亚麻增强热塑性树脂复合材料板材的研究与应用

以亚麻纤维为增强体,与聚丙烯(PP)纤维按一定比例进行混合,然后制备加捻纱及PP长丝包覆的包覆纱,并利用机织工艺织成二维机织布作为复合材料的预制铺层.采用层合热压方法制备PP/亚麻纤维复合材料板材.通过对板材弯曲性能的测试及分析,研究了制备工艺、纱线结构及亚麻纤维含量等因素对复合材料弯曲性能的影响.     

制备工艺对亚麻增强聚丙烯复合材料拉伸性能的影响

以亚麻纤维为增强体,与聚丙烯（PP）长丝进行丝束级共混,形成PP包覆亚麻的纱线结构,利用机织工艺织成二维机织布,作为复合材料的预制件。采用层合热压方法制备PP／亚麻复合材料板材。通过对板材拉伸性能测试及扫描电镜（SEM）拉伸断口形貌分析,研究了不同纤维体积分数、织造密度及织造组织等因素对复合材料拉伸性能的影响。结果表明,在选取最优热压温度与压力的条件下,纤维体积分数为50％的板材性能最优;经向密度相同时,拉伸性能随着纬向密度的增加而提高;经、纬向密度均相同时,斜纹3／1组织的板材性能最优,纬向最大拉伸强度可达92．42 MPa。     

亚麻/聚丙烯复合材料的成型工艺和拉伸性能研究

本文探讨了亚麻/聚丙烯纤维复合材料的制备工艺和拉伸性能.对亚麻纤维含量分别为30%、40%、50%、60%、70%的复合材料进行比较,分析增强纤维含量对复合材料拉伸性能的影响;对模压温度分别为150℃、160℃、170℃、180℃、190℃的复合材料进行比较,分析模压温度对复合材料拉伸性能的影响,最后确定模压温度及亚麻/聚丙烯纤维的混合比.     

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。     

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％。     

亚麻针织物增强聚丙烯基热塑性复合材料的制备

本文以天然亚麻纤维为增强纤维,聚丙烯为基体,编织形成不同纤维体积比、不同结构的亚麻/聚丙烯针织物预制件,并经过热压复合制备形成一定的亚麻/聚丙烯针织物增强热塑性绿色环保的民用纺织复合材料。通过对增强纤维及基体材料性能的分析,以及对预制件和复合材料板材结构参数和制备工艺的设计和分析,得到较优的产品结构和制备工艺,认为亚麻/聚丙烯针织结构预制件的编织工序简单且效率高,并可直接热压复合,降低了复合材料的制备成本。4层、6层预制件热压过程中施加的最大压力为10MPa时最优,8层预制件热压过程中施加的最大压力为15MPa时最优。     

聚丙烯/亚麻复合材料的制备及其冲击性能的研究

以亚麻纱线作为增强体与聚丙烯(PP)纤维按不同质量比进行混合,制备出PP长丝包覆的包覆纱,利用机织工艺织成二维机织布作为复合材料的预制铺层,采用热压法进行层合热压,制备出亚麻增强PP复合材料板材。通过对板材冲击性能的测试及分析,研究了制备工艺、纱线结构及纤维含量等因素对复合材料冲击性能的影响。结果表明,当亚麻纱线质量分数为68%时板材的冲击性能最好;"三明治"(纯亚麻织物与聚丙烯纤维毡交替铺层)法制备的板材表现出较好的冲击性能;0°/0°板材在受到冲击时比0°/90°板材吸收的冲击能更多,表现出较好的耐冲击性。     

热塑性复合材料板材拉伸强度近似计算

针对热塑性复合材料拉伸强度,以亚麻增强聚丙烯机织层合复合材料板材为例,结合理论分析,首先对其进行理想条件下的强度计算,通过推导得到理想状况下的强度理论计算公式,进而结合具体试验条件,在此理论计算公式基础上引进板材经、纬向纤维伸直系数aj、aw作为修正系数进行修正。利用多项式拟合,最终得出符合试验条件下的强度近似计算公式及拟合曲线。     

制备工艺对亚麻增强热塑性复合材料拉伸力学性能的影响

将增强体亚麻纱线和基体丙纶复丝制成pp/亚麻包覆纱后,进行织造,织物用层合热压法制成复合材料.制备工艺中,包覆纱法对复合材料的拉伸强度最好;麻含量50%的复合材料的拉伸强度达到最佳;当纬纱密度相同时,随着经纱密度的增大经向的拉伸强力和拉伸弹性模量也随之增大,而纬向的却随之减小,当经纱密度相同时,随着纬纱密度的增大,经向的拉伸强力和拉伸弹性模量随之减小,纬向的随之增大.     

聚丙烯/低温可膨胀石墨阻燃复合材料的性能研究

采用低温可膨胀石墨(LTEG)作为阻燃剂,制备了聚丙烯基阻燃复合材料。研究了聚丙烯/LTEG阻燃复合材料的阻燃性能、热性能、剩炭结构和力学性能。研究发现,采用LTEG为阻燃剂的聚丙烯基阻燃复合材料具有优异的阻燃性能,LTEG质量分数为15%时,复合材料氧指数已达27%。聚丙烯/LTEG复合材料的热失重温度低,在燃烧过程中并没有形成理想致密的炭层。LTEG对聚丙烯具有增强作用,随着其用量的增加,复合材料的拉伸强度增加,断裂伸长率不断下降。     

仿麻复合竹节纱的开发

通过在日本村田公司Ｍ－３３（Ｈ）花色变形机上加工仿麻复合竹节纱，探讨了仿麻复合竹节纱的复合假捻加工技术。加工仿麻复合竹节纱要求原料的单丝纤度在１．１～５．６ｄｔｅｘ，合理选择捻度，超喂率一般选择在２０％～４０％，加热器温度应随原料组合的变更而选择。     

Influence of textile treatment on mechanical and sorption properties of flax/epoxy composites

The aim of the present work is to study the effect of conventional textile treatments of woven flax on the mechanical properties and the water sorption of flax/epoxy composites. The flax fabrics are standard 2/2 twills. Various treatments are carried out on fabric such as mercerization, bleaching, and leaching for long fibers or on yarn such as leaching for short fibers. A model, based on a modified rule of mixture applied to composite reinforced with woven fabric, is developed to include the effect of fiber and porosity volume fractions on composite stiffness and strength. Most treatments improve tensile stiffness and strength of flax/epoxy composite and reduce composite water sorption. We prove by X‐ray fluorescence analysis, thermogravimetric analysis, and tensile tests of dry fabric that it is due to an improvement in the interfacial bonding between fibers and matrix. The best performances are achieved with bleaching and mercerization treatment. The weakest performances are obtained with the composites made with leached yarns. POLYM. COMPOS., 34:1761–1773, 2013. © 2013 Society of Plastics Engineers     

Diffusion and Permeation of Gases in Fiber-Reinforced Composites

Abstract

The presence of filler in a matrix phase greatly alters and also complicates the diffusion process, making experimental data very difficult to handle analytically. In this study both diffusion and permeability data were obtained in unfilled cellulose acetate films and cellulose acetate films filled with cheese cloth. Cheese cloth being highly permeable, the permeabilities and diffusivities of gases in the filled films are greater than in unfilled films due to reduced effective film thickness for molecular diffusion. A mathematical model has been developed which considers molecular diffusion to occur in that part of the film having no filler, while diffusion through the low-resistance cheese cloth is approximated by convective flow controlled only by the pressure gradient across the thickness of the cheese cloth yarn. The mathematical model predicts permeability values somewhat lower than experiment at low flow rates, but agrees well with experimental permeabilities at higher rates. The poor agreement between theoretical and experimental diffusivities is attributed mainly to errors involving the measurement of time lags. Morphological studies of the composite surfaces and cheese cloth filaments show that the cellulose acetate did not penetrate into the cheese cloth yarn which essentially retains its porous structure in the composite.     

异染、异收缩特种混纤丝的开发与生产

采用具有不同染色性能的PET和CDP切片,在SP23纺丝机和M—402拉伸机上,通过对纺丝、拉伸工艺的合理选择,可制得具有异染和异收缩特性的特种混纤网络丝.该丝加工成平纹织物,经阳离子染料染色后,布面具有独特风格.     

包覆纱工艺对亚麻增强预型件的麻纤维分数和拉伸性能影响

基于增强体亚麻纱线和热塑性丙纶长丝,通过包覆纱纺纱工艺研究了包覆纱纺织预型件及其复合材料的加工性能.通过对中空锭捻度和空心锭转速的单因子研究分析,研究表明,中空锭捻度和空心锭转速是影响包覆纱预型件的纤维体积分数和拉伸性能的两个主要因素.并利用二次通用旋转设计的方法,建立回归分析实验模型,来优化组合中空锭捻度和空心锭转速的参数以得到结构均匀的包缠纱线和预型件.结果表明,该包缠纱适合于生产均一的预混料,可用于形成纺织结构预型件及复合材料.     

Effects of Carbon Yarn Size on the Mechanical Properties of Plain Woven C/SiC Composites

The effects of yarn size on the mechanical properties of silicon carbide composites reinforced with a plain woven carbon cloth with two sizes of yarns (1 and 3 k) were investigated. The experimental results show that the composite fabricated with 1 k yarns exhibits greater stiffness and strength than the composite fabricated with 3 k yarns. Microstructural observations revealed the existence of matrix microcracks in both the composites under the as-processed condition due to the large difference of thermal expansion between the fibers and the matrix, which are more severe for the composite with 3 k yarns. The fractured surfaces of the composite with 1 k yarns showed extensive fiber pull-out in contrast to the yarn pull-out in the composite with 3 k yarns. The larger interyarn and intrayarn voids due to difficulties of matrix infiltration in the composite with 3 k yarns represent the primary contribution to the diminished mechanical properties. Unequal yarn sizes give rise to different yarn waviness, which may be another source of difference in the mechanical properties of composites.     

不同预型件工艺对亚麻/聚丙烯热塑性复合材料力学性能的影响

采用交织混编法和包覆纱法加工成型亚麻聚丙烯热塑性预型件及其复合材料,比较了这两种成型方法对预制件及其复合材料的浸渍效果、拉伸性能和剥离性能的影响。结果表明,包覆纱法制备的预型件及其复合材料的浸渍效果较好,孔隙率较低,且力学性能较好,其拉伸强度比交织混编法制备的复合材料拉伸强度提高了46%,剥离强力提高了39%。