Polymer Chemistry
·
2016
·Vol. 7
·期 7
·1468-1474
·
IF 5.687
Ze Zhang,Zi-Bin Tan,Chun-Yan Hong,De-Cheng Wu,Ye-Zi You
Reactions combining two or more multicomponent reactions performed sequentially in a single pot have attracted great interest due to the fact that they enable more step- and time economic conversions of simple starting materials into complex targets. However, so far, no such reaction has been applied in the synthesis of topologically different polymers. Here, we first report a novel strategy combining the sequential multicomponent reaction (MCR) of a primary amine, a thiolactone and an alkene and the multicomponent polymerization (MCP) of an azide, an alkyne and a secondary amine in one-pot for the syntheses of topologically different polymers (linear, hyperbranched, core–shell polymers). This strategy provides an effective method that can control the sequence and topology of the obtained polymers simultaneously.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
ADVANCES IN POLYMER TECHNOLOGY
·
2021
·Vol. 2021
·期 1
·2966920
·
IF 2.389
Min Qiu,Liang Xiang,Minjing Shang,Yuanhai Su
Microreactors are a promising platform for continuous synthesis of polymer latices when combined with emulsion polymerization. However, this application has long been haunted by fouling and clogging problems. In this work, we proposed the strategy of conducting differential microemulsion polymerization in microreactors within a biphasic slug flow and achieved rapid and stable preparation of nanosized PMMA latices (polymeric content as high as 15.7% with average particle size smaller than 20 nm). We started by exploring the temperature thresholds with thermal and redox initiation, the effect of initiator concentration, and the kinetic characteristics of microemulsion polymerization at different temperatures. Then, as for the differential microemulsion polymerization, extensive investigation was made into the effects of the volumetric flow ratio, the prepolymerization time, the initiator concentration, and the solid content of the initial microemulsion. Finally, we compared the differential microemulsion polymerization with the soap-free emulsion polymerization in the slug flow. The striking advantages in the polymerization rate, the average particle diameter, and the size distribution reflected higher density of particle nuclei, larger specific surface area of particles, and the pivotal effect of the persistent particle nucleation in the microemulsion polymerization.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
ACS Applied Polymer Materials
·
2021
·
IF 4.089
Jian Sun,Chang Wang,Yu-Lin Hong,Zhi-Wei Tan,Cheng-Mei Liu
Reactive polymers with two or more reactive groups in each repeat unit were less reported, and these kinds of polymers were regarded as useful precursors for further multifunctionalization. Here, an alkali-soluble polymer with the bis(hydroxymethyl)phosphine oxide pendant group was first prepared by reversible addition–fragmentation transfer (RAFT) polymerization from a phosphine-containing monomer, namely (4-vinylbenzyl)-bis-hydroxymethyl phosphine oxide (VBzBHPO). The well-defined homopolymers were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and gel permeation chromatography. The molecular weights of both homopolymers and block polymers can be designed by changing RAFT polymerization parameters while still maintaining the narrow molecular weight distributions (mostly Mw/Mn < 1.2). The linear polymerization kinetics and successful chain extension polymerization with styrene or VBzBHPO confirmed the features of controlled/living radical polymerization. Attractively, the resulting polyVBzBHPO showed high solubility in alkaline solution but only lightly swelled in pure water. Such a distinguishing feature of the polymer material provided the possibility of carrying out post-polymerization modification in water with high functionality density and high modification efficiency.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2025
·
IF 2.5
Qingqing Wu,Hujun Shen,Mingsen Deng,Congcong Hao
The development of effective photoinitiators for LED polymerization is still an emerging challenge. Two pull-push conjugate chalcone derivatives were designed and synthesized as the photonitiators for free radical polymerization. (E)-2-(Benzo[d]thiazol-2-yl)-3-(4-((E)-3-(4-(dimethylamino)phenyl)-3-oxoprop-1-en-1-yl) phenyl)acrylonitrile (DMAP-CN) and (E)-3-(4-bromophenyl)-1-(4-(dimethylamino) phenyl)prop-2-en-1-one (BDMAP) were synthesized and used as photoinitiators. The photopolymerization kinetics results demonstrated DMAP-CN and BDMAP could initiate polymerization of HDDA in both one-component and two-component photoinitiating systems. But DMAP-CN exhibited less reactivity than the BDMAP systems on free radical polymerization. To explain the photoinitiating mechanisms, we used different complementary techniques including real-time Fourier transform infrared spectroscopy, UV-visible absorption spectroscopy, fluorescence spectroscopy, cyclic voltammetry, electron paramagnetic resonance spin trapping (EPR-ST) experiments and molecular modelling calculations.
研究领域:
材料科学
·
化学工程
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2010
·
IF 3.573
Jianbo Li,Jie Ren,Yang Cao,Weizhong Yuan
Biodegradable star-shaped poly( ɛ -caprolactone) and poly( ɛ -caprolactone- b - l -lactide) (5sPCL- b -PLLA) with five arms were synthesized by ring-opening polymerization (ROP) from an asymmetric BIS-TRIS core via “core-first” strategy. Subsequently, a series of amphiphilic and double responsive star-block copolymers were synthesized by Z -RAFT star polymerization of N , N -dimethylamino-2-ethyl methacrylate (DMAEMA) from the star-shaped macro-RAFT agent, which was prepared by attaching 3-benzylsulfanylthiocarbonylthiocarbonylsufanylpropionic acid (BSPA) to 5sPCL- b -PLLA using a simple two-step reaction sequence. GPC and 1 H NMR data demonstrated the polymerization courses are under control. The molecular weight of 5sPCL- b -PLLA- b -DMAEMA increased with the monomer conversion, and the molecular weight distribution was in the range of 1.19–1.37. The spherical micelles with degradable core and pH/thermo-double sensitive shell had been prepared from the aqueous medium of the amphiphilic star-shaped copolymers by dialysis method. Both pH and thermal-responsive behaviours of copolymer micelles obtained in this study were investigated. The micelle size and morphology were measured by DLS, AFM and TEM .
研究领域:
高分子化学
·
材料科学
·
纳米医学
✓ 已验证
DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
·
2020
·
IF 4.469
Xiaoyu Ma,Ding Cao,Xiaotong Hu,Jun Nie,Tao Wang
Novel photoinitiators (α-DKs) bearing α-dicarbonyl groups as initiating group and aromatic groups as chromophore group were synthesized and developed as visible light type I photoinitiators with high performance for radical photopolymerization of acrylate. α-DKs exhibit good absorption at 405 nm and higher initiation efficiency compared with commercial initiator camphorquinone (CQ) under LED sources. Meanwhile, α-DKs were found to efficiently photosensitize bis (4-methylphenyl) hexafluorophosphate (ION) and initiate both free radical polymerization and cationic polymerization.
研究领域:
材料化学
·
光化学
✓ 已验证
DOI
高影响因子
POLYMER JOURNAL
·
2020
·Vol. 52
·期 12
·1323-1331
·
IF 2.826
Xia Lei,Zhang Ze,You Ye-Zi
Ring-opening polymerization of lactones has served as one of the most resourceful and versatile methods for the production of polyesters. However, the photocontrolled ring-opening polymerization of lactones with the advantages of being inexpensive, green, and noninvasive, is still rarely reported. In this work, we developed a series of composite photoacid generators containing a common photocatalyst and an onium salt to induce the living/controlled cationic ring-opening polymerization of lactones using benzyl alcohol or butyl alcohol as an initiator under visible light. The wavelength of the light could be easily adjustable by applying different photocatalysts. Moreover, radical species are generated concurrently during the electron transfer processes; as a result, simultaneous living/controlled cationic ring-opening polymerization of lactones and reversible addition–fragmentation chain transfer radical (RAFT) polymerization can be performed using hydroxy group capped trithiocarbonate to produce hybrid block copolymers.
研究领域:
高分子化学
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材料科学
✓ 已验证
DOI
高影响因子
MACROMOLECULAR RESEARCH
·
2021
·Vol. 29
·期 7
·477-486
·
IF 2.227
Xue Yang,Li Xiaohua,Zhang Shixian,Guo Ruiwei
Chain transfer reactions are important side reactions in the radical polymerization of acrylates. Discrimination between interchain and intrachain transfer is still a challenge for the study of interchain transfer. A prepolymer, poly(benzyl acrylate) with hydroxy terminals (HO-PBzA), was designed and used in the reversible addition-fragmentation chain transfer (RAFT) polymerization of BzA to measure the interchain transfer degree, with benzyl N -carbazole dithiocarbamate (BCBD) as the RAFT agent. Liquid chromatography at critical conditions was used to separate and measure interchain transfer products and then BzA interchain transfer constants ( C tr ) at different temperatures determined without other kinetic parameters. Experimental results showed that experimental parameters in RAFT polymerization, except the high dosage of BCBD, had no significant effects on the measured C tr , which showed good repeatability. The C tr of benzyl acrylate at 100–120 °C was in the order of 1−2×10 −4 and the activation energy of C tr was at 31.1 kJ·mol −1 .
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2021
·
IF 4.43
Zhengyuan Zhang,Yu Liu,Xiaochuan Shui,Youqing Yu,Chunyan Zheng,Yuechuan Wang
It is still a challenge to directly, without any control means, synthesize polymers bearing acetylene groups by normal free radical polymerization (FRP) of acetylenyl vinyl monomers , such as propargyl (meth)acrylates, because the reactive acetylene groups result in chain branching and gelation . Some propargyl acrylates with alkyl substitutes, however, can afford linear and soluble polymers. To clarify the substitute effects the FRP behaviours of a series of acrylates bearing acetylene groups with or without substitutes are studied. Homopolymerizations of acetylenyl acrylates without or with mono-substitute on propargyl led to branched polymers at early reaction stage, and became gelled after 0.5 h with monomer conversion over 12% and gel content over 50%. The acetylenyl acrylates with di-substitutes on propargyl can afford linear and soluble homo- and copolymers with‾M n up to over 10,000 and with 45–75% monomer conversion, except for monomer 2-(2-methylbut-3-yn-2-yloxy)ethyl acrylate (DMPOEA) which has di-substitutes and a spacer connecting to the propargyl. Reactivities of vinyl and acetylene groups were found within 20 times difference by laser flash photolysis (LFP) experiments. The substitute effects of acetylenyl acrylates on FRP are explained by the intramolecular cycloaddition between C C and C C to form lactone from the s-cis conformers of the di-alkyl substituted acetylenyl acrylates. Propagating radicals can transform to stable allyl radicals by α-H atom transfer and thus the chain propagations stop. Both real-time FT-IR monitoring of photo-polymerization and high resolution 13 C NMR spectra of the polymer confirmed the existence of lactone units on polymer chains. The hypothesis is also accordance with facts obsorved in the FRP. Finally postpolymerization modification through acetylene groups on polymer chains by photo thiol-yne click reaction is exemplified.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2018
·
IF 3.483
Chujuan Huang,Nobuko Yamashita,Amorn Chaiyasat,Xiang Liu,Masayoshi Okubo
Microsuspension conventional radical polymerization ( ms CRP) of methyl acrylate (MA), which is more hydrophilic monomer than methyl methacrylate (MMA), was carried out at different benzoyl peroxide (BPO) concentrations (0.8–8.0 wt% relative to MA), gave not similar micrometer-size poly(MA) (PMA) particles as MA droplets but submicrometer-size ones. That is, emulsion polymerization proceeded in the ms CRP systems. When microsuspension iodine transfer polymerization ( ms ITP) with CHI 3 as chain transfer agent was carried out at 8.0 wt% BPO (relative to MA), at which micrometer-size poly(MMA) particles were successfully synthesized without submicrometer-size byproduct particles in a previous particle, only submicrometer-size PMA particles were formed, too. However, the percentage of the byproduct particles obviously decreased with a decrease in the BPO concentration, resulting in zero practically at 0.8 wt% BPO, where number-average molecular weight of the micrometer-size PMA particles was nearly equal to theoretical one and polydispersity was comparatively narrow ( M w / M n = 1.43). Such experimental results were presumed based on the kinetic simulation study. Above results support the validity of the “radical exit depression (RED) effect” proposed and indicate a decisive effectiveness of ms ITP to improve a long-standing problem of ms CRP of “hydrophilic” monomer.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2014
·Vol. 5
·期 14
·4277-4284
·
IF 5.368
Xueteng Cao,Chunlei Zhang,Songbai Wu,Zesheng An
We have developed a highly efficient, one-step approach for the synthesis of core cross-linked star (CCS) polymers using commercial macromonomers (polyethylene glycol methyl ether methacrylates) as the arms via RAFT-mediated emulsion polymerization in aqueous media. This approach employs a small molecular chain transfer agent (CTA), commercial macromonomer, hydrophobic cross-linker, and optional hydrophobic spacing monomer as the polymerization recipe to synthesize CCS polymers via direct one-step polymerization in aqueous buffer solution. Various polymerization parameters, including buffer concentration and molar ratio of macromonomer/cross-linker/spacing monomer relative to CTA, were investigated. CCS polymers of high yield and low dispersity were obtained within 4 h under a wide range of conditions. Analysis of polymerization kinetics and macromolecular parameters of the generated polymeric species during the polymerization process led to insights into the mechanistic aspects of the CCS formation process, which was proposed to involve three stages, i.e., polymer chain growth, cross-linking to form CCS, and CCS growth. Finally, synthesis of CCS polymers using macromonomers of different molecular weights pointed to the necessity for optimization of the polymerization conditions for each macromonomer, possibly due to different polymerization rates and steric hindrance.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2015
·
IF 5.8
Huajun Huang,Yunbin Yuan,Jianping Deng
Optically active polymer particles constitute a unique type of polymer particle. However, nearly all the particles of this kind so far reported in the literature were prepared from chiral monomers. On the other hand, helix-sense-selective polymerization (HSSP) techniques were majorly applied in solution polymerization systems for preparing helical polymers adopting predominant one-handed helicity. In the present study, we report the first HSSP in precipitation polymerization systems, by which optically active helical polymer particles were constructed from an achiral monomer. Achiral acetylenic monomer with bulky adamantyl group smoothly underwent helix-sense-selective precipitation polymerization (HSSPP) with (nbd)Rh+B–(C6H5)4 as catalyst in the presence of Boc-l- or Boc-d-alanine as chiral additive. The HSSPPs provided optically active polymer particles consisting of helical polymer forming predominantly one-handed screw sense. SEM images show that the resulting polymer particles were obtained in high yield (80 wt %, average diameter approximately 300 nm) with regular spherical morphology. CD spectra clearly demonstrated that HSSP occurred in the course of precipitation polymerizations. The induced helical structures with preferential screw sense exhibited relatively high thermostability. We further proposed a possible mechanism for the occurrence of HSSPPs and the formation of stable helical structures: Double hydrogen bonds formed between each chiral additive molecule and the neighboring two amide structures in the polymer pendant groups; the double hydrogen bonds played essential roles for controlling the screw sense of the helical polymer chains and the stability. Based on this mechanism, a “chiral-lock effect” was further put forward. The preparative strategy opens new routes for preparing optically active polymer particles and even novel superhelical architectures for significant uses as chiral stationary phase for HPLC, chiral catalysts, enantioselective recognition probes, etc.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）