电纺PLLA/PCL/PEG共混纤维膜的结构及性能

采用静电纺丝技术制备了聚乳酸（PLLA）/聚己内酯（PCL）/聚乙二醇（PEG）共混纤维膜,考察了溶剂体积比、共混物共混质量比、溶液浓度对电纺纤维形貌的影响,研究了共混纤维膜的热稳定性、结晶性、力学性能及亲水性。结果表明加入PEG有效提高了共混纤维膜的热稳定性和结晶性,提高了共混纤维膜的拉伸强度、弹性模量和亲水性能。     

纳米粒子形貌对聚吡咯/LDPE纳米复合材料直流介电性能的影响

为了研究不同微观形貌的纳米导电粒子对低密度聚乙烯(LDPE)直流介电性能的影响,本文采用软模板法制备了直径约100 nm的聚吡咯(PPy)纳米球和纳米线,并将其与LDPE熔融共混制备得到了PPy/LDPE纳米复合材料。利用扫描电子显微镜(SEM)观察了PPy纳米粒子的微观形貌及其在PPy/LDPE纳米复合材料中的分散结构,并测试了复合材料的结晶度、空间电荷分布、介电谱、不同温度下的直流电导电流及直流击穿强度等介电性能。结果表明：PPy纳米粒子的加入可以提高LDPE的结晶度,抑制LDPE中空间电荷的累积,降低其相对介电常数、直流电导电流和直流击穿强度,其中PPy纳米球的加入可在不同温度下使LDPE直流电导电流降低1个数量级以上,而对其直流击穿强度的影响较小,并且在较高温度下可将LDPE的直流击穿强度提升4.4%。PPy纳米球对LDPE绝缘材料直流介电性能的改善效果要优于PPy纳米线。     

聚吡咯/还原氧化石墨烯导电填料的制备及应用

将氧化石墨超声分散,在水合肼的作用下制备了在水相条件下稳定分散的还原氧化石墨烯(RGO);以十六烷基三甲基溴化铵(CTAB)为模板剂,RGO为掺杂剂,吡咯单体为原料,六水合三氯化铁(FeCl_3·6H_2O)为引发剂聚合制备聚吡咯/还原氧化石墨烯(PPy/RGO)导电复合材料。利用傅里叶红外光谱、X射线衍射和透射电子显微镜等手段对复合材料的理化性质进行表征,结果表明线状PPy成功聚合在RGO表面;热重分析和电导率测试结果显示,复合材料相对于PPy具有更高的热稳定性和电导率,电导率可达14S/cm。将PPy/RGO复合材料水性聚氨酯乳液制成复合涂层,考察了涂层的抗静电性能,发现PPy/RGO复合材料具有更低的逾渗阈值。     

壳聚糖/聚乙烯醇复合纳米导电纤维的制备及性能表征

以壳聚糖(CS)、聚乙烯醇(PVA)和纳米石墨粉(G)为原料,利用静电纺丝技术分别制备了壳聚糖/聚乙烯醇共混纳米纤维及壳聚糖/聚乙烯醇/纳米石墨粉复合纳米纤维,采用原位聚合法在纤维表面聚合导电聚合物聚苯胺,得到具有优良导电性能的聚合CS/PVA和聚合CS/PVA/G复合纳米纤维。通过扫描镜、X射线衍射、红外光谱等测试手段对纤维的形貌和结构进行表征。结果表明,聚苯胺均匀包覆在经原位聚合的复合纳米纤维表面,提高了纤维的导电性能,纳米石墨粉与聚苯胺形成插入化合物进一步提高了纤维的导电性能。     

滴胶/炭黑心电电极的制备及性能表征

以高透明水晶胶A胶,B胶和纳米级炭黑为反应原料,采用共混-模压成型法制备了滴胶/炭黑纳米复合导电材料。利用FT-IR、TGA和SEM对该复合材料组分、结构和形貌进行表征,并尝试将该导电复合材料与纯棉无纺布结合制备滴胶型心电电极,同时考察了该类心电电极的导电性能。结果表明,通过共混-模压成型法成功制备了纳米炭黑分散均匀的导电滴胶/炭黑纳米复合材料,其弹性模量为2.45 MPa,电导率为0.399μS/cm,制备的滴胶/炭黑心电电极电导率为7.051μS/cm,具有优异的导电性能,能够采集到稳定的人体心电信号,心电波谱单元清晰、稳定,信噪比高,可满足市场化应用要求。     

热定型工艺对PVA/PEDOT∶PSS共混纤维结构和性能的影响

将PVA水溶液与PEDOT∶PSS水分散液共混,制备出混合均匀的PVA/PEDOT∶PSS混合纺丝液,通过改变湿法纺丝后处理工艺中的热定型制备出不同热定型温度下的PVA/PEDOT∶PSS共混导电纤维。探究了热定型工艺对共混纤维结构和性能的影响,并分析了影响机理。借助红外光谱分析仪(FT-IR),X射线衍射仪(XRD),高阻计,电子单纤维强力仪和扫描电子显微镜(SEM)对共混纤维进行测试表征。结果表明:热定型温度对共混纤维的结晶性能,导电性能,拉伸力学性能,表面形貌及热稳定性均有一定程度的改善。随着热定型温度的升高,纤维大分子链的结晶程度逐渐完善,形成择优取向不明显的多晶结构;纤维电导率逐渐提高;纤维的拉伸断裂强度逐渐升高,拉伸断裂伸长逐渐降低;纤维表面的沟槽数量减少,沟槽的均匀性及平行度提高,纤维表面形貌得到改善。     

天然纤维素/聚丙烯腈抗菌纳米纤维的制备与表征

为了拓展天然纤维素材料的应用,在综合国内外对天然纤维素材料、纳米材料和抗菌材料相关研究的基础上,首先,利用LiCl/二甲基乙酰胺(DMAC)溶剂体系配置了不同共混比例的天然纤维素/聚丙烯腈纺丝液,采用静电纺丝技术制备了纤维素/聚丙烯腈纳米纤维。然后,用铜氨溶液对纳米纤维进行了抗菌处理,制备了具有一定抗菌功能的纤维集合体。最后,采用SEM观察不同共混比例下纳米纤维的微观形貌;采用TG和DSC表征其热性能;采用FTIR和表面接触角测量仪表征共混后纳米纤维的化学组成和亲水性的变化;采用振荡法测定纳米纤维的抗菌性能。结果表明:通过静电纺丝技术可制得直径在200~400nm范围内的纤维素/聚丙烯腈纳米纤维。随着纤维素含量的提高,纳米纤维的表面越来越粗糙,粘连愈加严重,且直径离散度也变大。当纤维素与聚丙烯腈的共混质量比大于75∶25时,纤维的直径标准偏差由纯聚丙烯腈纤维的100nm以下变为150nm以上。纤维素/聚丙烯腈纳米纤维具有良好的热性能,与纯纤维素纳米纤维相比热稳定性有一定提高,当纤维素与聚丙烯腈的共混质量比为25∶75时热稳定性最好。纤维素/聚丙烯腈纳米纤维的亲水性优于普通医用纱布的。经过铜氨溶液抗菌处理的纳米纤维具有良好的抗菌性能,对金黄色葡萄球菌和大肠杆菌的抑菌率分别为82%和75%。     

聚吡咯/蒙脱土纳米复合材料的表征与复合机理

以水为介质，用化学氧化就地吸附聚合法(in：situpolymerization)制备了聚吡咯(PPy)／蒙脱土(MMT)纳米复合导电材料。利用红外光措(FT-IR)、热失重(TGA)、X射线衍射(XRD)和四探针技术表征了材料的组成、结构和性能。结果表明PPy键已进入MMT内层空间，二者达到了纳米级复合。纳米复合材料的电导率已达50S／cm。     

纺丝体系温度对PVA/PEDOT∶PSS共混纤维性能的影响

将聚乙烯醇(PVA)水溶液与聚3,4-乙撑二氧噻吩∶聚对苯乙烯磺酸根阴离子(PEDOT∶PSS)水分散液共混,在不同的纺丝体系温度下,通过湿法纺丝方法制备出PVA/PEDOT∶PSS共混纤维。在制备出PVA/PEDOT∶PSS共混纤维的基础上,探究了纺丝体系温度对共混纤维化学结构、表面形貌、导电性能及拉伸力学性能的影响。借助扫描电子显微镜、红外光谱分析仪、高阻计和电子单纤维强力仪对共混纤维进行测试表征。结果表明:随着纺丝体系温度的升高,制备出的PVA/PEDOT∶PSS共混纤维的导电性能逐渐升高,电导率由1.55S/cm增加到2.39S/cm;制备出的PVA/PEDOT∶PSS共混纤维表面形貌有一定程度改善,纤维表面沟槽数量减少;制备出的PVA/PEDOT∶PSS共混纤维的拉伸强度逐渐升高,断裂伸长逐渐降低。     

纤维素基导电水凝胶的合成及其结构性能表征

以离子液体(氯化-1-丁基-三甲基咪唑,BMIMCl)溶解微晶纤维素(MCC),以N,N-亚甲基双丙烯酰胺作为交联剂形成的纤维素水凝胶为基体,同时吡咯(Py)作为导电聚合物单体,制备了纤维素基导电水凝胶。对MCC/PPy复合导电水凝胶的化学结构和表面形貌进行了表征,研究了该导电水凝胶的导电性、溶胀性能和热稳定性。结果表明,PPy与MCC水凝胶形成了具有半互穿网络结构的导电水凝胶,该水凝胶表面呈蜂窝状;其电导率数量级可达10-4~10-3,且对甲苯磺酸钠掺杂可大幅提高其电导率;随着MCC浓度的增加,纤维素水凝胶的平衡溶胀率呈下降趋势,所得导电水凝胶的溶胀率比纯纤维素水凝胶的溶胀率略有下降,但仍能维持500%的水平;此外,该导电水凝胶的热稳定性较纯MCC水凝胶有所下降。     

聚吡咯/磷酸铁锂复合正极材料的制备与表征

采用化学氧化法, 以吡咯为单体、 三氯化铁为氧化剂、 苯磺酸钠为掺杂剂在磷酸铁锂颗粒表面进行原位聚合, 制备了聚吡咯/磷酸铁锂(PPy/LiFePO₄)复合材料。用FTIR、 XRD和SEM对PPy/LiFePO₄复合材料进行了结构与形貌表征。用电化学工作站和充放电测试系统对复合材料的电化学性能进行了表征。结果表明: PPy/LiFePO₄复合材料作锂二次电池正极具有良好的充放电循环性能。当PPy质量分数为17%, 充放电电流为0.1 mA时, PPy/LiFePO₄复合材料最高放电比容量达163 mAh·g^-1, 50次循环之后放电比容量仍为初始时的94.9%; 与LiFePO₄相比, 当PPy的含量适当时, PPy/LiFePO₄复合正极材料的放电比容量会有明显提高。PPy的加入提高了LiFePO₄的电子电导率, 从而提高了活性物质有效利用率, 因此PPy/LiFePO₄复合材料的比容量和循环性能均得到了提升。     

Synthesis and conductive properties of polypyrrole nanocomposites

This paper studies the impact on the different surfactants and capacity of the oxidant for the synthesis of polypyrrole (PPy). The soluble PPy has also been studied. PPy was characterized mainly from the surface morphology, Fourier transform infrared spectroscopy, and conductivity sigma. First, using cetyltrimethylammonium bromide (CTAB) as the surfactant doped in an acid doping environment and without using ammonium persulfate (APS) as an oxidant, we determined the different capacities of the oxidant to synthesize the PPy. Scanning electron microscopy, Fourier transform infrared spectroscopy, and a four-probe conductivity meter were used to characterize the PPy. The acid doping conductivity was found to be 25 S/cm higher. Then, the solubility of polypyrrole was studied by doping with sodium dodecyl benzene sulfonate (SDBS), polyethylene glycol (PEG), and poly(styrene sulfonate) (PSS), proceeding the above-mentioned characterization.     

Synthesis and characterization of conductive core-shell polyacrylonitrile-polypyrrole nanofibers

Nonwoven polyacrylonitrile-polypyrrole (PAN-PPy) core-shell nanofiber mats were prepared through the growth of PPy layers on electrospun PAN nanofibers via a two-step vapor-phase polymerization, i.e., the wet-coating of ferric tosylate (FeTos) oxidants on PAN nanofibers followed by exposure to pyrrole monomers in the gas phase. Under the conditions ([FeTos] = 10 wt%, reaction time = 15 min, temperature = 15 degrees C), the PPy polymerization procedure led to both a uniform coating over the PAN surface with an average thickness of 18 nm and cross-linkages among the nanofibers without a noticeable change in the highly porous nanofibrous structures. The oxidant concentration and polymerization time were found to be key parameters for achieving a good nanostructured core-shell fiber mat. FT-IR, XPS, XRD and conductivity measurements confirmed the synthesis of Tos-doped PPy with some degree of crystallinity and a high conductivity.     

Polypyrrole/poly(vinyl alcohol-co-ethylene) nanofiber composites on polyethylene terephthalate substrate as flexible electric heating elements

Polypyrrole/poly(vinyl alcohol-co-ethylene) (PPy/PVA-co-PE) nanofiber composites on polyethylene terephthalate (PET) substrates were prepared using spray coating technique and in situ polymerization process. The electric heating behaviors of composites were investigated as functions of the amounts of nanofiber and PPy. It was observed that, the electrical resistivity of composites decreased significantly with increasing nanofiber and PPy contents. Scanning electron microscope images and infrared spectrum studies confirmed the formation of well dispersed network-like structure of PPy/PVA-co-PE nanofibers on PET substrate. Furthermore, maximum temperature attained at a given applied voltage for the composites could be well controlled by changing nanofibers and PPy amounts. PPy/PVA-co-PE nanofiber/PET composites exhibited excellent electric heating performance in aspects of rapid temperature response, long retaining behavior, thermal and operational stability. The incorporation of PPy on PVA-co-PE nanofibers/PET nonwoven substrates resulted in high conductivity and enhanced heating behavior, which have potential to be used as efficient electric heating elements.     

纳米纤维素-聚吡咯/天然橡胶柔性导电弹性体的制备与性能

以纤维素纳米纤丝（Cellulose nanofibrils,CNFs）为生物模板,将聚吡咯（Polypyrrole,PPy）原位聚合在CNFs表面,再将CNF-PPy复合物均匀分散到天然橡胶（Natural rubber,NR）弹性基体中,制备了具有高柔韧性的纳米纤维素-聚吡咯/天然橡胶（CNF-PPy/NR）导电弹性体。结果表明：CNFs可协助PPy在NR基体中形成三维导电网络结构,并提高弹性体的力学性能和导电性能,有效降低其逾渗阈值。当添加质量比为5%（以橡胶质量为基准,下同）的CNF和20%的PPy时,CNF-PPy/NR的拉伸强度可达（8.97±0.92）MPa,分别约为PPy/NR及纯NR的1.56倍和9.54倍,电导率可达（0.134±0.063）S/m;在0.3 A/g的电流密度下,比电容可达96 F/g,并在1.0 A/g电流密度下循环充放电1 200次后,比电容仍可保持其初始值的72%。此导电弹性体具有良好的力学强度和电学性能,有望应用于柔性有机电子器件领域。     

Ferromagnetic conductive polypyrrole doped with water-soluble ferrocene derivative

In this paper, we report synthesis and characterization of polypyrrole (PPy) doped with a new water-soluble ferrocene derivative of p-ferrocenyl benzene sulfonic acid (BSAFc). The ferromagnetic conductive PPy powder was obtained by chemical polymerization. XPS and FT-IR were used to clarify the structure of PPy powder and confirm the existence of ferrocene group in the PPy powder. A complete understanding of the electronic structure of iron in PPy powder was achieved by Mössbauer spectrum measured at room temperature, which indicates that ⁵⁷Fe in the PPy powder is in the low-spin electronic structure of trivalence. The PPy powder exhibited an electrical conductivity of about 10⁰ S/cm at room temperature, a coercive force of 20 Oe and saturation magnetization of 1.76 emu/g at low temperature of 1.8 K. Thermogravimetric analysis (TGA) showed that the PPy powder had the same thermostability as normal PPy. The electro-active PPy freestanding film was also synthesized by doping with the new water-soluble ferrocene derivative via electrochemical polymerization, which is significant for developing the application of the PPy film in secondary battery, membrane electrode and so on.     

聚氨酯/富马酸二甲酯磺酸钠复合物的离子导电性和形态研究

采用溶液聚合的方法合成了线型聚醚聚氨酯（PU），以其作为基体，与富马酸二甲酯碘酸钠（SDMFNa)复合制得了一系列新型的聚合物固体电解质。利用傅立叶变换拉曼吸收光谱法（FT－Raman)、差示扫描量热法（DSC）、原子力显微镜（AFM）和交流复阻抗谱（IA）对该体系的化学结构、微观形态和离子导电性能进行了研究。结果表明，当有机钠盐的用量为[EO]/[Na^ ]=24时，体系的相容性最好，玻璃化转变温度（Tg)达到极大值，随着盐含量的增加，SDMFNa会聚集析出，体系的Tg下降。复合物的电导率随着温度的升高而升高。在所研究的盐浓度范围内，该聚合物固体电解质的电导率存在一最大值。     

Characterization of conductive composite films based on TEMPO-oxidized cellulose nanofibers and polypyrrole

Abstract  

In this article, conductive composite films based on TEMPO-oxidized cellulose nanofibers (TOCN) and polypyrrole (PPy) were synthesized in situ by a Chemical Polymerization Induced Adsorption Process of pyrrole on the surface of TOCN in aqueous medium. Resulting composite films were investigated by X-ray photoelectron spectroscopy, scanning, and transmission electron microscopy, N₂ gas adsorption analysis, thermogravimetric analysis, mechanical tests, and conductivity measurements in the ambient air. Our results showed a stable, flexible, and highly electrically conductive composite film in which PPy nanoparticles coated the surface of the TOCN network. In addition, the advantage in using the famous material, TOCN, is clearly due to the presence of carboxylate (COOH/COO⁻Na⁺) and hydroxyl (OH) moieties on the surface of TOCN. These reactive moieties could enhance the adsorption process of positively charged PPy backbone during polymerization. TEM observations demonstrated the formation of a PPy coat along the surface of the cellulose nanofibers having a diameter of about 90 nm which is relatively higher compared to the initial diameter of pure TOCN (~9 nm). Despite the physical and chemical treatment of TOCN during polymerization, the micrometric length of the cellulosic nanomaterial was maintained. In addition, the incorporation of polyvinyl alcohol as an additive in the TOCN/PPy composite seems to enhance the flexibility of composite films (bent up to 180°) without losing the high electrical conductivity. Finally, because of the high conductivity and good mechanical properties of the TOCN/PPy composite films obtained in this work, they can be used as a promising material in applications of sensors, flexible electrodes, and other fields requiring electrically conductive flexible films.     

具有柔性侧链的脂肪磺酸型磺化聚砜质子交换膜的制备及性能研究

以氯丁酰氯(CBC)为小分子试剂,通过傅-克酰基化反应在双酚A型聚砜主链引入可交换氯,制备了氯乙酰基化聚砜(CBPS),然后以羟乙基磺酸钠(HES)为试剂,与氯甲基通过亲核取代反应制备了一种具备较长柔性侧链的一种侧链脂肪磺酸型磺化聚砜(PS-ES),采用红外光谱和核磁氢谱标表征了它们的化学结构,并采用溶液浇注的方法制备了相应的聚砜阳离子交换膜(PSCEM),探索了PSCEM性能和温度之间的关系。结果表明:随着温度的升高,侧链末端的磺酸基团运动能力增强,导致PSCEM的吸水率(WU)、吸水溶胀性(SW)和质子传导率(PC)增加,由于制备的PS-ES膜材具备很长的柔性侧链,使相应PSCEM的亲水基团远离疏水聚合物主链,吸收的水分子被限制在亲水区域,降低了亲水部分对疏水主链的影响,使PS-ES膜在高磺化度下仍具备一定的尺寸稳定性,其中磺酸键合量为1.50mmol/g的PS-ES-3膜在25℃和85℃的吸水率分别是27.6%和43.6%,但是相应的吸水溶胀性仅为25.5%和55.7%,其中PS-ES-3在85℃的质子传导率达到了0.149S/cm,与商业化Nafion115的性能非常接近,表现出很好的综合性能。     

Poly(vinyl alcohol)-perfluorinated sulfonic acid nanofiber mats prepared via electrospinning as catalyst

Well-formed poly (vinyl alcohol) (PVA)-perfluorinated sulfonic acid (PFSA) nanofiber mats were fabricated via electrospinning process. Homogenous PFSA-PVA solutions were prepared by mixing PFSA-N, N-dimethylacetamide (DMAc) solution with PVA aqueous solution at different weight ratio. Increasing the weight ratio of PFSA in solution greatly increased the viscosity of the solution and slightly decreased the conductivity, which increased the diameter of the resulting PVA-PFSA nanofiber. The operating parameters such as tip to collector distance (TCD) and flow rate have a limited effect on the morphology of nanofibers, but high flow rate can improve the productivity. Ethyl acetate synthesis catalyzed by PVA-PFSA nanofiber mats was investigated, the results showed that all nanofibers have significantly catalytic activity, but the catalytic efficiency is related to the specific surface of PVA-PFSA nanofibers.