突破原丝瓶颈效应加速我国PAN炭纤维技术的发展

聚丙烯腈基炭纤维是高新技术领域中的重要原材料,制约基技术发展的瓶颈是原丝的研究。分析了长期以来国风原丝研究存在的综合基础弱,力量薄,研究单一,缺乏创新等问题,结合北京化工大学开展的T300及更高性能炭纤维原丝技术研究工作,探讨并提出了提高原丝基础和工艺研究的建议,认为点面结合、创新思维和不懈努力、集中攻关与广泛协作等是提高原丝研究水平的基础与保证,同时强调要高度重视工艺与装置研究、开发具有自主知识产权技术的重要性。     

PAN基炭纤维市场需求预测

通过对市场需求预测方法的分析,就国内PAN基炭纤维市场需求特点,对未来市场进行了定性和定量预测.     

我国PAN基炭纤维发展的对策

回顾我国过去发展炭纤维过程中存在的问题,作了针对性的分析,同时对将来发展的对策提出一些建议。     

空气氧化刻蚀提高PAN基炭纤维抗拉强度的研究

用空气氧化刻蚀（附浸渍预处理）的方法对通用级（类似T－300）PAN基炭纤维进行处理。以NaOH,HNO3,H2SO4,(H2SO4 KMnO4)为浸渍液，研究了直接空气氧化刻蚀中的氧化温度，氧化时间，浸渍液浓度等因素对炭纤维抗拉强度的影响。结果表明：在优化工艺条件下，炭纤维的抗拉强度可由3．73GPa提高到4．52GPa。     

PAN基炭纤维市场需求预测

通过对市场需求预测方法的分析,就国内PAN基炭纤维市场需求特点,对未来市场进行了定位和定量预测。     

聚丙烯腈(PAN)基炭纤维工业生产及应用

综述了炭纤维应用领域国内外市场,介绍炭纤维生产工艺过程及使用设备,指出当前国内炭纤维与国外产品的差距,并就当前我国炭纤维的发展现状给出了具体的应对措施,对发展我国炭纤维工业具有一定的指导意义。     

铜和硼化物对PAN基炭纤维的催化石墨化作用

将单质铜、硼酸、PAN基炭纤维进行混合研磨,经过石墨化炉高温处理,利用X射线衍射检测了铜和硼在热处理过程中的变化,研究催化剂的量和热处理温度对石墨化度的影响,结果显示炭纤维的石墨化度由25.6%提高到95.6%,表明铜和硼化物二元催化剂体系要比一元催化剂体系铜或硼更能显著地提高PAN基炭纤维的石墨化度,并完善炭纤维的石墨晶型。     

聚丙烯腈(PAN)基炭纤维工业生产及应用(续)

综述了炭纤维应用领域国内外市场,介绍炭纤维生产工艺过程及使用设备,指出当前国内炭纤维与国外产品的差距,并就当前我国炭纤维的发展现状给出了具体的应对措施,对发展我国炭纤维工业具有一定的指导意义。     

几种PAN基炭纤维的氧化特性研究

通过氧化实验，X射线衍射分析和扫描电子显微分析，初步研究了PNA基炭纤维的氧化特性，结果表明，PAN基炭纤维的氧化特性与其表面形貌和微晶参数密切相关，炭纤维表面的沟槽，坑洞越多，石墨微晶参数d002值越大，其氧化失重率越大，即抗氧化性越差。     

PAN基高模量炭纤维的制备及其性能的研究

本文采用高温热处理法制备ＰＡＮ基高模量炭纤维（ＰＡＮＨＭＣＦ）。着重研究了最高热处理温度和升温速率对ＰＡＮ基炭纤维（ＰＡＮＣＦ）宏观性能和微观结构的影响。实验结果表明：采用密闭式真空感应石墨化炉能够制备ＰＡＮＨＭＣＦ（抗拉模量＞４００ＧＰａ，抗拉强度≥２．５０ＧＰａ）；随着最高热处理温度的升高，ＰＡＮＣＦ的抗拉模量显著提高；欲制备ＰＡＮＨＭＣＦ（抗拉模量＞４００ＧＰａ），可以采用高温热处理法，最高热处理温度要在３０００℃左右；ＰＡＮＣＦ的抗拉强度随最高热处理温度的升高而降低；在一定范围内，加快升温速率可以改善ＰＡＮＨＭＣＦ的抗拉强度。本文还对ＰＡＮＣＦ的抗拉模量、抗拉强度和电阻率等性能变化的原因进行了讨论。     

Modification of polyacrylonitrile precursors for carbon fiber via copolymerization of acrylonitrile with ammonium itaconate

Ammonium‐modified polyacrylonitrile was prepared by free‐radical solution copolymerization of acrylonitrile (AN) with ammonium itaconate (AIA), and then it was spun into precursor fibers in this study. Effects of AIA and itaconic acid on the characteristics of the copolymers and precursor fibers were studied in contrast. It has been found that the ammonium modification could obviously increase the hydrophilicity of the copolymer. And in the spinning processes, modified copolymer can withstand higher total draw‐ratio of 12.6 folds, while unmodified copolymer only 8.5 folds. The void volume, fineness, tenacity, and elongation at‐break of the ammonium‐modified precursors are all improved and enhanced. WAXD test manifested that the modified precursors had higher degree of orientation. DSC test showed that the thermal properties of the modified and unmodified precursor fibers were almost the same. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 102: 2175–2179, 2006     

Modification of polypropylene fiber by radiation-induced graft copolymerization of acrylonitrile monomer

Modification of polypropylene fiber was carried out by graft copolymerization of acrylonitrile monomer using the preirradiation method. The influence of synthesis conditions (preirradiation dose, monomer concentration, temperature, draw ratio, and storage) on the degree of grafting was investigated. For all preirradiation doses, the degree of grafting was found to increase with the reaction time. The higher the preirradiation dose, the higher the degree of grafting was. The dilution of monomer with DMF showed peak maxima for the degree of grafting at 80% monomer concentration. Both the initial rate of grafting and the final degree of grafting were found to increase with an increase in the reaction temperature. An activation energy of 31.2 kJ/mol was found for the grafting reaction. The degree of grafting in the drawn fiber showed different behavior as compared to the undrawn fiber. The storage of the irradiated fiber at −4°C prior to the grafting showed a decrease in the degree of grafting initially for a period of 8 days, beyond which the degree of grafting remained constant. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1343–1348, 1998     

Effect of pH Value on the aqueous precipitation copolymerization of acrylonitrile and vinyl acetate

The aqueous precipitation copolymerization of acrylonitrile (AN) and vinyl acetate (VAc) with NaClO₃/NaHSO₃ redox initiation system is carried out continuously in a 10L pilot‐plant reactor. The effects of pH value on ionization equilibrium of NaHSO₃, polymerization rate, particle morphology, particle size and its distribution, molecular weight and its distribution have been investigated. It has been found that effective concentration of reductant H₂SO₃ increases with the decrease in pH value. On the other hand, deceasing pH value intensifies the coalescence among particles and then reduces diffusion rate of monomer and radicals into particles. Experimental data shows that the increase of pH value results in higher conversion. It indicates that pH value's effect on particle stability prevails its influence on effective concentration of the reductant. This conclusion is verified by the molecular weight, particle size, and particle morphology. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Graft copolymerization onto Tamarind Kernel Powder: Ceric(IV)‐initiated graft copolymerization of acrylonitrile

Tamarind Kernel Powder (TKP) is derived from the seeds of Tamarindus indica Linn., a common and most important tree of India. It is extensively used in cotton sizing, as a wet‐end additive in the paper industry, as a thickening, stabilizing, and gelling agent in the food industry. However, because of its fast biodegradability there is a need to prepare graft copolymers of TKP. The graft copolymerization of acrylonitrile (AN) onto TKP with ceric ammonium nitrate as a redox initiator in an aqueous medium has been studied. The reaction conditions were optimized to afford maximum percent grafting and percentage grafting efficiency of AN onto TKP, which was found to be 86% and 64%, respectively. Fourier Transform Infrared Spectrum of the grafted products showed an additional sharp absorption band at 2244 cm^?1 due to ? C?N stretching, thereby confirming the grafting of AN onto TKP. Scanning electron microscopy studies indicated change in contour of the polysaccharide on grafting and the thick polymeric coating of AN on the surface alongwith grafting of AN such that all the gap between polysaccharide particles have been closed. Thermal studies using thermogravimetric and differential gravimetric analyses confirmed that TKP‐g‐AN has overall high thermal stability than pure TKP. Reaction mechanism of grafting of acrylnitrile onto TKP is also proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Study of methyl‐methacrylate‐viscose fiber graft copolymerization and the effect of grafting on thermal properties

The graft copolymerization of methyl‐methacrylate onto viscose fibers was studied under photoactive conditions with visible light using Ce⁴⁺/Ti³⁺ combination as redox initiator in a limited aqueous medium. Polymerization conducted in the presence of light at 30 ± 1°C produced significant grafting, compared with that conducted in the dark under the same conditions. The % grafting, % total conversion, and % grafting efficiency were studied by varying time, monomer concentration, initiator concentration, and pH of the medium. The mechanism of polymerization and graft copolymer formation have been discussed. Characterization of the grafted fibers was done by Fourier transform infrared spectroscopy and scanning electron microscopy. The effect of % grafting on thermal properties was studied by thermogravimetric analysis. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 135–140, 1999     

AN-VAc-AMPS三元共聚合研究

介绍了丙烯腈 ( A N) -醋酸乙烯 ( VAc) (或丙烯酸甲酯 ( MA ) -2 -丙烯酰胺基 -2 -甲基丙磺酸 (英文缩写 AMPS)三元共聚合体系各组分竞聚率的测定方法 ,并比较三元共聚体系和二元共聚体系的AN /VAc竞聚率 ,对三元连续共聚进行了试验 ,讨论 A MPS含量与染色性的关系 ,聚合工艺条件与转化率关系。对聚合物溶液的流变性能及纺丝工艺 ,纤维的性能作了简单介绍。聚合及纺丝试验结果证明 ,以 AMPS为第三单体的三元共聚体系可纺性良好 ,所得纤维的物理性能、染色性能、吸水性和抗静电性均优于一般腈纶     

Kinetic study of copolymerization of acrylonitrile with ammonium acrylate

Ammonium acrylate was first used to successfully copolymerize with acrylonitrile. Kinetics of copolymerization of acrylonitrile with ammonium acrylate was investigated in a H₂O/dimethylsulfoxide (DMSO) mixture. The rate of copolymerization and particle size were measured. Kinetic equation of the copolymerization was obtained. Effect of copolymerization systems on monomer apparent reactivity ratios for acrylonitrile/ammonium acrylate copolymers was studied in comparison. Values of monomer apparent reactivity ratios were calculated by Kelen‐Tudos method. It has been found that monomer apparent reactivity ratios in water‐rich reaction medium [H₂O/DMSO>80/20] are approximately equivalent to those in aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H₂O > 80/20), apparent reactivity ratios are similar to those in solution polymerization system. With an increase in polarity of solvent, values of apparent reaction ratios both decrease. The values of apparent reaction ratios gradually tend to 1 with increase in the copolymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4679–4683, 2006     

不同共聚单体与丙烯腈的共聚合及其表征

采用四种共聚单体衣康酸(IA)、丙烯酸甲酯(MA)、丙烯酰胺(AM)、甲基丙烯酸甲酯(MMA)分别与丙烯腈(AN)进行自由基溶液共聚合,讨论了不同共聚单体对聚合反应动力学及所得纺丝原液的粘度的影响,对聚合物的热性能进行了DSC分析,考察了不同共聚单体对聚丙烯腈原丝热性能的影响。结果表明:AN/IA体系随IA含量的增加其反应速率明显下降;与其它单体相比AM更可能有效地降低聚丙烯腈原丝的预氧化温度,缓和放热,而衣康酸次之。同时,IA含量过大,会导致原丝预氧化时的降解。