技术问答

化纤丝使用问与答问化纤丝回弹率如何检验? 答回弹率通常指弹性恢复率。检验化纤丝的回弹率有定负荷法与定伸长法两种。取一根样丝,加一定负荷,保持一定时间,然后去除负荷使样丝回复,测量其回缩后长度与初始长度之差的百分率,用此法测得的回弹率称定荷回弹率;将一根样丝拉伸到一定伸长(一般为丝的3～5%),保持一定时间后去除应力,使样丝回复一定时间后,再测量其回缩长度与初始长度之差的百分率,用此法测得的回弹率称定伸长回弹率。目前用定伸长回弹率来检验丝的回弹性能较多,一般在Y361型单纱强力机上进行测试。     

棉/双组分短纤混纺织物的弹性性能测试分析

为探明PTT／PET双组分短纤与棉混纺织物的弹性性能,对其拉伸性能、定伸长和定负荷反复拉伸弹性回复性能、折皱回复性能分别进行了测试分析。结果表明,在定伸长和定负荷反复拉伸条件下,棉／双组分短纤混纺织物的弹性回复性能优良,弹性回复率接近于棉氨包芯纱织物和棉／XLA包芯纱织物;其折皱回复性能良好,优于棉氨包芯纱织物,与棉／XLA包芯纱织物相近。     

针织物拉伸变形与回复性研究

易拉伸变形的特性影响了针织物的使用寿命,并且随着人们对于服装耐穿性要求的提高,研究针织物的拉伸变形和回复性能,对针织物的实际生产及质量控制有重要作用。使用单向拉伸测试仪对3种不同成分的纬平针织物进行了拉伸断裂、定伸长拉伸和定负荷拉伸试验,并对测试结果进行对比分析。针织物在小变形定伸长、定负荷反复拉伸作用,特别是沿经向拉伸时织物可以保持较高的弹性回复性。虽然纬向一般有较高的延伸率,但在大变形的定伸长、定负荷反复拉伸时,会造成线圈结构内部的变形。     

文胸肩带拉伸性能测试分析

以文胸肩带为研究对象,基于织物的主要力学性能和拉伸弹性指标,结合肩带自身造型和使用特点,进行拉伸断裂试验和定伸长反复拉伸试验,获得肩带的各拉伸性能指标。基于文胸肩带拉伸曲线的自身特征,结合曼列狄斯（Meredith）法确定纤维屈服点的作图过程,探讨肩带有效弹性终点的确定方法。应用配对检验的方法分析了肩带单次拉伸和5次反复拉伸后弹性回复率、塑性变形率变化的差异显著性,结果表明肩带在长时间使用过程中,其弹性回复率会随使用时间的累积发生显著衰变,其塑性变形率会产生显著积累。应用方差分析和协方差分析探讨了疲劳伸长对肩带弹性回复率、塑性变形率的影响,结果表明肩带的拉伸回弹性能与正常使用条件下的疲劳伸长无关。     

精干罗布麻纤维的拉伸性能

探讨了常态下和热处理后精干罗布麻单纤维的拉伸性能。着重探讨了处理温度、处理时间对纤维断裂强度、断裂伸长率以及断裂功的影响。随着处理温度的升高和处理时间的延长,纤维的断裂强度、断裂伸长率以及断裂功在整体上呈现下降趋势;与常态相比,120℃处理后纤维拉伸性能有明显下降;在180℃以上,纤维的以上指标下降程度增大;时间对纤维拉伸性能的影响小于温度,且在210℃时,纤维的各指标随时间变化明显。试验表明:精干罗布麻纤维的拉伸属高强高模低伸长类型,且纤维具有较好的拉伸性和较好的耐热性。     

聚丙烯腈纤维及其与矿物纤维配抄对密封材料性能的影响

探讨了聚丙烯腈纤维及其与矿物纤维配抄对密封材料性能的影响。结果表明,聚丙烯腈纤维长度、宽度分布范围广、粗度大,细小纤维比例高,是一种高支化纤维原料。随着聚丙烯腈纤维用量增加,拉伸强度和回弹率上升,压缩率下降,在聚丙烯腈纤维用量为30%时,拉伸强度15.25MPa,压缩率9.04%,回弹率34.67%,相较于未添加聚丙烯腈纤维,拉伸强度上升61.7%,压缩率下降34.8%,回弹率上升131.6%,密封性能提高显著。在聚丙烯腈纤维和矿物纤维配合使用时,随着聚丙烯腈纤维用量减少,矿物纤维用量增加,压缩率上升,回弹率和拉伸强度下降。3种矿物纤维中,FKF复合矿物纤维拉伸性能最优,Lapinus矿物纤维回弹性能最优。     

网孔型经编间隔织物压缩性能研究

选取厚度为15 mm的菱形网孔型涤纶经编间隔织物为研究对象,测试并分析其长期疲劳性、加载不同质量臀部模块时的压力分布特性以及落球回弹性。结果表明,经编间隔织物具有良好的抗疲劳性能,经2万次定载荷动态压缩后,织物厚度损失率基本趋于稳定;织物的柔软性增强了缓压能力,间隔纱能够起到支撑作用;在较小的动态冲击压力下,双层叠加经编间隔织物的平均回弹率为52.5%,织物的缓压性能较好。     

XLA弹力纤维拉伸回复性的试验

对XLA纤维的弹性回复率进行试验。结果表明,XLA弹性纤维在拉伸低于130％时能完全回复,大于200％时急、缓弹回复率急剧下降。拉伸时间在3min内对于XLA纤维弹性回复率影响不大。为此,XLA纤维在成纱和织造中,其拉伸倍数应低于200％。     

XLAS弹力纤维拉伸回复性的试验

对XLA纤维的弹性回复率进行试验.结果表明,XLA弹性纤维在拉伸低于130%时能完全回复,大于200%时急、缓弹回复率急剧下降.拉伸时间在3min内对于XLA纤维弹性回复率影响不大.为此,XLA纤维在成纱和织造中,其拉伸倍数应低于200%.     

国内外弹性纤维的现状与发展

通常,弹性纤维是指具有高断裂伸长、低模量和高回弹性的合成纤维.一般来说,可从3个方面来衡量纤维的弹性:一是较低的模量,即发生形变所需的外力较小,二是较大的伸长率;三是较高的弹性回复性能.     

FRP-水泥砂浆抗弯性能的研究

利用三点弯研究了水泥砂浆外贴碳纤维和芳纶纤维片材后的抗弯性能,并对2种纤维进行表面处理,探讨纤维的表面处理对FRP水泥砂浆体系抗弯性能的影响。结果表明,用等离子体分别对碳纤维和芳纶纤维进行表面处理,CFRP和AFRP水泥砂浆的最大断裂载荷都能显著提高,而且构件在受弯过程中没有发生剥离破坏,FRP被拉断,纤维高强的特点得到充分发挥。     

Long-Unidirectional Palm and Sisal Fibers Reinforced Composite: An Experimental Investigation

This paper focuses mainly on investigating the mechanical properties of mortar reinforced with long-unidirectional vegetable fibers such as palm fibers and sisal fibers. The mechanical properties of fibers are also studied by considering fiber tensile test and fiber coupling test to analyze the twist-extension coupling and the tensile strength. Fibers were manually extracted from palm and sisal leaves. Laminated mortar specimens with fibers volume fraction ranging between 0% and 1.95% were prepared. The long unidirectional oriented fibers were placed on the lower part of the mortar. The influence of curing conditions on flexural strength of laminated mortar specimens was analyzed by considering two curing conditions: WCCC (wet chamber curing condition) and LCC (laboratory curing condition). Results confirm that the optimum fiber volume fraction was evaluated as 1.4% for Palm fiber-reinforced mortar. Better mechanical performance was accorded to the Palm fiber reinforced mortar in WCCC case due to the availability of water which is necessary to cement hydratation. Long Sisal fiber submitted to a tensile load shows coupling phenomenon between twist and extension which has a mechanical effect on the matrix behavior.     

PTT/毛混纺织物的回弹性能

实测了PTT／毛混纺织物弹性产品在定伸长率为10％时及定负荷为10N时的弹性回复率及织物的应力松弛。分析了织物弹性回复率与伸长率之间的关系、经纬向紧度和组织等因素对弹性回复率的影响及织物应力松弛特征。     

用红外光谱和强伸性分析细化羊毛的二级结构转变

基于拉伸应力-应变曲线和显微红外光谱测量,分析具有不同细化率羊毛纤维的拉伸行为及构象转变.强伸实验表明,随着羊毛细化率(30%,50%,70%,90%,110%)增加,纤维的断裂应力增大,断裂伸长率降低.在本方法中屈服变形区的残留率110%拉伸率纤维还有68%.基于显微红外光谱图S—O吸收峰以及酰胺Ⅰ和酰胺Ⅲ带的分析,与力学性质相对比,表明拉伸不仅发生了纤维大分子从α螺旋构象转变为β折叠构象,还存在纤维的结构滑移.     

Influence of fiber surface modifications on the mechanical behavior of Vetiveria zizanioides reinforced polymer composites

The natural fiber is pretreated with chemicals namely, alkali, peroxide, and benzoyl chloride. Composites are prepared using chemically treated fibers as reinforcements and mechanical characteristics are tested. The results confirmed that, benzoylation improved the tensile, compressive, and impact strengths of the composite by 113%, 56.78%, and 95%, respectively. Peroxide treatment has improved the flexural strength by 56.13% and improved the elongation of the composite during tension, flexure, and compression tests. The surface morphology showed minimal defects in the benzoylated composite and hence, benzoylation is suggested for the best overall behavior and peroxidation for enhanced bending and elongation.     

Analysis of flexural strength of preoxidized fiber-reinforced composites made by a nonwoven process and hot-pressing

Preoxidized fiber was used here as a reinforcement for the first time. Polypropylene fiber was used as resin matrix, and the preform with the two types of fiber was prepared by a nonwoven process. Then, hot-pressing was applied to make a treatment for the preform, and the thermoplastic composites reinforced with preoxidized fiber were prepared. The effects of the hot-pressing temperature, hot-pressing pressure, weight percentage of preoxidized fiber, and nonwoven process on bending failure strength along the machine direction (MD) and transverse direction (CD) were studied under a three-point bending load. It was concluded that the flexural strength of the composites along MD and CD decreases with increasing hot-pressing temperature and hot-pressing pressure, while an initial increase and then decrease was observed with the increase in the weight percentage of preoxidized fiber. However in both directions, flexural strength of the composites is influenced significantly by the nonwoven process. Finally, the bending failure mode of the composites generated micro-flaws, which can be observed on the center surface of the composites. The micro-flaws extend to the ends along the thickness direction of the composites, and plastic bending failure is observed due to partial delamination.     

双组分纤维束拉伸曲线特征指标及应用研究

针对纤维束拉伸曲线的峰后区间特征 ,首次提出了描述其特征的 9个新指标 ,即后断裂伸长、后断裂伸长率、相对后断裂伸长率、后断裂功、断裂总功、后断裂功系数、后区 1 2负荷伸长率、后区 1 2伸长负荷率、后断裂效率。并对于双组分混合纤维束拉伸特征作了探索性试验研究     

锦葵茎皮纤维增强复合材料的力学及隔声性能

为拓宽锦葵茎皮纤维的应用领域,以锦葵茎皮为原料,采用碱脱胶工艺提取锦葵茎皮纤维,并以碱处理的锦葵茎皮纤维为增强体,聚丙烯纤维为基体,制备纤维质量分数分别是0%、10%、20%、30%、40%的纤维增强复合材料,探讨了纤维质量分数对锦葵茎皮纤维增强复合材料的拉伸、弯曲及隔声性的影响。研究结果表明：当纤维质量分数为30%时,锦葵茎皮纤维增强复合材料的拉伸断裂强度、拉伸模量、弯曲模量均最高,弯曲强度随着锦葵茎皮纤维质量分数的增加出现逐渐增大的趋势;当纤维质量分数超过10%时,复合材料的隔声性随着发声频率增加出现先增大后减小的趋势,同一发声频率,含量越低,隔声性能越差,当纤维质量分数超过30%后,电压峰值衰减率反而下降。     

Effect of chopped/continuous fiber,coupling agent and fiber ratio on the mechanical properties of injection-molded jute/polypropylene composites

This paper presents the development of jute/polypropylene (PP) composites by twin-screw extrusion and injection molding. Jute/PP was compounded using twin-screw extruder and injection molded. The effects of chopped/continuous fibers, coupling agent and fiber ratio on mechanical properties were investigated. Tensile and flexural moduli of continuous jute/PP were greater than those of chopped fiber/PP. Tensile, flexural and impact strengths were greater in chopped fiber/PP along with elongation at break. Coupling agent improved the tensile and flexural strengths, and these increased with fiber content, whereas impact strength and elongation at break decreased with fiber loading. The results were analyzed using ANOVA and regression analyses.     

玻璃纤维/光敏树脂复合材料的3D打印及其力学性能

为解决光固化3D打印树脂材料强度低的问题,将玻璃纤维与光敏树脂复合,采用光固化3D打印技术制备玻璃纤维增强复合材料,分析了玻璃纤维经硅烷偶联剂改性处理以及玻璃纤维的铺层方式对复合材料力学性能的影响.结果表明:玻璃纤维可提升复合材料的拉伸强度和弯曲强度,相比于未处理的玻璃纤维,经硅烷偶联剂处理的玻璃纤维对复合材料力学性能...