3,3',4,4'-联苯四甲酸二酐的合成研究

以4-氯-邻苯二甲酸酐为原料,经酯化、偶联、水解、脱水合成标题化合物。目标化合物须保存在真空干燥箱中,防止水分倾入。通过改进工艺路线,可得到高收率、高纯度的目标产物,使工业化生产成为可能,为全芳香族聚酰亚胺的生产提供高质量原料。     

Synthesis,characterization, and kinetic study on the thermal decomposition of polyamidoethers

Some new polyamidoethers have been synthesized by condensation reaction of N,N'-dichloroacetyl-1,4-phenylene-diamine with bisphenols (4,4'-isopropylidenediphenol, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, and 4,4'-dihydroxybiphenyl) in N-methylpyrrolidone medium using DB-24-Crown-8 as a phase-transfer catalyst. The structure of these polymers has been characterized by infrared (i.r.) and ¹H nuclear magnetic resonance (NMR) spectroscopy. Kinetic method of thermal decomposition of these polymers and their 2% mixture with polyvinylchloride (PVC) has been studied.     

Synthesis and properties of new poly(amide‐imide)s based on 1,3‐bis[4,4'‐(trimellitimido) phenoxy] propane and aromatic diamines

Six new poly(amide‐imide)s 8a–f containing trimethylene moiety in the main chain were synthesized by the polycondensation reactions of 1,3‐bis[4,4'‐(trimellitimido) phenoxy] propane 6 with six different aromatic diamines 7a–f in a medium constituting N‐methyl‐2‐pyrrolidone, triphenylphosphite, CaCl₂, and pyridine as condensing agents. The polycondensation reaction produced a series of novel poly(amide‐imide)s 8a–f in high yields with inherent viscosities between 0.35 and 0.63 dL/g. The resulting poly(amide‐imide)s were characterized by elemental analysis, viscosity measurements, thermal gravimetric analysis (TGA and DTG), solubility tests, and FTIR spectroscopy. 1,3‐Bis[4,4'‐(trimellitimido) phenoxy] propane 6 as a new monomer containing trimethylene moiety was synthesized using a three‐step reaction. At first 1,3‐bis[4,4'‐nitrophenoxy] propane 3 was prepared by the reaction of 4‐nitrophenol 1 with 1,3‐dibromo propane 2 in DMF solution . Then, dinitro 3 was reduced to 1,3‐bis[4,4'‐aminophenoxy] propane 4 by using a solution of sodium sulfite in ethanol. Finally, 1,3‐bis[4,4'‐(trimellitimido) phenoxy] propane 6 was prepared by the reaction of one equivalent diamine 4 with two equivalents of trimellitic anhydride 5 in a mixture of acetic acid‐pyridine (3 : 2). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis,characterization and end-use evaluation of epoxy resins prepared from diallyl and dipropyl bisphenol A

We have synthesized 2,2'(6')-diallyl-4,4'-isopropylidenediphenol (diallyl bisphenol A), 2,2'(6')-dipropyl-4,4'-isopropylidenediphenol (dipropyl bisphenol A), and epoxy resins (glycidyl ether oligomers) of different average molecular weights. The acrylic and methacrylic esters were prepared by reacting the epoxy resin with acrylic and methacrylic acids, respectively. The amine-cured epoxy resins showed promise as general-purpose adhesives, while the epoxy acrylates were found to be useful as reactive oligomers in ultraviolet (UV) radiation curable coatings, and the epoxy methacrylates as anaerobic adhesives.     

基于三维框架材料H3PW6Mo6O40/Zn(BDC)(4,4'-Bipy)0.5高效吸附亚甲基蓝

采用溶剂热法,用H3PW6Mo6O40对金属有机骨架Zn(BDC)(4,4'-Bipy)05进行改性,制备出金属有机骨架复合材料H3PW6Mo6O40/Zn(BDC)(4,4'-Bipy)0.5.利用IR、XRD、TG、SEM对其结构进行分析.同时,以亚甲基蓝溶液模拟染料废水进行吸附实验,考察了初始pH、温度对吸附容量的影响,探究了其吸附等温线和动力学特征.实验结果表明,H3PW6Mo6O40/Zn(BDC)(4,4'-Bipy)05对亚甲基蓝有很好的吸附性能,在20℃和pH 2的条件下,吸附量达588.24mg/g,且该吸附符合Langmuir等温吸附模型和拟二级动力学方程,吸附过程自发且放热.     

冠醚修饰的紫精类化合物的合成与电化学性能研究

将苯并氮杂-15-冠-5的边臂链接到4,4'-联吡啶上,设计合成了3种冠醚环修饰的紫精化合物。运用紫外光谱考察了其识别碱金属离子的能力,运用循环伏安测试考察了其电化学氧化还原性质。紫外光谱测试结果显示,含有两个冠醚环的紫精化合物对金属离子有较显著的配位作用。循环伏安测试结果显示,氯化1,1'-双[2-酮-2-(苯并氮杂-15-冠-5)]-4,4'-联吡啶盐化合物具有更好的电化学信号,出现了两对可逆的氧化还原峰。     

Synthesis and characterization of polyester-imides from imidodicarboxylic acid monomers and ethylene glycol

Two monoimidodicarboxylic acids and four diimidodicarboxylic acids were synthesized from trimellitic anhydride and amino compounds, viz., glycine, p-aminobenzoic acid, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl methane, and 4,4'-diaminodiphenyl sulfide, and characterized by IR and ¹H-NMR spectroscopies and melting-point determination. These functional monomers were condensed in N-methyl-2-pyrrolidone solvent with ethylene glycol by a transesterification reaction to obtain the novel polyester-imides with backbones of alternate imide-ester linkages or imide-imide-ester-ester linkages with ? SO₂? , ? O? , ? CH₂? , or ? S? S? bridges in between. All the polymers were characterized by IR and ¹H-NMR spectroscopies, X-ray diffraction, solution viscosity, solubility and solubility parameters, and differential thermal analysis. Most of the polymers possess amorphous structure and fairly high decomposition temperatures (450–485°C). These polymers having solubility parameters in the range δ 11.44–11.85, as determined by the group contribution technique, are soluble at room temperatures in aprotic polar solvents. © 1993 John Wiley & Sons, Inc.     

Effect of tetraacid on the properties of ODPA/4,4′‒ODA polyimide foams

In this research, a new flexible polyimide (PI) foams was successfully prepared and characterized based on precursor powder foaming. This foams were derived from 3,3',4,4'‒oxydiphethalic anhydride (ODPA), 3,3',4,4'‒oxydiphethalic tetraacid (ODPA‒tetraacid), and 4,4'‒oxydianiline (4,4'‒ODA). With varying molar percentage of ODPA‒tetraacid in (ODPA + ODPA‒tetraacid), the changes of properties of PI precursor powders and PI foams were comparatively investigated. The foaming processes of PI foams were observed by a self‒made visualization device. The decomposition products of precursor powders were analyzed by thermogravimetry‒Fourier transform infrared spectroscopy (TG‒FTIR). The crystallinity of precursor powders was investigated by wide‒angle X‒ray diffraction (WXRD). The chemical structure of PI precursor powders and foams was analyzed by FTIR. The thermal properties of PI foams were tested by the methods of dynamic mechanical analysis (DMA), and TG/differential thermogravimetry (DTG) analysis. The cell structure of PI foams was observed by a scanning electron microscopy. The rebound resilience of PI foams was studied by a self‒made drop‒ball instrument. With the increasing of ODPA‒tetraacid, the inflation onset temperatures and inflation degrees of PI foams decreased from 210°C to 118°C and increased from 10 to 14.8 times, respectively. The crystallinity of PI precursor powders increased. The thermal stability of PI foams decreased. The cell structure of PI foams became more uniform and the rebound rates increased linearly. Besides, ODPA‒tetraacid did not yield any negative effect on the complete imidization of the PI precursor powder by the FTIR spectra. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Poly(Aryline imides) as E-beam resist: Sensitivity and resolution

Polyamic acids synthesized from di-trifluoromethyl methane bis(phthalic anhydride) and 4,4'-diaminophyenyl sulfone (F-1) and 4,4'-diaminophenyl ether (F-4) were found to have excellent negative E-beam resist properties. The best materials contain about 90 percent imidized structural units having sensitivities of 1.5 to 2.5 μC cm^?2 and contrast of 1.0 to 1.3. Polyamic acid of pyromellitic dianhydride and 4,4'-diaminophenyl sulfone (P-1) imidized to 97 percent exhibits useful positive E-beam resist properties. Radiation induces imidization and chain scission to alter the solubility of the resist polymers resulting in the formation of latent images.     

H_6P_2Mo_(15)W_3O_(62)修饰三维金属有机骨架Cu(BDC)(4,4'-Bipy)_(0.5)吸附亚甲基蓝

采用溶剂热法,在合成金属有机骨架Cu(BDC)(4,4'-Bipy)_(0.5)的过程中引入活性组分H_6P_2Mo_(15)W_3O_(62),制备出一种新型吸附剂H_6P_2Mo_(15)W_3O_(62)/Cu(BDC)(4,4'-Bipy)_(0.5)。利用IR、XRD、BET、SEM对其结构进行分析,进而研究其亚甲基蓝的吸附性能。研究结果表明,H_6P_2Mo_(15)W_3O_(62)/Cu(BDC)(4,4'-Bipy)_(0.5)对亚甲基蓝有很好的吸附性能,在40℃和pH 2的条件下吸附量达78.8 mg/g。H_6P_2Mo_(15)W_3O_(62)/Cu(BDC)(4,4'-Bipy)_(0.5)对亚甲基蓝的吸附符合Langmuir等温吸附型和拟二级动力学模型,吸附过程是一个自发和吸热过程。     

一类含甲基结构高透明聚酰亚胺的合成与性能研究

以2,6-二氨基甲苯、3,3'',4,4''-联苯四甲酸二酐、3,3'',4,4''-二苯醚四甲酸二酐为原料，间甲酚作为溶剂，经一步法高温共缩聚，制备一系列可溶性共聚型聚酰亚胺(MPI)。利用红外光谱（FTIR）、核磁共振波谱（1H NMR）、差式扫描量热仪（DSC）、热重分析仪（TGA）和紫外-可见光分度计（UV）等测试仪器对MPI进行结构与性能表征。结果表明：红外与核磁的数据说明成功合成了含甲基结构的聚酰亚胺；该系列的含甲基聚酰亚胺在室温下可溶于N-甲基吡咯烷酮（NMP）、N,N-二甲基乙酰胺（DMAc）、二氯甲烷（CH2Cl2）三氯甲烷（CHCl3）、二甲基亚砜（DMSO）等有机溶剂，具有良好的溶解性和成膜性，并随着联苯酐的含量增加溶解性降低；同时该系列MPI制得的薄膜具有良好的光学透过性能，在紫外光波长450 nm时的透过率均在74%以上，截止波长在350 nm左右；该系列MPI的起始分解温度均大于457 ℃，800 ℃氮气氛围中的焦炭产率均大于63%，玻璃化转变温度在260 ℃~285 ℃之间，表现出优异的热学性能。此外，MPI-1~MPI-4薄膜还具有良好的机械性能，其弹性模量在1.7~2.1 GPa，拉伸强度在89.7~120.6 MPa，断裂伸长率在19.7%~28.4%。     

一类高透明含氟共聚型聚酰亚胺的合成与表征

以2,2′-双(三氟甲基)-4,4′-二氨基联苯(TFMB)、4,4-二氨基二苯醚(ODA)和3, 3′,4,4′-二苯醚四甲酸二酐(ODPA)为原料,间甲酚为溶剂,按不同的配比,采用一步法制备了一系列低成本含氟共聚型聚酰亚胺CPI-1～CPI-4,进一步制备成膜。通过红外光谱仪、核磁共振波谱仪对该系列含氟聚酰亚胺的结构进行了表征确认。采用UV光度计、TGA、DSC、拉伸性能试验机对其溶解性能、光学性能、热性能、机械性能进行了测试。结果表明,该系列含氟聚酰亚胺室温下能溶于二甲基亚砜(DMSO)、N,N-二甲基乙酰胺(DMAc)、三氯甲烷(CHCl_3)等有机溶剂,具有较好的溶解性和成膜性。所制薄膜具有优良的光学透明性,在紫外光波长400nm时的透光率均在70%以上。CPI-1～CPI-4的起始分解温度均大于500℃,N_2氛围下800℃的质量残留百分数均在52%以上,玻璃化转变温度在166～170℃。此外,CPI-1～CPI-4薄膜的拉伸强度在89.8～105.3MPa,弹性模量在1.3～1.7 GPa,断裂伸长率在9.7%～18.4%,表现出较好的机械性能。     

Initial evaluation of novel polyamide-imides and their copolymers as adhesives

—An adhesive screening study was performed at NASA Langley Research Center on two linear aromatic polyamide-imide (PAI) homopolymers and two linear aromatic PAI copolymers. The homopolymers were made with either of two amide diamines, 3,3'- or 4,4'-diaminobenzanilide (DABA), and 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA). The two copolymers studied were prepared with a combination of 3,3'-DABP and amide diamines. These aromatic PAIs possess high thermal stability because of intermolecular hydrogen bonding and chain stiffness. Lap shear strength (LSS) tests, conducted at room temperature, 177, 204 and 232°C, were the primary criterion for evaluation of the polymers as adhesives. Included in the study were measurements of the glass transition temperature made on fractured specimens for each bonding condition and a visual determination of the type of bond failure for specimens at each test temperature. Of the four adhesive candidates investigated, the best LSS values were obtained with the PAI copolymer identified as LARC-TPI(25% 3,3'-DABA). However, the LSS values were higher for the LARC-TPI polyimide with which the adhesive strengths were compared. The combination of a high molecular weight and the increased interchain electronic interaction associated with the amide group appears to contribute to the poor flow properties observed.     

Detection of cocoa butter equivalents in chocolate

The fatty acids at the sn-2 position and the sterol composition of cocoa butter and three common cocoa butter equivalents (CBE), namely Coberine, Choclin and Calvetta, were studied comparatively, in order to develop a sensitive method for detecting CBE in chocolate. Differences observed in the composition of saturated fatty acids at position-sn-2 present some interest in detecting CBE in chocolate. Differences found in 4-desmethyl and 4-methylsterol compositions, although quite significant, did not present any practical interest because of the relatively small amounts present in CBE. The 4,4′-dimethylsterol or triterpene alcohol fraction was found to have a potential for determining CBE in chocolate. Thus, the triterpene alcohols of Coberine were further fractionated on argentation thin layer chromatography (TLC) and analyzed by gas liquid chromatography (GLC) and gas chromatography-mass spectrometry (GC-MS). α-Amyrin was found in 48.2% of the triterpene alcohols of Coberine and was absent from cocoa butter. Cycloartenol, the main 4,4′-dimethylsterol of cocoa butter, and α-amyrin were well resolved on an OV-17 glass capillary column.     

Thermomechanical characterization of thermoplastic polyimides containing 4,4'‐methylenebis(2,6‐dimethylaniline) and polyetherdiamines

In this work, we synthesized polyimides by incorporating an aromatic diamine monomer with a methylene linker, 4,4'‐methylenebis(2,6‐dimethylaniline) (MBDMA), to make a robust main chain along with aliphatic polyetherdiamine backbone linkers to reduce rigidity. We designed the polymers to exhibit thermal properties in between those of conventional aromatic polyimides and polymers with wholly aliphatic ether diamine links. Through dynamic mechanical analysis and differential scanning calorimetry, it is shown that control of the molar ratios of the aromatic MBDMA (4,4'‐methylenebis(2,6‐dimethylaniline)) and the composition and size of the aliphatic polyetherdiamine can be used to tune the glass transition. The polymers were characterized by GPC, FTIR, NMR, thermomechanical and calorimetric analysis, and microhardness testing. POLYM. ENG. SCI., 59:221–232, 2019. © 2018 Society of Plastics Engineers     

Thiophene π‐bridge effect on photovoltaic performances of dithienosilole and bithiazole backboned polymers

In this article, two dithienosilole (DTS) and bithiazole (BTz) backboned donor–acceptor (D‐A) copolymers with (poly{5‐(5‐(4,4‐bis(2‐ethylhexyl)‐4H‐silolo[3,2‐b:4,5‐b']dithiophen‐2‐yl)thiophen‐2‐yl)‐4,4'‐dinonyl‐5'‐(thiophen‐2‐yl)‐2,2'‐bithiazole} (PDTS‐DTBTz)) and without (poly{5‐(4,4‐bis(2‐ethylhexyl)‐4H‐silolo[3,2‐b:4,5‐b']dithiophen‐2‐yl)‐4,4'‐dinonyl‐2,2'‐bithiazole} (PDTS‐BTz)) thiophene π‐bridge were synthesized to study the influence of thiophene π‐bridge on their photovoltaic performances. Both polymers show similar band gap, but polymer with thiophene π‐bridge (PDTS‐DTBTz) has a higher molecular weight, narrower polydispersity index (PDI), more planar geometry, higher crystallinity, higher hole mobility, and better miscibility with fullerene (polymer solar cells (PSCs) acceptor). Although PDTS‐BTz polymer based PSCs devices show higher open circuit voltage (V_oc), PDTS‐DTBTz polymer does show higher power conversion efficiency (PCE) with improved short circuit current density (J_sc) and fill factor (FF). The present results indicate that thiophene π‐bridge does contribute to the PSCs performances of dithienosilole and bithiazole backboned copolymer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42798.     

Investigations on the synthesis of polyimides with coronand structure via tandem Diels-Alder addition polymerization

The tandem Diels-Alder polymerization of 11 bismaleimides with 4,4'-dimethyl-6,6'-(octamethylene)di-2-pyrone was investigated. Polymers with coronand structure were formed only in case of bismaleimides possessing flexible spacer groups; rigid spacer groups led to network formation.     

Synthesis and characterization of novel soluble poly(ether ketone sulfone)s with pendant polychloro groups

A novel monomer of tetrachloroterephthaloyl chloride (TCTPC) was prepared by the chlorination of terephthaloyl chloride catalyzed by ferric chloride at 175–180°C for 10 h and confirmed by FTIR, MS, and elemental analysis. Five new polychloro substituted poly(aryl ether ketone sulfone)s (PEKSs) with inherent viscosities of 0.68–0.75 dL/g have been prepared from 4,4′‐diphenoxydiphenylsulfone, 4,4′‐bis(2‐methylphenoxy) diphenylsulfone, 4,4′‐bis(3‐methylph‐enoxy)diphenylsulfone, 4,4′‐bis(2,6‐dimethylphenoxy)diphenylsulfone, and 4,4′‐bis(1‐naphthoxy)‐diphenylsulfone with TCTPC by electrophilic Friedel‐Crafts acylation in the presence of DMF with anhydrous AlCl₃ as a catalyst in 1,2‐dichloroethane, respectively. These polymers having weight–average molecular weight in the range of 76,600–83,900 are all amorphous and show high glass transition temperatures ranging from 213 to 250°C, the 5% weight loss temperature over 450°C, high char yields of 60–67% at 700°C in nitrogen and good solubility in CHCl₃ and polar solvents such as DMF, DMSO, and NMP at room temperature. All the polymers formed transparent, strong, and flexible films, with tensile strengths of 85.1–90.8 MPa, Young's moduli of 2.52–3.24 GPa, and elongations at break of 21.2–27.2%. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Porous polyimide films obtained by using lithium chloride as pore‐forming agent

Porous polymer films have been obtained from polyimide based on benzophenonetetracarboxylic dianhydride and 4,4'‐diamino‐3,3'‐dimethyl‐diphenylmethane by incorporating lithium chloride (LiCl) in the poly(amidic acid) precursor and subsequently leaching out the maximum possible LiCl by water Soxhlet extraction for 6 h. The resulting porous polyimide films were characterized with regard to their pore size, thermal stability and dielectric properties. The morphology of the porous polyimide films showed a uniform distribution and various pore sizes depending on the initial quantity of added pore‐forming agent. © 2013 Society of Chemical Industry     

Residues of organic contaminants in beeswax

Residues of the varroacides amitraz, chlordimeform, chlorfenvinphos, bromopropylate, coumaphos, tetradifon, acrinathrin, and fluvalinate, the organic microcontaminants 4,4'‐DDE, 4,4'‐TDE, PCB 153 and PCB 180, and the lipophilic pesticides lindane, chlorpyrifos and endosulfan have been determined by GC/MS in 52 beeswax samples. Recoveries on spiked samples ranged from 93 to 108% and determination limits varied from 4 to 65 µg/kg. Lindane (0.042–0.29 mg/kg), chlorfenvinphos (0.16–7.62 mg/kg), 4,4'‐TDE (0.20 mg/kg), bromopropylate (0.041–0.12 mg/kg), tetradifon (0.032–0.58 mg/kg), acrinathrin (0.058–0.59 mg/kg), coumaphos (0.27–0.38 mg/kg), fluvalinate (0.064–5.10 mg/kg), endosulfan sulfate (0.12–0.37 mg/kg) and 3‐phenoxybenzaldehyde, a degradation product of fluvalinate and acrinathrin (0.080–1.47 mg/kg), were the compounds detected in beeswax. Foundation beeswax sheets contained higher contaminant concentrations and a greater diversity of compounds in relation to comb beeswaxes. Repeated melting in boiling water of purified beeswax spiked with the contaminants did not substantially modify the content of most of the contaminants in beeswax, except for amitraz and chlordimeform, showing that the contaminants are stable and remain practically unchanged in the purified beeswax.