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微反应器技术在聚合中的应用研究进展
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作者 袁炜 刘卫卫 +2 位作者 李倩 李化毅 胡友良 《高分子通报》 CAS CSCD 北大核心 2019年第1期94-101,共8页
微反应器因其优良的传热、传质性能在聚合反应中的研究方兴未艾。与传统釜式聚合相比,微反应器聚合能够更好地调控聚合物分子量分布,提高聚合反应速率,控制聚合物分子结构和产物形貌。本文综述了微反应器技术在配位聚合、开环聚合和光... 微反应器因其优良的传热、传质性能在聚合反应中的研究方兴未艾。与传统釜式聚合相比,微反应器聚合能够更好地调控聚合物分子量分布,提高聚合反应速率,控制聚合物分子结构和产物形貌。本文综述了微反应器技术在配位聚合、开环聚合和光诱导可控自由基聚合中的研究进展,并简要介绍了微反应器聚合技术的放大实验。最后,对微反应器技术在聚合物合成中的发展方向提出展望。 展开更多
关键词 微反应器 聚合反应 配位聚合 开环聚合 光诱导可控自由基聚合
A User-friendly Living Cationic Polymerization: Degenerative Chaintransfer Polymerization of Vinyl Ethers by Simply Using Mixtures of Weak and Superstrong Protonic Acids
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作者 Mineto Uchiyama Masataka Sakaguchi +1 位作者 Kotaro Satoh Masami Kamigaito 《高分子科学:英文版》 SCIE CAS CSCD 2019年第9期851-857,共7页
Mixtures of a weak protonic acid and a trace amount of superstrong protonic acid were used for the simple control of the cationic polymerization of vinyl ethers via a degenerative chain-transfer mechanism, in which th... Mixtures of a weak protonic acid and a trace amount of superstrong protonic acid were used for the simple control of the cationic polymerization of vinyl ethers via a degenerative chain-transfer mechanism, in which the former acid works as a precursor of the chain transfer agent (CTA) or the dormant species and the latter works as a source of the cationic propagating species. The addition of mixtures of phosphoric acid dibutyl ester ((n=BuO)2PO2H) or 1 -octanethiol (n-C8H17SH) and a trace amount of trifluoromethanesulfonic acid (TfOH) to a solution of isobutyl vinyl ether (IBVE) at -78℃ resulted in polymers with controlled molecular weights, which were basically determined by the feed ratio of IBVE to the weak protonic acid, and narrow molecular weight distributions (Mw/Mn≈ 1.1). These results were almost the same as those obtained using their prepared adducts of IBVE as CT As in the presence of a trace amount of TfOH under similar conditions. Methanesulfonic acid (CH3SO3H), whose adduct of IBVE has not been isolated due to instability, was similarly used in conjunction with trace TfOH to result in controlled molecular weights but slightly broader MWDs (Mw/Mn = 1.2-1.8). These results indicate that the sulfoxonium ion is also an effective intermediate in the cationic DT polymerization in addition to the phosphonium and sulfonium intermediates derived from (n=BuO)2PO2H and C8H17SH, respectively. The simple living cationic polymerization was thus achieved by using a combination of a weak protonic acid and a trace amount of TfOH, which are both easily available, low cost, free from metal, and easy to handle, without need for preparation of the initiator. 展开更多
关键词 Living CATIONIC POLYMERIZATION DEGENERATIVE chain transfer RAFT POLYMERIZATION Metal free VINYL ETHER
Facile Synthesis of Functional Poly(ε-caprolactone) via Janus Polymerization
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作者 Huan Qiu Zhe-Ning Yang Jun Ling 《高分子科学:英文版》 SCIE CAS CSCD 2019年第9期858-865,共8页
Functionalized aliphatic polyesters attract increasing attentions as biocompatible and biodegradable polymers with broad applications in biological science. In this contribution, we propose a facile and controllable s... Functionalized aliphatic polyesters attract increasing attentions as biocompatible and biodegradable polymers with broad applications in biological science. In this contribution, we propose a facile and controllable synthetic technique for functional poly(ε-caprolactone)(PCL) via Janus polymerization, which comprises cationic ring-opening copolymerization (ROP) of ε-caprolactone (CL) with 3,3-bis(chloromethyl)oxacyclobutane (CO) and (coordinated) anionic ROP of CL at a single propagating chain by rare earth metal triflates (RE(OTf)3)and propylene oxide, thus generating block copolymers in one step. The compositions of the copolymers of poly(CLb-(CL-r-CO)) can be modulated by various RE(OTf)3. Scandium triflate catalyzes Janus polymerization to yield the copolymers containing the highest CO contents among all the RE(OTf)3 catalysts used with complete conversion of CL. The chlorine in CO repeating units is ready to be transferred into azide group which affords the modification sites to react with 9-ethynyl-9-fluorenol and mPEG-alkyne, respectively, via copper(I)-catalyzed azide-alkyne cycloaddition reaction with quantitative conversions of azides, as confirmed by FTIR analyses. According to NMR and SEC analyses, copolymers (PCC-g-PEG) bearing a homo-PCL block and a PEG-grafted block of poly(CO-co-CL) demonstrate well-defined chemical structures. The investigations on thermal properties reveal the strong phase separation between PCL and PEG blocks. The amphiphilic PCC-g-PEG is able to sei住assemble into micelles in aqueous solution while cylindrical and lamellar morphologies are observed in bulk. We provide an efficient protocol to synthesize functional PCL combining onestep Janus polymerization and precise post-polymerization click reaction. 展开更多
关键词 JANUS POLYMERIZATION FUNCTIONAL poly(ε-caprolactone) Poly(3 3-bis(chloromethyl)oxacyclobutane) RING-OPENING POLYMERIZATION Rare earth metal CATALYSTS
Mechanism of Janus Polymerization: A DFT Study
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作者 Tian-Wen Bai Xu-Feng Ni +1 位作者 Jun Ling Zhi-Quan Shen 《高分子科学:英文版》 SCIE CAS CSCD 2019年第10期990-994,I0004,共6页
Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxid... Janus polymerization is featured as a combination of cationic and anionic growing ends in one living polymer chain. In the copolymerization of THF and CL catalyzed by lutetium triflates and initiated by propylene oxide, three stages are identified by kinetic study including(1) fast cationic polymerization with slow anionic one,(2) fast anionic polymerization with dormant cationic one, and(3)reactivation of cationic polymerization with coupling of anionic and cationic chain ends. In this work, density functional theory(DFT)calculation is employed to investigate the reaction details of ionic polymerization and dormancy. A “tripedal crow” configuration is proposed to illustrate the unique high-coordinated ligand exchange configuration in anionic polymerization in different stages. The trigger of dormancy is determined as chain structures rather than concentration of triflate anion according to both calculation and experimental results. 展开更多
关键词 Rare earth metal catalysts Ring-opening polymerization Ionic polymerization Reaction mechanism Quantum chemicalcomputation
含辣素功能结构丙烯酸树脂的制备及其在渔网防污涂料中的应用研究
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作者 曹京宜 于良民 +3 位作者 杨延格 赵海洲 张寒露 董磊 《中国涂料》 CAS 2019年第5期25-29,共5页
针对辣素类似物防污剂通过混合加入到防污涂料中释放速度过快的问题,本实验将N-(4-羟基-3-甲氧基)苄基丙烯酰胺(HMBA)通过共聚合的方法引入到丙烯酸树脂中以延长其防污期效。红外吸收光谱表明本研究成功制得了含辣素功能结构的丙烯酸树... 针对辣素类似物防污剂通过混合加入到防污涂料中释放速度过快的问题,本实验将N-(4-羟基-3-甲氧基)苄基丙烯酰胺(HMBA)通过共聚合的方法引入到丙烯酸树脂中以延长其防污期效。红外吸收光谱表明本研究成功制得了含辣素功能结构的丙烯酸树脂。实验发现,HMBA具有一定的阻聚作用;偶氮类引发剂的用量为单体质量的1.3%时所得树脂状态较好。海上实验证明,以上述树脂为成膜物的防污涂料,防污效期可达10个月,其防污性能达到了国外同类产品的技术水平。 展开更多
关键词 防污 辣素 丙烯酸树脂 聚合
聚醋酸乙烯酯的合成及其在超临界二氧化碳中的相行为 预览
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作者 焦真 宋俊颖 +2 位作者 樊文景 王秀东 王梓屹 《东南大学学报:英文版》 EI CAS 2019年第2期264-268,共5页
利用可逆加成断裂链转移自由基聚合法制备了3个具有可控分子量和窄分子量分布的聚醋酸乙烯酯单聚物,并讨论了反应温度和引发剂加入量对聚合过程的影响.然后,通过浊点法测定了相对制得的聚合物在加压的二氧化碳中的相行为.结果表明,聚合... 利用可逆加成断裂链转移自由基聚合法制备了3个具有可控分子量和窄分子量分布的聚醋酸乙烯酯单聚物,并讨论了反应温度和引发剂加入量对聚合过程的影响.然后,通过浊点法测定了相对制得的聚合物在加压的二氧化碳中的相行为.结果表明,聚合物的浊点随着分子量、聚合物浓度和温度的增加而增大,在0.12%的质量浓度和35℃温度下,分子量为1550,2120和2960g/mol的聚醋酸乙烯酯的浊点压力分别为13.48,13.83和15.43MPa,该结果表明聚醋酸乙烯酯在较低压力的超临界二氧化碳中溶解度十分有限. 展开更多
关键词 聚醋酸乙烯酯 聚合反应 超临界二氧化碳 浊点压力 亲二氧化碳聚合物
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Anionic polymerization initiated by lithium amides for preparing high molecular weight polyacrylonitrile
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作者 Xiaolin Shi Jingyang Jiang 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第2期473-476,共4页
Lithium amides have been proved to be effective anionic initiators for the anionic polymerization of acrylonitrile to get high molecular weight polyacrylonitrile in this study. Polyacrylonitrile with weightaverage mol... Lithium amides have been proved to be effective anionic initiators for the anionic polymerization of acrylonitrile to get high molecular weight polyacrylonitrile in this study. Polyacrylonitrile with weightaverage molecular weight ranging from 1.02 × 10~6 g/mol to 1.23 ×10~6 g/mol (M_w/M_n= 1.9-2.2) could be prepared utilizing lithium amides derived from diisopropylamine, diethylamine, hexamethyldisilazane,dicyclohexylamine, and 2,2,6,6-tetramethylpiperidine as initiators. The polymerization of acrylonitrile proceeded in a homogeneous manner in N,N-di methyl for mamide and insignificant contribution of side reactions was confirmed. 展开更多
关键词 ANIONIC POLYMERIZATION ACRYLONITRILE High molecular weight polymer Lithium AMIDES POLYACRYLONITRILE
(Arylimido)vanadium(V)-Alkylidene Complexes as Catalysts for Ring-opening Metathesis Polymerization(ROMP) of Cyclic Olefins: Ligand Design for Exhibiting the High Activity
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作者 Kotohiro Nomura Sapanna Chaimongkolkunasin 《高分子科学:英文版》 SCIE CAS CSCD 2019年第10期943-950,I0002,共9页
(Imido)vanadium(V)-alkylidene complexes of type V(CHSiMe3)(NR)(OR?)(PMe3)2 [R = Ad, C6H5, 2,6-Me2C6H3, 2,6-Cl2C6H3;R?= 2,6-Me2C6H3, 2,6-i Pr2C6H3, 2,6-F2C6H3, C6F5, C6Cl5] exhibited from moderate to remarkable catalyt... (Imido)vanadium(V)-alkylidene complexes of type V(CHSiMe3)(NR)(OR?)(PMe3)2 [R = Ad, C6H5, 2,6-Me2C6H3, 2,6-Cl2C6H3;R?= 2,6-Me2C6H3, 2,6-i Pr2C6H3, 2,6-F2C6H3, C6F5, C6Cl5] exhibited from moderate to remarkable catalytic activities for ringopening metathesis polymerization(ROMP) of norbornene(NBE). The catalytic activities were affected by the ligand substituents, and V(CHSiMe3)(N-2,6-Cl2C6H3)(OC6X5)(PMe3)2(X = F, Cl) demonstrated the exceptionally high catalytic activities for ROMP of NBE.The complexes polymerized cycloheptene(CHPE) and cis-cyclooctene(COE), and ROMP of COE by the OC6 Cl5 analogue proceeded in a living manner even at 80℃, and the activity increased with increasing the temperature up to 120 ℃. Highly active catalysts for ROMP of cyclic olefins(NBE, cyclopentene, and CHPE) can be generated in situ by premixing isolated V(CHSiMe3)(NC6F5)(O-2,6-iPr2C6H3)(PMe3)2 with 1.0 equiv. of C6F5OH or C6Cl5OH via immediate phenoxy exchange;the activity was affected by the kind of phenol added [TOF in the ROMPs of NBE: 4.62 × 10^4 min^–1(upon addition of C6F5OH) versus 37.3 min^–1(none)]. 展开更多
关键词 Olefin metathesis Molecular catalyst Ring-opening metathesis polymerization Cyclic olefin Vanadium catalyst
Regioselective Polymerizations of α-Olefins with an α-Diamine Nickel Catalyst
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作者 Heng Liao Jie Gao +2 位作者 Liu Zhong Hai-Yang Gao Qing Wu 《高分子科学:英文版》 SCIE CAS CSCD 2019年第10期959-965,I0003,共8页
Polymerizations of linear α-olefins(CnH2n, CH2=CH―R, R = Cn-2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains(Cn-2), while chain-straightening polymerizations of α-olefin... Polymerizations of linear α-olefins(CnH2n, CH2=CH―R, R = Cn-2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains(Cn-2), while chain-straightening polymerizations of α-olefins with nickel-based catalysts produce semicrystalline polyolefins. Polymerizations of various α-olefins were carried out using an α-diamine nickel catalyst with a significantly distorted chelating ring. The influences of temperature, monomer concentration, and chain length of α-olefins on polyolefin microstructure were examined in detail. The α-diamine nickel catalyst realized highly regioselective 2,1-insertion of α-olefins regardless of reaction temperature and monomer concentration. Increased chain length of α-olefins led to the formation of more linear polyolefin.Semicrystalline polyolefins with high melting temperatures(Tm) were made from α-olefins through highly regioselective 2,1-insertion and precise chain-straightening. 展开更多
关键词 Nickel catalyst Α-OLEFIN POLYMERIZATION Regioselectivity Chain walking
Preparation of Molecularly Imprinted Composites Initiated by Hemin/Graphene Hybrid Nanosheets and Its Application in Detection of Sulfamethoxazole 预览
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作者 Shao-fei GUO Xiao-yu CHEN +4 位作者 Peng WANG Cheng CHEN Rui-hua PAN Yue-tao LING Yi-zhu TANG 《当代医学科学(英文)》 SCIE CAS 2019年第1期159-165,共7页
Molecularly imprinted polymers(MIPs)exhibit high selectivity resulting from imprinted cavities and superior performance from functional materials,which have attracted much attention in many fields.However,the combinat... Molecularly imprinted polymers(MIPs)exhibit high selectivity resulting from imprinted cavities and superior performance from functional materials,which have attracted much attention in many fields.However,the combination of MIPs film and functional materials is a great challenge.In this study,hemin/graphene hybrid nanosheets(H-GNs)were used to initiate the imprinted polymerization by catalyzing the generation of free radicals.Thus,MIPs using sulfamethoxazole as the template was directly prepared on the surface of H-GNs without any film modification.Most importantly,the template could be absorbed on the H-GNs to enhance the number of imprinted sites per unit surface area,which could improve the selectivity of MIPs film.Thus,the composites could exhibit high adsorption capacity(29.4 mg/g),imprinting factor(4.2)and excellent conductivity,which were modified on the surface of electrode for rapid,selective and sensitive detection of sulfamethoxazole in food and serum samples.The linear range was changed from 5μg/kg to 1 mg/g and the limit of detection was 1.2μg/kg.This sensor was free from interference caused by analogues of sulfamethoxazole,which provides a novel insight for the preparation of MIPs-based sensor and its application in food safety monitoring and human exposure study. 展开更多
关键词 MIP/H-GNs COMPOSITES SULFAMETHOXAZOLE nano enzyme-mediated polymerization sensor DIETARY exposure
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Synthesis of Alkyne-functionalized Polymers via Living Anionic Polymerization and Investigation of Features during the Post-“thiol-yne” Click Reaction
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作者 Lin-Can Yang Li Han +5 位作者 Hong-Wei Ma Pi-Bo Liu He-Yu Shen Chao Li Song-Bo Zhang Yang Li 《高分子科学:英文版》 SCIE CAS CSCD 2019年第9期841-850,共10页
"Thiol-yne" click reaction has already been widely applied in synthesis and modification of new polymer structures or novel materials due to its specific features. However, in most studies, only chain-end st... "Thiol-yne" click reaction has already been widely applied in synthesis and modification of new polymer structures or novel materials due to its specific features. However, in most studies, only chain-end strategy was employed when using the di-addition feature of thiol-yne reaction, thus the in-chain di-addition strategy could endow us with a broader space to develop the synthesis of advanced polymers. Therefore, in this paper, the features of in-chain mono and di-addition were investigated when modifying the alkynefunctionalized polymers to prepare grafted polymers via thiol-yne click reaction. The results showed that it is almost impossible to obtain the in-chain di-adducts even under excess feeding of chain-end thiol-functionalized grafts, while only the in-chain mono-adducts could be obtained efficiently. Further researches investigated that the controlled grafting could be encountered when carrying out the thiol-yne click reaction between chain-end alkyne-functionalized polystyrenes and chain-end thiol-functionalized polystyrenes under proper feedings. Therefore, the effect of steric?hindrance might be the primary reason for the alternative grafting via thiol-yne click reaction between in-chain and chain-end alkyne-functionalized polymers. 展开更多
关键词 Alkyne-functionalized polymers In-chain di-addition Thiol-yne CLICK reaction Living ANIONIC polymerization
A Phenol-containing α-Diimine Ligand for Nickel-and Palladium-Catalyzed Ethylene Polymerization
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作者 Chen Tan Wen-Min Pang Chang-Le Chen 《高分子科学:英文版》 SCIE CAS CSCD 2019年第10期974-980,I0003,共8页
A phenol-containing dibenzhydryl-based α-diimine ligand bearing hydroxy group on para-position of aniline moiety was designed, synthesized, and investigated in Ni-and Pd-catalyzed ethylene polymerization. The Ni comp... A phenol-containing dibenzhydryl-based α-diimine ligand bearing hydroxy group on para-position of aniline moiety was designed, synthesized, and investigated in Ni-and Pd-catalyzed ethylene polymerization. The Ni complex bearing hydroxy groups resulted in not only high polyethylene molecular weight(Mn up to 1.5 × 10^~6), but also significantly increased melting temperature(Tm up to 123℃) and greatly decreased branching density(33/1000 C) versus the Ni catalyst bearing OMe group on para-position of aniline moiety. This is consistent with the hypothesis that the deprotonation of the phenol moiety generated a phenoxide bearing strong electrondonating O-substituent by methylaluminoxane(MAO) cocatalyst. The Pd complexes bearing hydroxy groups exhibited similar catalytic properties to those of the Pd catalyst bearing OMe groups did. 展开更多
关键词 Α-DIIMINE Ethylene polymerization Electronic effect PALLADIUM NICKEL
Deactivation Effect Caused by Catalyst-Cocatalyst Pre-contact in Propylene Polymerization with MgCl2-supported Ziegler-Natta Catalyst
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作者 Zhen Zhang Bai-Yu Jiang +2 位作者 Biao Zhang Zhi-Sheng Fu Zhi-Qiang Fan 《高分子科学:英文版》 SCIE CAS CSCD 2019年第10期1023-1030,I0005,共9页
Propylene slurry polymerization with a MgCl2-supported Ziegler-Natta catalyst containing internal electron donor was conducted after different durations of pre-contact of the catalyst with triethylaluminum cocatalyst.... Propylene slurry polymerization with a MgCl2-supported Ziegler-Natta catalyst containing internal electron donor was conducted after different durations of pre-contact of the catalyst with triethylaluminum cocatalyst. The number of active centers([C*]/[Ti])was determined by quenching the polymerization with 2-thiophenecarbonyl chloride and measuring sulfur content in the polymer. The pre-contact treatment caused selective deactivation of a part of active centers with low stereoselectivity and much lower activity in the initial stage of polymerization as compared with the polymerization run without the pre-contact stage. The active center concentration and polymerization activity decreased with prolonging of the pre-contact stage. The proportion of stereoselective active centers was increased by prolonging the pre-contact stage, so the isotacticity of produced polypropylene was enhanced. Release of active centers through catalyst particle fragmentation was significantly retarded, and the polymerization rate curve changed from decay type to induction type by the precontact treatment. In the induction period both non-stereoselective and stereoselective active centers were released and activated, resulting in gradual reduction of the polymer’s isotacticity in the first 5-10 min of polymerization. Selective deactivation of non-stereoselective active centers also took place in propylene polymerization using the catalyst without pre-contacting with the cocatalyst. In this case, the polymerization rate decayed with time after a short induction period of 2-5 min. Over reduction of the active center precursors with low stereoselectivity by triethylaluminum was considered as the reason for their deactivation during the pre-contact or the polymerization processes. 展开更多
关键词 PROPYLENE Polymerization Supported Ziegler-Natta catalyst COCATALYST Pre-contact
Effects of Main-chain and Chain-ends on the Organogelation of Stearoyl Appended Pendant Valine Based Polymers
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作者 Mridula Nandi Swagata Pan +1 位作者 Dipannita Ghosh Priyadarsi De 《高分子科学:英文版》 SCIE CAS CSCD 2019年第9期903-911,共9页
In this work, we investigated the effect of hydrophobic interactions between the polymeric backbone and chain-end groups on the self-assembly pathway of stearoyl appended side-chain valine (Val)-based poly(methacrylat... In this work, we investigated the effect of hydrophobic interactions between the polymeric backbone and chain-end groups on the self-assembly pathway of stearoyl appended side-chain valine (Val)-based poly(methacrylate/acrylate) homopolymers in different organic hydrocarbons. Gelation studies conducted revealed that while polymers with polyacrylate as backbone induces gelation in several organic hydrocarbons, polymers with polymethacrylate in the main-chain significantly hinders macroscopic gelation. Morphology of the organogels was analysed by field emission scanning electron microscopy (FESEM), and mechanical strengths of the organogels were determined by rheological measurements. Reversible addition-fragmentation chain transfer (RAFT) polymerization chain transfer agents (CTA)s,[R1 —S—C=(S)—S—R2] with different —Ri and — R2 groups, have been employed to study the effect of structural variation at the chain-end on macroscopic assembly mechanism. We found that the additional interactions between terminal groups via hydrogenbonding or n-n stacking interactions or both help to build up the self-assembly pathway and thereby produces mechanically stable organogels. 展开更多
关键词 Organogelation HYDROPHOBIC interactions Poly (methacrylate/aery late) BACKBONE RAFT polymerization Self-assembly
Activity Enhancement of MgCl2-supported Ziegler-Natta Catalysts by Lewis-acid Pre-treatment for Ethylene Polymerization
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作者 Matthieu Humbert Sebastien Norsic +1 位作者 Jean Raynaud Vincent Monteil 《高分子科学:英文版》 SCIE CAS CSCD 2019年第10期1031-1038,I0006,共9页
Ziegler-Natta precatalysts were synthetized from Lewis-base-modified-MgCl2 supports and treated by various Lewis acids,prior to activation by triethylaluminum, in order to increase their activity in ethylene polymeriz... Ziegler-Natta precatalysts were synthetized from Lewis-base-modified-MgCl2 supports and treated by various Lewis acids,prior to activation by triethylaluminum, in order to increase their activity in ethylene polymerization. BCl3 provided the highest increase in activity. Interestingly, polymerization results showed no substantial modification of polymer properties, which is consistent with that Lewis acid only promotes the creation of new active sites, after activation by TEA, possessing very similar features to the original ones achievable with conventional precatalysts(i.e. without Lewis-acid treatment). 展开更多
关键词 Ziegler-Natta catalysis Ethylene polymerization Heterogeneous catalysis Lewis acids
Monomer-activated Copolymerization of Ethylene Oxide and Epichlorohydrin: In Situ Kinetics Evidences Tapered Block Copolymer Formation
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作者 Ann-Kathrin Danner Daniel Leibig +1 位作者 Lea-Marie Vogt Holger Frey 《高分子科学:英文版》 SCIE CAS CSCD 2019年第9期912-918,共7页
The monomer-activated anionic ring-opening copolymerization (AROP) of ethylene oxide (EO) and epichlorohydrin (ECH) using tetraoctylammonium bromide as an initiator and triisobutylaluminum (i-Bu3Al) as an activator wa... The monomer-activated anionic ring-opening copolymerization (AROP) of ethylene oxide (EO) and epichlorohydrin (ECH) using tetraoctylammonium bromide as an initiator and triisobutylaluminum (i-Bu3Al) as an activator was studied. The properties of the copolymers as well as the microstructure have been analyzed in detail via an in situ NMR kinetics study. The statistical copolymers exhibited molecular weights ranging from 2350 g·mol^-1 to 38000 g·mol^-1 (measured by SEC, PEG-standards) and moderate dispersities of 1.27-1.44. The thermal property tests revealed both a glass transition and melting for all copolymers, supporting a block-like nature. Applying in situ NMR kinetic measurements, the reactivity ratios of EO and ECH were determined to be strongly disparate, i.e., rEo = 9.2 and rECH = 0.10. This shows that the simple one-pot statistical anionic copolymerization of EO and ECH via the monomer-activated AROP resulted in the formation of strongly tapered, block-like structures. Furthermore, post-polymerization functionalization of the reactive chloromethyl groups by nucleophilic displacement was investigated for the copolymers. Copolymerization of EO and ECH offers a broad platform for further functionalization and therefore the possibility to prepare a variety of multifunctional PEGs. 展开更多
关键词 EPICHLOROHYDRIN Polymerization RING-OPENING COPOLYMERIZATION Reactivity ratios EPOXIDE
Lewis acid/base modulation inβ-diiminate zinc-catalyzed switchable ring-opening polymerization of rac-lactide
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作者 Pan Zhang Minhui Zhao +1 位作者 Wenmin Pang Changle Chen 《中国科学:化学英文版》 SCIE EI CAS CSCD 2019年第4期475-478,共4页
Twoβ-diiminate zinc complexes were prepared and found to show high activity and well-controlled catalytic behavior in the ring-opening polymerization of rac-lactide.Coordination of the Lewis acid to the zinc complexe... Twoβ-diiminate zinc complexes were prepared and found to show high activity and well-controlled catalytic behavior in the ring-opening polymerization of rac-lactide.Coordination of the Lewis acid to the zinc complexes completely terminated the polymerization.The coordinated Lewis acid was easily cleaved by using a Lewis base,so that the polymerization could resume.Thus,switchable polymerization could be realized by the subsequent addition of a Lewis acid and a Lewis base.This work provides a new strategy to control the ring-opening polymerization of rac-lactide. 展开更多
关键词 RING-OPENING polymerization β-diimine zinc catalysts MODULATION
Functionalized Copolymers of Isobutylene with Vinyl Phenol: Synthesis, Characterization, and Property
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作者 Shi-Xuan Yang Zi-Yu Fan +2 位作者 Feng-Yu Zhang Si-Hao Li Yi-Xian Wu 《高分子科学:英文版》 SCIE CAS CSCD 2019年第9期919-929,共11页
The random copolymers of isobutylene (IB) with polar comonomers of 4-acetoxystyrene (ACS) or 4-tert-butoxystyrene (TBO), P(IB-co-ACS) and P(IB-co-TBO), could be successfully synthesized via cationic copolymerization w... The random copolymers of isobutylene (IB) with polar comonomers of 4-acetoxystyrene (ACS) or 4-tert-butoxystyrene (TBO), P(IB-co-ACS) and P(IB-co-TBO), could be successfully synthesized via cationic copolymerization with FeCh-based initiating system. The kinetics of the cationic copolymerization process was in situ investigated by inserting a diamond probe into the reaction system by ATR-FTIR spectroscopy. The chemical structure and incorporation content of polar comonomers in the copolymers were characterized by GPC with RI/UV dual detectors and 1H-NMR spectroscopy. The corresponding functionalized random copolymers of IB with vinyl phenol P(IB-co-POH) carrying phenolic hydroxyl side groups could be further prepared via the complete hydrolysis of acetoxyl side groups in P(IB-co-ACS) or tert-butoxyl side groups in P(IB-co-TBO) copolymers. The functionalized P(IB-co-POH) copolymers became hydrophilic with water contact angle (WCA) of ca. 80° for the self-assembly in hot water, compared to the hydrophobic polyisobutylene with WCA of ca. 110°. The functionalized P(IB-co-POH) copolymers also displayed an excellent self-healing property due to the interaction of intermolecular hydrogen bonding and formation of three dimentional supramolecular networks from phenolic hydroxyl side groups. Furthermore, P(IB-co-POH) copolymers also provided a good matrix for the homogeneous dispersion for silica nanoparticles due to the formation of hydrogen bonding between copolymer chains and silica nanoparticles. 展开更多
关键词 CATIONIC polymerization ISOBUTYLENE COPOLYMERS Polar MONOMER FUNCTIONALIZED polyisobutylenes
含镁离子对硅酸溶液胶凝行为的影响 预览
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作者 王平 尤润泽 +1 位作者 申星梅 杨春 《山东化工》 CAS 2019年第17期36-37,41共3页
向不含金属离子的硅酸溶液中加入金属镁离子,研究了体系pH值、温度、镁离子浓度对硅酸溶液胶凝时间以及镁离子对胶凝产物基团的影响。结果表明,加入镁离子的硅酸溶液体系胶凝曲线最高点出现在pH值=1.5附近;随体系温度和镁离子浓度的升高... 向不含金属离子的硅酸溶液中加入金属镁离子,研究了体系pH值、温度、镁离子浓度对硅酸溶液胶凝时间以及镁离子对胶凝产物基团的影响。结果表明,加入镁离子的硅酸溶液体系胶凝曲线最高点出现在pH值=1.5附近;随体系温度和镁离子浓度的升高,含镁离子硅酸溶液的胶凝时间逐渐缩短;镁离子的加入导致凝胶产物部分红外特征吸收峰强度变弱。 展开更多
关键词 硅酸溶液 镁离子 胶凝时间 聚合
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芳纶纤维的研究现状与进展 预览
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作者 袁玥 李鹏飞 凌新龙 《纺织科学与工程学报》 CAS 2019年第1期146-152,共7页
简述了芳纶纤维的品种及性能,分析了当前国内外芳纶纤维的发展现状,概述了芳纶纤维的生产方法,详细叙述了超声波、等离子体、高能射线、紫外辐照、涂覆的物理方法和表面刻蚀、表面接枝、超临界二氧化碳改性、络合改性的化学方法对芳纶... 简述了芳纶纤维的品种及性能,分析了当前国内外芳纶纤维的发展现状,概述了芳纶纤维的生产方法,详细叙述了超声波、等离子体、高能射线、紫外辐照、涂覆的物理方法和表面刻蚀、表面接枝、超临界二氧化碳改性、络合改性的化学方法对芳纶纤维表面的改性研究。简述了当前芳纶纤维的主要应用领域,并结合我国芳纶纤维生产的实际情况,进行了展望。 展开更多
关键词 芳纶纤维 聚合 改性 应用
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