Synthesis and photodegradation of poly[2,5-bis(dimethylsilyl)furan]

Summary Poly[2,5-bis(dimethylsilyl)furan] (V), a copolymer with alternating furan and disilyl units, has been prepared by the Wurtz coupling of 2,5-bis(dimethylchlorosilyl)furan (II) with sodium metal dispersion in toluene. Lower molecular weight poly[2,5-bis(dimethylsilyl)furan] (IV) has been prepared by a similar condensation reaction with 2,5-bis(dimethylfluorosilyl)furan (III). IV and V have been characterized by ¹H, ¹³C and ²⁹Si NMR, IR, and UV spectroscopy as well as by GPC, TGA and elemental analysis. Photolysis of V in a benzene/methanol solution results in degradation of the polymer.     

Synthesis and photodegradation of poly[2,5-bis(dimethylsilyl)thiophene]

Summary Poly[2,5-bis(dimethylsilyl)thiophene] (I), a copolymer with alternating thiophene and disilyl units, has been prepared by the Wurtz coupling of 2,5-bis(dimethylchlorosilyl)thiophene (IV) with sodium metal in toluene. I has been characterized by ¹H, ¹³C, and ²⁹Si NMR, IR, UV, GPC, TGA and elemental analysis. The photolysis of I in benzene/methanol solution results in degradation of the polymer. The structure of the photoproducts and possible mechanisms for their formation are discussed.     

Synthesis and properties of poly(amide-imide)s based on 1,5-bis(4-trimellitimido)naphthalene

1,5-Bis(4-trimellitimido)naphthalene (II) was prepared by the condensation reaction of 1,5-naphthalenediamine and trimellitic anhydride. A series of aromatic poly(amide-imide)s (IV _a–o) was synthesized by the direct polycondensation of the diimide-diacid (II) and various aromatic diamines (III _a–o). The reaction utilized triphenyl phosphite and pyridine as condensing agents in the presence of calcium chloride in N-methyl-2-pyrrolidone (NMP). The inherent viscosities of the resulting poly(amide-imide)s were in the range of 0.55∼1.39 dL/g. These polymers were generally soluble in polar solvents, such as N,N-dimethylacetamide (DMAc), NMP, N,N-dimethylformamide (DMF). Flexible and tough poly(amide-imide) films were obtained by casting from a DMAc solution and had tensile strengths of 90∼145 MPa, elongations to break of 5∼13 %, and initial moduli of 2.29∼3.73 GPa. The glass transition temperatures of some poly(amide-imide)s were recorded in the range of 206∼218 °C, and most of the polymers did not show discernible glass transition on their DSC traces. The 10% weight loss temperatures were above 522 °C in nitrogen and above 474 °C in air atmosphere.     

1,4-二氯甲氧基丁烷的合成

以1,4-丁二醇和多聚甲醛为原料,制备一种无致癌毒性的氯甲基化试剂—1,4-二氯甲氧基丁烷。实验结果表明最佳反应条件为:1,4-丁二醇:多聚甲醛:无水氯化钙=9∶6.5∶7.0(质量比),加盐酸75 mL、硫酸100 mL、苯15 mL,常温下反应5 h,目标产物的产率达到75%以上。经试验证明所制备的氯甲基化试剂可以使白球氯甲基化,其氯含量达到17%。     

Synthesis and characterization of polyimides from 1,4-bis[4-(n-alkyloxy)phenyloxy]pyromellitic dianhydrides and 4,4'-oxydianiline

Summary New pyromellitic dianhydrides having (n-alkyloxy)phenyloxy (-O-Ph-O-n-C_mH_2m+1, m=1,4,8,12) side chains were synthesized and polymerized with 4,4'-oxydianiline (ODA) in NMP at room temperature. Imidization was carried out using triethylamine and acetic anhydride. The synthesized polyimides (C_m-OPIs) were characterized and their properties were measured and discussed in respect to the effects of side chains. Inherent viscosities of the polymers were in the 0.46 – 0.68 dL/g range. All the polymers were highly soluble in N-methylpyrrolidinone (NMP) and slightly soluble in DMSO, m-cresol, DMF and concentrated H₂SO₄ at room temperature. TGA pyrograms showed two-step degradation. In DSC thermograms the polymers exhibited T_g's between 219°C and 305°C and melting points near 350°C were observed in C₈- and C₁₂-OPIs. Wide-angle X-ray diffractometry for as-polymerized samples revealed very low crystallinities and layered structures which were better developed in the polymers with longer side chains. Received: 11 November 1997/Revised version: 4 December 1997/Accepted: 9 December 1997     

双对二甲氨基苯甲醛缩1,4-二(3-氨基丙基)哌嗪希夫碱的合成工艺及抑菌活性研究

以对二甲氨基苯甲醛(DMAB)和1,4-二(3-氨基丙基)哌嗪(BAPP)为原料,通过缩合反应合成了一个新的DMAB-BAPP希夫碱.利用正交试验确定了最佳合成工艺条件,即反应温度50℃,反应时间4h,DMAB与BAPP投料摩尔比是2.1∶1,在此条件下,产物收率为83.7％.通过琼脂扩散法测定了产物的抑菌性能,结果表...     

1,4-二(对氟苯甲酰基)苯的合成与纯化

1,4-二(对氟苯甲酰基)苯是合成聚芳醚酮的单体之一,采用付-克酰化反应合成了1,4-二(对氟苯甲酰基)苯,并采用红外光谱(IR)、元素分析、差示扫描量热仪(DSC)和核磁共振谱(1H-NMR)对产物结构进行了表征。     

1，4-双（对氟苯甲酰）苯及其聚合物的合成

以二硫化碳为溶剂、无水三氯化铝作催化剂、对苯二甲酰氯与氟苯为反应原料，在20℃利用Friedel-crafts酰基化反应合成了产率为76．7％、纯度为99．758％的1，4-双（对氟苯甲酰）苯（P，P-BFB）。经IR、^1HNMR和MS光谱对其结构分析，确定为P，P-BFB。以二苯砜为溶剂，在无水碳酸钾／碳酸钠的催化下，以P，P-BFB为单体与对苯二酚进行亲核取代反应合成了特性粘度为0．87的聚醚醚酮酮（PEEKK）。通过IR、DSC、TG和XRD对其结构与性能进行了表征，确定其结构为PEEKK；TG测试表明在氮气气氛下开始分解温度为557℃，且到1200℃时也没分解完全；DSC和XRD衍射图表明其为半晶态聚合物，且由DSC曲线可知其熔点Tm为367℃。     

Thermal decomposition behavior of poly[3,3-bis(ethoxymethyl) oxetane] and related polyethers

The thermal decomposition behavior of poly[3,3-bis(ethoxymethyl)oxetane] (polyBEMO) was examined and compared to the decomposition of poly(ethylene oxide) (PEO) and poly(tetramethylene oxide) (polyTHF). Differential scanning calorimetric (DSC) studies as a function of heating rates and at constant temperature as a function of time yielded activation energies of 45–50 kcal/mol, characteristic of polyether decomposition. First-order decomposition kinetics were found. The reaction is endothermic, with a heat of decomposition of 18.6 kcal/mol. Effusion mass spectroscopy on polyBEMO showed major peaks at 112, 140, 168, and 174 amu. A mechanism is proposed in which the thermal scission of the ether bonds in both the polymer chain and in the appendanges initiates the decomposition. The main decomposition reaction for polyBEMO can be written as where the appendages and main chain are cleaved in an unknown order.     

超声法制备1,4-双(二甲基硅基)苯

以THF为溶剂,对二溴苯与Mg在超声辐照下反应得到格式试剂,然后与二甲基一氯硅烷反应制得1,4-双(二甲基硅基)苯(BDSB),并用质谱、红外光谱、紫外光谱等对产物进行了表征.     

Synthesis and characterization of new organo-soluble poly(amide-imide)s based on 1,4-bis(trimellitimido)-2,5-dimethylbenzene

Summary A series of new aromatic poly(amide-imide)s were synthesized by the triphenyl phosphite activated polycondensation of the diimide-diacid, 1,4-bis(trimellitimido)-2,5-dimethylbenzene (I), with various aromatic diamines. The poly(amide-imide)s had inherent viscosities of 1.13–2.22 dL/g. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents. Transparent, flexible, and tough films of these polymers could be cast from DMAc or NMP solutions. Their cast films had tensile strengths ranging from 64 to 116 MPa, elongations at break from 6 to 20%, and initial moduli from 2.18 to 3.90 GPa. The glass transition temperatures of these polymers were in the range of 247–324°C. Received: 13 April 1999/Revised version: 28 May 1999/Accepted: 26 June 1999     

Synthesis,electrical and optical properties of multifunctional poly[2-(2-ethyl-hexyloxy)-1,4-phenylenevinylene]

Summary Branched monoalkoxy-substituted poly[2-(2-ethylhexyloxy)-1,4-phenylenevinylene] (EH-PPV) was prepared in thin films via the water-soluble precursor technique and solution elimination method. These precursor polymer films could be stretched up to 8 times, and the drawn films of the EH-PPV could be doped with I₂ and FeCl₃ to give conductivities of 5.28x10^-3 and 0.56 S/cm, respectively. The third-order nonlinear optical susceptibility of the polymer was determined by using third harmonic generation (THG) method at 1907 nm, fundamental wavelength. Measured ⁽³⁾(–3; ,,) value was 3.8x10^-12 esu. The maximum emission wavelength of EH-PPV film in photoluminescence spectrum was 560 nm, corresponding to the yellowish red color.     

Preparation of brush-like crystals of poly[2,6-(1,4-phenylene)-benzobisimidazole]

Poly[2,6-(1,4-phenylene)-benzobisimidazole] (PPBI) crystals were prepared by using reaction-induced crystallization of oligomers during solution polymerization of 1,2,4,5-tetraaminobenzene and diphenyl terephthalate. Polymerizations were carried out at a monomer concentration of 4.3 × 10⁻² mol L⁻¹ at 350 °C for 6 h. Brush-like PPBI crystals were obtained in a mixture of structural isomers of dibenzyltoluene, in which many needle-like crystals came out vertically from the surface of the ribbon-like crystals. Average width and thickness of the ribbon-like crystals were 0.75 μm and 0.11 μm, respectively. And average length and diameter of the needle-like crystals were 0.36 μm and 50 nm, respectively. The brush-like crystals possessed high crystallinity and exhibited good thermal resistance. The ribbon-like crystals were formed by the crystallization of imidazole oligomers at an initial stage of polymerization, and then the needle-like crystals grew from the surface of the ribbon-like crystals. Polymerization occurred on the crystals when the oligomers were crystallized, leading to the high molecular weight PPBI crystals.     

Synthesis and characterization of poly(1,4-dihydroxyanthraquinone terephthalate)

A novel polymeric dye containing an anthraquinone ring was prepared by solution polycondensation. The molecule geometry was fully optimized on the basis of the AM1 method. The hydrogen bond was formed and retained coplanarity in the molecular structure. In its UV spectrum, a large hypsochromic shift and a hypochromic effect were observed due to polyesterification. The polymeric dye was also characterized by means of IR and TG. Its thermal degradation mechanism was elucidated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2246–2248, 2001     

Synthesis and properties of poly (1,4-cyclohexanedicarboxylic anhydride)

Summary Polyanhydrides from cycloaliphatic 1,4-Cyclohexanedicarboxylic acid (1,4-CHDA) were synthesized by melt polycondensation and characterized by WAXD, FTIR and DSC. The results show that these polymer displayed strong crystallinity with highly melting point and can't be dissolved in common solvents. The polymers, which come from different original isomer conformation CHDA, show different melting point and DSC curve. The isomerization happened during the polymerization and reached an equilibrium point at last. By melt polycondensation, the high cis-isomer content polyanhydride is difficult to obtained. Received: 24 May 2000/Revised version: 4 September 2000/Accepted: 6 September 2000     

Synthesis and electrical properties of poly[2-(2-(4-trifluoromethyl)phenyl)ethenyl-1,4-phenylenevinylene] and PPV copolymers

Summary Poly[2-(2-(4-(trifluoromethyl)phenyl)ethenyl)-5-methoxy-1,4-phenylenevinylene] (PFEMPV) and a series of PPV copolymers containing 1,4-phenylenevinylene (PV) units were synthesized through a water-soluble precursor route, and their electrical and third-order nonlinear optical properties were studied. The PFEMPV films could not be doped with I₂, but FeCl₃-doped films showed an electrical conductivity of 5.0x10^-4 S/cm. The conductivities of FeCl₃-doped copolymer films ranged from 2.0x10^-3 to 2.0 S/cm depending on their copolymer compositions. The third-order nonlinear optical susceptibility, ⁽³⁾(–;,,–), was also investigated by the degenerate four wave mixing technique at 602 nm. The ⁽³⁾ value of PFEMPV was 6.9x10^-11 esu. The photoluminescence spectrum of PFEMPV shows its emission maximum at 550 nm.     

Synthesis and characterization of new soluble cardo poly(amide-imide)s derived from 2,2-bis[4-(4-trimellitimidophenoxy)phenyl]norbornane

A series of new soluble poly(amide-imide)s were prepared from the diimide-dicarboxylic acid, 2,2-bis[4-(4-trimellitimidophenoxy)phenyl]norbornane, and various diamines by the direct polycondensation in N-methyl-2-pyrrolidinone containing CaCl_2, using triphenyl phosphite and pyridine as condensing agents. All the polymers were obtained in quantitative yields with inherent viscosities of 1.01-1.42 dL g⁻¹. Gel permeation chromatography (GPC) of the polymers showed number-average and weight-average molecular weight up to 67,300 and 118,000, respectively. The poly(amide-imide)s were amorphous and were readily soluble in various solvents such as N-methyl-2-pyrrolidinone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), pyridine, cyclohexanone and tetrahydrofuran. Tough and flexible films were obtained by casting their DMAc solution. The films had tensile strength of 89-110 MPa and a tensile modulus range of 1.8-2.2 GPa. The glass transition temperatures of the polymers were determined by DSC method and they were in the range of 265-295 °C. The polymers were fairly stable up to a temperature around or above 450 °C, and lose 10% weight in the range of 472-504 °C and 490-520 °C in nitrogen and air, respectively.     

N,N’-二硝基-N,N’-二(3-([1,2,3]-三唑并[4,5-c]呋咱-4,5-内盐-5-基)呋咱-4-基)二氨基甲烷的合成与表征

以二氨基呋咱(DAF)为起始原料,经Caro's acid氧化、锌粉还原、环化、缩合和硝化五步反应得到N,N’-二硝基-N,N ’-二(3-([1,2,3]-三唑并[4,5-c]呋咱-4,5-内盐-5-基)呋咱-4-基)二氨基甲烷(MNOTO),总收率为32.7％(以DAF计).用元素分析、核磁共振、红外光谱等进行了结构表征.用浓硝酸和醋酐作为硝化体系硝化N,N’-二(3-([1,2,3]-三唑并[4,5-c]呋咱-4,5-内盐-5-基)呋咱-4-基)二氨基甲烷(MAOTO),考察了反应温度、反应时间以及浓硝酸与醋酐摩尔比对反应收率的影响,硝化体系中硝酸和醋酐的最佳摩尔比为1.5∶1,反应温度15～20℃,反应时间为5h.     

2，2-双[4-（3，4-二氨基苯氧基）苯基]六氟丙烷的合成及表征

以六氟双酚A与5-氯-2-硝基苯胺为原料,在N,N-二甲基甲酰胺中发生缩合反应,再经Pd/C催化剂还原合成了一种新型的六氟四胺,其结构分别用元素分析、IR和 1HNMR进行了表征.这种新型四胺由于引入了六氟丙基和氧原子,可以用于合成溶解性能良好的聚苯并咪唑.