石墨纸-BaTiO_3/PI一体化复合薄膜的制备及研究

聚合物复合薄膜超级电容器因其可实现大面积制备、性能可靠等优点,引起了能源领域的广泛关注。如何实现导电层与介电层的一体化加工制备,是叠片式薄膜超级电容器的重要研究方向。本文介绍了以溶液混合法制备的钛酸钡/聚酰亚胺复合薄膜作为介电材料,以石墨纸作为电极材料以及复合薄膜的载体,利用提拉法制备石墨纸-钛酸钡/聚酰亚胺一体化复合薄膜,实现导电层与介电层直接成型的一体化制备过程。利用红外(FT-IR)、扫描电镜(SEM)、EIS和LCR电桥仪对复合薄膜进行表征分析。实验结果表明聚酰亚胺亚胺化完全,钛酸钡在复合薄膜中分散良好,复合薄膜的介电损耗非常小,很好地满足了高介电材料的应用要求。     

钛酸钡/碳化钛/聚酰亚胺三元复合薄膜的制备及性能研究

随着微电子工业的不断发展,高介电常数材料的发展已成为制约电子器件微型化、高速化的关键因素之一。本文以钛酸钡核碳化钛为填料,经硅烷偶联剂改性后按一定比例添加到聚酰亚胺中,制备出钛酸钡/碳化钛/聚酰亚胺(BaTiO3/TiC/PI)三元复合薄膜。对复合薄膜的显微结构及性能进行了分析。实验结果表明,无机填料在复合薄膜中具有较好的分散性,说明硅烷偶联剂改性后无机粉体与聚酰亚胺基体的相容性增加。性能测试表明,随着无机填料含量的增加,三元复合薄膜的拉伸强度和断裂伸长率均下降,而导电性能则逐渐提高。     

聚酰亚胺/钛酸钡复合薄膜的制备及性能

将钛酸钡(BT)粒子与聚酰胺酸溶液共混,亚胺化后得到聚酰亚胺(PI)包覆的BT(PI@BT)粒子.分别以BT粒子和PI@BT粒子为改性填料,通过原位聚合法制备了PI/BT和PI/PI@BT复合薄膜,对比了两种复合薄膜的结构与性能.结果表明:PI@BT粒子具有明显的核壳结构,较BT在PI基体中分散更均匀,从而有效地提高了...     

聚酰亚胺/聚苯胺/炭黑抗静电复合薄膜的制备与表征

采用原位复合的方法制备抗静电聚酰亚胺(PI)复合薄膜,以导电炭黑（CB）和聚苯胺（PANI）作为导电改性剂,研究了不同配比下CB与PANI对复合薄膜电性能的影响,通过扫描电子显微镜观察其形貌,同时对材料的热稳定性和力学性能进行分析。结果表明,混合填料填充的复合薄膜粒子间的分散性优于单独加入CB或PANI体系;当PANI和CB比为1∶2时表面电阻达到抗静电的要求且热稳定性最好。     

钛酸钡/氮化硼/聚酰亚胺三元复合薄膜的制备及其性能研究

采用超声剥离得到少层氮化硼,并以钛酸钡(BaTiO_3)和少层氮化硼为填料,按照一定的比例添加到聚酰胺酸(PAA)中,采用流延法经热亚酰胺后制备出高储能密度的钛酸钡/氮化硼/聚酰亚胺(BaTiO_3/BNNS/PI)三元复合薄膜。对复合薄膜的显微结构及性能进行了分析。结果表明,无机填料在复合薄膜中具有较好的分散性,并且在BNNS的添加量为12%,BaTiO_3的填充量为15%时,纳米薄膜的储能密度比纯PI提高了近4倍,同时复合薄膜的力学性能也得到了改善。     

有机硅改性聚酰亚胺复合膜的抗原子氧性能研究

由端氨丙基聚二甲基硅氧烷（PDMS）、均苯四甲酸二酐（PMDA）和4,4’-二氨基二苯醚（ODA）在N,N’-二甲基乙酰胺（DMAc）中共聚,热亚胺化法制备有机硅改性聚酰亚胺复合膜。通过傅立叶变换红外吸收光谱仪（FTIR）、X射线光电子能谱（XPS）分析材料的化学结构,采用扫描电子显微镜（SEM）观察材料的表观形貌,利用地面原子氧（AO）模拟设备研究了该复合膜的抗原子氧性能。结果表明有机硅改性聚酰亚胺复合膜在AO累积通量达到2.06?020atom/cm2时,复合膜的AO剥蚀率可以达到6.69?0-25 cm3/atom,约是纯聚酰亚胺薄膜抗原子氧性能的4.5倍。     

浸渍提拉法制备钛酸钡/聚酰亚胺复合薄膜及其低频介电性能研究

采用分层提拉法成功的制备了具有"三明治"结构的钛酸钡(BT)/聚酰亚胺(PI)复合薄膜。低频介电性能分析表明,本方法中PAA的最佳固含量为11%。0.1Hz下,复合薄膜的电容值达到49.5n F,是纯PI的146倍,而介电损耗为0.132,仅为纯PI的1.8倍。容量损耗增加比达到81.1。     

添加剂改性玉米醇溶蛋白复合膜的制备与表征

采用流延法制备高含量玉米醇溶蛋白（Zein）的Zein/壳聚糖（CS）复合膜，通过复合添加剂〔m(甘油)：m(聚乙二醇400)=1:1〕对Zein/CS复合膜共混改性，研究复合添加剂添加量（以总溶液质量计，分别为0、0.5%、1.0%、1.5%、2.0%）对薄膜的力学、光学和热学性能等的影响，并通过SEM、FTIR对薄膜形貌和结构变化进行表征。结果表明，复合添加剂通过削弱Zein和CS之间的分子间作用力，达到增塑效果，薄膜综合机械性能有所改善，随着复合添加剂添加量的升高，薄膜断裂伸长率逐渐增强，拉伸强度呈下降再上升的趋势；水蒸气透过率逐渐增加，水接触角逐渐减小，薄膜亲水性随之增强。与不含复合添加剂的薄膜（ZC-0）相比，当复合添加剂添加量为1.5%时，复合膜（ZC-1.5）的抗拉强度降低了27.40%，断裂伸长率增长了39.87%，水蒸气透过率上升了29.10%。通过SEM和DSC观察，添加复合添加剂改性后，改善了Zein和CS之间的相容性，制备的薄膜表面更加平整光滑。综合性能可得，制备高含量Zein的Zein/CS复合膜，复合添加剂浓度为1.5%时，薄膜性能最优。并在含有1.5%复合添加剂的Zein/CS薄膜中添加了一定量的姜黄素，据测定其能够有效提高薄膜的抗氧化性能至55.18%。     

碳化钛/聚酰亚胺高介电复合薄膜的制备及性能研究

采用机械共混法将经硅烷偶联剂改性的碳化钛粉体掺杂入聚酰亚胺中,制备了碳化钛/聚酰亚胺复合薄膜。分析了不同碳化钛粒子含量对复合薄膜的显微结构、力学性能及介电性能的影响。实验结果表明,随着纳米TiC含量的不断升高,复合薄膜的拉伸强度呈现先上升后下降的趋势,复合薄膜的耐电击穿场强迅速下降。与此同时,复合材料的介电常数则显著提高。     

制备高反射高导电的聚酰亚胺银膜的新方法——原位一步法制备技术

采用原位一步法,通过选用不同原材料和制膜工艺,制备了高反射、高导电的聚酰亚胺/银复合膜,该薄膜兼具有银的高反射率和高导电性以及聚酰亚胺的高强度和耐高低温性.银以纳米粒子形式镶嵌于聚酰亚胺表面,使银层与聚酰亚胺基体之间形成强烈的互锁结构,从而不易脱落,该薄膜可用于反射和导电涂层.     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.