空心石英玻璃纤维增强氰酸酯基低介电复合材料的制备及性能分析

研究了空心石英纤维增强新型改性氰酸酯树脂基复合材料的力学性能、热物理性能和介电性能,结果表明,空心石英纤维增强氰酸酯复合材料具有较好的力学性能和优异的介电性能。空心石英纤维增强新型改性氰酸酯树脂基复合材料的介电常数低且具有较好的频率稳定性,适合作为宽频高透波材料。     

聚酰亚胺纤维增强树脂基复合材料的研究

以聚酰亚胺纤维为增强体,环氧树脂、双马来酰亚胺树脂、氰酸酯和聚酰亚胺树脂为基体,通过模压成型法制备了4种聚酰亚胺纤维增强的树脂基复合材料。研究了4种基体树脂低聚物的固化行为和流变性能,并表征了4种相应树脂基复合材料的热学、力学、介电性能以及纤维与树脂之间的界面性能。结果表明:4种基体树脂低聚物最低黏度都低于15Pa·s,显示了良好的成型工艺性,环氧树脂基复合材料的力学性能最好,弯曲强度、弯曲模量和层间剪切强度分别达到716MPa、54.9GPa和56.5MPa;聚酰亚胺树脂基复合材料的耐热等级最高,玻璃化转变温度大于300℃;氰酸酯树脂基复合材料的介电性能最优,介电常数在低频段低于3.3。     

玻璃纤维布增强聚四氟乙烯复合材料的制备及性能研究

制备了玻璃纤维布增强聚四氟乙烯复合材料;分析了偶联剂对复合材料性能的影响;讨论了树脂含量对材料介电性能和拉伸强度的影响;探讨了烧结工艺对复合材料拉伸强度影响;对复合材料介电性能理论值与试验值进行了对比分析.     

有机硅改性磷酸铬铝透波材料

对有机硅改性磷酸铬铝基体的制备及其复合材料的制备进行了研究。通过添加有机硅树脂对磷酸铬铝进行改型,改性基体的剪切拉伸性能从1.2MPa提高到了3.0MPa以上,其介电常数从4.0左右降低到了3.6左右;其复合材料弯曲强度从80MPa提高到了100MPa以上,吸水率降低了71%。     

短切石英纤维/聚酰亚胺复合材料的制备与性能

采用湿法混合工艺制备了短切石英纤维增强的PMR 型聚酰亚胺复合材料模塑粉, 使用热模压一次成型技术制备了聚酰亚胺树脂基复合材料, 对复合材料的性能进行了系统研究。研究结果表明: 短切石英纤维增强的复合材料具有优异的热性能和良好的力学性能, 纤维含量对复合材料玻璃化转变温度和热失重温度影响不大,对材料的力学性能影响显著。复合材料具有优异的介电性能, 在1 kHz～18 GHz 宽频范围内具有稳定的介电常数和介电损耗。      

烧结温度对莫来石增强磷酸铬铝材料的制备与性能影响

以固相烧结莫来石为增强体,制备了莫来石增强磷酸铬铝基复合材料。研究了烧结温度对复合材料的微观结构和性能的影响。采用SEM、XRD、EDS等检测手段对复合材料的物相结构及断面的微观形貌进行分析,使用万能试验机测试其材料的抗折强度,并使用矢量网络分析仪分析材料的介电性能。结果表明,随着烧结温度的升高,复合材料中莫来石的晶粒依次增大,材料致密度、介电常数增加,抗弯强度增加,但过高的烧结温度下抗弯强度会降低。当烧结温度为1 500℃时,材料的抗弯强度为107 MPa,平均介电常数为3.57。     

石墨烯/SiO2杂化材料增强增韧环氧树脂基复合材料

采用原位接枝法制备得到三维结构的石墨烯/SiO2杂化材料,用透射电镜对杂化材料的表观形貌进行表征,同时对二氧化硅的粒径进行表征。利用环氧树脂固化工艺制备复合材料样条,将不同比例(0.1%、0.3%、0.5%)的杂化材料添加到树脂中制备树脂基复合材料,利用万能强力仪测试样条的拉伸性能,利用扫描电镜对样条的断截面进行扫描,研究不同比例的杂化材料对树脂增强增韧效果的影响,并得到最佳的添加比例。再以最佳添加比例将石墨烯、SiO2、杂化材料分别添加到树脂中制备树脂基复合材料,研究不同种类的填料对树脂基复合材料的增强增韧效果。结合拉伸测试结果和断截面扫描结果分析可以得到,杂化材料的添加量为0.3%时,对树脂基复合材料的增强增韧效果最佳;且杂化材料对树脂的增强增韧效果要明显优于单独添加石墨烯和二氧化硅。     

超高分子量聚乙烯纤维增强复合材料的性能研究

采用一种结构与超高分子量聚乙烯(UHMWPE)纤维相似、且对纤维表面具有良好浸润性的碳氢树脂(PCH)作基体,通过层压成型方法制得UHMWPE/PCH复合材料.研究了复合材料的力学性能、介电性能、吸湿性能及界面黏结性能.结果表明,UHMWPE/PCH复合材料介电性能优异、力学性能好、耐湿热性能较佳、界面黏结性能好,可用作高性能透微波复合材料.     

ZnO及填料对磷酸铬铝基复合材料性能的影响

以磷酸铬铝(ACP)为基体,高硅氧纤维布为增强材料,Cr2O3和Al2O3为填料,通过热压成型制得磷酸铬铝基复合材料。采用TG-DSC和XRD等探讨了磷酸铬铝基体的固化特性和耐热性能,并研究了复合填料、纳米填料及热压工艺对材料力学性能的影响。结果表明,ZnO可以降低磷酸铬铝的固化温度并促进其晶型转变;复合填料Cr2O3和Al2O3可以提高材料的耐热性,当Cr2O3和Al2O3之比为7∶3且纳米Cr2O3加入量为5%时,复合材料的力学性能最好,其拉伸强度为95.2MPa,弯曲强度为190.02MPa。     

湿热老化对玻璃纤维/环氧树脂复合材料性能的影响

为研究玻璃纤维(GF)/环氧树脂复合材料湿热老化机制, 首先, 利用称重法、动态热机械分析仪(DMA)、SEM和矢量网络介电分析仪研究了湿热老化对GF/环氧树脂608(EP608)复合材料性能的影响;然后, 分析了复合材料的吸湿率、力学性能、介电性能与老化时间的关系, 并对其老化机制进行了探讨。结果表明:随老化时间延长, GF/EP608复合材料的力学性能和介电性能均有不同程度的下降;湿热老化对GF/EP608复合材料吸湿率的影响符合Fickian扩散定律;树脂基体的塑化、水解和基体-纤维界面的破坏是造成GF/EP608复合材料力学性能和介电性能下降的主要因素。所得结论可为GF增强环氧树脂基复合材料的应用提供科学依据。      

Preparation and characterisation of PE films of carbon nanotube/polyaniline (PAN) composite mixture

ABSTRACT

Polyaniline (PAN) composites filled with nanotube were prepared by twin-screw extruder in order to study the influence of PE reinforcing effect on the mechanical behaviour of the nanotube/polyaniline (PAN) composites. The mechanical property tests of the composites with and without PE were performed. The tensile and flexural strength of nanotube/polyaniline (PAN) composites with polyethylene (PE) was improved. In conclusion, the addition of PE favoured the improvement of the higher interface strength and so had good effect on improving the tensile and flexural properties of the composites. The dielectric strength was slightly increased with the PE content increasing and then decreased gradually. The hybrid film with 2 wt.% of PE shows the dielectric strength of 199 MV/m, which is about 6% higher than that of nanotube/polyaniline (PAN) film (188 MV/m).     

拟薄水铝石改性环氧树脂复合材料的制备与性能

采用水热合成法制备拟薄水铝石(AlOOH)纳米棒,以3-氨基丙基三乙氧基硅烷(APTES)为表面改性剂,制得mAlOOH,以环氧树脂(Epoxy,EP)为基体,制备AlOOH/EP和mAlOOH/EP复合材料。研究AlOOH和mAlOOH的填充量对AlOOH/EP及mAlOOH/EP复合材料性能的影响。结果表明,mAlOOH明显提高了mAlOOH/EP复合材料的力学性能。mAlOOH的填充量为4wt%时,mAlOOH/EP复合材料的冲击强度和弯曲强度分别比聚合物基体分别提高了259%和44%;填充量不超过5wt%时,mAlOOH/EP的介电常数与介电损耗均略低于纯环氧树脂。当添加量为3wt%时,mAlOOH/EP具有最低的介电常数和介电损耗及最高的玻璃化转变温度(123℃)。      

Fabrication and testing of natural fibre composites: Vakka, sisal, bamboo and banana

A study has been carried out to investigate the tensile, flexural and dielectric properties of composites made by reinforcing vakka as a new natural fibre into a polyester resin matrix. The fibres extracted by retting and manual processes have been used to fabricate the composites. These composites are tested for tensile, flexural and dielectric properties and compared with those of established composites like sisal, bamboo and banana made under the same laboratory conditions. The composites are fabricated up to a maximum volume fraction of fibre of 0.37 in the case of tensile testing, and 0.39 for flexural and dielectric testing. It has been observed that the tensile properties increase with respect to volume fraction of fibre for vakka fibre composite and are also more than those of sisal and banana composites and comparable to those of bamboo composites. The flexural strength of vakka fibre composite is more than that of banana composite and is closer to sisal fibre composite with respect to the volume fraction of fibre, where as the flexural modulus is much higher than those of banana and sisal fibre composites and also very much closer to bamboo fibre composites. The dielectric strength of vakka fibre composite increases with increase in volume fraction of fibre in the composite unlike the case of sisal, bamboo and banana composites. The dielectric strength being a unique feature of vakka fibre composite, can be suggested for electrical insulation applications.     

Preparation and properties of unidirectional boron nitride fibre reinforced boron nitride matrix composites via precursor infiltration and pyrolysis route

The unidirectional boron nitride fibre reinforced boron nitride matrix (BN_f/BN) composites were prepared via the precursor infiltration and pyrolysis (PIP) route, and the structure, composition, mechanical and dielectric properties were studied. The composites have a high content and fine crystallinity of BN. The density is 1.60 g cm⁻³ with a low open porosity of 4.66%. The composites display good mechanical properties with the average flexural strength, elastic modulus and fracture toughness being 53.8 MPa, 20.8 GPa and 6.88 MPa m^1/2, respectively. Lots of long fibres pull-out from the fracture surface, suggesting a good fibre/matrix interface. As temperature increases, both of the flexural strength and elastic modulus exhibit a decreasing trend, with the lowest values being 36.2 MPa and 8.6 GPa at 1000 °C, respectively. The desirable residual ratios of the flexural strength and elastic modulus at 1000 °C are 67.3% and 41.3%, respectively. The composites have excellent dielectric properties, with the average dielectric constant and loss tangent being 3.07 and 0.0044 at 2-18 GHz, respectively.     

羟基磷灰石的含量对C_(f)/HA-CS复合材料力学性能的影响

以羟基磷灰石-壳聚糖(HA-CS)为基体,炭纤维为增强相,采用原位杂化的方法,制备了短切炭纤维增强HA-CS生物复合材料(C(f)/HA-CS)。重点研究了HA含量对复合材料结构及性能的影响。采用红外吸收光谱、X射线衍射、扫描电子显微镜和万能材料试验机分别对材料的结构及性能进行了测试和表征。结果表明,随着HA含量增加,复合材料的抗折强度和压缩强度都呈现先增加后下降的变化规律;当HA/CS=0.1时,复合材料抗折强度和压缩强度分别达到62.57 MPa和59.55 MPa的极大值。     

氧化硼-磷酸浸渍对中间相炭微球复合材料抗氧化及力学性能的影响

以原位缩聚法制备的中间相炭微球/碳纳米管(MCMB/CNTs)复合微球为原料, 通过添加氧化硼(B₂O₃)粉体和磷酸浸渍对该复合材料进行了基体和表面改性。采用扫描电子显微镜(SEM)、三点弯曲法、热重分析(TG)以及恒温氧化测试方法对复合材料的表面形貌、弯曲强度以及抗氧化性能进行了表征与测试。结果表明: 添加适量的B₂O₃可以有效提升复合材料的抗氧化性能和弯曲强度, B₂O₃含量超过2%时, 复合材料的弯曲强度逐渐下降。将含有2% B₂O₃的复合材料试样进行磷酸浸渍处理后, 试样的弯曲强度可达66 MPa, 初始氧化温度520℃, 经过500℃恒温氧化60 min后其氧化失重率仅为5%, 弯曲强度仍达到50.3 MPa。     

Preparation and properties of SiO2 matrix composites doped with AlN particles

SiO₂ matrix composites doped with AlN particles were prepared by hot-pressing process. Mechanical properties of SiO₂ matrix composites can be greatly improved by doping with AlN particles. Flexural strength and fracture toughness of 30 vol%AlN-SiO₂ composite sintered at 1400°C reached 200 MPa and 2.96 MPa·m^1/2. XRD analysis indicated that, up to 1400°C, no chemical reaction occurred between SiO₂ matrix and AlN particles suggesting an excellent chemical compatibility of SiO₂ matrix with AlN particles. The influences of hot-pressing temperature and the content of AlN particles on dielectric properties of SiO₂-AlN composites were studied. The temperature and frequency dependency of dielectric properties of SiO₂-AlN composites were also studied. Residual flexural strength of SiO₂-AlN composites decreased with increasing temperature difference. The critical temperature difference was estimated about 600°C.     

稀土改性对玄武岩纤维增强氰酸酯树脂复合材料性能的影响

采用自制稀土改性剂改性玄武岩纤维（La-BF）布增强双酚A型二氰酸酯（BADCy）制备了La-BF/BADCy复合材料。采用SEM和FTIR分析了改性对BF表面产生的影响,TG分析研究了改性对BF/BADCy复合材料热稳定性的影响,使用电子万能试验机研究改性对不同质量分数的BF/BADCy弯曲性能的影响,通过阻抗分析仪分析了改性对La-BF/BADCy复合材料介电性能的影响。结果表明,改性减少了BF的表面缺陷,并引入了结晶状凸起,有利于提高BF/BADCy复合材料的界面性能;通过改性提高了BF/BADCy复合材料的热稳定性,初始分解温度提高了145℃;当BF的质量分数为12wt%时,改性使BF/BADCy复合材料弯曲模量提高到4.19 GPa,弯曲强度达到110 MPa以上。在1 MHz~3 GHz范围内,La-BF/BADCy复合材料的介电常数稳定在1.9左右。因此稀土改性是一种能够有效提高BF/BADCy复合材料弯曲性能、热稳定性及介电性能的表面改性方法。      

Biocomposites from Musa textilis and polypropylene: Evaluation of flexural properties and impact strength

Abaca (Musa textilis)-reinforced polypropylene composites have been prepared and their flexural mechanical properties studied. Due to their characteristic properties, M. textilis has a great economic importance and its fibers are used for specialty papers. Due to its high price and despite possessing very distinctive mechanical properties, to date abaca fibers had not been tested in fiber-reinforced composites. Analysis of materials prepared showed that, in spite of reduced interface adhesion, flexural properties of the PP composites increased linearly with fiber content up to 50 wt.%. Addition of a maleated polypropylene coupling agent still enhanced the stress transfer from the matrix to the reinforcement fiber. As a result, composites with improved flexural properties were obtained. The mechanical properties of matrix and reinforcing fiber were evaluated and used for modelling both the flexural strength and modulus of its composites. In addition, the impact strength of materials was evaluated. Comparison with mechanical properties of composites reinforced with fiberglass points out the potentiality of abaca-reinforced polypropylene composites as suitable substitutes in applications with low impact strength demands.     

浸泡腐蚀对泡沫铝-环氧树脂复合材料弯曲性能的影响

制备了两种泡沫铝孔径的泡沫铝-环氧树脂复合材料。将试件分别浸泡于蒸馏水和海水中,得出了其吸湿率与浸泡时间的关系曲线。通过三点弯曲实验研究了浸泡腐蚀对复合材料弯曲强度和弯曲刚度等力学性能的影响。研究结果表明:泡沫铝-环氧树脂复合材料的吸湿率随浸泡时间的延长而逐渐增大,且试件在海水中浸泡的吸湿率大于在蒸馏水中的吸湿率。浸泡腐蚀大幅度地降低了泡沫铝-环氧树脂复合材料的弯曲力学性能。添加偶联剂的试件的弯曲强度和弯曲刚度均比无偶联剂试件的值更大,特别是对于泡沫铝孔径为2mm的复合材料试件,添加偶联剂使得其弯曲强度和弯曲刚度分别提高了51.7%和65.4%。另外,1mm孔径泡沫铝复合材料试件的弯曲强度和弯曲刚度均比2mm孔径泡沫铝复合材料试件的值更大。