Miniemulsion copolymerization of butyl mathacrylate （BMA） with fluoroacrylate （HFMA, TFMA） was carried out at 70 ℃ by employing potassium persulphate （KPS） as initiator. Copolymer compositions at low conversion...Miniemulsion copolymerization of butyl mathacrylate （BMA） with fluoroacrylate （HFMA, TFMA） was carried out at 70 ℃ by employing potassium persulphate （KPS） as initiator. Copolymer compositions at low conversion levels were determined by ^1H NMR spectra techniques. The reactivity ratios were evaluated by employing Kellen-Tudos （K-T） methods, which yields the apparent reactivity ratios, rBMA = 0.74, rHFMA = 0.87 and rBMA = 0.73, rTFMA = 0.75, respectively, and Q- and e-values of HFMA and TFMA were calculated by the Alfrey-Price method. The results show that HFMA and TFMA are more active than BMA, and the cross-propagation rate constant is greater than the self-propagation one in these two copolymerizations.展开更多
Synthesis and characterization of the copolymers （PAG） of α-methyl styrene （AMS） and glycidyl methacrylate （GMA） are presented. The copolymers of PAG were characterized by gel permeation chromatography （GPC）,...Synthesis and characterization of the copolymers （PAG） of α-methyl styrene （AMS） and glycidyl methacrylate （GMA） are presented. The copolymers of PAG were characterized by gel permeation chromatography （GPC）, Fourier transform infrared spectroscopy （FTIR）, nuclear magnetic resonance （^1H-NMR） and thermogravimetery （TG）. Based on the copolymer compositions determined by ^1H-NMR, the reactivity ratios of AMS and GMA were found to be 0.105 ± 0.012 and 0.883 ± 0.046 respectively by Kelen-Tudos method. TG revealed that thermal stability of the copolymers decreased with increasing the AMS content in the copolymers, which indicated that the degradation was mainly caused by the chain scission of AMS-containing structures. Under heating, the copolymers depolymerize at their weak bonds and form chain radicals, which could further initiate other chemical reactions.展开更多
For monomer reactivity ratios study, the copolymerization of D,L-3-methylglycolide (MG) with glycolide (GA) or D,L-lactide (LA) was carried out in bulk to a certain low conversion in the presence of stannous octoate a...For monomer reactivity ratios study, the copolymerization of D,L-3-methylglycolide (MG) with glycolide (GA) or D,L-lactide (LA) was carried out in bulk to a certain low conversion in the presence of stannous octoate at 140 degrees C. The copolymer compositions were determined by H-1 NMR spectroscopy. The monomer reactivity ratios were evaluated by Fineman-Ross method, Kelen-Tudos method and linear least-squares method. The monomer reactivity ratios of D,L-3-methylglycolide and glycolide or D,L-lactide are r(mg)= 0.73, r(ga)= 1.47; r(mg)= 1.71, r(la)= 0.92, respectively.展开更多
The compositions of copolymers of diethyldiallylammonium chloride （DEDAAC） with acrylamide （AM）, acrylic acid （AA） or sodium acrylic acid （NaAA） at low conversion were determined by elemental analysis, and the...The compositions of copolymers of diethyldiallylammonium chloride （DEDAAC） with acrylamide （AM）, acrylic acid （AA） or sodium acrylic acid （NaAA） at low conversion were determined by elemental analysis, and the reactivity ratios of monomers in copolymerization were obtained by Kelen-Tudos method. The results showed that the reactivity ratios rDE and rAM are 0.31 and 5.27 for DEDAAC with AM, rDE and rAA are 0.28 and 5.15 for DEDAAC with AA, and roe and rNsAA are 0.40 and 3.97 for DEDAAC with NaAA, respectively. The copolymerizations for DEDAAC with AM, AA or NaAA are non-ideal copolymerization and the products are random copolymers.展开更多
The monomer reactivity ratios of free radical copolymerization of styrene and methyl methacrylate in carbon dioxide at vapor-liquid equilibrium state (vlCO(2)) at 65 degrees C and under 7.5-8.5 MPa were measured. The ...The monomer reactivity ratios of free radical copolymerization of styrene and methyl methacrylate in carbon dioxide at vapor-liquid equilibrium state (vlCO(2)) at 65 degrees C and under 7.5-8.5 MPa were measured. The experimental results showed that, in comparison with the data in bulk copolymerization, the monomer reactivity ratio of St in vlCO(2) increased acompanied by a somewhat decrease in that of MMA. Further analysis of the sequence distributions of these copolymers by H-1-NMR spectra indicated that there was a significant bootstrap effect in this system. The local monomer concentrations in the proximity of growing free radicals, rather than the true reactivity of monomers or free radicals, were altered by the presence of vlCO(2), leading to the change in monomer reactivity ratios.展开更多
Some copolymers of 2,4-dichlorophenyl acrylate (2,4-DCPA) with styrene (St) of different teed compositions were prepared by tree radical polymerization technique using 2,2′-azobisisobutyronitrile (AIBN) as an initiat...Some copolymers of 2,4-dichlorophenyl acrylate (2,4-DCPA) with styrene (St) of different teed compositions were prepared by tree radical polymerization technique using 2,2′-azobisisobutyronitrile (AIBN) as an initiator,and the copolymers were characterized by IR spectroscopy.The copolymer composition obtained by UV-spectra led to determination of reactivity ratio by employing Fineman-Ross (F-R) and Kelen-Tudos (K-T) methods.Average molecular weight,as well as intrinsic viscosity,was obtained by vapor pressu...展开更多
The copolymerizations of methyl acrylate （MA） with different N- arylmethacrylamide （N-ArMA） were carried out in benzene solution by free radical initiation. The compositions of the copolymers were deter mined by;H...The copolymerizations of methyl acrylate （MA） with different N- arylmethacrylamide （N-ArMA） were carried out in benzene solution by free radical initiation. The compositions of the copolymers were deter mined by;H NMR method. The monomer reactivity ratios were calculated by the Fineman-Ross （F-R） method. The reactivity ratios and the activity of various N-ArMA with MA were investigated.展开更多
The reactivity ratio of monomer and the microstructure of copolymer as polycarboxylate ether(PCE)superplasticizer were investigated.Polycarboxylate ethers(PCEs)were synthesized from methyl allyl polyethylene glycol(MA...The reactivity ratio of monomer and the microstructure of copolymer as polycarboxylate ether(PCE)superplasticizer were investigated.Polycarboxylate ethers(PCEs)were synthesized from methyl allyl polyethylene glycol(MAPEG,Mw=2400 g/mol)and methacrylic acid(MAA)via aqueous free radical copolymerization in low conversion(P<20%).Gel permeation chromatography(GPC)and high performance liquid chromatography(HPLC)were used to track the residual concentration of the reactants and the amount of copolymer formed during the copolymerization.The reactivity ratios of monomers,MAPEG and MAA,were determined as r1(MAPEG)=0.0489 and r2(MAA)=1.6173,respectively,by employing the K-T and YBR methods.According to the obtained monomer reactivity results,the sequence distribution of the copolymer,the number average length of MAA in the polymerisate were found to decline with the decrease of the mole fraction of MAA in the polymerization system.As a result,the distribution of chain segments becomes narrower and the copolymer structure becomes more uniform.Therefore,uniform polymers could be obtained by slowly adding MAA monomer during copolymerization process.展开更多
The copolymerization of DL-LA and 3-BMG was carried out in bulk with stannous 2-ethythexanoate as the catalyst. A series of copolymers with pendant protected groups were obtained and characterized by H-1-NMR and GPC a...The copolymerization of DL-LA and 3-BMG was carried out in bulk with stannous 2-ethythexanoate as the catalyst. A series of copolymers with pendant protected groups were obtained and characterized by H-1-NMR and GPC analysis. The monomer reactivity ratios were evaluated by the Fineman-Ross method and the Kelen-Tudos method and found to be r(BMG)=1.96 and r(LA)=0.37, respectively.展开更多
The complexation between styrene (St) and N-phenylmaleimide (PMI) was investigated by H-1-NMR spectroscopy, and the existence of a complex was proved. The equilibrium constant of St/PMI in chloroform at 50 degrees C w...The complexation between styrene (St) and N-phenylmaleimide (PMI) was investigated by H-1-NMR spectroscopy, and the existence of a complex was proved. The equilibrium constant of St/PMI in chloroform at 50 degrees C was determined to be 0.27. New elementary propagation reactions were proposed. On the basis of the propagation elementary reactions for copolymerization with the participation of a charge-transfer complex (CTC), a method for measuring the reactivity ratios is presented. Four reactivity ratios and relative reactivities of free monomer and CTC were obtained. They are r(12) = 0.034, r(21) = 0.012, r(1C) = 0.0030, r(2C) = 0.0034, and k(1C)/k(12) = 11.34, k(2C)/k(21) = 3.42.展开更多
A series of trans-1,4-butadiene/isoprene copolymers were prepared using the catalyst system TiCl4/MgCl2-Al（i- Bu）3 with bulk precipitation technology at different temperatures. Monomers reactivity ratios were calcul...A series of trans-1,4-butadiene/isoprene copolymers were prepared using the catalyst system TiCl4/MgCl2-Al（i- Bu）3 with bulk precipitation technology at different temperatures. Monomers reactivity ratios were calculated based on the Kelen-Tiid6s （K-T） method and the Mao-Huglin （M-H） method. The influence of temperature on copolymer composition and polymerization rate was discussed in detail. The increase of reaction temperature brought the decrease of butadiene reactivity ratio rBd and supplied an effective adjustment on copolymers＇ composition distribution.展开更多
The composition and the microstructures of isoprene-methyl methacrylate copolymers havebeen quantitatively studied by 250 MHz 1H-NMR spectra. Applying two lanthanide shiftreagents, by examining the separation of reson...The composition and the microstructures of isoprene-methyl methacrylate copolymers havebeen quantitatively studied by 250 MHz 1H-NMR spectra. Applying two lanthanide shiftreagents, by examining the separation of resonance peaks of the 1,4-isoprene olefin proton,I-centred triad distributions, and even I-cectred pentad fractions are measured. It is con-firmed that there is a penultimate of effect in this free radical copolymerization and the reac-tivity ratios established corresponding to Second-order Markov chain model are r11=0.48,rMI=0.86, rMM=0.51 and rIM=0.43, respectively. The observed I-centred pentad fraetions andM-centred triad distributions agree with the above results.展开更多
The reactivity ratios of three hydrophobia monomers, FX14, LA and SA, to a hydrophilic monomer, acrylic acid (AA), were determined. For the fluorocarbon containing hydropho-bic monomer FX14, elemental analysis was ado...The reactivity ratios of three hydrophobia monomers, FX14, LA and SA, to a hydrophilic monomer, acrylic acid (AA), were determined. For the fluorocarbon containing hydropho-bic monomer FX14, elemental analysis was adopted to obtain the relative content of FX14 to AA. For two hydrocarbon monomers, 13C NMR was used. FR, KT linear method and EVM nonlinear method were applied in calculating reactivity ratios. It is found that the reactivity of LA and SA is lower than that of AA, for solution polymerization in cyclohexane. Whereas FX14 is more reactive than AA in benzene. Finally, the distribution of small amounts of these hydrophobic monomers along the polymeric chain is discussed and a random sequence is confirmed.展开更多
Discharge plasmas in air can be accompanied by ultraviolet（UV） radiation and electron impact,which can produce large numbers of reactive species such as hydroxyl radical（OH·）,oxygen radical（O·）,ozone...Discharge plasmas in air can be accompanied by ultraviolet（UV） radiation and electron impact,which can produce large numbers of reactive species such as hydroxyl radical（OH·）,oxygen radical（O·）,ozone（O3）,and nitrogen oxides（NOx）,etc.The composition and dosage of reactive species usually play an important role in the case of volatile organic compounds（VOCs） treatment with the discharge plasmas.In this paper,we propose a volume discharge setup used to purify formaldehyde in air,which is configured by a plate-to-plate dielectric barrier discharge（DBD） channel and excited by an AC high voltage source.The results show that the relative spectral-intensity from DBD cell without formaldehyde is stronger than the case with formaldehyde.The energy efficiency ratios（EERs） of both oxides yield and formaldehyde removal can be regulated by the gas flow velocity in DBD channel,and the most desirable processing effect is the gas flow velocity within the range from2.50 to 3.33 m s^-1.Moreover,the EERs of both the generated dosages of oxides（O3 and NO2） and the amount of removed formaldehyde can also be regulated by both of the applied voltage and power density loaded on the DBD cell.Additionally,the EERs of both oxides generation and formaldehyde removal present as a function of normal distribution with increasing the applied power density,and the peak of the function is appeared in the range from 273.5 to 400.0 W l-1.This work clearly demonstrates the regulation characteristic of both the formaldehyde removal and oxides yield by using volume DBD,and it is helpful in the applications of VOCs removal by using discharge plasma.展开更多
Poly(aniline- co-o-aminobenzenesulfonic acid) (PAOABSA) as a water soluble conducting polymerwas synthesized by chemical polymerization. The productivity and the room-temperature conductivity of thecopolymer were meas...Poly(aniline- co-o-aminobenzenesulfonic acid) (PAOABSA) as a water soluble conducting polymerwas synthesized by chemical polymerization. The productivity and the room-temperature conductivity of thecopolymer were measured as a function of the reaction conditions, such as reaction temperature, the ratio ofoxidant to monomer and the degree of sulfonation defined as the ratio of sulfur to nitrogen atoms(S/N). Themain results obtained are summarized as follows : (1) lower reaction temperature (at about 0℃) is favorablefor the enhancement of the room-temperature conductivity of the copolymer; (2) higher content of oxidant isunfavorable for increasing the room-temperature conductivity of the copolymer; (3) both productivity androom-temperature conductivity of the copolymer decrease with increase of the degree of sulfonation whichwas always lower than 0.5 even an excess of o-aminobenzenesulfonic acid was added, probably because thereactivity ratio of aniline (γ=2.99± 0.05) is much higher than that of o-aminobenzenesulfonic acid (γ_2 = 0.06±0.02) estimated by using Fineman-Ross method and least square method.展开更多
Two oxetane-derived monomers, 3-（2-cyano-ethoxy）methyl- and 3-（methoxy-（triethylenoxy））methyl-3＇- methyloxetane （COX and MTOX）, were prepared from 3-hydroxymethyl-3＇-methyloxetane. Their homo- and copolymeri...Two oxetane-derived monomers, 3-（2-cyano-ethoxy）methyl- and 3-（methoxy-（triethylenoxy））methyl-3＇- methyloxetane （COX and MTOX）, were prepared from 3-hydroxymethyl-3＇-methyloxetane. Their homo- and copolymerization in solution were carried out by the cationic ring-opening polymerization with BF3 · Et2O and 1,4-butanediol as co-initiator. The molecular weight and molecular weight distribution were determined using GPC so as to reveal the competition and interchange between active chain end （ACE） and activated monomer （AM） mechanism in the process. The reactivity ratios of the two monomers were calculated according to Kelen-Tudos using ^1H-NMR analysis. The influence of functional side chains in the monomers on the copolymerization behaviors was discussed in virtue of the reactivity ratio data. When doped with lithium salt LiTFSI, the ion conductivity of the homopolymer of MTOX reached 10^-3.58 S/cm at 30℃ and 10^-2.73 S/cm at 80℃, respectively, showing its potential to be used as polymer electrolyte for lithium ion battery.展开更多
The copolymerization of 2-hydroxyethyl acrylate (HEA, M//1) and methyl methacrylate (MMA, M//2) in cyclohexanone was studied. The multiple experiments of solution copolymerization with low conversion were carried out...The copolymerization of 2-hydroxyethyl acrylate (HEA, M//1) and methyl methacrylate (MMA, M//2) in cyclohexanone was studied. The multiple experiments of solution copolymerization with low conversion were carried out at two sensitive composition feed points at 60, 80, 100, 120 and 140 degree C, respectively. The composition of the copolymers was analyzed by **1H-NMR. The reactivity ratios which were estimated by the Error-in-Variable Method (EVM) of Mayo-Lewis equation were found to be r//1 equals 0.328, r//2 equals 1.781 for 60 degree C; 0.375, 1.709 for 80 degree C; 0.406, 1.654 for 100 degree C; 0.439, 1.540 for 120 degree C and 0.455, 1.400 for 140 degree C, and the 95% joint confidence intervals of the reactivity ratios were also determined. According to r//1 and r//2, Arrhenius relations and the activity energy difference between the homo- and cross-propagation were calculated. (Author abstract) 12 Refs.展开更多
Copolymerizations of L-lactide （L-LA） and ε-caprolactone （ε-CL） were conducted in bulk using magnesium octoate as a catalyst. The reactivity ratios of L-LA and ε-CL were determined to be rL=23 and rc=0.22, resp...Copolymerizations of L-lactide （L-LA） and ε-caprolactone （ε-CL） were conducted in bulk using magnesium octoate as a catalyst. The reactivity ratios of L-LA and ε-CL were determined to be rL=23 and rc=0.22, respectively. The sequence analyses of the copolymers were performed on ^13C NMR. An increase in the reaction temperature enhances the role of transesterification and the extent of randomness.展开更多
The ratio between the reactivity of HC and NOx, i.e., φ = ∑kOH＋HC, [HCi] / （kOH＋No[NO] ＋ kOH＋NO2 [NO2]）, is used to study the chemistry of HOx radicals （HOE and OH） in the marine boundary layer （MBL）. Data...The ratio between the reactivity of HC and NOx, i.e., φ = ∑kOH＋HC, [HCi] / （kOH＋No[NO] ＋ kOH＋NO2 [NO2]）, is used to study the chemistry of HOx radicals （HOE and OH） in the marine boundary layer （MBL）. Data analysis shows that HOx production and OH/HO2 ratio strongly depend on φ. The OH radical concentration presents an ascending tendency in low φ region but a de- clining one in high ∞ region, while HO2 radical increases with increasing φ under low φ conditions but appears to be nearly constant with the variation of ∞ under high φ conditions. The observed OH/HO2 ratio shows a continuous decrease with the increase of φ. Model studies are conducted to illuminate the behavior of HOx radicals in different φ regions, and the results represent general agreement with the observed variations of HOx radicals and can well explain the observed behavior of HOx radicals. This study demonstrates that φ could be used as an efficient parameter to ascertain the behavior of HOx radicals in the clean marine boundary layer.展开更多
2-Acrylamido-2-methyl-1-propanesulfonic acid （AMPS）, and maleic acid （MA） copolymerized with different feed ratios using N,N-dimethylformamide as a solvent and benzoyl peroxide （Bz2O2） as an initiator at 70℃. S...2-Acrylamido-2-methyl-1-propanesulfonic acid （AMPS）, and maleic acid （MA） copolymerized with different feed ratios using N,N-dimethylformamide as a solvent and benzoyl peroxide （Bz2O2） as an initiator at 70℃. Structure and composition of copolymers for a wide range of monomer feed were determined by elemental analysis （content of N for AMPS-units）. Monomer reactivity ratios for AMPS （M1）-MA （M2） pair were determined by the application of conventional linearization methods such as Fineman-Ross （F-R）, Kelen-Tudos（KT） and Extended Kelen-Tudos （EKT） and a nonlinear error invariable model method using a computer program RREVM. The characterizations were done by Fourier transform infrared spectroscopy （FTIR）, differential scanning calorimetry （DSC） thermal gravimetry analysis （TGA）, and and X-ray diffraction. The antimicrobial effects of polymers were also tested on various bacteria, and yeast.展开更多
基金supported by National Natural Science Foundation of China(Nos.20576117 and 20806067)China Postdoctoral Science Foundation(No.20070420230).
文摘Miniemulsion copolymerization of butyl mathacrylate （BMA） with fluoroacrylate （HFMA, TFMA） was carried out at 70 ℃ by employing potassium persulphate （KPS） as initiator. Copolymer compositions at low conversion levels were determined by ^1H NMR spectra techniques. The reactivity ratios were evaluated by employing Kellen-Tudos （K-T） methods, which yields the apparent reactivity ratios, rBMA = 0.74, rHFMA = 0.87 and rBMA = 0.73, rTFMA = 0.75, respectively, and Q- and e-values of HFMA and TFMA were calculated by the Alfrey-Price method. The results show that HFMA and TFMA are more active than BMA, and the cross-propagation rate constant is greater than the self-propagation one in these two copolymerizations.
文摘Synthesis and characterization of the copolymers （PAG） of α-methyl styrene （AMS） and glycidyl methacrylate （GMA） are presented. The copolymers of PAG were characterized by gel permeation chromatography （GPC）, Fourier transform infrared spectroscopy （FTIR）, nuclear magnetic resonance （^1H-NMR） and thermogravimetery （TG）. Based on the copolymer compositions determined by ^1H-NMR, the reactivity ratios of AMS and GMA were found to be 0.105 ± 0.012 and 0.883 ± 0.046 respectively by Kelen-Tudos method. TG revealed that thermal stability of the copolymers decreased with increasing the AMS content in the copolymers, which indicated that the degradation was mainly caused by the chain scission of AMS-containing structures. Under heating, the copolymers depolymerize at their weak bonds and form chain radicals, which could further initiate other chemical reactions.
基金This work was supported by the Key Project of the National Natural Science Foundation of China!(59833 140).
文摘For monomer reactivity ratios study, the copolymerization of D,L-3-methylglycolide (MG) with glycolide (GA) or D,L-lactide (LA) was carried out in bulk to a certain low conversion in the presence of stannous octoate at 140 degrees C. The copolymer compositions were determined by H-1 NMR spectroscopy. The monomer reactivity ratios were evaluated by Fineman-Ross method, Kelen-Tudos method and linear least-squares method. The monomer reactivity ratios of D,L-3-methylglycolide and glycolide or D,L-lactide are r(mg)= 0.73, r(ga)= 1.47; r(mg)= 1.71, r(la)= 0.92, respectively.
文摘The compositions of copolymers of diethyldiallylammonium chloride （DEDAAC） with acrylamide （AM）, acrylic acid （AA） or sodium acrylic acid （NaAA） at low conversion were determined by elemental analysis, and the reactivity ratios of monomers in copolymerization were obtained by Kelen-Tudos method. The results showed that the reactivity ratios rDE and rAM are 0.31 and 5.27 for DEDAAC with AM, rDE and rAA are 0.28 and 5.15 for DEDAAC with AA, and roe and rNsAA are 0.40 and 3.97 for DEDAAC with NaAA, respectively. The copolymerizations for DEDAAC with AM, AA or NaAA are non-ideal copolymerization and the products are random copolymers.
基金supported by the National Natural Science Foundation of China(No.20674017).
文摘The monomer reactivity ratios of free radical copolymerization of styrene and methyl methacrylate in carbon dioxide at vapor-liquid equilibrium state (vlCO(2)) at 65 degrees C and under 7.5-8.5 MPa were measured. The experimental results showed that, in comparison with the data in bulk copolymerization, the monomer reactivity ratio of St in vlCO(2) increased acompanied by a somewhat decrease in that of MMA. Further analysis of the sequence distributions of these copolymers by H-1-NMR spectra indicated that there was a significant bootstrap effect in this system. The local monomer concentrations in the proximity of growing free radicals, rather than the true reactivity of monomers or free radicals, were altered by the presence of vlCO(2), leading to the change in monomer reactivity ratios.
文摘Some copolymers of 2,4-dichlorophenyl acrylate (2,4-DCPA) with styrene (St) of different teed compositions were prepared by tree radical polymerization technique using 2,2′-azobisisobutyronitrile (AIBN) as an initiator,and the copolymers were characterized by IR spectroscopy.The copolymer composition obtained by UV-spectra led to determination of reactivity ratio by employing Fineman-Ross (F-R) and Kelen-Tudos (K-T) methods.Average molecular weight,as well as intrinsic viscosity,was obtained by vapor pressu...
文摘The copolymerizations of methyl acrylate （MA） with different N- arylmethacrylamide （N-ArMA） were carried out in benzene solution by free radical initiation. The compositions of the copolymers were deter mined by;H NMR method. The monomer reactivity ratios were calculated by the Fineman-Ross （F-R） method. The reactivity ratios and the activity of various N-ArMA with MA were investigated.
基金Funded by the Key Materials and Preparation Technology of Long-life Concrete Products Project(No.2017YFB0310002)through the National Key R&D Program。
文摘The reactivity ratio of monomer and the microstructure of copolymer as polycarboxylate ether(PCE)superplasticizer were investigated.Polycarboxylate ethers(PCEs)were synthesized from methyl allyl polyethylene glycol(MAPEG,Mw=2400 g/mol)and methacrylic acid(MAA)via aqueous free radical copolymerization in low conversion(P<20%).Gel permeation chromatography(GPC)and high performance liquid chromatography(HPLC)were used to track the residual concentration of the reactants and the amount of copolymer formed during the copolymerization.The reactivity ratios of monomers,MAPEG and MAA,were determined as r1(MAPEG)=0.0489 and r2(MAA)=1.6173,respectively,by employing the K-T and YBR methods.According to the obtained monomer reactivity results,the sequence distribution of the copolymer,the number average length of MAA in the polymerisate were found to decline with the decrease of the mole fraction of MAA in the polymerization system.As a result,the distribution of chain segments becomes narrower and the copolymer structure becomes more uniform.Therefore,uniform polymers could be obtained by slowly adding MAA monomer during copolymerization process.
基金This work was supported by the Major State Basic Research Program of China (Grant No. G1999064704).
文摘The copolymerization of DL-LA and 3-BMG was carried out in bulk with stannous 2-ethythexanoate as the catalyst. A series of copolymers with pendant protected groups were obtained and characterized by H-1-NMR and GPC analysis. The monomer reactivity ratios were evaluated by the Fineman-Ross method and the Kelen-Tudos method and found to be r(BMG)=1.96 and r(LA)=0.37, respectively.
文摘The complexation between styrene (St) and N-phenylmaleimide (PMI) was investigated by H-1-NMR spectroscopy, and the existence of a complex was proved. The equilibrium constant of St/PMI in chloroform at 50 degrees C was determined to be 0.27. New elementary propagation reactions were proposed. On the basis of the propagation elementary reactions for copolymerization with the participation of a charge-transfer complex (CTC), a method for measuring the reactivity ratios is presented. Four reactivity ratios and relative reactivities of free monomer and CTC were obtained. They are r(12) = 0.034, r(21) = 0.012, r(1C) = 0.0030, r(2C) = 0.0034, and k(1C)/k(12) = 11.34, k(2C)/k(21) = 3.42.
基金financially supported by the National Key Technology R&D Program of China(No.2011BAE26B05)the Shandong Province Natural Science Fund for Distinguished Young Scholars(No.JQ201213)+2 种基金National Natural Science Foundation of China(No.21174074)Shandong Province Science and Technology Development Plan(No.2012GGA05042)the Major Projects of Independent Innovation Achievements Transformation in Shandong Province(No.2013ZHZX1A0207)
文摘A series of trans-1,4-butadiene/isoprene copolymers were prepared using the catalyst system TiCl4/MgCl2-Al（i- Bu）3 with bulk precipitation technology at different temperatures. Monomers reactivity ratios were calculated based on the Kelen-Tiid6s （K-T） method and the Mao-Huglin （M-H） method. The influence of temperature on copolymer composition and polymerization rate was discussed in detail. The increase of reaction temperature brought the decrease of butadiene reactivity ratio rBd and supplied an effective adjustment on copolymers＇ composition distribution.
文摘The composition and the microstructures of isoprene-methyl methacrylate copolymers havebeen quantitatively studied by 250 MHz 1H-NMR spectra. Applying two lanthanide shiftreagents, by examining the separation of resonance peaks of the 1,4-isoprene olefin proton,I-centred triad distributions, and even I-cectred pentad fractions are measured. It is con-firmed that there is a penultimate of effect in this free radical copolymerization and the reac-tivity ratios established corresponding to Second-order Markov chain model are r11=0.48,rMI=0.86, rMM=0.51 and rIM=0.43, respectively. The observed I-centred pentad fraetions andM-centred triad distributions agree with the above results.
基金Project (No. 29674039) supported by the National Natural Science Foundation of China.
文摘The reactivity ratios of three hydrophobia monomers, FX14, LA and SA, to a hydrophilic monomer, acrylic acid (AA), were determined. For the fluorocarbon containing hydropho-bic monomer FX14, elemental analysis was adopted to obtain the relative content of FX14 to AA. For two hydrocarbon monomers, 13C NMR was used. FR, KT linear method and EVM nonlinear method were applied in calculating reactivity ratios. It is found that the reactivity of LA and SA is lower than that of AA, for solution polymerization in cyclohexane. Whereas FX14 is more reactive than AA in benzene. Finally, the distribution of small amounts of these hydrophobic monomers along the polymeric chain is discussed and a random sequence is confirmed.
基金partially supported by the Fundamental Research Funds for the Central Universities(2017B15214)the Research Fund of Innovation and Entrepreneurship Education Reform for Chinese Universities(16CCJG01Z004)+2 种基金the Changzhou Science and Technology Program(CJ20160027)National Natural Science Foundation of China(11274092,61705058)the Natural Science Foundation of the Jiangsu Province(BK20170302)
文摘Discharge plasmas in air can be accompanied by ultraviolet（UV） radiation and electron impact,which can produce large numbers of reactive species such as hydroxyl radical（OH·）,oxygen radical（O·）,ozone（O3）,and nitrogen oxides（NOx）,etc.The composition and dosage of reactive species usually play an important role in the case of volatile organic compounds（VOCs） treatment with the discharge plasmas.In this paper,we propose a volume discharge setup used to purify formaldehyde in air,which is configured by a plate-to-plate dielectric barrier discharge（DBD） channel and excited by an AC high voltage source.The results show that the relative spectral-intensity from DBD cell without formaldehyde is stronger than the case with formaldehyde.The energy efficiency ratios（EERs） of both oxides yield and formaldehyde removal can be regulated by the gas flow velocity in DBD channel,and the most desirable processing effect is the gas flow velocity within the range from2.50 to 3.33 m s^-1.Moreover,the EERs of both the generated dosages of oxides（O3 and NO2） and the amount of removed formaldehyde can also be regulated by both of the applied voltage and power density loaded on the DBD cell.Additionally,the EERs of both oxides generation and formaldehyde removal present as a function of normal distribution with increasing the applied power density,and the peak of the function is appeared in the range from 273.5 to 400.0 W l-1.This work clearly demonstrates the regulation characteristic of both the formaldehyde removal and oxides yield by using volume DBD,and it is helpful in the applications of VOCs removal by using discharge plasma.
基金The project was supported by National Natural Science Foundation of China, the National Advanced Materials Committee of China(NAMCC)and Chinese Academy of Sciences.
文摘Poly(aniline- co-o-aminobenzenesulfonic acid) (PAOABSA) as a water soluble conducting polymerwas synthesized by chemical polymerization. The productivity and the room-temperature conductivity of thecopolymer were measured as a function of the reaction conditions, such as reaction temperature, the ratio ofoxidant to monomer and the degree of sulfonation defined as the ratio of sulfur to nitrogen atoms(S/N). Themain results obtained are summarized as follows : (1) lower reaction temperature (at about 0℃) is favorablefor the enhancement of the room-temperature conductivity of the copolymer; (2) higher content of oxidant isunfavorable for increasing the room-temperature conductivity of the copolymer; (3) both productivity androom-temperature conductivity of the copolymer decrease with increase of the degree of sulfonation whichwas always lower than 0.5 even an excess of o-aminobenzenesulfonic acid was added, probably because thereactivity ratio of aniline (γ=2.99± 0.05) is much higher than that of o-aminobenzenesulfonic acid (γ_2 = 0.06±0.02) estimated by using Fineman-Ross method and least square method.
基金This research work was funded by National Key Projects on Basic Research and Development (The "973" Project, No. 2002CB211800).
文摘Two oxetane-derived monomers, 3-（2-cyano-ethoxy）methyl- and 3-（methoxy-（triethylenoxy））methyl-3＇- methyloxetane （COX and MTOX）, were prepared from 3-hydroxymethyl-3＇-methyloxetane. Their homo- and copolymerization in solution were carried out by the cationic ring-opening polymerization with BF3 · Et2O and 1,4-butanediol as co-initiator. The molecular weight and molecular weight distribution were determined using GPC so as to reveal the competition and interchange between active chain end （ACE） and activated monomer （AM） mechanism in the process. The reactivity ratios of the two monomers were calculated according to Kelen-Tudos using ^1H-NMR analysis. The influence of functional side chains in the monomers on the copolymerization behaviors was discussed in virtue of the reactivity ratio data. When doped with lithium salt LiTFSI, the ion conductivity of the homopolymer of MTOX reached 10^-3.58 S/cm at 30℃ and 10^-2.73 S/cm at 80℃, respectively, showing its potential to be used as polymer electrolyte for lithium ion battery.
文摘The copolymerization of 2-hydroxyethyl acrylate (HEA, M//1) and methyl methacrylate (MMA, M//2) in cyclohexanone was studied. The multiple experiments of solution copolymerization with low conversion were carried out at two sensitive composition feed points at 60, 80, 100, 120 and 140 degree C, respectively. The composition of the copolymers was analyzed by **1H-NMR. The reactivity ratios which were estimated by the Error-in-Variable Method (EVM) of Mayo-Lewis equation were found to be r//1 equals 0.328, r//2 equals 1.781 for 60 degree C; 0.375, 1.709 for 80 degree C; 0.406, 1.654 for 100 degree C; 0.439, 1.540 for 120 degree C and 0.455, 1.400 for 140 degree C, and the 95% joint confidence intervals of the reactivity ratios were also determined. According to r//1 and r//2, Arrhenius relations and the activity energy difference between the homo- and cross-propagation were calculated. (Author abstract) 12 Refs.
文摘Copolymerizations of L-lactide （L-LA） and ε-caprolactone （ε-CL） were conducted in bulk using magnesium octoate as a catalyst. The reactivity ratios of L-LA and ε-CL were determined to be rL=23 and rc=0.22, respectively. The sequence analyses of the copolymers were performed on ^13C NMR. An increase in the reaction temperature enhances the role of transesterification and the extent of randomness.
文摘The ratio between the reactivity of HC and NOx, i.e., φ = ∑kOH＋HC, [HCi] / （kOH＋No[NO] ＋ kOH＋NO2 [NO2]）, is used to study the chemistry of HOx radicals （HOE and OH） in the marine boundary layer （MBL）. Data analysis shows that HOx production and OH/HO2 ratio strongly depend on φ. The OH radical concentration presents an ascending tendency in low φ region but a de- clining one in high ∞ region, while HO2 radical increases with increasing φ under low φ conditions but appears to be nearly constant with the variation of ∞ under high φ conditions. The observed OH/HO2 ratio shows a continuous decrease with the increase of φ. Model studies are conducted to illuminate the behavior of HOx radicals in different φ regions, and the results represent general agreement with the observed variations of HOx radicals and can well explain the observed behavior of HOx radicals. This study demonstrates that φ could be used as an efficient parameter to ascertain the behavior of HOx radicals in the clean marine boundary layer.
文摘2-Acrylamido-2-methyl-1-propanesulfonic acid （AMPS）, and maleic acid （MA） copolymerized with different feed ratios using N,N-dimethylformamide as a solvent and benzoyl peroxide （Bz2O2） as an initiator at 70℃. Structure and composition of copolymers for a wide range of monomer feed were determined by elemental analysis （content of N for AMPS-units）. Monomer reactivity ratios for AMPS （M1）-MA （M2） pair were determined by the application of conventional linearization methods such as Fineman-Ross （F-R）, Kelen-Tudos（KT） and Extended Kelen-Tudos （EKT） and a nonlinear error invariable model method using a computer program RREVM. The characterizations were done by Fourier transform infrared spectroscopy （FTIR）, differential scanning calorimetry （DSC） thermal gravimetry analysis （TGA）, and and X-ray diffraction. The antimicrobial effects of polymers were also tested on various bacteria, and yeast.
