静电纺PAA/PAN复合碳纤维膜的制备及其性能研究

采用不同结构的二酐、二胺单体设计制备了含对称结构单元和含不对称结构单元的聚酰胺酸(PAA),通过静电纺丝分别制备PAA、聚丙烯腈(PAN)、PAA/PAN复合物的纳米纤维膜(ENFs),将ENFs在空气中热稳定化后,在1 000℃的氮气气氛中碳化,制成不同前驱体的静电纺碳纳米纤维膜(ECNFs);研究PAA结构单元的对称性及PAA与PAN的复合对ENFs的热稳定化、碳化行为以及ECNFs导电性能的影响。结果表明:含不对称结构单元PAA的ENFs碳化收率较高,制备的ECNFs石墨微晶尺寸较大;将含不对称结构单元PAA与PAN复合时ENFs在1 000℃碳化时质量保持率达45%,且得到的ECNFs的石墨微晶尺寸与平均堆叠层数分别达1.69 nm和4.71,优于其他前驱体的ECNFs的微晶结构;PAA中的不对称结构单元及其与PAN的复合都有助于提升ECNFs的电导率,复合物的ECNFs的电导率最高可达9.08 S/cm;含不对称结构单元PAA与PAN形成了良好的协同碳化效应,可促使ECNFs的石墨晶粒的堆积和生长,提高ECNFs的导电性能。     

Preparation and characterization of polysiloxane–polyacrylates composite latices and their film properties

Gamma‐ray induced seeded emulsion polymerization of methyl methacrylate and butyl acrylate was carried out in the presence of a polymerizable polysiloxane seed latex, obtained by ring‐opening copolymerization of octamethyl cyclotetrasiloxane (D₄) and tetramethyl tetravinyl cyclotetrasiloxane (VD₄), catalyzed by dodecylbenzene sulfonic acid (DBSA). A series of polysiloxane seed latices with different molecular weights, vinyl contents and particle sizes was used. The conversion–time curve showed that the polymerization rate was accelerated significantly by the seed latex. The obtained composite latices also showed good storage stability, mechanical stability and high electrolyte resistance ability. By using transmission electron microscopy (TEM), the morphology of the composite latex particles was found to display a quite uniform fine structure. The graft polymerization reactions between the polymerizable polysiloxane and the acrylates were confirmed by Fourier‐transform infrared spectroscopy (FT‐IR) and the graft efficiencies were also studied. The influence of seed content, molecular weight, vinyl content of the polysiloxane and seed latex particles size on the mechanical performance, water absorption ratio, surface properties and transparency of the latex films was also investigated. It was found that the seed content and particles size greatly affect the mechanical performance, water absorption ratio and transparency of the latex films. Copyright © 2005 Society of Chemical Industry     

Electrochemical synthesis of polyacrylonitrile (PAN)–copper composite conductive film

Polyacrylonitrile–copper composite film was synthesized by electrochemical reduction of a swollen film made by blend solution of a polyacrylonitrile–copper(II) ion which was coated on a electrode surface. The morphological structure of this composite film in the cross section was measured by a scanning electronic microscope and it showed three composite layers: a densely deposited layer, a transition layer, and an undeposited layer. The deposited layer consisted of the copper element and gave a high conductivity (10⁰ S-cm⁻¹). In the transition layer, there was a great amount of a tree-shaped copper deposit, but no such deposit can be found in the undeposited layer. The experiment data showed that the conductivity of the film increases with increase of electrochemical reduction time and decreases with increase of ratio of nitrile group to the copper(II) ion. The viscosity of polyacrylonitrile-copper(II) ion solution is enhanced by a decrease of the ratio of the nitrile group to the copper(II) ion. © 1996 John Wiley & Sons, Inc.     

Preparation and properties of polysulfone–clay composite membranes

Porous membranes and dense films were prepared from polysulfone solutions in N‐methyl‐2‐pyrrolidone (NMP) containing different types and amounts of clay. Commercial clays supplied by Southern Clay, either unmodified (Cloisite Na) or organically modified (Cloisite 30B and Cloisite 93A), were used. The clay behavior in the organic solvent was dependent on the presence and type of the organic compatibilizer: Cloisite containing Na ions did not swell in NMP, whereas those with the organic compatibilizer swelled, though to a different degree. Electron microscopy observations were made to examine the clay dispersion in the membrane structure. At variance with Cloisite Na and Cloisite 93A formed microaggregates, Cloisite 30B yielded nanostructures composed of both single sheets and well‐ordered multilayer silicate clusters, which were characterized by an interlayer distance higher than that of the neat clay. The increase in the distance between the layers of Cloisite 30B was related to the formation of intercalated nanocomposites, whereas the presence of single sheets well distributed in the polymer matrix supported the occurrence of delaminated nanocomposites. The intercalation of the polymer into clay layers was confirmed with wide‐angle X‐ray diffractometry. The addition of Cloisite 30B to the casting solution influenced the phase‐separation process in the coagulation bath. Therefore, by the variation of the layered‐silicate concentration in the casting solution, membranes with different morphological structures and ultrafiltration properties were obtained. Cloisite 30B was also found to improve the wettability and mechanical properties of dense films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3637–3644, 2007     

Relationship between structures of polyacrylonitrile (PAN)–copper gradient composite film and electrochemical-reaction conditions

In this article, the relationship between the morphological structure and electrochemical conditions, the crystal structure in the electrochemical deposited phase, and the thermal properties of polyacrylonitrile (PAN)–copper gradient composite films (GCF) were studied. The results showed that the morphology of the GCF depended very much on the electrochemical conditions used in the reactions. The percent area of the deposited phase on the cross section of the GCF decreases with increases of the predrying time of the solution coated on the cathode, the power voltage, and the temperature in the electrochemical reactor. According to the data of a differential scanning calorimeter and a scanning electronic microscope, PAN chains are physically crosslinked by a deposited phase. Under the electrochemical conditions used in this article, the components of PAN are not affected by the electrochemical reactions. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1159–1165, 1998     

Preparation and characterization of polysiloxane–polyacrylates composite lattices by two seeded emulsion polymerization and their film properties

Gamma ray‐induced seeded emulsion polymerization of methyl methacrylate and butyl acrylate was carried out in the presence of polymerizable polysiloxane seed latex, which was obtained by the ring‐opening copolymerization of octamethyl cyclotetrasiloxane (D₄) and tetramethyl tetravinyl cyclotetrasiloxane(VD₄) catalyzed by dodecylbenzene sulfonic acid (DBSA). After the first seeded polymerization, 3‐methacryloxylpropyltrimethoxylsilane (MPS) was added for the second seeded polymerization. The conversion–time curve showed that the first seeded polymerization rate was accelerated much by the polysiloxane seed latex. The final composite lattices also showed good storage stability, mechanical stability, and high electrolyte resistance ability. The morphology of the composite latex particles was found to be a quite uniform fine structure by transmission electron microscopy (TEM). The graft of polyacrylates onto polysiloxane and hydrolysis of MPS were confirmed by Fourier transform infrared (FT‐IR) spectroscopy. The mechanical performance, water absorption ratio, surface properties, and transparency of the latex films were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1406–1411, 2007     

有机无机复合固态电解质的制备及电性能研究

本文以聚环氧乙烯(PEO)为基体,添加无机固态电解质颗粒(LA),通过超声分散法制备出电化学性能优异且具有自支撑柔性的有机无机复合固态电解质膜,并组装扣式电池测试电性能,包括离子电导率、电化学窗口、锂离子迁移数及界面阻抗,得出LA对电解质膜电性能的影响.     

功能化纳米纤维素复合PLA/PBAT薄膜的制备及性能

以γ-氨丙基三乙氧基硅烷(KH550)为改性剂对纤维素纳米纤维(CNF)进行功能化改性，并用聚丙二醇(PPG)对改性后的CNF进行包覆，制备了CNF-PPG纳米粒子。将其作为填料加到聚乳酸(PLA)/聚己二酸/对苯二甲酸丁二醇酯(PBAT)聚合物基体中，用溶液浇铸法制备了PLA/PBAT/CNF-PPG复合薄膜。通过FTIR、XPS、SEM、DSC、TG对薄膜进行了表征，探讨了PLA与PBAT的质量比及CNF-PPG纳米粒子的添加量对复合薄膜机械强度、热稳定性、阻隔性能的影响。结果表明，PLA/PBAT薄膜比纯PLA薄膜具有更高的韧性和热稳定性；当m(PLA)∶m(PBAT)=90∶10、CNF-PPG纳米粒子用量(以PLA和PBAT的质量为基准，下同)为10%时，PLA/PBAT/CNF-PPG(90/10/10)复合薄膜的拉伸强度达到(33.38±0.64) MPa，断裂伸长率为39.97%±0.67%；复合薄膜最终降解温度从纯PLA膜的394℃提高到435℃；复合薄膜的水蒸气和氧气透过系数分别为4.98×10^–14 g·cm/(cm²·...     

砖红壤/天然胶乳复合胶膜的制备与性能研究

研究了砖红壤对天然胶乳的补强作用。将砖红壤原土中的细粒子制成悬浮液,加入预硫化天然胶乳中,制备砖红壤/天然胶乳复合胶膜,并分析胶膜的结构特性、力学性能和交联密度等。结果表明,砖红壤粒子在橡胶相中分散均匀,砖红壤细粒子对天然胶乳具有优异的补强效果,硫化胶膜的拉伸强度和撕裂强度均有大幅度的提高,这是由于砖红壤的加入能够促进橡胶的硫化,砖红壤中的氧化铁能够与橡胶分子链中的不饱和双键结合,提高了砖红壤在橡胶相中的分散性,使二者形成良好的界面结合。     

Anomalous electrical transport properties of PVA–Ag composite films below room temperature

The direct current (dc) and alternate current (ac) electrical transport property of polyvinyl alcohol–silver (PVA–Ag) composites has been investigated within a temperature range of 77 ≤ T ≤ 300 K and in the frequency range of 20 Hz to 1 MHz in the presence as well as in the absence of a transverse magnetic field up to 1 T. The dc conductivity follows variable range hopping model. The magnetoconductivity of the samples undergoes a change from negative to positive values with the incorporation of Ag in PVA matrix, which can be interpreted by the dominancy of the forward interference effect prevailing over the wave function shrinkage effect. The ac conductivity follows a power law of frequency, whereas the temperature dependence of frequency exponent “s” can be explained by correlated barrier hopping model. The dielectric behavior of the samples has been governed by the grain and interfacial grain boundary resistance and capacitance. Two activation behaviors are observed from the analysis of grain and interfacial grain boundary contributions. POLYM. COMPOS., 33:1941–1950, 2012. © 2012 Society of Plastics Engineers     

Bithiazole‐containing polymeric complex and PVA composite film: Preparation and magnetic properties

Two novel bithiazole‐containing polyamides, DClAI and DTTPA, and their complexes were synthesized by condensation and complexation. Novel homogeneous composite films were prepared by in situ blending these complexes with polyvinyl alcohol. These polymeric complexes and composite films were characterized by FTIR. The magnetic properties of the complex and its related composite film were measured using a physical property measurement system. It was found that the properties of films are similar to those of their related polymeric complexes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1264–1270, 2004     

Preparation,characterization, and optical properties of a chitosan–anthraldehyde crosslinkable film

A novel chitosan–anthraldehyde derivative film was prepared by the reaction of 79% deacetylated chitosan with 9‐anthraldehyde with a hydrogel by a solution casting method. The prepared chitosan derivative film was confirmed by ultraviolet–visible absorption spectroscopy of the absorption peak at 266 nm due to the presence of an anthracene ring. The crosslinking reaction showed significant changes in the Fourier transform infrared spectrum of the chitosan derivative film. The characteristic peak of CH?N stretching bands at 1610 cm^?1 confirmed the formation of a Schiff base after the reaction of chitosan with 9‐anthraldehyde. The film was evaluated by X‐ray diffraction, scanning electron microscopy, photoluminescence spectroscopy, and second harmonic generation (SHG). The nature of the crystallinity of the chitosan derivative from X‐ray diffraction analysis confirmed that the film may have had nonlinear optical properties. The chitosan derivative showed a redshifted emission maximum because of the electron‐rich polymer main chain. No reabsorption of the second harmonic signal and no resonance enhancements were noticed during the SHG study; this indicated that the chitosan derivative possessed SHG ability. Overall, the chitosan derivative film opens new perspectives for optical material for biomedical applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Structural and electrical behavior of polyacrylonitrile-polypyrrole composite film

Polyacrylonitrile-polypyrrole composite films were prepared by a vapor phase technique. The films obtained by this method have high conductivity and good mechanical properties. Growth of polypyrrole on the surface of polyacrylonitrile was investigated by electron microscopic studies. Electrical properties of composite films were investigated as a function of FeCl₃ content as well as polypyrrole uptake. The current-voltage characteristic suggest an ohmic conduction. The conductivity of these composite films was measured as a function of temperature yielding an activation energy of 0.16 eV.     

贻贝启发蒙脱石-银/聚乳酸抗菌膜的制备及其性能

受自然界贻贝粘附现象的启发,将聚多巴胺(PDA)作为二次反应平台,绿色合成了一种纳米银(Ag NPs)负载蒙脱石(MMT-Ag NPs)复合抗菌颗粒,通过溶剂挥发法将聚乳酸(PLA)和MMT-AgNPs共混,制备了复合抗菌膜(PLA/PDA/MMT-AgNPs)。利用FTIR、XRD、TEM和TGA对MMT-Ag NPs的物质组成、物相结构、微观形貌、热稳定性进行了测定。对所制备的PLA/PDA/MMT-AgNPs复合抗菌膜的微观形貌、物理性能和抗微生物活性进行了考察。结果表明:PDA成功地对MMT进行了改性,PDA改性的MMT仍保持原来的物相结构,Ag NPs在MMT表面成功负载,负载的质量分数达到12.2%。PLA/PDA/MMT-AgNPs复合抗菌膜的拉伸强度显著增强,与PLA膜相比最高增长了32.6%。由于Ag NPs极强的抗菌作用,仅添加少量MMT-Ag NPs的复合抗菌膜就对大肠杆菌和金黄色葡萄球菌表现出了优异的抗菌作用,抑菌率均达到了95%以上。     

Preparation,characterization, and electrical properties of ZSM‐5/PEG composite particles

ZSM‐5/PEG composites were synthesized by a simple solution method with polyethylene glycol (PEG) and H‐ZSM‐5 zeolite (Si/Al = 11.4). The obtained composites were characterized using X‐ray powder diffraction and Fourier transform infrared spectroscopy. The obtained results indicated that the ZSM‐5 was physically combined with PEG. The thermal properties and thermal stability were investigated by thermogravimetric and differential thermal analyses. In situ electrical conductivity was used to follow‐up the changes in the electrical conductance during the heating of the ZSM‐5/PEG composite. It was found that ZSM‐5 is able to effectively enhance the electrical conductivity of PEG. The results showed that the obtained weight loss during the composite decomposition to charcoal is accompanied by a decrease in the electrical conductivity. Moreover, the removal of the formed charcoal is associated with an electrical conductivity increase. Calcining the ZSM‐5/PEG composite having a content of 30% results in many effects on the structural, textural, and electrical properties of the obtained products. POLYM. COMPOS., 35:1160–1168, 2014. © 2013 Society of Plastics Engineers     

电火花加工用铜基镍–氧化铝复合电极的制备及性能

以纯铜棒为基体,采用复合电镀技术制备了Ni–Al2O3复合电极。镀液组成和工艺条件为:Ni SO4·6H2O 250~300 g/L,Ni Cl2·6H2O 40~50 g/L,Al2O3 10~60 g/L,H3BO3 35~40 g/L,十二烷基硫酸钠0.05 g/L,p H 3~4,阴极平均电流密度2~6 A/dm2,温度30~70°C,时间3 h。分析了镀液中Al2O3颗粒添加量、温度和阴极电流密度对Ni–Al2O3复合镀层Al2O3含量、均匀性和显微硬度的影响。分别以Ni–Al2O3复合电极和纯铜电极为工具,对W7Mo4Cr4V2Co5高速钢进行电火花加工(EDM)试验。在Al2O3添加量30 g/L、阴极电流密度3 A/dm2、温度50°C的条件下,所得镀层厚度为100μm,Al2O3颗粒体积分数为14.48%,显微硬度为434.72 HV,综合性能最佳。Ni–Al2O3复合电极在EDM试验中的相对质量损耗约为纯铜电极的1/5,抗电蚀性更优。     

大豆蛋白纳米二氧化钛复合膜的制备及性能研究

以十二烷基磺酸钠为分散剂,采用超声波分散技术将不同掺杂比的纳米二氧化钛引入大豆蛋白成膜液中,用流延法制得分散均匀的纳米复合膜.随着纳米二氧化钛用量的增加,复合膜的抗拉强度和断裂伸长率先增大后减小,透湿性和透氧性则按先减小后增大的趋势变化.当纳米二氧化钛质量为大豆蛋白1/200时,复合膜的抗拉强度和断裂伸长率都达到最大值,分别比大豆蛋白膜提高了106%和112%;而复合膜的透氧系数则最低,比大豆蛋白膜低了近7.5倍.     

Investigation of structure of polyacrylonitrile–polyprorole composite film

The structure of polyacrylonitrile–polypyrrole composite film, prepared using pyrrole in vapor and FeCl₃ as catalyst, was investigated using IR spectroscopy, DTA/TGA, and resistivity measurements. The films showed improved thermal stability and electrical conduction. The strength of the composite film decreased as compared to pure PAN and the growth structures of polypyrrole could be seen.