PEI纳米纤维增强PMMA透光材料

利用同轴共纺技术制备了芯层为聚醚酰亚胺(PEI),壳层为聚甲基丙烯酸甲酯(PMMA)的复合纳米纤维无纺布,在PEI熔点以下,利用热压技术将壳层的PMMA熔融构成复合材料的树脂基体,PEI纳米纤维成为PMMA树脂基体中的纤维增强体。通过对复合纳米纤维结构和热力学特性的研究表明,同轴共纺技术有效解决了PEI静电纺丝困难的问题,芯层PEI结构形貌良好并均匀分布于复合纳米纤维中,结合复合材料的力学性能、断面分析和透光性能表征,结果表明,当PEI质量分数在2%~3%时,复合材料的拉伸强度提高幅度接近25%,而复合材料的可见光透过率仅比纯PMMA材料下降了9%,仍具有良好的透光性能。     

MWNTs增强PA6纳米纤维透光复合材料的制备

利用同轴共纺技术制备PMMA/PA6壳芯结构的复合纳米纤维,在芯层PA6纤维中添加经过表面处理的MWNTs,并且利用热压成型技术将壳层的PMMA部分熔融成为透光复合材料的树脂基体,而PA6纤维成为纤维增强体.由于PA6纤维中MWNTs的存在,PA6纤维的力学性能明显提高,作为透光复合材料的纤维增强体进一步提高了复合材料的拉伸性能,同时基本保持了原有的PMMA/PA6透光复合材料的可见光透过率.     

PEI功能化复合纤维膜的制备及其电化学性能

采用静电纺丝技术制备了五种聚乙烯亚胺(PEI)含量的醋酸纤维素/聚乙烯吡咯烷酮复合纤维膜。利用扫描电镜、红外光谱等手段对膜材料进行了表征,比较了PEI掺杂量对复合纤维膜形貌的影响。将这些复合纤维膜组装到玻碳电极表面,利用循环伏安电化学研究了这些膜电极的在弱酸/强酸下的电催化放氢性能。结果表明,PEI功能化的复合纤维膜电极的电催化放氢性能显著增强。     

PMMA透光复合材料研究进展

综述了以聚甲基丙烯酸甲酯(PMMA)为树脂基体的透光复合材料研究进展,对该种复合材料的改性、制备以及成型加工技术进行了分析和研究,讨论了现今PMMA透光复合材料制备成型、加工工艺对最终材料的透光率、力学性能以及其他性能的影响.同时,分析了同轴共纺静电纺丝技术在PMMA透光复合材料制备上的可行性.实验结果表明,由于尺寸效应,纳米纤维可在不影响复合材料透光率的前提下,明显提高复合材料的力学性能.     

利用同轴射流技术制备PMMA/PC透光复合材料

利用同轴射流技术制备了聚甲基丙烯酸甲酯(PMMA)及聚碳酸酯(PC)的复合透光材料。同轴共纺技术制备的壳芯复合纳米纤维具有壳层PMMA及芯层PC的有效结构,在特定温度下,芯层PC无序纳米纤维成为壳层熔融PMMA树脂基体中的增强体。扫描电镜和透射电镜结果显示,复合纳米纤维的表面形貌良好,具有壳芯结构的复合纳米纤维均匀分布于无纺布中。热压成型技术制备的复合材料力学性能和光学性能结果表明,由于增强体PC纳米纤维的尺寸效应,复合材料的力学性能明显提高,当PC含量为4%时,材料的拉伸强度提高了17%,且当PC含量控制在3%以内时,复合材料透光性能的下降值可控制在10%以内。     

溶液参数对静电纺丝PAN@PS复合纳米纤维形貌及结构的影响

采用同轴静电纺丝技术,以聚丙烯腈(PAN)溶液为核层、聚苯乙烯(PS)溶液为壳层,制备了PAN@PS复合纳米纤维。研究了纺丝液浓度、溶剂种类对PAN@PS复合纳米纤维形貌和结构的影响。结果表明:PS/四氢呋喃(THF)作为壳层溶液的复合纳米纤维(PAN@PS/THF)可获得相界面清晰的同轴纤维。随PS纺丝液浓度的增加,纤维的直径先增大后有所减小,整体呈现递增的趋势,当PS/THF质量分数为20%时,纤维直径约为693 nm且表面光滑。而以质量分数为20%的PS/二甲基甲酰胺(DMF)为壳层溶液的复合纳米纤维(PAN@PS/DMF)直径有所增加且纤维表面凹凸不平,呈现双相连续的结构。因此,在静电纺丝过程中,可以通过改变纺丝液的参数来调节纤维的形貌和结构。     

中国专利

<正>一种高耐热聚合物纳米复合纤维薄膜制备方法本发明利用静电纺丝技术成功制得高耐热纳米级复合纤维薄膜,属于薄膜的改性领域。方法如下:分别制备聚偏氟乙烯和聚醚酰亚胺溶液,将聚偏氟乙烯与聚醚酰亚胺按质量比为9∶1混合得到均相纺丝溶液。利用静电纺丝技术将所制均相纺丝溶液进行纺丝成膜,烘干,即得到热稳定性能高的聚偏氟乙烯/聚     

Ultem PEI生产更舒服美观的工作服

<正>日本毛织株式会社的全新工作服系列,使用了沙伯基础创新塑料的Ultem聚醚胺纤维。沙伯基础创新塑料已广受认可的Ultem树脂技术的应用,近期再度延伸——Ultem聚醚酰亚胺(PEI)纤维成功应用于高端工作服和防护服。     

电纺丝技术制备无机/有机复合纳米纤维的研究进展

静电纺丝法是一种利用聚合物溶液或熔体在强电场中进行喷射纺丝的加工技术,是获得纳米尺寸长纤维的有效方法之一。目前电纺丝技术逐渐转移到无机/有机纳米复合纤维的制备方面。回顾了近年来电纺丝技术制备无机/有机复合纳米纤维的研究进展,包括:半导体纳米粒子/聚合物复合纳米纤维的制备,无机氧化物纳米粒子/聚合物复合纳米纤维的制备以及贵金属纳米粒子/聚合物复合纳米纤维的制备。     

NiB/PVDF-PVA纳米纤维催化剂的制备及其应用

通过静电纺丝技术首先制备了Ni Cl2/PVDF-PVA复合高分子纳米纤维,通过原位还原法得到了PVDF-PVA复合纳米纤维负载Ni B的非晶态合金催化剂,并把该催化剂用于Na BH4水解制氢反应。SEM表征表明,Ni Cl2/PVDF-PVA复合纳米纤维具有纤细微观纳米形貌,纤维直径均匀,介于50²00 nm。TG分析表明,Ni Cl2/PVDFPVA纳米纤维可以稳定到大约390℃,超过该温度纳米纤维开始发生热解,说明该纳米纤维催化剂载体具有适于硼氢化钠水解反应的热稳定性。接触角测试表明,PVA共纺显著提高了PVDF纳米纤维的亲水性,有利于Na BH4和水分子在催化剂表面上的接触反应。水解制氢实验表明,PVA共混静电纺丝法得到的Ni B/PVDF-PVA较Ni B/PVDF催化剂催化活性显著提高,该催化剂具有较好的应用前景。     

Preparation of aligned polyetherimide fiber by electrospinning

Fifteen to 20 wt % polyetherimide (PEI) solutions with 1-methyl-2-pyrrolidinone (NMP) were prepared. The electrical conductivity and surface tension of the solutions were determined. The fiber spinning technique of electrospinning was optimized in order to prepare unidirectionally aligned, structurally oriented nanofiber tows. The morphology of the PEI fibers was investigated using field emission scanning electron microscopy (FESEM). The well-aligned fibers with diameters between 0.58 and 0.90 μm (FESEM) were collected by electrospinning 20 wt % PEI solutions with NMP in the range of 8–10 kV onto a target rotating with a surface velocity 9.8 m/s. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Electrospun composite fibers of polyvinylpyrrolidone with embedded poly(methyl methacrylate)–polyethyleneimine core–shell particles

Composite fibers consisting of poly(methyl methacrylate)–polyethyleneimine (PMMA–PEI) core–shell particles embedded in polyvinylpyrrolidone (PVP) were successfully fabricated by the electrospinning method. The electrospun fibers were produced using 18?% w/v aqueous PVP solution blended with 2?% w/v PMMA–PEI particles at various pH (1, 2, 3, and 4) with a fiber collection distance set at 10?cm. The applied electrical voltages (10, 12, 14, and 16?kV) significantly affected the morphology and diameter of the prepared composite fibers (141–353?nm). The smallest composite fibers were obtained from the spinning mixture at pH 2 and a voltage of 14?kV. The composite fibers would potentially be applied as drug and bioactive compound carriers.     

Dynamic mechanical modeling of PEI/dicyanate semi‐IPNs

The dynamic mechanical behavior of polyetherimide(PEI)/dicyanate semi‐interpenetrating polymer networks (semi‐IPNs) was analyzed by using the conventional Takayanagi model for the sea‐island morphology (PEI content of 10% or below) and a polyhedron model, which we developed for the dicyanate nodular structure (PEI content of 20% or above). The model parameters for the Takayanagi model were determined by the volume fraction of the PEI dispersed phase and Kerner's equation, while the model parameters for the polyhedron model were simply calculated by introducing a phase continuity factor. Both models correlate well with the morphology revealed in the micrographs except near the transition temperature of the PEI‐rich phase. The additional shift toward higher temperature found in the nodular structure was due to the intermixed phase composition, and the effect was quantified by measuring the calorimetric transition temperature. The dynamic mechanical modeling for the dual‐phase morphology (PEI content of 15%) and for the semi‐IPNs showing a morphology spectrum were also successfully accomplished by combining the Takayanagi model and the polyhedron model.     

Effect of reinforcing glass fibers on morphology and properties of thermoplastic modified epoxy-aromatic diamine matrix

A usual way to improve the fracture toughness of thermosetting polymers consists of using an initially miscible thermoplastic that phase separates at a particular conversion, depending on composition and reaction temperature. This work deals with the effect of glass reinforcing fibers on the morphologies of polyetherimide and aminografted polyetherimide toughened epoxy-diamine systems. The presence of fibers in these systems does not affect the phase separation process, but the final morphology changes in the case where polyetherimide (PEI) is used as an additive. Furthermore, the use of aminografted PEI does not change the previously observed morphology. In terms of mechanical properties, the use of fibers leads to a great improvement in the fracture energy, indicating that good adhesion between fiber and matrix is also achieved. Polym. Compos. 25:368–374, 2004. © 2004 Society of Plastics Engineers.     

Effect of tertiary polysiloxane on the phase separation and properties of epoxy/PEI blend

Epoxy functional siloxane (DMS-E09) was blended with epoxy resin (DGEBA) and thermoplastic polyetherimide (PEI). The results of morphology monitoring indicated that the reaction induced phase separation for all blends followed the spinodal phase separation mechanism. The microstructure changed from co-continuous of 25 wt% epoxy/PEI system to phase-inversion structure of 30 wt% epoxy/PEI system regardless of the content of the tertiary component DMS-E09. By comparing the onset time of phase separation between the two designated systems, the sequential occurrence of primary macrophase separation in co-continuous phase and secondary microphase separation in PEI-rich phase for 25 wt% epoxy/PEI system was identified. Studies of the thermomechanical properties of the DGEBA/PEI/DMS-E09 blends found that storage modulus increased with the addition of PEI but decreased with DMS-E09 monotonically. The value of T_g decreased with the addition of the tertiary DMS-E09 but was offset partially by the presence of PEI.     

Fabrication and characterization of solution cast MWNTs/PEI nanocomposites

Under mild conditions with the aid of ultrasonic, multi‐walled carbon nanotubes (MWNTs) have been functionalized by mixed acid treatment which was proved by FTIR and XPS. According to SEM, acid treatment on MWNTs decreased the thickness of the membrane. However, no devastating damage and fracture happened on MWNTs after acid treatment under mild conditions. Precipitation observation illustrated that the enhanced solubility of MWNTs in water, ethanol, and dimethylformaide (DMF). Further, MWNTs/polyetherimide (PEI) nanocomposite films have been prepared by the simple solution casting method. The dispersion of MWNTs in polyetherimide (PEI) matrix was observed by Atomic Force Microscopy (AFM) which illustrated the improved dispersion for acid treated MWNTs in PEI. The adding of MWNTs in PEI decreased the dispersive component of surface energy and increased the polar component of surface energy, which resulted in the decrement of film surface energy. Differential scanning calorimetry showed that the glass transition temperature of PEI increased by about 4°C after the introduction of MWNTs. This improvement was related to the better affinity between MWNTs and PEI matrix, which also resulted in the improvement of mechanical strength in MWNTs/PEI nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Structuring and characterization of a novel highly microporous PEI/BMI semi-interpenetrating polymer network

Syntheses of semi-interpenetrating polymer networks (semi-IPNs) with polyetherimide/bismaleimide (PEI/BMI) chromophore composites showing molecular sieve characteristics are reported. A tunable and compatible chemical structure with fine morphology was obtained through in situ controlled sol-gel polymerization, crosslinking, chemical modification and membrane fabrication. The novel semi-IPN synthesized and assembled using ethanol as polar protic modifier and pore former, had superior structure and morphology for making gas separation membranes. These semi-IPN membranes gave 15 times higher gas flux than those membranes prepared from pure PEI without significant decrease in gas selectivity. The chemical structures of these novel semi-IPNs were elucidated by FTIR, XPS and SEM. It appears that in situ simultaneous ethoxylation, anionic polymerization of BMI and imide modifications were responsible for creating the new chemical structure and molecular morphology that was different from traditional BMI resins. In addition, these chemical processes give superior structures using green chemistry techniques such as ambient temperature reaction and polymerization without initiators.     

聚醚酰亚胺对炭黑填充环氧树脂复合材料导电性能和吸波性能的影响

利用反应诱导方法设计制备了炭黑(CB)包覆环氧树脂(EP)微球/聚醚酰亚胺(PEI)(EP/PEI/CB)复合材料。研究了该复合材料的微观结构,测量了其导电性能及在Ka波段的吸波性能,并与CB填充EP(EP/CB)复合材料进行了对比。结果表明,在EP/PEI/CB中,CB选择性分布在PEI相中并形成较规则的立体网状连续相,EP为30μm左右大小的微球分散相,与EP/CB相比具有更低的体积电阻率。EP/PEI/CB属于一种谐振腔式吸波体,在33～40 GHz范围具有较好的吸波性能且优于EP/CB,最大吸收峰出现在35.61 GHz,峰值反射率(R)为–17.40 dB,吸收带宽3.22 GHz(R–10 dB).     

Effects of processing conditions on foaming behaviors of polyetherimide (PEI) and PEI/polypropylene blends in microcellular injection molding process

Foaming behaviors of both neat polyetherimide (PEI) and PEI/polypropylene (PP) blends were studied in this article in microcellular injection molding (Mucell) process. The study mainly focused on the comparison of two materials' foaming behaviors under different processing conditions which took a critical effect on the morphologies of foams. The results indicated that the different characteristics of PEI and PEI/PP blends, such as melt strength, gas dissolvability, and solubility, induced different nucleation ability of PEI and PEI/PP blends. The addition of PP could obviously improve the cell density and reduce the cell size. With the processing conditions changing, the morphologies of PEI/PP altered more variously, and their distribution of cell density was wider. This suggested that foaming behaviors of PEI/PP blends was more flexible to be controlled by the processing conditions than neat PEI. The effects of shot size, gas injection, and injection rate on foam morphologies were studied in detail. Shot size determined the weight reduction of samples and affected the cell density and size significantly. Gas dosing time and dosing rate determined the gas ratio which effected on foam morphologies of the PEI and PEI/PP foams. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41443.     

Role of critical concentration of PEI in NMP solutions on gas permeation characteristics of PEI gas separation membranes

In preparation of polymeric gas separation membranes by phase inversion method, polymer concentration is one of the most important variables which can change membrane morphology and behavior. In this research, critical concentration of the polyetherimide (PEI) solutions in N-methyl-2-pyrrolidone (NMP) as a solvent was determined by viscometric method. The influence of temperature on critical concentration was studied. Three asymmetric PDMS/PEI membranes with different concentrations of PEI were prepared and characterized for H₂/CH₄ separation. The results showed that the membranes with higher concentrations than critical concentration were more suitable for gas separation. In addition, the viscosity data were fitted by appropriate equations and the densities were satisfactorily correlated by a simple first-order polynomial with respect to temperature and the PEI mass fraction. The prepared membrane showed the selectivity of 26 for H₂/CH₄ separation at 1 bar and 25 °C for pure gas and 24.8 for mixed gas. The influence of the pressure on the H₂ and CH₄ permeance and the selectivity for a mixed binary gas showed that the permeance of both gases declined by pressure enhancement and the selectivity increased.