Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteri...Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteries(SSLMBs).However,PEO-based SPEs suffer from low ionic conductivity at room temperature and high interfacial resistance with the electrodes due to poor interfacial contact,seriously hindering their practical applications.As an emerging technology,in-situ polymerization process has been widely used in PEO-based SPEs because it can effectively increase Li-ion transport at the interface and improve the interfacial contact between the electrolyte and electrodes.Herein,we review recent advances in design and fabrication of in-situ polymerized PEO-based SPEs to realize enhanced performance in LMBs.The merits and current challenges of various SPEs,as well as their stabilizing strategies are presented.Furthermore,various in-situ polymerization methods(such as free radical polymerization,cationic polymerization,anionic polymerization)for the preparation of PEO-based SPEs are summarized.In addition,the application of in-situ polymerization technology in PEO-based SPEs for adjustment of the functional units and addition of different functional filler materials was systematically discussed to explore the design concepts,methods and working mechanisms.Finally,the challenges and future prospects of in-situ polymerized PEO-based SPEs for SSLMBs are also proposed.展开更多
A noncrystallizable semiaromatic polyamide copolymer(NSAP) was dissolved in molten caprolactam, and PA6/ NSAP blends were produced in-situ via the anionic ring-opening polymerization of caprolactam. The presence of ...A noncrystallizable semiaromatic polyamide copolymer(NSAP) was dissolved in molten caprolactam, and PA6/ NSAP blends were produced in-situ via the anionic ring-opening polymerization of caprolactam. The presence of a single loss tangent(tanS) peak measured by means of dynamic mechanical analysis(DMA) proves the miscibility between PA6 and NSAP in the blends. It was found that there existed drastic changes in the crystallographic form and crystallization kinetics for the in-situ blends, e.g. , when 20% NSAP was added, nearly all crystallites existed in the ,y form and the crystallization could hardly occur upon cooling even at a rate of 2.5 ℃/min. Moreover, cold crystallization appears during the subsequent heating, and its melting point is 40 ℃ lower than that of the virgin system. On the other hand, the size of the spherulites only decreases modestly. It is suggested that the introduction of irregular stiff segments originated from NSAP into PA6 macromolecule chain, which resulted from transamidation during the polymerization play a dominant role in the drastic change of crystallization kinetics and the resultant morphology of the in-situ blends.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
20 wt% polyamide 12 (PA1212) pellets were dissolved in molten caprolactam. The caprolactam was then catalyzed at 180℃ and polymerized by means of anionic ring-opening polymerization to produce in situ blends of the...20 wt% polyamide 12 (PA1212) pellets were dissolved in molten caprolactam. The caprolactam was then catalyzed at 180℃ and polymerized by means of anionic ring-opening polymerization to produce in situ blends of the resultant polyamide 6 (PA6) and PA 1212. Mechanical blends with same ingredient were prepared through melt blending on a twin-screw extruder. Scanning electron microscopy (SEM) observation revealed that contrary to the mechanical blends with small spherulites embedded in the matrix, no phase-separation existed in the in situ blends. The results of thermal analysis by differential scanning calorimetry (DSC) showed that single melting peak and crystallization peak existed for the in situ blends, while two melting and crystallization peaks appeared for the mechanical blends. The in situ blend film and the mixed blend film, both cast from a dilute formic acid solution with a concentration of 0.5 g/L, remained similar crystallization and melting behavior as above. It is proved by solution 13C-NMR analysis that transamidation took place during the in situ blending, and it is suggested that the combination of temperature increasing and the basic surrounding derived from NaOH during polymerization resulted in the occurrence of transamidation. Furthermore, it is proposed that the interchange reaction between PA 1212 and PA6 also resulted from the degradative reaction during the anionic polymerization.展开更多
A simple new method for the syntheses of a highly soluble noncross linked C 60 styrene copolymers by means of lithium camphor initiated anionic polymerization reaction is demonstrated.
A new cyclic monomer, 2-methyl-2-methocycarbonyl-5-methylene 1,3-dioxlan-4-one,wassynthesized successfully. The monomer and intermediate were characterized by ~1H NMR,^(13)C NMR, INEPT (Intensive Nuclei Enhanced by Po...A new cyclic monomer, 2-methyl-2-methocycarbonyl-5-methylene 1,3-dioxlan-4-one,wassynthesized successfully. The monomer and intermediate were characterized by ~1H NMR,^(13)C NMR, INEPT (Intensive Nuclei Enhanced by Polarization Transfer) technique, IR andelemental analysis. Anionic polymerization of the monomer was carried out in anhydrous THF at.70℃, and 9-fluorenyllithium was used as initiator. The polymer strucure was determined byIR, NMR and elemental analysis. Molecular weight of the polymer was estimated by viscositymeasurement in DMSO at 30℃.展开更多
A new cyclic monomer, 2-methyl-2-methoxycarbonyl-5-methylene-1,3-dioxolan-4-one,was synthesized successfully. The monomer and intermediate were characterized by ~1H NMR, ^(13)CNMR, INEPT(Intensive Nuclei Enhanced by P...A new cyclic monomer, 2-methyl-2-methoxycarbonyl-5-methylene-1,3-dioxolan-4-one,was synthesized successfully. The monomer and intermediate were characterized by ~1H NMR, ^(13)CNMR, INEPT(Intensive Nuclei Enhanced by Polarization Transfer) technique, IR and elementalanalysis. Anionic polymerization of the monomer was carried out in anhydrous THF at -70℃,and 9-fluorenyllithium was used as initiator. The polymer structure was determined by IR, NMRand elemental analysis. Molecular weight of the polymer was estimated by viscosity measurementin DMSO at 30℃.展开更多
Alpha-trichloroacetoxy terminated polystyrene oligomer (PS-CH2CH2OCOCCl3) and poly-(styrene-b-butadiene) oligomer [P(S-b-B)-CH2CH2OCOCCl3)] were synthesized by living anionic polymeri-zation using n-butyllithium as in...Alpha-trichloroacetoxy terminated polystyrene oligomer (PS-CH2CH2OCOCCl3) and poly-(styrene-b-butadiene) oligomer [P(S-b-B)-CH2CH2OCOCCl3)] were synthesized by living anionic polymeri-zation using n-butyllithium as initiator. Then the PS-CH2CH2OCOCCl3 (PS-Cl-3) or P(S-b-B)-CH2CH2O-COCCl3 (PSB-Cl-3) was used as the macroinitiator in the polymerization of(meth)acrylates in the presence of CuX/bpy. AB diblock and ABC triblock copolymers were prepared by the integrated living anionic polymerization (LAP)-atom transfer radical polymerization (ATRP). The structures of the PSB-Cl-3 and the P(S-b-MMA) were identified by FTIR and H-1-NMR spectrum, respectively. A new way to design block copolymers (the combination of LAP and ATRP) was developed.展开更多
Anionic polymerization of methyl methacrylate (MMA), n-butyl methacrylate (nBMA) and glycidyl methacrylate (GMA) initiated by nBuCu(NCy2)Li (1) in tetrahydrofuran (THF) at -50 degrees C to -10 degrees C was investigat...Anionic polymerization of methyl methacrylate (MMA), n-butyl methacrylate (nBMA) and glycidyl methacrylate (GMA) initiated by nBuCu(NCy2)Li (1) in tetrahydrofuran (THF) at -50 degrees C to -10 degrees C was investigated. It was found that the polymerization of MMA and nBMA initiated by 1 proceeded quantitatively in THF to afford PMMA and PBMA with polydispersity index 1.15-1.30 and nearly 100% initiator efficiencies at -10 degrees C. The molecular weights increased linearly with the ratio of [monomer]/[1]. However, a post-polymerization experiment carried out on this system revealed a double polymer peak by GPC when fresh monomer was added after an interval of 10 min. Polymerization of styrene could be initiated by 1, but the initiator efficiency was low.展开更多
The initiation reactions in the anionic non-equilibrium polymerization of octamethy- lcyclotetrasiloxane (D4) initiated by silazyllithiums were investigated. It was found that the structure of the substituents on the...The initiation reactions in the anionic non-equilibrium polymerization of octamethy- lcyclotetrasiloxane (D4) initiated by silazyllithiums were investigated. It was found that the structure of the substituents on the Si atom had great influences on the initiation activity of silazyllithiums.展开更多
Some chiral binaphthyl crown ethers were synthesized. The anionic polymerization of methyl methacrylate (MMA) was carried out in the presence of t-BuOK, Ph2CHK or Ph2CHNa (RM), and RM coordination initiator by using c...Some chiral binaphthyl crown ethers were synthesized. The anionic polymerization of methyl methacrylate (MMA) was carried out in the presence of t-BuOK, Ph2CHK or Ph2CHNa (RM), and RM coordination initiator by using chiral binaphthyl crown ethers as ligands, respectively. The results showed that in the former case the PMMA obtained has mainly isotactic structure but without optical activity, while in the later case the PMMA produced predominately has syndiotactic structure also without optical activity.展开更多
The kinetic study of the anionic polymerization of isoprens is carried out in tetrahy-drofuran(THF), using n-BuLi as initiator. Kinetic parameters are obtained, which comprise chain propagation rate constant, kp, and ...The kinetic study of the anionic polymerization of isoprens is carried out in tetrahy-drofuran(THF), using n-BuLi as initiator. Kinetic parameters are obtained, which comprise chain propagation rate constant, kp, and partial rate constants, k3 and k4 +k5, propagstion orders with respect to monomer and active species concentration, α and β, real activation energy, E, as well as partial activation energies, E3 and E4+5 and so on. The relationship between the microstruc-ture of polyisoprene and the ratio of [THF]/[n-BuLi] has been investigated. On the basis of the studies mentioned above, a resonable mechanism of the anionic polynerization of isoprene is THF is proposed.展开更多
The function of solid electrolytes and the composition of solid electrolyte interphase(SEI)are highly significant for inhibiting the growth of Li dendrites.Herein,we report an in-situ interfacial passivation combined ...The function of solid electrolytes and the composition of solid electrolyte interphase(SEI)are highly significant for inhibiting the growth of Li dendrites.Herein,we report an in-situ interfacial passivation combined with self-adaptability strategy to reinforce Li_(0.33)La_(0.557)TiO_(3)(LLTO)-based solid-state batteries.Specifically,a functional SEI enriched with LiF/Li_(3)PO_(4) is formed by in-situ electrochemical conversion,which is greatly beneficial to improving interface compatibility and enhancing ion transport.While the polarized dielectric BaTiO_(3)-polyamic acid(BTO-PAA,BP)film greatly improves the Li-ion transport kinetics and homogenizes the Li deposition.As expected,the resulting electrolyte offers considerable ionic conductivity at room temperature(4.3 x 10~(-4)S cm^(-1))and appreciable electrochemical decomposition voltage(5.23 V)after electrochemical passivation.For Li-LiFePO_(4) batteries,it shows a high specific capacity of 153 mA h g^(-1)at 0.2C after 100 cycles and a long-term durability of 115 mA h g^(-1)at 1.0 C after 800 cycles.Additionally,a stable Li plating/stripping can be achieved for more than 900 h at 0.5 mA cm^(-2).The stabilization mechanisms are elucidated by ex-situ XRD,ex-situ XPS,and ex-situ FTIR techniques,and the corresponding results reveal that the interfacial passivation combined with polarization effect is an effective strategy for improving the electrochemical performance.The present study provides a deeper insight into the dynamic adjustment of electrode-electrolyte interfacial for solid-state lithium batteries.展开更多
In the present paper,a mixed solvent method is applied to the trimethylsilylation of silicate glass,and the polymerization degree and its distribution of silicate anions in the silicate glass are measured by means of ...In the present paper,a mixed solvent method is applied to the trimethylsilylation of silicate glass,and the polymerization degree and its distribution of silicate anions in the silicate glass are measured by means of the analyses of gas chromatography-mass spectrography.展开更多
The polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by metavanadate-containing anion exchange resin (PV)-thiourea (TU) redox system at 20—40℃. has been investigated. The overall rate of polymer...The polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by metavanadate-containing anion exchange resin (PV)-thiourea (TU) redox system at 20—40℃. has been investigated. The overall rate of polymerization (R_p) is given byR_p=1.92×10~4e^(-6.860/RT) [AN]^(1.2) [PV]^(0.44) [TU]^(1.0)[HNO_3]^(1.0)The kinetic parameters differed from those of V^(5+)-TU system indicated that the generation of the primary radicals is mainly a difffusion-controlled reaction. The effect of macromolecular field arisen from the polymer matrix exerts a great influence on the polymerization process.展开更多
Polypropylene/montmorillonite (PP/MMT)nanocomposites were prepared by in-situ polymerization using aMMT/MgCl_2/TiCl_4-EB Ziegler-Natta catalyst activated by triethylaluminum(TEA). The enlarged layer spacing of MMT was...Polypropylene/montmorillonite (PP/MMT)nanocomposites were prepared by in-situ polymerization using aMMT/MgCl_2/TiCl_4-EB Ziegler-Natta catalyst activated by triethylaluminum(TEA). The enlarged layer spacing of MMT wasconfirmed by X-ray wide angle diffraction (WAXD), demonstrating that MMT were intercalated by the catalyst components.X-ray photoelectron spectrometry (XPS) analysis proved that TiCl_4 was mainly supported on MgCl_2 instead of on the surfaceof MMT The exfoliated structure of MMT layers in the PP matrix of PP/MMT composites was demonstrated by WAXDpatterns and transmission electron microscopy (TEM) observation. The higher glass transition temperature and higher storage modulus of the PP/MMT composites in comparison with pure PP were revealed by dynamic mechanical analysis (DMA).展开更多
Polysulfonamide/zinc oxide(PSA/ZnO) nanocomposite films with w(ZnO)=0.5% were prepared by in-situ polymerization based on 4,4′-diaminodiphenylsulfone and terephthaloyl chloride in the common solvent N,N-Dimethylaceta...Polysulfonamide/zinc oxide(PSA/ZnO) nanocomposite films with w(ZnO)=0.5% were prepared by in-situ polymerization based on 4,4′-diaminodiphenylsulfone and terephthaloyl chloride in the common solvent N,N-Dimethylacetamide(DMAc). Atomic force microscopy (AFM) was employed to observe the microstructure of the composite film. The thermal property was investigated by TGA and mechanical property was characterized by DXLL-1000 electromechanical material testing machine. The results showed that the breaking strength of the film containing 0.5% ZnO was great enhanced. The average size of ZnO particles was below 100 nm. The introduction of ZnO as nano filler in PSA react as UV shield effect and make the composite mechanical property improved.展开更多
Conductive polymer composites based on crystalline polymer matrix have been prepared by using an in-situ polymerization process of pyrrole in amorphous poly (ethylene terephthalate) (PET) film. The DSC and WAXD me...Conductive polymer composites based on crystalline polymer matrix have been prepared by using an in-situ polymerization process of pyrrole in amorphous poly (ethylene terephthalate) (PET) film. The DSC and WAXD measurement and SEM observation show that liquid-induced crystallization of PET matrix has occurred during the preparation of composite films. Depending upon the equilibrium degree of swelling and crystallinity, the limited depth of penetration of pyrrole molecules results in a skin-core structure of the composite film. The skin layer containing charge transfer intercalated polypyrrole has a surface resistance of 3.5×10;Ω. Rigid and heat-resistant polypyrrole molecules formed in PET film increase the tensile modulus and, especially, the rigidity of PET at elevated temperatures. However, they decrease the tensile strength and elongation at break, and impair the thermal ductility of PET.展开更多
Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but challenging.Herein,a novel PC of the...Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but challenging.Herein,a novel PC of the persistent radical anion(PRA)(possessing the properties of both radical and anion) was developed for NIR photocontrolled reversible additionfragmentation chain transfer(RAFT) polymerization,enabling successful polymerization while gaining a deep insight into the mechanism of photo-induced electron transfer RAFT(PET-RAFT) polymerization.Different from the conventional and wellaccepted reductive quenching(RQ) pathway,in which the radical anion intermediates of PCs(PCs^(·-)) must be generated in an excited state(ES),here,the PRA(3,4,9,10-perylenetetracarboxylic dianhydride radical anion(PTCDA^(·-))) could generate conveniently in situ in the ground state(GS) and subsequently serve as highly efficient PC in the NIR region(740–850 nm).The successful implementation of this strategy elucidates the peculiar role played by light and the real way of electron transfer behaviors.In fact,the transfer of a single electron from PRA to chain transfer agent(CTA) and cleavage of the C–S bonds is a process from ES to GS,rather than always from GS(PCs^(·-)) to GS(CTA) in the RQ pathway as is well known to all.In addition,the excellent spatial-temporal control and powerful penetration ability of the NIR light were also confirmed by this PRAcatalyzed polymerization system.展开更多
This work focused on the anionic polymerization of octamethylcyclotetrasiloxane (D-4, D = Me2SiO2/2) initiated by a new kind of initiator hexamethydisilazyl-lithium (MMNLi). Si-29-NMR spectroscopy and gas chromatograp...This work focused on the anionic polymerization of octamethylcyclotetrasiloxane (D-4, D = Me2SiO2/2) initiated by a new kind of initiator hexamethydisilazyl-lithium (MMNLi). Si-29-NMR spectroscopy and gas chromatography (GC) were used to characterize the polymerization products. The process was accelerated by adding a small amount of high activity monomer D-3 and by raising the polymerization temperature. At the end of polymerization more than 95% of the monomer was converted to polymer and only a very small amount of D-4 and D-5 remained in the polymers.展开更多
基金This work was supported by the Major Science and Technology Projects of Henan Province(221100230200)the National Key Research and Development Program of China(2020YFB1713500)Open Fund of State Key Laboratory of Advanced Refractories(No.SKLAR202210).
文摘Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteries(SSLMBs).However,PEO-based SPEs suffer from low ionic conductivity at room temperature and high interfacial resistance with the electrodes due to poor interfacial contact,seriously hindering their practical applications.As an emerging technology,in-situ polymerization process has been widely used in PEO-based SPEs because it can effectively increase Li-ion transport at the interface and improve the interfacial contact between the electrolyte and electrodes.Herein,we review recent advances in design and fabrication of in-situ polymerized PEO-based SPEs to realize enhanced performance in LMBs.The merits and current challenges of various SPEs,as well as their stabilizing strategies are presented.Furthermore,various in-situ polymerization methods(such as free radical polymerization,cationic polymerization,anionic polymerization)for the preparation of PEO-based SPEs are summarized.In addition,the application of in-situ polymerization technology in PEO-based SPEs for adjustment of the functional units and addition of different functional filler materials was systematically discussed to explore the design concepts,methods and working mechanisms.Finally,the challenges and future prospects of in-situ polymerized PEO-based SPEs for SSLMBs are also proposed.
基金Supported by the National Natural Science Foundation of China(No50373037)
文摘A noncrystallizable semiaromatic polyamide copolymer(NSAP) was dissolved in molten caprolactam, and PA6/ NSAP blends were produced in-situ via the anionic ring-opening polymerization of caprolactam. The presence of a single loss tangent(tanS) peak measured by means of dynamic mechanical analysis(DMA) proves the miscibility between PA6 and NSAP in the blends. It was found that there existed drastic changes in the crystallographic form and crystallization kinetics for the in-situ blends, e.g. , when 20% NSAP was added, nearly all crystallites existed in the ,y form and the crystallization could hardly occur upon cooling even at a rate of 2.5 ℃/min. Moreover, cold crystallization appears during the subsequent heating, and its melting point is 40 ℃ lower than that of the virgin system. On the other hand, the size of the spherulites only decreases modestly. It is suggested that the introduction of irregular stiff segments originated from NSAP into PA6 macromolecule chain, which resulted from transamidation during the polymerization play a dominant role in the drastic change of crystallization kinetics and the resultant morphology of the in-situ blends.
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.
基金This work was financially supported by the National Natural Science Foundation of China(No.50373037).
文摘20 wt% polyamide 12 (PA1212) pellets were dissolved in molten caprolactam. The caprolactam was then catalyzed at 180℃ and polymerized by means of anionic ring-opening polymerization to produce in situ blends of the resultant polyamide 6 (PA6) and PA 1212. Mechanical blends with same ingredient were prepared through melt blending on a twin-screw extruder. Scanning electron microscopy (SEM) observation revealed that contrary to the mechanical blends with small spherulites embedded in the matrix, no phase-separation existed in the in situ blends. The results of thermal analysis by differential scanning calorimetry (DSC) showed that single melting peak and crystallization peak existed for the in situ blends, while two melting and crystallization peaks appeared for the mechanical blends. The in situ blend film and the mixed blend film, both cast from a dilute formic acid solution with a concentration of 0.5 g/L, remained similar crystallization and melting behavior as above. It is proved by solution 13C-NMR analysis that transamidation took place during the in situ blending, and it is suggested that the combination of temperature increasing and the basic surrounding derived from NaOH during polymerization resulted in the occurrence of transamidation. Furthermore, it is proposed that the interchange reaction between PA 1212 and PA6 also resulted from the degradative reaction during the anionic polymerization.
文摘A simple new method for the syntheses of a highly soluble noncross linked C 60 styrene copolymers by means of lithium camphor initiated anionic polymerization reaction is demonstrated.
文摘A new cyclic monomer, 2-methyl-2-methocycarbonyl-5-methylene 1,3-dioxlan-4-one,wassynthesized successfully. The monomer and intermediate were characterized by ~1H NMR,^(13)C NMR, INEPT (Intensive Nuclei Enhanced by Polarization Transfer) technique, IR andelemental analysis. Anionic polymerization of the monomer was carried out in anhydrous THF at.70℃, and 9-fluorenyllithium was used as initiator. The polymer strucure was determined byIR, NMR and elemental analysis. Molecular weight of the polymer was estimated by viscositymeasurement in DMSO at 30℃.
文摘A new cyclic monomer, 2-methyl-2-methoxycarbonyl-5-methylene-1,3-dioxolan-4-one,was synthesized successfully. The monomer and intermediate were characterized by ~1H NMR, ^(13)CNMR, INEPT(Intensive Nuclei Enhanced by Polarization Transfer) technique, IR and elementalanalysis. Anionic polymerization of the monomer was carried out in anhydrous THF at -70℃,and 9-fluorenyllithium was used as initiator. The polymer structure was determined by IR, NMRand elemental analysis. Molecular weight of the polymer was estimated by viscosity measurementin DMSO at 30℃.
基金The Project is supported by the National Natural Science Foundation of China (Grant No. 29634010-2), Shanghai Education Development Foundation Shuguang Program (Project SG97008) and Research Institute of Beijing Yanshan Petrochemical Corporation.
文摘Alpha-trichloroacetoxy terminated polystyrene oligomer (PS-CH2CH2OCOCCl3) and poly-(styrene-b-butadiene) oligomer [P(S-b-B)-CH2CH2OCOCCl3)] were synthesized by living anionic polymeri-zation using n-butyllithium as initiator. Then the PS-CH2CH2OCOCCl3 (PS-Cl-3) or P(S-b-B)-CH2CH2O-COCCl3 (PSB-Cl-3) was used as the macroinitiator in the polymerization of(meth)acrylates in the presence of CuX/bpy. AB diblock and ABC triblock copolymers were prepared by the integrated living anionic polymerization (LAP)-atom transfer radical polymerization (ATRP). The structures of the PSB-Cl-3 and the P(S-b-MMA) were identified by FTIR and H-1-NMR spectrum, respectively. A new way to design block copolymers (the combination of LAP and ATRP) was developed.
基金supported by the National Natural Science Foundation of China(No.20374005)China Petroleum &Chemical Corporation.
文摘Anionic polymerization of methyl methacrylate (MMA), n-butyl methacrylate (nBMA) and glycidyl methacrylate (GMA) initiated by nBuCu(NCy2)Li (1) in tetrahydrofuran (THF) at -50 degrees C to -10 degrees C was investigated. It was found that the polymerization of MMA and nBMA initiated by 1 proceeded quantitatively in THF to afford PMMA and PBMA with polydispersity index 1.15-1.30 and nearly 100% initiator efficiencies at -10 degrees C. The molecular weights increased linearly with the ratio of [monomer]/[1]. However, a post-polymerization experiment carried out on this system revealed a double polymer peak by GPC when fresh monomer was added after an interval of 10 min. Polymerization of styrene could be initiated by 1, but the initiator efficiency was low.
文摘The initiation reactions in the anionic non-equilibrium polymerization of octamethy- lcyclotetrasiloxane (D4) initiated by silazyllithiums were investigated. It was found that the structure of the substituents on the Si atom had great influences on the initiation activity of silazyllithiums.
基金This work was supported by the National Natural Science Foundation of China (No. 29974034).
文摘Some chiral binaphthyl crown ethers were synthesized. The anionic polymerization of methyl methacrylate (MMA) was carried out in the presence of t-BuOK, Ph2CHK or Ph2CHNa (RM), and RM coordination initiator by using chiral binaphthyl crown ethers as ligands, respectively. The results showed that in the former case the PMMA obtained has mainly isotactic structure but without optical activity, while in the later case the PMMA produced predominately has syndiotactic structure also without optical activity.
文摘The kinetic study of the anionic polymerization of isoprens is carried out in tetrahy-drofuran(THF), using n-BuLi as initiator. Kinetic parameters are obtained, which comprise chain propagation rate constant, kp, and partial rate constants, k3 and k4 +k5, propagstion orders with respect to monomer and active species concentration, α and β, real activation energy, E, as well as partial activation energies, E3 and E4+5 and so on. The relationship between the microstruc-ture of polyisoprene and the ratio of [THF]/[n-BuLi] has been investigated. On the basis of the studies mentioned above, a resonable mechanism of the anionic polynerization of isoprene is THF is proposed.
基金financially supported by the National Natural Science Foundation of China (51971080)the Shenzhen Bureau of Science,Technology and Innovation Commission (GXWD20201230155427003-20200730151200003 and JSGG20200914113601003)。
文摘The function of solid electrolytes and the composition of solid electrolyte interphase(SEI)are highly significant for inhibiting the growth of Li dendrites.Herein,we report an in-situ interfacial passivation combined with self-adaptability strategy to reinforce Li_(0.33)La_(0.557)TiO_(3)(LLTO)-based solid-state batteries.Specifically,a functional SEI enriched with LiF/Li_(3)PO_(4) is formed by in-situ electrochemical conversion,which is greatly beneficial to improving interface compatibility and enhancing ion transport.While the polarized dielectric BaTiO_(3)-polyamic acid(BTO-PAA,BP)film greatly improves the Li-ion transport kinetics and homogenizes the Li deposition.As expected,the resulting electrolyte offers considerable ionic conductivity at room temperature(4.3 x 10~(-4)S cm^(-1))and appreciable electrochemical decomposition voltage(5.23 V)after electrochemical passivation.For Li-LiFePO_(4) batteries,it shows a high specific capacity of 153 mA h g^(-1)at 0.2C after 100 cycles and a long-term durability of 115 mA h g^(-1)at 1.0 C after 800 cycles.Additionally,a stable Li plating/stripping can be achieved for more than 900 h at 0.5 mA cm^(-2).The stabilization mechanisms are elucidated by ex-situ XRD,ex-situ XPS,and ex-situ FTIR techniques,and the corresponding results reveal that the interfacial passivation combined with polarization effect is an effective strategy for improving the electrochemical performance.The present study provides a deeper insight into the dynamic adjustment of electrode-electrolyte interfacial for solid-state lithium batteries.
文摘In the present paper,a mixed solvent method is applied to the trimethylsilylation of silicate glass,and the polymerization degree and its distribution of silicate anions in the silicate glass are measured by means of the analyses of gas chromatography-mass spectrography.
文摘The polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by metavanadate-containing anion exchange resin (PV)-thiourea (TU) redox system at 20—40℃. has been investigated. The overall rate of polymerization (R_p) is given byR_p=1.92×10~4e^(-6.860/RT) [AN]^(1.2) [PV]^(0.44) [TU]^(1.0)[HNO_3]^(1.0)The kinetic parameters differed from those of V^(5+)-TU system indicated that the generation of the primary radicals is mainly a difffusion-controlled reaction. The effect of macromolecular field arisen from the polymer matrix exerts a great influence on the polymerization process.
文摘Polypropylene/montmorillonite (PP/MMT)nanocomposites were prepared by in-situ polymerization using aMMT/MgCl_2/TiCl_4-EB Ziegler-Natta catalyst activated by triethylaluminum(TEA). The enlarged layer spacing of MMT wasconfirmed by X-ray wide angle diffraction (WAXD), demonstrating that MMT were intercalated by the catalyst components.X-ray photoelectron spectrometry (XPS) analysis proved that TiCl_4 was mainly supported on MgCl_2 instead of on the surfaceof MMT The exfoliated structure of MMT layers in the PP matrix of PP/MMT composites was demonstrated by WAXDpatterns and transmission electron microscopy (TEM) observation. The higher glass transition temperature and higher storage modulus of the PP/MMT composites in comparison with pure PP were revealed by dynamic mechanical analysis (DMA).
基金Education Commission of Shanghai (No04AB19)Science and Technology Commission of Shanghai Municipal Government(Nano Founds No 0452NM051)
文摘Polysulfonamide/zinc oxide(PSA/ZnO) nanocomposite films with w(ZnO)=0.5% were prepared by in-situ polymerization based on 4,4′-diaminodiphenylsulfone and terephthaloyl chloride in the common solvent N,N-Dimethylacetamide(DMAc). Atomic force microscopy (AFM) was employed to observe the microstructure of the composite film. The thermal property was investigated by TGA and mechanical property was characterized by DXLL-1000 electromechanical material testing machine. The results showed that the breaking strength of the film containing 0.5% ZnO was great enhanced. The average size of ZnO particles was below 100 nm. The introduction of ZnO as nano filler in PSA react as UV shield effect and make the composite mechanical property improved.
文摘Conductive polymer composites based on crystalline polymer matrix have been prepared by using an in-situ polymerization process of pyrrole in amorphous poly (ethylene terephthalate) (PET) film. The DSC and WAXD measurement and SEM observation show that liquid-induced crystallization of PET matrix has occurred during the preparation of composite films. Depending upon the equilibrium degree of swelling and crystallinity, the limited depth of penetration of pyrrole molecules results in a skin-core structure of the composite film. The skin layer containing charge transfer intercalated polypyrrole has a surface resistance of 3.5×10;Ω. Rigid and heat-resistant polypyrrole molecules formed in PET film increase the tensile modulus and, especially, the rigidity of PET at elevated temperatures. However, they decrease the tensile strength and elongation at break, and impair the thermal ductility of PET.
基金supported by the National Natural Science Foundation of China (21871201)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)。
文摘Developing a new type of photocatalyst(PC) and catalytic mechanism for near-infrared(NIR) photocontrolled reversibledeactivation radical polymerization(RDRP) system is charming but challenging.Herein,a novel PC of the persistent radical anion(PRA)(possessing the properties of both radical and anion) was developed for NIR photocontrolled reversible additionfragmentation chain transfer(RAFT) polymerization,enabling successful polymerization while gaining a deep insight into the mechanism of photo-induced electron transfer RAFT(PET-RAFT) polymerization.Different from the conventional and wellaccepted reductive quenching(RQ) pathway,in which the radical anion intermediates of PCs(PCs^(·-)) must be generated in an excited state(ES),here,the PRA(3,4,9,10-perylenetetracarboxylic dianhydride radical anion(PTCDA^(·-))) could generate conveniently in situ in the ground state(GS) and subsequently serve as highly efficient PC in the NIR region(740–850 nm).The successful implementation of this strategy elucidates the peculiar role played by light and the real way of electron transfer behaviors.In fact,the transfer of a single electron from PRA to chain transfer agent(CTA) and cleavage of the C–S bonds is a process from ES to GS,rather than always from GS(PCs^(·-)) to GS(CTA) in the RQ pathway as is well known to all.In addition,the excellent spatial-temporal control and powerful penetration ability of the NIR light were also confirmed by this PRAcatalyzed polymerization system.
文摘This work focused on the anionic polymerization of octamethylcyclotetrasiloxane (D-4, D = Me2SiO2/2) initiated by a new kind of initiator hexamethydisilazyl-lithium (MMNLi). Si-29-NMR spectroscopy and gas chromatography (GC) were used to characterize the polymerization products. The process was accelerated by adding a small amount of high activity monomer D-3 and by raising the polymerization temperature. At the end of polymerization more than 95% of the monomer was converted to polymer and only a very small amount of D-4 and D-5 remained in the polymers.