电子入射角度对聚酰亚胺二次电子发射系数的影响

采用具有负偏压收集极的二次电子发射系数测试系统, 对聚酰亚胺样品的二次电子发射系数与入射电子角度和入射电子能量的关系进行了测量. 测量结果表明, 在电子小角度入射样品的情况下, 随着入射角度的增加, 二次电子发射系数单调增加, 并符合传统的规律, 但是在电子大角度入射时, 却与此不符合. 测量显示, 出现偏差时对应的临界电子入射角度随着入射电子能量的降低而减小. 采用简化的电子弹性散射过程和卢瑟福弹性散射截面公式对这种偏差的出现进行了分析, 并推导出修正后的二次电子发射系数的计算公式. 修正后的二次电子发射系数的计算结果更加符合实验结果.     

用于质子交换膜的磺化聚酰亚胺的合成与性能研究

从分子设计的角度出发, 合成了一种新型的磺化二胺单体, 通过聚合反应制备了磺酸基在侧链上的质子交换膜. 由于特殊结构的设计, 这种质子交换膜的水解稳定性和氧化稳定性均得到提高.     

3,3'-二氨基查尔酮的合成

3;3'-二氨基查尔酮的合成;光敏性二胺;查尔酮;聚酰亚胺;合成     

溶剂对聚酰亚胺电化学行为的影响

运用电化学循环伏安等方法研究了有机溶剂对可溶性聚酰亚胺(PI)电化学行为的影响.结果表明,PI在一些溶剂中能进行电化学反应.红外光谱研究表明溶剂对PI电化学行为的影响主要取决于不同结构的溶剂与PI之间的相互作用.     

溶胶-凝胶法制备聚酰亚胺/二氧化钛感光杂化材料

高聚物 -无机物纳米杂化材料的研究已成为当今高分子化学和物理、无机化学和材料化学等许多学科交叉的前沿领域 [1] .聚酰亚胺因其特有的优越性能而成为聚合物中的热选材料 ;感光聚酰亚胺除具备常规聚酰亚胺的优良性能 ,还由于可在材料上直接刻蚀图形 ,简化工艺步骤 [2 ] ,作为通信产业中光波导、光联接等装置的材料而受到市场的关注 .目前有很多关于无机材料 Ti O2 和 Si O2 用于电光领域材料[3～ 5] 及其与聚合物形成的杂化材料用于制作光波导、光联结等电光领域的文献 [6,7] 报道 ,但很少见到可直接刻蚀图形的无机 /聚酰亚胺杂化材料 […     

光敏性聚酰亚胺的合成及其在液晶光致取向中的运用

通过羟基聚酰亚胺与肉桂酸的接枝反应合成了具有光敏性的聚酰亚胺,并且通过红外,核磁确定了光敏性聚酰亚胺的结构,将合成的聚酰亚胺作为液晶取向层用在液晶显示器件中,证明其有良好的热稳定性。     

Synthesis and characterization of soluble fluorine‐containing polyimides based on 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene

The synthesis and properties of a class of soluble fluorine‐containing aromatic polyimides are described. Substituents of trifluoromethyl groups on the aromatic rings of paralinked aromatic ether diamine conferred the polymer prepared thereof with enhanced solubility, low‐moisture absorption, and low dielectric constants. The polyimides also exhibited exceptional thermal stability, good mechanical properties, and excellent hygrothermal resistance. These outstanding combined features ensure the polymers are desirable candidate materials for advanced microelectronics applications. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2581–2590, 2001     

Preparation and properties of polybenzoxazine/poly(imide‐siloxane) alloys: In situ ring‐opening polymerization of benzoxazine in the presence of soluble poly(imide‐siloxane)s

Benzoxazine monomer (Ba) was blended with soluble poly(imide‐siloxane)s in various weight ratios. The soluble poly(imide‐siloxane)s with and without pendent phenolic groups were prepared from the reaction of 2,2′‐bis(3,4‐dicarboxylphenyl)hexafluoropropane dianhydride with α,ω‐bis(aminopropyl)dimethylsiloxane oligomer (PDMS; molecular weight = 5000) and 3,3′‐dihydroxybenzidine (with OH group) or 4,4′‐diaminodiphenyl ether (without OH group). The onset and maximum of the exotherm due to the ring‐opening polymerization for the pristine Ba appeared on differential scanning calorimetry curves around 200 and 240 °C, respectively. In the presence of poly(imide‐siloxane)s, the exothermic temperatures were lowered: the onset to 130–140 °C and the maximum to 210–220 °C. The exotherm due to the benzoxazine polymerization disappeared after curing at 240 °C for 1 h. Viscoelastic measurements of the cured blends containing poly(imide‐siloxane) with OH functionality showed two glass‐transition temperatures (T_g's), at a low temperature around ?55 °C and at a high temperature around 250–300 °C, displaying phase separation between PDMS and the combined phase consisting of polyimide and polybenzoxazine (PBa) components due to the formation of AB‐crosslinked polymer. For the blends containing poly(imide‐siloxane) without OH functionalities, however, in addition to the T_g due to PDMS, two T_g's were observed in high‐temperature ranges, 230–260 and 300–350 °C, indicating further phase separation between the polyimide and PBa components due to the formation of semi‐interpenetrating networks. In both cases, T_g increased with increasing poly(imide‐siloxane) content. Tensile measurements showed that the toughness of PBa was enhanced by the addition of poly(imide‐siloxane). Thermogravimetric analysis showed that the thermal stability of PBa also was enhanced by the addition of poly(imide‐siloxane). © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2633–2641, 2001     

含有p-n单元的苝聚酰亚胺的合成及其敏化光电池的性能研究

设计、合成并表征了含有p-n(供电子-吸电子)单元的苝聚酰亚胺PPI, 并研究了其作为敏化电极材料的光电池的性能. 产物为非晶态. 从电子谱中计算出其能带带宽为2.16 eV, 用电化学循安伏安法计算得到其电子亲和势(E_a, 最低空轨道能级)为－3.97 eV, 离子势(IP, 最高占据轨道能级的绝对值)为6.13 eV, 其能级与二氧化钛的能级相匹配, 对二氧化钛有较好的敏化作用. 光电池的光电流作用谱(IPCE)与紫外电子谱十分相似, 光电压与光强之间有指数的关系. 用苝聚酰亚胺为敏化剂的光电池的光电转换效率为0.0135%.     

A rod‐like fluorinated polyimide as an in‐plane birefringent optical material 2: Control of optical retardation using spontaneous molecular orientation

Following previous work, a fluorinated polyimide with a rod‐like structure has been investigated as an in‐plane birefringent optical material whose birefringence and thickness can be precisely controlled. Poly(amic acid) films fixed in a metal frame by two sides and thermally cured without any drawing resulted in a polyimide film with an in‐plane birefringence (Δn) larger than 0.1 at 1543 nm. The optical retardation, which is defined as the product of Δn and the film thickness, was controlled by varying the curing and post‐annealing temperatures and by using reactive ion etching. In situ measurements of the tensile stress and the generated retardation showed that the initial orientation at below 200°C was due to the large tensile stress caused by the film shrinkage during imidization and that the increased Δn at higher temperatures was caused by the spontaneous orientation of the polyimide molecules. The curing temperature dependence of refractive indices, optical transmittance in the visible and near‐infrared region, and the wavelength dispersion of retardation of the in‐plane birefringent polyimide films are also reported. Copyright © 1999 John Wiley & Sons, Ltd.