聚合物浓溶液气液平衡估算的基团贡献法

评价了用聚合物浓溶液气液平衡估算的９种基团贡献法的预测模型,即ＡＳＯＧ,ＵＮＩＱＵＡＣ,ＵＮＩＦＡＣ,ＵＮＩＦＡＣ－ＦＶ,Ｆ－Ｈ,Ｅｌｂｒｏ－ＦＶ,ＧＫ－ＦＶ,ＧＣ－ＦｌｏｒｙＥｏＳ和ＧＣＬＦＥｏＳ的预测能力,建议使用ＵＮＩＦＡＣ－ＦＶ,Ｅｌｂｒｏ－ＦＶ,ＧＫ－ＦＶ,ＧＣ－ＦｌｏｒｙＥｏＳ（有待简化）４个模型来预测聚合物浓溶液的气液平衡。并展望了其今后的发展趋势。     

聚合物浓溶液气平衡估算的基团贡献法

评价了用聚合物浓溶液气液平衡估算的９种基团贡献法的预测模型,即ＡＳＯＧ,ＵＮＩＱＵＡＣ,ＵＮＩＦＡＣ,ＵＮＩＦＡＣ－ＦＶ,Ｆ－Ｈ,Ｅｌｂｒｏ－ＦＶ,ＧＫ－ＦＶ,ＧＣ－ＦｌｏｒｙＥｏＳ和ＧＣＬＦ ＥｏＳ的预测能力,建议使用ＵＮＩＦＡＣ－ＦＶ,Ｅｌｂｒｏ－ＦＶ,ＧＫ－ＦＶ,ＧＣ－ＦｌｏｒｙＥｏＳ（有待简化）４个模型来预测聚合物浓溶液的气液平衡。并展望了其今后的发展趋势。     

水悬浮法制备GF/PVC复合材料工艺研究

本文结合悬浮法制备ＧＦ／ＰＶＣ复合材料工艺的特点胆ＧＦ／ＰＶＣ复合的性能要求系统地研究了悬浮体系的配制及其影响因素,并对浸尖过程中ＧＦ／ＰＶＣ复合材料的树脂与纤维含量的控制及其规律、材料的脱水条件、ＰＶＣ树脂在纤维中的分布作了系统的研究     

美国Geon公司氯乙烯和聚氯乙烯生产技术

美国Ｇｅｏｎ公司前身是Ｂ．Ｆ．Ｇｏｏｄｒｉｃｈ公司的ＰＶＣ分部。Ｇｅｏｎ公司是美国第一，世界占第六位的ＰＶＣ生产公司，本文介绍该公司的概况，ＶＣＭ和ＰＶＣ的生产技术。     

科技信息

日本昭和电工开发了炭纳米纤维　　日本昭和电工成功地开发了纤维直径为 80ｎｍ的炭纳米纤维 (ＶＧＮＦ) ,并计划 2 0 0 2年生产 10ｔ。ＶＧＮＦ可称为是本公司早已生产的气相沉积炭纤维 (ＶＧＣＦ)和炭纳米管 (ＣＮＴ )中间领域的新材料。由于它具有松散材料与量子材料的特性 ,预计应用在燃料电池、树脂复合材料、金属复合材料等领域。本公司的主导产品ＶＧＣＦ的生产规模为年产 40ｔ ,主要应用在锂电池及其关连方面。本公司今后将ＶＧＮＦ同ＶＧＮＦ一起正式开发应用领域 ,计划到 2 0 0 5年此两种产品的产值达到 3 0～ 40亿日元。日本三洋…     

气相生长碳纤维形态及微观结构的研究

用扫描电子显微镜、透射电子显微镜、高分辨透射型电子显微镜、Ｘ射线能谱分析研究了ＶＧＣＦ的形态和微观结构特征,分析了制备工艺参数和产物结构的内在联系,发现一些新的现象并给出解释,为ＶＧＣＦ生长机理的确立提供了理论和实验依据。     

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。     

含碳材料的抗氧化行为和MgO质浇注料的抗氧化剂

用热重法分析了没有和有抗氧化添加剂 (Ａｌ,Ｓｉ,Ｂ4 Ｃ)的天然鳞片石墨 (ＦＧ)和经过挤压 (ＥＧ) ,涂层法 (ＣＧ) ,造粒(ＧＧ)改性处理后石墨的抗氧化行为 ,研究了含ＦＧ、ＥＧＣＧ、ＧＧ四种石墨的ＭｇＯ -Ｃ质浇注料的抗氧化性、流动性和力学性能。结果表明 ,添加有ＥＧ的ＭｇＯ -Ｃ浇注料的抗氧化性最好 ,12 0 0℃和 140 0℃空气中处理后的冷态抗折强度最高。添加Ａｌ,Ｓｉ,ＳｉＣ和Ｂ4 Ｃ ,添加量分别为 0 .1%的ＭｇＯ -Ｃ浇注料的抗氧化性研究表明 ,Ａｌ和Ｂ4 Ｃ复合添加时 ,ＭｇＯ -Ｃ浇注料的抗氧化性最好含碳材料的抗氧化行为和M…     

由工业氯化钙制备高纯碳酸钙微粉的研究

根据电子陶瓷行业的需要,进行了由工业ＣａＣｌ２制备高纯ＣａＣｏ３的过程研究,重点考究了ＣａＣｌ２Ｒ ＯＧＥ ＲＭＨＪＢＷＴ ＶＳ ＴＳＷＲ,ＴＦＦＵＣＦ ＵＴＫＫＧＪ ＷＸ ＮＴＣＥＲ     

高效助凝剂改性活化硅酸在净化水处理中的应用

高效助凝剂改性活化硅酸在净化水处理中的应用李玉华，谢红，赶东颖ＡＰＰＬＩＣＡＴＩＯＮＯＦＨＩＧＨＥＦＦＩＣＥＮＣＹＣＯＡＧＵＴＡＮＴＡＩＤＳＩＭＰＲＯＶＥＤＡＣＴＩＶＥＳＩＬＣＩＣＡＣＩＤＩＮＴＲＥＡＴＭＥＮＴＯＦＷＡＴＥＲ１前言活化硅酸属于无机高分...     

Effect of vapor‐grown carbon nanofibers on the sliding friction of natural rubber composites

The friction properties of vapor‐grown carbon nanofibers (VGCFs) reinforced natural rubber (NR) composites were investigated with the ball‐on‐plate sliding test. A mechanism was proposed on the basis of the viscoelastic properties, morphology and hardness of the composites, determined using dynamic mechanical analysis, optical microscopy, field emission scanning electron microscopy, transmission electron microscopy and a hardness‐testing device. The friction behavior of NR/VGCF composites showed three different stages: an increment trend at first stage, a decrement trend at second stage and a stable state at third stage. The peak values of friction coefficient were similar, and the peak shifted to a smaller cycle with increased VGCF content. The eventual friction coefficient decreased with increased VGCF content due to accelerated formation of abrasion patterns in the NR/VGCF composites. Moreover, the arranged VGCFs contributed to the self‐lubrication of NR/VGCF composites and the NR/20 wt% VGCF composite had the smallest friction coefficient. POLYM. COMPOS., 2011.© 2011 Society of Plastics Engineers     

Improved environmental stability,electrical and EMI shielding properties of vapor‐grown carbon fiber‐filled polyaniline‐based nanocomposite

An all polymeric electrically conductive thermoset adhesive resin system is prepared for future lightning strike protection applications. Polyaniline (PANI)‐based hybrid nano‐composite is prepared by incorporating high apparent‐density type vapor grown carbon fiber (VGCF‐H) as additional conductive filler. Electrical, mechanical and electromagnetic interference (EMI) shielding properties of PANI‐dodecylbenzene sulfonic acid (DBSA), and divinylbenzene (DVB) system are improved with addition of VGCF‐H. Different weight percentages of VGCF‐H in the PANI‐DBSA/DVB matrix, are studied, and their effect on composite's properties are investigated. Electrical conductivity up to 1.89 S/cm with the addition of 5 wt% VGCF‐H is achieved, which is almost 300% improvement compared with previous system. However, the maximum flexural modulus is obtained at 3 wt% of VGCF‐H. The change in the electronic structure of PANI with the addition of VGCF‐H is investigated using Fourier transform infrared (FT‐IR) analysis. Rheological study and Differential scanning calorimetry analysis were employed to show the effect of VGCF‐H concentration on curing profile of the nanocomposites. EMI shielding properties of the composite with and without VGCF‐H are measured in X‐band frequencies and compared. Composite with 5 wt% VGCF‐H has shown EMI shielding effectiveness about 51 dB in X‐band, which is higher than the composite without VGCF‐H (around 22 dB). POLYM. ENG. SCI., 59:956–963, 2019. © 2018 Society of Plastics Engineers     

Production and characterisation of vapour grown carbon fiber/polypropylene composites

Polymeric composites are widely used in the aircraft and automotive industries. Their high strength-to-weight ratio makes significant weight reduction possible. Beside this advantage, the polymer materials also offer a good corrosion resistance but the mechanical and electrical properties are not satisfactory. In order to increase these properties, vapour grown carbon fibers (VGCF) with high strength and metal-like electrical conductivity can be embedded in the polymeric matrix. To ensure a good adhesion between the fibers and the polymer matrix a functionalization of the chemically inert surface of the fibers is necessary.In the present research work oxygen-containing functional groups were introduced on the fiber surface through cold plasma treatment. Measurements of the fiber surface energy after plasma functionalization showed an enhancement of at least 50% of the initial value. The VGCF/PP composites with different amounts of VGCF were made through extrusion and injection molding. The results show that the degree of fiber surface functionalization and the fiber distribution and orientation in the polypropylene (PP) matrix may strongly influence the mechanical properties of the composite.     

Structural aspects of mechanical properties of iPP‐based composites. I. Composite iPP fibers with VGCF nanofiller

Nanocomposite fibers consisting of isotactic polypropylene (iPP) as a matrix filled with vapor grown carbon nanofibers (VGCF) have been prepared and their fine crystalline structure and mechanical properties characterized. The obtained results point out that the VGCF oriented along the fiber extrusion direction induce crystallization in the surrounding iPP matrix in a special way leading to the formation of oriented iPP α‐transcrystallite layers. The VGCF content and the draw ratio (DR) affect the textural properties of the composite material and lead to the formation of an anisotropic structure. The improvements of the mechanical properties of the composite fibers in both undrawn and drawn states are attributed to the VGCF aligning effect during extrusion, which produces highly oriented iPP crystalline structure, rather than to the reinforcing effect of the nanofibers. A new detailed scheme explaining the changes in tensile strength from the structural point of view is proposed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41865.     

Incorporation of graphene into polyester/carbon nanofibers composites for better multi-stimuli responsive shape memory performances

Graphene oxide was directly reduced into graphene in N-methyl-pyrrolidone with the assisted-dispersion of vapor grown carbon nanofibers (VGCF), resulting in a homogeneous dispersion of VGCF–graphene hybrid filler (VGCF–G). In the hybrid filler, VGCF served as effective stabilizers for graphene by adsorbing VGCF onto graphene through π–π interaction. Subsequently, the as-prepared VGCF–G was incorporated into a bio-based polyester (BE) to prepare BE/VGCF–G composites by solution blending. In the composites, graphene was complete exfoliated with the assisted-dispersion of VGCF. Simultaneously, graphene acted as “compatibilizer” to improve the dispersion of VGCF and enhance the interfacial adhesions. As a consequence, the binary combination of VGCF and graphene showed remarkable synergistic effects in improving the electrical conductivity and mechanical properties of the BE/VGCF–G composites. For example, at the filler content of 4.8 vol%, the electrical conductivity of BE/VGCF–G composite is about 4 orders of magnitude higher than BE/VGCF composite containing VGCF alone, and the ultimate stress and modulus of BE/VGCF–G composite is 58% and 45% higher than those for BE/VGCF composite. Furthermore, multi-stimuli responsive shape memory performances (electro-activated and infrared-triggered) of the composites were investigated. BE/VGCF–G composites showed a combination of higher shape memory recovery, stronger recovery stress and faster response, compared with BE/VGCF composites.     

Grafting of polymers onto vapor grown carbon fiber surface by ligand-exchange reaction of ferrocene moieties of polymer with polycondensed aromatic rings of the wall-surface

To improve the dispersibility of vapor grown carbon fiber (VGCF) in solvents, the grafting of copolymer containing vinyl ferrocene (VFE) onto the surface by ligand-exchange reaction between ferrocene moieties of the copolymer and polycondensed aromatic rings of VGCF was investigated. The copolymer containing VFE was prepared by the radical copolymerization of VFE with methyl methacrylate (MMA) using 2, 2′-azobisisobutyronitrole as an initiator. It was found that by heating of VGCF with poly(VFE-co-MMA) in the presence of AlCl₃ and Al powder, the copolymer was grafted onto the wall-surface: the percentage of grafting reached to 57.5%. It is considered that the copolymer was grafted onto VGCF surface by ligand-exchange reaction between ferrocene moieties of the copolymer and polycondensed aromatic rings of VGCF. In addition, carboxyl groups were successfully introduced onto VGCF wall-surface by the ligand-exchange reaction of 1,1′-dicarboxyferrocene with VGCF in the presence of AlCl₃ and Al powder. The carboxyl groups on VGCF were reacted with hydroxyl-terminated polymers to give the corresponding polymer-grafted VGCF. The polymer-grafted VGCF gave a stable colloidal dispersion in solvents for grafted polymer. The electric properties of composite prepared from polymer-grafted VGCF in solvent vapor were investigated.     

Si/VGCF复合材料的储锂性能

以纳米硅颗粒为原料,采用液相法制备了硅纳米粒子与气相生长碳纤维(VGCF)复合的材料(Si/VGCF)。考察了Si/VGCF制备工艺和VGCF的最佳含量,分别采用SEM和TEM表征了Si/VGCF材料形貌和晶体结构,测试和计算了材料电导、BET比表面积和孔尺寸数据。采用循环伏安、恒流充放电和交流阻抗等测试了Si/VGCF复合电极的电化学性能,并与其他碳材料进行了对比分析。结果表明,Si与VGCF形成了多级框架结构,丰富了离子和电子传输网络;同时发达的孔结构也缓解了Si粒子在嵌/脱锂过程中的体积效应,使电极活性材料的利用率和电化学稳定性显著提高。当m(Si)∶m(VGCF)为1:0.5时,Si/VGCF复合电极在500 mA/g的电流密度下,充放电循环100次后,可逆容量高达1470 mA·h/g。     

Mechanical and physical properties of epoxy composites reinforced by vapor grown carbon nanofibers

Epoxy/vapor grown carbon nanofiber composites (VGCF) with different proportions of VGCF were fabricated by the in situ process.The VGCFs were well dispersed in both of the low and high viscosity epoxy matrices, although occasional small aggregates were observed in a high viscosity epoxy of 20 wt.%. The dynamic mechanical behavior of the nanocomposite sheets was studied. The storage modulus and the glass transition temperature (T_g) of the polymer were increased by the incorporation of VGCFs.The electrical and mechanical properties of the epoxy-VGCFs nanocomposite sheets with different weight percentages of VGCFs were discussed. The results were that both had maximum tensile strength and Young’s modulus at 5 wt.% for both materials and reduced the fracture strain with increasing filler content. The electrical resistivity was decreased with the addition of filler content. Mechanical, electrical and thermal properties of low viscosity epoxy composites were resulted better than that of the high viscosity composites.     

Rheological behavior of (short) carbon fiber/thermoplastic composites. Part I: The influence of fiber type,processing conditions and level of incorporation

The aim of this work is to understand the influence of type of (short) carbon fibers, processing conditions and fiber incorporation level on the rheological behavior of carbon fiber/polypropylene (PP) composites. For this purpose, two types of fibers (sub‐micron Vapor Grown Carbon Fibers, VGCF, and ex‐PAN, PAN), three different extruder screw geometries and three different fiber incorporation contents were studied. The rheological characterization was performed by means of capillary and rotational rheometry, results being presented and discussed in terms of reinforcing capability in both shear (steady and oscillatory) and extensional flows. The results show that VGCF have a generally higher influence on the rheological behavior of the composites than the PAN fibers. However, because of their higher intrinsic rigidity, PAN fibers give rise to composites with better mechanical properties than the VGCF ones. It is also shown that the influence of the screw geometry on fiber damage and, consequently, on the behavior of the composites, is weak, fiber degradation occurring mainly in the compounding stage. The incorporation level has the expected influence, i.e., it produces gradual changes in all the properties considered in this study.     

Joule heat dependence of dynamic tensile modulus of polyimide-vapor grown carbon fiber nanocomposites under applied electric field evaluated in terms of thermal fluctuation-induced tunneling effect

To study mechanical and structural stabilities of polyimide (PI) and carbon filler composites by Joule heat, PI-vapor grown carbon fiber (VGCF) composites were fabricated by in situ polymerization to realize excellent dispersion of VGCFs in PI matrix. Adoption of VGCFs similar to rigid carbon fibers is the strategy to investigate the conductive mechanism theoretically in terms of thermal fluctuation-induced tunneling conduction. Dynamic tensile modulus and X-ray intensity under applied electric field were measured to investigate frequency-temperature dependence of the modulus by Joule heat in relation to the electron transfer mechanisms. Such simultaneous measurements for the mechanical and structural properties under electric field provided important information about the characteristic of polymer-filler composites. As the results, good heat resistance of PI-VGCF composites was clarified to be attributed to very few thermal fluctuation of PI chain arrangement in spite of collision between electrons flowed out from the VGCF gaps and atoms of PI chains.