Polymers
·
2020
·Vol. 12
·期 10
·2305
·
IF 3.426
Dan Tian,Ji-Huan He
Mechanical property is one of the most important properties of nanofiber membranes. Electrospinning is widely used in the preparation of nanofibers due to its advantages such as good stability and easy operation. Compared with some nature silk, the mechanical properties of nanofibers prepared by electrospinning are poor. Based on the principle of vortex spinning and DNA structure, this paper designed an air vortex electrospinning device that can control the structure of macromolecular chains in nanofibers. When a weak air vortex is generated in the electrospinning process, the macromolecule chains will entangle with each other and form a DNA-like structure so as to improve the mechanical property. In addition, when a strong air vortex is generated during the electrospinning process, the nanofibers will adhere to each other, thereby enhancing the mechanical property and enlarging the pore size.
研究领域:
材料科学
·
生物工程
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DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2024
·
IF 5.8
Lingshan Li,Qian Zhou,Jingyi Zhao,Yuangong Zhang,Zhaolei Jia,Xuan Liu,Hailei Zhang,Xinwu Ba,Libin Bai
Multiblock copolymer macrochain-transfer agents (MBP-CTAs) can be used to synthesize MBPs in one pot via reversible addition-fragmentation chain-transfer (RAFT) polymerization. MBP-CTAs can be efficiently synthesized via a copper-catalyzed azide-alkyne cycloaddition reaction. However, traditional purification methods cannot sufficiently purify MBP-CTAs, resulting in the failure of RAFT. In this study, it was discovered that using a supported catalytic system, namely, Cu@A-HNTs, inhibited the connection between Cu and S. The residual Cu content in the MBP-CTA was successfully reduced to a low level (7.88 µg/mg). Then, hydrophilic and hydrophobic MBPs were synthesized through RAFT polymerization using the MBP-CTAs. Subsequently, multiblock copoly(methyl methacrylate-b-butyl methacrylate-CTA)s (PMMA-b-PBMA-c-CTA)s were successfully prepared. The MBP-CTAs and MBPs were characterized using ultraviolet–visible spectroscopy, 1 H nuclear magnetic resonance, size-exclusion chromatography, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, differential scanning calorimetry measurements and uniaxial tensile tests. The results of performance testing of PMMA-b-PBMA-c-CTAs demonstrated that their fracture stress and strain significantly increased comparing with that of PMMA-b-CTAs.
研究领域:
高分子化学
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材料科学
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产品关联
DOI
高影响因子
POLYMER JOURNAL
·
2023
·Vol. 55
·期 11
·1129-1139
·
IF 2.8
Wang Shuai,Li Gang,Liu Zhongguo,Yang Ze,He Jinlin,Dong Xue-Hui
Rational design of “giant” building blocks promotes the modular construction of polymeric counterparts at a large length scale. In this study, a series of biscylooctyne- and bisazide-functionalized polyhedral oligomeric silsesquioxane (POSS) monomers with different regio-configurations were synthesized. Homo and alternating giant polymeric chains were then efficiently prepared by strain-promoted azide-alkyne cycloaddition (SPAAC) polymerization. The obtained monomers and polymers were characterized by proton nuclear magnetic resonance ( 1 H NMR), size exclusion chromatography (SEC), and matrix-assisted laser desorption ionization time-of-flight (MALDI-ToF) mass spectrometry. The influence of the feeding ratio, monomer concentration, and regio-configuration on the step-growth polymerization was investigated. Due to the large monomer size, the giant chains can be purified and fractionated by preparative SEC. This work provides a facile and efficient approach for the modular construction of main-chain polymers with nanosized building blocks.
研究领域:
材料科学
·
有机化学
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DOI
高影响因子
POLYMER
·
2024
·
IF 4.1
Haidi Wu,Yongchuan Wu,Jun Yan,Yuqing Wang,Hechuan Zhang,Zhanqi Liu,Huamin Li,Junjie Wang,Jiefeng Gao
Despite the unique properties, the hydrogels’ weak mechanical properties have severely limited their practical applications, and it remains great challenging to simultaneously enhance the strength , toughness and fracture energy of hydrogels. Herein, we develop strong yet tough polyvinyl alcohol (PVA) hydrogels via the synergy of wet-annealing and Hofmeister effect. The macromolecular chain engineered multiscale strengthening and toughening are achieved. The densified polymeric network, increased crystallinity and enhanced hydrogen bonding interaction enables the PVA hydrogels to have outstanding mechanical properties. The tensile strength , toughness and fracture energy of the resultant hydrogels can reach as high as 21.4 MPa, 182.3 MJ/m 3 and 56.8 kJ/m 2 , respectively. This study provides a new avenue to effectively tune the macromolecular chain conformation and hence improve the comprehensive mechanical properties of gel materials.
研究领域:
材料科学
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高分子化学
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机械工程
✓ 已验证
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 9
·1440
·
IF 3.164
Dan Lu,Hu Wang,Ru-Ke Bai
An alternating fluorinated copolymer based on chlorotrifluoroethylene (CTFE) and butyl vinyl ether (BVE) was synthesized by RAFT/MADIX living/controlled polymerization in the presence of S-benzyl O-ethyl dithiocarbonate (BEDTC). Then, using the obtained poly(CTFE-alt-BVE) as a macro chain transfer agent (macro-CTA), a block copolymer was prepared by chain extension polymerization of vinyl acetate (VAc). After a basic methanolysis process, the poly(vinyl acetate) (PVAc) block was transferred into poly(vinyl alcohol) (PVA). Finally, a novel fluorinated polyurethane with good surface properties due to the mobility of the flexible fluorinated polymer chains linked to the network was obtained via reaction of the copolymer bearing the blocks of PVA with isophorone diisocyanate (IPDI) as a cross-linking agent.Keywords:fluorinated polyurethane;fluorinated polymer;chlorotrifluoroethylene
研究领域:
高分子化学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2023
·Vol. 41
·期 12
·1856-1867
·
IF 4.3
Zhang Yan-Xin,Chen Dong,Hu Gao-Fei,Ma Yu-Hong,Yang Wan-Tai
The alternating copolymerization of hydroxyalkyl vinyl ethers and dialkyl maleates is investigated by conventional radical polymerization and reversible addition-fragmentation chain transfer polymerization (RAFT). The influence of comonomer structure, comonomer feeding ratios, and monomer concentrations on the copolymerization and the copolymer structure have been investigated systematically. With 2-hydroxyethyl vinyl ether (HEVE) and dimethyl maleates (DMM) as comonomers, a well-defined alternating copolymer is prepared with M n =3400 and M w / M n =1.93 up to 71.6% monomer. The alternating sequential chain structure of the copolymers has been proved by both NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The experimental reactivity ratios and theoretical calculated highest occupied molecular orbital and the lowest unoccupied molecular orbital of vinyl ethers and alkyl maleates support that these monomer pairs have tendency to form alternating copolymers. With 2-cyanopropan-2-yl N -methyl- N -(pyridin-4-yl)carbamodithioate as the RAFT agent, the molecular weight of HEVE and DMM copolymer increases with the monomer conversion, demonstrating a controlled radical polymerization feature with well-controlled molecular weight and relatively narrower molecular weight distribution. With alternating copolymer of HEVE and DMM as macro-CTA ( M n =5200 and M w / M n =1.46), both the chain extension with HEVE and DMM ( M n =10400 and M w / M n =1.72) and block copolymerization with vinyl acetate have been successfully achieved ( M n =8500 and M w / M n =1.52).
研究领域:
高分子化学
·
材料科学
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产品关联
DOI
高影响因子
TALANTA
·
2021
·
IF 6.057
Yicheng Wang,Dongliang Yang,Yaqin Hu,Yuxin Wang,Wen Jing Yang,Lianhui Wang
Lanthanide nanoprobes have attracted extensive attention for applications in cellular imaging and biological sensing. Herein, water-dispersible europium (III)-based (Eu(III)-based) nanoprobes were prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization-induced self-assembly (PISA) of hydrophobic monomers (Eu(III)-containing monomer and methyl methacrylate (MMA)) using hydrophilic macro-chain transfer agent poly(PEGMA)-CTA. The resulted poly(PMEu) nanoprobes showed spherical in shape in good monodispersity with average diameters of around 210 nm. The poly(PMEu) nanoprobles excellent aqueous dispersity, high aqueous stability and good luminescence properties with quantum yields of 37.21% and fluorescence lifetime of 312.4 μs. Moreover, the poly(PMEu) nanoprobes exhibited good cellular biocompatibility with cell viabilities of 88.2% and high fluorescence intensity for in vitro cellular imaging. The present approach provides a facile strategy for fabrication of luminescent Eu(III)-based nanoprobes with great potential applications for biological imaging.
研究领域:
材料科学
·
纳米技术
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生物医学工程
·
细胞生物学
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产品关联
DOI
PubMed
高影响因子
Polymer Chemistry
·
2014
·Vol. 5
·期 21
·6244-6255
·
IF 5.368
Yuanyuan Xu,Youcheng Li,Xueteng Cao,Qijing Chen,Zesheng An
Reversible addition–fragmentation chain transfer (RAFT) dispersion polymerization in cononsolvents of poly(N-isopropylacrylamide) (PNIPAM) was developed as a versatile strategy for the synthesis of thermoresponsive nanogels with controlled composition, functionality and architecture. Cononsolvents composed of mixtures of methanol, ethanol and isopropanol with water were first screened for their suitability as the media for dispersion polymerization of NIPAM, and water–ethanol (75 : 25, v : v) solution was selected due to good RAFT control, efficient formation of nanogels and low toxicity. RAFT dispersion polymerization of NIPAM in the cononsolvent using poly(N,N-dimethylacrylamide) (PDMA) as the macromolecular chain transfer agent (Macro-CTA) showed good control over the molecular weight, polydispersity and pseudo linear polymerization kinetics, as characterized by gel permeation chromatography (GPC) and 1H NMR. The effect of the molecular weight of Macro-CTA, the degree of polymerization of PNIPAM, the molar ratio of [crosslinker] : [Macro-CTA] and the solid content on the formation and size of nanogels was investigated. The thermal profiles of nanogels were characterized by dynamic light scattering (DLS) both in cononsolvents and water. This cononsolvency strategy for dispersion polymerization was shown to be compatible with the incorporation of hydrophilic comonomers of N-(2-hydroxyethyl)acrylamide (HEAM) and diacetone acrylamide (DAAM). The nanogel containing DAAM was demonstrated for postpolymerization modification using ketone–alkoxyamine chemistry. More importantly, dispersion polymerization in cononsolvents allowed various hydrophobic components, e.g. butyl acrylate (BA), fluorescein O-acrylate (FLA), and 1,6-hexanediol diacrylate (HDDA), to be reliably copolymerized with NIPAM, showing well controlled polymerization, composition, nanogel size and colloidal stability. Finally, an amphiphilic block copolymer PDMA-b-PBA was used as a Macro-CTA to produce the PDMA-b-PBA-b-PNIPAM triblock copolymer and triple-layered nanogel, taking advantage of the solubility of PDMA-b-PBA and the insolubility of PNIPAM in the water–ethanol solution at the polymerization temperature.
研究领域:
高分子化学
·
材料科学
·
纳米技术
✓ 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）