BMI原位复合材料的研究

以BMI为基本组分,将原位复合材料用于BMI树脂的增韧,制备了BMI原位复合材料即RSM／PIO／BMI体系。详细研究了RSM／MIO／BMI未固化体系的反应性和固化树脂的力学性能、耐热性,用扫描电镜对固化树脂的断口形貌进行分析。结果表明,固化树脂宏观上呈现半透明状,微观上具有微纤维结构存在于基体聚合物中,正是由于这种特殊的增韧相结构的存在,导致改性RSM／PIO／BMI体系具有良好的抗冲击性能,冲击强度为17.6kJ/m^2。     

Synthesis and thermal properties of poly(urethane‐imide)

The synthesis and thermal properties of thermoplastic poly(urethane‐imide) (PUI) resins were studied. Model reaction studies on the reactions of 4,4′‐diphenylcarbamatodiphenylmethane and 4,4′‐diisocyanatodiphenylmethane with phthalic anhydride were performed. We found that the reaction of anhydrides with urethane groups could take place under certain reaction conditions. According to the model reaction studies, N‐2‐methyl‐pyrrolidone was employed as a solvent, and no catalyst was used in the polymerization. To restrain the side reaction of anhydrides with urethane groups, we adopted a two‐step chain‐extending procedure in a chain‐extending reaction. The inherent viscosity of PUI was 0.83–0.99 dL/g. The prepared polymers not only exhibited improved solubility in organic solvents but also formed flexible films. Thermogravimetric analysis showed that PUI exhibited a two‐step thermal weight‐loss pattern. The first step of the thermal degradation of PUI was attributed to the thermooxidizing cleavage of weak and labile linkage, such as urethane groups, isopropylidene, and methylene, except for imide rings. The polymer inherent viscosity decreased sharply during the first step of thermal degradation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 773–781, 2001     

对改性亚胺/环氧树脂体系潜伏性促进剂的研究

通过胶化时间测定和贮存粘度变化,研究了乙酰丙酮金属络合物对改性亚胺／环氧树脂体系的潜伏性促进作用。结果表明,乙酰丙酮铬对该体系有较好的潜伏性促进作用。     

Synthesis and Their Thermal and Thermo-Oxidative Properties of Poly(benzimidazole amide imide) Copolymers

In this study, the 3′-dinitrobenzidine was first reacted with excess isophthaloyl chloride form a monomer with dicarboxylic acid end group. Two types of aromatic dianhydride (viz. pyromellitic dianhydride (PMDA) and 3,3′,4,4′-sulfonyldiphthalic anhydride (DSDA)), were also reacted with excess 4,4′-diphenyl-methane diisocyanate to form polyimide prepolymers terminated with an isocyanate group. The prepolymers was further extended with the diacid monomer to form a nitro group containing aromatic poly(amide-imide) copolymers. The nitro groups in these copolymers were hydrogenated to form amine groups and cyclized at 180 ^○C, to form the poly(benzimidazole amide imide) copolymers in polyphosphoric acid which acted as a cyclization agent. The resulting copolymers can be soluble in sulfuric acid and polyphosphoric acid, in sulfolane under heating to 100 ^○C, and in polar solvent N-methyl-2-pyrrolidone under heating to 100 ^○C with 5% lithium chloride. From the DSC and TGA measurements, it demonstrated that the glass transition temperature of copolymers exhibits a range of 270∼322 ^○C. The 10% weight loss temperatures exhibits a range of 460∼541 ^○C in nitrogen, and 441∼529 ^○C in air, respectively. The activation energy and the integration parameter of degradation temperature of the copolymers were evaluated by the Doyle–Ozawa method. It indicated that these copolymers exhibited good thermal and thermo-oxidative stability with the increase of imide content.     

Preparation and characterization of unsaturated poly(ester‐imide) based on 1,4‐bis[2′‐trifluoromethyl‐4′‐(4″‐glycolformate)‐trimellitimidophenoxy]benzene

A novel diimidodialcohol monomer, 1,4‐bis[2′‐trifluoromethyl‐4′‐(4″‐glycolformate)‐ trimellitimidophenoxy]benzene (BGTB), was synthesized and characterized. It was reacted with isophthalic acid, maleic anhydride and propylene glycol to produce a novel unsaturated poly(ester‐imide) (BGTB‐UPEI) with imide and trifluoromethyl groups in the polymer backbone. The BGTB‐UPEI resin was diluted with reactive monomer (styrene) to give a low‐viscous poly(ester‐imide)/styrene (BGTB‐UPEI/St) mixed solution, which was then thermally cured to yield thermosetting BGTB‐UPEI/St composite. The effect of processing parameters such as the curing temperature and curing time, reactive monomer concentration and initiator amount on the curing reaction was systematically investigated. Experimental results indicated that the thermally cured BGTB‐UPEI/St composite exhibited much better thermal, mechanical, electrical insulating properties and chemical resistance than the standard unsaturated polyester/polystyrene composite. Copyright © 2006 Society of Chemical Industry     

Imide‐Functionalized Heteroarene‐Based n‐Type Terpolymers Incorporating Intramolecular Noncovalent Sulfur∙∙∙Oxygen Interactions for Additive‐Free All‐Polymer Solar Cells

The aggregation/crystallinity of classic n‐type terpolymers based on naphthalene diimide and perylene diimide is challenging to tune due to their rigid and extended cores, leading to suboptimal film morphology. A new strategy for developing high‐performance n‐type terpolymers by incorporating imide‐functionalized heteroarenes is reported here to balance crystallinity and miscibility without sacrificing charge carrier mobilities. The introduction of thienopyrroledione (TPD) into the copolymer f‐BTI2‐FT results in a series of terpolymers BTI2‐xTPD having distinct TPD content. The irregular backbone reduces crystallinity, yielding improved miscibility with the polymer donor. More importantly, TPD triggers noncovalent S?O interactions, increasing backbone planarity and in‐chain charge transport. Such interactions also promote face‐on polymer packing. As a result, all‐polymer solar cells (all‐PSCs) based on BTI2‐30TPD achieve an optimal power conversion efficiency (PCE) of 8.28% with a small energy loss (0.53 eV). This efficiency is substantially higher than that of TPD (4.4%) or a BTI2‐based copolymer (6.8%) and is also the highest for additive‐free all‐PSCs based on a terpolymer acceptor. Moreover, the BTI2‐30TPD cell exhibits excellent stability with the PCE retaining 90% of its initial value after 400 h of aging. The results demonstrate that random polymerization using imide‐functionalized heteroarenes is a powerful approach to develop terpolymer acceptors toward efficient and stable all‐polymer solar cell PSCs.     

Curing of epoxy resin using imide‐amines

The curing behavior of diglycidyl ether of bisphenol‐A (DGEBA) was investigated by differential scanning calorimetry, using varying molar ratios of imide‐amines and 4,4′‐diaminodiphenyl sulfone (DDS). The imide‐amines were prepared by reacting 1 mol of pyromellitic dianhydride (P) with excess (2.5 mol) of 4,4′‐diaminodiphenyl ether (E), 4,4′‐diaminodiphenyl methane (M), or 4,4′‐diaminodiphenyl sulfone (S) and designated as PE, PM, PS. Structural characterization was done using FTIR, ¹H NMR, ¹³C NMR spectroscopic techniques and elemental analysis. The mixture of imide‐amines and DDS at ratio of 0 : 1, 0.25 : 0.75, 0.5 : 0.5, 0.75 : 0.25, and 1 : 0 were used to investigate the curing behavior of DGEBA. The multiple heating rate method (5, 10, 15, and 20°C/min) was used to study the curing kinetics of epoxy resins. The peak exotherm temperature was found to be dependent on the heating rate, structure of imide‐amine, and also on the ratio of imide‐amine : DDS used. Activation energy was highest in case of epoxy cured using a mixture of DDS : imide‐amine of a ratio of 0.75 : 0.25. Thermal stability of the isothermally cured resins was also evaluated in a nitrogen atmosphere using dynamic thermogravimetry. The char yield was highest in case of resins cured using mixture of DDS : PS (0.25 : 0.75; EPS‐3), DDS : PM (0.25 : 0.75; EPM‐3), and DDS : PE (0.75 : 0.25; EPE‐1). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3502–3510, 2006     

Electrochemistry of ionophore-coordinated Cs and Sr ions in the tri-1-butylmethylammonium bis((trifluoromethyl)sulfonyl)imide ionic liquid

The selective extraction of Cs⁺ and Sr²⁺ from aqueous solutions by using the ionophores calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) and dicyclohexano-18-crown-6 (DCH18C6), respectively, was demonstrated in the hydrophobic, room-temperature ionic liquid (RTIL), tri-1-butylmethylammonium bis((trifluoromethyl)sulfonyl)imide (Tf₂N⁻). The electrochemistry of Cs⁺ coordinated by BOBCalixC6 and Sr²⁺ coordinated by DCH18C6 was examined at a mercury film electrode (MFE) in this ionic liquid by using cyclic staircase voltammetry, sampled current voltammetry at a rotating electrode, and chronoamperometry. Both BOBCalixC6·2Cs⁺ and DCH18C6·Sr²⁺ exhibit well-defined reduction waves at approximately −2.4 and −2.9 V versus the ferrocene/ferrocenium (Fc/Fc⁺) couple, respectively, in which the coordinated ions are reduced to their respective amalgams, permitting the recycling of the ionophores. The diffusion coefficients of BOBCalixC6·2Cs⁺ and DCH18C6·Sr²⁺ are (2.7 ± 0.1) × 10⁻⁹ and (2.1 ± 0.1) × 10⁻⁹ cm² s⁻¹, respectively, at 30 °C. The coulometric efficiency for the reduction and stripping of Cs at mercury pool electrodes was about 90% and was independent of the deposition time, whereas the efficiency for Sr was slightly less than 90% at short times and decreased with the deposition time, probably due to the formation of a passive layer of Sr(Tf₂N)₂.     

Synthesis and properties of new aromatic poly(ester‐imide)s derived from 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl) pyridine and various dihydroxy compounds

A novel class of wholly aromatic poly(ester‐imide)s, having a biphenylene pendant group, with inherent viscosities of 0.32–0.49 dL g^?1 was prepared by the diphenylchlorophosphate‐activated direct polyesterification of the preformed imide‐ring‐containing diacid, 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine (1) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. A reference diacid, 2,6‐bis(trimellitimido)pyridine (2) without a biphenylene pendant group and two phenylene rings in the backbone, was also synthesized for comparison purposes. At first, with due attention to structural similarity and to compare the characterization data, a model compound (3) was synthesized by the reaction of compound 1 with two mole equivalents of phenol. Moreover, the optimum condition of polymerization reactions was obtained via a study of the model compound synthesis. All of the resulting polymers were characterized by Fourier transform infrared and ¹H NMR spectroscopy and elemental analysis. The ultraviolet λ_max values of the poly(ester‐imide)s were also determined. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, chloroform, tetrahydrofuran, and m‐cresol, as well as in polar organic solvents, such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide. The crystalline nature of the polymers obtained was evaluated by means of wide‐angle X‐ray diffraction. The resulting poly(ester‐imide)s showed nearly an amorphous nature, except poly(ester‐imide) derived from 4,4′‐dihydroxy biphenyl. The glass transition temperatures (T_g) of the polymers determined by differential scanning calorimetry thermograms were in the range 298–342 °C. The 10% weight loss temperatures (T_10%) from thermogravimetric analysis curves were found to be in the range 433–471 °C in nitrogen. Films of the polymers were also prepared by casting the solutions. Copyright © 2006 Society of Chemical Industry     

Microwave‐promoted rapid synthesis of new optically active poly(amide imide)s derived from N,N′‐(pyromellitoyl)‐bis‐L‐isoleucine diacid chloride and aromatic diamines

A pyromellitic dianhydride (benzene‐1,2,4,5‐tetracarboxylic dianhydride) was reacted with L ‐isoleucine in acetic acid, and the resulting imide acid [N,N′‐(pyromellitoyl)‐bis‐L ‐isoleucine] (4) was obtained in a high yield. 4 was converted into N,N′‐(pyromellitoyl)‐bis‐L ‐isoleucine diacid chloride by a reaction with thionyl chloride. The polycondensation reaction of this diacid chloride with several aromatic diamines, including 1,4‐phenylenediamine, 4,4′‐diaminodiphenyl methane, 4,4′‐diaminodiphenylsulfone (4,4′‐sulfonyldianiline), 4,4′‐diaminodiphenylether, 2,4‐diaminotoluene, and 1,3‐phenylenediamine, was developed with two methods. The first method was polymerization under microwave irradiation, and the second method was low‐temperature solution polymerization, with trimethylsilyl chloride used as an activating agent for the diamines. The polymerization reactions proceeded quickly and produced a series of optically active poly(amide imide)s with good yields and moderate inherent viscosities of 0.17–0.25 dL/g. All of the aforementioned polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of these optically active poly(amide imide)s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 951–959, 2004