Thermal and mechanical properties of poly(urethane‐imide)/epoxy/silica hybrids

Improving properties of polyurethane (PU) elastomers have drawn much attention. To extend the properties of the modified PU composite, here a new method via the reaction of poly(urethane‐imide) diacid (PUI) and silane‐modified epoxy resin (diglycidyl ether of bisphenol A) was developed to prepare crosslinked poly (urethane‐ imide)/epoxy/silica (PUI/epoxy/SiO₂) hybrids with enhanced thermal stability. PUI was synthesized from the reaction of trimellitic anhydride with isocyanate‐terminated PU prepolymer, which was prepared from reaction of polytetramethylene ether glycol and 4,4′‐diphenylmethane diisocyanate. Thermal and mechanical properties of the PUI/epoxy/SiO₂ hybrids were investigated to study the effect of incorporating in situ SiO₂ from silane‐modified epoxy resin. All experimental data indicated that the properties of PUI/epoxy/SiO₂ hybrids, such as thermal stability, mechanical properties, were improved due to the existence of epoxy resin and SiO₂. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

分散介质法合成聚酯酰亚胺

本文采用乙二醇为分散介质合成了二种聚酯酰胺亚胺。实验证明，只要工艺合理、大量醇的存在对酰亚胺化反应没有影响；在高温下通过酯交换脱出乙二醇分散介质然后用熔融缩聚法完成酯化反应。该方法具有工艺简单，不需要合成中间体，也不使用高价溶剂的优点。     

Synthesis and characterization of rubbery highly fluorinated siloxane–imide segmented copolymers

The synthesis and characterization of a series of poly(siloxane–imide) block (or segmented) copolymers obtained by copolymerization of amine‐terminated polydimethylsiloxane with fluorinated aromatic compounds containing anhydride and amine functionality are reported. New fluorinated block copolymers have been synthesized to obtain organophilic polyimides potentially interesting for molecular membrane separations. The new aspects of this work relative to the literature are (1) a comparison of solution and solid‐state approaches in the imidization step to generate the target poly(siloxane–imide) copolymers and (2) exploration of new compositions involving fluorinated aromatic polymers derived from added diamine compounds. It is shown that the copolymer properties can be tailored from glassy to rubbery materials by varying the amount and the type of oligosiloxane used; the transition between glassy and rubbery properties is characterized at a siloxane content of 60 wt%. As a main result, it is shown that the solid‐state approach for inducing the cyclo‐imidization step is the more efficient one for synthesizing polymers with good mechanical properties, when the amount of siloxane block is increased in the copolymer series. Physical and chemical methods (thermogravimetric analysis, Fourier transform infrared spectroscopy, viscosity measurements) were used to characterize the copolymer properties obtained according to the two different synthesis routes. The obtained siloxane–imide copolymers are well soluble in a large variety of moderately polar solvents and exhibit very good thermal stability up to 400 °C. Hence the prepared copolyimides would seem to be promising candidates as organophilic membranes as well as gas permeation membranes. © 2012 Society of Chemical Industry     

Processable and colorless fluorinated poly(ether imide)s based on an isopropylidene‐containing bis(ether anhydride) and various aromatic bis(ether amine)s bearing trifluoromethyl groups

A series of novel organosoluble and light‐colored fluorinated poly(ether imide)s (PEIs) ( IV ) having inherent viscosities of 0.43–0.59 dL/g were prepared from 4,4′‐[1,4‐phenylenbis(isopropylidene‐1,4‐phenyleneoxy)]diphthalic anhydride ( I ) and various trifluoromethyl‐substituted aromatic bis(ether amine)s by a standard two‐step process with thermal and chemical imidization of poly(amic acid) precursors. These PEIs showed excellent solubility in many organic solvents and could be solution‐cast into transparent and tough films. These films were essentially colorless, with an UV–visible absorption edge of 361–375 nm and a very low b* value (a yellowness index) of 15.3–17.0. They also showed good thermal stability with glass‐transition temperature of 191–248°C, 10% weight loss temperature in excess of 494°C, and char yields at 800°C in nitrogen more than 39%. The thermally cured PEI films showed good mechanical properties with tensile strengths of 83–96 MPa, elongations at break of 8–11%, and initial moduli of 1.7–2.0 GPa. They possessed lower dielectric constants of 3.25–3.72 (1 MHz). In comparison with the V series nonfluorinated PEIs, the IV series showed better solubility, lower color intensity, and lower dielectric constants. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 620–628, 2007     

Synthesis and properties of some novel,soluble and light‐coloured,aromatic poly(amide–imide) copolymers

A new type of tetraimide‐dicarboxylic acid (I) was synthesized starting from the ring‐opening addition of m‐aminobenzoic acid (m‐ABA), 4,4′‐oxydiphthalic anhydride (ODPA) and 4,4′‐methylenedianiline (MDA) at a 2:2:1 molar ratio in N‐methyl‐2‐pyrrolidone (NMP), followed by cyclodehydration to the diacid I. A series of soluble and light‐coloured poly(amide–imide–imide)s (III_a–j) was prepared by triphenyl phosphite‐activated polycondensation from the tetraimide‐diacid I with various aromatic diamines (II_a–j). All films cast from DMAc had cutoff wavelengths shorter than 400 nm (376–393 nm) and had b* values between 20.46 and 40.67; these polymers were much lighter in colour than those of the corresponding trimellitimide series. All polymers were readily soluble in a variety of organic solvents such as NMP, N,N‐dimethylacetamide, dimethyl sulfoxide, and even in the less polar m‐cresol and pyridine. Compared with those of corresponding ODPA–MDA polyimide, the solubilities of poly(amide–imide–imide)s III_a–j were greatly improved. Polymers III_a–j afforded tough, transparent, and flexible films, which had tensile strengths ranging from 82 to 105 MPa, elongations at break from 8 to 14%, and initial moduli from 2.0 to 2.2 GPa. The glass transition temperature of polymers were recorded at 255–288 °C. They had 10% weight loss at a temperature above 540 °C and left more than 60% residue even at 800 °C in nitrogen. © 2002 Society of Chemical Industry     

N-(取代苯基)马来海松酸酰亚胺的合成及表征

松香树脂酸衍生物具有广泛的生物活性。该文以松香为原料,在催化剂对甲基苯磺酸作用下与马来酸酐经Diels-Alder反应制得马来海松酸;马来海松酸与取代苯胺采用一步法在N,N-二甲基甲酰胺(DMF)溶剂中,于155℃反应4 h,合成了8个具有潜在生物活性的N-(取代苯基)马来海松酸酰亚胺化合物,产率为42.5%~84.8%;对产物结构进行了IR、1HNMR、13CNMR光谱表征确认。     

Thermally stable polyureas and poly(urea‐imide)s containing zinc and nickel napthtrien complexes

Two new napthtrien metal complexes, MNapth₂trien; where M = Zn and Ni, were synthesized and used for the synthesis of metal‐containing polyureas and poly(urea‐imide)s. MNapth₂trien underwent polymerization reaction with two diisocyanates, namely, 4,4′‐diphenylmethane diisocyanate and isophorone diisocyanate to yield polyureas. Poly(urea‐imide)s were obtained by the synthesis of metal‐containing isocyanate‐terminated polyurea prepolymers from the reaction between MNapth₂trien and excess diisocyanates, which could then undergo further reaction with different dianhydrides. The dianhydrides used were pyromellitic dianhydride and benzophenone‐3,3′,4,4′‐tetracarboxylic dianhydride. The polymers were characterized by infrared, nuclear magnetic resonance, elemental analysis, X‐ray diffraction, solubility, and viscosity. Glass transition temperature of the polymers was obtained from differential scanning calorimetry and dynamic mechanical thermal analysis. Thermal stability of polymers was studied by thermogravimetric analysis in air. It was found that the resulting metal‐containing polymers exhibited good thermal stability. Initial decomposition temperatures of the polymers depend on the amount of MNapth₂trien in the polymer composition. Char yields of metal‐containing poly(urea‐imide)s are higher than those of metal‐containing polyureas. Most metal‐containing polymers show good solubility in organic solvents. Shore D hardness test indicates that metal‐containing poly(urea‐imide)s are hard materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Profile of extended chemical stability and mechanical integrity and high hydroxide ion conductivity of poly(ether imide) based membranes for anion exchange membrane fuel cells

We designed and synthesized a poly(ether imide) (PEI) membrane that has good chemical and mechanical stabilities. Alkalized PEI (A-PEI) membrane was fabricated by solution casting of chloromethylated PEI (CM-PEI) followed by quaternization and alkalization. The chemical structure of the synthesized polymers was verified by proton nuclear magnetic resonance (¹H NMR) and Fourier-transform infrared spectroscopy (FT-IR). Physiochemical properties of the membrane such as ion exchange capacity, water uptake, and swelling ratio were investigated. The membranes with a high degree of chloromethylation (DC) exhibited elevated hydroxide ion conductivity in range of 6.7–44.2 mS/cm at 90 °C under 100% relative humidity (RH). The hydrophilic-hydrophobic phase separation was verified by atomic force microscope (AFM) and small angle X-ray scattering (SAXS) measurements. Chemical stability was evaluated by measuring the durability of membranes while they were soaked in oxidative and alkaline solutions at 60 °C for 200 h.     

预测乙烷/离子液体系统溶解平衡的UNIFAC模型

采用UNIFAC模型对乙烷在1-烷基-3-甲基咪唑双三氟甲基磺酰亚胺盐([RMIm][Tf2N],R=乙基(E)、丁基、己基、辛基(O)、癸基)离子液体中的113个溶解度数据进行关联,得到了乙烷与主基团CH2—和[MIm][Tf2N]间的交互参数,建立了预测乙烷在该类离子液体中溶解度的UNIFAC模型。利用该模型预测了乙烷在[EMIm][Tf2N]和[OMIm][Tf2N]两种离子液体中的溶解度,预测值与文献值吻合较好,平均误差分别为4.01%和3.81%,最大误差为9.86%。将该模型用于分析改变烷基链长对乙烷在[RMIm][Tf2N]离子液体中溶解度的影响发现,在烷基链长较短时,增加其链长可有效提高乙烷的溶解度;但当烷基链长较长时,其效果减弱。该模型可对乙烷在该类离子液体中的溶解度进行有效预测,为其相关的传质分离过程提供相平衡数据。