MAH／i-PP／CaSO4)复合材料．研究了i-PP-g-MAH／i-PP／CaSO4复合材料的形态结构和力学性能．结果表明：i-PP-g-MAH对i-PP／CaSO4复合物的缺口抗冲强度、弯曲强度和拉伸强度均有增强作用；i-PP-g-MAH对硫酸钙晶须填充的i-PP／CaSO4复合物表观粘度几乎没有影响．SEM观察发现i-PP-g-MAH对硫酸钙晶须填充的i-PP／CaSO4复合物相界面有明显的改善．     

纤维表面处理对RTM工艺及其制品的影响

采用RTM工艺分别对2种玻璃纤维试样进行充模实验,一种玻璃纤维试样未经任何处理,另一种试样用丙酮浸泡24 h后去除其表面上胶剂。通过实验研究这2种纤维试样的可浸润性和渗透率,同时分别对充模实验所得的2种纤维增强复合材料样板进行拉伸性能测试,最后用DMA和SEM对这2种样板的界面性能进行分析研究。得出结论:玻璃纤维经丙酮表面处理后,其可燃物含量降低,可浸润性提高,渗透率增大,其制得的复合材料样板空隙率减小,但树脂与纤维的界面结合强度下降,样板拉伸强度降低。     

结构加固用CFRP片材拉伸性能的试验研究

采用几种环氧树脂和碳纤维布制成碳纤维增强复合材料片材，通过测试拉伸强度、弹性模量、伸长率，研究探讨了影响CFRP片材拉伸强度的几种因素。研究结果表明，纤维、树脂本身的力学性能指标、含胶量、浸润性能等均对CFRP片材的拉伸性能有很大影响。     

聚吡咯层对聚酯/环氧树脂界面粘结性能的影响

采用吡咯化学沉积聚合方法对聚酯(PET)纤维进行表面改性,研究聚合工艺条件对纤维与环氧树脂界面剪切强度的影响.分别用SEM、共聚焦显微镜、DMA及单纤维拔出实验等测试手段对改性前后纤维的表面形貌、粗糙度、聚吡咯(PPy)与基体纤维大分子作用力及复合材料的界面剪切强度(IFSS)进行研究.结果表明:吡咯化学沉积聚合改性是一种有效提高纤维与树脂界面粘结性能的方法.此外,可进一步通过聚合改性工艺条件控制聚吡咯层的形貌及聚吡咯与基体纤维大分子的作用力,从而调控纤维与树脂界面剪切强度,吡咯气相化学沉积后再液相沉积,增强复合材料界面剪切强度比原纤维的提高了127.98%.     

纳米碳纤维复合材料的制备及其力学性能研究

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,制备了纳米碳纤维/环氧树脂复合材料。红外光谱测试结果表明,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。处理后纳米碳纤维的分散性有了明显的改善和提高。SEM和复合材料拉伸性能测试结果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,提高复合材料的拉伸性能。当酸化处理纳米碳纤维的质量分数为0.1%时,复合材料的拉伸强度达到最大值,是纯树脂的1.8倍,是同含量未处理纳米碳纤维材料的1.6倍。     

表面处理碳纤维对增强尼龙复合材料性能影响

采用空气氧化法对碳纤维进行表面处理 ,以注塑成型法制备碳纤维增强尼龙 1 0 1 0复合材料 .研究发现表面处理碳纤维可明显提高增强尼龙复合材料的拉伸强度和摩擦学性能 ,其中摩擦系数较未处理碳纤维增强降低了 3 0 %～ 5 0 % ,而耐磨性提高了 2～ 3倍 .用扫描电镜对拉伸断口和磨损表面形貌分析发现 ,表面处理可显著改善碳纤维和尼龙基体间的界面结合性能 .最后对影响表面处理碳纤维增强复合材料性能的作用机理进行了初步分析     

玻璃纤维增强环氧树脂基复合材料的低温性能研究

对S玻璃纤维和E玻璃纤维增强环氧树脂基复合材料的常温和低温力学性能进行实验,结果表明：玻纤／环氧树脂单向复合材料力学性能随着纤维含量增加而增强,当纤维体积含量为50％时,复合材料具有较好的综合力学性能,且复合材料的强度随着温度的降低呈增加趋势。当温度降到76K时材料的强度达到最高值,S玻纤／环氧复合材料的拉伸强度最高值可达2．1GPa;E玻纤／环氧复合材料的最大拉伸强度也达到1．4GPa。其原因是由于低温下玻璃纤维的横向收缩比树脂基体小,界面摩擦力得到增强,从而获得高的界面粘接强度。     

The Mechanical Properties of Polyurethane Elastomer Reinforced and Toughened By CaSO4—Whisker

CaSO4 whisker reinforcing and toughening mechanisms for polyurethane elastomer were studied.The effects of dispersity of CaSO4 whisker and interfacial bonding state on reinforcement and toughness were discussed.The microanalyses showed that CaSO4 whisker reinforcing mechanism for polyurethane elastomer mainly was load transferring and its toughening mechanism involved crack deflection and whisker pullout.The results indicated that composites with 5%-10% CaSO4 whisker exhibited the best mechancal properties,Good bonding in terface was formed between whisker and matrix after the surface of CaSO4 whisker was treated by silane coupling agent.The fairly improved strength and toughness are attributed to the better interfacial bonding state.     

Stress singularity near the end of a cylindrical interface and the linear elasticity of push-in tests

Ｉｎｔｅｒｆａｃｅｐｌａｙｓａｖｅｒｙｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｍｅｃｈａｎｉｃａｌｐｒｏｐｅｒｔｉｅｓｏｆｆｉｂｅｒｒｅｉｎｆｏｒｃｅｄｃｏｍｐｏｓｉｔｅｓ.Ｔｈｅｒｅｓｅａｒｃｈｅｓｓｈｏｗｔｈａｔｉｍｐｒｏｖｅｍｅｎｔｓｏｆｉｎｔｅｒｆａｃｉａｌｂｏｎｄｉｎｇｉｎｃｏｍｐｏｓｉｔｅｓｃａｎｅｎｈａｎｃｅｃｏｍｐｏｓｉｔｅｓｔｒｅｎｇｔｈｂｕｔｍａｋｅｔｈｅｔｏｕｇｈｎｅｓｓｄｅｃｒｅａｓｅ.Ｔｈｅｒｅｆｏｒｅ,ｔｈｅｏｐｔｉｍｉｚａｔｉｏｎｏｆｃｏｍｐｏｓｉｔｅｉｎｔｅｒｆａｃｅｉｓｒｅ…     

The Mechanical Properties of Polyurethane Elastomer Reinforced and Toughened By CaSO_4-Whisker

1　ＩｎｔｒｏｄｕｃｔｉｏｎＷｈｉｓｋｅｒｓａｒｅｔｈｅｕｌｔｉｍａｔｅ ｓｔｒｅｎｇｔｈｓｈｏｒｔ ｆｉｂｅｒｒｅｉｎ ｆｏｒｃｅｒｂｅｃａｕｓｅｔｈｅｙａｒｅｓｍａｌｌ (ｆｒｏｍｓｕｂｍｉｃｒｏｎｔｏｓｅｖｅｒａｌｍｉｃｒｏｎｓｉｎｄｉａｍｅｔｅｒ)ｓｉｎｇｌｅｃｒｙｓｔａｌｆｉｂｅｒｓｗｉｔｈａｈｉｇｈｄｅ ｇｒｅｅｏｆｃｒｙｓｔａｌｌｉｎｅｐｅｒｆｅｃｔｉｏｎ .Ｔｈｅｓｍａｌｌｅｒｔｈｅｗｈｉｓｋｅｒｉｓ ,ｔｈｅｇｒｅａｔｅｒｔｈｅｐｅｒｆｅｃｔｉｏｎｗｉｌｌｂｅ .Ｔｈｉｓｐｅｒｆｅｃｔｉｏｎ…     

Effect of fiber volume fraction on longitudinal tensile properties of SiC<Subscript>f</Subscript>/Ti-6Al-4V composites

The longitudinal tensile properties of SiC_f/Ti-6Al-4V composites with different fiber volume fractions were simulated by the Monte Carlo 2-D finite element model. The random distribution of fiber strength was expressed by the two-parameter Weibull function. Meanwhile, contact elements and birth-death elements were used to describe the interfacial sliding process after debonding and fiber breakage (or matrix cracking) respectively, which was realized by subroutine complied in ANSYS-APDL (ANSYS Parametric Design Language). The experimental results show that the yield stress and ultimate tensile strength of SiC_f/Ti-6Al-4V composites increase with increasing fiber volume fraction, while the corresponding strain of them is just on the contrary. In addition, almost the same failure mode is obtained in SiC_f/Ti-6Al-4V composites with various fiber volume fractions when the interfacial shear strength is fixed. Finally, the tensile strength predicted by finite element analysis is compared with that predicted by Global load-sharing model, Local load-sharing model and conventional rule of mixtures, thus drawing the conclusion that Local load-sharing model is very perfect for the prediction of the ultimate tensile strength.     

Effect of Fiber Volume Fraction on Longitudinal Tensile Properties of SiC_f/Ti-6Al-4V Composites

The longitudinal tensile properties of SiC_f/Ti-6Al-4V composites with different fiber volume fractions were simulated by the Monte Carlo 2-D finite element model. The random distribution of fiber strength was expressed by the two-parameter Weibull function. Meanwhile, contact elements and birth-death elements were used to describe the interfacial sliding process after debonding and fiber breakage(or matrix cracking) respectively, which was realized by subroutine complied in ANSYS-APDL(ANSYS Parametric Design Language). The experimental results show that the yield stress and ultimate tensile strength of SiC_f/Ti-6Al-4V composites increase with increasing fiber volume fraction, while the corresponding strain of them is just on the contrary. In addition, almost the same failure mode is obtained in SiC_f/Ti-6Al-4V composites with various fiber volume fractions when the interfacial shear strength is fixed. Finally, the tensile strength predicted by finite element analysis is compared with that predicted by Global load-sharing model, Local load-sharing model and conventional rule of mixtures, thus drawing the conclusion that Local load-sharing model is very perfect for the prediction of the ultimate tensile strength.     

最大界面剪切应力的估算与芳纶复合材料界面粘结的表征

研究以估算的最大界面剪切应力，表征芳纶Ｋｅｖｌａｒ４９复合材料的界面粘结。依据Ｇｒｅｓｚｃｚｕｋ模型和单纤维拔出实验数据估算最大界面剪切应力，研究纤维表面处理和基体改性对界面粘结的影响。选用不同活性基团表面的芳纶Ｋｅｖｌａｒ４９和两种耐高温树脂基体组成强粘结界面体系的研究结果表明，实验数据与理论曲线拟合很好。     

Tensile properties of an aluminum matrix composite reinforced by SnO<Subscript>2</Subscript>-coated Al<Subscript>18</Subscript>B<Subscript>4</Subscript>O<Subscript>33</Subscript> whisker

Al18B4O33 whisker was coated by SnO2 particles using a chemical precipitation method, and an aluminum matrix composite reinforced by the coated whisker was fabricated by squeeze casting technique. It is found that the SnO2 coating can react with aluminum matrix during squeeze casting process, and Sn particles are induced near the interface between Al18B4O33 whisker and matrix. The tensile test at room temperature indicated that the tensile strength of Al18B4O33 whisker reinforced aluminum matrix composite can be enhanced by suitable content of SnO2 coating. The composites with various whisker coating contents exhibit maximum tensile plasticity at about 300 ℃, and the composite with a suitable whisker coating content could enhance its tensile plasticity evidently, which suggest that an Al18B4O33 whisker-Al composite with both high strength at room temperature and high formability at elevated temperature can be designed.     

Effects of Matrix on Tensile Strength of SiCw/Al Composites

ＥｆｆｅｃｔｓｏｆＭａｔｒｉｘｏｎＴｅｎｓｉｌｅＳｔｒｅｎｇｔｈｏｆＳｉＣｗ／ＡｌＣｏｍｐｏｓｉｔｅｓ￥（耿林）（王德尊）（姚忠凯）ＧＥＮＧＬｉｎ；ＷＡＮＧＤｅｚｕｎ；ＹＡＯＺｈｏｎｇｋａｉ（Ｄｅｔｐ．ｏｆＭａｔｅｒｉａｌＳｃｉｅｎｃｅａｎｄＥｎｇｉ...     

Mechanical Properties of Phenolic-Resin Composites Reinforced with CF/BF Interlayer Hybrid Fibers

Phenolic-resin composites reinforced with carbon fiber (CF) and basalt fiber (BF) interlayer hybrid fibers plain fabric were fabricated. The tensile strength, compressive strength and interlaminar shear strength of the prepared composites were studied. The results indicated that hybrid fibers reinforced composites possessed the advantages of both CF and BF. When resin content was 35% by volume fraction, the comprehensive mechanical performance of BF/CF reinforced phenolic resin composites reached the optimal values with the warp and weft direction tensile strength, compressive strength and interlayer shear strength being 252 MPa and 487 MPa, 105 MPa and 129 MPa, 21 MPa and 20 MPa, respectively. The scanning electron microscope (SEM) observations showed that the BF/CF hybrid fibers reinforced composites had better interfacial adhesion.     

玻璃纤维增强环氧树脂单向复合材料力学性能分析

采用连续玻璃纤维与环氧树脂相复合,通过金属模压成型工艺,制备出单向玻璃纤维／环氧树脂复合材料。通过三点弯曲实验论证单向纤维对树脂基体的增强作用,从而研究不同纤维含量下复合材料的弹性模量、纵向拉伸强度、纵向压缩强度的变化趋势。结果表明：随着纤维含量的增加,复合材料的力学性能均增强,当纤维体积含量为50％时,其各项性能均较好,弹性模量为40GPa,纵向拉伸强度为1200MPa,纵向压缩模量为700MPa。此外,对复合材料的其他常用力学性能参数进行检测。