改性苎麻布增强PP复合材料性能的研究

以聚丙烯（PP）膜作为基体材料,苎麻布作为增强体,制备出苎麻增强PP复合材料。选取五层平纹布和PP膜进行层合热压,制备出苎麻增强PP热塑性复合材料薄板,分析了影响扳材拉伸性能的因素。结果表明,苎麻织物经过碱处理后,其层压材料的拉伸性能得到明显的改善,拉伸强度比未处理前的层压材料增加了48．4％;苎麻织物经过硅烷偶联刹KH-550、A-151预处理后,层压材料的拉伸强度分别提高了42．3％和69．4％。     

洋麻纤维的表面改性及其在聚丙烯基复合材料中的应用

采用碱处理、偶联剂处理以及碱–偶联剂复合处理对洋麻纤维进行表面改性,然后将其与聚丙烯(PP)纤维复合,采用非织造–模压工艺制备了PP/洋麻纤维复合材料。研究了上述3种表面改性方法对洋麻纤维强度及其复合材料弯曲与剪切性能的影响,并采用扫描电子显微镜(SEM)研究了洋麻纤维表面改性前后的形貌变化及其与PP基体之间的界面结合状况。结果表明,表面改性后洋麻纤维的拉伸强度均降低,但复合材料的弯曲强度及层间剪切强度均提高,表明这3种改性方法均提高了洋麻纤维与PP之间的界面结合强度;碱处理可去除纤维表面的果胶成分,使纤维束变得松散,使复合材料的弯曲强度及层间剪切强度分别较未表面改性时提高了21%和169%,但弯曲弹性模量降低了21%;偶联剂处理则使复合材料的弯曲强度,弯曲弹性模量和层间剪切强度较未表面改性时提高了23%,7%和160%;碱–偶联剂复合处理兼顾了碱处理和偶联剂处理的优点,使复合材料弯曲强度、弯曲弹性模量和层间剪切强度分别较未表面改性时提高了26%,18%和572%,综合性能最佳。SEM结果表明,碱–偶联剂复合处理后,复合材料中纤维与树脂之间的界面结合较好。     

PU/OMMT纳米复合材料的制备与性能研究

采用一步法和预聚体法制备聚氨酯（PU）／有机蒙脱土（OMMT）纳米复合材料，研究分散方式对OMMT层间距以及复合材料制备方法和OMMT用量对纳米复合材料拉伸性能的影响。结果表明，采用高速剪切分散法和超声波分散法均可使聚四氢呋喃醚二醇分子链进入OMMT片层间，增大其层间距；预聚体法PU／OMMT纳米复合材料拉伸性能优于一步法复合材料；与PU弹性体相比，当OMMT用量为0．5份时，一步法复合材料的强度和韧性均提高。牌号为DKIN的OMMT用量为7份时。复合材料的拉伸强度提高54％，拉断伸长率提高19．4％，增幅最大。     

缝合技术在长竹纤维复合材料制备中的应用研究

采用缝合技术制备了长竹纤维单向复合材料,研究了缝线种类和缝合间距对于复合材料的拉伸、弯曲和层间剪切性能的影响。结果表明,随着缝合间距的增加,单向连续竹原纤维/不饱和聚酯树脂(UP)复合材料的拉伸、弯曲、剪切性能基本呈先上升后下降的趋势,且当缝合间距为3cm时,复合材料性能最好。芳纶缝线与涤纶缝线制备的复合材料相比,拉伸强度、拉伸模量分别高7.32%、12.09%,弯曲强度、弯曲模量分别高4.99%、3.47%,剪切强度低8.47%,复合材料总体性能相差不大。     

前处理对亚麻增强热塑性复合材料力学性能的影响

将增强体亚麻纱线进行碱处理和偶联剂处理，再制成pp／亚麻包覆纱后进行平纹布织造，用层合热压法制成复合材料。处理后的亚麻纱线性能发生了变化；对最终复合材料进行了拉伸性能和声发射的测试，结果表明前处理后的复合材料界面粘结性提高，拉伸强度提高，弹性模量减小，其中碱处理的作用更大。     

超临界CO2对碳纤维环氧树脂的界面性能的改善

为提高碳纤维/环氧树脂复合材料的界面结合性能,采用超临界CO2对碳纤维表面进行处理.结果表明:在处理后碳纤维的单丝拉伸强度下降2.81％,碳纤维/环氧树脂界面剪切强度和层间剪切强度在处理后分别提高25.19％和17.11％.通过对碳纤维原子力显微镜(AFM)观察,经过处理的碳纤维表面粗糙度增加明显,同时对复合材料层间剪切断口端面用扫描电子显微镜(SEM)观察,经过超临界CO2处理后的碳纤维与环氧树脂的复合性能得到改善.     

丙烯酸酯类聚氨酯/蛭石纳米复合材料的制备与性能研究

分别采用十六烷基三甲基溴化铵（CTAB）、CTAB与聚乙二醇400（PEG400）的复合体系对蛭石进行有机化处理,然后用有机改性的蛭石、甲基丙烯酸田一羟乙酯、异佛尔酮二异氰酸酯、PEG400进行复合插层反应,制得丙烯酸酯类聚氨酯／蛭石纳米复合材料,并对有机处理前后的蛭石结构和复合材料的性能进行了表征。结果表明,经有机处理后,蛭石层间距明显增大,用CTAB／PEG400复合体系做插层剂时,蛭石的层间距较大;当有机蛭石质量分数为1．00％时,复合材料的综合性能较佳,拉伸强度为25．09MPa,拉伸断裂伸长率为30．02％,冲击强度为40．48kJ／m^2．玻璃化转变温度为85．51℃,分别较纯丙烯酸酯类聚氨酯提高了12．5％、36．9％、446．3％、6．86℃。     

电化学氧化处理对碳纤维及EP复合材料性能的影响

利用电化学氧化法对碳纤维（CF）进行表面改性处理,并将改性CF用于改性环氧树脂（EP）,研究了CF处理前后纤维复丝拉伸强度和EP／CF复合材料的力学性能。结果表明,氧化处理改善了CF与基体的粘结性;经电化学氧化处理后CF的表面羟基含量提高39．96％,羧基／酯基含量提高141．06％,活性碳原子数增加34．28％;随着氧化电流密度的增加,CF复丝的拉伸强度和复合材料的层间剪切强度均呈现先增大后减小的变化趋势,当电流密度为0．2A／m^2时,复合材料的层间剪切强度提高31．70％。     

三维正交机织玄武岩/芳纶混编复合材料的拉伸和剪切性能研究

本文设计和制作了两种混杂模式的三维正交机织玄武岩/芳纶混编复合材料,分别是层间混杂和层内混杂模式。对其拉伸性能和剪切性能进行了测试和分析,结果表明,层内混杂复合材料的拉伸性能和剪切性能比层间混杂复合材料的好,层内混杂复合材料的归一化强度和归一化模量分别比层间混杂复合材料的高22.12%和16.9%,层内混杂复合材料的剪切强度和剪切模量分别比层间混杂复合材料的高19.61%和26.03%;对于层间混杂复合材料,纬向的归一化强度比经向的高4.06%,但厚度方向上纱线的存在和织造工艺中经纱预加张力的影响,使纬向的归一化模量比经向的降低11.44%。     

偶联剂处理玻纤改性热塑性聚酰亚胺

分别选用KH550、KH560、KH570三种有机硅烷偶联剂处理无碱玻纤粉（GF）,采用热模压成型技术制备玻纤增强聚酰亚胺复合材料,对复合材料的力学性能进行了分析和研究。结果表明：以KH550处理30％玻纤得到的复合材料力学性能最好,当其用量为GF质量的0．5％时,拉伸强度提高了35％,弹性模量提高了21．8％,弯曲强度提高了42．1％,冲击强度提高了52．5％。SEM显示KH550处理GF与聚酰亚胺基体之间形成了良好的界面,界面层起到很好的应力传递作用,达到良好的增强、增韧效果。     

Comparison of tensile and compressive characteristics of intra/interply hybrid laminates reinforced high‐density flexible foam composites

The current study focused on fabrication and mechanical evaluation of intra/interply hybrid laminates – reinforced high‐density flexible foam composites. The effects of composite thickness and expansion factor on the tensile and compressive characterization of the hybrid ‐ laminated composites were experimentally investigated. Double face sheets were made of high‐strength intra/interply hybrid laminates containing recycled Kevlar nonwovens and glass woven fabric. The results revealed that the hybrid laminates face sheet apparently promoted the tensile strength and tear resistance of the high ‐ density flexible polyurethane foam. Tearing resistance in perpendicular direction exceeded more than twice the value in parallel direction. In terms of dynamic cushioning properties, cushioning force increased with the increase in composite thickness and the decrease in expansion factor , whereas the cushioning capacity loss, however, showed a different trend with the variation of the parameters. Most samples buffered more than 95% incident force under dynamic loading. Composite thickness and expansion factor exhibited significant influence on compression and indentation properties, including hardness, initial hardness factor , and indentation modulus. Except the composites with 10 mm thickness, the intra/interply hybrid laminated composites exhibited hysteresis loss of indentation force deflection ranging from approximately 30 to 38%, which was due to the fiber and thermal bonding point failure of hybrid laminates as unrecoverable damage. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41438.     

Tear resistance of sparsely reinforced elastomer sheets

A family of elastomer composites has been developed which has outstanding tear resistance, and good tensile strength and elongation to failure as measured in a standard tensile test. These composites constitute a family in that they all are sparsely reinforced by a fishnet-like webbing of reinforcement. The members of the family differ in that the reinforcements can be as flexible as soft polyurethane rod or as stiff as carbon fiber with 3000 strands per fiber. All these composites produce outstanding tear strength and an increase in the elongation to failure in an ASTM Die-C type of tear test. The intersections of the polyurethane rod reinforcements prove to be effective crack arrestors.     

Polybutadiene adhesive compositions

This paper deals with the development of adhesives that are useful for preparing flexible laminates. The adhesive compositions are based on the chemistry of 1,2-polybutadiene polymers and their reactions via chain extension and epoxidation. The resulting materials can be suitably formulated to produce resins that can be used to impregnate fibrous reinforcements which can be B staged; when laminated to copper, these materials give products with good peel strength, solder resistance, tear strength, and flame resistance. These adhesives can also be used to bond polyimide and polyester film to themselves and to copper. Typical properties of selected laminates include peel strength values of 8 lb/in. width, tear strength of 1–2 lb, oxygen index from 29 to 37, and excellent solder resistance.     

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.     

生物可降解山麻杆韧皮纤维增强PBS复合材料的性能研究

以山麻杆韧皮纤维为增强体,其与PBS颗粒按质量比20∶80模压成型制备了4种板材,探讨了表面处理对纤维微观结构与物理性能的影响,分析比较了板材力学性能及生物降解性。结果表明, 采用物理化学相结合方法预处理后,表面依然存留一定量的果胶等物质;预处理纤维进一步碱处理后表面出现“S”形凹槽,预处理纤维进一步偶联剂处理后表面凹槽连续性好、深度深;碱处理、偶联剂处理后纤维拉伸强度分别提高5.08 %和降低3.58 %;相比纯PBS,偶联剂处理后纤维复合材料拉伸强度与弯曲强度各提高48.32 %和25.97 %,拉伸模量与弯曲模量各提高146.45 %和128.30 %;3种纤维复合材料生物可降解性变化趋势一致,但偶联剂处理后的材料失重率变化幅度最小。     

表面处理对剑麻纤维布/不饱和树脂材料性能影响

采用碱、高锰酸钾及热对剑麻纤维布进行了表面处理,并由真空辅助树脂传递模塑成型(VARTM)工艺制备了剑麻纤维布增强不饱和聚酯树脂复合材料。通过对复合材料的力学性能及吸水性的测试,研究了不同剑麻纤维布表面处理对其不饱和聚酯树脂复合材料性能的影响。结果表明:经过碱处理,复合材料的拉伸、弯曲,冲击强度提高最大,可分别提高26.5%,16.5%和22.6%,吸水率降低了47.5%。对剑麻纤维布进行表面处理可使复合材料的界面性能得到改善,力学性能提高,吸水性降低。     

Effect of alkali treatment on properties of unidirectional isora fibre reinforced epoxy composites

Abstract

Unidirectional isora fibre reinforced epoxy composites were prepared by compression moulding. Isora is a natural bast fibre separated from Helicteres isora plant by retting process. The effect of alkali treatment on the properties of the fibre was studied by scanning electron microscopy (SEM), IR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Mechanical properties such as tensile strength, Young's modulus, flexural strength, flexural modulus and impact strength of the composites containing untreated and alkali treated fibres have been studied as a function of fibre loading. The optimum fibre loading for tensile properties of the untreated fibre composite was found to be 49% by volume and for flexural properties the loading was optimised at ～45%. Impact strength of the composite increased with increase in fibre loading and remained constant at a fibre loading of 54·5%. Alkali treated fibre composite showed improved thermal and mechanical properties compared to untreated fibre composite. From dynamic mechanical analysis (DMA) studies it was observed that the alkali treated fibre composites have higher E' and low tan δ maximum values compared to untreated fibre composites. From swelling studies in methyl ethyl ketone it was observed that the mole percentage of uptake of the solvent by the treated fibre composites is less than that by the untreated fibre composites. From these results it can be concluded that in composites containing alkalised fibres there is enhanced interfacial adhesion between the fibre and the matrix leading to better properties, compared to untreated fibre composites.     

Effects of Filler Loading and Different Preparation Methods on Properties of Cassava Starch/Natural Rubber Composites

Cassava starch-filled natural rubber (NR) composites were prepared by using direct blending and co-coagulation method. The effects of two different method and cassava starch loading on morphology, mechanical properties and thermal properties of cassava starch/NR composites were studied. X-ray diffraction results and scanning electron microscopy images proved that co-coagulation method promotes better dispersion of cassava starch than direct blending method. The composites prepared by co-coagulation method exhibited higher values of tensile strength, tear strength, hardness, and thermal stability. The optimum value of tensile strength and tear strength of cassava starch/NR composites were achieved at a 10 phr cassava starch loading.     

有机蒙脱土增强聚氯乙烯手套材料的制备与表征

通过在乳液聚氯乙烯（PVC）中添加有机蒙脱土（OMMT）来研究OMMT对其各项性能的影响。结果表明：OMMT对乳液PVC／邻苯二甲酸二辛酯（DOP）／OMMT纳米复合材料的力学性能有一定的改善效果;对复合材料的抗增塑剂迁移效果明显;在耐酸和耐碱试验中,未添加OMMT的复合材料的拉伸强度和撕裂强度分别降低了7．3％、5．i％和5．5％、13．3％,而添加3份OMMT后,仅仅降低了2．5％、2．6％和1．5％、4．2％,效果显著。