聚苯硫醚/钕铁硼复合材料力学性能与电磁性能

采用熔融共混的方法制备了聚苯硫醚(PPS)/钕铁硼(NdxFe94-xB6)复合材料,分析了复合材料的形态、力学性能及电磁性能。结果表明,均匀分散的钕铁硼粒子与PPS基体界面结合紧密;与纯PPS相比,钕铁硼添加量为50%时,复合材料的拉伸强度、弯曲强度和冲击强度分别提高了49%、44%和700%;但过多的钕铁硼填充量反而不利于复合材料力学性能的提升;复合材料的介电常数和磁导率都随其含量增加而增大,在高含量下,介电常数虚部随频率增加明显增大。通过对复合材料反射衰减计算,匹配厚度d=2 mm时,复合材料在高频段出现明显的吸收峰,特别是含量为50%时,吸收峰达到-18.3 dB,对应的频率为16.6 GHz。     

碳纤维/玻璃纤维复合纤维毡的介电和吸波性能

考察了碳纤维/玻璃纤维复合并浇注硅溶胶制成的纤维毡的介电和吸波性能。结果表明:碳纤维的分散对复合材料的介电性能有很大影响。复合材料的介电常数随着碳纤维含量的增加而增加,随频率的增加而降低,具有明显的频响效应。复合材料具有明显的双峰吸收性能,且最高吸收峰随着厚度的增加向低频移动。当w(碳纤维)=1%,复合材料厚度为6、7、8 mm时,反射率小于-10 dB的频段分别为4.2~10.5、3.9~9.3、3.8~7.7 GHz。     

聚苯硫醚/纳米Si3N4复合材料的制备及性能研究

表面改性处理的纳米Si3N4粉体与聚苯硫醚（PPS）熔融共混挤出制成PPS/纳米Si3N4复合材料,通过拉伸、冲击实验及动态力学性能测试考察了纳米粉体加入量对复合体系各项性能的影响。结果表明,纳米Si3N4填充PPS基复合材料的力学性能明显优于纯PPS。随粉体添加量的增加,复合材料的拉伸强度增大,当添加量为0.8 %时,拉伸强度提高了22 %。随粉体添加量的增加,复合体系冲击强度增大,当粉体添加量为1.2 %时,冲击强度和缺口冲击强度出现最大值,分别比纯PPS增加了33 %和41 %。动态力学性能测试表明,随粉体添加量的增加,PPS分子链段松弛所需能量增加,松弛过程增长,体系储能模量降低,损耗模量增加。     

多壁碳纳米管/聚苯硫醚管复合材料的电磁性能

采用熔融共混法制备了多壁碳纳米管/聚苯硫醚复合材料,研究了在0.5~18 GHz频段,不同碳纳米管含量对复合材料电磁性能的影响。结果表明,介电常数实部与虚部随着碳纳米管含量的增加而增大, 介电常数实部在测量范围内随频率的增加而减小, 具有明显的频响特性;复合材料的磁导率随多壁碳纳米管含量的增加变化不明显, 呈弱磁性;通过对复合材料反射衰减的计算发现,当吸收层匹配厚度为2 mm 时,复合材料在0.5~18 GHz频段具有较好的微波吸收性能;当碳纳米管含量为7 %（质量分数,下同）时,反射衰减最大达- 31.5 dB ,反射衰减小于- 10 dB的频宽为2.2 GHz。     

硅微粉改性PI/PPS/GF复合材料的制备及性能

采用双螺杆挤出机挤出工艺,制备了硅微粉改性聚酰亚胺(PI)/聚苯硫醚(PPS)/玻璃纤维(GF)复合材料。研究了PPS用量和硅微粉用量对PI/PPS/GF复合材料力学性能、动态力学性能、线膨胀系数和热性能的影响。复合材料拉伸强度、弯曲强度、悬臂梁无缺口冲击强度和初始储能模量随PPS用量增加而逐渐降低,线膨胀系数和熔体质量流动速率随之增加;材料力学性能随硅微粉用量增加先增加后减小,线膨胀系数和熔体质量流动速率随之增加而明显降低。差示扫描量热仪(DSC)数据分析表明,PPS材料的加入使复合材料在230~240℃出现了结晶峰,硅微粉使初始结晶温度变高;复合材料的热稳定性能随着熔融硅微粉用量增加而增加。     

硫酸钙晶须增强聚苯硫醚/玻璃纤维复合材料的性能研究

通过熔融共混的方法,制备了硫酸钙晶须增强聚苯硫醚(PPS)/玻璃纤维(GF)复合材料。研究了晶须用量对PPS/GF/晶须复合材料力学性能和热性能的影响。结果表明:晶须用量为10份时,复合材料的拉伸强度、弯曲强度、悬臂梁缺口冲击强度和负载变形温度分别为157 MPa、273 MPa、8.5 k J/m2和151℃。差示扫描量热仪(DSC)和热失重(TGA)分析结果表明:当晶须用量较少时,结晶峰移向高温方向;晶须用量大于20份时,结晶峰略向低温方向偏移,复合材料的分解温度随晶须用量的增加而逐渐升高。     

环氧树脂基介电复合材料的制备和性能研究

以环氧树脂(EP)为基体树脂、经硅烷偶联剂改性后的压电陶瓷钛酸钡(BaTiO3)为增强填料,采用浇铸法制备了有机/无机介电复合材料。研究了填料用量对复合材料介电性能、力学性能和热性能的影响。实验结果表明,BaTiO3能显著提高材料的介电常数,当w(BaTiO3)=60%时,复合材料的介电常数为23.6,比纯EP的介电常数(4.0)提高了近6倍,而且复合材料的介电常数受频率影响较小,具有较好的频率稳定性;随着BaTiO3含量的增加,材料的弯曲强度和冲击强度都呈先增后减的趋势,最大弯曲强度和冲击强度分别为123.8 MPa和26.3 kJ/m2;材料的热稳定性研究表明,材料的起始热分解温度随着BaTiO3含量的增加而提高,材料的耐热性能得到改善。     

玄武岩纤维增强聚苯硫醚的性能研究

采用熔融共混的方法制备了玄武岩纤维(BF)增强聚苯硫醚(PPS)复合材料。考察了BF用量对PPS/BF复合材料力学性能、热性能和结晶性能的影响,以及硅烷偶联剂和填料种类对PPS/BF复合材料力学性能的影响。结果表明:复合材料的拉伸强度、弯曲强度、冲击强度、负荷变形温度和分解温度均随BF用量的增加而提高;硅烷偶联剂KH560的加入可以改善复合材料的力学性能。在PPS/BF体系中添加玻璃纤维可以进一步提高材料的力学强度;在PPS/BF体系中添加甲基丙烯酸缩水甘油酯接枝乙烯-辛烯共聚物(POE-g-GMA)可以提高复合材料的无缺口冲击强度。通过差示扫描量热(DSC)测试发现,BF具有异相成核作用,可以促进树脂结晶并提高结晶速率。     

两种不同基体木塑复合材料的制备及性能研究

以稻糠代替木粉,分别制备了高密度聚乙烯(HDPE)基体和聚甲醛(POM)基体木塑复合材料。结果表明稻糠含量小于50%时,这两种木塑复合材料均具有良好的加工流动性;稻糠含量从0增加到50%,拉伸强度和冲击强度下降,热变形温度提高;稻糠含量40%时,木塑复合材料韧性相对于单纯树脂下降最小;稻糠含量在40%时,耐热性能改善效果最为明显。综合各因素对木塑复合材料性能的影响,稻糠填充量选在40%较合适。POM基体木塑复合材料在拉伸性能、弯曲性能和耐热性能方面优于HDPE基体木塑复合材料,但在无缺口冲击性能方面HDPE基体木塑复合材料优于POM基体木塑复合材料。     

高强耐磨PPS/PTW/GF复合材料的制备与性能研究

在聚苯硫醚(PPS)中加入活化处理过的钛酸钾晶须(PTW)和玻璃纤维(GF),熔融共混挤出制得PPS/PTW/GF复合材料。探究了复合材料力学性能和摩擦性能随钛酸钾晶须添加量的变化以及复合材料力学性能随玻璃纤维添加量的变化关系。结果显示,添加适量的钛酸钾晶须能改善材料的力学性能和摩擦性能,降低了磨耗。玻璃纤维的加入能较大幅度提高材料的力学性能。当PPS/PTW/GF质量比为48/12/40时,可制得综合性能优良的高强耐磨复合材料,其冲击强度10.1 kJ/m2、拉伸强度157 MPa、弯曲强度208 MPa、摩擦因数为0.14、磨耗量28 mg。     

基于双转子连续混炼挤出机的PPS/CF复合材料制备及性能研究

采用双转子连续混炼挤出机并通过熔融共混法制备了碳纤维(CF)增强聚苯硫醚(PPS)复合材料,并对其微观形貌、动态力学性能、力学性能和导电性能进行了研究,且对相关的影响因素进行了分析。结果表明,适当降低挤出机转子转速、提高CF含量可以改善PPS/CF复合材料的力学性能和导电性能;当转子转速为200r/min时,采用含量为20 % (质量分数,下同)的CF制得的PPS/CF复合材料的冲击强度达到49.94 J/m,体积电阻率达到60.65 Ω·cm,均优于纯PPS。     

Effects of fiber contents on the mechanical and microwave absorbent properties of carbon fiber felt reinforced geopolymer composites

In this paper, phosphate-based geopolymer composites are studied and the effects of different carbon fiber felt contents (from 20?vol% to 40?vol%) on the phase composition, microstructure, mechanical properties and microwave absorbent properties from 2?GHz to 18?GHz frequency band of the composites were systematically investigated. The results indicate that with the increase in carbon fiber felt contents, flexural strength and Young's modulus of the composites gradually increased. The fracture mode of the composite changed from brittle failure to ductile failure with the presence of carbon fiber felt. It was mainly due to the micropore deformation as well as fibers pulling-out and the crack deflection, which consumed most fracture energy. However, microwave absorbent performance tended to increase at first and then decreased as the carbon fiber felt content ramping up. When the content of carbon fiber felt in the composite was 26.7?vol%, the composite showed the best microwave absorbent performance and the reflection loss reached to ??59.3?dB. It is mainly attributed to the Debye polarization of the carbon fibers and the interface polarization between fibers and the matrix.     

Effect of Filler Content on the Dielectric Properties of PTFE/ZnAl2O4–TiO2 Composites

ZnAl₂O₄–TiO₂ (ZAT)/polytetrafluoroethylene (PTFE) composites were prepared by powder processing method. The structure and microstructure of the composites were analyzed using X-ray diffraction and scanning electron microscopic techniques. The effect of different volume fraction of ZAT (0–0.6) on the dielectric properties of the composites was investigated at 1 MHz and at the microwave frequency of 7 GHz. The dielectric properties (relative permittivity and dielectric loss) were found to increase with the ZAT content. The samples with 60 vol.% of ZAT filler showed a relative permittivity of 3.9 and dielectric loss of 0.009, respectively, at 7 GHz. The variation of relative permittivity and dielectric loss showed only a very small variation with temperature in the range 25°–70°C for various ZAT/PTFE composites. The relative permittivity obtained experimentally were compared with that of the theoretical values predicted using modified Lichtenecker, Jayasundere—Smith, and Series mixing formulae. They were found to agree well with the predicted values for low filler content.     

石墨-石膏基吸波复合材料的制备与性能

采用弓形反射率测试系统等现代测试手段,通过测试复合材料在2～18GHz频率范围内的吸波性能和力学性能,研究了石墨掺量、试样厚度对石膏基吸波复合材料吸波性能的影响以及石墨掺量对力学性能的影响.研究表明,石墨-石膏基材料在2～18GHz具有较好的吸波性能,厚度一定,当石墨掺量为25wt％时试样吸波性能最佳;增大厚度有利于提高试样的吸波性能,掺量20wt％,厚度为20mm的试样小于-5dB的连续带宽高达15.68GHz;复合材料的力学性能随石墨掺量的增加而逐渐减小,掺量为40wt％时,其28d的抗压和抗折强度与空白试样相比分别下降了67.9％和76％.     

Preparation of Soft Magnetic FeNip/PP Nanocomposites by Multi-Step Dispersion Process

FeNi nanopowders are dispersed into the polypropylene to form FeNi_p/PP nanocomposites by a combination method of high-temperature solution blending process and two-step blending process. The excellent dispersion of FeNi nanoparticles led to significant improvements in mechanical and soft magnetic properties. When the powders content is in the range of 1?～?3?wt.%, the strength of PP resin reached its peak strength which is 20?～?27% higher than that of the pure resin. The composites have wave-absorbing properties in the frequency range of 1?～?2?GHz. It was concluded that the multi-step dispersion process is a simple and versatile way for the fabrication of polyolefin-based nanocomposites with superior functionalities.     

玻璃纤维增强PA66复合材料作为高压开关设备绝缘件材料的可行性分析

选取不同短切玻璃纤维（SGF）含量的聚酰胺66（PA66）/SGF复合材料,研究对比PA66/SGF复合材料与热固性环氧树脂基绝缘材料的物理性能、力学性能和绝缘性能。结果表明,随着SGF含量的增加,PA66/SGF复合材料的密度增大,但均低于热固性环氧树脂基绝缘材料标准;弯曲强度、拉伸强度和冲击强度增大,当SGF含量达到20 %以上时,复合材料的综合力学性能达到热固性环氧树脂基绝缘材料标准;击穿强度和耐电弧时间增加,优于热固性环氧树脂基绝缘材料标准。因此,PA66/SGF复合材料作为高压开关设备绝缘件材料是可行的,但实际应用还需进一步的工程应用研究。     

玻纤增强PPS/MgO绝缘导热复合材料的研究

通过双螺杆挤出机将聚苯硫醚(PPS)与MgO混合挤出,同时添加玻璃纤维(GF)挤出造粒制备了玻纤增强PPS/MgO绝缘导热复合材料。研究了材料的导热性能与MgO含量的关系。研究发现,材料的热导率随MgO含量的增加而增大;GF替代部分MgO后,导热性能有所降低,但拉伸强度和冲击强度等力学性能得到提高;偶联剂用量在0.5%时可提高PPS/MgO绝缘导热复合材料的热导率。     

Electrical conductivity,dielectric and microwave absorption properties of graphene nanosheets/magnesia composites

Herein, a novel microwave absorbing material with Graphene nanosheets (GNSs) as microwave absorbing filler and magnesia (MgO) as matrix were prepared by hot-pressing sintering. The composites were highly dense with a homogeneous distribution of GNSs. Electrical conductivity, dielectric and microwave absorption properties in X-band were investigated. The results revealed that the electrical conductivity of the GNSs/MgO composites showed a typical percolation-type behavior with a percolation threshold of 3.34 vol%. With GNSs content increased to 3 vol%, the real permittivity, imaginary permittivity and dielectric loss tangent of the composites increased from ～9, ～0 and ～0 to 26–43, 23–28 and 0.55–0.96, respectively. By adjusting the GNSs content, thickness and frequency, the 2.5 vol% GNSs/MgO composite shows the minimum reflection loss of ?36.5 dB at 10.7 GHz and the reflection loss below ?10 dB (90% absorption) ranges from 9.4 to 11.4 GHz with 1.5 mm thickness, exhibiting excellent microwave absorption properties.     

Study on mechanical properties of powder impregnated glass fiber reinforced poly(phenylene sulphide) by injection molding at various temperatures

The prepreg of continuous glass fiber reinforced poly(phenylene sulphide) (PPS) was prepared using the powder impregnation technique and cut into the pellets, in which the length of glass fibers was the same as the pellets. After injection molding, the mechanical properties were tested and the effects of the pellet length, fiber content, and thermal treatment on the mechanical properties at different temperatures were studied. It is found that the tensile strength and flexural strength of 6‐mm pellet sample are slightly higher than that of 3‐ and 12‐mm pellet samples. The tensile strength, flexural strength, and modulus decrease significantly with increasing the temperature. The notched Izod impact strength at 85ºC is higher than both at 25ºC and 205ºC. At 205ºC, the glass fiber reinforced PPS composites can still keep better mechanical properties. When the fiber content ranges from 0 to 50%, the mechanical properties increase with increasing the fiber contents at different temperatures, except the notched Izod impact strength do not further increase at 145 and 205ºC with raising the fiber content from 40 to 50%. Thermal treatment could improve the mechanical properties of the composites at higher serving temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

端羧基修饰单宁酸/没食子酸环氧树脂复合材料的制备与性能研究

通过A₂+B₃一步法及缩聚反应分别制备生物质超支化聚合物 （CTMTA）和没食子酸环氧树脂（GAER）,采用熔融共混法制备了没食子酸环氧树脂（GAER）/甲基四氢苯酐（MTHPA）/2?甲基咪唑（2?MI）/ 超支化聚合物 （CTMTA）复合材料。利用傅里叶变换红外光谱仪（FTIR）、核磁共振仪（¹H?NMR）、差示扫描量热仪（DSC）、扫描电子显微镜（SEM）、力学性能和吸水率等试验,研究了CTMTA 含量对GAER/MTHPA/2?MI复合体系性能的影响。结果表明,CTMTA的加入能提高复合体系的力学性能和吸水率,降低复合体系的固化温度。当CTMTA含量为1.5 %（质量分数,下同）时,GAER/MTHPA/2?MI/CTMTA复合体系的力学性能和吸水率最佳,拉伸强度、断裂伸长率、冲击强度和吸水率分别比GAER/MTHPA/2?MI体系提高了33 %、37 %、47.6 %和45.5 %。GAER/MTHPA/2?MI/CTMTA复合体系的最佳固化工艺参数为110 ℃/20 min。