低温等离子体对ＰＢＯ纤维表面改性的研究

 为提高ＰＢＯ纤维／环氧树脂复合材料的剪切强度,采用低温等离子体结合涂层技术对聚对苯撑苯并双唑（ＰＢＯ）纤维进行表面改性,分别用ＳＥＭ、ＩＲ对等离子体处理前后纤维表面形态、化学结构进行了表征,通过复合材料层间剪切强度测试,研究不同处理方式对复合材料层间剪切强度的影响。结果表明,等离子体处理后纤维表面粗糙度增加,极性增强。经低温等离子体结合涂层技术处理后,ＰＢＯ纤维／环氧树脂复合材料的层间剪切强度得到显著提高,较未处理样品提高了３９％。     

水解/接枝处理对F-12纤维/环氧复合材料力学性能的影响

采用氢氧化钾稀溶液对F-12纤维进行表面处理,将—COOK离子对引入到F-12纤维表面,进而引发不同接枝单体的接枝,并分析了不同接枝单体和接枝时间等对F-12纤维拉伸强度及其环氧复合材料层间剪切强度的影响。研究表明,在温和条件下将—COOK离子对引入到F-12纤维表面,引发环氧氯丙烷接枝,可以提高F-12纤维/环氧复合材料的层间剪切强度。     

纳米SiO2对环氧复合材料壳体纤维强度转化率的影响

以纳米SiO2作为增强材料改性环氧树脂基体，通过NOL环复合材料剪切强度测试，研究不同含量纳米SiO2粒子对复合材料层间剪切强度的影响。结果表明：纳米SiO2含量在6％时，改性效果最好，复合材料层间剪切强度提高约60％；F-12纤维强度转化率提高约9．4％。     

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。     

纤维缠绕压力容器表面损伤试验研究

通过制作纤维缠绕标准容器试样,并对部分试样表面纤维制作人工损伤,与标准容器试样比较爆破压力,并进行有限元分析、研究其破坏机理,对强度影响程度进行评估。结果表明：表面纤维损伤会造成压力容器在应力水平较低情况下局部发生层间剪切破坏,损伤容器爆破强度平均值降低22．4％,损伤修复后的容器爆破强度降低12．2％。     

环氧树脂/PBO纤维复合材料性能研究

对环氧树脂(EP)/聚对苯撑苯并二恶唑(PBO)纤维复合材料的性能进行初步研究。结果表明,用浓度70%的甲基磺酸(MSA)溶液对PBO纤维表面进行处理,可改善PBO纤维与EP基体的粘结强度,但同时使PBO纤维的拉伸性能降低;对PBO纤维处理2h后,以胺类固化剂固化的EP/PBO纤维复合材料的层间剪切强度比处理前提高41%,以酸酐固化剂固化的EP/PBO纤维复合材料的层间剪切强度比处理前提高48%;前者的层间剪切强度大于后者。     

纤维表面处理对F-12复合材料剪切性能的影响

本文采用活性涂层、刚性涂层、柔性涂层分别对 F－ 12纤维进行表面处理,并研究了不同涂层对 F－ 12/AE4环氧 NOL环复合材料剪切强度的影响。试验结果表明,各种涂层对其复合材料的剪切性能都有一定的影响。其中,刚性涂层有利于提高 NOL环的剪切强度。     

纤维表面处理对 F－ 12复合材料剪切性能的影响

本文采用活性涂层、刚性涂层、柔性涂层分别对 F－ 12纤维进行表面处理,并研究了不同涂层对 F－ 12/AE4环氧 NOL环复合材料剪切强度的影响。试验结果表明,各种涂层对其复合材料的剪切性能都有一定的影响。其中,刚性涂层有利于提高 NOL环的剪切强度。     

高性能纤维表面改性研究进展

高性能纤维具有优异的性能,广泛用于宇航和军事领域,但是其与树脂基体之间的界面粘接性能较差,复合材料的层间剪切强度较低。针对这一复合材料体系,全面论述了提高其性能的几种方法以及各种方法的优缺点,其中包括纤维表面接枝、偶联、聚合物涂层、冷等离子体、γ射线辐射和超声波处理等,同时介绍了改性纤维的性能表征方法。     

纳米SiO2改性EP对基体力学性能和芳纶纤维/EP复合材料界面性能的影响

研究了纳米SiO2对环氧树脂(EP)基体力学性能的影响,并进一步采用对位芳纶纤维(F-12)增强环氧树脂,制备了NOL环复合材料,通过复合材料层间剪切性能测试考核了F-12与环氧树脂之间的界面粘接性能.结果表明:环氧树脂中添加适量的纳米SiO2能够有效提高环氧树脂浇注体的拉伸强度、拉伸弹性模量、冲击强度.纳米SiO2的加入,可以有效改善F-12与环氧树脂基体之间的界面粘接性能,降低复合材料的空隙率,F-12/纳米SiO2(6%)-EP复合材料的层间剪切强度(ILSS)提高约60.3%.     

Identification of fiber misalignment in continuous fiber composites

Misaligned fibers are invariably present in nominally unidirectional high‐performance composites. Such misaligned fibers are known to affect key mechanical properties of the composite, such as the longitudinal compressive strength, longitudinal tensile modulus, fatigue endurance, shear strength, and delamination resistance (1). In this paper we present a method for the automated detection of large angle fiber misalignment (θ > 40°) in continuous fiber‐reinforced composite materials. The method relies on the application of a series of geometrical criteria based upon measurements routinely obtained during optical scanning of polished sample cross‐sections. As such, the technique is ideal for the automated identification of highly misaligned fibers in large‐area (∼ cm²) specimens that may contain several millions of individual fiber images. The criteria applied take into account the fact that prepared cross‐sections of such materials contain many damaged fibers as a result of attrition during polishing. Data obtained from three pultruded unidirectional rods reinforced with continuous carbon filaments are used to illustrate the effectiveness of this method in identifying regions where large angle misalignment occurs.     

Direct fiber formation and fiber properties of aromatic polyoxadiazoles

A novel and simple fiber formation process has been developed to fabricate aromatic polyoxadiazoles. The aromatic copolyoxadiazole solution prepared from terephthalic acid, isophthalic acid, and hydrazine sulfate in fuming sulfuric acid was utilized directly as spinning solution and was successfully wet-spun to form fiber into a coagulating bath containing sulfuric acid. In the wet-spinning process, selection of the coagulating bath was the most important factor, and the best results were obtained by the use of approximately 50 wt-% aqueous sulfuric acid. It was easy to prepare a polyoxadiazole fiber having a tenacity of more than 4 g/den. and an elongation of more than 10%. In addition, the fiber properties reached to a tenacity of 6 g/den. and an elongation of 12% under optimum spinning conditions. The wet-spun polyoxadiazole fiber showed an almost round cross section and a clear skin-core structure by microscopic observation. The fiber had a high level of thermal and dimensional stability and a high proportion of property retention at elevated temperatures, as well as all-round general fiber properties.     

锦纶纤维特性及纤维骨架材料的发展

一、锦纶骨架材料世界应用概况 锦纶66的合成及纺丝技术于1935～1937年由美国杜邦公司的Carothers发明，并于1938年实现了中试规模，第二次世界大战期间美国开始使用锦纶66帘布制造军用飞机轮胎，1947年后用于载重胎，到50年代后期，美国的载重胎用骨架材料几乎完全由锦纶66取代了人造丝。德国于1941年实现锦纶66工业化生产。日本1958年发明用锦纶6做轮胎骨架材料制造轮胎。     

Effect of polypropylene fiber processing conditions on fiber mechanical behavior

An investigation into the mechanical behavior of melt‐spun isotactic polypropylene (iPP) fibers is reported. Two different iPP formulations, PH835 and Exxon3854, synthesized using Ziegler–Natta and metallocene catalysts, respectively, and spun at take‐up velocities ranging from 1000 to 3000 m min^?1 were subjected to uniaxial tensile loading, cyclic loading and creep tests. The strain rate sensitivity was determined by performing strain rate jumps. Injection molded specimens from the same iPP formulations were tested under the same conditions. The fiber birefringence increases slightly with increasing take‐up velocity, while the crystallinity is approximately insensitive to this process parameter in this range of velocities. Fibers from the two iPP samples behave differently at large plastic strains despite having the same birefringence and crystallinity. Differences are also seen in creep. The behavior of fibers is significantly different from that of the injection molded samples of the same iPP and same crystallinity. These have lower strain hardening rate, smaller failure strains, close to zero strain rate sensitivity and exhibit a yield point phenomenon. The difference is associated with the different nature and spatial organization of the crystals and inter‐crystalline amorphous and mesomorphic phases. © 2014 Society of Chemical Industry     

Interpretation of fiber fragmentation in carbon/epoxy single fiber composites: Possible fiber pre-tension effects

The fiber straightening pre-tension applied during the sample preparation of single fiber composites is suggested here to significantly affect the number of fragments as well as the value of the Kelly-Tyson interface shear strength obtained from single filament composite tests. This implies that fragmentation tests performed under seemingly identical conditions, but in which the fiber pre-tension is not accurately controlled during sample preparation, might yield widely differing experimental results. We present and discuss a new set of experimental results dealing with fiber pre-tension effects in carbon/epoxy single fiber composites.     

工程用聚丙烯腈纤维为基体的羧酸纤维的制备

采用断裂强度为12.26 cN/dtex、玻璃化转变温度高于250℃的工程用聚丙烯腈纤维(PAN-EF)为基体纤维,通过二甲基亚砜(DMSO)和氢氧化钠(NaOH)混合水解制备羧基含量(M_COOH)高且力学性能好的PAN-EF基羧酸纤维(PAN-EF-COOH),探讨了DMSO浓度、反应温度和反应时间对纤维水解效果的影响。结果表明:加入溶胀剂DMSO,可以降低PAN-EF在碱性条件下的水解难度;随着DMSO浓度增加、反应温度提高、反应时间延长,PAN-EF-COOH的M_COOH显著增大,但断裂强度逐渐降低;PAN-EF在NaOH质量分数0.1%、DMSO体积分数50%、反应温度120℃、反应时间2.5 h条件下水解,可以获得M_COOH较高且力学性能好的羧酸型纤维PAN-EF-COOH,纤维M_COOH为2.00 mmol/g、断裂强度为9.92 cN/dtex。     

The viscosity of fiber suspensions at low fiber volume fractions

The viscosities of suspensions of glass fibers in an aqueous solution of sucrose have been studied by use of a capillary viscometer. In the aligned condition in the capillary, the viscosity depends little on shear rate within the range studied or on fiber length, but increases with increasing volume fraction of the fibers. The entrance effect was found to depend strongly on fiber volume fraction and fiber length: this indicates that the suspensions are relatively resistant to flow during the initial stages while alignment takes place.     

P84纤维和普抗纤维性能介绍及应用

1前言 随着国家对大气治理力度的加大,对排放浓度要求越来越严,其它一些除尘器已不能满足新标准的要求,唯有袋式除尘器能实现这一点.滤袋作为袋式除尘器的关键部件,其性能直接影响着排放浓度和使用寿命,滤袋器的发展,远远跟不上滤袋本身的发展,新的滤材不断出现,下面仅对两种性能较突出的P4纤维和普抗纤维的性能及应用进行初步探讨.     

Pineapple leaf fiber reinforced thermoplastic composites: Effects of fiber length and fiber content on their characteristics

Pineapple leaf fiber (PALF) was used as a reinforcement in polyolefins. Polypropylene (PP) and low‐density polyethylene (LDPE) composites with different fiber lengths (long and short fibers) and fiber contents (0–25%) were prepared and characterized. The results showed that the tensile strength of the composites increased when the PALF contents were increased. It was observed that the composites containing long fiber PALF were stronger than the short fiber composites as determined by greater tensile strength. An SEM study on the tensile fractured surface confirmed the homogeneous dispersion of the long fibers in the polymer matrixes better than dispersion of the short fibers. The unidirectional arrangement of the long fibers provided good interfacial bonding between the PALF and polymer which was a crucial factor in achieving high strength composites. Reduction in crystallinity of the composites, as evident from XRD and DSC studies suggested that the reinforcing effect of PALF played an important role in enhancing their mechanical strength. From the rule of mixtures, the stress efficiency factors of the composite strength could be calculated. The stress efficiency factors of LDPE were greater than those of PP. This would possibly explain why the high modulus fiber (PALF) had better load transfers to the ductile matrix of LDPE than the brittle matrix of PP. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

生物酶在腈纶及涤纶改性中的应用

介绍了腈水合酶及酯酶分别在腈纶和涤纶改性中的应用。在腈水合酶的作用下 ,腈纶表面的氰基可水解生成亲水性较强的酰胺基 ,从而提高腈纶的抗静电性及吸湿性能 ,同时赋予腈纶酸性染料可染性能。酯酶可以催化涤纶大分子中的酯基水解 ,为疏水性的涤纶引入亲水性基团 ,明显提高涤纶的润湿性及手感。