超高模量聚乙烯纤维-碳纤维混杂复合材料冲击性能的研究

本工作以平面Charpy冲击、缺口与非缺口Charpy冲击全面地研究了本实验所制备的超高模量聚乙烯(UHMPE)纤维-碳纤维混杂增强环氧复合材料的冲击性能。同时根据试样在冲击过程中的载荷-时间曲线以及试样在冲击破坏后的形貌对该类混杂复合材料的冲击破坏过程与冲击破坏模式进行了分析。结果表明,将UHMPE纤维与碳纤维相混杂,复合材料的冲击性能呈现出明显的正混杂效应。     

剑麻纤维/酚醛树脂复合材料的动态力学性能、力学性能和热性能

采用碱处理方法对剑麻纤维(SF)进行处理、细化,通过模压成型制备剑麻纤维/酚醛树脂(SF/PF)复合材料.采用动态力学(DMA)、力学性能、热膨胀性能等测定研究了剑麻纤维的加入量对复合材料的动态力学性能、冲击强度、弯曲强度、弯曲模量、比强度、比模量、耐磨性能、热膨胀性能的影响,用扫描电镜(SEM)观察了材料冲击断面和磨损面的形态.结果表明,制得的SF/PF复合材料的α转变温度提高,贮存模量提高,材料的力学性能和耐磨性得到显著改善,加入SF的复合材料的冲击断裂面出现明显的纤维拔出形态,材料的磨损面呈现粘着磨损特征形态.     

碳纤维表面处理对2D碳/碳复合材料弯曲性能的影响

为改善纤维与基体的界面结合状态及提高碳/碳复合材料性能,采用1700℃惰性气体保护、2200℃惰性气体保护、400℃空气氧化三种表面处理方法对碳纤维进行了表面处理.结果表明,经过2200℃处理后的纤维表面比较粗糙,有很多沟槽,制备的碳/碳复合材料中纤维与基体结合紧密,弯曲强度比未经表面处理的纤维制备的碳/碳复合材料弯曲强度提高75%;经过400℃处理后的纤维表面凹坑、凸起较纤维未处理前增多,制备的碳/碳复合材料中纤维与基体结合强度适中,其弯曲强度比未经表面处理的纤维制备的碳/碳复合材料弯曲强度提高43%;而经过1700℃处理的纤维表面比较光滑,纤维与基体结合弱,弯曲强度比未经表面处理的纤维制备的碳/碳复合材料的弯曲强度低.     

棉秆皮预处理对棉秆皮纤维/PP复合材料力学性能的影响研究

用碱处理、蒸汽闪爆、蒸汽闪爆结合碱处理这3种预处理方法制备的棉秆皮纤维作为增强体,通过热压成型制备了棉秆皮纤维/聚丙烯复合材料。首先优化了制备该复合材料的棉秆皮纤维长度、热压温度、压力以及时间等工艺参数,并以此优化工艺为基础,研究了3种预处理方法制备的棉秆皮纤维对复合材料拉伸、弯曲、冲击性能以及微观形貌的影响。结果表明:在棉秆皮纤维长度为8cm、热压温度170℃、热压压力3MPa、热压时间4min条件下制备的复合材料性能较优;在3种预处理方法中,采用蒸汽闪爆与碱预处理棉秆皮纤维制备的复合材料性能最优,复合材料拉伸强度为36.290MPa、拉伸模量为4557.40MPa、弯曲强度为63.31MPa、弯曲模量为4780.00MPa、冲击强度为485.0J/m。     

碳纤维增强空心玻璃微珠/环氧树脂复合材料的力学性能

制备了纤维长度为1 mm和2 mm的碳纤维增强空心玻璃微珠/环氧树脂复合材料,其纤维质量比分别为0.2%、0.5%、1%和3%。对材料进行三点弯曲实验和压缩实验,研究了纤维长度和纤维质量比对其弯曲强度和弯曲弹性模量、压缩强度和压缩弹性模量等力学性能的影响。结果表明,添加两种长度的碳纤维都能明显提高复合材料的弯曲和压缩力学性能。随着碳纤维质量比的增大复合材料的弯曲强度和压缩强度呈先增大后减小的趋势,当碳纤维的质量比为0.5%时达到最大值,随后则随纤维含量的增大而逐渐降低。当碳纤维的长度为1 mm质量比为0.5%时,复合材料试件的弯曲强度和压缩强度比未添加纤维时分别提高198%和110%。碳纤维的长度为1 mm时纤维含量的变化对复合材料的弯曲强度、压缩强度和压缩弹性模量有较大的影响,但是当纤维长度为2 mm时纤维含量的变化对弯曲强度和压缩强度的影响不大。     

苎麻纤维表面处理对其复合材料性能的影响

在不同处理时间和功率的条件下,对苎麻纤维表面进行冷等离子体处理。通过分析纤维表面能以及纤维拉伸强度的变化,选取了3组处理纤维与未处理纤维作为复合材料的增强纤维,并且运用模压工艺制备苎麻纤维增强复合材料。经过扫描电镜分析、弯曲强度和剪切强度测试以及单纤维断裂实验,探究了冷等离子体处理对苎麻纤维表面性能及其复合材料性能的影响。结果表明:冷等离子体处理去除了苎麻纤维表面的胶质和杂质,提升了纤维与环氧树脂的粘附功。随着处理时间与功率的增加,复合材料板的力学性能随之提升。与未处理纤维复合材料相比,当处理条件为3min、200W时,复合材料的弯曲强度与剪切强度分别提升了37.0%和30.5%。     

废印刷电路板非金属粉填充聚丙烯的实验

采用熔融共混方法制备了废印刷电路板非金属粉/聚丙烯复合材料,并通过非金属粉润湿性能和缺口冲击断面形貌观察,分析研究了非金属粉添加对聚丙烯复合材料力学性能的影响。结果表明,非金属粉可以同时改善非金属粉/聚丙烯复合材料的拉伸、弯曲、低温冲击性能,但室温冲击性能降低;其中拉伸强度、拉伸模量、弯曲强度、弯曲模量、低温冲击强度最大增幅分别为16.3%、41.5%、63.5%、100%、45.7%;废印刷电路板非金属粉可作为聚丙烯的增强增韧填料。     

混杂比对碳纤维-玄武岩纤维混杂增强环氧树脂基复合材料弯曲性能的影响

将玄武岩纤维置于混杂铺层的压缩侧,研究了碳纤维-玄武岩纤维混杂增强环氧树脂基复合材料的弯曲性能及混杂比对其弯曲性能的影响。通过对试样进行三点弯曲试验得到了材料的弯曲性能,并通过扫描电子显微镜观察材料的失效模式。与纯碳纤维增强环氧树脂基复合材料相比,当混杂比为16.7%和33.3%时,混杂复合材料的弯曲强度明显提升,弯曲强度分别提高12.4%和15.2%,但是其弯曲模量随着混杂比的提升而降低。混杂后的材料及玄武岩纤维增强环氧树脂基复合材料的失效位移都高于碳纤维增强环氧树脂基复合材料,断裂韧性明显提升。从侧面观察可以发现不同铺层在压缩侧、拉伸侧和中间层有不同的失效形式。      

植物纤维增强PS木塑复合材料的性能研究

以木纤维、竹纤维和聚苯乙烯为主要原料,加入偶联剂、润滑剂、增塑剂等加工助剂,经挤出注塑制备聚苯乙烯/木纤维复合材料。研究了植物纤维种类和添加质量分数、偶联剂KH-550添加质量分数对PS木塑复合材料力学性能的影响。结果表明：木纤维和偶联剂的加入都使复合材料的力学性能呈先增大后减小的趋势。当木纤维添加质量分数为25%,偶联剂KH-550添加质量为木纤维添加质量的1.5%时,复合材料具有最大的拉伸强度、弯曲强度和断裂伸长率,分别为30.2MPa,86MPa和8.74%,缺口冲击强度随木纤维添加质量分数的增加而减小。木纤维和竹纤维填充的两种复合材料的拉伸强度、弯曲强度和冲击强度相差不大。     

缝合复合材料单向板的拉压性能

缝合复合材料改善了层合复合材料易分层的缺陷,其力学性能研究具有重要意义。建立缝合复合材料单向板的三维有限元分析模型,考虑了缝合针脚造成的纤维面内和面外弯曲,分析了纤维弯曲对拉伸和压缩性能的影响。结果表明,模型能很好预测缝合单向板拉伸和压缩性能,同时考虑纤维面内和面外弯曲对预测更为有利,纤维面内和面外弯曲是影响强度的主要因素,纤维面内弯曲对模量影响较大,而纤维面外弯曲对模量的影响可以忽略不计。     

The mechanical interlocking and wetting at the interface between argon plasma treated UHMPE fiber and vinylester resin

The ultra high modulus polyethylene (UHMPE) fiber was treated with argon plasma in order to improve the interfacial adhesion of UHMPE fiber/vinylester composites. Argon plasma treatment of the UHMPE fiber introduces micro-pittings and roughness onto the UHMPE fiber surface. These micro-pittings and surface roughness increase the interfacial adhesion of the UHMPE fiber/vinylester composites through the mechanical interlocking between the UHMPE fiber and vinylester resin. Argon plasma treatment also changes the UHMPE fiber surface into chemically more inert state in comparison with the control UHMPE fiber surface. These chemical changes decrease the efficiency of the mechanical interlocking as the inert surface makes the wetting of the UHMPE fiber by the vinylester resin difficult. In this study, the mechanical interlocking through the micro-pittings is known to play a key role in improving the interfacial adhesion of UHMPE fiber/vinylester composites by the argon plasma treatment. However, the complete wetting of the UHMPE fiber by the vinylester resin is known to be an important requirement for the effective mechanical interlocking between the UHMPE fiber and vinylester resin.     

The effect of polybutadiene interlayer on interfacial adhesion and impact properties in oxygen-plasma-treated UHMPE fiber/epoxy composites

In order to improve the interfacial adhesion and impact properties of ultra-high modulus polyethylene (UHMPE) fiber/epoxy composites at the same time, the fiber coating technique was combined with the oxygen plasma treatment. The UHMPE fiber was treated with oxygen plasma and thin polybutadiene (PB) coating was introduced. PB coating decreased the interfacial adhesion and increased the impact property of the oxygen-plasma-treated UHMPE fiber/epoxy composites. However, oxygen-plasma-treated and PB-coated UHMPE fiber/epoxy composites show improved interfacial adhesion, flexural properties and impact property in comparison with the untreated control UHMPE fiber/epoxy composites. Oxygen plasma treatment introduces micro-pittings on the UHMPE fiber surface. These micro-pittings improved interfacial adhesion and flexural properties and decreased impact properties through mechanical interlocking. Thin PB coating cannot exclude this mechanical interlocking effect completely and there are imperfect wetted UHMPE fiber surface regions in which effect mechanical interlocking can occur. Stress transfer through the viscous PB interlayer also contributes to the interfacial adhesion and flexural properties of PB-coated UHMPE fiber/epoxy composites. The impact property of PB-coated UHMPE fiber/epoxy composites is due to low modulus PB interlayer.     

聚乙烯自增强复合材料的制备及力学性能

采用超高模聚乙烯纤维分别增强高密度聚乙烯和低密度聚乙烯基体，在不同的工艺条件下制备样品，对样品进行纵横向拉伸和剪切性能的测试，探讨聚乙烯自增强复合材料界面性能。     

碳纤维单丝带对酚醛树脂基复合材料力学性能的增强作用

将连续碳纤维束用空气梳分散成单丝状的长带, 经60 %硝酸进行表面氧化处理后用作酚醛树脂复合材料的增强材料。用红外光谱、扫描电镜等表征复合材料的微观结构, 通过力学性能测定发现, 与连续的碳纤维束增强相比, 单丝带增强复合材料的弯曲强度提高了1 倍, 层间剪切强度( ILSS) 提高了2 倍, 但冲击强度有所降低。结果表明, 碳纤维经过表面氧化和丝束分散的处理后, 能有效地提高其与复合材料中树脂基体的结合性能。      

Factors affecting the interfacial adhesion of ultrahigh-modulus polyethylene fibre–vinylester composites using gas plasma treatment

The interfacial adhesion of ultrahigh-modulus polyethylene (UHMPE) fibre–vinylester composites was improved by the oxygen plasma treatment of the UHMPE fibre. The chemical functional group formations on the UHMPE fibre surface by oxygen plasma treatment were analysed using diffuse reflectance Fourier transform infrared spectroscopy and the morphological changes of the UHMPE fibre surface by plasma etching were observed by scanning electron microscopy. The wettability enhancement by the chemical functional group formation and the mechanical interlocking due to the micropits were important factors in improving the interfacial adhesion of the UHMPE fibre–vinylester composites by oxygen plasma treatment. In order to investigate the relative importance of the two factors, wettability enhancement and mechanical interlocking, in the improved interfacial adhesion of the UHMPE fibre–vinylester composites, nitrogen plasma treatment was also performed. Nitrogen plasma treatment of the UHMPE fibre was proved to be effective in the formation of the micropittings and ineffective in the chemical functional group formation in comparison with the oxygen plasma treatment. The interlaminar shear strengths of the nitrogen-plasma-treated UHMPE fibre–vinylester composites showed almost the same value as those of the oxygen-plasma-treated UHMPE fibre–vinylester composites. The wettability enhancement and mechanical interlocking are important in the improvement of interfacial adhesion of UHMPE fibre–vinylester composites by plasma treatment and mechanical interlocking seems to be more important.     

Influence of CVI treatment of carbon fibers on the electromagnetic interference of CFRC composites

Short carbon fibers were treated at temperatures around 1100 °C in a furnace through chemical vapor infiltration technology. The fiber surface was observed by scanning electron microscopy. The reflectivity of electromagnetic radiation by the composites that were reinforced by surface-treated carbon fibers and by as-received ones was measured in the frequency range of 8.0–18.0 GHz. The reflectivity for different carbon fiber contents of 0.2%, 0.4%, 0.6% and 1.0 wt% was investigated. Results showed that the reflectivity of the composites that were reinforced by untreated carbon fibers tended to increase with the increasing fiber contents. The minimum reflectivity was −19.3 dB, far less than −10 dB, when the fiber content was 0.4% and there were wave-absorbing properties. However, after surface treatment, the minimum reflectivity was −8.1 dB for the same fiber content of 0.4%, indicating significant wave-reflecting properties. The achieved reflectivity values after surface treatment were generally greater than those without treatment.     

Special manufacturing and characteristics of basalt fiber reinforced hybrid polypropylene composites: Mechanical properties and acoustic emission study

Basalt fiber reinforced, polypropylene matrix hybrid composites were manufactured in the process of carding, needle-punching and pressing. Hemp, glass and carbon fibers were applied besides basalt fiber in these composites. In order to achieve a sufficient interfacial adhesion, the fibers were treated with the reaction mixture of maleic acid anhydride and sunflower oil. The hybrid effect in these composites was examined as a function of fiber content and fiber combination. The strength properties of hybrid composites improved owing to surface treatment and this was proven by mechanical tests and microscopic analysis, as well. Acoustic emission methods revealed that there is a correlation between the physical parameters of sound waves that occurred during failure and the mechanical properties.     

碳纤维增强尼龙1010的力学性能及其对摩擦磨损的影响

用碳纤维填充尼龙1010制备了碳纤维增强尼龙复合材料,并对碳纤维增强尼龙复合材料的力学性能和摩擦学性能进行了实验研究。力学实验结果表明:碳纤维增强使尼龙复合材料的拉伸强度、表面硬度增大,碳纤维增强尼龙材料的拉伸强度在20%碳纤维含量时达到最大值;碳纤维表面处理对尼龙复合材料的拉伸强度有很大影响,碳纤维表面氧化处理提高了碳纤维增强尼龙复合材料的拉伸强度。摩擦磨损实验表明:碳纤维增强尼龙复合材料的摩擦系数和磨损率与其拉伸强度和硬度有密切关系。随着拉伸强度和硬度的提高,尼龙复合材料摩擦系数和磨损率降低;摩擦系数和磨损率与拉伸强度具有反比关系,与材料硬度具有二次方程关系,与碳纤维填充量之间存在负指数变化规律。      

聚乙烯自增强复合材料的热分析

采用超高模聚乙烯纤维分别增强高密度聚乙烯和低密度聚乙烯基体。对不同的工艺条件下制成的样品用差示扫描量热法(DSC)进行分析。探讨聚乙烯自增强复合材料界面形成机理和界面性能．