舰船用新型耐高温阻燃结构材料--聚邻苯二甲腈复合材料

综述了舰船用新型耐高温阻燃结构材料-聚邻苯二甲腈复合材料优异的加工性能，耐高温性能，力学性能，阻燃性能以及低的烟密度等性能，并与PMR-15（高温型聚酰亚胺），普通和高性能环氧树脂进行了比较。指出聚邻苯二甲腈复合材料是目前唯一的在没有表面保护的情况下全面满足美国军用标准MIL-STD-2031要求的聚合物复合材料，聚邻苯二甲腈树脂的玻璃化转变温度高达450℃，在100kW/m^2热流下，玻璃纤维，碳纤维增强聚邻苯二甲腈的点燃时间和热释率分别为60s,106kW/m^2和75s,118kW/m^2。在潜艇和水面舰艇上具有广阔的应用前景。     

聚酰亚胺颗粒层间增韧碳纤维/邻苯二甲腈树脂复合材料

邻苯二甲腈树脂是一种新型的高性能热固性树脂,具有优良的力学性能和耐高温性能,而邻苯二甲腈树脂本身的脆性限制了其用作结构材料方面的应用。本文采用热塑性聚酰亚胺(PI)颗粒对邻苯二甲腈树脂复合材料进行层间增韧改性,研究改性前后复合材料的耐热性能和力学性能。研究发现,使用PI对邻苯二甲腈复合材料进行改性时,随着掺入量的增加,复合材料的玻璃化转变温度降低。PI颗粒的引入会显著提高复合材料韧性,10wt% PI改性复合材料层间剪切强度提高了41.2%,15wt% PI改性复合材料的Ⅰ型层间断裂韧性提高了156.3%。复合材料的层间能够清晰地观察到颗粒的存在;PI的质量分数进一步提高时,出现粒子团聚缺陷,导致复合材料的层间剪切强度下降。此外PI增韧邻苯二甲腈树脂复合材料在380℃下的层间剪切强度与未改性复合材料数值相当,该温度下PI颗粒的含量已不是影响复合材料韧性的主要因素。      

邻苯二甲腈树脂复合材料阻燃低毒特性研究

从热释放速率、毒性、有害气体浓度、氧指数、烟密度、水平和垂直燃烧性能等方面系统地研究了邻苯二甲腈树脂复合材料的阻燃低毒特性。在辅射强度为50kW／m^2时,邻苯甲腈复合材料的热释放速率为21kW／m^2,点燃时间为500s。同时其氧指数大于70％,烟密度小于20,表明邻苯二甲腈树脂复合材料是一种理想的阻燃低毒复合材料。     

耐高温双邻苯二甲腈树脂的合成与性能研究

使用新型固化剂3,3′,4,4′-四氨基二苯砜制得具有多重芳醚键链段的耐高温双邻苯二甲腈树脂。并对样品进行表征分析。结果表明:氮气条件下:失重率为5%时,双邻苯二甲腈树脂的温度为190℃,而耐高温双邻苯二甲腈树脂的温度为470℃;空气条件下:耐高温双邻苯二甲腈树脂在415℃时失重率为5%,在600℃时残碳率为62%;耐高温双邻苯二甲腈树脂的软化点的温度70℃左右,固化温度230℃左右,具有较低的软化温度、较长的加工窗口和较好的耐高温性。     

聚芳醚腈/双邻苯二甲腈树脂共混改性与性能研究

通过联苯型双邻苯二甲腈与聚芳醚腈熔融共混形成预聚物,经高温固化及后热处理制备了聚芳醚腈/双邻苯二甲腈共混体系,研究了其耐热性能、力学性能、形貌特征以及其微观结构与性能之间的关系。其共混体系固化物的弯曲强度,断裂弯曲应变等性能较纯双邻苯二甲腈树脂均有大幅度的提高,并且保持了纯双邻苯二甲腈树脂耐高温,高模量等优越性能。当聚芳醚腈的含量达到12%时,该体系的弯曲强度和断裂弯曲应变较纯双邻苯二甲腈固化物分别高了52.7%和61.6%,实现了热固性基体树脂的同时增韧增强而不降低耐热性的改性技术路线。     

邻苯二甲腈树脂分子结构及性能调控工作进展

邻苯二甲腈树脂是一类具有耐高温及其他优异综合性能的热固性树脂,在国防、军工等使用环境苛刻的领域中有着广泛的应用需求。但苛刻的固化工艺严重制约了邻苯二甲腈树脂的应用发展。文中梳理了本研究团队对邻苯二甲腈树脂分子结构及高性能固化剂的设计思路和方法,总结了在拓宽树脂加工窗口、降低固化温度和缩短固化时间等改善树脂固化工艺方面的研究工作,讨论了树脂分子结构和加工工艺对树脂性能调控的影响,并介绍了邻苯二甲腈树脂作为有机透波复合材料在高温环境中的性能优势。     

改性邻苯二甲腈树脂及复合材料体系研究进展

邻苯二甲腈树脂是一类新型的耐高温热固性树脂体系，为了改善其工艺性并满足严苛的环境性能需求，国内外针对邻苯二甲腈树脂体系开展了大量改性研究工作。着重从分子主链结构设计、固化方式及机理、树脂改性和复合材料改性等方面，介绍了改性邻苯二甲腈体系的研究进展，表明其具有优异的工艺性、耐候性和力学特性，展示出良好的应用前景。     

双邻苯二甲腈树脂胶黏剂的研究

合成了一种双邻苯二甲腈树脂(BPh),并以聚酰胺酰亚胺(PAI)为增韧剂,以二烯丙基双酚A改性4,4′-二氨基二苯甲烷型双马树脂(DP/BMI)为促进剂,研制出一种耐高温双邻苯二甲腈树脂胶黏剂。通过DSC和FTIR分析了该胶黏剂的固化行为,利用DMA和TGA评价了该胶黏剂的耐热性并采用材料试验机考核了该胶黏剂的粘接强度。结果表明:DP/BMI树脂能促进BPh树脂胶黏剂固化,固化温度为260℃。PAI能有效增韧BPh树脂的胶黏剂,增韧后胶黏剂蜂窝滚筒剥离强度达到21.20N·mm/mm。BPh树脂胶黏剂耐热性好,400℃剪切强度为6.38MPa,玻璃化转变温度为329.6℃。胶黏剂剪切强度耐热老化保持率在80%以上;耐湿热老化保持率在95%以上。     

可低温固化的氰基树脂体系的加工性及力学性能的初步研究

合成了一种邻苯二甲腈封端的芳醚单体和一种含有氨基的自催化型邻苯二甲腈单体,采用1 H-NMR对单体结构进行了表征.对两种单体进行熔融共混研究,得到了一种可低温固化成型的氰基树脂体系.运用DSC对该树脂体系的固化行为进行了研究,利用流变初步研究了熔体的加工性能,研究表明树脂体系有可能适用于模压及RTM工艺.运用DMA研究了不同固化温度对固化物玻璃化转变温度的影响,结果表明树脂固化物具有较好的耐热性.利用该树脂体系制备玻璃布增强复合材料,初步表征了材料的室温及高温力学性能,表明该氰基树脂体系有可能作为耐高温树脂基复合材料的基体树脂使用.     

快速固化碳纳米管/苎麻纤维/环氧树脂复合材料层板的制备与性能

针对植物纤维/树脂基复合材料高性能化问题,本研究以羟基化碳纳米管/无水乙醇分散液预先浸渍苎麻纤维织物,得到了碳纳米管分散均匀的碳纳米管/苎麻纤维多尺度复合织物,并进一步以快速固化环氧树脂为基体,采用真空辅助树脂灌注成型工艺(VARI)制备了碳纳米管改性的苎麻纤维/环氧树脂基复合材料层板(PRFC)。研究结果表明,相比未采用碳纳米管改性的苎麻纤维/环氧树脂复合材料(RFC),PRFC的弯曲强度提高14.7%,冲击强度提高20.9%。相比碳纳米管预先分散于环氧树脂基体中制备的碳纳米管改性苎麻纤维/环氧树脂复合材料(MRFC),PRFC的力学性能提高更显著。同时,PRFC的吸湿性能比MRFC和RFC的明显降低。     

Preparation, microstructure and mechanical properties of metal-particulate/glass-matrix composites

Composites with a borosilicate glass matrix containing different concentrations of vanadium particles were fabricated by powder metallurgy and hot-pressing. The mechanical properties and fracture behaviour of the composites were assessed by a range of techniques. Young's modulus, fracture strength in bending, and fracture toughness increased with vanadium content. By virtue of the good interfacial bonding and low residual internal stresses, an effective crack-particle interaction during fracture was achieved. The fracture toughness of composites containing 30 vol. % of vanadium inclusions was approximately 65 % higher than that of the unreinforced glass. Experimental values for the fracture toughness increment were in good qualitative agreement with the predictions of theoretical models in the literature. Extensive plastic deformation of the vanadium inclusions was not found, however. This was attributed mainly to the constraint imposed by the rigid matrix surrounding the particles and to possible embrittlement of the particles during composite fabrication at high temperatures. The brittleness index (B) of the composites was calculated and its relevance for characterisation of the ductile versus brittle behaviour of brittle-matrix composites is discussed.     

聚乙烯醇纤维增强钢渣粉-水泥复合材料基本力学性能及微观结构

通过掺加钢渣粉来制备聚乙烯醇（PVA）纤维增强钢渣粉-水泥基复合材料,从宏微观两个方面研究了这种复合材料的性能。考虑了基体材料的水胶比（0.25和0.35）、不同钢渣粉质量分数（0、30wt%、60wt%、80wt%）,采用抗压强度试验、薄板四点弯曲试验研究了PVA纤维增强钢渣粉-水泥基复合材料的基本力学性能变化规律及其在弯曲荷载作用下的裂缝控制能力,采用扫描电镜观测了破坏后试样的微观结构。结果表明,水胶比和钢渣粉掺量均可明显影响PVA纤维增强钢渣粉-水泥基复合材料的基本力学性能,在低水胶比条件下（水胶比为0.25）,钢渣粉掺量达到80wt%时,试样表现出较高的韧性指数和良好的裂缝控制能力,基本满足工程所需强度要求,水胶比为0.35时钢渣掺量不宜超过60wt%;同时,从节能减排的角度考虑,利用钢渣粉制备PVA纤维增强钢渣粉-水泥基复合材料是可行的。      

Flame retardant diglycidylphenylphosphate and diglycidyl ether of bisphenol-A resins containing Borassus fruit fiber composites

Natural fiber composites containing diglycidylphenylphosphate (DGPP) resin were prepared from DGPP, diglycidyl ether of bisphenol-A (DGEBA), and Borassus fruit fiber. Morphology, thermal, and mechanical properties of blends and fiber-reinforced composites were investigated. The tensile strength, flexural strength, and tensile modulus increased up to 10% addition of DGPP and decreased with high percentage of DGPP. The flexural strength of composites was increased up to 15% addition of DGPP due to good dispersion and toughening of DGPP in DGEBA. As observed by the SEM analysis, the matrix–fiber adhesion was poor in the case of 20% DGPP containing composites and failure occurred through fiber pullout whereas for composites with 5 and 10% of DGPP, interaction of fiber and matrix was strong and failure occurred through fiber breakage rather than fiber pullout. Addition up to 15% DGPP improved desired thermal and mechanical properties of these composites.     

In vitro behaviour of three biocompatible glasses in composite implants

Poly(l,dl-lactide) composites containing filler particles of bioactive glasses 45S5 and S53P4 were compared with a composite containing a slowly dissolving glass S68. The in vitro reactivity of the composites was studied in simulated body fluid, Tris-buffered solution, and phosphate buffered saline. The high processing temperature induced thermal degradation giving cavities in the composites containing 45S5 and S53P4, while good adhesion of S68 to the polymer was observed. The cavities partly affected the in vitro reactivity of the composites. The degradation of the composites containing the bioactive glasses was faster in phosphate buffered saline than in the two other solutions. Hydroxyapatite precipitation suggesting bone tissue bonding capability was observed on these two composites in all three solutions. The slower dissolution of S68 glass particles and the limited hydroxyapatite precipitation suggested that this glass has potential as a reinforcing composition with the capability to guide bone tissue growth in biodegradable polymer composites.     

Impact resistance and energy absorption mechanisms in hybrid composites

The response of hybrid composites to low-velocity impact loading has been investigated. The energy absorbing mechanisms of laminates containing various fibers were studied primarily by means of the instrumented falling dart impact testing technique. Static indentation tests and scanning electron microscopy (SEM) were also employed to assist in the identification of failure mechanisms. The composites containing polyethylene (PE) fibers, which were of high strength and high ductility, were found to be effective in both dissipating impact energy and resisting through penetration. Polyester (PET) fiber reinforced epoxy also exhibited superior impact characteristics even though the PET fabric layers without epoxy did not have good modulus or ductility. Good energy absorbing capability was also observed in epoxy reinforced with woven fabrics made of high-performance Nylon fibers. Nylon, PE and PET fibers were found to enhance the impact resistance of graphite fiber composites. Upon impact loading, the composites containing either PE or PET fibers in general exhibited a great degree of flexural plastic deformation and some level of delamination, thereby dissipating a significant amount of strain energy. Hybrids containing Nylon fabric showed analogous behavior, but to a lesser degree. The stacking sequence in hybrid laminates was found to play a critical role in controlling plastic deformation and delamination. This implies that the stacking sequence is a major factor governing the overall energy sorbing capability of the hybrid structure. The penetration resistance of hybrid composites appeared to be dictated by the toughness (strength plus ductility) of their constituent fibers. The fiber toughness must be measured under high strain rate conditions.     

Fabrication and properties of PZT-ordinary Portland cement composites

Lead zirconate titanate (PZT)-ordinary Portland cement (OPC) composites were fabricated using 40%, 50% and 60% of PZT by volume. The dielectric constants of the composites were found to be 139, 176 and 290 for composites containing 40%, 50% and 60% PZT respectively. Successful poling of the composites was achieved and the measured piezoelectric coefficient (d₃₃) of the composites increased with PZT content. Measured d₃₃ values for the composites with 50% and 60% PZT content were 26 and 42 pC/N respectively. These are very promising results with very high d₃₃ values for PZT-cement composites. Moreover, using this fabrication method it is possible to produce PZT-OPC composites with more than 50% PZT by volume and that these composites have good potential for use in structural applications.     

感应烧结Fe-Cu-Al-石墨复合材料的力学性能和摩擦学性能

为了进一步提高材料的力学性能和摩擦学性能,以感应加热烧结的方法,制备了Fe-Cu-Al-石墨复合材料。利用XRD,EDS,SEM等分析了复合材料的组成、结构、表面形貌;研究了其力学性能、摩擦学性能及磨损机理。结果表明：Fe-Cu-A1-石墨复合材料具有多孔结构;随着石墨含量的增加,复合材料的力学性能降低,摩擦学性能提高...     

铝/石墨复合材料高速高温下的摩擦磨损特性

本文研究了用中间法新工艺制造的铝石墨复合材料在高速高温下的摩擦磨损特性。试验在销盘式试验机上进行。滑动线速度最高达9.4米/秒。在2米/秒干摩擦时,所有测试的复合材料磨损量均小于基体合金。200℃时,含石墨2～5%的复合材料磨损量也此基体合金小。在9.4米/秒干摩擦时,含石墨2%的复合材料耐磨性能最好。以前曾有报导:滑动线速度大于1米/秒,铝石墨复合材料的磨损量大于基体合金[12,13]。本文认为新工艺制造的复合材料在9.4米/秒的高速摩擦时摩擦系数和磨损量下降是由于石墨与基体界面结合良好。      

微量碳纤维/树脂复合吸波材料的研究

分别研究了平行和正交排布碳纤维复合材料的微波吸收特性，并对碳纤维的吸波机理和吸波性能的影响因素（纤维间距、支数）作了初步探讨。结果表明：碳纤维平行排布吸波材料只在入射电场方向与纤维排布方向平行时具有吸波性能；随纤维间距的减小，其反射衰减曲线的最大吸收峰向高频方向移动；纤维支数增大，吸波性能增强。正交排布碳纤维的吸波性能与纤维的间距密切相关。本实验条件下当纤维间距为8mm时，可获得有效带宽4．7GHz、最大吸收峰值-21．6dB的反射衰减。     

The effect of silane coupling agent on the sliding wear behavior of nanometer ZrO<Subscript>2</Subscript>/bismaleimide composites

The polymer composites filled with nanoparticles have good friction and wear properties and widely used in many fields. The performances of nanocomposites are influenced extensively by the nanoparticles morphology, size, volume fraction and dispersion. Nanometer ZrO₂ particles have good properties, lower prices and shows good foreground in resist-materials of polymer composites. In this paper, the nanometer ZrO₂ particles are treated by silane coupling agent of N-(2-aminoethyl)-γ-aminopropylmethyl dimethoxy silane. The effect of nanometer ZrO₂ content and silane coupling agent on the friction and wear properties of BMI copmposites filled with nanometer ZrO₂ are investigated. The composites filled with untreated ZrO₂ and treated ZrO₂ are prepared by the same way of mechanical high shear dispersion process and casting method. The sliding wear performance of the nanocomposites is studied on an M-200 friction and wear tester. The experimental results indicate that the frictional coefficient and the wear rate of the composites can be reduced by filled with nanometer ZrO₂. The composites containing treated nanometer ZrO₂ have the better tribological performance than that containing untreated nanometer ZrO₂. The results are explained from the SEM morphologies of the worn surface of matrix resin and the composites containing nanometer ZrO₂ and the TEM photographs of the nanometer ZrO₂ dispersion in the matrix.