柔性OLED显示用聚酰亚胺基板的合成与性能

合成了一种含吡啶结构的刚性二胺,2-(4-氨基苯基)-5-氨基吡啶(PD),将其与二氨基二苯醚(ODA)以及均苯四甲酸二酐(PMDA)共聚,调控分子链中刚性与柔性结构单元的比例,制备出一系列聚酰亚胺共聚物.结果表明:随着聚酰亚胺中含吡啶结构的刚性二胺PD含量增加,玻璃化转变温度显著提高(Tg>450℃),热膨胀系数逐渐降低(CTE<5×10^-6K^-1,50～400℃).同时,聚酰亚胺薄膜的拉伸强度提高(1.25倍),模量显著增加(4.53倍),但仍保持较高的断裂伸长率(>35%).利用广角X射线衍射(WAXD)分析聚合物聚集态结构表明,含吡啶结构刚性二胺(PD)的引入使聚酰亚胺分子链倾向于有序排列和紧密堆积,结晶度增加.因此,通过调控聚合物链中刚性二胺(PD)含量可使PI薄膜同时达到优异的尺寸稳定性、高耐热性、高强度以及较好的柔韧性,此类PI有望应用于柔性OLED显示领域.     

含三氟甲基聚酰亚胺的合成与性能研究

通过在4,4′-二氨基二苯醚(4,4-′ODA)单体中引入三氟甲基合成了一种新型二胺单体2-三氟甲基-4,4′-二氨基二苯醚(3FODA),该单体具有良好的溶解性和高的反应活性,使用3FODA替代4,4′-二氨基二苯甲烷(MDA)制备了PMR热固性聚酰亚胺树脂.树脂溶液高浓度低粘度,具有室温下良好的储存稳定性;树脂具有很好的加工性能,成型后的模压件显示了优异的热性能和耐热氧化稳定性,玻璃化转变温度在336~379℃之间;此外树脂具有较好的电性能和较低的吸水率.     

柔性热电器件的制备与性能研究

介绍了有机/无机复合热电材料的柔性器件, 按照柔性器件的组装制备方式, 以串联型、 堆砌型和折叠型3种类型, 详细地总结了其制备过程与器件热电性能, 探讨该领域的研究进展, 并对其发展前景进行展望.     

柔性交联型聚酰亚胺气凝胶的制备及性能

利用溶胶-凝胶反应制备了聚酰亚胺凝胶, 经过超临界干燥得到了聚酰亚胺气凝胶. 研究了固含量和交联剂比例对气凝胶性能的影响规律. 结果表明, 聚酰亚胺气凝胶的密度和线收缩率都随着固含量和交联剂比例的增加而增加; 随着固含量的增加, 气凝胶的室温热导率呈现出先降低再增加的趋势(0.026~0.033 W·m^-1·K^-1), 气凝胶的力学刚度和强度明显提升; 交联剂的加入, 可以提高材料的韧性, 断裂应变最高达21.7%; 制得的柔性聚酰亚胺气凝胶具有良好的热稳定性, 是满足尖端武器以及空间飞行器对于轻质、 柔性热防护要求的理想材料之一.     

轻质柔性聚酰亚胺纸基电磁屏蔽材料的制备与性能

基于聚酰亚胺纤维纸基导电骨架(PI-CP)的三维网络结构, 通过聚吡咯(PPy)的气相沉积及无钯化学镀工艺在PI-CP上进行镍基金属的层层组装, 制备了夹芯结构的镍/聚吡咯@聚酰亚胺纤维纸基电磁屏蔽材料 (Ni/PPy@PI-CP); 对其形貌、 结构、 导电性能、 力学性能及电磁屏蔽性能进行了表征; 并考察了温度、 弯曲牢度和折叠次数对Ni/PPy@PI-CP导电性能和电磁屏蔽性能的影响. 研究结果表明, Ni/PPy@PI-CP-3的电磁屏蔽性能可达到70 dB以上; Ni/PPy@PI-CP-3在弯曲变形下表现出优良的导电稳定性, 其电导率损失可以忽略不计, 经过200次的反复弯曲测试, 其电导率仍保持在92.4%以上. 此外, Ni/PPy@PI-CP还具有轻质及易于加工的特性, 并具有稳定的热性能, 于300 ℃下处理后电磁屏蔽性能仍保持在80％以上.     

双酚F型聚酰亚胺薄膜的制备与性能

以4-氯代酞酰亚胺和双酚F为原料,在N,N′-二甲基乙酰胺溶剂中,经水解、酸化、脱水,合成了一种新型的双酚F型二酐(BPFDA)单体,并用1H NMR和IR测试方法确认了其结构。 采用传统的一步法,用N,N′-二甲基乙酰胺作溶剂,BPFDA分别与4,4′-二氨基二苯醚（ODA）和4,4′-二氨基二苯甲烷（MDA）聚合,得到聚酰胺酸,并进一步热亚胺化得到聚酰亚胺薄膜,并对其进行了表征。 结果表明,BPFDA/ODA薄膜和BPFDA/MDA薄膜的玻璃化转变温度分别为200和204 ℃; 热失重分析表明,质量损失5%的温度分别为506.50和459.10 ℃;其拉伸强度分别为110和100 MPa。     

柔性TiO2纳米管薄膜电极的制备及其光电性能

采用水热合成法制备出TiO₂纳米管,通过XRD、TEM和氮气等温吸附-脱附仪等测试手段对TiO₂纳米管进行了表征.用烧结的TiO₂纳米管和P25粉末混合制成薄膜电极,并研究了薄膜电极的表面形貌、染料吸附量和光电性能.研究表明,加入TiO₂纳米管可以制备出机械稳定的薄膜;掺杂TiO₂纳米管的含量越多,薄膜电极的染料吸附量越大;掺杂5%烧结纳米管粉末的薄膜电极的光电性能最好,其短路电流可达3.25mA,光电转换效率达到1.67%.     

MgF2改性Alq3纳米复合材料的制备及其对OLED抗老化性能的提高

提高有机电致发光器件(OLED)的稳定性和寿命是其市场化应用中需要解决的关键问题.本文从提高发光材料自身的稳定性出发,以Mg(CF₃COO)_2-x(CH₃COO)_x溶胶为前驱体,将其与8-羟基喹啉铝(Alq₃)混合浓缩成糊状后, 300 ℃真空烧结,经过MgF₂的生成和Alq₃的相变后,形成了一系列Mg含量不同的具有超结构ε相的纳米复合材料Alq₃-MgF₂.研究结果表明,相比于纯Alq₃, Alq₃-MgF₂纳米复合材料制备的OLED可以很好地保持Alq₃的发光特性,同时,其抗老化性能得到显著提高.特别是, Mg(CH₃COO)₂投料量为Alq₃的5% (摩尔分数)时,所得Alq₃-MgF₂纳米复合材料制备的器件抗老化性能最优,在空气中老化72 h,最大发光亮度仍保持在起始值的93.5%;而Alq₃制备的OLED在空气中老化24 h后基本失活.     

高取代度玉米醋酸酯淀粉的制备与表征

高取代度玉米醋酸酯淀粉的制备与表征;取代度;醋酸酯淀粉;玻璃化转变温度;结晶度     

Effect of alumina concentration on thermal and structural properties of mas glass and glass-ceramics

Magnesium aluminum silicate (MAS) glass samples with different concentrations of alumina (7.58 to 14.71 mol%) were prepared by melt and quench-technique. Total Mg content in the form of MgF₂+MgO was kept constant at 25 mol%. MAS glass was converted into glass-ceramics by controlled heat treatment at around 950°C. Crystalline phases present in different samples were identified by powder X-ray diffraction technique. Dilatometry technique was used to measure the thermal expansion coefficient and glass transition temperature. Scanning electron microscopy (SEM) was employed to study the microstructure of the glass-ceramic sample. It is seen from X-ray diffraction studies that at low Al₂O₃ concentrations (up to 10.5 mol%) both MgSiO₃ and fluorophlogopite phases are present and at higher Al₂O₃ concentrations of 12.3 and 14.7 mol%, fluorophlogopite and magnesium silicate (Mg₂SiO₄), respectively are found as major crystalline phases. The average thermal expansion co-efficient (_avg) of the glass samples decreases systematically from 9.8 to 5.5·10^–6 °C^–1 and the glass transition temperature (T g) increases from 610.1 to 675°C with increase in alumina content. However, in glass-ceramic samples the _avg varies in somewhat complex manner from 6.8 to 7.9·10^–6 °C^–1 with variation of Al₂O₃ content. This was thought to be due to the presence of different crystalline phases, their relative concentration and microstructure.Authors wish to thank Dr V. C. Sahni, Director Physics Group and Dr J. V. Yakhmi, Head TPPED, BARC for encouragement and support to the work. They would like to thank Dr S. K. Kulshreshtha for many useful discussions. Technical assistance from Shri B. B. Sawant, Mrs Shobha Manikandan, Mr Rakesh Kumar and Shri P. A. Wagh is gratefully acknowledged. One of authors (BIS) would like to thank BRNS-DAE for awarding him KSKRA fellowship.     

Thermal coefficient of linear expansion of non-crystalline chalcogenides in the As-S-Se-Te-I system

The object of the paper is an investigation of the glasses of the (As₂S₃)_x(AsSe_0.5Te_0.5I)_100-x. type for 65≤;x≤;95, using methods of thermomechanical analysis. Values of the thermal coefficients of linear expansion in solid and visco-plastic phase were determined. it was shown that introducing arsenic-sulfide in glass-matrix AsChI, i.e. (AsSe_0.5Te_0.5I), leads to an increasing stability of these glasses. The characteristic temperatures of softening Tg and the temperature of the beginning of deformation t_w increase by increasing content of As₂S₃. The analytical forms of dependence of four significant physical values α_g, α_l, Tg, Tw, as a function of As₂S₃ content in the structure of glasses were fitted. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effect of Copper on Thermomechanical Characteristics of Amorphous AsSeyIz

The paper describes results of a study of glasses of the type Cu_x (AsSe_1.4 I_0.2 )_100–x for x =0, l, 5, 10, 15, 20 and 25 at% Cu, by the methods of thermomechanical analysis. Values of the thermal coefficients of linear expansion in solid and visco-plastic phase were determined and the dependence of this parameter on copper concentration was established. The experimental method used enabled the determination of characteristics glass transition temperature and the temperature of the beginning of deformation, and it was found that these parameters increase with increase in the copper content. This revised version was published online in July 2006 with corrections to the Cover Date.     

Structural and compositional effects on thermal expansion behavior in polyimide substrates of varying thicknesses

Polyimide films with thicknesses ranging from 6 μm to 80 μm were prepared with a solvent casting method to explore film thickness effects on the in-plane thermal expansion coefficient (CTE). In the case of polyimide films composed of bulky and flexible molecular units, CTE is consistent regardless of film thickness. In contrast, films with rigid and planar molecular structure show CTE increase according to the increase of film thickness up to 40–50 μm, which then plateau for thicker films. It is apparent that the film thickness dependent thermal expansion originates from complex effects of molecular orientation, charge transfer complex formation, and crystal formation as a function of film thicknesses, through characterization on UV–Vis absorption, crystalline structure, glass transition behavior, and optical retardation. These results provide insight into the design of polymer structures for flexible display substrates that require appropriate CTE values.     

含氟聚酰亚胺1,3-BPA-6FDA-DR1的合成及其热光性能

用1,3-双(3-氨基苯氧基)苯(1,3-BPA)、4,4′-(六氟异丙基)-苯二酸酐(6FDA)和分散红1(DR1)合成了含氟聚酰亚胺,采用示差扫描量热(DSC)、热失重分析(TGA)和紫外、红外吸收光谱等测试技术对该聚酰亚胺的热稳定性和结构进行了表征。结果显示,该聚酰亚胺的玻璃化转变温度(Tg)和在5%的质量损失温度分别为238和287℃,表明具有较好的热稳定性。不同浓度的材料在自然光下的热光系数(dn/dT)值为(-2.31～-3.04)×10-4/℃,体积热膨胀系数变化率(dβ/dT)为(2.56～4.32)×10-7/℃;一定浓度的材料在436nm单波长光照射下的热光系数(dn/dT)值为-3.08×10-4/℃,体热膨胀系数变化率(dβ/dT)为4.72×10-7/℃,表明该聚合物在低驱动功率的新型数字热光开关、光通信器件等领域具有潜在的应用前景。     

低热膨胀聚酰亚胺薄膜的研究进展与展望

聚酰亚胺是一种很有发展前途的高分子材料,热膨胀系数高的问题限制了聚酰亚胺的应用,降低热膨胀系数已成为聚酰亚胺研究热点之一。本文概述了国内外关于降低聚酰亚胺薄膜热膨胀系数的主要方法:分子结构设计法、共聚法、树脂共混法、添加纳米粒子法。阐述了工艺因素(如涂膜方式、牵伸条件等)对聚酰亚胺热膨胀系数的影响,并对未来低热膨胀系数聚酰亚胺薄膜的发展方向进行了展望。     

Preparation and Properties of Imidazole-containing Polyimide/Silica Hybrid Films

Imidazole-containing polyimide/silica（PI/SiO2） hybrid films were prepared from 3,3＇,4,4＇-biphenyltetra- carboxylic dianhydride（BPDA） and 2,2＇-di（p-aminophenyl）-5,5＇-bibenzimidazole in N,N-dimethylacetamide（DMAc） by sol-gel method and thermal imidization. The hybrid film with high silica mass fraction up to 40% was transparent. Scanning electron microscope（SEM） and transmission electron microscope（TEM） results of the film indicate a ho- mogeneous dispersion of silica nanoparticles in the polyimide matrix. One hybrid film PI/SiO2 with 15% SiO2 exhi- bits better mechanical properties with a tensile strength of 222 MPa, an elongation at break of 12%, and a tensile modulus of 5.66 GPa. The reinforced mechanism on mechanical Drooerties was also studied.