共查询到20条相似文献,搜索用时 15 毫秒
1.
Yasuhiro Morisaki Hiromichi Otaka Kensuke Naka Yoshiki Chujo 《Macromolecular rapid communications》2009,30(11):948-953
We report a new method for the synthesis of block copolymers with a pentasilane core by the polymerization of alkyl methacrylate monomers using the pentasilyl dianion as an initiator. The polymerization proceeded with living features and yielded the corresponding block copolymers with controlled molecular weights. The amphiphilic block copolymer was obtained by the polymer reaction, and it formed sphere‐like aggregates in MeOH/H2O solution.
2.
Zhengguo Cai Yuushou Nakayama Takeshi Shiono 《Macromolecular rapid communications》2008,29(6):525-529
Polymerization of norbornene has been conducted with [t‐BuNSiMe2(3,6‐t‐Bu2Flu)]TiMe2 ( 1 ) in toluene at 20 °C using modified methylaluminoxane that contained 0.4 mol‐% of triisobutylaluminium (TIBA) (dMMAO(0.4)) or 1.8 mol‐% of TIBA (dMMAO(1.8)). The 1 ‐dMMAO(0.4) catalytic system undergoes a living polymerization of norbornene. The catalysis of norbornene and propylene with the 1 ‐dMMAO(1.8) catalytic system gives markedly different results because of differences in transfer times of the polymers from Ti to TIBA. The successive addition of norbornene and propylene before the complete consumption of the norbornene in the 1 ‐dMMAO(1.8) system gives monodisperse PNB‐block‐poly(propylene‐ran‐norbornene)‐block‐PP terminated with a Ti–PP bond, which is exchanged with TIBA. Hence the repeated addition of the same amount of norbornene and propylene realizes the catalytic synthesis of monodisperse block copolymer in this system.
3.
Ryuji Sugi Akihiro Yokoyama Tsutomu Yokozawa 《Macromolecular rapid communications》2003,24(18):1085-1090
Well‐defined telechelic‐type aromatic polyamides having a secondary amino group and a phenyl ester moiety at each chain end were prepared by the chain‐growth polycondensation of phenyl 4‐(octylamino)benzoate ( 1 ) with initiator 2 (N‐tert‐butoxycarbonylated 1 ), followed by deprotection of the N‐protecting group of the initiator unit. This polycondensation was applied to the synthesis of well‐defined di‐ and triblock copolymers of aromatic polyamides and poly(tetrahydrofuran) (poly(THF)) by the reaction of the terminal secondary amino group of the polyamide with the living cationic propagating group of poly(THF).
4.
Klaus Tauer Victor Khrenov Natasha Shirshova Nadine Nassif 《Macromolecular Symposia》2005,226(1):187-202
The preparation of some unique block copolymers and block copolymer particles via radical heterophase polymerization is described. Special emphasis is placed on double hydrophilic block copolymers such as poly(styrene sulfonic acid)-b-poly(methacrylic acid) diblock copolymer and double hydrophilic block copolymer particles consisting of both hydrophilic shells and cross-linked hydrophilic cores. Examples are given for the application of such particles as adsorbents, nano-reactors for chemical synthesis, and as colloidal stabilizers in both heterophase polymerization and biomineralization reactions. 相似文献
5.
以聚乙二醇甲基丙烯酸酯(PEGMA)为大分子引发剂进行ε-己内酯的酶催化开环聚合, 合成出嵌段共聚物, 然后将其转化成大分子引发剂型单体(Macroinimer), 最后通过原子转移自由基聚合(ATRP)制备出一种新型结构的嵌段型支化聚合物. 相似文献
6.
PCL-PEG-PCL嵌段共聚物的合成与性能 总被引:10,自引:0,他引:10
研究了氮气保护下,以辛酸亚锡和聚乙二醇为共引发剂,引发ε-己内酯的开环聚合反应。在聚乙二醇(PEG)链段分子量保持不变的情况下,全盛了不同分子量聚己丙酯链段的PCL-PEG-PCL三嵌段共聚物,以及不同分子量PEG链段而聚己内酯链段相同的嵌段共聚物。采用GPC、DSC、FTIR、^1H-NMR及吸水性测试等分析手段表征了共聚物的结构和性能。结果表明聚合反应为可控反应,可通过调整聚乙二醇与ε-己内酯的比例来控制聚合物的分子量;聚乙二醇组分的引入有效地改善了聚合物的亲水性,并破坏了其结晶性。 相似文献
7.
活性阳离子聚合法合成嵌段共聚物的研究进展 总被引:2,自引:0,他引:2
在80年代,阳离子聚合研究的一个最重要突破可能就是活性阳离子聚合。目前为止,有关活性阳离子聚合的新引发体系,新单体及合成应用等方面已取得巨大进展,本综述主要介绍利用活性阳离子聚合合成二、三元嵌段和多元嵌段共聚物的研究成果。 相似文献
8.
We present a combinatorial approach to the synthesis of block copolymer series by anionic polymerization, utilizing a specially designed reactor setup. The setup features one main reactor and three secondary reactors to carry out anionic polymerizations on laboratory‐scale quantities at low temperatures. The implementation was demonstrated with three series of AB‐ and ABC‐block copolymers with identical A‐ and AB‐blocks, respectively. The B‐block in AB‐diblock copolymers and the C‐block in ABC‐triblock copolymers can be varied with respect to block length or chemical constitution. Well‐defined series of block copolymers are useful for advanced optimization of functional block copolymers in nanotechnology applications.
9.
Yuri Matsuo Toshiyuki Oie Raita Goseki Takashi Ishizone Kenji Sugiyama Akira Hirao 《Macromolecular Symposia》2013,323(1):26-36
Five A-B-A′, A-C-A′, B-A-B′, C-A-C′, and C-B-C′ triblock terpolymers with block orders difficult to synthesize by sequential polymerization have been successfully synthesized by a new methodology combining living anionic polymers with a specially designed linking reaction using α-phenylacrylate as the reaction site. Here, A(A′), B(B′), and C(C′) represent groups of polymers (having chain-end anions with different nucleophilicities), which are only polymerizable from A(A′) to B(B′) to C(C′) via sequential polymerization. The corresponding polymers are polystyrene (A) and poly(α-methylstyrene) (A′), poly(2-vinylpyridine) (B) and poly(4-vinylpyridine) (B′) and polymers from methacrylate type monomers like poly(methyl methacrylate) (C), poly(tert-butyl methacrylate) (C′), poly(2-hydroxyethyl methacrylate) (C′), poly(2,3-dihydroxypropyl methacrylate) (C′), and poly(ferrocenylmethyl methacrylate) (C′). Furthermore, three synthetically difficult B-A-B, C-A-C, and C-B-C triblock copolymers with molecular asymmetry in both side blocks have also been synthesized by the developed methodology. All of the polymers thus synthesized are quite new triblock terpolymers and copolymers with well-defined structures, i.e., precisely controlled molecular weights, compositions and narrow molecular weight distributions (Mw/Mn ≤ 1.05). 相似文献
10.
Nicolas Gaillard Alain Guyot Jerome Claverie 《Journal of polymer science. Part A, Polymer chemistry》2003,41(5):684-698
Amphiphilic block copolymers of poly(acrylic acid‐b‐butyl acrylate) were prepared by reversible addition–fragmentation chain transfer polymerization in a one‐pot reaction. These copolymers were characterized by NMR, static and dynamic light scattering, tensiometry, and size exclusion chromatography. The aggregation characteristics of the copolymers corresponded to those theoretically predicted for a star micelle. In a butyl acrylate and methyl methacrylate emulsion polymerization, low amounts of these copolymers could stabilize latices with solid contents up to 50%. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 684–698, 2003 相似文献
11.
Functional ultra-high molecular weight transparent styrene-butadiene block copolymer possesses both high transparency and impact resistance and has excellent comprehensive properties prior to other transparent resins. In this paper we not only use anionic polymerization process which includes 1 time addition of initiator and 3 time addition of monomers, but also introduce functional coupling agent for the fist time to prepare mentioned functional block copolymer. The typical preparation proces… 相似文献
12.
Volker Abetz 《Macromolecular rapid communications》2015,36(1):10-22
The developments in membranes based on tailored block copolymers are reported with an emphasis on isoporous membranes. These membranes can be prepared in different geometries, namely flat sheets and hollow fibers. They display narrow pore size distributions due to their formation by self‐assembly. The preparation of these membranes and possibilities to further functionalize such membranes will be discussed. Different ways to control the pore size will be addressed, and the potential of block copolymer blends to fabricate membranes with tailored pore sizes will be shown.
13.
14.
Summary: The free‐radical addition of ω‐functional mercaptans to the vinyl double bonds of 1,2‐polybutadiene‐block‐poly(ethylene oxide) copolymers was used for modular synthesis of well‐defined functional block copolymers. The modification reaction proceeds smoothly and yields quantitatively functionalized block copolymers (1H NMR and FT‐IR spectroscopy) without disturbing the molecular‐weight distribution of the parent copolymer (PDI < 1.09, size exclusion chromatography).
15.
Tao Wu Ying Mei Chang Xu H. C. Michelle Byrd Kathryn L. Beers 《Macromolecular rapid communications》2005,26(13):1037-1042
Summary: Block copolymers of poly(ethylene oxide‐block‐2‐hydroxypropyl methacrylate) (PEO‐b‐PHPMA) with a range of molecular masses of the PHPMA block were obtained by controlled radical polymerization on a chip (CRP chip) using a PEO macroinitiator. A series of well‐controlled polymerizations were carried out at different pumping rates or reaction times with a constant ratio of monomer to initiator. The stoichiometry of the reactants was also adjusted by varying relative flow rates to change the reactant concentrations.
16.
Wojciech Jakubowski Jean‐Franois Lutz Stanislaw Slomkowski Krzysztof Matyjaszewski 《Journal of polymer science. Part A, Polymer chemistry》2005,43(7):1498-1510
Atom transfer radical polymerization (ATRP) and ring‐opening polymerization (ROP) were combined to synthesize poly(?‐caprolactone‐co‐octadecyl methacrylate‐co‐dimethylaminoethyl methacrylate) copolymers possessing a triblock or random block structure. Various synthetic pathways (sequential or simultaneous approaches) were investigated for the synthesis of both copolymers. For the preparation of these copolymers, an initiator with dual functionality for ATRP/anionic ring‐opening polymerization, 2‐hydroxyethyl 2‐bromoisobutyrate, was used. Copolymers were prepared with good structural control and low polydispersities (weight‐average molecular weight/number‐average molecular weight < 1.2), but one limitation was identified: the dimethylaminoethyl methacrylate (DMAEMA) block had to be synthesized after the ?‐caprolactone block. ROP could not proceed in the presence of DMAEMA because the complexation of the amine groups in poly(dimethylaminoethyl methacrylate) deactivated tin(II) hexanoate, which was used as a catalyst for ROP. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1498–1510, 2005 相似文献
17.
Summary : The paper provides experimental results about an easy and versatile method to produce amphiphilic block copolymers, block copolymer particles, and even inorganic – polymeric nano-composites via aqueous heterophase polymerization. Special emphasis is placed on the morphology and colloidal properties of some non-ionic di- and triblock copolymer particles with poly(ethylene glycol) of 106 g/mol molecular weight as hydrophilic block as well as di-stimuli-responsive block copolymers containing both a poly(N-isopropyl acrylamide) and a poly(ionic liquid) block. 相似文献
18.
Controlled synthesis of amphiphilic block copolymer nanoparticles in a convenient way is an important and interest topic in polymer science. In this review, three formulations of polymerization-induced self-assembly to in situ synthesize block copolymer nanoparticles are briefly introduced, which perform by reversible addition-fragmentation chain transfer(RAFT) polymerization under heterogeneous conditions, e.g., aqueous emulsion RAFT polymerization, dispersion RAFT polymerization and especially the recently proposed seeded RAFT polymerization. The latest developments in several selected areas on the synthesis of block copolymer nano-assemblies are highlighted. 相似文献
19.
Hitesh Arora Zihui Li Hiroaki Sai Marleen Kamperman Scott C. Warren Ulrich Wiesner 《Macromolecular rapid communications》2010,31(22):1960-1964
Porous metal thin films have high potential for use in applications such as catalysis, electrical contacts, plasmonics, as well as energy storage and conversion. Structuring metal thin films on the nanoscale to generate high surface areas poses an interesting challenge as metals have high surface energy. In this communication, we demonstrate direct access to nanostructured metal nanoparticle hybrid thin films with high nanoparticle loadings through spin coating of a mixture of block copolymer and ligand stabilized platinum and palladium nanoparticles. Plasma cleaning to remove the organics results in a conductive metal thin film. We expect that the methods described here can be generalized to other metals, mixtures of metal nanoparticles, and intermetallics.