系列聚酰亚胺的制备及其结构表征

以二苯醚四羧酸二酐（0DPA）为二酐单体,对苯二胺（PDA）和二胺基二苯基醚（ODA）为二胺单体,通过低温缩聚合成一系列聚酰胺酸（PAA）和聚酰亚胺（PI）薄膜,对其结构和力学性能进行表征,并比较ODPA—PDA和ODPA—ODA薄膜的力学性能。结果表明,PAA的酰亚胺化较完全;链节元素组成与空间构型对于PAA与PI薄膜的力学性能影响较大,其中,PI（ODPA—PDA）薄膜的拉伸强度达到450MPa。     

三元共聚聚酰亚胺纤维的制备

针对均苯四甲酸二酐和4,4′-二氨基二苯醚体系两步法制备的聚酰亚胺(PI)纤维强度比较偏低的问题,加入刚性单体对苯二胺,在N-甲基吡咯烷酮中进行三元共聚得到聚酰胺酸(PAA),选用水和乙醇的混合溶液为凝固浴通过干湿法纺制出PAA纤维。对PAA纤维进行不同倍数的拉伸,然后通过优化酰亚胺化条件制得了致密的PI纤维,处理温度在400℃时,其强度和模量可分别达到4．29 cN/dtex和389 cN/dtex。     

聚酰胺酸酰亚胺化条件及其对聚酰亚胺力学性能的影响

采用均苯四酸二酐(PMDA)和4,4'-二氨基二苯醚(ODA)为单体,N-甲基吡咯烷酮(NMP)为溶剂,合成了黏度为1.87 dL/g的聚酰胺酸(PAA)。对聚酰胺酸分别进行了热酰亚胺化和化学酰亚胺化处理,研究了完全酰亚胺化所需的条件以及不同酰亚胺化方式对聚酰亚胺(PI)纤维条断裂强度的影响;对PAA初生纤维条进行拉伸和酰亚胺化处理的顺序不同,所得到的聚酰亚胺(PI)纤维条的力学性能不同,采用先酰亚胺化再拉伸的方法能得到力学性能更优异的聚酰亚胺(PI)纤维条。     

聚酰胺酸纤维热酰亚胺化的研究

采用聚酰胺酸纤维热酰亚胺化处理方法制备聚酰亚胺纤维,研究了不同热处理条件对聚酰亚胺纤维性能的影响。结果表明,采用定长处理和持续升温方式,真空氛围,热处理温度420℃,得到的聚酰亚胺纤维性能较好,其断裂强度达5.06 cN/dtex。     

聚酰亚胺及其纤维的研究与开发进展(Ⅰ)

从聚酰亚胺的制备原理、工艺、改性、应用等方面综述了聚酰亚胺(PI)的合成与发展,并着重介绍了聚酰亚胺纤维的国内外研究与应用进展,指出了聚酰亚胺及其纤维今后的发展方向。     

聚酰亚胺及其纤维的研究与开发进展(Ⅱ)

从聚酰亚胺的制备原理、工艺、改性、应用等方面综述了聚酰亚胺(PI)的合成与发展,并着重介绍了聚酰亚胺纤维的国内外研究与应用进展,指出了聚酰亚胺及其纤维今后的发展方向。     

聚酰亚胺薄膜及纤维的探索研究

利用均苯四甲酸二酐(PMDA)、4,4'-二氨基二苯醚(4,4'-ODA)和自制三单体在强极性非质子有机溶剂N,N-二甲基乙酰胺(DMAc)中进行共缩聚反应,制得高粘度的聚酰胺酸(PAA)溶液,经涂膜、热亚胺化,得到坚韧透明的聚酰亚胺(PI)薄膜,其具有较好的拉伸断裂强度和合适的伸长率;同时将得到的PAA溶液进行湿法纺丝,制成PAA纤维,采用热亚胺化和高温拉伸的方法制得PI纤维,其断裂强度能达到3.67cN/dtex。     

聚酰亚胺初生纤维的形态结构

以聚酰亚胺浓溶液为纺丝浆液 ,以乙醇及其与水的混合物为凝固浴 ,采用干湿法纺丝工艺路线纺制聚酰亚胺纤维。用扫描电子显微镜研究了初生纤维形态结构 ,发现聚酰亚胺初生纤维的内部孔洞较小 ,而且受凝固浴配比的影响也较小。同时发现聚酰亚胺干湿法成形过程中存在轻微的原纤化现象     

含砜基聚酰亚胺的合成及其中空纤维膜的制备（英文）

以4,4'-(六氟异丙烯)二酞酸酐(6FDA)与4,4'-双(4-氨基苯氧基)二苯砜(BAPS)为反应单体,以N-甲基-2-吡咯烷酮(NMP)为溶剂,合成了聚酰胺酸(PAA),将PAA溶液采用流延成膜的方法制备成薄膜;另外,将PAA溶液采用干-湿法纺丝工艺制得PAA中空纤维膜,再将PAA薄膜及其中空纤维膜在300℃左右的高温热环化制得6FDA-BAPS型聚酰亚胺(PI)膜。研究了6FDABAPS型PI及其中空纤维膜的结构与性能。结果表明:所合成的6FDA-BAPS型PI为目标产物,其在NNP、N,N-二甲基乙酰胺、四氢呋喃中具有良好的溶解性能。6FDABAPS型PI中空纤维膜外皮层致密、支撑层疏松多孔,该中空纤维膜具有较高的热学性能和力学性能,在氮气氛围中热失重5%的温度为511℃,断裂强度为26.5 MPa。     

聚酰亚胺薄膜的酰亚胺化方法

本文介绍了聚酰亚胺薄膜的两种酰亚胺化方法,即热酰亚胺化(HIM)和化学酰亚胺化(CIM)方法。指出了目前我国生产厂家所采用的热酰亚胺化法的不足之处。阐述了化学酰亚胺化法的优点及其研发途径。指出我们只有走自主研发和技术创新之路,进行具有产业化前途的,高效的聚酰亚胺薄膜化学酰亚胺化技术的开发,才能适应日益增长的高新技术的发展需要。     

非等温热重法测定聚酰胺酸纤维亚胺化动力学参数

二步法制备聚酰亚胺时,亚胺化过程至关重要,可使聚酰胺酸脱水成为聚酰亚胺。该文对三元共聚得到的聚酰胺酸溶液进行湿法纺丝后的纤维进行了亚胺化动力学参数的测定,采用非等温热重法得到聚酰胺酸 TG 曲线,根据 Free-man-Carroll 动力学算法求算得到其亚胺化反应级数为一级,活化能为47．56 kJ /mol,频率因子 A 的自然对数为10．23。     

共聚聚酰亚胺纤维的制备及其性能研究

采用4,4’-二氨基二苯醚和1,6-己二胺(HDA)为二胺单体,与均苯四甲酸酐(PMDA)在二甲基乙酰胺(DMAc)中共聚得到聚酰胺酸(PAA)纺丝原液,通过干法纺丝工艺路线纺制PAA初生纤维,利用热酰亚胺化制备了共聚型聚酰亚胺(PI)纤维;通过红外光谱分析、动态力学分析、热重分析、X射线衍射等手段分析了PI纤维的力学性能及热性能。结果表明:红外光谱分析发现HDA的长亚甲基链引入到PI的链中;当HDA质量分数为20%时,PI纤维的断裂强度和模量分别为5.1 cN/dtex和76 cN/dtex;动态力学和热重分析发现,纤维的玻璃化转变温度为315～380℃,热稳定性在400℃以上;纤维经热处理后聚集态结构存在一定的有序性。     

Characteristics of polyimide ultrafine fibers prepared through electrospinning

A novel route for making polyimide sub‐micron fibers is described. The ultrafine fibers are prepared by electrospinning a poly(amic acid) solution, a precursor of polyimide, followed by thermal imidization. The fiber diameters, which are much smaller than conventionally spun fibers, range from a few tens of nanometers to several micrometers. A rectangular cross‐section is observed in the case of sub‐micron fibers with a cross‐sectional dimension below ～500 nm. © 2003 Society of Chemical Industry     

Simulation of dry‐spinning process of polyimide fibers

As one type of high‐performance fibers, the polyimide fibers can be prepared from the precursor polyamic acid via dry‐spinning technology. Unlike the dry‐spinning process of cellulose acetate fiber or polyurethane fiber, thermal cyclization reaction of the precursor in spinline with high temperature results in the relative complex in the dry‐spinning process. However, the spinning process is considered as a steady state due to a slight degree of the imidization reaction from polyamic acid to polyimide, and therefore a one‐dimensional model based on White‐Metzer viscoelastic constitutive equation is adopted to simulate the formation of the fibers. The changes of solvent mass fraction, temperature, axial velocity, tensile stress, imidization degree, and glass transition temperature of the filament along the spinline were predicted. The effects of spinning parameters on glass transition temperature and imidization degree were thus discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and characterisation of polyamide–polyimide organoclay nanocomposites

BACKGROUND: Ternary nanocomposites containing an organomodified layered silicate polyimide additive within a polyamide matrix have been investigated to gain greater insight into structure–property relationships and potential high‐temperature automotive applications. RESULTS: Polyamide nanocomposite blends, containing 3 wt% of organoclay, were prepared and compared with organoclay‐reinforced polyamide and neat polyamide. Nanoclay addition significantly increased heat distortion temperature, as well as both the tensile and flexural moduli and strength. The addition of polyimide demonstrated further increases in heat distortion temperature, glass transition temperature and the flexural and tensile moduli by about 17, 21 and 40%, respectively. The tensile and flexural strengths were either unaffected or decreased modestly, although the strain‐to‐failure decreased substantially. Morphological studies using transmission electron microscopy (TEM) and X‐ray diffraction showed that the nanoclay was dispersed within the ternary blends forming highly intercalated nanocomposites, regardless of the presence and level of polyimide. However, TEM revealed clay agglomeration at the polyamide–polyimide interface which degraded the mechanical properties. CONCLUSIONS: A range of improvements in mechanical properties have been achieved through the addition of a polyimide additive to a polyamide nanocomposite. The decrease in ductility, arising from the poor polyamide–polyimide interface and nanoclay clustering, clearly requires improving for this deficiency to be overcome. Copyright © 2008 Society of Chemical Industry     

纳米芳纶增强聚酰亚胺气凝胶纤维的制备及其性能研究

以3,3',4,4'-联苯四甲酸二酐和1,4-二氨基苯二胺共聚制备聚酰胺酸盐前驱体溶液,通过湿法纺丝,然后经过超临界二氧化碳干燥和热亚胺化处理制得纳米芳纶(ANFs)增强聚酰亚胺(PI)气凝胶纤维(简称PI/ANFs气凝胶纤维),研究了气凝胶纤维的结构与性能.结果表明:傅里叶变换红外光谱和X射线衍射光谱表征所制备的PI...