共查询到20条相似文献,搜索用时 15 毫秒
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E. Del Rio G. Lligadas J. C. Ronda M. Galià V. Cádiz 《Journal of polymer science. Part A, Polymer chemistry》2010,48(22):5009-5017
A series of poly(ether urethane) networks were synthesized from polyether polyols obtained by ionic‐coordinative polymerization of epoxidized methyl oleate (EMO) using 4,4′‐methylenebis(phenyl isocyanate) or l ‐lysine diisocyanate as coupling agents. Moreover, a variety of segmented poly(ether urethane) networks with different hard segment contents were obtained using 1,3‐propanediol as the chain extender. The materials were characterized by differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis, and tensile properties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
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Shana P. Bunker Richard P. Wool 《Journal of polymer science. Part A, Polymer chemistry》2002,40(4):451-458
The focus of this work is to synthesize a monomer from a fatty acid methyl ester capable of forming high molecular weight polymers. The mono‐unsaturation in the starting material, methyl oleate, was first epoxidized using a peroxy acid. This intermediate material was further modified using acrylic acid. The acrylated molecule is able to participate in free‐radical polymerization reactions to form high molecular weight polymers. The rate of polymerization was low because of the long aliphatic structure of the monomer. It is hypothesized that the polymerization reaction occurred in the interface between the particle and water, thereby slowing down the reaction. After 18 h of reaction, a monomer conversion of approximately 91% was achieved. A maximum weight‐average molecular weight of approximately 106 g/mol was observed after 14 h of reaction. At early reaction times linear polymers were formed. However, as the reaction time increased, the amount of branching that occurred on the polymer molecule increased, as indicated by gel permeation chromatography and light scattering. This has been attributed to chain transfer to polymer via hydrogen abstraction from a tertiary backbone C–H bond. The resulting polymer may be of considerable interest for pressure‐sensitive adhesive applications. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 451–458, 2002; DOI 10.1002/pola.10130 相似文献
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Synthesis and properties of renewable nonisocyanate polyurethanes (NIPUs) from dimethylcarbonate 下载免费PDF全文
Charlotte Duval Nasreddine Kébir Agathe Charvet Amélie Martin Fabrice Burel 《Journal of polymer science. Part A, Polymer chemistry》2015,53(11):1351-1359
Novel fully renewable AA‐BB type nonisocyanate polyurethanes (NIPUs) were synthesized using the transurethanization approach. Dicarbamate monomers were prepared by the reaction of a diamine with an excess of dimethylcarbonate (DMC), in presence of 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene (TBD) as catalyst. Then, the dicarbamate was reacted with a diol to afford the polymer, in presence of TBD or K2CO3 as catalyst. Several renewable diamines and diols were tested. The two steps were conducted under neat conditions. The obtained materials exhibited Tg values varying from ?38 to 42 ° C, Tm values varying from 42 to 204 °C , and thermal stabilities above 200 ° C. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1351–1359 相似文献
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Kazuhiko Hashimoto Naoya Hashimoto Takehiko Kamaya Junya Yoshioka Haruki Okawa 《Journal of polymer science. Part A, Polymer chemistry》2011,49(4):976-985
Four kinds of bio‐based polyurethanes bearing hydroxy groups in the pendants were synthesized by the polyaddition of D ‐mannitol‐ and D,L ‐erythritol‐derived diols (1,2:5,6‐di‐O‐isopropylidene‐D ‐mannitol and 1,2‐O‐isopropylidene‐D,L ‐erythritol) with hexamethylene diisocyanate and methyl (S)‐2,6‐diisocyanatohexanoate and the subsequent deprotection of the isopropylidene groups. They were hydrolyzed much more quickly than the corresponding protected polyurethanes at 50 °C and pH 7.0, although their hydrolytic degradation rate was lower than that of polyurethanes with saccharic and glucuronic lactone groups, which had been reported in our previous articles. The introduction of D ‐mannitol units to the polyether‐polyurethanes containing poly(oxytetramethylene) glycol units also enhanced their hydrolyzibility. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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Romina Marín Sebastián Muñoz‐Guerra 《Journal of polymer science. Part A, Polymer chemistry》2008,46(24):7996-8012
A set of novel linear polyurethanes was synthesized by reaction in solution of 1,6‐hexamethylene diisocyanate (HDI) or 4,4′‐methylene‐bis(phenyl diisocyanate) with 2,3‐acetalized threitols, specifically, 2,3‐O‐methylidene‐L ‐threitol and 2,3‐O‐isopropylidene‐D ‐threitol. The polyurethanes containing acetalized threitols had weight‐average molecular weights between 40,000 and 65,000 Da. Most of them were amorphous and they displayed Tg higher than their unsubstituted analogs. Deprotection of acetalized polyurethanes by treatment with acid allowed preparing semicrystalline polyurethanes bearing two free hydroxyl groups in the repeating unit. The crystalline structure and crystallizability of the hydroxylated polyurethane made from HDI were investigated taken as reference the polyurethane made from 1,4‐butanediol and HDI. The hydrolytic degradability of threitol derived polyurethanes was comparatively evaluated under a variety of conditions. Highest degradation rates were obtained upon incubation at pH 10 at temperatures above Tg, the aliphatic hydroxylated polyurethane being the fastest degrading compound. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7996–8012, 2008 相似文献
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A novel bioresin, epoxidized soybean oil was synthesized by in situ method and was characterized employing FTIR and NMR. The bioresin was blended with epoxy(DGEBA) at different ratios as reactive diluents for improved processibility and toughened nature. The composition with 20 wt% bioresin exhibited improved impact strength to the tune of 60% as compared to virgin epoxy. Fracture toughness parameters critical stress intensity factor(KIC) and critical strain energy release rate(GIC) were evaluated using single edge notch bending test and demonstrated superior enhancement in toughness. Dynamic mechanical, thermal, thermo mechanical and fracture morphological analyses have been studied for bio-based epoxy blends. Curing kinetics has been evaluated through DSC analysis to investigate the effect of bioresin on cross-linking reaction of neat epoxy with triethylenetetramine as curing agent. 相似文献
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Phuoc Dien Pham Vincent Lapinte Yann Raoul Jean‐Jacques Robin 《Journal of polymer science. Part A, Polymer chemistry》2014,52(11):1597-1606
Oleic acid and α,ω‐diacid were converted into propargylic esters followed by thiol‐ene/yne coupling (TEC/TYC) functionalization in presence of mercaptoethanol. The multiradical addition on fatty esters leads to the formation of lipidic polyols (OH1 and OH2), as judged by 1H NMR and mass spectroscopies as well as by size exclusion chromatography. The crosslinking reaction between TEC/TYC‐based polyols and 4,4′‐methylene bis(phenylisocyanate) isocyanate reactant was monitored by FTIR experiment and reaction parameters were optimized. By differential scanning calorimetry, relatively high glass transitions are measured corresponding to structure with little or without dangling chain. Moreover, the thermal stability of the resulting plant oil‐based polyurethane materials (PU1 and PU2) were found to be fully consistent with that of other lipidic PUs respecting a three‐step process. Thanks to TYC methodology, fatty α,ω‐diacid produces lipidic polyol without dangling chain and lipidic thermoset PU with relatively high Tg. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1597–1606 相似文献
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Zoran S. Petrovi Andrew Guo Wei Zhang 《Journal of polymer science. Part A, Polymer chemistry》2000,38(22):4062-4069
Four polyols were prepared by a ring opening of epoxidized soybean oil with HCl, HBr, methanol, and by hydrogenation. Two series of polyurethanes were prepared by reacting the polyols with two commercial isocyanates: PAPI and Isonate 2143L. Generally, the properties of the two series were similar. The crosslinking density of the polyurethane networks was analyzed by swelling in toluene. Brominated polyols and their corresponding polyurethanes had the highest densities, followed by the chlorinated, methoxylated, and hydrogenated samples. The polyurethanes with brominated and chlorinated polyols had comparable glass transition and strength, somewhat higher than the polyurethane from methoxy containing polyol, while the polyurethane from the hydrogenated polyol had lower glass‐transition and mechanical properties. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4062–4069, 2000 相似文献
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Leila Hojabri Xiaohua Kong Suresh S. Narine 《Journal of polymer science. Part A, Polymer chemistry》2010,48(15):3302-3310
A novel long chain linear unsaturated terminal diisocyanate, 1,16‐diisocyanatohexadec‐8‐ene (HDEDI) was synthesized from oleic acid via Curtius rearrangement. Its chemical structure was identified by FTIR, 1H NMR, 13C NMR, and HRMS. This diisocyanate was used as a starting material for the preparation of entirely bio‐based polyurethanes (PUs) by reacting it with canola diol and canola polyol, respectively. The physical properties and crystalline structure of the PUs prepared from this diisocyanate were compared to their counterparts prepared from similar fatty acid‐derived diisocyanate, 1,7‐heptamethylene diisocyanate (HPMDI). The HDEDI based PUs demonstrated various different properties compared to those of HPMDI based PUs. For example, HDEDI based PUs exhibited a triclinic crystal form; whereas HPMDI based PUs exhibited a hexagonal crystal lattice. In addition, canola polyol‐HDEDI PU demonstrated a higher tensile strength at break than that of canola polyol‐HPMDI, attributed to the higher degree of hydrogen bonding associated with the former sample. Nevertheless, lower Young's modulus and higher elongation in canola polyol‐HDEDI PU were obtained because of the flexibility of the long chain introduced by the HDEDI diisocyanate. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3302–3310, 2010 相似文献
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<正>A brominated hyperbranched polyether has been synthesized from cyanuric chloride and sodium salt of tetrabromobisphenol-A by an A_2+B_3 approach.The synthesized polyether was characterized by ~1H-NMR,~(13)C-NMR,UV, FTIR spectroscopy and X-ray diffraction studies,measurements of solution viscosity,molecular weight and solubility and elemental and thermogravimetric analyses.The flame retardancy of the synthesized polyether and its blends with commercially available plasticized poly(vinyl chloride)(PVC) and low density polyethylene(LDPE) was investigated by measurements of limiting oxygen index(LOI) value and thermogravimetric analysis.The properties are compared with a non-halogenated similar type of bisphenol-A based aromatic polyether after blending at different dose levels with the same base polymers.The LOI values of these blends indicated that these hyperbranched polyethers acted as flame retardant additives,and antimony trioxide had prominent synergistic effect with the bromo hyperbranched polyether for the above base polymers,and an increment of 4 to 6 units in LOI values was observed. 相似文献
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A series of liquid crystal α-[bis(2-hydroxyethyl)amino]-ω-(4-nitroazobenzene-4′-oxy)alkanes (Cn-diol) with different alkyl chain length has been synthesized. All Cn-diols exhibit a smectic phase that has been identified by means of polarizing microscopy and differential scanning calorimetry. These compounds are suitable monomers for the synthesis of side-chain liquid crystalline polyurethanes and polyesters. They were polymerized with hexamethylene diisocyanate to corresponding SCLC polyurethanes in which the spacer length was varied from 2 to 12 methylene units. Polyurethanes (CnP) with spacer lengths n ≥ 4 exhibited liquid crystalline behavior. Fourier transform infrared temperature studies of the CnP were done focusing on H-bonds between the N H and CO groups of the urethane backbone. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2871–2888, 1997 相似文献
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Enrique Del Rio Gerard Lligadas Juan Carlos Ronda Marina Galià Virginia Cádiz 《Journal of polymer science. Part A, Polymer chemistry》2011,49(14):3069-3079
2‐Nonyl‐2‐oxazoline and 2‐(9‐decenyl)‐2‐oxazoline have been copolymerized in different proportions by cationic ring‐opening polymerization to obtain a series of random linear copolymers with tailored molecular weight and double bond functionality in the side chains. Thiol‐ene addition of 2‐mercaptoethanol has been used to produce a set of polyoxazoline–polyols under mild conditions and with quantitative double bond transformation. The polyols obtained in this way were reacted with methylene‐bis(phenylisocyanate) to yield a series of amorphous and semicrystalline polyurethane networks. The thermal stability and the thermomechanical properties of these thermosets have been studied and related with the structure of the parent polyols. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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S. Kiran 《International Journal of Polymer Analysis and Characterization》2017,22(2):125-138
Synthesis and characterization of X-ray shielding thermoplastic polyurethane elastomers which are capable of blocking harmful radiation emitted by various sources are reported. X-ray shielding capability was generated in the polymer by covalently binding iodine atoms in a monomer and polymerizing it with other monomers such that the resultant polymer has the capability of shielding X-radiation. For rendering X-ray shielding capability to the polyurethane, Bisphenol-A (BPA) was iodinated to 4,4′-isopropylidinedi-(2,6-diiodophenol) (IBPA) and it was used as a chain extender during the synthesis of polyurethane. Polyurethanes were synthesized by reacting 1,6-diisocyanatohexane and IBPA with two different polyols, namely, poly(tetramethylene glycol) and poly(hexamethylene carbonate) diol. X-ray shielding polyurethanes (XPU) were characterized by infrared spectroscopy, thermogravimetry, dynamic mechanical analysis, energy-dispersive X-ray analysis, gel permeation chromatography, and X-radiography. Studies showed that by effectively changing polyol from polyether to polycarbonate, XPUs having different physicomechanical properties could be manufactured. Furthermore, these polyurethanes were also found to be noncytotoxic to L929 fibroblast cell lines. X-ray images revealed that the incorporation of IBPA has rendered X-ray opacity to the polyurethanes which are several times higher than the aluminum wedge of equivalent thickness. The materials are sufficiently flexible and rubbery, so can be used as coatings, films, or sheets for applications in energy sector, power-generating nuclear power plants, defense sector (bunkers for army personnel), medical applications (X-ray diagnostic and CT scanner rooms, gamma radiation therapy of cancer), etc. 相似文献
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E. Del Rio G. Lligadas J. C. Ronda M. Galià M. A. R. Meier V. Cádiz 《Journal of polymer science. Part A, Polymer chemistry》2011,49(2):518-525
The acyclic diene metathesis polymerization (ADMET) of 1,3‐di‐10‐undecenoxy‐2‐propanol, a castor oil based diene, is reported. 10‐Undecenol was used as renewable comonomer to end‐cap polymer chains and limit the molecular weight. The poly ols obtained in this way were reacted with 4,4′‐methylenebis(phenylisocyanate) (MDI) to yield a series of amorphous and semicrystalline polyurethane networks. The thermal stability and the thermomechanical and mechanical properties of these thermosets have been studied and showed good shape memory properties for the semicrystalline polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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Pin Hu Andreas Greiner Seema Agarwal 《Journal of polymer science. Part A, Polymer chemistry》2019,57(6):752-757
We present new side‐chain quaternized polyurethanes as antibacterial adhesives made by polyaddition polymerization followed by quaternization for different time intervals. The degree of quaternization of N‐diol units in the polymer is changed from 13.6 to 99.0 mol % (almost complete) for tuning the antibacterial action (leaching/contact type) and studying effect on adhesive strength. The degree of quaternization of about 26 mol % provided the nonleaching antibacterial effect with adhesive strength more than 60 N cm?2 on aluminum and glass substrates. The increase in the degree of quaternization enhanced polymer polarity shifting nonleaching (contact type) antibacterial behavior to the leaching type but maintaining the high adhesive strengths. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 752–757 相似文献
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Guichang Jiang Xinlin Tuo Dongrui Wang Qiang Li 《Journal of polymer science. Part A, Polymer chemistry》2009,47(13):3248-3256
Novel fluorinated polyurethanes (FPUs) were prepared by living radical polymerization of polyurethanes and hexafluorobutyl acrylate. The structures of the FPUs were characterized by FTIR, 1H NMR, GPC, DSC, and XPS. The fluorinated polyurethane polymerization was investigated and showed monomer conversion, and molecular weight increased with increasing reaction time. In this way, the fluorine content in polyurethane could be easily adjusted by controlling the content of the fluorinated acrylate monomer. The mechanical evaluation shows that FPUs exhibit good mechanical properties. Morphology of FPU films was observed by scanning electron spectroscopy. The effects of the fluorine content on the surface properties and oxidative stability of FPUs were investigated. FPUs films were devoid of significant surface degradation after immersion in 20% H2O2 and 0.1 M CoCl2 at 37 °C for 5 weeks. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3248–3256, 2009 相似文献