Despite the growing interest in fast-cha rging solid-state lithium(Li)-metal batteries(SSLMBs),their practical implementation has yet to be achieved,primarily due to an incomplete understanding of the disparate and of...Despite the growing interest in fast-cha rging solid-state lithium(Li)-metal batteries(SSLMBs),their practical implementation has yet to be achieved,primarily due to an incomplete understanding of the disparate and often conflicting requirements of the bulk electrolyte and the electrode-electrolyte interphase.Here,we present a weakly coordinating cationic polymer electrolyte(WCPE)specifically designed to regulate the Li^(+)coordination structure,thereby enabling fast-charging SSLMBs.The WCPE comprises an imidazolium-based polycationic matrix combined with a succinonitrile(SN)-based highconcentration electrolyte.Unlike conventional neutral polymer matrices,the polycationic matrix in the WCPE competes with Li^(+)for interactions with SN,weakening the original coordination between SN and Li^(+).This modulation of SN-Li^(+)interaction improves both Li^(+)conductivity of the WCPE(σ_(Li^(+))=1.29mS cm^(-1))and redox kinetics at the electrode-electrolyte interphase.Consequently,SSLMB cells(comprising LiFePO_(4)cathodes and Li-metal anodes)with the WCPE achieve fast-charging capability(reaching over 80%state of charge within 10 min),outperforming those of previously reported polymer electrolytebased SSLMBs.展开更多
Living cationic polymerization of 4-acetoxystyrene(STO)was conducted in CH_(2)Cl_(2) at-15℃ using a dicumyl chloride(DCC)/SnCl_(4)/nBu_(4)NBr initiating system.Impurity moisture initiation was inhibited by adding pro...Living cationic polymerization of 4-acetoxystyrene(STO)was conducted in CH_(2)Cl_(2) at-15℃ using a dicumyl chloride(DCC)/SnCl_(4)/nBu_(4)NBr initiating system.Impurity moisture initiation was inhibited by adding proton trap 2,6-di-tert-butylpyridine(DTBP),and the controlled initiation of DCC was confirmed by ^(1)H nuclear magnetic resonance(^(1)H-NMR)spectroscopy and matrix-assisted laser desorption ionization time-offlight mass(MALDI-TOF-MS)spectrometry.The polymerization kinetics were analyzed to for optimizing the polymerization rate.Allyl-telechelic PSTOs(allyl-PSTO-allyl)with molecular weight(Mn)range of 3540–7800 g/mol and narrow molecular weight dispersity(Mw/Mn)about 1.25 were prepared through nucleophilic substitution with allyltrimethylsilane(ATMS)at approximately 40%monomer conversion.The experimental results indicate that the substitution efficiency of ATMS increased with higher ATMS concentration,temperature,and extended reaction time.Nearly unity ally-functionality for allyl-PSTO-allyl was achieved by adding sufficient SnCl_(4) prior to the substitution.展开更多
A novel simple but effective initiating system of H2O/AlCl3/veratrole （VE） has been developed to synthesize high molecular weight polyisobutylene （PIB） at elevated temperatures via cationic polymerization of isobu...A novel simple but effective initiating system of H2O/AlCl3/veratrole （VE） has been developed to synthesize high molecular weight polyisobutylene （PIB） at elevated temperatures via cationic polymerization of isobutylene （IB） in solvent mixture of hexane/methylene dichloride （n-Hex/CH2Cl2 = 2/1, V/V）. VE played very important roles in decreasing cationicity of the growing chain ends, suppressing side reactions of chain transfer and termination during polymerization, leading to production of high molecular weight PIBs. PIBs with high yields, having very high weight-average molecular weight （Mw） of 1117000 and 370000 g/tool could be synthesized with H2O/AICl3/VE initiating system at VE concentration of 5.4 mmol/L at -80 and -60 ℃ respectively. Molecular weight of PIB increased remarkably with increasing VE concentration. The reaction order with respect to VE concentration was determined to be -3.52 via FTIR spectroscopy in combination with a diamond tipped attenuated total reflectance （ATR） immersion probe. The negative reaction order of VE was consistent with its retarding effect on IB polymerization by interacting with the propagating species. Molecular weight of PIB decreased with increasing polymerization temperature. The activation energy for polymerization degree （Eop） could be determined to be around -23 kJ/mol when VE concentration was 5.4 mmol/L or 6.4 mmol/L.展开更多
The cationic polymerizations of isobutylene （IB） coinitiated by AlCl3 were carried out in solvent mixture of nhexane/methylene dichloride （n-hex/CH2Cl2） of 60/40 V/V in the presence of ethyl benzoate （EB） at var...The cationic polymerizations of isobutylene （IB） coinitiated by AlCl3 were carried out in solvent mixture of nhexane/methylene dichloride （n-hex/CH2Cl2） of 60/40 V/V in the presence of ethyl benzoate （EB） at various temperatures range from -80℃ to -30℃. The effects of EB concentration （[EB]） and polymerization temperature on monomer conversion, weight-average molecular weight （Mw） and molecular weight distribution （MWD, Mw/Mn） of polyisobutylene （PIB） products were investigated. The rate of polymerization decreased while Mw of PIB products increased with increasing [EB]. The polymers with high molecular weight could be prepared in the presence of a suitable amount of EB. Significantly, the polymers with high Mw of 80.2 × 10^4 and 65.4 × 10^4 could be produced at -80℃ and -70℃ at [EB] = 0.24 × 10^3 mol/L respectively, which were much higher than that （Mw = 57.9 × 10^4） of PIB prepared at -100℃ in the absence ofEB. A simple but effective method for preparing the high molecular weight polyisobutylenes was developed in this work. It has been also found that the activation energy for propagation （Ep） depended on the polymerization temperature range in the presence of EB. An obvious inflection of the linear plots of lnXn versus 1/Tp occurred at the temperature range from -60℃ to -50℃ at four different concentrations of EB from 0.19 × 10^3 mol/L to 0.33× 10^3 tool/L, and thus the inflection temperature （Tinf） was in the range of -60℃ to -50℃. When [EB] was in the range of 0.24 × 10^3 mol/L to 0.33× 10^3 mol/L, Ep was determined to be around -12 kJ/mol when the polymerization was carried out at temperatures from -80℃ to Tinf and to be around -28 kJ/mol at temperatures from Tinf to -15℃ respectively.展开更多
The highly reactive polyisobutylenes(PIBs) withα-double bonds(87.5 mol%) or tert-chloro(tert-Cl) groups(95 mol%) could be prepared via the cationic polymerization of isobutylene(IB) coinitiated by BF_3 or TiCl_4 resp...The highly reactive polyisobutylenes(PIBs) withα-double bonds(87.5 mol%) or tert-chloro(tert-Cl) groups(95 mol%) could be prepared via the cationic polymerization of isobutylene(IB) coinitiated by BF_3 or TiCl_4 respectively.The Friedel-Crafts alkylation of diphenylamine(DPA) with the highly reactive PIB withα-double bonds was further conducted under different conditions,such as at different alkylation temperature,in the mixed solvents of CH_2Cl_2/n-hexane with different solvent polarity and at DPA concentr...展开更多
To improve the hydrophilicity ofpoly（styrene-b-isobutylene-b-styrene） （SIBS）, this study focuses on the synthesis of novel functional ABA triblock copolymer thermoplastic elastomers （TPEs） with polyisobutylene ...To improve the hydrophilicity ofpoly（styrene-b-isobutylene-b-styrene） （SIBS）, this study focuses on the synthesis of novel functional ABA triblock copolymer thermoplastic elastomers （TPEs） with polyisobutylene （PIB） as rubbery segments. The precursor poly{（styrene-co-4-[2-（tert-butyldimethylsiloxy） ethyl]styrene）-b-isobutylene-b-（styrene-co-4-[2- （tert-butyldimethylsiloxy）ethyl]styrene）}（P（St-co-TBDMES）-PIB-P（St-co-TBDMES）） triblock copolymer was first synthesized by living sequential cationic copolymerization of isobutylene （IB） with styrene （St） and 4-[2-（tert- butyldimethylsiloxy）ethyl]styrene （TBDMES） using 1,4-di（2-chloro-2-propyl）benzene （DiCumC1）/titanium tetrachloride （TiCla）/2,6-di-tert-butylpyridine （DtBP） as the initiating system. Then, P（St-co-TBDMES）-PIB-P（St-co-TBDMES） was hydrolyzed in the presence of tetra-butylammonium fluoride to yield poly{[styrene-co-4-（2-hydroxyethyl）styrene]-b- isobutylene-b-[styrene-co-4-（2-hydroxyethyl）styrene]} （P（St-co-HOES）-PIB-P（St-co-HOES）） with pendant hydroxyl groups. P（St-co-HOES）-PIB-P（St-co-HOES） used as the paclitaxel carrier was also investigated in this study. Comparing with SIBS, P（St-co-HOES）-PIB-P（St-co-HOES） has exhibited better compatibility with paclitaxel and higher release rate.展开更多
We report herein the cationic polymerization of isobutylene(IB)under mild conditions is realized with a new binary initiation system generated by simply mixing a Lewis super acid Al(C_(6)F_(5))_(3) and a substituted p...We report herein the cationic polymerization of isobutylene(IB)under mild conditions is realized with a new binary initiation system generated by simply mixing a Lewis super acid Al(C_(6)F_(5))_(3) and a substituted phenol(RPhOH).Polymers with medium and/or high molecular weights(M_(W)=4.9×10^(4)-27.7×10^(4) g·mol^(-1))can be obtained in toluene and temperatures from-20℃to 0℃.NMR spectrum analysis and DFT sim ulation reveals the in situ generated acidic coordinating complex Ak(C_(6)F_(5))_(3)·RPhOH is the initiating active species,which fu rther tran sformed into the ion-pair[Al(C_(6)F_(5))_(3)ORPh]^(-)[PIB]^(+)of the active intermediates upon growing IB monomers where the counter anion[Al(C_(6)F_(5))_(3)R^(O)Ph]-coordinates to the macrocation via the phenoxy oxygen.The catalyst performances are the concert effects of the steric bulkiness and electronics of the counter anion on the coordinating strength to the macrocation,which is significant to the stability of the active species.展开更多
Mechanistic transformation approach has been widely applied in polymer synthesis due to its unique feature combining structurally different polymers prepared by different polymerization mechanisms.Reported methods for...Mechanistic transformation approach has been widely applied in polymer synthesis due to its unique feature combining structurally different polymers prepared by different polymerization mechanisms.Reported methods for the formation of block and graft copolymers through mechanistic transformation involve almost all polymerizations modes.However,certain polymerization processes require extensive purification processes,which can be time-consuming and problematic.Recent developments on controlled/living polymerizations involving radical and cationic mechanisms with the ability to control molecular weight and functionality led to new pathways for mechanistic transformations.In this mini-review,we systematically discussed relevant advances in the field through three main titles namely(i)from radical to cationic mechanism,(ii)from cationic to radical mechanism,and(iii)application of specific catalyst systems for both radical and cationic polymerizations.展开更多
The cationic polymerization of C4 mixed feed and isobutylene co-initiated by AlCl3xOiPr2,iBuAlC12xnOiPr2,and[emim]Cl-FeCl3xnOiPr2([emim]Cl:1-ethyl-3-methylimidazolium chloride)has been investigated.AlCl3xOiPr2 co-init...The cationic polymerization of C4 mixed feed and isobutylene co-initiated by AlCl3xOiPr2,iBuAlC12xnOiPr2,and[emim]Cl-FeCl3xnOiPr2([emim]Cl:1-ethyl-3-methylimidazolium chloride)has been investigated.AlCl3xOiPr2 co-initiated cationic polymerization of C4 mixed feed proceeds at a lower rate than polymerization of isobutylene affording polymers with higher molecular weight.Complexes of iBuAlCh with di isopropyl ether of different compositions are more suitable co-initiators than AlCl3xOiPr2 for the synthesis of highly reactive polyisobutylene(HR PIB)from C4 mixed feed due to their higher activity in the polymerization as well as possibility to prepare polyisobutylenes with lower molecular weight and higher content of exo-olefin end groups.However,iBuA1C12 needs activating via addition of external water(initiator)and/or interaction with salts hydrates in order to increase the reaction rate and the saturated monomer conversion.[Emim]Cl-FeC13/iPr2O is a quite promising catalyst for the preparation of HR PIB with high exo-olefin end group content(>80%)and relatively low polydispersity(Mw/Mn<2.8)via cationic polymerization of C4 mixed feed.The sonication of reaction mixture in case of using[emim]Cl-FeCh allowed increasing the reaction rate and decreasing the molecular weight.展开更多
PEGylated poly（2-（dimethylamino）ethyl methacrylate） with comb-like architecture was synthesized by two-step polymerization. First,poly（oligo（ethylene glycol） malicate）（POEGMA） bearing pendant hydroxyl groups...PEGylated poly（2-（dimethylamino）ethyl methacrylate） with comb-like architecture was synthesized by two-step polymerization. First,poly（oligo（ethylene glycol） malicate）（POEGMA） bearing pendant hydroxyl groups was prepared by direct polycondensation of oligo（ethylene glycol） and malic acid in the presence of scandium triflate as chemoselective catalyst.Then the poly（2- （dimethylamino）ethyl methacrylate） side chains were grafted from the POEGMA backbone by atom transfer radical polymerization （ATRP） after the hydroxyl groups were modified into bromo-ester form,resulting in a PEGylated cationic copolymer with branched architecture.展开更多
Cationic polymer drilling fluid (CPDF) is a new water base drilling fluid in which high molecular weight (HMW) cationic polymer (CPAM) is an encapsulating and flocculating agent and organic quaternary ammonium compoun...Cationic polymer drilling fluid (CPDF) is a new water base drilling fluid in which high molecular weight (HMW) cationic polymer (CPAM) is an encapsulating and flocculating agent and organic quaternary ammonium compound (NW-1) acts as shale inhibitor. This paper describes the experimental results of cuttings recovery, particle size distribution layer spacing and Zeta potential, and discusses the inhibition of CPDF system and its major additives. The advantages of CPDF will be proved by its application in well LX-2.展开更多
A star-shaped multifunctional styrene-isoprene copolymer was synthesized with n-BuLi as initiator, divinyl benzene as coupling agent, cyclobexane as solvent by living anionic polymerization. Using this polymer as graf...A star-shaped multifunctional styrene-isoprene copolymer was synthesized with n-BuLi as initiator, divinyl benzene as coupling agent, cyclobexane as solvent by living anionic polymerization. Using this polymer as grafting agent, a novel star-shaped branched polymer, containing several polyisobutylene, was prepared via cationic ~aolymerization. The star PS-b-PI and star-branched polyisobutylene were characterized by GPC, ＇HNMR and FT-IR, and the effects of different adding order and the amount of grafting agent were investigated.展开更多
The cationic polymerizations of 1, 3-pentadiene were initiated by AlCl_3 in n-hexaneat 30℃ in the presence of alkyl halides, i.e., tert-butyl chloride, tert-butyl bromide andisobutyl chloride. The effects of these ha...The cationic polymerizations of 1, 3-pentadiene were initiated by AlCl_3 in n-hexaneat 30℃ in the presence of alkyl halides, i.e., tert-butyl chloride, tert-butyl bromide andisobutyl chloride. The effects of these halides on the polymer yield, molecular weight,crosslinking reaction, cyclization and polymer microstructure, have been investigated. Twomain side reactions, crosslinking and cyclization, were suppressed and reduced by theaddition of the halides. The proportion of 1, 4 units of polymer chains was increasedby the presence of the halides, which reduced the polymer yield and the molecular weightof polymers.展开更多
Cationic polymerizations of 1,3-pentadiene (PD) initiated by trimethylsilyl chloride (TMSCl) incombination with TiCl_4 were carried out in n-hexane at 30℃. The yield of polymer was greatly increased bythe addition of...Cationic polymerizations of 1,3-pentadiene (PD) initiated by trimethylsilyl chloride (TMSCl) incombination with TiCl_4 were carried out in n-hexane at 30℃. The yield of polymer was greatly increased bythe addition of TMSCl, indicating that the TMSCl/TiCl_4 combination is an efficient initiating system for PDcationic polymerization. However, the introduction of TMSCl gave rise to a drop in the molecular weight ofthe polymer. Kinetic results demonstrated that the polymerization initiated by TMSCl/TiCl_4 is 4.5 times fasterthan that induced by TiCl_4 alone. Various ethers were used to mediate the TMSCl/TiCl_4 initiating system.Adding diphenyl ether could increase both the yield and molecular weight of the polymer. Structural evidenceillustrates that the polymerization is indeed initiated by TiCl_4 in combination with HCl resulting fromhydrolysis by adventitious water.展开更多
The cationic polymerization of 1, 3-pentadiene was initiated by the organic azide/Et_2 AlClinitiating system in CH_2Cl_2 and n-hexane. The polymerizations were also carried out in parallelwith organic chloride/Et_2AlC...The cationic polymerization of 1, 3-pentadiene was initiated by the organic azide/Et_2 AlClinitiating system in CH_2Cl_2 and n-hexane. The polymerizations were also carried out in parallelwith organic chloride/Et_2AlCl and Et_2 AlCl alone for comparison. The Et_2 AlCl- induced polymer-ization gives a low yield while the polymerization initiated by organic chloride/Et_2 AlCl producesmainly insoluble product. In contrast, the polymerization with azide/Et,AlCl has a high conver-sion and the resulting polymer having a high molecular weight is totally soluble. The SEC spectraof the polymers have clearly shown the differences between these initiating systems.展开更多
Efficient segregation of TcO_(4)^(-)from high-level radioactive wastes(HLW)is critical for robust nuclear waste management and environmental protection.However,achieving deep decontamination is especially challenging ...Efficient segregation of TcO_(4)^(-)from high-level radioactive wastes(HLW)is critical for robust nuclear waste management and environmental protection.However,achieving deep decontamination is especially challenging in complex conditions of strong basicity,high radiation,and excessively competitive anions.Herein,we addressed the long-term challenge by modifying the imidazolium core with phenyl,trimethylphenyl,and benzyl groups in a flexible polymer chain,which constructs a precisely targeted microenvironment for selective TcO_(4)^(-)capture.This custom-engineered material(SCU-CPN-7)exhibits fast kinetics,high adsorption capacity(314.7 mg/g),excellent distribution coefficient(1.3×10^(7) mL/g),and remarkable efficiency in TcO_(4)^(-)uptake under the combining extreme conditions of strong alkalinity(1 M NaOH)and high radioactivity.More importantly,owing to the synergistic effects of the hydrophobic effect,electrostatic affinity,and p-πinteractions,SCU-CPN-7 demonstrates exceptional selectivity,capable of almost quantificationally removing TcO_(4)^(-)in the coexistence of a large excess of NO_(3)^(-)and SO_(4)^(2-),leading to an unparalleled uptake performance of TcO_(4)^(-)from simulated HLW in both batch and dynamic column separation tests.展开更多
The development of synthetic hybrid biological systems integrating photosynthetic organisms with organic-abiotic functional materials holds significant promise for enhancing photosynthetic processes.The artificial reg...The development of synthetic hybrid biological systems integrating photosynthetic organisms with organic-abiotic functional materials holds significant promise for enhancing photosynthetic processes.The artificial regulation of the state transition between photosystem I(PSI)and photosystem II(PSII)represents a strategic and promising approach for improving the efficiency of natural photosynthesis.In this study,we demonstrate that poly(benzimidazolium-phenylthiophene)(CP4)featuring a flexible cationic backbone exhibits superior ultraviolet light-harvesting capability.The polymer CP4 enhanced PSI activity in Chlorella pyrenoidosa(C.pyrenoidosa),subsequently promoting PSII activity and augmenting overall photosynthetic performance.During light-dependent reactions,CP4 significantly accelerated photosynthetic electron transfer,resulting in a 330%increase in the production of oxygen and 93%and 96%increases in the ATP and NADPH contents,respectively.In the context of dark reactions,CP4 facilitated the conversion and utilization of light energy,leading to a 6%increase in both carbohydrate and protein contents.These findings indicate that synthetic light-harvesting polymer materials exhibit considerable application potential in the field of biomass production through enhancement of natural photosynthetic efficiency.展开更多
In this work, a fluorescent monomer 2-（9-carbazolyl） ethyl vinyl ether（CEVE） was synthesized in our lab, and its photo-induced living cationic copolymerization behavior with isobutyl vinyl ether（IBVE） was invest...In this work, a fluorescent monomer 2-（9-carbazolyl） ethyl vinyl ether（CEVE） was synthesized in our lab, and its photo-induced living cationic copolymerization behavior with isobutyl vinyl ether（IBVE） was investigated in detail using diphenyliodonium chloride（DPICl）/2,2-dimethoxy-2-phenylacetophenone（DMPA） and zinc bromide（Zn Br2） initiating system in dichloromethane solution at 5 °C, -5 °C, and -15 °C, respectively. The living nature of this copolymerization system was confirmed by adding fresh comonomer method after the copolymerization almost finished. In addition, the obtained fluorescent copolymer poly（IBVE-co-CEVE） has a low glass transition temperature（Tg）, below -10 °C.展开更多
Cationic ring opening polymerization of octamethylcyclotetrasiloxane （Da） initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher ...Cationic ring opening polymerization of octamethylcyclotetrasiloxane （Da） initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher temperature was found beneficial for the reaction process while stirring intensity beyond a certain level showed no obvious effect on the reaction rate. Polymers were characterized by Fourier transform infrared, proton nuclear magnetic resonance （IH-NMR） and gel perneation chromotography. The width of molecular mass distribution was found ranging between 1.2 and 1.4, which is extraordinarlly narrow compared with that of cationic polymerizations reported elsewhere （〉 1.9）. The results were believed due to the absence of free proton and counter ion which simplifies the polymerization process and the huge steric hindrance provided by bentonite particles which keeps the propagation of polysiloxane onto the surface of bentonite particles in a much more regular way. A feasible mechanism is proposed and seems to be supported well by experiments. Additionally, from the results of α, ω-dihydrogen terminated polysiloxanes prepared, the possibility of applying this potential environmentally friendly heterogeneous catalyst in industrial polymerization of cyclosiloxanes is anticipated.展开更多
Cationic polymerization of styrene has been achieved using several novel acidic initiators in room temperature ionic liquids (ILs) under mild reaction conditions to obtain polymers of low molecular weight with narrow ...Cationic polymerization of styrene has been achieved using several novel acidic initiators in room temperature ionic liquids (ILs) under mild reaction conditions to obtain polymers of low molecular weight with narrow polydispersity. Both strong protic acids such as bis(trifluoromethanesulfonyl) amide acid (HTFSA) and a moderately weak acid such as bisoxalato phosphorous acid (HBOP) have been studied as initiators. It has been observed that HTFSA initiates the polymerization rapidly even at room temperature and below, as compared to HBOP which produces a slower polymerization requiring elevated temperatures to complete. The relative difference in reactivity of the initiators as compared to the previously described HBOB initiator is discussed in terms of the difference in their proton acidity and the consequential basicity of the anions. The efficiency of different ILs as the reaction solvent is also presented.展开更多
基金supported by the Basic Science Research Program(RS-2024-00344021,RS-2023-00261543,and RS-202300257666)through the National Research Foundation of Korea(NRF),the National Research Council of Science(000)Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(RS-2024-00420590,HRD Program for Industrial Innovation)The computational resources were provided by KITSI(KSC-2024-CRE-0143)。
文摘Despite the growing interest in fast-cha rging solid-state lithium(Li)-metal batteries(SSLMBs),their practical implementation has yet to be achieved,primarily due to an incomplete understanding of the disparate and often conflicting requirements of the bulk electrolyte and the electrode-electrolyte interphase.Here,we present a weakly coordinating cationic polymer electrolyte(WCPE)specifically designed to regulate the Li^(+)coordination structure,thereby enabling fast-charging SSLMBs.The WCPE comprises an imidazolium-based polycationic matrix combined with a succinonitrile(SN)-based highconcentration electrolyte.Unlike conventional neutral polymer matrices,the polycationic matrix in the WCPE competes with Li^(+)for interactions with SN,weakening the original coordination between SN and Li^(+).This modulation of SN-Li^(+)interaction improves both Li^(+)conductivity of the WCPE(σ_(Li^(+))=1.29mS cm^(-1))and redox kinetics at the electrode-electrolyte interphase.Consequently,SSLMB cells(comprising LiFePO_(4)cathodes and Li-metal anodes)with the WCPE achieve fast-charging capability(reaching over 80%state of charge within 10 min),outperforming those of previously reported polymer electrolytebased SSLMBs.
基金financially supported by the National Natural Science Foundation of China(No.52373011)。
文摘Living cationic polymerization of 4-acetoxystyrene(STO)was conducted in CH_(2)Cl_(2) at-15℃ using a dicumyl chloride(DCC)/SnCl_(4)/nBu_(4)NBr initiating system.Impurity moisture initiation was inhibited by adding proton trap 2,6-di-tert-butylpyridine(DTBP),and the controlled initiation of DCC was confirmed by ^(1)H nuclear magnetic resonance(^(1)H-NMR)spectroscopy and matrix-assisted laser desorption ionization time-offlight mass(MALDI-TOF-MS)spectrometry.The polymerization kinetics were analyzed to for optimizing the polymerization rate.Allyl-telechelic PSTOs(allyl-PSTO-allyl)with molecular weight(Mn)range of 3540–7800 g/mol and narrow molecular weight dispersity(Mw/Mn)about 1.25 were prepared through nucleophilic substitution with allyltrimethylsilane(ATMS)at approximately 40%monomer conversion.The experimental results indicate that the substitution efficiency of ATMS increased with higher ATMS concentration,temperature,and extended reaction time.Nearly unity ally-functionality for allyl-PSTO-allyl was achieved by adding sufficient SnCl_(4) prior to the substitution.
基金financially supported by the National Natural Science Foundation of China(No.20934001)
文摘A novel simple but effective initiating system of H2O/AlCl3/veratrole （VE） has been developed to synthesize high molecular weight polyisobutylene （PIB） at elevated temperatures via cationic polymerization of isobutylene （IB） in solvent mixture of hexane/methylene dichloride （n-Hex/CH2Cl2 = 2/1, V/V）. VE played very important roles in decreasing cationicity of the growing chain ends, suppressing side reactions of chain transfer and termination during polymerization, leading to production of high molecular weight PIBs. PIBs with high yields, having very high weight-average molecular weight （Mw） of 1117000 and 370000 g/tool could be synthesized with H2O/AICl3/VE initiating system at VE concentration of 5.4 mmol/L at -80 and -60 ℃ respectively. Molecular weight of PIB increased remarkably with increasing VE concentration. The reaction order with respect to VE concentration was determined to be -3.52 via FTIR spectroscopy in combination with a diamond tipped attenuated total reflectance （ATR） immersion probe. The negative reaction order of VE was consistent with its retarding effect on IB polymerization by interacting with the propagating species. Molecular weight of PIB decreased with increasing polymerization temperature. The activation energy for polymerization degree （Eop） could be determined to be around -23 kJ/mol when VE concentration was 5.4 mmol/L or 6.4 mmol/L.
基金supported by the National Natural Science Foundation of China(Nos.20774008,20934001) and SINOPEC
文摘The cationic polymerizations of isobutylene （IB） coinitiated by AlCl3 were carried out in solvent mixture of nhexane/methylene dichloride （n-hex/CH2Cl2） of 60/40 V/V in the presence of ethyl benzoate （EB） at various temperatures range from -80℃ to -30℃. The effects of EB concentration （[EB]） and polymerization temperature on monomer conversion, weight-average molecular weight （Mw） and molecular weight distribution （MWD, Mw/Mn） of polyisobutylene （PIB） products were investigated. The rate of polymerization decreased while Mw of PIB products increased with increasing [EB]. The polymers with high molecular weight could be prepared in the presence of a suitable amount of EB. Significantly, the polymers with high Mw of 80.2 × 10^4 and 65.4 × 10^4 could be produced at -80℃ and -70℃ at [EB] = 0.24 × 10^3 mol/L respectively, which were much higher than that （Mw = 57.9 × 10^4） of PIB prepared at -100℃ in the absence ofEB. A simple but effective method for preparing the high molecular weight polyisobutylenes was developed in this work. It has been also found that the activation energy for propagation （Ep） depended on the polymerization temperature range in the presence of EB. An obvious inflection of the linear plots of lnXn versus 1/Tp occurred at the temperature range from -60℃ to -50℃ at four different concentrations of EB from 0.19 × 10^3 mol/L to 0.33× 10^3 tool/L, and thus the inflection temperature （Tinf） was in the range of -60℃ to -50℃. When [EB] was in the range of 0.24 × 10^3 mol/L to 0.33× 10^3 mol/L, Ep was determined to be around -12 kJ/mol when the polymerization was carried out at temperatures from -80℃ to Tinf and to be around -28 kJ/mol at temperatures from Tinf to -15℃ respectively.
基金supported by the National Natural Science Foundation of China(No.20774008)Ministry of Education(No.IRT0706).
文摘The highly reactive polyisobutylenes(PIBs) withα-double bonds(87.5 mol%) or tert-chloro(tert-Cl) groups(95 mol%) could be prepared via the cationic polymerization of isobutylene(IB) coinitiated by BF_3 or TiCl_4 respectively.The Friedel-Crafts alkylation of diphenylamine(DPA) with the highly reactive PIB withα-double bonds was further conducted under different conditions,such as at different alkylation temperature,in the mixed solvents of CH_2Cl_2/n-hexane with different solvent polarity and at DPA concentr...
基金financially supported by the Program for Excellent Talents in Beijing (No. 2010D005005000005)Beijing Municipal Education Commission research project (KM 201210017007)
文摘To improve the hydrophilicity ofpoly（styrene-b-isobutylene-b-styrene） （SIBS）, this study focuses on the synthesis of novel functional ABA triblock copolymer thermoplastic elastomers （TPEs） with polyisobutylene （PIB） as rubbery segments. The precursor poly{（styrene-co-4-[2-（tert-butyldimethylsiloxy） ethyl]styrene）-b-isobutylene-b-（styrene-co-4-[2- （tert-butyldimethylsiloxy）ethyl]styrene）}（P（St-co-TBDMES）-PIB-P（St-co-TBDMES）） triblock copolymer was first synthesized by living sequential cationic copolymerization of isobutylene （IB） with styrene （St） and 4-[2-（tert- butyldimethylsiloxy）ethyl]styrene （TBDMES） using 1,4-di（2-chloro-2-propyl）benzene （DiCumC1）/titanium tetrachloride （TiCla）/2,6-di-tert-butylpyridine （DtBP） as the initiating system. Then, P（St-co-TBDMES）-PIB-P（St-co-TBDMES） was hydrolyzed in the presence of tetra-butylammonium fluoride to yield poly{[styrene-co-4-（2-hydroxyethyl）styrene]-b- isobutylene-b-[styrene-co-4-（2-hydroxyethyl）styrene]} （P（St-co-HOES）-PIB-P（St-co-HOES）） with pendant hydroxyl groups. P（St-co-HOES）-PIB-P（St-co-HOES） used as the paclitaxel carrier was also investigated in this study. Comparing with SIBS, P（St-co-HOES）-PIB-P（St-co-HOES） has exhibited better compatibility with paclitaxel and higher release rate.
基金financially supported by the National Natural Science Foundation of China(Nos.U21A20279 and 21774119)。
文摘We report herein the cationic polymerization of isobutylene(IB)under mild conditions is realized with a new binary initiation system generated by simply mixing a Lewis super acid Al(C_(6)F_(5))_(3) and a substituted phenol(RPhOH).Polymers with medium and/or high molecular weights(M_(W)=4.9×10^(4)-27.7×10^(4) g·mol^(-1))can be obtained in toluene and temperatures from-20℃to 0℃.NMR spectrum analysis and DFT sim ulation reveals the in situ generated acidic coordinating complex Ak(C_(6)F_(5))_(3)·RPhOH is the initiating active species,which fu rther tran sformed into the ion-pair[Al(C_(6)F_(5))_(3)ORPh]^(-)[PIB]^(+)of the active intermediates upon growing IB monomers where the counter anion[Al(C_(6)F_(5))_(3)R^(O)Ph]-coordinates to the macrocation via the phenoxy oxygen.The catalyst performances are the concert effects of the steric bulkiness and electronics of the counter anion on the coordinating strength to the macrocation,which is significant to the stability of the active species.
文摘Mechanistic transformation approach has been widely applied in polymer synthesis due to its unique feature combining structurally different polymers prepared by different polymerization mechanisms.Reported methods for the formation of block and graft copolymers through mechanistic transformation involve almost all polymerizations modes.However,certain polymerization processes require extensive purification processes,which can be time-consuming and problematic.Recent developments on controlled/living polymerizations involving radical and cationic mechanisms with the ability to control molecular weight and functionality led to new pathways for mechanistic transformations.In this mini-review,we systematically discussed relevant advances in the field through three main titles namely(i)from radical to cationic mechanism,(ii)from cationic to radical mechanism,and(iii)application of specific catalyst systems for both radical and cationic polymerizations.
文摘The cationic polymerization of C4 mixed feed and isobutylene co-initiated by AlCl3xOiPr2,iBuAlC12xnOiPr2,and[emim]Cl-FeCl3xnOiPr2([emim]Cl:1-ethyl-3-methylimidazolium chloride)has been investigated.AlCl3xOiPr2 co-initiated cationic polymerization of C4 mixed feed proceeds at a lower rate than polymerization of isobutylene affording polymers with higher molecular weight.Complexes of iBuAlCh with di isopropyl ether of different compositions are more suitable co-initiators than AlCl3xOiPr2 for the synthesis of highly reactive polyisobutylene(HR PIB)from C4 mixed feed due to their higher activity in the polymerization as well as possibility to prepare polyisobutylenes with lower molecular weight and higher content of exo-olefin end groups.However,iBuA1C12 needs activating via addition of external water(initiator)and/or interaction with salts hydrates in order to increase the reaction rate and the saturated monomer conversion.[Emim]Cl-FeC13/iPr2O is a quite promising catalyst for the preparation of HR PIB with high exo-olefin end group content(>80%)and relatively low polydispersity(Mw/Mn<2.8)via cationic polymerization of C4 mixed feed.The sonication of reaction mixture in case of using[emim]Cl-FeCh allowed increasing the reaction rate and decreasing the molecular weight.
基金the financial supports from the Major State Basic Research Project(No. 2011CB606001)the Committee of Science and Technology of Zhejiang Provincea project supported by Scientific Research Fund of Ztiejiang Provincial Education Department(No.Y201121828)
文摘PEGylated poly（2-（dimethylamino）ethyl methacrylate） with comb-like architecture was synthesized by two-step polymerization. First,poly（oligo（ethylene glycol） malicate）（POEGMA） bearing pendant hydroxyl groups was prepared by direct polycondensation of oligo（ethylene glycol） and malic acid in the presence of scandium triflate as chemoselective catalyst.Then the poly（2- （dimethylamino）ethyl methacrylate） side chains were grafted from the POEGMA backbone by atom transfer radical polymerization （ATRP） after the hydroxyl groups were modified into bromo-ester form,resulting in a PEGylated cationic copolymer with branched architecture.
文摘Cationic polymer drilling fluid (CPDF) is a new water base drilling fluid in which high molecular weight (HMW) cationic polymer (CPAM) is an encapsulating and flocculating agent and organic quaternary ammonium compound (NW-1) acts as shale inhibitor. This paper describes the experimental results of cuttings recovery, particle size distribution layer spacing and Zeta potential, and discusses the inhibition of CPDF system and its major additives. The advantages of CPDF will be proved by its application in well LX-2.
文摘A star-shaped multifunctional styrene-isoprene copolymer was synthesized with n-BuLi as initiator, divinyl benzene as coupling agent, cyclobexane as solvent by living anionic polymerization. Using this polymer as grafting agent, a novel star-shaped branched polymer, containing several polyisobutylene, was prepared via cationic ~aolymerization. The star PS-b-PI and star-branched polyisobutylene were characterized by GPC, ＇HNMR and FT-IR, and the effects of different adding order and the amount of grafting agent were investigated.
文摘The cationic polymerizations of 1, 3-pentadiene were initiated by AlCl_3 in n-hexaneat 30℃ in the presence of alkyl halides, i.e., tert-butyl chloride, tert-butyl bromide andisobutyl chloride. The effects of these halides on the polymer yield, molecular weight,crosslinking reaction, cyclization and polymer microstructure, have been investigated. Twomain side reactions, crosslinking and cyclization, were suppressed and reduced by theaddition of the halides. The proportion of 1, 4 units of polymer chains was increasedby the presence of the halides, which reduced the polymer yield and the molecular weightof polymers.
基金The National Natural Sciences Foundation of China is gratefully acknowledged for its financial support (grant No. 29504032)
文摘Cationic polymerizations of 1,3-pentadiene (PD) initiated by trimethylsilyl chloride (TMSCl) incombination with TiCl_4 were carried out in n-hexane at 30℃. The yield of polymer was greatly increased bythe addition of TMSCl, indicating that the TMSCl/TiCl_4 combination is an efficient initiating system for PDcationic polymerization. However, the introduction of TMSCl gave rise to a drop in the molecular weight ofthe polymer. Kinetic results demonstrated that the polymerization initiated by TMSCl/TiCl_4 is 4.5 times fasterthan that induced by TiCl_4 alone. Various ethers were used to mediate the TMSCl/TiCl_4 initiating system.Adding diphenyl ether could increase both the yield and molecular weight of the polymer. Structural evidenceillustrates that the polymerization is indeed initiated by TiCl_4 in combination with HCl resulting fromhydrolysis by adventitious water.
文摘The cationic polymerization of 1, 3-pentadiene was initiated by the organic azide/Et_2 AlClinitiating system in CH_2Cl_2 and n-hexane. The polymerizations were also carried out in parallelwith organic chloride/Et_2AlCl and Et_2 AlCl alone for comparison. The Et_2 AlCl- induced polymer-ization gives a low yield while the polymerization initiated by organic chloride/Et_2 AlCl producesmainly insoluble product. In contrast, the polymerization with azide/Et,AlCl has a high conver-sion and the resulting polymer having a high molecular weight is totally soluble. The SEC spectraof the polymers have clearly shown the differences between these initiating systems.
基金supported by the National Natural Science Foundation of China(22306136,22176139,22425061,22406137,U2267222,U1967217,12305397)the Natural Science Foundation of Jiangsu(BK20230510)+2 种基金the Sichuan Science and Technology Program(2024YFCY0006)the New Cornerstone Science Foundation through the XPLORER PRIZEthe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Efficient segregation of TcO_(4)^(-)from high-level radioactive wastes(HLW)is critical for robust nuclear waste management and environmental protection.However,achieving deep decontamination is especially challenging in complex conditions of strong basicity,high radiation,and excessively competitive anions.Herein,we addressed the long-term challenge by modifying the imidazolium core with phenyl,trimethylphenyl,and benzyl groups in a flexible polymer chain,which constructs a precisely targeted microenvironment for selective TcO_(4)^(-)capture.This custom-engineered material(SCU-CPN-7)exhibits fast kinetics,high adsorption capacity(314.7 mg/g),excellent distribution coefficient(1.3×10^(7) mL/g),and remarkable efficiency in TcO_(4)^(-)uptake under the combining extreme conditions of strong alkalinity(1 M NaOH)and high radioactivity.More importantly,owing to the synergistic effects of the hydrophobic effect,electrostatic affinity,and p-πinteractions,SCU-CPN-7 demonstrates exceptional selectivity,capable of almost quantificationally removing TcO_(4)^(-)in the coexistence of a large excess of NO_(3)^(-)and SO_(4)^(2-),leading to an unparalleled uptake performance of TcO_(4)^(-)from simulated HLW in both batch and dynamic column separation tests.
基金supported by the National Key R&D Program of China(Nos.2023YFC3404200,2023YFC34042012023YFC3404202)+1 种基金the National Natural Science Foundation of China(No.22575253)the Beijing Natural Science Foundation(No.Z220025)。
文摘The development of synthetic hybrid biological systems integrating photosynthetic organisms with organic-abiotic functional materials holds significant promise for enhancing photosynthetic processes.The artificial regulation of the state transition between photosystem I(PSI)and photosystem II(PSII)represents a strategic and promising approach for improving the efficiency of natural photosynthesis.In this study,we demonstrate that poly(benzimidazolium-phenylthiophene)(CP4)featuring a flexible cationic backbone exhibits superior ultraviolet light-harvesting capability.The polymer CP4 enhanced PSI activity in Chlorella pyrenoidosa(C.pyrenoidosa),subsequently promoting PSII activity and augmenting overall photosynthetic performance.During light-dependent reactions,CP4 significantly accelerated photosynthetic electron transfer,resulting in a 330%increase in the production of oxygen and 93%and 96%increases in the ATP and NADPH contents,respectively.In the context of dark reactions,CP4 facilitated the conversion and utilization of light energy,leading to a 6%increase in both carbohydrate and protein contents.These findings indicate that synthetic light-harvesting polymer materials exhibit considerable application potential in the field of biomass production through enhancement of natural photosynthetic efficiency.
基金supported by the National Natural Science Foundation of China(Nos.21174096,21274100 and 21234005)the Project of International Cooperation of the Ministry of Science and Technology of China(No.2011DFA50530)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘In this work, a fluorescent monomer 2-（9-carbazolyl） ethyl vinyl ether（CEVE） was synthesized in our lab, and its photo-induced living cationic copolymerization behavior with isobutyl vinyl ether（IBVE） was investigated in detail using diphenyliodonium chloride（DPICl）/2,2-dimethoxy-2-phenylacetophenone（DMPA） and zinc bromide（Zn Br2） initiating system in dichloromethane solution at 5 °C, -5 °C, and -15 °C, respectively. The living nature of this copolymerization system was confirmed by adding fresh comonomer method after the copolymerization almost finished. In addition, the obtained fluorescent copolymer poly（IBVE-co-CEVE） has a low glass transition temperature（Tg）, below -10 °C.
基金Supported by the National Natural Science Foundation of China （No.20576117）
文摘Cationic ring opening polymerization of octamethylcyclotetrasiloxane （Da） initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher temperature was found beneficial for the reaction process while stirring intensity beyond a certain level showed no obvious effect on the reaction rate. Polymers were characterized by Fourier transform infrared, proton nuclear magnetic resonance （IH-NMR） and gel perneation chromotography. The width of molecular mass distribution was found ranging between 1.2 and 1.4, which is extraordinarlly narrow compared with that of cationic polymerizations reported elsewhere （〉 1.9）. The results were believed due to the absence of free proton and counter ion which simplifies the polymerization process and the huge steric hindrance provided by bentonite particles which keeps the propagation of polysiloxane onto the surface of bentonite particles in a much more regular way. A feasible mechanism is proposed and seems to be supported well by experiments. Additionally, from the results of α, ω-dihydrogen terminated polysiloxanes prepared, the possibility of applying this potential environmentally friendly heterogeneous catalyst in industrial polymerization of cyclosiloxanes is anticipated.
文摘Cationic polymerization of styrene has been achieved using several novel acidic initiators in room temperature ionic liquids (ILs) under mild reaction conditions to obtain polymers of low molecular weight with narrow polydispersity. Both strong protic acids such as bis(trifluoromethanesulfonyl) amide acid (HTFSA) and a moderately weak acid such as bisoxalato phosphorous acid (HBOP) have been studied as initiators. It has been observed that HTFSA initiates the polymerization rapidly even at room temperature and below, as compared to HBOP which produces a slower polymerization requiring elevated temperatures to complete. The relative difference in reactivity of the initiators as compared to the previously described HBOB initiator is discussed in terms of the difference in their proton acidity and the consequential basicity of the anions. The efficiency of different ILs as the reaction solvent is also presented.
