中温固化氰酸酯基体树脂的研制

研制出具有良好中温固化活性的改性氰酸酯树脂,对树脂的反应活性、力学性能、介电性能、动态热机械行为和黏温特性进行了研究。树脂在125℃固化后具有较高的力学性能、耐热性和较低的介电损耗。树脂在180℃后处理后力学性能和Tg无明显变化,介电损耗稍有降低。氰酸酯预浸料具有良好的黏温特性,可用于制备中温固化氰酸酯预浸料。     

PBO纤维与石英纤维混编增强氰酸酯树脂基复合材料的研究

结合PBO纤维增强树脂基复合材料优异的介电性能和石英纤维增强树脂基复合材料优异的力学性能,本文设计了石英纤维与PBO纤维体积比55∶45混合编织,同时采用空气气氛对混编纤维表面进行等离子体处理,等离子体处理工艺为400W/10min,制备的氰酸酯树脂复合材料力学性能较纯PBO纤维增强氰酸酯树脂复合材料具有更加优异的性能,弯曲强度提高了62%,层间剪切强度提升了231%,大大加快了PBO纤维复合材料在透波复合材料领域的应用步伐。     

中空夹芯织物预浸料的制备与性能表征

采用不饱和树脂与中空夹芯织物进行复合制备中空夹芯织物预浸料,研究中空夹芯织物预浸料的制备工艺,并对中空夹芯织物预浸料的站立性、中空复合材料的力学性能、电性能进行表征。结果表明,高度为3 mm的中空夹芯织物预浸料的树脂含量为50%时站立性最好,预浸料固化后中空复合材料的拉伸强度达40.04 MPa,压缩强度达6.63 MPa,介电常数为1.9,损耗角正切值为0.006。     

5528氰酸酯树脂性能研究

对新型的5528改性氰酸酯树脂的介电性能、耐热性能、粘温特性和吸湿性能进行了研究,结果表明:5528氰酸酯树脂具有良好工艺性能,适合于湿法预浸和热熔预浸,介电性能优异,介电损耗正切值为0.005 26,远远低于纯氰酸酯固化物,而且对于频率的稳定性更好,适合宽频应用5。528氰酸酯树脂体系是适合高性能透波材料或高频印刷电路板应用的树脂基体。     

单官能氰酸酯改性氰酸酯胶粘剂的性能研究

为了获得更好介电性能的氰酸酯胶粘剂材料,采用自合成的单官能团氰酸酯改性氰酸酯树脂.研究了单官能氰酸酯对胶粘剂的反应活性、介电性能、力学性能以及动态热机械行为的影响.自制促进剂对氰酸酯树脂的固化具有较高的促进作用,配合单官能氰酸酯能实现中温固化.研究结果表明,单官能氰酸酯能有效提高固化反应程度、介电性能和力学性能.当单官...     

石英纤维布/J-284PD氰酸酯树脂复合材料的制备与性能

采用热压罐成型的方法制备了石英纤维布/J-284PD氰酸酯复合材料,并验证了其力学性能、介电性能和耐湿热性能。结果表明:中温固化的石英纤维布/J-284PD复合材料,其介电性能、力学性能和耐湿热性能优异,其中拉伸强度为630 MPa,层间剪切强度为58.8 MPa,介电常数为3.1,损耗角正切为0.003;经过10 d湿热试验后,性能最大仅下降10%。     

酚醛型环氧树脂改性氰酸酯复合材料性能的研究

通过DSC分析,粘度、介电性能、力学性能及耐油性测试对酚醛型环氧树脂改性氰酸酯树脂复合材料的性能进行了研究。结果表明,改性氰酸酯树体系在70～160℃具有较低的粘度,理想工艺是在125～130℃下30～45min后开始加压;改性氰酸酯树脂表观活化能和反应级数分别为60.81kJ/mol和0.8846。改性氰酸酯复合材料具有良好的力学性能、介电性能和耐油性能。     

磷酸盐基体及其纤维复合材料的研究--预浸料制备及其成型工艺

本文对无机磷酸盐体系进行研究，考察了磷／金属元素摩尔比(P／M)、含水量变化对胶粘剂性能的影响以及基体胶P／M变化对基体胶性能的影响，确定了合适的胶粘剂和基体胶配比，并用其制预浸料。通过热失重TGA分析以及考察加工成型过程中工艺参数变化对复合材料介电性能、力学性能的影响，优化了预浸料热压成型工艺条件。     

一种改性氰酸酯树脂性能的研究

采用自制改性剂改性双酚A型氰酸酯树脂,制备了一种适合常规180℃固化工艺的改性氰酸酯树脂,可用于热熔法制备预浸料。对改性氰酸酯树脂的工艺性、力学性能、耐热性能和微观形貌等进行了研究,结果表明制备的树脂具有良好的工艺性,无需进行高温后固化处理即可得到力学性能和耐热性能较为优异的固化物,可广泛用于航空、航天、电子等领域高性能复合材料的制备。     

石英纤维增强氰酸酯树脂基复合材料性能研究

研究了QF210石英纤维增强新型的改性氰酸酯树脂基复合材料的耐热性、力学性能和介电性能,结果表明5528A／QF210复合材料具有优良的力学性能和优异的介电性能,可在150℃下使用。尤其是5528A／QF210复合材料的介电性能具有极好的频率稳定性,适合作为宽频高透波材料。     

碳纳米管定向排列增强碳纤维/环氧树脂复合材料制备及力学性能

采用高频电场诱导法制备了碳纳米管定向有序填充的碳纤维/环氧树脂复合材料。研究了电场频率对复合材料力学性能的影响规律,对复合材料的显微形貌进行观察。结果表明:在富树脂区碳纳米管沿着电场方向存在明显的有序排列现象;高频电场诱导后复合材料的层间剪切强度最大提高28.9%,压缩强度提高28.83%,弯曲强度提升15.01%,断口粗糙度增加,树脂与碳纤维的界面结合状态改善。     

Preparation and characterization of quartz‐fiber‐cloth‐reinforced,polymerization‐of‐monomer‐reactant‐type polyimide substrates with a high impact strength

A series of novel quartz‐fiber‐cloth‐reinforced polyimide substrates with low dielectric constants were successfully prepared. For this purpose, the A‐stage polyimide solution was first synthesized via a polymerization‐of‐monomer‐reactant procedure with 2,2′‐bis(trifluoromethyl)benzidine and 3,3′,4,4′‐oxydiphthalic anhydride as the monomers, and cis?5‐norbornene‐endo‐2,3‐dicarboxylic anhydride as the endcap. Then, an A‐stage polyimide solution (TOPI) was impregnated with quartz‐fiber cloth (QF) to afford the prepregs, which were thermally molded into the final substrate composites. The influence of the curing temperature and the resin content on the mechanical properties of the composite were examined. The composites exhibited a high glass‐transition temperature over 360°C, a low and steady dielectric constant below 3.2 at a test frequency of 1–12 GHz, and a volume resistance over 1.8 × 10¹⁷ Ω cm. Meanwhile, they also showed a high mechanical strength with flexural and impact strengths in ranges 845–881 MPa and 141–155 KJ/m², respectively. The excellent mechanical and thermal properties and good dielectric properties indicated that they are good candidates for integrated circuit packaging substrates. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42358.     

The influence of chemical surface modification on the performance of sisal‐polyester biocomposites

This article concerns the effectiveness of various types and degrees of surface modification of sisal fibers involving dewaxing, alkali treatment, bleaching cyanoethylation and viny1 grafting in enhancing the mechanical properties, such as tensile, flexural and impact strength, of sisal‐polyester biocomposites. The mechanical properties are optimum at a fiber loading of 30 wt%. Among all modifications, cyanoethylation and alkali treatment result in improved properties of the biocomposites. Cyanoethylated sisal‐polyester composite exhibited maximum tensile strength (84.29 MPa). The alkali treated sisal‐polyester composite exhibited best flexural (153.94 MPa) and impac strength (197.88 J/m), which are, respectively, 21.8% and 20.9% higher than the corresponding mechanical properties of the untreated sisal‐polyester composites. In the case of vinyl grafting, acrylonitrile (AN)‐grafted sisal‐polyester composites show better mechanical properties than methyl‐methacrylate (MMA)‐grafted sisal composites. Scanning electron microscopic studies were carried out to analyze the fiber‐matrix interaction in various surface‐modified sisal‐polyester composites.     

连续碳纤维增强聚醚醚酮复合材料的制备及力学性能

采用自主研发的连续碳纤维/聚醚醚酮热熔法预浸料(HC2110),通过热压成型工艺制备了复合材料层合板。测试了复合材料的力学性能,表征了微观形貌和破坏模式。预浸料热性能测试表明,HC2110预浸料较国外材料(TC1200)的耐热性及成型工艺性较优。微观形貌分析表明,复合材料层合板中纤维分布均匀性对0°拉伸性能影响较小;而纤维和树脂的界面结合较差是导致90°拉伸强度明显偏低的主要原因。     

Nonwoven polylactic acid and flax biocomposites

Flax fiber‐reinforced polylactic acid (PLA) biocomposites were made using a new technique incorporating an air‐laying nonwoven process. Flax and PLA fibers were blended and converted to fiber webs in the air‐laying process. Composite prepregs were then made from the fiber webs. The prepregs were finally converted to composites by compression molding. The relationship between the main process variables and the properties of the biocomposite was investigated. It was found that with increasing flax content, the mechanical properties increased. The maximum tensile strength of 80.3 MPa, flexural strength of 138.5 MPa, tensile modulus of 9.9 GPa and flexural modulus of 7.9 GPa were achieved. As the molding temperature and molding time increased, the mechanical properties decreased. The thermal and morphological properties of the biocomposites were also studied. The appropriate processing parameters for the biocomposites were established for different fiber contents. POLYM. COMPOS., 34:1611–1619, 2013. © 2013 Society of Plastics Engineers     

The influence of fiber surface modification on the mechanical properties of coir‐polyester composites

Coir, an important lignocellulosic fiber, can be incorporated in polymers like unsaturated polyester in different ways for achieving desired properties and texture. But its high level of moisture absorption, poor wettability and insufficient adhesion between untreated fiber and the polymer matrix lead to debonding with age. In order to improve the above qualities, adequate surface modification is required. In our present work, fiber surface modification was effected through dewaxing, alkali (5%) treatment, aqueous graft copolymerization of methyl methacrylate (MMA) onto 5% alkali treated coir for different extents using CuSO₄ – NaIO₄ combination as an initiator system and cyanoexhylation with a view to improve the mechanical performance of coir‐polyester composites. Mechanical properties like tensile strength (PS), flexural strength (ES) and impact strength (IS) of the composites as a function of fiber loading and fiber surface modification have been evaluated. Composites containing z5 wt% of fiber (untreated) improved tensile and flexural strength by 30% and 27% respectively in comparison to neat polyester. The work of fracture (impact strength) of the composite with 25 wt% fiber content was found to be 967 J/m. The elongation at break of the composites exhibits an increase with the introduction of fiber, All types of surface modification result In improved mechanical properties of the composites. Significant improvement in mechanical strength was also observed for composites prepared from 5% PMMA grafted fiber.     

酸化石墨烯改性环氧树脂及其碳纤维复合材料力学性能研究

针对石墨烯在复合材料增强增韧上的应用,对石墨烯进行了酸化处理,采用超声分散方法制备酸化石墨烯/环氧树脂(EP)浇注体,并在此基础上制备了酸化石墨烯/碳纤维(CF)/环氧树脂(EP)复合材料。分别利用红外光谱和透射电镜表征了酸化石墨烯表面结构和微观形貌,利用拉伸、弯曲、冲击等机械测试手段评价了酸化石墨烯改性EP和CF-EP的力学性能,并利用扫描电镜对复合材料拉伸断面形貌进行观察。试验结果表明:石墨烯酸化处理后,成功在表面引入了羟基、羧基等极性基团;酸化石墨烯可对EP和CF/EP进行有效增强增韧,当其添加量为0.2wt%时,EP拉伸强度和冲击强度分别提高了23.3%和109.8%,CF/EP拉伸强度、弯曲强度分别提高了6.0%和10.6%,当酸化石墨烯添加量为0.5wt%时,CF/EP复合材料层间剪切强度提高了7.4%。微观形貌分析表明,酸化石墨烯对CF/EP增强改性主要是通过对EP进行增强增韧,同时提高CF和EP之间的界面性能来实现的。     

Tribological behavior of short‐fiber‐reinforced polyimide composites under dry‐sliding and water‐lubricated conditions

Polyimide composites reinforced with short‐cut fibers such as carbon, glass, and quartz fibers were fabricated by the polymerization of monomer reactants process. The mechanical properties of the composites with different fiber contents were evaluated. The friction and wear properties of the polyimide and its composites were investigated under dry‐sliding and water‐lubricated conditions. The results indicated that the short‐carbon‐fiber‐reinforced polyimide composites had better tensile and flexural strengths and improved tribological properties in comparison with glass‐fiber‐ and quartz‐fiber‐reinforced polyimide composites. The incorporation of short carbon fibers into the polyimide contributed to decreases in the friction coefficient and wear rate under both dry and water‐lubricated conditions and especially under water lubrication because of the boundary lubrication effect of water. The polyimide and its composites were characterized by plastic deformation, microcracking, and spalling under both dry and water‐lubricated conditions, which were significantly abated under the water‐lubricated condition. The glass and quartz fibers were easily abraded and broken; the broken fibers transferred to the mating metal surface and increased the surface roughness of mating stainless steel, which led to the wear rate increasing for the glass‐fiber‐ and quartz‐fiber‐reinforced polyimide composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Development and physico‐mechanical behavior of LDPE–sisal prepreg‐based composites

Low‐density polyethylene (LDPE)‐coated sisal fiber prepreg was prepared by using solution coating process. These coated fiber prepregs were consolidated to make composites having different weight fraction of sisal fibers in a hot compression‐molding machine. This experimental study reveals that higher loading of sisal fiber up to 57wt% in LDPE–sisal composites is possible by this technique. Mechanical and abrasive wear characteristics of these composites were determined. The tensile strength of composites increased with the increase in sisal fiber concentration. Coating thickness of LDPE was varied by changing the viscosity of LDPE–xylene solution that manifested to different weight fraction of fiber in sisal–LDPE composites. Mechanical, dynamic mechanical, and abrasive wear characteristics of these composites were determined. The tensile strength and modulus of sisal composites reached to 17.4 and 265 MPa, respectively, as compared to 7.1 and 33MPa of LDPE. Storage modulus of sisal composites LD57 reached to 2.7 × 10⁹ MPa at 40°C as compared to 8.1 × 10⁸ MPa of LDPE. Abrasive wear properties of LDPE and its composites were determined under multi‐pass mode; pure LDPE showed minimum specific wear rate. The specific wear rate of composites decreased with the sliding distance. Increase of coated sisal fiber content increased the specific wear rate at all the sliding distances, which has been explained on the basis of worn surface microstructures observed by using SEM. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

石英纤维织物增强复合材料性能研究

本文分别研究了QW280和TC 8/3-K-TO石英纤维织物/改性环氧树脂复合材料的力学性能和介电性能,结果表明QW280/改性环氧树脂复合材料与TC 8/3-K-TO/改性环氧树脂复合材料力学性能和介电性能基本相当.