建筑增强用聚丙烯腈纤维的耐海水腐蚀性研究

模拟混凝土应用的海洋环境,在常温(25℃)、氯化物浓度为5610 mg/L的海水中对建筑增强用聚丙烯腈(PAN)纤维进行浸泡处理,研究建筑增强用PAN纤维的耐海水腐蚀性,并与聚对苯二甲酸乙二醇酯(PET)增强纤维和聚丙烯(PP)增强纤维进行对比。结果表明:海水浸泡50 d后,建筑增强用PAN纤维的主要吸收特征峰无明显变化,且无新的吸收特征峰出现,纤维超分子结构变化较小,晶区取向度基本保持不变,结晶度略有增加;海水浸泡50 d后,建筑增强用PAN纤维的拉伸强度为1261 MPa、降幅0.63%,初始模量为18.6 GPa、增幅8.14%,其拉伸强度与PET增强纤维相当、约为PP增强纤维的1.8倍,初始模量约是PET增强纤维的1.4倍、PP增强纤维的3.2倍;建筑增强用PAN纤维、PET增强纤维、PP增强纤维的拉伸强度耐蚀系数分别为99.4%,99.2%,100.0%,建筑增强用PAN纤维的耐海水腐蚀性介于PP增强纤维和PET增强纤维之间,但其在海水中环境中具有优异的模量保持优势,可以更好地提高混凝土在海水环境中的耐受力。     

建筑增强用聚丙烯腈纤维的抗冻融性研究

在模拟混凝土配置时的冻融交替环境下,将建筑增强用聚丙烯腈(PAN)纤维置于(-20±2)℃的冷冻箱中冷冻12 h,随后取出在(25±2)℃的室温环境中融化12 h,对纤维进行90次冻融循环,研究冻融循环处理前后纤维结构和性能的变化,以强度损失率表征其抗冻融性,并与聚对苯二甲酸乙二醇酯(PET)增强纤维和聚丙烯(PP)增...     

建筑增强专用聚丙烯腈纤维的耐环境性研究

模拟土工建筑材料沥青及混凝土实际应用中的酸碱性和日晒环境,研究建筑增强专用聚丙烯腈(PAN)纤维的耐环境性,并与普通PAN高强纤维进行对比。结果表明:相较于普通PAN高强纤维,建筑增强专用PAN纤维在1 732 cm^-1处C=O伸缩振动峰较弱,并且结晶度和晶区取向度较高;经35 d日晒雨淋后,建筑增强专用PAN纤维的断裂强度和初始模量的保留率最高分别达到98.07%和96.43%;在50℃的极端酸性环境(pH值为1)中,建筑增强专用PAN纤维的断裂强度和初始模量的保留率均大于98%;建筑增强专用PAN纤维的热分解温度高于普通PAN高强纤维100℃以上;建筑增强专用PAN纤维的耐候性、耐酸碱性和耐热性均比普通PAN高强纤维好,能够更好地满足建筑材料的使用要求。     

聚丙烯腈纤维增强聚丙烯

聚丙烯腈（PAN）纤维是一种有趣的纤维，由于它们具有良好的力学性能，比如高抗冲性等，可用于生产增强热塑性塑料。这正是德国图林根纺织塑料研究所开发PAN纤维增强聚丙烯（PP）材料的原因之一。他们使用来自Dolan GmbH的PAN纤维进行开发，这种增强材料可使用同向双螺杆挤出机进行生产。已经进行的测试显示，这种增强材料具有高耐热变形能力，     

Cu盐对聚丙烯腈预氧化纤维增强作用研究

<正> 一 引言 在碳纤维的生产过程中,PAN纤维经过热稳定化处理成为预氧化纤维(PANOF),再经过高温碳化,制成碳纤维。随着热稳定化温度的升高和时间的增长,大分子链上的氰基发生环化聚合,生成稳定的梯型结构:     

聚丙烯腈增强纤维对腻子性能的影响

制备了不同配方的聚丙烯腈纤维增强腻子,参照相应的标准对腻子的抗裂、抗冲击和抗渗性能进行了表征。试验结果表明,纤维的应用有效地改善了腻子的上述性能。纤维在腻子中的临界长度为2mm。此外,纤维增强腻子展现出了更好的施工性能。KNP192聚丙烯腈纤维的最佳添加量为腻子粉质量的0.3%～0.4%。     

高性能纤维的耐碱性能研究

研究了芳纶、玄武岩纤维以及玻璃纤维的耐碱性能,分析了3种纤维分别在65℃、80℃、95℃的氢氧化钠溶液中,经不同时间的腐蚀后,3种纤维的力学性能以及其质量的变化情况.结果表明:芳纶的耐碱性能最优,断裂强力和断裂伸长保持率最大,玄武岩纤维其次,玻璃纤维最差,因此芳纶比玄武岩纤维和玻璃纤维更适合用于碱性环境中.     

聚丙烯腈纤维的改性

以阻燃、抗起毛起球、亲水、抗静电为主对聚丙烯腈纤维改性方法作了综述。介绍了国内聚丙烯腈纤维改性的状况 ,提出了应积极开发高附加价值的改性聚丙烯腈纤维的建议。     

聚丙烯腈中空纤维膜的研究

本文对聚丙烯腈中空纤维膜的原料组成，中空纤维的纺丝工艺与膜性能的关系，以及纺制不同结构中空纤维膜的纺丝工艺和方法进行了综述，提出了纺制耐热性好的聚丙烯腈中空纤维３膜可能的方法和意义。     

不同工艺制备的聚丙烯腈纤维的耐碱特性研究

模拟水泥混凝土的施工条件,试验测定了3种不同工艺制备的聚丙烯腈(PAN)纤维在碱性条件下的结构和性能变化。红外光谱(FT-IR)测试结果表明,在碱性介质的作用下PAN纤维发生一定程度的水解,广角X-射线散射(WAXS)分析表明,在碱性条件下PAN纤维的结晶度、晶粒尺寸、晶区取向因子均出现一定程度的下降。其中以碳纤维原丝生产工艺(PAN-1)制备的聚丙烯腈纤维分子质量最高,共聚单体含量最低,结晶度、取向度最高,耐碱腐蚀能力最好,强力保持率明显高于常规干法纺丝(PAN-2)和常规湿法纺丝(PAN-3)制备的PAN纤维,有潜力作为水泥混凝土防裂增强材料使用。     

Thermal stabilization of polyacrylonitrile fibers

Polyacrylonitrile (PAN) fibers pretreated with potassium permanganate have reduced the activation energy of cyclization and the oxidation time, and also improved the properties of the resultant carbon fibers. The activation energy of cyclization is reduced to 24 ± 1 kcal/mol from 30 ± 3 kcal/mol and the tensile strength of the carbon fibers increases by about 20?40%. The method of measuring the “aromatization index” (AI) value is modified and is recommended in checking the oxidation process. All fully stabilized PAN fibers have almost the same AI value. However, the oxidation time is decreases by 30 min when oxidation temperature is raised by 10°C.     

聚丙烯腈原丝的预氧化

主要阐述了预氧化反应的机理、改善预氧化的方法和与预氧化研究相关的表征技术,制备高性能碳纤维所需预氧丝的预氧化程度,以及预氧化工艺和预氧丝的表征参数与最终碳纤维性能的关系。     

Degradation of polyacrylonitrile in solution by alkali

This paper presents new data about changes which occur in viscosity, number-average molecular weight and the Huggins constant when polyacrylonitrile is degraded by alkali. The significance of these changes in relation to chain scission reactions, structural alteration and hydrolysis processes inherent in the overall degradation is considered in some detail. Tentative explanations for the apparent recovery in viscosity and molecular weight characteristics on extended exposure to dilute alkali are put forward.     

Low-surface-free-energy polybenzoxazine/polyacrylonitrile fibers for biononfouling membrane

We blended poly(3-phenyl-3,4-dihydro-2H-1,3-benzoxazine) (PBA) into polyacrylonitrile (PAN) to generate low-surface-free-energy fibers without fluorine and silicon elements for electrospinning. Liquid-state BA at room temperature can be solidified in electrospinning process using PAN as a medium through their miscible behavior. Results indicate that the mixing below 50 wt% BA into PAN matrix for electrospinning has no significant dropping beads, indicated a miscible PAN/BA system. Above 70 wt% BA in PAN solution could not be solidified completely after electrospinning, revealed apparent beaded fibers. The PAN/PBA blend fibers, obtained after curing at 300 °C, generated a superhydrophobicity because of the low-surface-free-energy PBA. In addition, laser scanning confocal microscope (LSCM) measurements were included to determine the relative amount of antibody that adsorbed to these PAN/PBA fibers to examine the biofouling-resistant property. The results showed an obviously decreased protein adsorption with increasing PBA fraction. The correlations between PAN and PBA would provide insight into the designing and developing of low-surface-free-energy fibers without fluorine and silicon elements to improve biofouling-resistant property.     

Derivative stress-strain curves of polyacrylonitrile fibers

Derivative stress-strain curves at constant strain rate for polyacrylonitrile copolymer fibers have been obtained by simple modification of conventional tensile testing apparatus. These derivative curves, considerably more complex and eventful than stress-strain curves, have been interpreted as direct records of changes undergone by the apparent Young's modulus during experiments which extend from infinitesimal strain to failure. Analysis of the data shows that these changes in the apparent Young's modulus cannot be accounted for to any significant extent by viscoelastic time effects and must therefore be consequences of the deformation process itself. In the light of this analysis, it is concluded that polyacrylonitrile fibers “soften” considerably in the strain range 0.5–3% and that they exhibit moderate “hardening” in the strain range which extends from ca 3% to the breaking strain (10%).