接枝法亲水改性腈纶的研究

采用两步法接枝共聚改性工艺实现腈纶织物亲水改性。通过探索溶胀剂、乳化剂、引发剂的种类和用量,以及活化预处理接枝共聚反应的工艺,确定接枝改性的最佳条件。结果表明:在溶胀剂氯苯7．0g／L, 乳化剂壬基酚聚氧乙烯醚(OP)2．1g／L,引发剂过氧化二苯甲酰(BPO)2．5g／L,亲水性酰胺类单体质量分数 2．0％,活化预处理温度75℃,活化时间30 min,接枝共聚反应温度85℃,反应时间60min,再经浓度为2．0g／ L碳酸钠溶液处理,腈纶织物的吸湿率达到7．0％。     

聚丙烯腈纤维吸湿改性方法及研究现状

综述了国内外吸湿性聚丙烯腈(PAN)纤维的研究现状;阐述了PAN纤维的吸湿机理及影响吸湿性的因素;详细介绍了改善PAN纤维的吸湿性的化学方法和物理方法;PAN纤维吸湿改性化学方法有通过聚合和共聚引进亲水基团、与亲水物质接枝共聚、对纤维表面进行碱减量处理、纤维表面的亲水整理、等离子体处理等;PAN纤维吸湿改性物理方法有与...     

纳米ATO的表面修饰及抗静电腈纶的制备

以聚丙烯酰胺(PAM)为分散剂,制备纳米ATO(SnO2·Sb2O3)导电粉末水相悬浮液,并用硅烷偶联剂修饰,将修饰后的纳米ATO悬浮液加入到聚丙烯腈原液(NaSCN溶剂)中共混,得到蓝绿色的聚丙烯腈共混原液。采用Zeta纳米粒度与电位分析仪、热台偏光显微镜、红外光谱等仪器测试了纳米ATO微粒在聚丙烯腈原液中的分散性能;用流变仪研究了共混原液的流变性能。在中型湿法纺丝机上纺制了2h左右的腈纶纤维,不堵喷丝孔。测试了纤维的力学性能和抗静电性能,用DSC和TG研究了纤维的热性能。     

Synthesis and electrospinning of well-defined polymer brushes by modification of polyacrylonitrile

As one of the most important precursors, polyacrylonitrile (PAN) and its functionality gained extensive attention but faced challenges in the preparation of nanofiber by electrospinning technology. Herein, poly(acrylonitrile-g-ethylene alcohol) (PAN-g-PEG) were succussfuly synthesized by the modification of PAN, using the methods of Click Chemistry and Mitsunobu reaction sequentially. Firstly, well-defined PAN was prepared by Cu(0)-mediated controlled/living radical polymerization with a molar ratio of [AN]₀:[EBiB]₀:[Cu]₀:[TEMED]₀?=?500:1:1:2. Tetrazole-containing PAN was then successfully modified by nitrile-Click Chemistry, which sodium azide and ammonium chloride was used as substrate and catalyst, respectively. Using Mitsunobu reaction, PAN-g-PEG was obtained from tetrazole-containing PAN and poly(ethyl alcohol) with the catalyst of diethyl azodicarboxylate and triphenylphosphine. After typical characterization, PAN-g-PEG nanofiber with the average diameter around 90 nm, was successfully prepared by electrospinning. The obtained PAN-g-PEG nanofiber has a smoother surface than PAN nanofiber, which suggests that a new modification approach of PAN nanofiber is successfully achieved.     

Difluorocarbene modification of polymer and fiber surfaces

Difluorocarbene (difluoromethylene, :CF₂) generated by the pyrolysis of sodium chlorodifluoroacetate has been shown to irreversibly modify the surfaces of polymers and fibers. The critical surface tension values of several polymers are shown to decrease with increasing exposure to difluorocarbene vapors and ultimately approach the critical surface tension values of partially fluorinated polyethylenes. The rate-controlling step appears to be the diffusion of difluorocarbene from the precursor to the polymer substrate. The nature of the interaction between difluorocarbene and the polymer surface is unknown; however, the absence of infrared bands due to C? F bonds in attenuated total reflection measurements tends to establish the mono-molecular-like character of the modified surface.     

Improvement of carbon nanotube dispersion in electrospun polyacrylonitrile fiber through plasma surface modification

In this study, surfaces of multiwalled carbon nanotubes (CNTs) were functionalized with poly(hexafluorobutyl acrylate) (PHFBA) thin film using a rotating-bed plasma-enhanced chemical vapor deposition (PECVD) method without imparting any defects on their surfaces. Polyacrylonitrile (PAN) electrospun polymer fiber mats and composite fiber mats with CNTs and functionalized CNTs (f-CNTs) were prepared. The wettability and chemical and morphological properties of the synthesized fiber mats were investigated, and the dispersion of CNTs and f-CNTs in the polymer matrix was compared according to the contact angle results of electrospun polymer mats. According to the chemical and morphological characterization results, PHFBA-coated CNTs were dispersed more uniformly in the polymer matrix than the uncoated CNTs. The f-CNTs/PAN composite fiber mat exhibits a lower surface energy than the pristine CNTs/PAN fiber mat. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47768.     

Physical modification of polyacrylonitrile precursor fiber: Its effect on mechanical properties

Polyacrylonitrile precursor fiber of a special grade for making carbon fibers was modified by stretching in the prestabilization stage to various extents. The effect of such stretching on tensile properties of the original precursor fiber, intermediate (oxidized) fiber, and resultant carbon fiber prepared through a continuous process was monitored. Improvements in tensile modulus of fibers at various stages were observed with increasing stretch ratios. However, no obvious enhancement of tensile strength of final carbon fibers was found. © 1994 John Wiley & Sons, Inc.     

含多官能团功能聚丙烯腈纤维抗菌消臭机理的研究

通过 FT- IR、1 3 CNMR、XPS、和 SEM等手段 ,对含多官能团聚丙烯腈抗菌消臭纤维在抗菌前后的物理化学结构和微观形貌的变化进行分析研究 ,探讨了其抗菌作用的机理和模式。聚丙烯腈型抗菌消臭纤维对不同有害病菌的抗菌作用是多种抗菌基团和协同基团 ,通过抑制细菌繁殖生长和杀灭活性细菌的协同作用来实现的。改变细菌的生存环境和破坏其组织结构是其主要抗菌手段     

碳酸钙对聚合物纤维及薄膜的填充改性

介绍了碳酸钙(CaCO3)的填充改性的特点及其改性方法;详述了CaCO3在聚合物纤维、无纺布和薄膜中的应用;探讨了纤维、无纺布及薄膜用CaCO3的要求,CaCO3填充母粒的制备方法及其填充工艺流程。指出应选择CaCO3的粒度及其分布,选用合适的偶联剂和分散剂,才能制备出与基体树脂相容性好的填充母料。     

Structural modification and molding of polyacrylonitrile

Polyacrylonitrile can be compression-molded with conventional equipment if the inherent polymer particle structure is modified. With normal polymerization methods, a circumferential orientation in the polymer particle is obtained. This structure can be changed under the effects of shear to yield highly ordered, laminar particles with planar orientations. In this form, PAN can be compression-molded into tough, clear, chemically resistant articles with retention of the laminar structure. The polymer has been characterized by its x-ray diffraction and infrared spectrum which, in combination, distinguish it from previously observed forms of PAN.     

添加剂苯亚磺酸钠和HEDTA对腈纶纤维表面化学镀铜的影响

以次磷酸钠为还原剂在腈纶纤维表面进行化学镀铜,研究了单一添加剂苯亚磺酸钠和N-羟乙基乙二胺三乙酸(HEDTA)的用量对镀层电阻、增重率和阴阳极极化过程的影响。单一添加剂苯亚磺酸钠和HEDTA在一定浓度范围内能明显促进次磷酸钠的阳极氧化,从而提高增重率,降低镀层电阻,最佳质量浓度分别为苯亚磺酸钠40 mg/L、HEDTA 60 mg/L。对比研究了无添加剂镀液和分别添加了苯亚磺酸钠40 mg/L、HEDTA 60 mg/L以及复合添加剂(40 mg/L苯亚磺酸钠+60 mg/L HEDTA)的镀液的阳极和阴级极化曲线,通过扫描电镜观察了所得铜镀层的表面形貌。较之单一添加剂,40 mg/L苯亚磺酸钠+60 mg/L HEDTA复合添加剂主要抑制了次磷酸钠的阳极氧化,使得镀层表面更加均匀、细致和平整。     

Analysis of the heat-release mechanism during thermal stabilization of polyacrylonitrile fiber rope

Results of experimental studies of heat release during heating of polyacrylonitrile (PAN) rope are presented. The heating conditions for PAN rope samples of elemental fiber linear density 0.08, 0.10, and 0.12 tex to 330°C at rates 2, 3.5, and 5 K/min were selected to model thermal stabilization processes in an oxidation furnace. These data were used to determine the kinetic constants in the Arrhenius equation using the method proposed by L. I. Volkova. Experimental heat release in rope as a function of time at various heating rates was used to determine the kinetic reaction constants. Kinetic constants of the generalized reaction were determined for all tested ropes and conditions. A heat-release equation was formulated based on the kinetic constants for each PAN rope sample. The rope mass change as a function of time M(t) expressed in fractions and represented as a second-order polynomial was determined from the rope mass loss at heating rate 3.5 K/min.     

阻燃腈纶的制备

采用铜离子处理腈纶,再与水合肼及反应助剂组成的混合水溶液反应,制备了阻燃腈纶,探讨了处理工艺条件对纤维性能的影响。结果表明:在水合肼加入量20 mL,w(NaOH)为5%的NaOH 4.7 mL,质量分数为10%精炼剂9.4 mL,甩干时间3 min,热处理温度160℃,热处理时间180 min条件下,得到的阻燃腈纶断裂强度为2.15 cN/dtex,断裂伸长率为21.4%,极限氧指数为32.83%。     

Kinetics of diffusion in polyacrylonitrile fiber formation

A H₂O/dimethyl sulfoxide (DMSO) mixture was used as the coagulation bath of the wet‐spun process for polyacrylonitrile fibers. Diffusion behaviors of coagulate and solvent of the protofibers were studied. Diffusion coefficients of H₂O and DMSO of the protofibers, prepared by acrylonitrile (AN) homopolymers, were also determined. It was found that diffusion coefficients of H₂O and DMSO in the protofibers prepared by AN homopolymers, synthesized by DMSO solution polymerization, are highest compared with those of AN homopolymers synthesized by H₂O/DMSO mixture suspension polymerization and aqueous suspension polymerization. With increasing polyacrylonitrile concentration in the dope, diffusion coefficients of H₂O and DMSO decreased continuously. Diffusion coefficients of H₂O and DMSO increased concomitantly with increasing bath temperature, but the changes of diffusion coefficient values were less prominent when the temperature increased beyond 60°C. When DMSO concentration in the coagulation bath was 55 wt %, the values of diffusion coefficients of H₂O and DMSO were minimal. Diffusion coefficients increased with increasing jet stretch minus ratio. When the protofiber radius was increased, there was a corresponding increase of diffusion coefficients of H₂O and DMSO. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1529–1533, 2005     

吸湿发热聚丙烯腈纤维的性能研究

采用傅立叶变换红外光谱、扫描电子显微镜、X射线衍射仪和热重分析仪对交联改性制备的吸湿发热聚丙烯腈(PAN)纤维的吸放湿性能进行表征,与普通PAN纤维及进口吸湿发热PAN纤维进行对比。结果表明:交联改性制备的吸湿发热PAN纤维红外光谱出现了较强的羟基峰和羧酸盐的伸缩振动峰,相比普通PAN纤维,表面沟槽加深、粗糙度增加,在100℃内失重率达17.17%,热分解温度提高近70℃,结晶度大幅下降,力学性能降低;交联改性PAN纤维的吸放湿性能较普通PAN纤维大幅度提高,并高于进口吸湿发热PAN纤维,其平衡回潮率约30%,吸湿积分热达155 J/g。     

w(残余单体)对聚丙烯腈聚合物及原丝性能影响

在相同聚合条件下完成聚合,聚合完成后进行脱单,根据实验需要调整脱单工艺,设计了w(残余单体)=10%、7%、4%、2%、1%、0.5%6种条件实验,在纺丝机头收取不同条件下聚丙烯腈合液样品,对聚合液样品的转化率、落球黏度、增比黏度进行测试;在相同纺丝条件下收取不同条件的聚丙烯腈聚原丝样品,对样品进行力学性能分析和截面形状分析。结果表明,随着w(残余单体)的下降,机头纺丝液转化率、落球黏度下降,增比黏度上升;随着w(残余单体)的降低,原丝单丝强度、拉伸模量上升,断裂伸长下降;在相同纺丝条件下,尤其是相同凝固条件下,随着w(残余单体)的下降,原丝截面从圆形向腰形转变。     

聚丙烯腈材料改性方法及研究进展

综述了近年来聚丙烯腈材料改性方法的研究进展,主要包括共聚改性、接枝改性、共混改性、后整理法以及增塑改性.分析了不同改性方法的特点,并对聚丙烯腈材料改性方向和未来发展趋势做出了展望.     

Analytical characterization of weather-degraded polyacrylonitrile fiber

Polyacrylonitrile (PAN) fiber was analytically characterized to identify the structural changes that occur due to atmospheric degradation. Degradation structures comprised of C?C, C?N, and C?O species were identified using infrared spectroscopy. A significant decrease in the molecular weight was measured using size exclusion chromatography. PAN–acrylate copolymer fibers were analyzed and found to exhibit the same type of structures and changes in properties upon atmospheric degradation.     

亲水性多孔聚丙烯腈纤维的研究

将聚丙烯腈(PAN)与聚氧化乙烯(PEO)共混后湿法纺丝,经水洗后处理,制成具有不同微孔结构的改性PAN纤维,然后在NaOH溶液中水解,得到亲水性多孔PAN纤维(HM-PAN)。借助红外光谱和扫描电镜表征了HM-PAN的化学结构和形貌;讨论了HM-PAN的亲水性能和力学性能。结果表明:相同水解条件下,随PEO含量增大,HM-PAN中引入的亲水基团增多,表面形成的孔穴加深、数量增多,纤维的亲水性能提高;在相同PEO含量下,通过控制水解时间、HM-PAN的孔隙结构及亲水基团数量,可以提高HM-PAN对水分的吸收及转移性能。PEO质量分数为10%的HM-PAN试样的平衡吸水倍率可高达10.48 g/g,最大芯吸高度为13.5 cm,保水率高达98.1%。HM-PAN中微孔产生的应力集中以及大分子排列规整性的破坏,导致纤维的力学性能有所下降,而水解时张力的施加可有效降低其下降幅度。     

Surface modification of polyacrylonitrile based ultrafiltration membrane

Ultrafiltration membrane based on polyacrylonitrile prepared by phase inversion method using zinc chloride as an additive showed more than 90% rejection for BSA and 90–110 lm^?2 h^?1 water flux. The surface modification of this membrane was studied using ethanolamine, triethylamine, sodium hydroxide, and potassium hydroxide solutions. The effect of base treatment time and temperature on water flux and rejection was investigated. The membranes exhibited swelling by NaOH treatment followed by deswelling by HCl post‐treatment, similar to pH responsive membranes. The treatment by organic as well as inorganic bases improved water flux with a slight lowering in BSA rejection by dead‐end mode type treatment. A 230% increase in water flux was achieved by sodium hydroxide treatment in crossflow mode without a noticeable pore swelling by SEM. The contact angle of the modified membranes was decreased as compared to the unmodified one indicating appreciable surface modification. As the treatment time or temperature increased, the ESCA analysis showed increased population of Na‐carboxylate groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4378–4385, 2006