聚酰亚胺泡沫塑料制备与性能研究

采用一步缩聚法制备了聚酰亚胺(PI)泡沫塑料,并对其结构和性能进行了表征。经红外光谱测定,在1778、1720cm-1和1375cm-1处观察到PI特征峰。实验结果表明,所得PI泡沫塑料孔径均匀,平均密度小于0.30g/cm3,极限氧指数为38%,平均吸声系数为0.42,玻璃化转变温度为262.4℃,起始分解温度为549.7℃。     

酯化法合成聚酰亚胺泡沫塑料的研究

以3,3',4,4'-二苯酮四酸二酐、3,3',4,4'-二苯醚四酸二酐、4,4'一二胺基二苯甲烷、4,4'-二胺基二苯醚和4,4'-二胺基二苯砜为单体,甲醇和四氢呋喃混合溶剂,采用酯化法制备了5种聚酰亚胺(PI)泡沫塑料.红外光谱分析证实,由二酐的二酸二酯和二胺反应生成了聚酯铵盐前驱体(PEAS),且通过微波辐照发泡方法由PEAS粉末成功制得了PJ泡沫塑料.结果表明,5种PI泡沫塑料平均密度为11 kg/m<'3>,阻燃性能和耐高温性能优异,四元共聚型的P14和P15泡沫塑料压缩永久形变最小、耐高温性能最佳.     

聚酰亚胺泡沫塑料开发研究概述

介绍了聚酰亚胺泡沫塑料的6种合成方法和制备工艺中所应注意的几个方面(发泡方法、泡孔大小和形状控制等)。并综述了聚酰亚胺泡沫塑料的高低温性、高抗拉强度、高弹性模量、耐辐射性、高介电性能等优异的性能及其在透波材料、阻尼材料、耐高温材料、低放气材料、低温材料、复合材料、介电材料等方面的应用。聚酰亚胺泡沫塑料的发展还应有更广阔的空间。     

聚酰亚胺泡沫塑料的合成路线及制备工艺

综述了主链聚酰亚胺泡沫塑料的各种合成路线和制备工艺中的发泡剂、发泡方法及泡孔结构的控制方法,分析对比了不同合成路线和制备工艺的技术特点;并介绍了侧链型聚酰亚胺泡沫塑料以及聚酰亚胺纳米泡沫塑料的合成路线和制备工艺。聚酰亚胺纳米泡沫塑料的纳米效应及其物理化学性能研究等也将是今后的重点。     

聚酯铵盐粉末发泡制备聚酰亚胺泡沫材料的研究

以芳香二酐和二胺为单体,采用聚酯铵盐前体粉末发泡的方法制备聚酰亚胺泡沫材料。考察了发泡温度、粉末大小对泡孔结构的影响。力学和热性能测试结果表明,该泡沫材料拉伸行为呈脆性,而压缩行为呈塑性,密度较大的聚酰亚胺泡沫表现出较好的力学性能。随着泡沫材料密度增大或测试温度升高,聚酰亚胺泡沫的导热系数增大。     

喷雾干燥法制备粉末橡胶及其硫化性能研究

以超声分散的炭黑悬浮液填充天然胶乳,采用喷雾干燥法制备粒径小于5μm的粉末橡胶。结果表明,对于固形物质量分数约为0.1的炭黑/天然胶乳悬浮液,当喷雾干燥机的浆料进口温度约180℃、进给量约15%、吸气量为100%时,粉末橡胶制备过程较为顺利且制得的粉末橡胶颗粒细小、尺寸均匀;在相同的硫化条件下,与机械混炼法相比,喷雾干燥法制得的粉末橡胶硫化性能显著改善,硫化曲线的转矩峰值提高约1倍;粉末橡胶对氧化锌、硬脂酸、硫黄、促进剂CZ和DM的需求量更大,当以上小料用量均提高至普通机械混炼胶料2倍时,粉末橡胶硫化曲线的转矩峰值大幅度提高,由约30 N.m提高至约60 N.m,比普通机械混炼胶料提高约3倍。     

冰浴法制备浅色透明聚酰亚胺薄膜

采用冰浴法,以二胺单体1,4-苯二甲胺(P-XDA)与二酐单体4,4'-氧双邻苯二甲酸酐(ODPA)、3,3',4,4'-二苯甲酮四甲酸二酐(BTDA)合成了两种聚酰亚胺(PI)薄膜.在二元聚合的基础上,引入脂环二胺4,4'-二氨基二环己基甲烷(PACM)进行三元聚合得到两种PI薄膜.通过红外光谱、紫外可见光谱、热机械...     

水分散法制备EVA粉末

本文论述了以烷基苯磺酸钠代替国外Pluconics F-108表面活性剂,在水分散体系中制备乙烯-醋酸乙烯共聚物(EVA)粉末的方法。结果表明:EVA颗粒在水分散体系中以无机碱类和无机盐类作为助分散剂,使用国产普通烷基苯磺酸钠,在高速搅拌状态下,可以制得粒度分布范围较窄,粒径在40～200目的球状粉末。该粉末与深冷法加工的粉末相比,具有外形呈球状,粒度均匀的特点,因此更适合于热熔粘合衬芯布的加工上。     

爆炸法生产网化聚氨酯泡沫塑料

以聚醚多元醇、聚合物多元醇、甲苯二异氰酸酯及多种添加剂为原料，采用水发泡，制成块状软质聚氨酯泡沫塑料；将其放入网化箱中，充入氢气与氧气，混合均匀后，引爆，制得网状泡沫塑料，介绍了块泡生产的基本配方，爆炸法网化工艺过程，对氢气与氧气的用量及混合时间进行了讨论，并介绍了网化泡沫的物理性能。     

Preparation of polyimide powder

A polyimide powder was prepared from 3,3′,4,4′-biphenyl tetracarboxylic dianhydride (BPDA) and 4,4′-oxydianiline (ODA). Polyimide powder having low molecular weight was prepared by imidizing low-molecular-weight polyamic acid. The molecular weight of this polyimide powder increased on heating in a solid state. The molecular weight increased with the decrease of crystallinity of polyimide. © 1996 John Wiley & Sons, Inc.     

Visualization study of foaming process for polyimide foams and its reinforced foams

In this article, the foaming processes of polyimide foams and its reinforced foams were observed by a self‐made visualization device at different heating rates ranging from 10°C/min to 120°C/min. Contributing factors such as chemical structure of polyimide, fillers, and heating rate were investigated to determine the effects on the inflation onset temperature and morphological change of polyimide foam precursor powders. The results showed that the powder might grow into a single bubble mesostructure at a lower heating rate or a multibubble mesostructure at a higher heating rate. Because of the filling of reinforcing fillers, the inflation morphology of reinforced polyimide foam precursor powders show a different change trend with the increase of temperature compared to the pure polyimide foam precursor powders. For all kinds of polyimide foam precursor powders investigated in this article, the inflation morphologies showed a similar variation trend with different heating rates, and the final inflation degrees were slightly different. The inflation onset temperatures of all polyimide foam precursor powders studied decreased with increasing heating rate. POLYM. COMPOS., 2010. © 2008 Society of Plastics Engineers     

高发泡倍率聚丙烯泡沫材料的研制

研究了高熔体强度聚丙烯（HMSPP）／共聚聚丙烯（PP）／低密度聚乙烯共混体系的发泡性能。通过考察不同组分及含量、共混体系的熔体流动速率、熔体强度、储能模量和损耗模量研究体系结构性能间的差异。当m（HMSPP）／m（PP））为7：93时．发泡制品的密度约为0．12g／cm^3,所得制品泡iL尺寸均匀、泡壁薄、外观规整。研究发现．当化学发泡剂含量为2-3质量份、成核剂含量为O．1～0．2质量份时,得到的制品密度较低、泡孔结构规整。     

Preparation and characterization of high‐temperature resistance polyimide foams

A new high‐temperature resistance polyimide foam was synthesized from 2,3,3′,4′‐biphenyltetracarboxylic dianhydride (α‐BPDA) and p‐phenylenediamine (p‐PDA). The structures and foaming process of polyimide precursor powders were characterized by wide‐angle X‐ray diffractometer (WXRD) and the self‐made visualization device, respectively. The imidization degree, thermal mechanical properties and thermal stability of the polyimide foams with different post‐treatment temperatures were also measured by fourier transform infrared spectrometer spectrum (FTIR), dynamic thermal mechanical anaylsis (DMTA), and thermogravimetric analysis (TGA). Results showed that the inflation onset temperatures of polyimide precursor powders ranged from 122 to 135°C with varying the heating rate. And the increase in the imidization degree, glass transition temperatures (T_g) and temperatures for 5 wt% mass loss of high‐temperature resistance polyimide foams can be achieved with increasing post‐treatment temperature. It was quite surprising to find that T_g of high‐temperature resistance polyimide foam post‐treated at 420°C was up to above 450°C, and the char yield at 800°C was more than 60%. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Preparation and properties of rigid polyimide foams derived from dianhydride and isocyanate

A series of rigid polyimide (PI) foams were synthesized via the reaction of a first solution with a second solution. The first solution was isocyanate‐terminated polyimide prepolymers; the second solution contained deionized water and surfactant. The effect of different water contents and isocyanate index on the structures and properties of rigid PI foams were investigated. The apparent density, hardness, compressive strength, and the 5% weight loss temperatures (T_5%) decreased with the increase of water content. With the increase of isocyanate index, the apparent density and the T_5% values decreased, whereas the glass transition temperatures (T_g) increased and the hardness, compressive strength first increased and then decreased. The rigid PI foams composed of closed‐cells were confirmed by scanning electron microscopy. The maximum compressive strength of rigid PI foams prepared was up to 1.31 MPa. Moreover, excellent thermal stability was presented with the T_5% values were all above 360°C and the residual weights of the foams (R_w) were more than 50% at 800°C. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

开孔聚酰亚胺泡沫粘接性能研究

探讨了BHPI-J-2010胶粘剂的固化度、耐热性、固化工艺、粘接铝的拉剪强度及粘接聚酰亚胺泡沫的可行性;研究了BHPI—J-2010胶粘剂粘接聚酰亚胺泡沫／45号钢的拉伸性能及固化工艺;考查了开孔聚酰亚胺泡沫／45号钢粘接试样高温拉伸和蠕变性能及胶粘剂的使用寿命。结果表明,BHPI—J-2010胶粘剂对开孔聚酰亚胺泡沫具有良好的粘接性能。     

镍包石墨粉聚酰亚胺导电胶的制备与性能表征

先将石墨粉预处理,后采用化学镀法与配制的镀液制备镍包石墨粉,最后加入聚酰亚胺树脂超声制备镍包石墨粉聚酰亚胺导电胶。对合成的镍包石墨粉进行SEM(扫描电镜)表征,探讨超声时间对剪切强度的影响、使用温度和填料含量对体积电阻率的影响、固化温度对电导率的影响以及导电胶在镀铜基板和镀锌基板上接触电阻的比较。研究结果表明:化学镀温度为80℃时,镍包石墨粉包覆效果良好;超声时间15 min、固化温度170℃、填料含量8%制备的导电胶性能较佳,且导电胶使用温度不宜超过200℃;导电胶在镀铜基板上的老化表现优于镀锌基板。制备的镍包石墨粉聚酰亚胺导电胶基本达到了作为导电胶的使用需求,进一步研究应用具有一定的市场前景。     

Preparation and properties of polyimide/silver foams using a direct ion exchange method

A novel polyimide/silver (PI/Ag) foam was prepared by isocyanate foaming and direct ion exchange between Ag⁺ ions from silver nitrate and the H⁺ ions in the carboxyl (–COOH) groups of the polyamide molecular chain. The microstructures, chemical and phase composition of the PI/Ag foams were tested by SEM, FT-IR and XRD. The properties were tested by TG, DSC and UV spectrophotometer. The effects of different Ag contents on the microstructures and properties were analysized. SEM results showed that the PI/Ag foams had present the opened-cells type. With the increase in the Ag⁺ ions contents, both the amount of silver particles and the UV reflectivity of the PI/Ag foams increased, as the size of silver particles decreased. FT-IR test results show that the introduction of the silver nano-particles have no significant effect on the chemical structure of the PI foams. XRD results indicate that the silver nano-particles are face-centered cubic structure and have good crystalline properties. Thermal tests results show that the PI/Ag foams maintain the excellent thermal stability. Based on the above experimental results, the reaction mechanism during the foaming and curing process were also analysized.     

Preparation of 6FDA-based polyimide composite membrane by CVDP process

Preparation of polyimide composite membranes by a chemical vapor deposition and polymerization process (CVDP) was studied for the development of pervaporation or gas separation membranes. Hexafluoroisopropylidene-2,2-bis [phethalic acid anhydride] (6F-dianhydride) (6FDA) and 4,4′-diaminodiphenyl ether (ODA) were used as monomers and were simultaneously deposited on an asymmetric polyimide membrane in vacuum of 10⁻⁶ Torr. The deposited layer of the monomers was converted to polyimide by heating at 250°C at 3 h in an ordinary vacuum oven, and its separation performance for water-ethanol and CO₂−N₂ systems was characterized.