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1.
Akinori Nishio Amane Mochizuki Jun‐Ichi Sugiyama Kazuhiko Takeuchi Michihiko Asai Koichiro Yonetake Mitsuru Ueda 《Journal of polymer science. Part A, Polymer chemistry》2001,39(3):416-429
An ordered head‐to‐tail (HT) polyurethane was successfully prepared by the polyaddition reaction of p‐isocyanatobenzyl isocyanate with ethylene glycol with dibutyltin dilaurate as a catalyst. Furthermore, the HT regularity of polyurethane was improved to 83% with 1,1,3,3‐tetraphenyl‐1,3‐dichlorodistannoxane. The polymerization was conducted in N,N‐dimethylformamide at 30 °C with both monomers mixed at once. The microstructure of the polymer was investigated by 1H and 13C NMR spectroscopy, and the polymer obtained by the polyaddition reaction had the expected HT linkages. The constitutional regularity of the polymers influenced the thermal properties and crystallinity. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 416–429, 2001 相似文献
2.
A series of thermotropic liquid crystalline polyurethanes (LCPUs) were synthesized by the polyaddition reactions of 2,4‐toluene diisocyanate (2,4‐TDI) with 4,4′‐bis(6‐hydroxyhexoxy)biphenyl (BHHBP) and aliphatic diol. The intrinsic viscosities of the polymers were measured by Ubbelohde viscometer, and the chemical structure was confirmed by Fourier transform infrared spectroscopy (FT‐IR). The LCPUs were examined by differential scanning calorimetry (DSC), polarized optical microscopy (POM), wide angle X‐ray diffraction (WAXD), and thermogravimetric analysis (TGA). The intrinsic viscosities were 0.56–0.83 dl/g. According to the melting point (Tm) and the isotropic temperature (Ti) of the LCPUs, the temperature range of the liquid crystalline phase became wider with increased number of methylene spacers in the polyurethane. The LCPUs exhibited a nematic phase with a threaded texture and had a wide mesophase temperature range. The decomposition temperature of the LCPUs was >300°C. On WAXD, the LCPUs give a dispersing peak at 2θ ≈ 20°, and a strong diffraction peak at 2θ ≈ 25°. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
3.
A series of novel bismaleimides (BMIs) were prepared from maleic anhydride and polyurethane prepolymers based on MDI (4,4′-diphenylmethane diisocyanate) and polyether and polyester diols with various chain lengths. All the BMIs were characterized by IR, 1H-NMR, and elemental analysis. DSC studies indicated that the thermal polymerization of the BMIs could be carried out in the temperature range of 102–245°C, and that curing behavior was significantly affected by the molecular weight of the BMIs. The crosslinked BMI elastomers showed good mechanical properties and much better thermal stability than that of the traditional polyurethane elastomers. The glass transition temperatures, mechanical, and dynamic mechanical properties were dependent on the types of polyols used and the resultant crosslink densities due to various chain lengths of the BMIs. © 1994 John Wiley & Sons, Inc. 相似文献
4.
Osamu Haba Hiroshi Seino Kazutaka Aoki Kazuyuki Iguchi Mitsuru Ueda 《Journal of polymer science. Part A, Polymer chemistry》1998,36(13):2309-2314
The ordered (-aacdbbdc-) polymer was prepared by the direct polycondensation of a pair of symmetric monomers (XabX), 4,4′-(oxydi-p-phenylene)dibutanoic acid (XaaX) and 2-methoxyisophthalic acid (XbbX), with a nonsymmetric monomer (YcdY), 4-aminobenzhydrazide, using the condensing agent diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate ( 1 ). The polymerization was carried out by a one-pot procedure, that is, mixing the dicarboxylic acids, condensing agent 1 and triethylamine in NMP for 2 h at room temperature, followed by the addition of 4-aminobenzhydrazide. This polymerization proceeded smoothly, yielding the ordered polymer with an inherent viscosity of 0.34 dL g−1. The microstructure of the ordered polymer was confirmed by comparing the authentic ordered polymer in their 13C-NMR spectrum. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2309–2314, 1998 相似文献
5.
Yuki Ouchi Dr. Kazunori Sugiyasu Dr. Soichiro Ogi Akira Sato Prof. Dr. Masayuki Takeuchi 《化学:亚洲杂志》2012,7(1):75-84
We have recently reported a self‐threading polythiophene as a new family of insulated molecular wires. Herein, we focused on the structure–property relationships of the unique three‐dimensional architecture of the monomer. We have synthesized nine self‐threading bithiophene monomers that have cyclic side‐chains of different size and flexibility: i.e., 21‐, 22‐, 23‐, 24‐, 26‐, and 30‐membered rings composed of paraffinic, olefinic, or alkynic chains. To investigate their structure–property relationships, 1H NMR spectroscopy, UV absorption, and fluorescence spectroscopy measurements were conducted. We found that cyclic side‐chains define the movable range of the dihedral angle of the bithiophene backbone, thereby affecting its photophysical properties. Therefore, the ability to design a structure with atomic precision as described herein would lead to the fine‐tuning of the electronic properties of insulated molecular wires. 相似文献
6.
Yu-Chin Lai Edmond T. Quinn 《Journal of polymer science. Part A, Polymer chemistry》1995,33(11):1783-1793
UV-curable polyurethane prepolymers were prepared from the following components: iso-phorone diisocyanate, hydroxybutyl-terminated polysiloxane, and 2-hydroxyethyl meth-acrylate with diethylene glycol or neopentyl glycol added as an optional chain extender. These prepolymers, with hard segments of different structures, were characterized by high resolution NMR, FTIR, and gel permeation chromatography. Model oligomers were prepared to confirm the structures of the prepolymers. The structure–property relationship of cured prepolymers were determined. © 1995 John Wiley & Sons, Inc. 相似文献
7.
Olubummo Adekunle Florian Herbst Katharina Hackethal Wolfgang H. Binder 《Journal of polymer science. Part A, Polymer chemistry》2011,49(13):2931-2940
We present the synthesis of nonsymmetric α‐ω‐functionalized polyisobutylenes (PIBs) bearing different functional moieties on their chain ends. Thus, on one chain end either, a short tri‐ethylene oxide chain (TEO) or a phosphine oxide ligand is attached, whereas the other chain end is substituted by hydrogen bonding moieties (thymine/2,6‐diaminotriazine). The nonsymmetric PIBs were synthesized via living cationic polymerization using methyl‐styrene epoxide as initiator, followed by quenching reaction with 3‐bromopropyl‐benzene. Subsequent bromide/azide exchange and the use of the azide/alkyne click reaction allowed the synthesis of (a) (α)‐TEO‐(ω)‐thymine‐telechelic PIB ( 7a ), (b) (α)‐triethyleneoxide‐(ω)‐triazine telechelic PIB ( 7b ), and (c) (α)‐phosphinoxide‐(ω)‐thymine‐telechelic PIB ( 13 ) with molecular weights Mn ~ 4000 g mol?1 and low polydispersities (Mw/Mn = 1.3). The chemical identity of the final structures was proven by extensive 1H NMR investigations and matrix‐assisted laser desorption/ionization‐mass spectroscopy (MALDI). The presented method for the first time offers a simple and highly versatile approach toward supramolecular nonsymmetric α‐ω‐functionalized PIB. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
8.
Koji Takagi Eiki Kawagita Ryo Kouchi 《Journal of polymer science. Part A, Polymer chemistry》2014,52(15):2166-2174
The Grignard metathesis reaction of 2,5‐dibromo‐3‐(5′‐hexylpyridine‐2′‐yl)thiophene ( M1 ) with i‐PrMgCl afforded 5‐bromo‐2‐chloromagnesio‐3‐(5′‐hexylpyridine‐2′‐yl)thiophene ( GM1 ) in the 86% selectivity. The Kumada coupling polymerization by Ni(dppp)Cl2 gave poly M1 having the roughly controlled molecular weight between 6700 and 23,400. The characterization using the gel permeation chromatographic and matrix‐assisted laser desorption/ionization‐time of flight mass spectra indicated the diffusion of the nickel catalyst from the propagating end. Based on the GC and 1H NMR spectra, the head‐to‐tail content of poly M1 was calculated to be 89%. The regioselective Grignard metathesis reactions of 5,5′‐dibromo‐4‐(5″‐hexylpyridine‐2″‐yl)‐2,2′‐bithiophene ( M2 ) and 5,5′‐dibromo‐4‐(5″‐hexylpyrimidine‐2″‐yl)‐2,2′‐bithiophene ( M3 ) also occurred at the ortho‐position of the nitrogen heterocycle. The Kumada coupling polymerizations gave poly M2 and poly M3 having the head‐to‐tail content of 75% and 85%, respectively. The UV–vis spectra of polymers suggested that the polymer conformation becomes more planar in the order of poly M1 < poly M3 < poly M2 , which was investigated by the theoretical calculation of the model oligomers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2166–2174 相似文献
9.
Megan A. Cole Christopher N. Bowman 《Journal of polymer science. Part A, Polymer chemistry》2012,50(20):4325-4333
Three types of linear thiol‐functionalized siloxane oligomers and three types of ene‐functionalized oligomers were synthesized and subsequently photopolymerized. Within each type of thiol‐functionalized oligomer, the ratio of mercaptan repeat units to nonreactive phenyl repeat units was varied to manipulate both the crosslink density and the degree of secondary interactions through π–π stacking. Similarly, the repeat units of the three ene‐functionalized oligomers are composed of allyl‐functional monomers, benzene‐functional monomers, and octyl‐functional monomers in varying ratios of benzene:octyl but with a constant fraction of allyl moieties. The structural composition of the siloxane oligomers plays a pivotal role in the observed material properties of networks formed through thiol–ene photopolymerization. Networks with a high concentration of thiol functionalities exhibit higher rubbery moduli, ultimate strengths, and Young's moduli than networks with lower thiol concentrations. Moreover, the concentration of functionalities capable of participating in secondary interactions via hydrogen bonding or π–π stacking directly impacts the network glass transition temperature and elasticity. The combination of low crosslink density and high secondary interactions produces networks with the greatest toughness. Finally, the fraction of octyl repeats correlates with the hydrophobic nature of the network. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
10.
A series of perylene and naphthalene diimide‐containing random copolyurethanes with different ratios of perylene/naphthalene diimide content was synthesized and characterized. Copolymerization improved the solubility of these rigid aromatic diimides, and the copolymers were soluble in common organic solvents like chloroform, tetrahydrofuran, and so forth. The absorption spectra of perylene‐based copolymers showed a red‐shifted peak at a wavelength of 557 nm corresponding to J‐type aggregates. For naphthalene copolymers, the quenching of fluorescence at higher naphthalene incorporation suggested the presence of aggregates because of the extensive π‐π stacking of the aromatic core. FTIR spectroscopic analysis showed that the hydrogen bonding tendency of the polymer decreased with increase in perylene/naphthalene incorporation. The fluorescence spectra of the perylene polymers were exactly a mirror image of the absorption spectra. The fluorescence spectra of the naphthalene polymers at higher naphthalene incorporation showed a red‐shifted excimer like emission peak, which was assigned as static excimers based on their excitation spectra. These polymers could exhibit two types of secondary interaction modes, namely, hydrogen bonding (via urethane linkage) and π‐stacking (via aromatic perylene or naphthalene units) thus highlighting the importance of polymer design in inducing self‐organization at both low and high incorporation of the rigid bisimide moieties. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1224–1235, 2009 相似文献
11.
Synthesis and characterization of polyphenylenes with polypeptide and poly(ethylene glycol) side chains 下载免费PDF全文
Huseyin Akbulut Takeshi Endo Shuhei Yamada Yusuf Yagci 《Journal of polymer science. Part A, Polymer chemistry》2015,53(15):1785-1793
We report a novel approach for fabrication of multifunctional conjugated polymers, namely poly(p‐phenylene)s (PPPs) possessing polypeptide (poly‐l ‐lysine, PLL) and hydrophilic poly(ethylene glycol) (PEG) side chains. The approach is comprised of the combination of Suzuki coupling and in situ N‐carboxyanhydride (NCA) ring‐opening polymerization (ROP) processes. First, polypeptide macromonomer was prepared by ROP of the corresponding NCA precursor using (2,5‐dibromophenyl)methanamine as an initiator. Suzuki coupling reaction of the obtained polypeptide and PEG macromonomers both having dibromobenzene end functionality using 1,4‐benzenediboronic acid as the coupling partner in the presence of palladium catalyst gave the desired polymer. A different sequence of the same procedure was also employed to yield polymer with essentially identical structure. In the reverse sequence mode, low molar mass monomer (2,5‐dibromophenyl)methanamine, and PEG macromonomer were coupled with 1,4‐benzenediboronic acid in a similar way followed by ROP of the L‐Lysine NCA precursor through the primary amino groups of the resulting polyphenylene. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1785–1793 相似文献
12.
Dr. Malika Makhlouf Brahmi Dr. Cyril Portmann Danilo D'Ambrosio Dr. Tom M. Woods Damiano Banfi Patrick Reichenbach Laeticia Da Silva Emilie Baudat Dr. Gerardo Turcatti Prof. Dr. Joachim Lingner Prof. Dr. Karl Gademann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(14):4596-4601
By using the Telospot assay, 27 different extracts of cyanobacteria were evaluated for telomerase inhibition. All extracts showed varying, but significant activity. We selected Microcystis aeruguinosa PCC 7806 to identify the active compound and a bioassay guided fractionation led us to isolate mixtures of sulfoquinovosyl diacylglycerols (SQDGs), which were identified by 2D NMR and MS/MS experiments. Pure SQDG derivatives were then synthesized. The IC50 values of pure synthetic sulfoquinovosyl dipalmitoylglycerol and the monopalmitoylated derivative against telomerase were determined to be 17 and 40 μM , respectively. A structure–activity relationship study allowed the identification of compounds with modified lipophilic acyl groups that display improved activity. 相似文献
13.
Dr. Sangen Zhao Pifu Gong Dr. Siyang Luo Dr. Lei Bai Prof. Zheshuai Lin Yuanyuan Tang Yuelan Zhou Prof. Maochun Hong Prof. Junhua Luo 《Angewandte Chemie (International ed. in English)》2015,54(14):4217-4221
A nonlinear optical phosphate Ba5P6O20 was rationally developed by a tailored synthetic approach based on the use of flexible [P3O10]5? units. The phosphate exhibits a very short absorption edge of λ=167 nm, which is among the shortest known in phase‐matchable phosphates. First‐principles electronic structure analysis elucidated the origin of the changes in the optical properties, and specifically in the absorption edge, of the material. Such a tailored synthetic approach provides a new opportunity to design nonlinear optical materials with short absorption edges. 相似文献
14.
《化学:亚洲杂志》2017,12(5):615-620
Controllable synthesis of coordination polymer (CP) isomers and revealing their structure–property relationships remain enormous challenges. Three new supramolecular isomers have been synthesized by tuning the poly(ethylene glycol) (PEG) content in the feed. These supramolecular isomers have the same framework formula of [Cu2I2(tppe)] and different architectures from the classical 2D stacking framework to a 3D entangled system with the coexistence of interpenetration and polycatenation, and a 3D topological framework. Interestingly, these CPs could be utilized for capturing iodine molecules. According to multiple complementary experiments and crystallographic analyses, iodine capture is mainly based on halogen‐bond interactions in the inorganic {Cu2I2} building blocks of the framework. The present study describes a structure–property relationship in supramolecular isomerism with distinct topological structures. 相似文献
15.
A Systematic Study of Peripherally Multiple Aromatic Ester‐Functionalized Poly(benzyl ether) Dendrons for the Fabrication of Organogels: Structure–Property Relationships and Thixotropic Property 下载免费PDF全文
Dr. Yu Feng Zhi‐Xiong Liu Hui Chen Zhi‐Chao Yan Yan‐Mei He Prof. Dr. Chen‐Yang Liu Prof. Dr. Qing‐Hua Fan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(23):7069-7082
A new class of peripherally multiple aromatic ester‐functionalized poly(benzyl ether) dendrons and/or dendrimers with different focal point substituents, surface groups, interior structures, as well as different generations have been synthesized and their structure–property relationships with respect to their gelation ability have been investigated systematically. Most of these dendrons are able to gel organic solvents over a wide polarity range. Evident dendritic effects were observed not only in gelation capability but also in thermotropic, morphological, and rheological characterizations. It was disclosed that subtle changes in peripheral ester functionalities and interior dendritic structures affected the gelation behavior of the dendrons significantly. Among all the dendrons studied, the second‐ and third‐generation dendrons G0G2‐Me and G0G3‐Me with dimethyl isophthalates (DMIP) as peripheral groups exhibited the best capability in gelation, and stable gels were formed in more than 22 aromatic and polar organic solvents. The lowest critical gelation concentration (CGC) reached 2.0 mg mL?1, indicating that approximately 1.35×104 solvent molecules could be entrapped by one dendritic molecule. Further study on driving forces in gel formation was carried out by using a combination of single‐crystal/powder X‐ray diffraction (XRD) analysis and concentration‐dependent (CD)/temperature‐dependent (TD) 1H NMR spectroscopy. The results obtained from these experiments revealed that the multiple π–π stacking of extended π‐systems due to the peripheral DMIP rings, cooperatively assisted by non‐conventional hydrogen‐bonding, is the key contributor in the formation of the highly ordered supramolecular and fibrillar network. In addition, these dendritic organogels exhibited unexpected thixotropic‐responsive properties, which make them promising candidates with potential applications in the field of intelligent soft materials. 相似文献
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17.
Richard J. Mandle Edward J. Davis Craig T. Archbold Constantin C. A. Voll Jessica L. Andrews Stephen J. Cowling John W. Goodby 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8158-8167
The nematic twist–bend phase (NTB) was, until recently, only observed for polar mesogenic dimers, trimers or bent‐core compounds. In this article, we report a comprehensive study on novel apolar materials that also exhibit NTB phases. The NTB phase was observed for materials containing phenyl, cyclohexyl or bicyclooctyl rings in their rigid‐core units. However, for materials with long (>C7) terminal chains or mesogenic core units comprising three ring units, the NTB phase was not observed and instead the materials exhibited smectic phases. One compound was found to exhibit a transition from the NTB phase to an anticlinic smectic C phase; this is the first example of this polymorphism. Incorporation of lateral substitution with respect to the central core unit led to reductions in transition temperatures; however, the NTB phase was still found to occur. Conversely, utilising branched terminal groups rendered the materials non‐mesogenic. Overall, it appears that it is the gross molecular topology that drives the incidence of the NTB phase rather than simple dipolar considerations. Furthermore, dimers lacking any polar groups, which were prepared to test this hypothesis, were found to be non mesogenic, indicating that at the extremes of polarity these effects can dominate over topology. 相似文献
18.
Ming Liu Sandrine Peyrat Nicolas Illy Véronique Wintgens Blandine Brissault Jacques Penelle Valessa Barbier 《Journal of polymer science. Part A, Polymer chemistry》2014,52(16):2337-2345
We report the synthesis and ion‐binding properties of four poly(crown‐ethers) displaying either one or two crown‐ethers (15‐crown‐5 or 18‐crown‐6) on every third carbon alongside the backbone. The polymers were synthesized by living anionic ring‐opening polymerization of disubstituted cyclopropane‐1,1‐dicarboxylates monomers. Cation binding of the polychelating polymers and corresponding monomers to Na+ and K+ was evaluated by picrate extraction and isothermal calorimetry titration. This novel family of poly(crown‐ethers) demonstrated excellent initial binding of the alkali ions to the polymers, with a higher selectivity for potassium. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2337–2345 相似文献
19.
Shuai Liu Xiaomeng Liu Sangen Zhao Youchao Liu Lina Li Qingran Ding Yanqiang Li Zheshuai Lin Junhua Luo Maochun Hong 《Angewandte Chemie (International ed. in English)》2020,59(24):9414-9417
Birefringent materials, which can modulate the polarization of light, are almost exclusively limited to oxides. Peroxides have long been overlooked as birefringent materials, because they are usually not stable in air. Now, the first peroxide birefringent material Rb2VO(O2)2F is reported, the single crystals of which keep transparency after being exposed in the air for two weeks. Interestingly, Rb2VO(O2)2F does not feature an optimal anisotropic structure, but its birefringence (Δn=0.189 at 546 nm) exceeds those of the majority of oxides. According to the first‐principles calculations, this exceptional birefringence should be attributed to the strong electronic interactions between localized π orbital of O22? anions and V5+ 3d orbitals, which may be also favorable to the stability in the air for Rb2VO(O2)2F. These findings distinguish peroxides as a brand‐new class of birefringent materials that may possess birefringence superior to the traditional oxides. 相似文献
20.
Edwin W. Y. Wong Jeffrey S. Ovens Daniel B. Leznoff 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(22):6781-6787
A series of new substituted 1,3‐bis(2‐pyridylimino)isoindolines—1,3‐bis(2‐pyridylimino)‐5,6‐bis(2,6‐diisopropylphenoxy)isoindoline ( 2 b ), 1,3‐bis(2‐pyridylimino)‐5,6‐bis(4‐tert‐butylphenyl)isoindoline ( 2 c ), and 1,3‐bis(2‐pyridylimino)‐5‐tert‐butylisoindoline ( 2 d )—were synthesized and structurally characterized by single‐crystal X‐ray diffraction. The birefringence (Δn) of the crystals of unsubstituted 1,3‐bis(2‐pyridylimino)isoindoline ( 2 a ), 2 b , 2 c , and 2 d were measured and found to vary greatly, with Δn values of 0.0654(3), 0.0629(17), 0.588(10), 0.701(12), respectively. A structure–property relationship for the birefringence values of 2 a – 2 d was outlined and indicated that the anisotropy of the polarizability of the molecules plays a crucial role in the birefringence of the crystals. The greatest birefringence values are achieved when the molecules are oriented in a face‐to‐face configuration intermolecularly, and along the crystallographic face being measured. 相似文献