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1.
The radical copolymerization of styrene with methacrylic acid (MAA) initiated by triphenylbismuthonium 1,2,3,4‐tetraphenylcyclopentadienylide in dioxan at 80 ± 0.1 °C for 3 h results in the formation of alternating copolymer as evidenced from the values of reactivity ratios as r1 (styrene) = 0.03 and r2 (MAA) = 0.025. The kinetic expression is Rp α [I]0.5 [Sty] [MAA] and overall energy of activation is computed to be 23 kJ/mol. The FTIR spectrum of the copolymer shows the presence of bands at 3054 cm?1 assigned to the phenyl group of styrene and at 1724 cm?1 assigned to the ? COOH group of MAA. The 1H‐NMR spectrum of the copolymer shows peaks between 7.20 and 7.27 δ assigned to the phenyl protons of styrene and at 12.5 δ assigned to the COOH proton of MAA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1838–1843, 2005 相似文献
2.
Biodegradable copolymers of 2‐methylene‐1,3‐dioxepane (MDO) and styrene (ST) were synthesized by free‐radical copolymerization using di‐t‐butyl peroxide (DTBP) as the initiator. The copolymers containing ester units were characterized by Fourier transform infrared (FTIR), 1H‐NMR, and 13C‐NMR spectroscopy. Their molecular weight and polydispersity index were determined by gel permeation chromatography (GPC). In vitro enzymatic degradation of poly(MDO‐co‐ST) was performed at 37°C in phosphate buffer solution (PBS, pH = 7.4) in the presence of Pseudomonas lipase or crude enzyme extracted from earthworm. The experiment showed that incorporating ester units into C? C backbone chain of polystyrene would result in a biodegradable copolymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1146–1151, 2007 相似文献
3.
Novel hyperbranched polymers, which contain a hydrophobic branched poly(p‐(chloromethy)styrene) (PCMS) core and poly(N,N‐dimethylaminoethyl methacrylate) (PDMA) shell that exhibited environmental sensitivity, have been synthesized by atom transfer radical polymerization (ATRP). At first, a hyperbranched polymer (PCMS) core is obtained via ATRP of p‐(chloromethy)styrene (CMS), which may act as an “inimer”‐monomer and initiator. Then the modified hyperbranched polymers having different average arm length consisting of PCMS and PDMA are synthesized by ATRP using anterior PCMS as macroinitiators. Their macromolecular structures are characterized by FTIR and 1H NMR. Using chlorambucil as a model drug, the behaviors of the controlled drug release from the environmental‐sensitive hyperbranched polymers with different average chain length of PDMA and degree of branching are studied. The data demonstrate that the rate of the drug release can be effectively controlled by pH value, and these environmental‐sensitive hyperbranched polymers have the potential to be used as novel carriers in some controlled drug release systems in the future. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 311–316, 2006 相似文献
4.
Graft copolymerization of styrene onto poly(vinyl chloride) (PVC) and polypropylene (PP) was carried out in a supercritical CO2 medium using AIBN as a free radical initiator. The supercritical CO2 medium served as a reaction medium in addition to being a solvent for the styrene monomer and the free radical initiator. The reaction temperature and pressure were kept above the critical points of the solvent‐monomer mixture to form a homogeneous single‐phase medium. The resulting graft copolymers were characterized using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and nuclear magnetic resonance (NMR) techniques. The weight percent of grafting was determined using IR absorbance ratio technique. TGA results showed that the thermal stabilily of grafted copolymer of PVC was better than that of PVC, while grafted copolymer of PP had poorer thermal stability than PP. DSC results showed that glass transition temperatures (Tg's) of the grafted copolymers were higher than those of the starting polymers PVC and PP. The presence of polystyrene attached to the backbone polymer was confirmed by 1H NMR and 13C NMR analyses. 相似文献
5.
Katsuhiko Takenaka Satomi Kawamoto Masamitsu Miya Hiroki Takeshita Tomoo Shiomi 《Polymer International》2010,59(7):891-895
The presence of a bulky substituent at the 2‐position of 1,3‐butadiene derivatives is known to affect the polymerization behavior and microstructure of the resulting polymers. Free‐radical polymerization of 2‐triethoxysilyl‐1,3‐butadiene ( 1 ) was carried out under various conditions, and its polymerization behavior was compared with that of 2‐triethoxymethyl‐ and other silyl‐substituted butadienes. A sticky polymer of high 1,4‐structure ( ) was obtained in moderate yield by 2,2′‐azobisisobutyronitrile (AIBN)‐initiated polymerization. A smaller amount of Diels–Alder dimer was formed compared with the case of other silyl‐substituted butadienes. The rate of polymerization (Rp) was found to be Rp = k[AIBN]0.5[ 1 ]1.2, and the overall activation energy for polymerization was determined to be 117 kJ mol?1. The monomer reactivity ratios in copolymerization with styrene were r 1 = 2.65 and rst = 0.26. The glass transition temperature of the polymer of 1 was found to be ?78 °C. Free‐radical polymerization of 1 proceeded smoothly to give the corresponding 1,4‐polydiene. The 1,4‐E content of the polymer was less compared with that of poly(2‐triethoxymethyl‐1,3‐butadiene) and poly(2‐triisopropoxysilyl‐1,3‐butadiene) prepared under similar conditions. Copyright © 2010 Society of Chemical Industry 相似文献
6.
Multi‐arm star polystyrenes with hyperbranched polyester (HP3) core were prepared by atom transfer radical polymerization (ATRP). The structures of the polymers were investigated with FTIR and 1H NMR. GPC results showed that the resultant polymers had relatively broad polydispersity indices that arouse from the macromolecular initiator (HP3‐Br). The thermal properties were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC analysis indicated that polystyrene star polymers had only the glass transition temperatures (Tg), which changes with the weight ratio of multi‐functional macroinitiator‐to‐monomer. In addition, these star polymers could form the spherical micelles in the selected solvent (THF/n‐hexane). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 728–733, 2006 相似文献
7.
A comparative study on photoinitiated solution copolymerization of n‐butylacrylate (BA) with styrene (Sty) using pyrene (Py), 1‐acetylpyrene (AP), and 1‐(bromoacetyl)pyrene (BP) as initiators showed that the introduction of a chromophoric moiety, bromoacetyl (? COCH2Br), significantly increased the photoinitiating ability of pyrene. The kinetics and mechanism of copolymerization of BA with Sty using BP as photoinitiator have been studied in detail. The system follows nonideal kinetics (Rp ∝ [BP]0.34 [BA]1.07 [Sty]0.97). The nonideality was attributed to both primary radical termination and degradative initiator transfer. The monomer reactivity ratios of Sty and BA have been estimated by the Finemann–Ross and Kelen–Tudos methods, by analyzing copolymer compositions determined by 1H NMR spectra. The values of r1 (Sty) and r2 (BA) were found to be 0.78 and 0.25, respectively, which suggested the high concentration of alternating sequences in the random copolymers obtained. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3233–3239, 2006 相似文献
8.
Zhaoqiang Wu Lingzhi Meng Cheng Li Xiaoju Lu Lifen Zhang Yongbing He 《应用聚合物科学杂志》2006,101(4):2371-2376
Novel hydrophobic monomer N‐(1‐pyrenebutyryl)–N′‐methacryloyl hydrazide (PyMAHy) was synthesized and copolymerized with N‐vinylpyrrolidone (NVP) to get a series of amphiphilic copolymers. FTIR, 1H NMR, TEM, gel permeation chromatography–multi‐angle laser light scattering, UV–vis spectroscopy, and fluorescence spectroscopy were used to characterize these polymers. Results of fluorescence measurements show that these copolymers have good recognition ability to CO32? anion and the fluorescence emission intensity was quenched linearly upon the addition of CO32? anion. The recognition for CO32? anion was also proved by the results of TEM for the significantly difference in the morphology of copolymer before and after adding CO32? anion into copolymer Tris–HCl buffer solution. Results suggest the potential of these amphiphilic copolymers as fluorogenic chemosensor materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2371–2376, 2006 相似文献
9.
The free‐radical copolymerization of styrene and ethyl acrylate in benzene‐d6 as the solvent in the presence of benzoyl peroxide as an initiator at 70°C was studied by online 1H‐NMR spectroscopy. The chemical composition of the copolymer at different reaction times was calculated from the conversion of the monomers to the copolymer, and then the reactivity ratios of styrene and ethyl acrylate were determined at both low and high conversions. Data for the overall monomer conversion versus the time were used to estimate the ratio kpkt?0.5 for different compositions of the initial feed (kp is the propagation rate constant, and kt is the termination rate constant). kpk increased with an increasing molar fraction of ethyl acrylate in the initial feed. The monomer mixture and copolymer compositions versus the overall monomer conversion were calculated with the data of 1H‐NMR spectra. The incorporation of the styrene monomer into the copolymer structure was more favored than that of the ethyl acrylate monomer. Reducing the molar fraction of styrene in the initial feed intensified this. Drawing the molar fraction of styrene (or ethyl acrylate) in the copolymer chains versus that in the initial feed showed a tendency of the system toward random copolymerization. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
10.
The poly(styrene‐co‐octavinyl‐polyhedral oligomeric silsesquioxane) (PS–POSS) organic–inorganic hybrid nanocomposites containing various percent of POSS were prepared via one‐step free radical polymerization and characterized by FTIR, high‐resolution 1H NMR, 29Si NMR, GPC, DSC, and TGA technologies. The POSS contents in these nanocomposites were determined using FTIR calibration curve. The result shows that the POSS contents in nanocomposites can be tailored by varying the POSS feed ratios. On the basis of the POSS contents in the nanocomposites and the 1H NMR spectra, the number of reacted vinyl groups of each octavinyl‐POSS macromonomer were calculated to be 6–8. DSC and TGA measurements indicate that the incorporation of POSS into PS homopolymer can apparently improve the thermal properties of the polymeric materials. The dramatic Tg and Tdec increases are mainly due to the formation of star and low cross‐linking structure of the nanocomposites, where POSS cores behave as the joint points and hinder the motion and degradation of the polymeric chains. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
11.
Radiation polymerization of acrylonitrile in a viscous system with styrene was performed at ambient temperature by using γ‐rays. It is found that the overall rate of polymerization was accelerated after critical conversion due to the gel effect. As the molar fraction of styrene in monomer feed (fSt) is increased, both the total polymer conversion and molar fraction of acrylonitrile in the copolymer feed (FAN) were decreased. The monomer reactivity ratios for acrylonitrile and styerne were determined to be r1 (AN) = 0.25 and r2 (St) = 2.0, respectively. The copolymers obtained were characterized by Fourier transformed infrared spectra (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), 1H‐NMR, and pyrolysis mass spectrometry (PMS). It was found that the slight addition of styrene to acrylonitrile strongly changes crystallinity, morphology, and thermal decomposition of the resulting polymer. 1H‐NMR measurment of AN/St copolymer showed the appearance of aromatic proton signals and shifted the resonance of the methylene proton to lower chemical shifts. The mass spectra of AN/St copolymers showed fragments of pyrolysates corresponding to oligonitriles with styrene end groups. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 268–275, 2002; DOI 10.1002/app.10324 相似文献
12.
In this study, synthesis, characterization, partial hydrolysis, and salt formation of poly(2‐hydroxyethyl methacrylate)‐co‐poly(4‐vinyl pyridine), (poly(HEMA)‐co‐poly‐(4‐VP)) copolymers were investigated. The copolymers were synthesized by free radical polymerization using K2S2O8 as an initiator. By varying the monomer/initiator ratio, chain lengths of the copolymers were changed. The copolymers were characterized by gel permeation chromatography (GPC), viscosity measurements, 1H and 13C NMR and FTIR spectroscopies, elemental analysis, and end group analysis methods. The copolymers were partially hydrolyzed by p‐toluene sulfonic acid monohydrate (PTSA·H2O) and washed with LiOH(aq) solution to prepare electrorheological (ER) active ionomers, poly(Li‐HEMA)‐co‐poly(4‐VP). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3540–3548, 2006 相似文献
13.
Hugo Xicohtencatl‐Serrano Manuel García‐Leiner Armando Cabrera‐Ortiz Rafael Herrera‐Nájera 《Polymer Engineering and Science》2014,54(10):2332-2344
This article reports the synthesis and characterization of four arm star‐shaped poly(styrene‐b‐[(butadiene)1?x‐(ethylene‐co‐butylene)x]‐b‐styrene) (SBEBS) copolymers. A series of SBEBS copolymers with different compositions of the elastomeric block were produced by hydrogenating a given poly(styrene‐b‐butadiene‐b‐styrene) (SBS) copolymer using a catalyst prepared from bis(η5‐cyclopentadienyl)titanium(IV) dichloride and n‐butyllithium. The characterization was accomplished by proton nuclear magnetic resonance spectroscopy (1H NMR), infrared spectroscopy (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). The results indicate that there is a selective saturation of the polybutadiene block over the polystyrene block; this selectivity was determined by the Ti/Li molar ratio and the concentration of Ti. It was observed that the saturation rate of the 1,2‐vinyl was higher than that of the 1,4‐trans and 1,4‐cis poly(butadiene)‐b isomers. The DSC and DMA results indicate that the degree of hydrogenation had a profound effect on the polymer's relaxation behavior. All samples exhibited a biphasic system behavior with two distinct transitions corresponding to the elastomeric and polystyrene blocks. SBEBS copolymers with higher saturation levels (>33%) exhibited a crystalline character. The TGA results indicated a characteristic weight loss temperature in all samples, with slightly higher thermal degradation stabilities in the materials with higher degrees of saturation. POLYM. ENG. SCI., 54:2332–2344, 2014. © 2013 Society of Plastics Engineers 相似文献
14.
Poly(epichlorohydrin) possessing chloromethyl side groups in the main chain was used in the atom transfer radical polymerization of methyl methacrylate and styrene to yield poly(epichlorohydrin‐g‐methyl methacrylate) and poly(epichlorohydrin‐g‐styrene graft copolymers. The polymers were characterized by 1H NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, and fractional precipitation method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2725–2729, 2006 相似文献
15.
Copolymers of 1‐vinyl‐1,2,4‐triazole (VTAz) and acrylic acid (AA) having different mole ratios were synthesized using free radical‐initiated solution polymerization in dimethylformamide at 70 °C with α,α′‐azobisisobutyronitrile as initiator in nitrogen atmosphere. The compositions of the synthesized copolymers for a wide range of monomer feeds were determined using Fourier transform infrared (FTIR) spectroscopy through recorded absorption bands for VTAz (1510 cm?1, C?N (triazole ring) stretching mode) and AA (1710 cm?1, C?O stretching mode) units. The structures of the copolymers were characterized using FTIR and 1H NMR spectroscopy. The copolymer compositions were also determined from 1H NMR analysis following proton signals of carboxyl group at 11.8–12.5 ppm of AA and of triazole ring at 7.5–8.1 ppm of VTAz. Monomer reactivity ratios for the VTAz‐AA pair were estimated using linear methods, i.e. Fineman–Ross (FR) and Kelen–Tüdös (KT). From FTIR evaluation, monomer reactivity ratios were calculated as r1 = 0.404 and r2 = 1.496 using the FR method and r1 = 0.418 and r2 = 1.559 using the KT method. These values were found to be very close to those obtained from NMR evaluation. The two cases r1r2 < 1 and r1 < r2 indicated the random distribution of the monomers in the final copolymers and the presence of a greater amount of AA units in the copolymer than in the feed, respectively. The observed relatively high activity of complexed growing radical‐AA? … VTAz was explained by the effect of complex formation between carbonyl groups and triazole fragments in chain growth reactions. Thermal behaviours of copolymers with various compositions were investigated using thermogravimetric and differential scanning calorimetric analyses. It was observed that thermal stabilities and glass transition temperatures of the copolymers increased resulting from complex formation between acid and triazole units. © 2012 Society of Chemical Industry 相似文献
16.
Vijay Kumar Patel Niraj Kumar Vishwakarma Avnish Kumar Mishra Chandra Sekhar Biswas Pralay Maiti Biswajit Ray 《应用聚合物科学杂志》2013,127(6):4305-4317
Two new alkyne‐terminated xanthate reversible addition‐fragmentation chain‐transfer (RAFT) agents: (S)‐2‐(Propynyl propionate)‐(O‐ethyl xanthate) (X3) and (S)‐2‐(Propynyl isobutyrate)‐(O‐ethyl xanthate) (X4) were synthesized and characterized and used for the controlled radical polymerization of N‐vinylpyrrolidone (NVP). X3 showed better chain transfer ability in the polymerization at 60°C. Molecular weight of the resulted polymer increased linearly with the increase in monomer loading. Kinetics study with X3 showed the pseudo‐first order kinetics up to 67% monomer conversion. Molecular weight (Mn) of the resulting polymer increased linearly with the increase in the monomer conversion up to around 67%. With the increase in the monomer conversion, polydispersity of the corresponding poly(NVP)s initially decreased from 1.34 to 1.32 and then increased gradually to 1.58. Chain‐end analysis of the resulting polymer by 1H‐NMR and FTIR showed clearly that polymerization started with radical forming out of xanthate RAFT agent. Living nature of the polymerization was also confirmed from the successful homo‐chain extension experiment and the hetero‐chain extension experiment involving synthesis of poly(NVP)‐b‐polystyrene amphiphilic diblock copolymer. Formed alkyne‐terminated poly(NVP) also allowed easy conjugation to azide‐terminated polystyrene by click chemistry to prepare well‐defined poly(NVP)‐b‐polystyrene block copolymers. Resulting polymers were characterized by GPC, 1H‐NMR, FTIR, and thermal study. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
17.
A bifunctional benzoxazine monomer, 6,6′‐bis(3‐methyl‐3,4‐dihydro‐2H‐benzo[e] [1,3]oxazinyl) sulfone (BS‐m), was synthesized from bisphenol‐S, methylamine, and formaldehyde via a solution method. The chemical structure of BS‐m was characterized with 1H and 13C‐nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and elemental analysis. The ring‐opening polymerization reaction of BS‐m monomer was studied by FTIR, 13C solid‐state NMR, and differential scanning calorimetry. With the polymerization reaction proceeding, the intensities of the FTIR absorption peaks of CH2, C? O? C, and C? N? C of the oxazine ring decreased gradually, and some of these absorption peaks disappeared. The shapes and intensities of the absorption peaks associated with benzene ring, sulfone group, and aromatic C? S bond changed in various ways. The changes in the solid‐state 13C‐NMR pattern, including chemical shifts, intensity of resonances, and line‐width, were observed from the spectra of BS‐m and the corresponding polybenzoxazine. The melting process of BS‐m overlapped with the beginning of the ring‐opening polymerization reaction. The polymerization kinetic parameters were evaluated for nonisothermal and isothermal polymerization of BS‐m. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
18.
Synthesis of TiO2−xNy/Ag‐PbMoO4 Composite and Their Photocatalytic Activity Under Simulated Solar Light Irradiation
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Tae‐Ho Kim Soo‐Wohn Lee Gobinda Gyawali Yong‐Hyun Jo Tohru Sekino 《International Journal of Applied Ceramic Technology》2015,12(3):577-584
TiO2?xNy/Ag‐PbMoO4 composite were synthesized by sonochemical method. The results revealed that the band‐gap energy absorption edge of TiO2?xNy/Ag‐PbMoO4 composite was shifted to a longer wavelength as compared to TiO2, TiO2?xNy, PbMoO4, and Ag‐PbMoO4. The TiO2?xNy/Ag‐PbMoO4 composite showed the enhanced photocatalytic activity for degradation of indigo carmine dye (ICD) under simulated solar light irradiation. The TiO2?xNy/Ag‐PbMoO4 composite exhibited the highest percentage (95.4%) of degradation of ICD and the highest reaction rate constant (0.0244 min?1) in 2 h. The results suggested that a good combination of Ag and TiO2?xNy nanoparticles has great influence on the photocatalytic behavior of PbMoO4. 相似文献
19.
Preparation and characterization of grafting styrene onto LLDPE by cyclohexane compatibilization in suspension polymerization
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A novel method of grafting styrene onto linear low‐density polyethylene (LLDPE) by suspension polymerization was systematically evaluated. Cyclohexane as a compatibilizer was introduced to swell and activate the surface of LLDPE molecular chain for amplifying the contact point of styrene monomer with LLDPE. A series of copolymer of grafting polystyrene (PS) onto LLDPE, known as LLDPE‐g‐PS, were prepared with different ratios of cyclohexane/styrene monomer and various LLDPE dosages. FTIR and 1H NMR techniques both confirmed successful PS grafting onto the LLDPE chains. In addition, SEM images of LLDPE‐g‐PS particles showed that the cross‐section morphology becomes smooth and dense with suitable cyclohexane dosages, indicating a better compatibility between LLDPE and PS. The highest grafting efficiency was 28.4% at 10 mL/g cyclohexane and styrene monomer when 8% LLDPE was added. In these conditions, the LLDPE‐g‐PS elongation at break increased by about 30 times compared with PS. Moreover, thermal gravimetric analysis (TGA) demonstrated that LLDPE‐g‐PS possesses much higher thermal stability than pure PS. Therefore, the optimal amount of cyclohexane as compatibilizer could increase the grafting efficiency and improve the toughness of PS. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41671. 相似文献
20.
Cellulose derivatives containing long hydrocarbon side chains and the carbazole chromophore are prepared. N‐4′‐Bromobutylcarbazole is first synthesized from carbazole and 1,4‐dibromobutane. Alkylated carbazole is then reacted with cellulose acetate in dimethyl sulfoxide solution to produce cellulose ethers containing the desired chromophore. Polymers containing a mixture of alkyl side chains are also prepared by the subsequent addition of 1‐bromododecane to the reaction mixture. Characterization of the resulting cellulose derivatives by FTIR spectroscopy indicates that the deacetylation of cellulose acetate and the subsequent etherification are both complete. In addition, the incorporation of the carbazole chromophore is clearly shown by 1H‐ and 13C‐NMR spectroscopy. Polymers of different carbazole content, ranging from 2.9 to 1.1 chromophores per anhydroglucose repeat unit, are obtained by varying the reaction conditions. Substitution is found to be controlled primarily by the quantity of alkylating agent introduced while variation of the reaction time has little effect. This method is used to prepare (dodecyl)y(N‐4′‐carbazolylbutyl)xcellulose, (decyl)y(N‐4′‐carbazolylbutyl)xcellulose, and (butyl)y(N‐4′‐carbazolylbutyl)xcellulose. Cellulose acetate can be replaced by (methyl)cellulose as the starting material to obtain analogous products. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2764–2772, 1999 相似文献