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1.
《Macromolecular rapid communications》2017,38(21)
To address the challenge of metal contamination, a “graft from” approach via organocatalyzed atom transfer radical polymerization (O‐ATRP) is developed to synthesize poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) (P(VDF‐co‐CTFE)) graft copolymers. N‐phenylphenothiazine is utilized as a model organic photoredox catalyst for catalyzing the (co)polymerization of methyl methacrylate (MMA), methacrylate (MA), and n‐butyl acrylate (BA). By employing this technique, high temporal control of polymerization and graft content are achieved. A series of P(VDF‐co‐CTFE)‐g‐PMMA, P(VDF‐co‐CTFE)‐g‐PMA, and P(VDF‐co‐CTFE)‐g‐PBA is prepared under mild conditions. The resultant graft copolymer can be used as macroinitiator to re‐initiate O‐ATRP to synthesize P(VDF‐co‐CTFE)‐g‐(PMMA‐b‐PMA), which might exhibit the potential application as novel dielectric material. 相似文献
2.
P. H. Lu G. N. Babu J. C. W. Chien 《Journal of polymer science. Part A, Polymer chemistry》1985,23(5):1421-1432
Copolymers of several compositions of methyl methacrylate (MMA), trichlorophenyl methacrylate (TCPMA), and tribromophenyl methacrylate (TBPMA) have been synthesized and characterized. Gamma radiolysis yields are very sensitive to the presence of the halogenated monomers. With less than 10% of the halogenated monomer in the copolymers. Gs values were found to be much greater than that of PMMA. However, the halogenated monomer introduces a tendency toward crosslinking. The results are consistent with the enhancement of chain scission by dissociative electron capture and the tendency of phenyl radical intermediates to cause crosslinking. These structure-property relationships were found to be valid for all the homopolymers and copolymers investigated in this series. 相似文献
3.
Hiroshi Ito Claudia Hrusa H. K. Hall Anne B. Padias 《Journal of polymer science. Part A, Polymer chemistry》1986,24(5):955-964
Alternating copolymers of styrene (St) with electron-deficient olefins trisubstituted or tetrasubstituted with cyano and carboalkoxy groups have been subjected to 60Co γ-radiolysis together with a series of copolymers of methyl methacrylate (MMA) and St. The chain scission susceptibility Gs—Gx determined by membrane osmometry drastically decreases as St is incorporated in poly(methyl methacrylate) (PMMA). Whereas the alternating St-MMA copolymer is slightly crosslinked upon irradiation, an alternating copolymer of St with diethyl 2-cyano-1,1-ethylenedicarboxylate maintains a fairly high degradation sensitivity (Gs—Gx = 1.2). The reactive-ion etch rates were determined for the series of polymers in CF4/O2 (92/8). The etch resistance is significantly increased by introduction of St units in PMMA, and the highly substituted alternating copolymer etches as slowly as the MMA(50)—St(50) copolymers. Thus the alternating copolymer of NCCH=C(CO2Et)2 with St behaves like PMMA when exposed to high-energy radiation but is comparable to PSt in plasma environments. 相似文献
4.
M. Rizvi A. Munir S. Zulfiqar M. Zulfiqar 《Journal of Thermal Analysis and Calorimetry》1995,45(6):1597-1604
Homopolymers of chlorotrifluoroethylene (CTFE), vinylidene fluoride (VDF) and methyl methacrylate (MMA) and their copolymers were studied by PGC/IR with regard to the separation and identification of the degraded products and clarification of the degradation mechanism. Besides monomers, HCl CO2, C2H2, HF, C5H10O2, C3F5Cl and dimers are the observed pyrolysis products. Mechanisms for different degradation reactions have also been studied. 相似文献
5.
Kie Yong Cho Seung Sang Hwang Ho Gyu Yoon Kyung‐Youl Baek 《Journal of polymer science. Part A, Polymer chemistry》2013,51(9):1924-1932
A series of ABA triblock copolymers of methyl methacrylate (MMA) and dodecyl methacrylate (DMA) [poly(MMA‐b‐DMA‐b‐MMA)] (PMDM) were synthesized by Ru‐based sequential living radical polymerization. For this, DMA was first polymerized from a difunctional initiator, ethane‐1,2‐diyl bis(2‐chloro‐2‐phenylacetate) with combination of RuCl2(PPh3)3 catalyst and nBu3N additive in toluene at 80 °C. As the conversion of DMA reached over about 90%, MMA was directly added into the reaction solution to give PMDM with controlled molecular weight (Mw/Mn ≤ 1.2). These triblock copolymers showed well‐organized morphologies such as body centered cubic, hexagonal cylinder, and lamella structures both in bulk and in thin film by self‐assembly phenomenon with different poly(methyl methacrylate) (PMMA) weight fractions. Obtained PMDMs with 20–40 wt % of the PMMA segments showed excellent electroactive actuation behaviors at relatively low voltages, which was much superior compared to conventional styrene‐ethylene‐butylene‐styrene triblock copolymer systems due to its higher polarity derived from the methacrylate backbone and lower modulus. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
6.
A series of amphiphilic graft copolymers of poly (vinylidene fluoride‐co‐chlorotrifluoroethylene)‐g‐poly(2‐vinyl pyridine), P (VDF‐co‐CTFE)‐g‐P2VP, with different degrees of P2VP grafting (from 26.3 to 45.6 wt%) was synthesized via one‐pot atom transfer radical polymerization (ATRP). The amphiphilic properties of P (VDF‐co‐CTFE)‐g‐P2VP graft copolymers allowed itself to self‐assemble into nanoscale structures. P (VDF‐co‐CTFE)‐g‐P2VP graft copolymers were introduced into neat P (VDF‐co‐CTFE) as additives to form blending membranes. When two different solvents, N‐methyl‐2‐pyrrolidone (NMP) and dimethylformamide (DMF), were used, specific organized crystalline structures were observed only in the NMP systems. P (VDF‐co‐CTFE)‐g‐P2VP played a pivotal role in controlling the morphology and pore structure of membranes. The water flux of the membranes increased from 57.2 to 310.1 L m?2 h?1 bar?1 with an increase in the PVDF‐co‐CTFE‐g‐P2VP loading (from 0 to 30 wt%) due to increased porosity and hydrophilicity. The flux recovery ratio (FRR) increased from 67.03% to 87.18%, and the irreversible fouling (Rir) decreased from 32.97% to 12.82%. Moreover, the pure gas permeance of the membranes with respect to N2 was as high as 6.2 × 104 GPU (1 GPU = 10–6 cm3[STP]/[s cm2 cmHg]), indicating their possible use as a porous polymer support for gas separation applications. 相似文献
7.
Chi-Yu Chen Charles U. Pittman John N. Helbert 《Journal of polymer science. Part A, Polymer chemistry》1980,18(1):169-178
The radiation degradation behavior of methyl α-chloroacrylate (MCA) and methacrylonitrile (MCN) copolymers has been investigated as part of a program to develop high-sensitivity polymeric resists for integrated circuit manufacture. High-molecular-weight copolymers were prepared by emulsion techniques. Several different copolymer compositions were prepared varying from 19 to 68 mole % MCA. These copolymers were fractionated and then subjected to γ irradiation from a 60Co Source. The Gs - Gs, Gs - 4Gs values were determined from M?;F>nk?1 and Gu?1 versus dose plots, and the Gfs and Gs Values were then calculated. Molecular weights of both unirradiated and irradiated polymers were analyzed by membrane osmometry and gel permeation chromatography. All copolymers exhibited higher degradation susceptibilities than that of poly(methyl methacrylate) (PPMA), which has Gx = 1.3. The individual Gx and Gx values of the copolymers were found to fall between those of the two homopolymers, poly(methyl α-chloroacrylate) (Gx = 6.0) and polymethacrylonitrile (Gx ~ 3.1). The dependence of Gx and Gx values on molecular weight was minor. The crosslinking susceptibility of the poly(methyl α-chloroacrylate) (Gx ~ 0.8), was greatly decreased by copolymerization with MCN. Relatively small amounts of MCN caused a large drop in Gx, i.e., Gx ~ 0.15 at 32% MCN and Gx ~ 0.03 at 51% MCN. The observation could be attributed to the decreasing probability that crosslinking sites, in the MCA monomer units on adjacent chains, would lie in close proximity. 相似文献
8.
Haldorai Yuvaraj Ha Soo Hwang Won Soo Kim Hyun Gyu Kim Euh Duck Jeong Kwon Taek Lim 《European Polymer Journal》2008,44(7):2253-2261
A series of non-fluorous random copolymers, composed of 3-[tris(trimethylsilyloxy)silyl] propyl methacrylate and 2-dimethylaminoethyl methacrylate, poly(SiMA-co-DMAEMA) with different comonomer ratios were prepared and utilized as stabilizers for the free radical dispersion polymerization of methyl methacrylate (MMA) in supercritical carbon dioxide (scCO2). It was demonstrated that the composition and concentration of the stabilizer have a dramatic effect on the morphology of resulting poly methyl methacrylate (PMMA) latex. When the copolymeric stabilizer poly(SiMA-co-DMAEMA) (71:29) was employed, free-flowing spherical PMMA particles were produced in high yield. As the concentration of stabilizer increases, the resulting size of colloidal particles decreases. In addition, the monomer concentration and initial pressure affected the particle diameter of PMMA. 相似文献
9.
Hongxiang Teng Liang Yang Frantisek Mikes Yasuhiro Koike Yoshiyuki Okamoto 《先进技术聚合物》2007,18(6):453-457
Copolymers of methyl methacrylate (MMA) with 2,3,5,6‐tetrafluorophenyl methacrylate (TFPMA), pentafluorophenyl methacrylate (PFPMA), and 4‐trifluoromethyl‐2,3,5,6‐tetrafluorophenyl methacrylate (TFMPMA) were investigated. All the three systems showed a random copolymerization character. The composition, glass transition temperature (Tg), and refractive index of the copolymers obtained were studied. Tgs of TFPMA/MMA and PFPMA/MMA copolymers were found to deviate positively from the Gordon–Taylor equation. However, Tgs of TFMPMA/MMA copolymers were well fit with the Gordon–Taylor equation. These results indicated the existence of interaction between MMA and either TFPMA or PFPMA units in copolymers. This interaction resulted in the enhancement of the Tg of MMA polymers through the copolymerization with TFPMA and PFPMA. The refractive index and the light transmittance of copolymers were close to those of PMMA. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
10.
Dingying Zhou Hongxiang Teng Koutarou Koike Yasuhiro Koike Yoshiyuki Okamoto 《Journal of polymer science. Part A, Polymer chemistry》2008,46(14):4748-4755
Fluoroalkyl methacrylates, 2,2,2‐trifluoroethyl methacrylate ( 1 ), hexafluoroisopropyl methacrylate ( 2 ), 1,1,1,3,3,3‐hexafluoro‐2‐methyl‐2‐propyl methacrylate ( 3 ), and perfluoro t‐butyl methacrylate ( 4 ) were synthesized. Homopolymers and copolymers of these fluoroalkyl methacrylates with methyl methacrylate (MMA) were prepared and characterized. With the exception of the copolymers of MMA and 2,2,2‐trifluoroethyl methacrylate ( 1 ), the glass transition temperatures (Tgs) of the copolymers were found to deviate positively from the Gordon‐Taylor equation. The positive deviation from the Gordon‐Taylor equation could be accounted for by the dipole–dipole intrachain interaction between the methyl ester group and the fluoroalkyl ester group of the monomer units. These Tg values of the copolymers were found to fit with the Schneider equation. The fitting parameters in the Schneider equation were calculated, and R2 values, the coefficients of determination, were almost 1.0. The refractive indices of the copolymers, measured at 532, 633, and 839 nm wavelengths, were lower than that of PMMA and showed a linear relationship with monomer composition in the copolymers. 2 and MMA have a tendency to polymerize in an alternating uniform monomer composition, resulting in less light scattering. This result suggests that the copolymer prepared with an equal molar ratio of 2 and MMA may have useful properties with applications in optical devices. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4748–4755, 2008 相似文献
11.
Yasuaki Kawamura Satoshi Nagai Juichi Hirose Yasaku Wada 《Journal of Polymer Science.Polymer Physics》1969,7(9):1559-1575
Dielectric constant and dielectric loss of copolymers of methyl methacrylate (MMA) with n-butyl methacrylate (nBMA) and isobutyl methacrylate (iBMA) have been measured in the frequency range 30 cps to 1 Mcps at temperatures from 70°K to 370°K. Results lead, together with those of previously published investigations on copolymers of MMA, to the following conclusions. (1) The loss-peak temperature attributed to side-chain relaxation (β peak) of PMMA varies with the comonomer ratio when the comonomer does not have an α-methyl group, but remains almost unchanged for comonomers having an α-methyl group. (2) In both cases, the β peak height of PMMA decreases with increasing ratio of comonomer B and completely vanishes for poly-B, and the loss peak temperature plotted against the fraction of B does not extrapolate to the β peak of poly-B. It is suggested on the basis of the above facts that the moving unit in the side-chain relaxation consists of a single side chain with a segment of the backbone chain and that the change in mobility of the side chain upon copolymerization results from the distortion of the helical structure of the backbone chain due to random distribution of α-methyl groups. Dielectric studies of the low-temperature side-chain relaxation (β2 peak) in PnBMA, poly(n-octyl methacrylate), and poly(n-dodecyl methacrylate) (130°K at 1 kcps) have been made and an interpretation is offered for the molecular nature of this relaxation. 相似文献
12.
Virgil Percec Tamaz Guliashvili Anatoliy V. Popov Ernesto Ramirez‐Castillo 《Journal of polymer science. Part A, Polymer chemistry》2005,43(9):1935-1947
A variety of conditions, including catalysts [CuCl, CuI, Cu2O, and Cu(0)], ligands [2,2′‐bipyridine (bpy), tris(2‐dimethylaminoethyl)amine (Me6‐TREN), polyethyleneimine, and hexamethyl triethylenetetramine], initiators [CH3CHClI, CH2I2, CHI3, and F(CF2)8I], solvents [diphenyl ether, toluene, tetrahydrofuran, dimethyl sulfoxide (DMSO), dimethylformamide, ethylene carbonate, dimethylacetamide, and cyclohexanone], and temperatures [90, 25, and 0 °C] were studied to assess previous methods for poly(methyl methacrylate)‐b‐poly(vinyl chloride)‐b‐poly(methyl methacrylate) (PMMA‐b‐PVC‐b‐PMMA) synthesis by the living radical block copolymerization of methyl methacrylate (MMA) initiated with α,ω‐di(iodo)poly(vinyl chloride). CH3CHClI was used as a model for α,ω‐di(iodo)poly(vinyl chloride) employed as a macroinitiator in the living radical block copolymerization of MMA. Two groups of methods evolved. The first involved CuCl/bpy or Me6‐TREN at 90 °C, whereas the second involved Cu(0)/Me6‐TREN in DMSO at 25 or 0 °C. Related ligands were used in both methods. The highest initiator efficiency and rate of polymerization were obtained with Cu(0)/Me6‐TREN in DMSO at 25 °C. This demonstrated that the ultrafast block copolymerization reported previously is the most efficient with respect to the rate of polymerization and precision of the PMMA‐b‐PVC‐b‐PMMA architecture. Moreover, Cu(0)/Me6‐TREN‐catalyzed polymerization exhibits an external first order of reaction in DMSO, and so this solvent has a catalytic effect in this living radical polymerization (LRP). This polymerization can be performed between 90 and 0 °C and provides access to controlled poly(methyl methacrylate) tacticity by LRP and block copolymerization. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1935–1947, 2005 相似文献
13.
O. A. Lam Y. Hervaud B. Boutevin 《Journal of polymer science. Part A, Polymer chemistry》2006,44(16):4762-4768
This article describes the homopolymerization of isocyanatoethyl methacrylate (IEM) and its copolymerization with methyl methacrylate (MMA) in acetonitrile in the presence of 2,2′‐azobisisobutyronitrile. The constant characteristic of IEM polymerizability (kp2/kte = 128 × 10?3 L mol?1 s?1, where kp is the propagation constant and kte is the termination constant) was determined. The study of IEM reactivity toward MMA gave ratios of 0.88 and 1.20 for IEM and MMA, respectively. The physicochemical properties of the IEM homopolymer and IEM/MMA copolymers were also studied. The glass‐transition temperature of poly(isocyanatoethyl methacrylate) was found to be 47 °C. From the thermogravimetric analysis of the weight‐loss percentage corresponding to the first wave of the thermogram, it was shown that the degradation mechanism of the IEM/MMA copolymers started from the isocyanate group. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4762–4768, 2006 相似文献
14.
Xin Hu Junjie Li Huayi Li Zhicheng Zhang 《Journal of polymer science. Part A, Polymer chemistry》2013,51(20):4378-4388
A series of 2,6‐bis(imino)pyridines, as common ligands for late transition metal catalyst in ethylene coordination polymerization, were successfully employed in single‐electron transfer‐living radical polymerization (SET‐LRP) of methyl methacrylate (MMA) by using poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) (P(VDF‐co‐CTFE)) as macroinitiator with low concentration of copper catalyst under relative mild‐reaction conditions. Well‐controlled polymerization features were observed under varied reaction conditions including reaction temperature, catalyst concentration, as well as monomer amount in feed. The typical side reactions including the chain‐transfer reaction and dehydrochlorination reaction happened on P(VDF‐co‐CTFE) in atom‐transfer radical polymerization process were avoided in current system. The relationship between the catalytic activity and the chemical structure of 2,6‐bis(imino)pyridine ligands was investigated by comparing both the electrochemical properties of Cu(II)/2,6‐bis(imino)pyridine and the kinetic results of SET‐LRP of MMA catalyzed with different ligands. The substitute groups onto N‐binding sites with proper steric bulk and electron donating are desirable for both high‐propagation reaction rate and C? Cl bonds activation capability on P(VDF‐co‐CTFE). The catalytic activity of Cu(0)/2,6‐bis(imino)pyridines is comparable with Cu(0)/2,2′‐bipyridine under the consistent reaction conditions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4378–4388 相似文献
15.
Temel Ozturk Sevil Savaskan Yilmaz Baki Hazer Yusuf Z. Menceloglu 《Journal of polymer science. Part A, Polymer chemistry》2010,48(6):1364-1373
This article reports the synthesis of the block and graft copolymers using peroxygen‐containing poly(methyl methacrylate) (poly‐MMA) as a macroinitiator that was prepared from the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in the presence of bis(4,4′‐bromomethyl benzoyl peroxide) (BBP). The effects of reaction temperatures on the ATRP system were studied in detail. Kinetic studies were carried out to investigate controlled ATRP for BBP/CuBr/bpy initiating system with MMA at 40 °C and free radical polymerization of styrene (S) at 80 °C. The plots of ln ([Mo]/[Mt]) versus reaction time are linear, corresponding to first‐order kinetics. Poly‐MMA initiators were used in the bulk polymerization of S to obtain poly (MMA‐b‐S) block copolymers. Poly‐MMA initiators containing undecomposed peroygen groups were used for the graft copolymerization of polybutadiene (PBd) and natural rubber (RSS‐3) to obtain crosslinked poly (MMA‐g‐PBd) and poly(MMA‐g‐RSS‐3) graft copolymers. Swelling ratio values (qv) of the graft copolymers in CHCl3 were calculated. The characterizations of the polymers were achieved by Fourier‐transform infrared spectroscopy (FTIR), 1H‐nuclear magnetic resonance (1H NMR), gel‐permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and the fractional precipitation (γ) techniques. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1364–1373, 2010 相似文献
16.
Hydroxy‐telechelic poly(methyl methacrylate)s of molecular weights below 5000 were obtained by atom transfer radical polymerization (ATRP) of methyl methacrylate followed by end‐capping with allyl alcohol via atom transfer radical addition (ATRA). As initiators for the ATRP, monofunctional initiators with an additional hydroxy group in the molecule or bifunctional initiators were employed. The successful synthesis of the hydroxy‐telechelic PMMA was proved by determination of their molecular weight using MALDI‐TOF‐MS. The efficiency of the end‐capping reaction was determined by 1H NMR spectroscopy using the allyl N‐(4‐tolyl)carbamate as end‐capping agent. Block copolymers comprising a poly(ethylene oxide) (PEO) block and a poly(methyl methacrylate) (PMMA) block were prepared by ATRP using a macroinitiator on the PEO basis. The dormant species of the macroinitiator consists of the phenyl chloroacetate moiety which shows a high rate of initiation. The successful synthesis of the poly(ethylene oxide)‐block‐poly(methyl methacrylate) was proved by 1H NMR spectroscopy; the ratios of EO/MMA repeating units in the feed and the copolymer were nearly equal. 相似文献
17.
Poly[2‐(3‐nitrocarbazolyl)ethyl methacrylate] (poly(NCzMA)) with controlled molecular weight and narrow molecular weight distribution was successfully synthesized using (methyl methacryloyl)potassium (MMA) as a weak initiator in the presence of diethylzinc (Et2Zn) in THF at –78°C. Et2Zn acted both as an additive for the coordination with enolate anion and nitro group and as a scavenger to remove impurities. Block copolymers PMMA‐block‐poly(NCzMA)‐block‐PMMA and poly(NCzMA)‐block‐PS‐block‐poly(NCz‐MA), were also synthesized quantitatively (PMMA: poly(methyl methacrylate), PS: polystyrene). The results indicate that Et2Zn can be used to synthesize the polymers of solid, nitro group‐containing methacrylate monomers by anionic polymerization in THF. 相似文献
18.
L. Sauguet B. Ameduri B. Boutevin 《Journal of polymer science. Part A, Polymer chemistry》2007,45(10):1814-1834
The radical co‐ and terpolymerization of perfluoro(4‐methyl‐3,6‐dioxaoct‐7‐ene) sulfonyl fluoride (PFSVE) with 1,1‐difluoroethylene (or vinylidene fluoride, VDF or VF2), hexafluoropropene (HFP), chlorotrifluoroethylene (CTFE), and bromotrifluoroethylene (BrTFE) is presented. Although PFSVE could not homopolymerize under radical initiation, it could be copolymerized in solution under a radical initiator with VDF, while its copolymerizations with HFP or CTFE led to oligomers in low yields. The terpolymerizations of PFSVE with VDF and HFP, with VDF and CTFE, or with VDF and BrTFE also led to original fluorinated terpolymers bearing sulfonyl fluoride side‐groups. The conditions of co‐ and terpolymerization were optimized in terms of the nature and the amount of the radical initiators, of the nature of solvents (fluorinated or nonhalogenated), and of the initial amounts of fluorinated comonomers. The different mol % contents of comonomers in the co‐ and terpolymers were assessed by 19F NMR spectroscopy. A wide range of co‐ and terpolymers containing mol % of PFSVE functional monomer ranging from 10 to 70% was produced. The kinetics of copolymerization of VDF with PFSVE enabled to assess the reactivity ratios of both comonomers: rVDF = 0.57 ± 0.15 and rPFSVE = 0.07 ± 0.04 at 120 °C. The thermal and physicochemical properties were also studied. Moreover, the glass transition temperatures (Tgs) of poly(VDF‐co‐PFSVE) copolymers containing different amounts of VDF and PFSVE were determined and the theoretical Tg of poly(PFSVE) homopolymer was deduced. Then, the hydrolysis of the ? SO2F into ? SO3H function was investigated and enabled the synthesis of fluorinated copolymers bearing sulfonic acid functions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1814–1834, 2007 相似文献
19.
Polystyrene macromonomers with different molecular weight were prepared by radical polymerization of styrene(St) in benzene using β-methacryloxylethyl 2-N,N-diethyldithiocarbamylacetate (MAEDCA) as a monomer-iniferter.Characterization of the macromonomer by ~1H-NMR showed that the end groups were α-methacrylyoxylethyloxycarbonyl-methyl and ω-(N,N-diethyldithiocarbamyl). The macromonomer was difficult to homopolymerize, but it was easilycopolymerized with methyl methacrylate (MMA) initiated by AIBN to form graft copolymers (PMMA-g-PSt) with PStbranches randomly distributed along the PMMA backbone. Copolymerization reaction and the structure of the graftcopolymers were strongly affected by M_n and concentration of the macromonomer. The composition and M_n of the purified graft copolymer were determined by ~1H-NMR and GPC analysis. 相似文献
20.
Hideyuki Kaneko Shin‐ichi Kojoh Nobuo Kawahara Shingo Matsuo Tomoaki Matsugi Norio Kashiwa 《Journal of polymer science. Part A, Polymer chemistry》2005,43(21):5103-5118
Graft and star copolymers having poly(methacrylate) backbone and ethylene–propylene random copolymer (EPR) branches were successfully synthesized by radical copolymerization of an EPR macromonomer with methyl methacrylate (MMA). EPR macromonomers were prepared by sequential functionalization of vinylidene chain‐end group in EPR via hydroalumination, oxidation, and esterification reactions. Their copolymerizations with MMA were carried out with monofunctional and tetrafunctional initiators by atom transfer radical polymerization (ATRP). Gel‐permeation chromatography and NMR analyses confirmed that poly(methyl methacrylate) (PMMA)‐g‐EPR graft copolymers and four‐arm (PMMA‐g‐EPR) star copolymers could be synthesized by controlling EPR contents in a range of 8.6–38.1 wt % and EPR branch numbers in a range of 1–14 branches. Transmission electron microscopy of these copolymers demonstrated well‐dispersed morphologies between PMMA and EPR, which could be controlled by the dispersion of both segments in the range between 10 nm and less than 1 nm. Moreover, the differentiated thermal properties of these copolymers were demonstrated by differential scanning calorimetry analysis. On the other hand, the copolymerization of EPR macromonomer with MMA by conventional free radical polymerization with 2,2′‐azobis(isobutyronitrile) also gave PMMA‐g‐EPR graft copolymers. However, their morphology and thermal property remarkably differed from those of the graft copolymers obtained by ATRP. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5103–5118, 2005 相似文献