Synthesis and characterization of poly(methylphenylsilylene)–poly(ethylene oxide) and poly(methylphenylsilylene)–polyisoprene multiblock copolymers

Multiblock copolymers were synthesized through condensation reactions of end‐groups of α,ω‐dichloro‐poly(methylphenylsilylene) with hydroxyl end‐groups of poly(ethylene glycol) or the chain‐ends of ‘living’ polyisoprenyl disodium. Optimum conditions have been sought through kinetic studies and by investigation of model reactions. The overall molecular weight distribution of poly(methylphenylsilylene)‐block‐poly(ethylene oxide) is characterized in terms of Flory's theory of condensation reactions, while the limiting step in the reaction is tentatively attributed to the formation of aggregates. © 2001 Society of Chemical Industry     

Synthesis and characterization of poly(butylene terephthalate)‐co‐poly(butylene succinate)‐block‐poly(ethylene glycol) segmented block copolymers

Poly(butylene terephthalate)‐co‐poly(butylene succinate)‐block‐poly(ethylene glycol) segmented random copolymers, with poly(butylene succinate) (PBS) molar fraction (M_PBS) varying from 10 to 60 %, were synthesized through a melt polycondensation process and characterized by means of GPC, NMR, DSC and mechanical testing. The number‐average relative molecular mass of the copolymers was higher than 4 × 10⁴ g mol^?1 with polydispersity below 1.9. Sequence distribution analysis on the two types of hard segments by means of ¹H NMR revealed that the number‐average sequence length of PBT decreased from 2.80 to 1.23, while that of PBS increased from 1.27 to 4.76 with increasing M_PBS. The random distribution of hard segments was also justified because of the degree of randomness around 1.0. Micro‐phase separation structure was verified for the appearance of two glass transition temperatures and two melting points, respectively, in DSC thermograms of most samples. The crystallinity of hard segments changed with the crystallizability controlled by the average sequence length and reached the minimum value at an M_PBS of about 50–60 mol%. The results can also be ascribed to the co‐crystallization between two structurally analogous hard segments. Mechanical testing results demonstrated that incorporating a certain amount of PBS moieties (less than 30 mol%), at the expense of a minute depression of the elastic modulus, that higher relative elongation and more flexibility of polymer chain could be expected. Maximum equilibrium water absorption and faster degradation rates were observed on samples with higher M_PBS values and lower crystallinity of hard segments were better hydrophilicity of the polymer chain, through in vitro degradation experiments. Copyright © 2003 Society of Chemical Industry     

Preparation of new poly(amide–imide)s with chiral architectures via direct polyamidation reaction

N‐trimellitylimido‐L ‐methionine ( 3 ) was prepared by reaction of trimellitic anhydride ( 1 ) with ‐L ‐methionine ( 2 ) in acetic acid solution at refluxing temperature. This diacid was reacted with thionyl chloride, and N‐trimellitylimido‐L ‐methionine diacid chloride ( 4 ) was obtained in quantitative yield. The resulting diacid chloride was reacted with p‐aminobenzoic acid in dry acetone and bis(p‐aminobenzoic acid)‐N‐trimellitylimido‐L ‐methionine ( 5 ) was obtained as a novel optically active amide–imide diacid monomer in high yield. The direct polycondensation of amide–imide diacid monomer 5 with several aromatic diamines was carried out with tosyl chloride (TsCl)/pyridine (Py)/dimetheylformamide (DMF) system. The resulting thermally stable poly(amide–imide)s (PAIs) were obtained in good yields and inherent viscosities ranging between 0.24 and 0.46 dL g^?1 and were characterized with FTIR, ¹H NMR, CHN, and TGA techniques. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1248–1254, 2007     

聚(四甲基对硅亚苯基-二甲基)硅氧烷共聚物的制备及其热性质

以对二溴苯为起始原料,在超声辐照下制备得到对二溴苯双格氏试剂,然后与二甲基氢氯硅烷制备得到1,4-双(二甲基硅基)苯)(BDSB)。以B(C6F5)3为催化剂,BDSB与二甲基二甲氧基硅烷缩聚制备得到聚(四甲基对硅亚苯基-二甲基)硅氧烷共聚物(PTMPS-DMS),并对催化剂浓度、反应温度对反应速率的影响进行了研究。29SiNMR表明产物不是严格交替共聚物,具有38%～49%的嵌段结构。PTMPS-DMS的Tg=-56.2℃,起始降解温度氮气、空气中分别为334℃、345℃。在氮气中PTMPS-DMS出现一步热失重,最大热失重温度是529℃,在空气中则分别在539℃、559℃、662℃出现多步热失重。     

Preparation of amorphous poly(ethylene terephthalate) from U‐polymer via a copolymerization process

U‐Polymer, a kind of polyarylate, was synthesized by interfacial polycondensation method with terephthaloyl chloride (TPC), isophthaloyl chloride (IPC), and bisphenol A (BPA) as raw materials. The structure of the U‐Polymer was characterized by IR and ¹H–NMR spectra. Then, an amorphous poly(ethylene terephthalate) (APET) was prepared with the introduction of the U‐Polymer to the PET sequence to improve thermal and mechanical behaviors of PET via the polymerization process. The structure and property of the APET were characterized by DSC and DMA. The results showed that the APET exhibits amorphism, transparency, higher glass‐transition temperature (T_g), and higher storage modulus than that of PET. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1653–1657, 2001     

电纺制备苯乙烯甲基丙烯酸共聚物单轴定向纳米纤维

采用无皂乳液法合成了带有羧基的苯乙烯-甲基丙烯酸共聚物,并利用静电纺丝技术,得到了不同形貌的直径约为800nm的纳米纤维。同时通过对传统的平面导体收集装置的改进,得到了大面积、单轴定向的功能纳米纤维。     

Mesomorphic polyblends of poly(p-phenylene terephthalamide) and poly(4,4′-terephthanilide adipamide)

A simultaneous dissolution of two lyotropic polyamides, poly(p-phenylene terephthalamide) (PPTA) and poly(4,4′-terephthanilidc adipamide) (PTAd), in a concentrated H₂SO₄ (1 to 1.5% wt) produced an isotropic single phase solution. The crystallinity of PPTA/PTAd blends confirmed formation of a mesomorphic polyblend to the molecular level. With increasing concentration, solutions of these PPTA/PTAd blends in 100% H₂SO₄ showed a sequential phase change typical of a single lyotropic polymer. Further, the ternary solution exhibited a wider biphase range than both binary solutions of PPTA/100% H₂SO₄ and PTAd/100% H₂SO₄. Dry-jet wet spinning of anisetropic solution of this ternary composition with a PTAd weight fraction less than 0.5 enabled us to obtain PPTA/PTAd blend fibers. Including a PTAd weight fraction of 0.1-0.15 reduced both the orientation angle and fibrillation. The particular blend fiber with a PTAd weight fraction of 0.15 exhibited a synergistic effect on the mechanical properties.     

Preparation and characterization of poly(p-phenylenediamine-co-xylidine)

p-Phenylenediamine (PPDA) homopolymer and its copolymers with 2,3-xylidine (XY) were synthesized by oxidative polymerization using potassium persulfate as an oxidant in HCl medium at room temperature. The yield, intrinsic viscosity, and solubility of the polymers were significantly dependent on the monomer ratio. The resulting polymers were characterized by Fourier transform IR spectroscopy, ¹H-NMR spectroscopy, wide-angle X-ray diffraction, and thermogravimetry methods. The results showed that the number-average degree of polymerization of the PPDA homopolymer was 33 and the actual content of XY units in the copolymer was slightly higher than the feed XY unit content. The polymers were substantially amorphous and showed the strongest diffraction at a Bragg angle of 3°. The polymers exhibited a thermal decomposition temperature higher than 436°C, the maximum weight-loss rate was slower than 4%/min, and the char yield was larger than 24 wt % at 600°C in nitrogen. The activation energy of thermal decomposition for the polymers increased from 19 to 25 kJ/mol with increasing XY unit contents from 0 to 10 mol %. The polymers showed higher thermostability but lower activation energy of decomposition in nitrogen than in air. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3107–3116, 2001     

Morphological studies of LC polymer networks prepared by photopolymerization of (LC monomer/LC) blends

The morphology of LC polymer networks prepared by photopolymerization of (LC monomer/LC) blends containing photoinitiator and crosslinker was investigated. For the blends of 4-acryloyloxyhexyloxy-4′-cyanobiphenyl and 4-hexyloxy-4′-cyanobiphenyl, which had the same mesogen, orientation order of LC textures was memorized by photopolymerization, while any structure of LC polymer networks was not observed under an optical microscope because the networks did not phase separate from the low molecular weight LC. However, specific anisotropic phase-separated structures of LC polymer networks were observed for the blends of 4-acryloxloxyhexyloxy-4′-cyanobiphenyl and 4-hexyloxybenzoic acid, which had dissimilar mesogens, on condition that photopolymerization was carried out under the LC phase. If photopolymerization was performed under the isotropic phase conditions, polygonal or continuous phase-separated structures of LC polymer networks were observed for the dissimilar mesogenic blend. These morphologies were strongly dependent on the phase diagrams of (LC monomer/LC) blends and (the corresponding LC polymer/LC) blends. It has been found that the ordering field of LC molecules can give LC polymer networks anisotropic morphologies, which have the long range as the same length scale of LC textures.     

Oligomeric poly(ether‐imide)s bearing ortho trifluoromethyl groups: Solubility,thermal studies,and optical properties

In the development of processable high‐temperature materials, six new aromatic poly(imide)s based on diamines containing ortho trifluoromethyl groups, ether linkages and R,R‐methylenes moieties (R = Me or Ph) and previously reported dianhydrides have been synthesized vía polycondensation reactions. All polymers were obtained with good yields, were soluble in a variety of polar aprotic solvents, and exhibited inherent viscosity (η_inh) values between 0.15 and 0.20 dL g^?1, which is indicative of low molecular‐weight species. Preliminary studies of their physical properties were carried out. The new materials were transparent in the visible region and they exhibited thermal decomposition temperatures ranging from 475 to 545 °C and glass‐transition temperatures varying from 288 to 304 °C. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46613.     

Facile synthesis and micellization of biodegradable poly(decamethylene succinate)‐graft‐poly(ethylene glycol)

In this article, we report the facile one‐pot synthesis of poly(decamethylene succinate) (PDS) with multiple hydroxyl groups by direct polycondensation with malic acid (MA) as the functional monomer and dysprosium triflate as the chemoselective catalyst at 80°C. The secondary hydroxyl groups of malic units were inactive during the polycondensation process. The density of hydroxyl groups of the copolymer could be well‐controlled by the molar ratio of succinic acid and MA in the feed. These hydroxylated PDSs were grafted by poly(ethylene glycol) (PEG) through a simple esterification reaction; this resulted in amphiphilic PDS‐g‐PEG copolymers, which could undergo micellization in aqueous media to form nanosized aggregates with diverse morphologies and diameters. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013.     

Fumed silica filled poly(dimethylsiloxane-urea) segmented copolymers: Preparation and properties

Novel fumed silica filled thermoplastic poly(dimethylsiloxane-urea) (TPSU) segmented copolymers were synthesized and characterized. TPSU copolymers were prepared from a cycloaliphatic diisocyanate, aminopropyl terminated PDMS oligomers with number average molecular weights of 3,200, 10,800 and 31,500 g/mol and 2-methyl-1,5-diaminopentane chain extender. Two different types of fumed silica HDK H2000 (hydrophobic) and HDK N20 (hydrophilic) were utilized and incorporated into silicone-urea copolymers in amounts of 1-60% by weight. Influence of the silica type (hydrophilic versus hydrophobic), amount of silica loading and the PDMS soft segment molecular weight on the morphology, tensile properties and modulus-temperature behavior of the nanocomposites were determined. Major observations of this study were: (i) under the blending conditions used, incorporation of silica does not seem to interfere significantly with the hydrogen bonding between urea groups, (ii) incorporation of silica does not affect the glass transition temperature of PDMS, (iii) incorporation of silica influences the tensile and thermomechanical properties of silicone-urea segmented copolymers significantly, (iv) average molecular weight of the PDMS soft segment in the silicone-urea copolymer plays a critical role on the improvement of the tensile properties of the fumed silica/TPSU composites.     

Preparation and characterization of poly(ethylene/tetramethylene terephthalate) copolyesters

Random copolyesters were prepared from dimethyl terephthalate (DMT), ethylene glycol (EG) and butane 1,4-diol (BD) by melt-polycondensation techniques, using varying amounts of EG and BD. Compositions have been established by ¹H n.m.r. spectroscopy. Intrinsic viscosity and number average molecular weight ($\text{M}\text{?}{}_{\mathrm{n}}$) were measured. Thermal properties have been studied by differential thermal analysis. Melting and crystallization temperatures and thermodynamic parameters are discussed in terms of structural differences, particularly the effect of composition and chain flexibility. The degree of crystallinity from differential thermal analysis, i.r. and wide angle X-ray scattering (WAXS) are discussed.     

Preparation of novel pyridine‐based,thermally stable poly(ether imide)s

Two aromatic, pyridine‐based ether diamines were prepared by the nucleophilic aromatic substitution reaction of 4‐aminophenol and 5‐amino‐1‐naphthol with 2,6‐dichloropyridine in N‐methyl‐2‐pyrrolidone as a solvent. Polycondensation reactions of the obtained diamines with pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and hexafluoroisopropylidene diphthalic anhydride resulted in six pyridine‐based, thermally stable poly(ether imide)s. The prepared monomers and polymers were characterized by common spectroscopic methods. The physical and thermal properties of the polymers, including the thermal behavior, thermal stability, solubility, and solution viscosity, were studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 22–26, 2004     

Preparation and properties of electroconductive acrylonitrile grafted poly(vinyl alcohol) modified nembrane

PVA-g-AN was prepared, the yield and the graft efficiency were determined. A PVA-g-AN metal chelated film was then prepared by mixing and soaking methods, separately. After treatment with NaBH₄ aqueous solution or H₂S gas, the electrical and photoconductive properties were investigated. In order to increase the adsorption amount for metal ion in the soaking method, the amidoxime group was introduced into the PVA-g-AN film in various conditions. The proposed structures of the metal chelated PVA-g-AN films were also studied.     

Thermally stable and organosoluble cardo binaphthylene based poly(amide imide)s and poly(ester imide)s

A new imide‐containing dicarboxylic acid based on a twisted binaphthylene unit, 2,2′‐bis(N‐trimellitoyl)‐1,1′‐binaphthyl (1), was synthesized from 1,1′‐binaphthyl‐2,2′‐diamine and trimellitic anhydride in glacial acetic acid. The structure of compound 1 was fully characterized with spectroscopic methods and elemental analysis. Series of thermally stable and organosoluble poly(amide imide)s (4a–4d) and poly(ester imide)s (5a–5d) with similar backbones were prepared by the triphenyl phosphite and diphenylchlorophosphate activated direct polycondensation of diimide dicarboxylic acid 1 with various aromatic diamines and diols, respectively. With due attention to the structural similarity of the resulting poly(amide imide)s and poly(ester imide)s, most of the differences between these two block copolyimides could be easily attributed to the presence of alternate amide or ester linkages accompanied by imide groups in the polymer backbone. The ultraviolet maximum wavelength values of the yellowish polymers were determined from their ultraviolet spectra. The crystallinity of these copolyimides was estimated by means of wide‐angle X‐ray diffraction, and the resultant polymers exhibited a nearly amorphous nature, except for the polymers derived from benzidine and 4,4′‐binaphthol. The poly(amide imide)s exhibited excellent solubility in a variety of highly polar aprotic solvents, whereas the poly(ester imide)s showed good solubility in less polar solvents. According to differential scanning calorimetry analyses, polymers 4a–4d and 5a–5d had glass‐transition temperatures between 331 and 357°C and between 318 and 342°C, respectively. The thermal behaviors of the obtained polymers were characterized by thermogravimetric analysis, and the 10% weight loss temperatures of the poly(amide imide)s and poly(ester imide)s were between 579 and 604°C and between 566 and 577°C in nitrogen, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3203–3211, 2006     

Crosslinkable fully aromatic poly(aryl ether ketone)s bearing macrocycle of aryl ether ketone

A novel bisphenol monomer, (3-methoxy)phenylhydroquinone, was synthesized via a three-step synthetic procedure. The cyclization of the bisphenol monomer and 4,4-difluorobenzophenone was carried out under pseudo high dilution condition. Two types of fully aromatic poly(aryl ether ketone)s were prepared by copolymerization of macrocycle of aryl ether ketone (MACEK) containing hydroxyphenyl, 4,4′-(hexafluoroisopropylidene)diphenol (HFBPA), and 4,4-difluorobenzophenone. The copolymers have high molecular mass, good solubility and high glass transition temperatures. The copolymers are crosslinkable in the presence of basic initiator and the glass transition temperatures of the copolymers increased greatly after the curing. These cured copolymers exhibit excellent thermal stability, and the 5% weight loss temperatures are around 500 °C in nitrogen.     

Preparation and properties of new thermally stable poly(ether imide amide)s

2,6‐Bis(4‐aminophenoxy)pyridine was prepared via reaction of 4‐aminophenol with 2,6‐dichloropyridine in the presence of potassium carbonate. Reaction of the diamine with two mol of trimellitic anhydride afforded a diacid with preformed imide structures. Poly(ether imide amide)s were prepared by polycondensation reactions of the diacid with different diamines in the presence of triphenyl phosphite. All the monomers and polymers were fully characterized and the physical properties of the polymers including solution viscosity, thermal stability, thermal behavior and solubility were studied. Thermal analysis data showed the polymers to have high thermal stability. Copyright © 2004 Society of Chemical Industry     

Preparation of poly(acrylonitrile-butyl acrylate) gel electrolyte for lithium-ion batteries

Poly(acrylonitrile-butyl acrylate) gel polymer electrolyte was prepared for lithium ion batteries. The preparation started with synthesis of poly(acrylonitrile-butyl acrylate) by radical emulsion polymerization, followed by phase inversion to produce microporous membrane. Then, the microporous gel polymer electrolytes (MGPEs) was prepared with the microporous membrane and LiPF₆ in ethylene carbonate/diethyl carbonate. The dry microporous membrane showed a fracture strength as high as 18.98 MPa. As-prepared gel polymer electrolytes presented ionic conductivity in excess of 3.0 × 10⁻³ S cm⁻¹ at ambient temperature and a decomposition voltage over 6.6 V. The results showed that the as-prepared gel polymer electrolytes were promising materials for Li-ion batteries.     

Preparation and characterization of highly swelling smart grafted polymer networks of poly(vinyl alcohol) and poly(acrylic acid–co–acrylamide)

Smart grafted polymer networks comprising random copolymer of poly(acrylic acid‐co‐acrylamide) and polyvinyl alcohol and exhibiting extraordinary water imbibtion property were prepared by free radical polymerization method and characterized by Fourier Transform infrared spectroscopy, Ultra Violet spectroscopy, Environmental Scanning Electron Microscopy, Thermogravimetric Analysis, Differential Scanning Calorimetry, and X–ray Diffraction. The mesh size (ξ) and chain flexibility factor (α) of interpenetrating polymer networks were calculated for various grafted polymer network compositions and correlated with their water sorption capacity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 84–95, 2006