运动训练器材用碳纤维复合材料的湿热老化行为研究

采用真空辅助成型的方法制备运动训练器材碳纤维复合材料层合板,研究了40℃和60℃的湿热老化环境下碳纤维复合材料的吸湿率、拉伸强度、弯曲强度、压缩强度和剪切强度变化,并观察了不同老化条件下的拉伸断口形貌。结果表明,温度越高,运动训练器材碳纤维复合材料的平衡吸湿率、线性段斜率和扩散系数越大。当湿热老化温度为40℃和60℃时,随着老化时间延长,碳纤维复合材料的拉伸强度、弯曲强度都先增后减,分别在老化时间为14d和7d时取得最大值。当湿热老化温度为40℃和60℃时,随着老化时间延长,碳纤维复合材料的压缩强度先增大后减小,在老化时间为35d时取得最大值。当湿热老化温度为40℃时,随着老化时间延长,碳纤维复合材料的剪切强度先增大后减小,在老化时间为7d时取得最大值;当湿热老化温度为60℃时,随着老化时间延长,碳纤维复合材料的剪切强度逐渐减小。碳纤维复合材料在湿热环境下的力学性能变化,主要与温度和湿度共同作用下碳纤维复合材料的增塑和固化有关。     

新型扩容导线用玻纤／碳纤复合芯恒温热老化研究

玻纤／碳纤维复合芯热老化是影响新型电力输电导线服役寿命的关键因素。本研究对输电导线玻纤／碳纤复合芯进行了人工加速老化试验,重点研究了老化过程中复合芯质量和机械性能变化,并利用复合芯微观组成变化对老化机理进行了分析。人工加速老化试验结果表明,在160℃进行了6000h高温热老化试验后,复合芯的质量、弯曲强度和拉伸强度保持率分别为96．5％,90．5％与81．5％,新型导线用复合芯表现出优异的耐热老化行为;复合芯的热老化行为与小分子分解速率和氧气扩散反应速率相关,长期热氧老化会腐蚀树脂基体,在复合芯表面形成疏松的玻纤层,进而影响到复合芯的机械性能。     

无卤阻燃增强PA66/PA6合金的性能研究

基于二乙基次膦酸铝和亚磷酸铝复配阻燃体系,研究了不同PA66和PA6比例时,阻燃增强PA66/PA6合金的力学性能、阻燃性能、电学性能、耐热性能以及湿热老化后的性能变化。随着合金中PA6比例的提高,材料的力学强度有略微下降,韧性相关指标略微提升,热变形温度和阻燃性能有所衰减。85℃/85RH%长期湿热老化试验结果显示,随合金中PA6比例的提高,材料吸水率逐渐增加,湿态下保持的拉伸强度更低,韧性更高,湿热老化后合金材料均未出现阻燃剂析出现象。无卤阻燃增强PA66/PA6合金的拉伸强度和绝缘电阻均随着温度升高而降低,PA6比例越高,合金材料的拉伸强度和绝缘电阻降低程度越明显。     

纤维张力及均匀性对输电导线复合芯性能影响

讨论了碳纤维复合芯拉挤工艺中纤维张力及张力均匀性对复合芯强度及成本的影响。试验利用纤维张力计测定碳纤维复合芯拉挤生产过程中的纤维张力,研究了不同张力条件下碳纤维复合芯抗拉强度、卷绕性能与张力关系,同时通过控制纤维张力的均匀性研究纤维张力均匀性与复合芯径向耐压强度的关系。试验结果表明,纤维张力的大小及均匀性对拉挤复合芯棒综合性能具有明显的影响,复合芯拉伸强度随着纤维张力的增加逐渐增加,当张力控制在0.6%纤维强力时为最佳制备工艺;纤维张力的均匀性提高,且复合芯棒的径向耐压性能提高。通过控制纤维张力可以相应减少碳纤维原材料用量,达到降低碳纤维复合芯成本的目的,有利于碳纤维复合芯导线的大规模推广应用。     

两种玻璃纤维增强复合材料体系的湿热老化研究

玻璃纤维增强复合材料在湿热环境下性能的退化是工程研究中待解决的问题,而实验室人工加速老化则是较好地研究该问题的常用方法。通过人工加速老化方法,结合露天储水环境,研究两种玻璃纤维增强复合材料在35℃水浸泡、65℃水浸泡及盐雾三种环境下的吸水率、巴氏硬度和弯曲强度的变化,并运用两种模型预测材料的使用寿命。研究表明:不同湿热环境下,材料的巴氏硬度前期变化明显,后期趋向稳定;吸水率基本符合Fick定律;温度对弯曲强度保留率影响显著,盐雾影响次之;中值老化公式比经验公式拟合度高7.6%。     

碳纤维复合芯导线中芯棒成型工艺的探讨

简介了碳纤维复合材料（CFRP）芯棒在新型碳纤维复合芯导线中的应用,探讨了CFRP芯棒制造的工艺要点。表明目前CFRP芯棒连续成型速度已达到1 000 mm/min,可选用玻璃化转变温度（Tg）200℃的树脂体系;指出性能优异、品质稳定和价格适中的CFRP芯棒,将在国内架空输电线路得到更多的应用。     

碳纤维复合芯导线舞动及扭转损伤特性研究

碳纤维复合芯导线运行过程长期受舞动与扭转作用,其主承力部件环氧树脂增强碳纤维复合材料芯棒韧性较差,在舞动或扭转工况下,复合材料芯棒能否可靠运行是电网运行部门关注的关键问题。利用导线舞动与扭转试验,通过研究不同舞动次数后复合芯棒的结构与机械性能,客观评价复合芯导线的安全适用性。研究结果表明,碳纤维导线在25%额定拉断力下舞动90万次后铝线全部断股,而碳纤维复合芯在连续舞动100万次的情况下,其抗拉强度依然保持在90%初始强度以上,复合芯无损探伤检测亦未发现芯棒破坏。碳纤维复合芯在25%RTS张力下连续扭转100万次后,铝线未发生断股现象,其抗拉强度保持在90%初始强度以上,两种严酷工况试验证明碳纤维复合芯可在高电压等级分裂导线中长期安全使用。     

湿热老化对环氧灌封胶粘接性能的影响研究

分别制备出脂肪胺、芳香胺、酸酐和潜伏性固化体系的环氧灌封胶产品。利用高加速湿热试验,研究了高加速湿热老化环境下,此四种固化体系环氧的吸湿性能和拉伸剪切性能的衰减情况,并研究了高加速湿热老化环境,对脂肪胺固化环氧树脂灌封胶对不同基材、不同填料下的拉伸剪切的影响。结果表明,芳香胺固化的环氧,在高加速湿热老化环境(120℃,100%RH)下老化480h,拉剪强度衰减最小,约30%。并且,通过添加片状铝粉或硅微粉,芳香胺为固化剂,有望制得耐湿热性能较好的环氧灌封胶产品。     

T700碳纤维复合材料耐湿热老化研究

选用TDE-85和E-51作为主体树脂,制备了一种T700碳纤维复合材料,并对这种复合材料进行耐湿热老化研究,分别测定其抗剪切强度、抗拉伸强度及模量和玻璃化转变温度随老化时间的变化值。结果表明,该T700碳纤维复合材料耐湿热老化性能较好,其力学性能在2 000 h的老化过程中变化不太大,但是其玻璃化转变温度值降低很多。     

碳纤维/聚三唑树脂复合材料的湿热老化行为

本文研究了碳纤维/聚三唑树脂复合材料(T700/PTA)在80℃、相对湿度98%条件下的湿热老化行为。分别采用静态力学性能测试、吸湿称重、动态热机械分析、扫描电子显微镜观察等手段考察了复合材料在湿热条件下的力学性能变化、吸湿特性和形貌变化;利用半经验数学模型对复合材料进行强度拟合和寿命预测。结果表明,复合材料的弯曲强度、层间剪切强度受湿热影响显著,尤其在老化初期;复合材料吸湿第一阶段符合Fick扩散定律,扩散系数D=1.129×10-6mm2/s;吸湿后试样的动态热机械分析谱图上出现两个转变,干燥后次级转变消失;湿热老化后,纤维与树脂基体之间的界面作用减弱;利用数学模型预测复合材料弯曲强度保留率为50%时的老化寿命为33600h,T700/PTA复合材料具有优良的耐湿热老化性能。     

Effects of hygrothermal aging on the thermomechanical properties of a carbon fiber reinforced epoxy sheet molding compound: An experimental research

Carbon fiber sheet molding compounds (C-SMCs) are discontinuous fiber reinforced composite materials. Among them, epoxy-based C-SMCs are becoming relevant materials due to their high thermomechanical performance and better formability than continuous fiber reinforced composites. The thermomechanical performance of epoxy resins and epoxy based continuous carbon fiber composites have shown to be influenced by hygrothermal aging. In this work, this influence is studied for an epoxy-based C-SMC. Epoxy-based C-SMC samples were hygrothermally aged by means of accelerated conditioning, exposing them to 65% relative humidity, and 80°C in a climatic chamber. The equilibrium moisture content, as well as the moisture diffusion coefficient has been determined. The thermomechanical properties of epoxy C-SMC have been analyzed by dynamic mechanical analysis, tensile, 3-point bending, and short beam tests in dry and aged samples. The results showed that epoxy C-SMC is affected by hygrothermal aging in the cases of moisture intake and its effects on T_g value, but interestingly, the hygrothermal aging did not generate any degradation effects in the mechanical response of epoxy C-SMC.     

湿热环境下泡桐木复合材料夹芯结构Ⅰ型界面剥离试验研究

采用人工加速老化的方法模拟湿热环境,通过泡桐木玻璃纤维增强复合材料夹芯结构的双悬臂梁拉伸剥离试验,研究湿热环境对玻璃纤维增强复合材料(GFRP)面板和泡桐木芯材的粘结性能的影响。试验结果表明,90 d湿热加速老化后泡桐木复合材料夹芯结构的能量释放率下降了32.3%,芯材泡桐木顺纹抗拉强度下降了11.6%,GFRP面板拉伸模量下降了11.0%。     

Hygrothermal degradation of the composite laminates from woven carbon/SC‐15 epoxy resin and woven glass/SC‐15 epoxy resin

The degradation mechanism for hygrothermal aging of woven carbon‐epoxy and woven glass‐epoxy composite laminates was investigated in the micro‐scale. Interlaminar shear and cross laminar flexural tests were performed on notched and unnotched specimens to know the mechanical performance of the composite laminates. The Interlaminar Shear Stress (ISS) for both the composites was also evaluated and correlated with the number of hygrothermal cycles. Four‐point bending and tensile or compression shear loading configurations were also used. The stress at the onset of delamination (Delamination Damage Tolerance, DDT) was identified from the load‐deflection curve of the flexural specimens and correlated with the number of hygrothermal cycles. It was found that both the ISS and DDT decrease with the exposure time. Dimensional stability was almost unchanged throughout the aging process, although there was a very little moisture absorption (∼1.3%) in glass‐epoxy and carbon‐epoxy composite laminates. SEM photomicrographs of the delaminated surface show that failure occurs suddenly in a macroscopically brittle mode by crack initiation and propagation method. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.     

紫外老化对UP/GF层合板性能的影响

对玻璃纤维增强不饱和聚酯树脂(UP/GF)基层合板进行了人工紫外加速老化试验,分析了试样紫外老化前后的巴氏硬度、质量保持率以及拉伸、弯曲性能的演变规律。结果表明,随紫外老化时间的增加,试样的巴氏硬度呈先上升后下降的趋势;紫外老化最初的168 h内,质量损失率占整体质量损失的近50%,之后保持在一个相对平稳的状态;其拉伸强度和弯曲强度在紫外老化前期有所上升,在紫外老化168 h开始下降;从傅立叶变换红外光谱图中可以看出,试样中没有新的物质产生,只是化学结构发生了变化;紫外老化后,UP含量明显减少,在拉伸断裂过程中,有明显的玻璃纤维从UP树脂中拔出而留下凹槽空洞。     

EVAC/ADP/MPP复合材料的抗老化性能

在乙烯–乙酸乙烯共聚物(EVAC)/二乙基次膦酸铝(ADP)/三聚氰胺聚磷酸盐(MPP)复合材料中加入紫外线吸收剂UV–531和抗氧剂1010,并对其进行老化性能研究,主要研究了"双85"湿热老化以及紫外老化对其力学性能以及热稳定性的影响。研究结果表明,经过"双85"湿热老化后,EVAC/ADP/MPP复合材料的拉伸强度和断裂伸长率都呈现出先上升后下降的趋势。经过紫外老化试验的EVAC/ADP/MPP复合材料的拉伸强度和断裂伸长率却都呈现出不断下降的趋势。通过红外光谱研究发现,EVAC/ADP/MPP在"双85"湿热老化试验时老化降解在乙烯和乙酸乙烯链段同时进行,而在紫外老化试验中老化降解主要发生在乙烯链段;热失重以及差示扫描量热分析发现,经过长时间的湿热以及紫外老化试验之后EVAC/ADP/MPP复合材料的热稳定性变差、残炭量变少。     

Influence of polyacrylate/titanium dioxide composite particles on the antiaging performance of polycarbonates

Polycarbonate (PC) and PC modified by polyacrylate/TiO₂ composite particles were exposed both in an outdoor environment with typical humid and hot climatic conditions in the Jiangjin area and in an indoor hygrothermal environment for accelerated aging. Then, the effects of the polyacrylate/TiO₂ composite particles on the antiaging performance of PC were investigated by measurement of the mechanical properties of PC before and after aging. The results show that the mechanical properties of PC decreased a lot after aging by the outdoor environment of the Jiangjin area. After accelerated aging by the indoor hygrothermal environment, the tensile strength and the bending strength of PC increased a little, and the elongation at break of PC decreased. The polyacrylate/TiO₂ composite particles effectively increased the elongation at break of PC aged by the hygrothermal environment and outdoor aging. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

聚醚醚酮/碳纤维复合粉末的制备及性能

将热处理改性的聚醚醚酮(PEEK)粉末和碳纤维(CF)共混制备了PEEK/CF复合粉末。采用表观密度测试、扫描电子显微镜、电子万能试验机、热重分析、差示扫描量热法等对复合粉末材料的微观形貌、力学性能和热性能进行分析。结果表明,热处理后的PEEK粉末表观密度最高可达0.286 g/cm3。与纯PEEK相比,复合粉末的玻璃化转变温度、熔融温度和分解温度都有较大的提高;随着CF质量分数逐渐增加,复合粉末材料的拉伸强度、弯曲强度、弯曲弹性模量、热变形温度和维卡软化温度逐渐增大,冲击强度逐渐减小。改性PEEK/CF复合粉末材料为选择性激光烧结技术提供了高强度、高耐热性能的粉末材料,从而应用于汽车工业、电器工业、医疗器械和航空航天等领域。     

Structural degradation and mechanical fracture of hybrid fabric reinforced composites

This investigation involves the study of accelerated environmental aging in two polymer composite laminates reinforced by hybrid fabrics based on carbon, Kevlar and glass fibers. Composite laminate configurations are defined as a laminate reinforced with E‐glass fiber and Kevlar 49 fiber hybrid fabric (GK) and another laminate reinforced with E‐glass fiber and AS4 carbon fiber hybrid fabric (GC). Both laminates were impregnated with epoxy vinyl ester thermosetting resin (Derakane 470‐300) consisting of four layers. Morphological studies (photo‐oxidation process and structural degradation) of environmental aging were conducted, in addition to comparative studies of the mechanical properties and fracture characteristics under the action of uniaxial tensile and three‐point bending tests in specimens in the original and aged conditions. With respect to uniaxial tensile tests for both laminates, good mechanical performance and little final damage (small loss of properties) was caused by the aging effect. However, for the three‐point bending tests, for both laminates, the influence of aging was slightly higher for all parameters studied. The low structural deterioration in the laminates is attributed to the high performance with the heat of the matrix (Derakane 470‐300) and the characteristics of the hybrid fabric, exhibiting fiber/matrix interface quality. POLYM. ENG. SCI., 56:657–668, 2016. © 2016 Society of Plastics Engineers