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Yasuo Shimano Kumiko Sato Shiro Kobayashi 《Journal of polymer science. Part A, Polymer chemistry》1995,33(16):2715-2723
Novel macromonomers and telechelics of poly(2-alkyl-2-oxazoline) (PROZO) were syn-thesized by utilizing termination of propagating species (2-oxazolinium ions) in the living polymerization of 2-alkyl-2-oxazoline (ROZO) with suitable nucleophiles. Two types of p-vinylbenzyl–type macromonomers were obtained by terminating living PROZO with sodium p-vinylbenzyl alkoxide or with sodium p-vinylbenzyl mercaptide. The synthesis of telechelics having a functional group (SH, COOH) on both ends of PROZO was achieved by using a bis(2-oxazolinium salt) initiator. The PROZO dithiol was synthesized by two methods: (1) termination of the living species on both ends with NaSH, and (2) aminolysis of PROZO bis(O-ethyldithiocarbonate) given by treatment of the living PROZO with potassium O-ethyldithiocarbonate. Termination of the living PROZO with the sodium salt of di-t-butyl malonate yielded a PROZO with di-t-butyl malonate moieties on both polymer ends, from which the PROZO dicarboxylic acid was derived via free tetracarboxylic acid. © 1995 John Wiley & Sons, Inc. 相似文献
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Hiroshi Uyama Yoichiro Honda Shiro Kobayashi 《Journal of polymer science. Part A, Polymer chemistry》1993,31(1):123-128
The present article describes the synthesis and emulsion copolymerization of a block-type amphiphilic poly(2-oxazoline) macromonomer possessing a polymerizable vinyl ester group. The macromonomer was synthesized by one-pot two-stage block copolymerization of 2-oxazolines using vinyl iodoacetate as initiator. 2-Methyl- and 2-n-butyl-2-oxazolines were employed for the construction of hydrophilic and hydrophobic segments, respectively. The surface activities evaluated by the surface tension of the macromonomer in water were fairly good. Emulsion copolymerization of vinyl acetate with the macromonomer was carried out. The macromonomer acted as a polymeric surfactant, as well as a comonomer. The resulting copolymer latex particles were spherical and their diameter was in the sub-micron range. The effects of the composition of the macromonomer on the emulsion copolymerization and the resulting latex particles were examined. © 1993 John Wiley & Sons, Inc. 相似文献
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Gao Bo Bengt Wessln K. Bodil Wesslen 《Journal of polymer science. Part A, Polymer chemistry》1992,30(9):1799-1808
Comb-shaped amphiphilic graft copolymers composed of hydrophobic backbones and hydrophilic side chains were prepared by radical copolymerization of poly(ethylene glycol) monomethacrylate macromonomers, and methacrylate and acrylate comonomers in toluene. The copolymerizations were very sensitive to the reaction conditions, and insoluble cross-linked gels were easily formed. The yields of soluble copolymers were affected by the initiator concentration, the macromonomer concentration, and the choice of chain transfer agents and comonomers. Solubilities of the copolymers in water or methanol were found to depend on the sizes and the numbers of the PEG side chains. The copolymers showed surface activity with CMC:s in the order of 0.1–1.5 g/L and surface tensions of 36–56 dyn/cm. When tested as emulsifiers most of the copolymers gave oil-in-water type emulsions at room temperature. Polymers carrying MPEG 2000 side chains were crystalline with melting points of 38–44°C, while those based on PEG 400 and 1000 were mostly amorphous with glass transition temperatures between -55 and -60°C. © 1992 John Wiley & Sons, Inc. 相似文献
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Binary blends of poly(vinyl chloride) (PVC) and chitin-graft-poly(2-methyl-2-oxazoline) showed miscibility in the blend fraction range of the latter lower than ca. 10 wt.-%. The glass transition temperature of PVC, which was determined by differential scanning calorimetry, changed to lower temperatures with increasing modified chitin contents up to 10 wt.-%. Segmental interaction between PVC and the graft copolymer was confirmed by the carbonyl stretching band shift in the FT-IR analysis. 相似文献
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Xiaoju Peng Anna Maria Hofmann Sascha Reuter Holger Frey J?rg Kressler 《Colloid and polymer science》2012,290(7):579-588
Interactions of the phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) with the amphiphilic diblock copolymer Ch-lPEG30-b-hbPG24 (ChP) are studied at the air–water interface by surface pressure–mean molecular area (π–mmA) measurements of mixed Langmuir films and adsorption measurements of ChP to the air–water interface covered with DPPC monolayers
at different initial surface pressure values π
0. ChP is composed of a single hydrophobic cholesteryl (Ch) moiety covalently bound to a diblock copolymer consisting of a
hydrophilic linear poly(ethylene glycol) (lPEG) block and a hydrophilic hyperbranched poly(glycerol) (hbPG) block. Langmuir isotherms and compression moduli of the mixed Langmuir films of different molar ratios reveal distinct
interactions between DPPC and ChP during compression. It is demonstrated that the behavior of the DPPC/ChP mixtures is dominated
by DPPC up to a molar ratio of 10:1, whereas the behavior is predominantly governed by ChP in mixtures with lower DPPC content
(molar ratios of 5:1, 2:1, and 1:1). In adsorption measurements, a strong affinity of ChP to DPPC is observed after injection
into the water subphase. The surface pressure value π
in up to which ChP is able to penetrate into DPPC monolayers is determined to the remarkably high value of 48.2 mN/m which attests
the favorable interactions between DPPC and the Ch moiety of ChP. Atomic force microscopy on LB films of DPPC/ChP mixtures
of different molar ratios transferred onto hydrophilic substrates confirms the presence of two different phases, a DPPC-rich
phase and a ChP-rich phase. 相似文献
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Koji Ishizu Takashi Fukutomi 《Journal of polymer science. Part A, Polymer chemistry》1987,25(1):23-30
Poly[styrene (ST)-tetrahydrofuran (THF)-2-methyl-2-oxazoline(MeOz)] triblock and graft copolymers were prepared by ionic polymerizations. Poly(ST-THF) graft copolymers were synthesized by coupling of ST-4-vinylpyridine (4VP) copolymer with a large excess of PTHF dication. The ion coupling of PST dianion with PTHF dication was accompanied by the side reaction (abstraction of α proton of oxonium ion). After tosylation of terminal hydroxyl groups of PTHF blocks, cationic copolymerizations of MeOz with poly(ST-THF) block and graft copolymers were carried out, and characteristics of produced copolymers were investigated in some detail. 相似文献
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Functional poly(ethylene oxide) star polymers possessing a tertiary amino group at each arm end were prepared by free-radical copolymerization of poly(ethylene oxide) macromonomers with divinylbenzene (DVB) in water or ethanol. The poly(ethylene oxide) arm was prepared by anionic polymerization using 2-[2-(N,N-dimethylamino)ethoxy]ethanol potassium alkoxide as the initiator. The star polymers had narrow molecular weight distribution. The arm number was controlled by varying the feed ratio [DVB]/[M], the initial concentration of macromonomer [M], and solvent media. The branching factor g' in methanol ([eta]S/[eta]L are the intrinsic viscosities of the star and linear molecules, respectively) exhibited a power-law dependence on the arm number, f, with a negative exponent. This means that the dimensions of a star were in agreement with the Daoud-Cotton scaling model. 相似文献
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Yoshiki Chujo Hisaaki Kobayashi Yuya Yamashita 《Journal of polymer science. Part A, Polymer chemistry》1989,27(6):2007-2014
Hydroxyl- or amino-terminated prepolymers were prepared by radical polymerization of methyl methacrylate in the presence of 2-mercaptoethanol or 2-aminoethanethiol hydrochloride, respectively, as a chain transfer agent. The resulting prepolymers were subjected to react with trimellitic anhydride to form aromatic dicarboxyl-terminated poly(methyl methacrylate)s. These condensation-type macromonomers and terephthalic acid were condensed with bisphenol-A to produce polyester–poly(methyl methacrylate) graft copolymers. 相似文献
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Poly(ethylene oxide) macromonomers carrying methoxy group on the one (α-) end and methacryloyloxyhexyl or methacryloyloxydecyl
group on the other (ω-) end were prepared, homopolymerized in water, and dispersion-copolymer-ized with styrene or methyl
methacrylate in a methanol–water mixture. They were found to polymerize more rapidly and to produce stable polystyrene dispersions
more effectively, as compared to the corresponding macromonomers carrying either α-methoxy and or α-dodecyloxy and ω-methacryloyloxy
end groups. Thus, the amphiphilic constitution of the macromonomers such that favors the polymerizing methacrylate end groups
to locally concentrate into the micelle core or to the particle surface while the poly(ethylene oxide) chains extending to
the medium appears to be most important in enhancing their polymerizability and effectiveness as reactive steric stabilizers.
On the other hand, stable poly(methyl methacry-late) particles with a number of craters or pleats on the surface were produced
with a PEO macromono-mer with α-methoxy and ω-methacryl-oyloxy end groups.
Received: 4 September 1996 Accepted: 18 October 1996 相似文献
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S. I. Kozlov G. Łapienis G. V. Rakova K. S. Kazanskii 《Polymer Science Series A》2006,48(10):1022-1034
Soluble comb-shaped and swelling network polymers based on monomethacrylate (M = 2080) and bismethacrylate (M = 4000) poly(ethylene oxide) macromonomers, have been synthesized by the controlled atom-transfer radical polymerization in aqueous media. PEG 2000 methyl ether ethyl-2-bromoisobutyrate and 2-bromoisobutyrate, in combination with CuBr, CuBr2, and 2,2′-bipyridyl, have been used as initiators. The length of the main chain of comb-shaped polymers, as estimated with multidetector chromatography, is in good agreement with the calculated values in the 15–20 range at M w /M n = 1.42–1.89. The polymerization of the methacrylate macromonomer proceeds at a high rate and with a nearly quantitative conversion. The replacement of 10–80 mol % CuBr with CuBr2 appreciably decelerates polymerization and decreases polydispersity to 1.14–1.21, while the experimental and calculated values of chain lengths remain equal. This finding indicates a higher level of process control. The polymer networks thus prepared manifest Gaussian elastic behavior, as is evident from the relationship between the elastic modulus G and the swelling degree Q that is consistent with the classical prediction G ~ Q m , where m = ?1/3. Within the framework of the accepted model of networks of this type, this fact suggests the short length of polymethacrylate chains. In addition, the relationship between the time of attainment of the gelation point and the composition of the initiation system agrees with the atomtransfer controlled polymerization mechanism. The efficiencies of various radical polymerization methods for controlling the network structure are compared. 相似文献
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A. V. Smirnova T. U. Kirila M. P. Kurlykin A. V. Tenkovtsev A. P. Filippov 《International Journal of Polymer Analysis and Characterization》2017,22(8):677-684
Eight-arm star-shaped poly(2-alkyl-2-oxazoline) (M?≈?21,000?g?·?mol?1) was studied by turbidimetry and light scattering in aqueous solutions within concentration ranging from 0.00038 to 0.0276?g?·?cm?3. The arms were the block copolymers of poly(2-isopropyl-2-oxazoline) (PiPrOx) and poly(2-ethyl-2-oxazoline) (PEtOx). Calix[8]arene core was connected with poly(2-isopropyl-2-oxazoline). The behavior of investigated polymer differed from that of thermosensitive stars with poly(2-alkyl-2-oxazoline) homopolymer arms. At low temperatures, the aggregates were formed due to interaction of hydrophobic cores. The phase separation temperatures T1 and T2 of studied star were higher than those for star-shaped poly(2-isopropyl-2-oxazoline) and lower than for poly(2-ethyl-2-oxazoline). T1 and T2 increased with dilution. 相似文献
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Koji Ishizu Satoshi Ishikawa Takashi Fukutomi 《Journal of polymer science. Part A, Polymer chemistry》1985,23(2):445-452
Well defined BAB-type poly[styrene(ST)-b-2-methyl-2-oxazoline(MeOz)] was prepared by the cationic polymerization of α,ω-p-toluenesulfonic acid ester-terminated PST (PST-BTs) as an initiator. Alkaline hydrolysis of this block copolymer was carried out under various reaction conditions to obtain BAB-type poly[ST-b-ethylene imine(EI)]. Morphologies of these block copolymer specimens cast from several solvents were observed by electron microscope. The results are discussed in some detail. 相似文献
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Brandon R. Clarke Gregory N. Tew 《Journal of polymer science. Part A, Polymer chemistry》2022,60(9):1501-1510
Herein it is reported how the overlap concentration (C*) can be used to overcome crosslinking due to diol impurities in commercial poly(ethylene glycol) (PEG), allowing for the synthesize of bottlebrush polymers with good control over molecular weight. Additionally, PEG-based bottlebrush networks are synthesized via ring-opening metathesis polymerization, attaining high conversions with minimal sol fractions (<2%). The crystallinity and mechanical properties of these networks are then further altered by solvent swelling with phosphate buffer solution and 1-ethyl-3-methylimidazolium ethyl sulfate/dichloromethane cosolvents. The syntheses reported here highlight the potential of the bottlebrush network architecture for use in the rational design of new materials. 相似文献
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Ming‐Qing Chen Akio Kishida Takeshi Serizawa Mitsuru Akashi 《Journal of polymer science. Part A, Polymer chemistry》2000,38(10):1811-1817
Polymeric nanospheres consisting of poly(methyl methacrylate) (PMMA) cores and poly(ethylene glycol) (PEG) branches on their surfaces were prepared by free radical copolymerization of methyl methacrylate (MMA) with PEG macromonomers in ethanol/water mixed solvents. PEG macromonomers having a methacryloyl (MMA‐PEG) and p‐vinylbenzyl (St‐PEG) end group were used. It has become clear that the obtained polymer dispersions form three kinds of states, particle dispersion (milky solution), clear solution, and gel/precipitation. It was found that the reaction parameters such as MMA concentration, molecular weight, and concentration of PEG macromonomers, and water content can affect nanosphere formation in a copolymerization system. The water volume fraction of mixed ethanol/water solvents affected the particle size of the nanospheres. These differences in the formation of nanospheres were due to the solvophilic/solvophobic balance between the copolymers and solvents during the self‐assembling process of the copolymers. The sizes of nanospheres can be controlled by varying concentration of PEG macromonomer and water content in solvents. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1811–1817, 2000 相似文献
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Serge Vetter Sabine Koch A. Dieter Schlüter 《Journal of polymer science. Part A, Polymer chemistry》2001,39(11):1940-1954
The synthesis of dendritic building blocks (dendrons) of the first generation (G1) and the second generation, which carry differently protected amine groups in the periphery, is reported. The dendrons are used for the synthesis of the corresponding acrylic and methacrylic macromonomers. Their polymerization behavior under radical conditions is investigated. The G1 dendronized polymers are decorated at their peripheral amino groups, that is, with the chiral amino acid L -phenylalanine by the attach-to approach. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1940–1954, 2001 相似文献
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Kuk Young Cho Chang-Hyeon Kim Jong-Woo Lee Jung-Ki Park 《Macromolecular rapid communications》1999,20(11):598-601
Poly(ethylene glycol) grafted poly(L -lactide) was prepared by ring opening polymerization of L -lactide and epoxy-terminated poly(ethylene glycol) methyl ether (PEGME). Stannous octoate and Al(Et)3·0.5 H2O were tested as polymerization catalysts, and Al(Et)3·0.5 H2O was found to be more effective for the ring-opening of the epoxy group of the modified PEGME monomer. The synthesized polymers were characterized by NMR and the efficiency of the incorporation of epoxy-terminated PEGME in the copolymer was determined. 相似文献