JOURNAL OF APPLIED POLYMER SCIENCE
·
2015
·Vol. 132
·期 25
·
IF 1.768
Xiao-Hui Liu,Fei-Jun Zhang,Hui-Na Li,Xiao-Hui Hu,Wen-Li Di,Shuang Zhao
A facile, safe, and inexpensive reducing agent, sodium hypophosphite (NaH 2 PO 2 ·H 2 O), has been successfully used to perform ambient temperature living radical polymerizations of methyl methacrylate (MMA) and styrene (St). The rapid radical polymerizations were readily obtained at 25°C, i.e., MMA reached a conversion of ca 90% after 2.5 h, and St reached a conversion of ca 80% after 40 h. The polymerizations of MMA and St exhibited excellent living/controlled nature, as evidenced by pseudo first-order kinetics of polymerization, linear evolution of molecular weights with increasing monomer conversions, and narrow molecular weight distributions. The various experimental parameters—ligand, solvent, and molar ratio of NaH 2 PO 2 ·H 2 O to CuSO 4 ·5H 2 O—were varied to improve the control of polymerization, molecular weight, and molecular weight distribution. 1 H NMR analyses and chain-extension reactions confirm the high chain-end functionality of the resultant poly(methyl methacrylate) and polystyrene. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42123.
研究领域:
高分子化学
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聚合反应工程
·
功能高分子材料
·
可控/活性聚合
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绿色合成方法
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 27
·22908-22916
·
IF 3.289
Jianwen Tian,Xiaohui He,Jingyin Liu,Xiaodan Deng,Defu Chen
Palladium(II) and copper(II) chloride complexes bearing bulky 9,10-dihydro-9,10-ethanoanthracene-11,12-diimine ligands were synthesized and sufficiently characterized by elemental and spectroscopic analysis along with X-ray diffraction analysis. The X-ray diffraction demonstrated that palladium(II) complexes (C1–C2) and copper(II) complexes (C3–C4) were four-coordinated. All these complexes displayed catalytic activities up to 105 gpolymer molMt−1 h−1 for norbornene vinyl-addition polymerization on treatment with excess methylaluminoxane (MAO). The parameters of the reaction conditions, the type of metals and steric effects of coordinative ligands had influences on the catalytic properties. C2 was selected as a catalyst precursor for the copolymerization of norbornene (NB) with 2-butyloxymethylene norbornene (BN), which exhibited catalytic activities up to 1.1 × 105 gpolymer molPd−1 h−1 and produced copolymers with relatively high molecular weights. The fraction of BN in the copolymer could reach up to 9.8–62.1% by controlling the monomer feed ratio range from 10–80%. The achieved vinyl-addition type poly(NB-co-BN) displayed high thermal stability and was soluble in common organic solvents, such as CHCl3 and THF.
研究领域:
高分子化学
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配位化学
·
催化化学
·
有机金属化学
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功能高分子材料
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Zhanwei Yang,Jin Wang,Hualei Chen,Hecheng Meng,Xiaobing Guo,Shujuan Yu
Two low-methoxy pectins (LMPs) were obtained by local electrochemical pH modification using an H-type double-layer water bath sealed electrochemical cell at the voltage of 180 V for 3 h. The weight-average molecular weight (Mw) of citrus peel pectin (CPP) prepared in the anodic part at room temperature (CPP-A 5/RT ) and in the cathodic part at 5 °C (CPP-C 5/RT ) were 346 kDa and 328 kDa, respectively, and the degrees of methylation (DM) were 36.8 % and 11.9 %. Moreover, the second-order kinetic model was most appropriate for the degradation processes, as free radicals were generated in the anodic part and β -elimination occurred in the cathodic part. Subsequently, CPP-A 5/RT and CPP-C 5/RT were utilized to fabricate food packaging film blending with polyvinyl alcohol (PVA), bcZnO (ZnO coupled with bentonite and colophony) nanorods , and Ca 2+ ions by casting method. Then the prepared films were studied for their ability to maintain the freshness of strawberries. The addition of Ca 2+ ions and bcZnO nanorods increased the thickness, water contact angle (WCA), and mechanical properties of the composite films, while decreased water vapor permeability (WVP). Therefore, the CPP-based films, supplemented with bcZnO nanorods and crosslinked with Ca 2+ ions by “egg-box” model, can serve as an antibacterial food packaging material for food preservation.
研究领域:
食品科学
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高分子材料
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食品包装
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电化学改性
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纳米复合材料
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农产品保鲜
✓ 已验证
DOI
高影响因子
POLYMER
·
2019
·
IF 3.771
Feng Chen,Ziqing Tang,Shaoping Lu,Lin Zhu,Qilin Wang,Qin Gang,Jia Yang,Qiang Chen
Double network hydrogels (DN gels) are one of most extensively investigated high strength hydrogels. However, most of DN gels are concern to macromolecules , low-molecular-weight gelators (LMWG)-based supramolecular hydrogels are rarely reported to fabricate recoverable DN gels. Owing to the low mechanical properties, LMWG-based supramolecular hydrogels are hardly fabricated as conductive materials for human motion monitoring. Herein, we report a general strategy to fabricate strong, tough and conductive cholate-based supramolecular gels with double network (DN) structure (i.e. La-cholate/PAAm DN gels), consisting of La-cholate supramolecular gel as first network and covalent polyacrylamide gel (PAAm gel) as second network, in which La-cholate supramolecular gel was self-assembled by La 3+ ions and sodium cholate under sonication via the synergistic effect of hydrogen bonds , hydrophobic interactions and metal-coordination. At optimal condition, La-cholate/PAAm DN gel exhibited high tensile properties (fracture stress of 0.314 MPa, fracture strain of 29.85 mm/mm, elastic modulus of 90 kPa, and work of extension of 5.678 MJ/m 3 ) and high toughness (tearing energy of 1098 J/m 2 ), which are comparable to conventional chemical or hybrid DN gels. Meanwhile, La-cholate/PAAm DN gel also showed rapid self-recovery property (stiffness recovery of 84% and toughness recovery of 46% after resting for 3 min) at room temperature and λ-dependent luminescent property under UV-light. More importantly, cholate-based supramolecular gels with DN structure could be prepared with various metal ions and monomers . Interestingly, our cholate-based DN gels were ionically conductive, which could be used as strain sensor to finely detect the human motions. We hope our design principles, along with the simple method and cholate-based DN gels, can be generally applied to develop a new generation of strong and tough LMWG-based supramolecular hydrogels with various functionalities.
研究领域:
高分子科学
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生物材料
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软物质物理
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纳米医学
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组织工程
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智能响应材料
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生物传感
✓ 已验证
DOI
高影响因子
RSC Advances
·
2022
·Vol. 12
·期 19
·11715-11721
·
IF 4.036
Baokang Zou,Yipeng Zhan,Xiuli Xie,TongTong Zhang,Runkai Qiu,Fangming Zhu
Two salalen titanium(IV) complexes ((H-salalen)TiCl2 and (F-salalen)TiCl2) containing hydrogen and fluorine respectively on the phenolate ring close to the imine were synthesized for the copolymerization of ethylene with 1-octene to prepare poly(ethylene-co-1-octene) in the presence of methylaluminoxane (MAO). The (F-salalen)TiCl2/MAO showed higher catalytic activity and better copolymer characteristics such as a higher molecular weight, narrower molecular weight distribution, and higher 1-octene incorporation than (H-salalen)TiCl2/MAO, which revealed that the electron-withdrawing conjugated effect introduced by fluorine substituents led to improvements on catalytic performance and thermal stability. The influences of copolymerization conditions including temperature, Al/Ti molar ratios and comonomer feed ratios on the copolymerization behavior of (F-salalen)TiCl2/MAO and the copolymer microstructure were investigated in detail. Under the activation of MAO, the (F-salalen)TiCl2 could produce ultrahigh molecular weight poly(ethylene-co-1-octene) with 1-octene incorporation ratios in the range of 0.9–3.1 mol% and exhibit relatively high activity. It could be inferred that long ethylene sequences in the copolymer were segregated by the isolated 1-octene units based on the 13C NMR characterization of the copolymer. Moreover, the thermal properties and crystallization of copolymers were determined by DSC and XRD and correlated to the ethylene sequence length distribution. The reactivity ratios calculated by the triad distribution in 13C NMR revealed the random comonomer distribution in the copolymer chain.
研究领域:
高分子化学
·
配位聚合
·
催化化学
·
材料科学
·
高分子物理
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2012
·Vol. 50
·期 24
·5177-5184
·
IF 3.919
Yonggang Gao,Lin Gu,Yusheng Qin,Xianhong Wang,Fosong Wang
Low-molecular weight oligo(carbonate-ether) diols are important raw materials for polyurethane formation, which with tunable carbonate unit content (CU) may endow new thermal and mechanical performances to polyurethane. Herein, facile synthesis of oligo(carbonate-ether) diols with number average molecular weight ( M n ) below 2000 g mol −1 and CU tunable between 40% and 75% are realized in high activity by immortal copolymerization of CO 2 /propylene oxide (PO) using zinc-cobalt double metal cyanide complex (Zn-Co-DMCC) in the presence of sebacic acid (SA). M n of the oligomer is in good linear relationship to the mole ratio of PO and SA (PO/SA) and hence can be precisely controlled by adjusting PO/SA. Besides, the molecular weight distribution is quite narrow due to the rapid reversible chain transfer in the immortal copolymerization. High pressure and low temperature are favorable for raising CU. In all the reactions, the weight fraction of propylene carbonate ( W PC ) can even be controlled as low as 2.0 wt %, and the catalytic activity of Zn-Co-DMCC is above 1.0 kgg −1 cat. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
研究领域:
高分子化学
·
催化化学
·
绿色化学
·
功能材料
·
聚合物合成
·
二氧化碳利用
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）