共查询到20条相似文献,搜索用时 31 毫秒
1.
Robert D. Murphy Elena Bobbi Fernando C. S. de Oliveira Sally‐Ann Cryan Andreas Heise 《Journal of polymer science. Part A, Polymer chemistry》2019,57(11):1209-1215
This work reports the synthesis of a new difunctional N‐carboxyanhydride (NCA) monomer, namely diaminopimelic acid (DAP), and its use in the one‐pot preparation of an organogelating copolypeptide. The organogel is formed in situ through ring‐opening polymerization (ROP) of DAP NCA from helical poly(ε‐carbobenzyloxy‐L‐lysine) (PZLL) blocks in a mixture of dimethylformamide/chloroform. Gelation occurs by immobilizing the solvent through core crosslinking and is stabilized through physical intermolecular conformations. After removal of the carbobenzyloxy (cbz or Z) protecting groups, the network remains intact in exceedingly high aqueous concentrations (99.5%). FTIR is used to characterize the secondary structure, revealing the conformational arrangements that contributed to these stabilized gel networks with their relative mechanical properties determined via real‐time rheological assays. DAP core crosslink of the random coil forming polypeptoid poly(sarcosine) (PSar) is also resulting in networks but is devoid of any stabilized physical interactions, thus yielding significantly weaker gels as a result. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 相似文献
2.
A new class of linear unsaturated polyphosphate esters based on divanillylidene cyclohexanone possessing liquid crystalline‐cum‐photocrosslinkable properties have been synthesized from 2,6‐bis[n‐hydroxyalkyloxy(vanillylidene)]cyclohexanone [n = 6,8,10] with various alkyl/aryl phosphorodichloridates in chloroform at ambient temperature. The resultant polymers were characterized by intrinsic viscosity, FT‐IR, 1H, 13C, and 31P‐NMR spectroscopy. All the polymers showed anisotropic behavior under hot stage optical polarized microscope (HOPM). The liquid crystalline textures of the polymers became more transparent with increasing spacer length. The thermal behavior of the polymers was studied by thermogravimetric analysis and differential scanning calorimetry. The Tg, Tm, and Ti of the polymers decreased with increasing flexible methylene chain. The photocrosslinking property of the polymer was investigated by UV light/UV spectroscopy; the crosslinking proceeds via 2π‐2π cycloaddition reactions of the divanillylidene exocyclic double bond of the polymer backbone. The pendant alkyloxy containing polymers show faster crosslinking than the pendant phenyloxy containing polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5215–5226, 2004 相似文献
3.
Lijun Fan Hou Chen Zhihai Hao Zhi Tan 《Journal of polymer science. Part A, Polymer chemistry》2013,51(2):457-462
Cellulose produced from cotton fibers was used as substrate for synthesis of oil‐absorbing materials by single electron transfer‐living radical polymerization. The cellulose macroinitiator was prepared by esterification of hydroxyl group with 2‐bromoisobutyryl bromide (BiBB), followed by grafting with butyl methacrylate (BMA) and pentaerythritol triacrylate (PETA) to render a three‐dimensional architecture. The polymerization was catalyzed by Cu(0) powder/hexamethylenetetramine (HMTA) and performed in N,N‐dimethylformamide (DMF). Effects of cellulose, catalyst, reaction temperature, and time were investigated in detail. The maximum oil absorption to chloroform and toluene could reach 29.0 and 15.4 g·g?1, respectively. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
4.
Kazukiyo Nagai Lora G. Toy Benny D. Freeman Masahiro Teraguchi Giseop Kwak Toshio Masuda Ingo Pinnau 《Journal of Polymer Science.Polymer Physics》2002,40(19):2228-2236
The gas permeability and n‐butane solubility in glassy poly(1‐trimethylgermyl‐1‐propyne) (PTMGP) are reported. As synthesized, the PTMGP product contains two fractions: (1) one that is insoluble in toluene and soluble only in carbon disulfide (the toluene‐insoluble polymer) and (2) one that is soluble in both toluene and carbon disulfide (the toluene‐soluble polymer). In as‐cast films, the gas permeability and n‐butane solubility are higher in films prepared from the toluene‐soluble polymer (particularly in those films cast from toluene) than in films prepared from the toluene‐insoluble polymer and increase to a maximum in both fractions after methanol conditioning. For example, in as‐cast films prepared from carbon disulfide, the oxygen permeability at 35 °C is 330 × 10?10 cm3 (STP) cm/(cm2 s cmHg) for the toluene‐soluble polymer and 73 × 10?10 cm3 (STP) cm/(cm2 s cmHg) for the toluene‐insoluble polymer. After these films are conditioned in methanol, the oxygen permeability increases to 5200 × 10?10 cm3 (STP) cm/(cm2 s cmHg) for the toluene‐soluble polymer and 6200 × 10?10 cm3 (STP) cm/(cm2 s cmHg) for the toluene‐insoluble polymer. The rankings of the fractional free volume and nonequilibrium excess free volume in the various PTMGP films are consistent with the measured gas permeability and n‐butane solubility values. Methanol conditioning increases gas permeability and n‐butane solubility of as‐cast PTMGP films, regardless of the polymer fraction type and casting solvent used, and minimizes the permeability and solubility differences between the various films (i.e., the permeability and solubility values of all conditioned PTMGP films are similar). © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2228–2236, 2002 相似文献
5.
K. P. O. Mahesh M. Sivakumar Y. Yamamoto Y. Tsujita H. Yoshimizu S. Okamoto 《Journal of Polymer Science.Polymer Physics》2004,42(18):3439-3446
A crystalline δ form of a syndiotactic polystyrene (sPS) membrane was prepared from a solution of sPS (1 wt %) and p‐chlorotoluene (p‐CT) by a solution‐casting method. The mesophase (δ empty form) of sPS was obtained by the extraction of the guest solvent from the δ form of sPS by a stepwise solvent‐extraction method. The sPS/p‐CT mesophase membrane [p‐CT (A‐M)] was used for the sorption of 1 mol % p‐CT for different times and for the sorption of different concentrations of p‐CT, chlorobenzene (CB), p‐xylene (p‐X), toluene, and chloroform for 48 h. The presence of solvents in the sPS membrane was confirmed by IR analysis. A thermal study revealed that the sorption amount of 1 mol % p‐CT increased with increasing immersion time, and the sorption amounts of different solvents increased with increasing solvent concentration. Differential scanning calorimetry results showed that the desorption peak temperature increased as the amount of the solvent increased in the clathrated sPS membrane. Wide‐angle X‐ray diffraction results showed that 2θ at 8.25° was slightly shifted toward 8°, and there was no change in the peak position at 10° for p‐CT (A‐M), which was immersed in different solvents (1 mol %); however, the intensity of 2θ at 10° was not similar for all the samples. Among the solvents used for the sorption studies at 1 mol %, p‐CT (A‐M) could sorb more p‐CT and CB than p‐X, toluene, and chloroform. The solvent sorption isotherm was the Langmuir sorption mechanism. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3439–3446, 2004 相似文献
6.
Ergang Wang Chun Li Junbiao Peng Yong Cao 《Journal of polymer science. Part A, Polymer chemistry》2007,45(21):4941-4949
A novel blue‐emitting polymer based on 3,6‐silafluorene and 2,7‐silafluorene was synthesized via the Suzuki polycondensation. The resulting polymers are readily soluble in common organic solvents, such as toluene, xylene, THF, and chloroform. The thermal, electrochemical, photophysical, and electroluminescence properties of the resulting polymers were investigated. The device fabricated from the copolymer with a configuration of ITO/PEDOT:PSS/PVK/polymer/Ba/Al exhibited an external quantum efficiency of 1.95%, a luminous efficiency of 1.69 cd A?1 and a maximal brightness of 6000 cd m?2. It has been found that the incorporation of the 3,6‐silafluorene unit into the poly(2,7‐silafluorene) main chain can not only improve the color purity of the devices from the resulting copolymer but also enhance its device efficiency. Moreover, no undesired long‐wavelength green emission was observed in the PL spectra of P36‐27SiF90 compared to that of PFO with a dominating emission at 500–600 nm after thermal annealing at 200 °C for 8 h. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4941–4949, 2007 相似文献
7.
Lei Xiao Xing Chen Jingjing Xu Kangcheng Chen Jianhua Fang 《Journal of polymer science. Part A, Polymer chemistry》2019,57(23):2304-2313
A series of novel side‐chain sulfonated poly(arylene ether sulfone) (SPAES) multiblock and random copolymers were synthesized by condensation polymerization from a new disulfonated aryl sulfone monomer, 4,4′‐difluoro‐2,2′‐bis(3‐sulfobenzoyl)diphenyl sulfone disodium salt (DFBSPS). The chemical structures of DFBSPS and the SPAESs were characterized by proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FTIR) spectra. The SPAES membranes prepared by solution cast method exhibited high tensile strength (50–71 MPa) and high radical oxidative stability. They could keep their morphology and maintain proton conductivities after hydrolysis test in 95 °C water for 1000 h. They also showed smaller swelling ratio in in‐plane direction than in through‐plane direction and such an anisotropic effect was more significant for the multiblock copolymers than for the random ones. The multiblock copolymer membranes exhibited higher proton conductivity than the random ones with similar ion exchange capacities (IECs). Preliminary hydrogen‐oxygen fuel cell tests were performed at 60 °C and 80% relative humidity (RH). The results showed that the single cell equipped with the multibiock copolymer membrane SB3 exhibited 0.12 W cm?2 higher maximum output power density than the one equipped with the random copolymer membrane SR3 (with the same IEC), indicating much better performance of the former. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2304–2313 相似文献
8.
Elif Kurnaz Ekmel Helvacioglu Nur Cicek Kekec Nihan Nugay Turgut Nugay Joseph P. Kennedy 《Journal of polymer science. Part A, Polymer chemistry》2019,57(11):1197-1208
We report the synthesis of high‐molecular‐weight linear polyisobutylenes (PIBs) and PIB networks from low‐molecular‐weight PIB by thiol‐ene click chemistry. Thus, liquid allyl‐telechelic PIB was reacted with small di‐ and tri‐thiols, and the thiolated intermediates chain‐extended by UV‐ or thermally induced free radical initiation to linear and crosslinked products. PIB networks were also prepared by crosslinking SH‐telechelic PIB with a small triallyl compound. Linear products were characterized by 1H NMR spectroscopy and GPC, and networks by FTIR spectroscopy, extractables, swelling, and permanent set. The effect of reaction conditions (nature of thiol chain extender, concentration of photo‐ and thermal initiators, UV radiation time, and reagent concentrations) on chain extension and crosslinking was investigated. Under well‐defined conditions high‐molecular‐weight PIBs and tight PIB networks were prepared. Thiol‐ene click chemistry provides novel thiolated PIB derivatives and is a useful strategy for the convenient preparation of high‐molecular‐weight rubbery PIBs and tight PIB networks from low‐molecular‐weight PIB precursors. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 相似文献
9.
Xufeng Wu Gaoquan Shi Feng'En Chen Shaohu Han Junbiao Peng 《Journal of polymer science. Part A, Polymer chemistry》2004,42(12):3049-3054
Poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐p‐phenylenevinylene] (MEH‐PPV) with a molar mass of 26–47 × 104 g mol?1 and a polydispersity of 2.5–3.2 was synthesized by a liquid–solid two‐phase reaction. The liquid phase was tetrahydrofuran (THF) containing 1,4‐bis(chloromethyl)‐2‐methoxy‐5‐(2′‐ethylhexyloxy)benzene as the monomer and a certain amount of tetrabutylammonium bromide as a phase‐transfer catalyst. The solid phase consisted of potassium hydroxide particles with diameters smaller than 0.5 mm. The reaction was carried out at a low temperature of 0 °C and under nitrogen protection. No gelation was observed during the polymerization process, and the polymer was soluble in the usual organic solvents, such as chloroform, toluene, THF, and xylene. A polymer light‐emitting diode was fabricated with MEH‐PPV as an active luminescent layer. The device had an indium tin oxide/poly(3,4‐ethylenedioxylthiophene) (PEDOT)/MEH‐PPV/Ba/Al configuration. It showed a turn‐on voltage of 3.3 V, a luminescence intensity at 6.1 V of 550 cd/m2, a luminescence efficiency of 0.43 cd/A, and a quantum efficiency of 0.57%. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3049–3054, 2004 相似文献
10.
Hiroshi Aoki Ken Hosoya Tomohisa Norisuye Nobuo Tanaka Daisuke Tokuda Norio Ishizuka Kazuki Nakanishi 《Journal of polymer science. Part A, Polymer chemistry》2006,44(2):949-958
An investigation was made of the gelation of dimethacrylate‐type crosslinking agents in view of an application for separation media. The study mainly centered on a crosslinking agent, glycerol dimethacrylate (GDMA), which is relatively hydrophilic because of a hydroxyl group in the middle of its structure. The gelation of GDMA was compared with that of other hydrophobic crosslinking agents such as ethylene glycol dimethacrylate and 1,6‐hexanediol dimethacrylate. The diluents used in the study were toluene, toluene with methanol, and cyclohexanol. The gelation was observed in real time with a charge coupled device camera and dynamic light scattering (DLS). Also, the separated dry gels were extensively characterized with scanning electron microscopy, BET (N2 absorption and desorption isotherm), and Fourier transform infrared. DLS analysis showed a stronger molecular interaction of GDMA gelation in toluene, whereas this interaction was much weaker in an alcoholic solvent such as toluene with methanol or cyclohexanol. This indicated that GDMA gelation might proceed through hydrogen bonding as well as a crosslinking reaction of vinyl groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 949–958, 2006 相似文献
11.
《化学:亚洲杂志》2017,12(22):2950-2955
Cyanobacteria blooms possess serious threats to water resources. Herein, we report the synthesis of polyanionic membranes (PA‐M) by in situ photo‐crosslinking of a sulfate‐based anionic monomer followed by cation‐exchange with metal cations, Fe3+ (PA‐Fe), Cu2+ (PA‐Cu), or Zn2+ (PA‐Zn). The effect of cations on the anti‐cyanobacterial activities against both Microcystis aeruginosa (M. aeruginosa ) and Anabaena flos‐aquae (A. flos‐aquae ) was investigated. All the prepared metal‐containing membranes (PA‐Fe, PA‐Cu, PA‐Zn) exhibit high anti‐cyanobacterial activities and long‐term anti‐cyanobacterial stability, demonstrating that the synthesized PA‐M membranes can be used as an effective and safe inhibitor to control cyanobacterial blooms. 相似文献
12.
Lijun Fan Hou Chen Gaojian Lv Jinli Cao Yidong Fu 《Journal of polymer science. Part A, Polymer chemistry》2013,51(15):3233-3239
Crosslinking copolymerization of butyl methacrylate with a small amount of divinylbenzene (DVB) was carried out using single‐electron transfer‐living radical polymerization initiated with carbon tetrachloride (CCl4) and catalyzed by Cu(0)/N‐ligand in N,N‐dimethylformamide to produce a highly oil‐absorbing gel. The polymerization, gelation process, and oil‐absorbing properties were studied in detail. Analysis of monomer conversion with reaction time showed that the polymerization followed first‐order kinetics for both linear and crosslinking polymerization before gelation. Higher levels of DVB led to earlier gelation and the influence of N‐ligand on gelation was also significant. Under optimal conditions, oil absorption of the prepared gel to chloroform could reach 42.1 g·g?1. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3233–3239 相似文献
13.
Poly(N‐isopropylacrylamide) (PNIPAAm)‐based microspheres were prepared by precipitation and dispersion polymerization. The effects of several reaction parameters, such as the type and concentration of the crosslinker (N,N′‐methylenebisacrylamide or ethylene dimethacrylate), medium polarity, concentration of the monomer and initiator, and polymerization temperature, on the properties were examined. The hydrogel microspheres were characterized in terms of their chemical structure, size and size distribution, and morphological and temperature‐induced swelling properties. A decrease in the particle size was observed with increasing polarity of the reaction medium or increasing concentration of poly(N‐vinylpyrrolidone) as a stabilizer in the dispersion polymerization. The higher the content was of the crosslinking agent, the lower the swelling ratio was. Too much crosslinker gave unstable dispersions. Although the solvency of the precipitation polymerization mixture controlled the PNIPAAm microsphere size in the range of 0.2–1 μm, a micrometer range was obtained in the Shellvis 50 and Kraton G 1650 stabilized dispersion polymerizations of N‐isopropylacrylamide in toluene/heptane. Typically, the particles had fairly narrow size distributions. Copolymerization with the functional glycidyl methacrylate monomer afforded microspheres with reactive oxirane groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 968–982, 2006 相似文献
14.
Temperature‐Modulated Water Filtration Using Microgel‐Functionalized Hollow‐Fiber Membranes
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Daniel Menne Fee Pitsch Dr. John E. Wong Prof. Andrij Pich Prof. Matthias Wessling 《Angewandte Chemie (International ed. in English)》2014,53(22):5706-5710
In the present work, we investigate the potential of aqueous polymer microgels in membrane technology, especially for filtration applications. The poly(N‐vinylcaprolactam)‐based microgels exhibit thermoresponsive behavior and were employed to coat hollow‐fiber membranes used for micro‐ and ultrafiltration. We discuss the preparation of microgel‐modified membranes (by “inside‐out” as well as “outside‐in” filtration in dead‐end mode). The clean‐water permeability and stability of these membranes was studied not only as a function of time, but also of temperature. The microgel‐modified membranes exhibit a reversible thermoresponsive behavior whereby both the resistance and the retention increased with decreasing temperature. 相似文献
15.
Wenxin Fu Chang He Zhibo Li 《Journal of polymer science. Part A, Polymer chemistry》2012,50(7):1333-1341
Polymerizable tetrachloro‐perylenediimdes containing endo/exo‐norbornene groups on both imide sides were designed and synthesized. Endo/Exo‐type soluble ladder‐like polynorbornenes with perylenediimide (PDI) as bridges were prepared by ring‐opening metathesis polymerization (ROMP). XRD characterizations showed that the ladder‐like polynorbornenes had ordered structures similar to the supramolecular precursors assembled from the corresponding monomers. TGA measurements demonstrated great thermal stabilities for the both target P1‐Endo and P2‐Exo with Td of about 320 °C at 5 wt % loss, respectively, which is important for further application in devices. Both polymers have good solubility in common organic solvents and easy to form thin films. Photophysical studies and cyclic voltammetry investigations reveal that polynorbornene films have wide‐range absorption from 400 nm to 600 nm and the HOMO/LUMO energy levels could be matched well with the donor‐PCzTh‐TVDCN. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
16.
Haifeng Zhu Hui Tong Yongyang Gong Shiyang Shao Chunmei Deng Wang Zhang Yuan Yongming Zhang 《Journal of polymer science. Part A, Polymer chemistry》2012,50(11):2172-2181
Blue light‐emitting materials are receiving considerable academic and industrial interest due to their potential applications in optoelectronic devices. In this study, blue light‐emitting copolymers based on 9,9′ ‐ dioctylfluorene and 2,2′‐(1,4‐phenylene)‐bis(benzimidazole) moieties were synthesized through palladium‐catalyzed Suzuki coupling reaction. While the copolymer consisting of unsubstituted benzimidazoles (PFBI0) is insoluble in common organic solvents, its counterpart with N‐octyl substituted benzimidazoles (PFBI8) enjoys good solubility in toluene, tetrahydrofuran, dichloromethane (DCM), and chloroform. The PFBI8 copolymer shows good thermal stability, whose glass transition temperature and onset decomposition temperature are 103 and 428 °C, respectively. Its solutions emit blue light efficiently, with the quantum yield up to 99% in chloroform. The electroluminescence (EL) device of PFBI8 with the configuration of indium‐tin oxide/poly(ethylenedioxythiophene):poly(styrene sulfonic acid)/PFBI8/1,3,5‐tris(1‐phenyl‐1H‐benzimidazole‐2‐yl)benzene/LiF/Al emits blue light with the maximum at 448 nm. Such unoptimized polymer light‐emitting diode (PLED) exhibits a maximum luminance of 1534 cd/m2 with the current efficiency and power efficiency of 0.67 cd/A and 0.20 lm/W, respectively. The efficient blue emission and good EL performance make PFBI8 promising for optoelectronic applications. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
17.
Xiaohui He Yiwang Chen Yongming Liu Shuxian Yu Sanguo Hong Qing Wu 《Journal of polymer science. Part A, Polymer chemistry》2007,45(20):4733-4743
Norbornene polymerizations proceeded in toluene with bis(β‐ketoamino)nickel(II) {Ni[CH3C(O)CHC(NR)CH3]2 [R = phenyl ( 1 ) or naphthyl ( 2 )]} complexes as the catalyst precursors and the organo‐Lewis compound tris(pentafluorophenyl)borane [B(C6F5)3] as a unique cocatalyst. The polymerization conditions, such as the cocatalyst/catalyst ratio (B/Ni), catalyst concentration, monomer/catalyst ratio (norbornene/Ni), polymerization temperature, and polymerization time, were studied in detail. Both bis(β‐ketoamino)nickel(II)/B(C6F5)3 catalytic systems showed noticeably high conversions and activities. The polymerization activities were up to 3.64 × 107 g of polymer/mol of Ni h for complex 1 /(B(C6F5)3 and 3.80 × 107 g of polymer/mol of Ni h for complex 2 /B(C6F5)3, and very high conversions of 90–95% were maintained; both polymerizations provided high‐molecular‐weight polynorbornenes with molecular weight distributions (weight‐average molecular weight/number‐average molecular weight) of 2.5–3.0. The achieved polynorbornenes were confirmed to be vinyl‐addition and atactic polymers through the analysis of Fourier transform infrared, 1H NMR, and 13C NMR spectra, and the thermogravimetric analysis results showed that the polynorbornenes exhibited good thermal stability (decomposition temperature > 410 °C). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4733–4743, 2007 相似文献
18.
A series of amphiphilic conetworks of different compositions comprising poly(ethylene glycol) and poly(dimethylsiloxane) nanodomains were made, and their cocontinuity was characterized via separate swelling in water and n‐heptane and simultaneous swelling in water/n‐heptane mixtures. The extent and rate of swelling were determined and analyzed. The swelling of the cocontinuous hydrophilic poly(ethylene glycol) and hydrophobic poly(dimethylsiloxane) domains progressed independently of each other, and morphological changes, which occurred during swelling, influenced the rate of swelling. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1474–1481, 2006 相似文献
19.
Ashok K. Pandey Ronald F. Childs Marcia West John N. A. Lott Brian E. McCarry James M. Dickson 《Journal of polymer science. Part A, Polymer chemistry》2001,39(6):807-820
Robust, polyelectrolyte‐filled, microporous membranes were prepared by the introduction and crosslinking of a preformed polymer within the pores of a poly(propylene) host membrane. Specifically, poly(vinylbenzyl chloride) (PVBCl) was reacted with piperazine or 1,4‐diaminobicyclo[2.2.2]octane in an N,N‐dimethylformamide (DMF) solution contained in the pores of the microporous base membrane. The remaining chloromethyl groups were reacted with an amine, such as trimethylamine, to form positively charged ammonium sites. This simple two‐step procedure gave dimensionally stable, anion‐exchange membranes in which the degree of crosslinking and the mass loading were determined by the concentration of PVBCl and crosslinker in the starting DMF solution. The incorporated polyelectrolyte gel was evenly distributed within the pores of the host membrane with no surface layers present. The membranes are fully characterized. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 807–820, 2001 相似文献
20.
Kyung‐Min Kim Yoshiki Chujo 《Journal of polymer science. Part A, Polymer chemistry》2001,39(22):4035-4043
Liquid‐crystalline (LC) hybrid polymers with functionalized silsesquioxanes with various proportions of LC monomer were synthesized by the reaction of polyhedral oligomeric silsesquioxane (POSS) macromonomer with methacrylate monomer having an LC moiety under common free‐radical conditions. The obtained LC hybrid polymers were soluble in common solvents such as tetrahydrofuran, toluene, and chloroform, and their structures were characterized with Fourier transform infrared, 1H NMR, and 29Si NMR. The thermal stability of the hybrid polymers was increased with an increasing ratio of POSS moieties as the inorganic part. Because of the steric hindrance caused by the bulkiness of the POSS macromonomer, the number‐average molecular weight of the hybrid polymers gradually decreased as the molar percentage of POSS in the feed increased. Their liquid crystallinities were very dependent on the POSS segments of the hybrid polymers behaving as hard, compact components. The hybrid polymer with 90 mol % LC moiety (Cube‐LC90) showed liquid crystallinity, larger glass‐transition temperatures, and better stability with respect to the LC homopolymer. The results of differential scanning calorimetry and optical polarizing microscopy showed that Cube‐LC90 had a smectic‐mesophase‐like fine‐grained texture. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4035–4043, 2001 相似文献