The aim of this study is to understand the relationship between the polymerization degree and cememitious activity of iron ore tailings. In light of the poor usage of iron ore tailings, stockpile samples from Tangshan...The aim of this study is to understand the relationship between the polymerization degree and cememitious activity of iron ore tailings. In light of the poor usage of iron ore tailings, stockpile samples from Tangshan were studied in terms of their ability to become cementitious materials. Compound thermal activation was used to improve the cementitious properties of the tailings, while analyzing methods, such as X-ray diffraction (XRD), infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and X-ray photoelectron spectrometer (XPS), were employed to study the changes in phase and structure under different activation conditions. The results reveal clear relationships between the binding energies of Si2p and O 1 s, polymerization degree, and cementitious activity of iron ore tailings.展开更多
The polystyrenylphosphonous acid (PSPA) of low polymerization degree was prepared with one step reaction. The reaction mechanism was changed with different initiators. For the reaction with AIBN or BPO as the initia...The polystyrenylphosphonous acid (PSPA) of low polymerization degree was prepared with one step reaction. The reaction mechanism was changed with different initiators. For the reaction with AIBN or BPO as the initiator, there are 2 or 3 series of radical reaction chains and 5 or 9 series of polystyrenyl products. The main products are PSPA without or with the fragment of the initiator H[CH(C6H5)-CH2]n-PO2H2 and C6H5CO2-[CH2CH (C6H5)]n-PO2H2 respectively.展开更多
To investigate the variation in the degree of polymerization calcium aluminium silicate hydrate(C-A-S-H)gel and its role in the evolution of the strength of waterglass slag binders,the compressive strength,hydration p...To investigate the variation in the degree of polymerization calcium aluminium silicate hydrate(C-A-S-H)gel and its role in the evolution of the strength of waterglass slag binders,the compressive strength,hydration products,degree of hydration of the slag,and the degree of polymerization of C-A-S-H gels of binders were examined.The experimental results indicate that the pH of the pore solution increased with an increase in the Na_(2)O concentration.However,mortar with an optimum compressive strength value of 81.0 MPa at 28 d was obtained when water glass modulus was 1.5.The main hydration product is a C-A-S-H gel for which the quantity and the degree of polymerization depend strongly on the Na_(2)O concentration;for a given range,both increase with increasing Na_(2)O concentration,thus yielding an enhanced strength.A further increase in the Na_(2)O concentration continuously increases the quantity of C-A-S-H gels while drastically reducing the degree of polymerization.The positive effect of the former is counteracted by the adverse effect of the latter,ultimately,leading to a decreased strength.Furthermore,we reveal that the degree of polymerization for C-A-S-H gels may be affected by pH,through a series of complex chemical reactions.展开更多
In order to study the linkage effects between degree of polymerization and frequency domain dielectric spectroscopy characteristics of oil-paper insulation, the frequency domain dielectric response test platform of oi...In order to study the linkage effects between degree of polymerization and frequency domain dielectric spectroscopy characteristics of oil-paper insulation, the frequency domain dielectric response test platform of oil-paper insulation is set up. Complex permittivity of oil-paper insulation respectively composed by new or aged oil and insulation paper with different DP are tested, and complex permittivity of oil-paper insulation respectively composed by insulation respectively composed by new oil and insulation paper with different DP and low or high moisture content are tested. The test results are analyzed, and the analysis results show that the degree of polymerization of insulation paper has an influence on complex permittivity of oil-paper insulation though influencing the distribution of moisture and acids between oil and paper.展开更多
Based on the expression of the index of coil interpenetration (i.e., the degree of coil overlap, ξb) of amorphous polymers in the bulk state proposed by Qian, the ξb was rewritten as ξb = ρb [η]θ/1.66 via Hory...Based on the expression of the index of coil interpenetration (i.e., the degree of coil overlap, ξb) of amorphous polymers in the bulk state proposed by Qian, the ξb was rewritten as ξb = ρb [η]θ/1.66 via Hory's intrinsic viscosity equation at them conditions. The ξb ofpoly (vinyl chloride) (PVC) dense membranes with different molecular weights and cellulose diacetate (CA) dense membranes prepared using different solvents were determined. The permeability, permeation coefficient (P) of nitrogen and permeation flux (J) of liquid through both membranes, respectively, was measured. P and J decreased exponentially with increasing ξb for PVC and CA membranes were revealed.展开更多
A novel acrylamide A2B2* (A = alkene, B* = alkyl chlorine) type inimer was obtained from commercially available 1,2-ethylenediamine, chloroacetyl chloride and acryloyl chloride. The as-prepared monomer can form wa...A novel acrylamide A2B2* (A = alkene, B* = alkyl chlorine) type inimer was obtained from commercially available 1,2-ethylenediamine, chloroacetyl chloride and acryloyl chloride. The as-prepared monomer can form water-soluble hyperbranched poly(N,N-ethylidene bis(N-2-chloroacetyl acrylamide))s (HPECA) through atom transfer radical polymerization/self-condensing vinyl polymerization method in the presence alkyl chlorine/CuCl/2,2-bipyridine activation system which can effectively suppress the gelation formation.1H-NMR spectra and dual detector size exclusion chromatography proved the hyperbranched structure indisputably, and the degree of branching was determined by the detailed analyses of 1H-NMR spectra. The trend of the degree of branching was in consistent with the result of Mark- Houwink exponent a. The experiment results suggested that the conversion was 67%, Mw = 13.2 x 104, Mark-Houwink a = 0.282 and the degree of branching = 64% when the reaction temperature was 120 ℃, reaction time = 168 h and N,N- ethylidene bis(N-2-chloroacetyl acrylamide):Cu(I) = 50:0.62.展开更多
Controlled preparation of brush polymers is important in the design of functional materials. In this study, poly(tert-butyl acrylate) macromonomers functionalized with norbornenyl end group(NB-PtBA) were synthesiz...Controlled preparation of brush polymers is important in the design of functional materials. In this study, poly(tert-butyl acrylate) macromonomers functionalized with norbornenyl end group(NB-PtBA) were synthesized via atom transfer radical polymerization in three different molecular weights, 2000(NB-PtBA-2k), 3000(NB-PtBA-3k), and 8000(NB-PtBA-8k). Additionally, brush polymers with PtBA as side chains were synthesized via ring-opening metathesis polymerization(ROMP). Kinetic studies on ROMP of NB-PtBA showed that there was a ceiling degree of polymerization(CDP) for the brush polymers, beyond which the polymerization of NB-PtBA was out of control. For brush polymers of P[NB-PtBA-2k] and P[NB-PtBA-3k], CDPs were estimated to be ca. 400, but the value of P[NB-PtBA-8k] was ca. 100. Therefore, the controlled ROMP of brush polymers was critical at the CDP limit with increased macromonomer molecular weight.展开更多
A kind of graphitic carbon nitride(TSC-550) with high polymerization degree and improved surface property was prepared by a new precursor of thiosemicarbazide. The sulfur motif and high nitrogen content in thiosemicar...A kind of graphitic carbon nitride(TSC-550) with high polymerization degree and improved surface property was prepared by a new precursor of thiosemicarbazide. The sulfur motif and high nitrogen content in thiosemicarbazide promoted the polymerization of thiosemicarbazide to form graphitic carbon nitride framework with high degree of polymerization, which significantly influenced the electronic structure and surface chemical properties. TSC-550 possessed a narrow bandgap of 2.19 eV that facilitated the utilization of visible light, and possessed a less positive charge, acidic surface that resulted in enhanced hydrogen adsorption ability in water solution, which promoted the H;evolution kinetics. In addition, the extended π-conjugated electronic system promoted the separation and migration of photogenerated charge carries in plane of TSC-550 framework, as well as the increasing interlayer C–N interactions in TSC-550 created conductive paths across the layers to tunnel interlayers for rapid electron transportation. As a result, TSC-550 nanosheets showed excellent photocatalytic H;production activity,the AQY achieved 36.4% at 425 nm.展开更多
Degree of branching (DB) is a crucial structure parameter of hyperbranched polymers, which can be determined by 1H NMR, quantitative 13C NMR, degradative method, etc. However, for complicated hy-perbranched polymers, ...Degree of branching (DB) is a crucial structure parameter of hyperbranched polymers, which can be determined by 1H NMR, quantitative 13C NMR, degradative method, etc. However, for complicated hy-perbranched polymers, intricate structure and severe overlap of spectral signals hinder the determina-tion of DB using traditional methods. In this work, the architecture of complicated hyperbranched polymers has been elucidated with the help of 2D NMR techniques. Using such a method, overlapped NMR signals can be well separated into a two-dimensional space, and additional structural information is also available. Correspondingly, quantitative analysis for complicated systems can be realized. De-termination of DBs for three types of complicated hyperbranched polymers synthesized from step-polymerization, self-condensation vinyl polymerization and self-condensation ring-opening po-lymerization is shown as examples.展开更多
Due to the structure characteristics of huge macromolecular size and the very low motion feature of the polymer chain which is very difficult to arrange regularly their long chain into the three dimensional space,thus...Due to the structure characteristics of huge macromolecular size and the very low motion feature of the polymer chain which is very difficult to arrange regularly their long chain into the three dimensional space,thus the polymer will incompletely crystallize except for the macroscopic single crystal of polydiacetylene polymerized by means of solid state crystalline polymerization.展开更多
基金supported by the National Natural Science Foundation of China (No.50674062)the Key Project of the Ministry of Railway of China (No.2008G031-N)the Postdoctoral Science Foundation (No.20070420354)
文摘The aim of this study is to understand the relationship between the polymerization degree and cememitious activity of iron ore tailings. In light of the poor usage of iron ore tailings, stockpile samples from Tangshan were studied in terms of their ability to become cementitious materials. Compound thermal activation was used to improve the cementitious properties of the tailings, while analyzing methods, such as X-ray diffraction (XRD), infrared spectroscopy (IR), nuclear magnetic resonance (NMR), and X-ray photoelectron spectrometer (XPS), were employed to study the changes in phase and structure under different activation conditions. The results reveal clear relationships between the binding energies of Si2p and O 1 s, polymerization degree, and cementitious activity of iron ore tailings.
文摘The polystyrenylphosphonous acid (PSPA) of low polymerization degree was prepared with one step reaction. The reaction mechanism was changed with different initiators. For the reaction with AIBN or BPO as the initiator, there are 2 or 3 series of radical reaction chains and 5 or 9 series of polystyrenyl products. The main products are PSPA without or with the fragment of the initiator H[CH(C6H5)-CH2]n-PO2H2 and C6H5CO2-[CH2CH (C6H5)]n-PO2H2 respectively.
基金Funded by the National Natural Science Foundation of China(No.51674161)the Natural Science Foundation of Shandong Province(No.ZR2019BEE075)+1 种基金the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents(No.2019RCJJ007)the Young Science and Technology Innovation Program of Shandong Province(No.2020KJD001)。
文摘To investigate the variation in the degree of polymerization calcium aluminium silicate hydrate(C-A-S-H)gel and its role in the evolution of the strength of waterglass slag binders,the compressive strength,hydration products,degree of hydration of the slag,and the degree of polymerization of C-A-S-H gels of binders were examined.The experimental results indicate that the pH of the pore solution increased with an increase in the Na_(2)O concentration.However,mortar with an optimum compressive strength value of 81.0 MPa at 28 d was obtained when water glass modulus was 1.5.The main hydration product is a C-A-S-H gel for which the quantity and the degree of polymerization depend strongly on the Na_(2)O concentration;for a given range,both increase with increasing Na_(2)O concentration,thus yielding an enhanced strength.A further increase in the Na_(2)O concentration continuously increases the quantity of C-A-S-H gels while drastically reducing the degree of polymerization.The positive effect of the former is counteracted by the adverse effect of the latter,ultimately,leading to a decreased strength.Furthermore,we reveal that the degree of polymerization for C-A-S-H gels may be affected by pH,through a series of complex chemical reactions.
文摘In order to study the linkage effects between degree of polymerization and frequency domain dielectric spectroscopy characteristics of oil-paper insulation, the frequency domain dielectric response test platform of oil-paper insulation is set up. Complex permittivity of oil-paper insulation respectively composed by new or aged oil and insulation paper with different DP are tested, and complex permittivity of oil-paper insulation respectively composed by insulation respectively composed by new oil and insulation paper with different DP and low or high moisture content are tested. The test results are analyzed, and the analysis results show that the degree of polymerization of insulation paper has an influence on complex permittivity of oil-paper insulation though influencing the distribution of moisture and acids between oil and paper.
文摘Based on the expression of the index of coil interpenetration (i.e., the degree of coil overlap, ξb) of amorphous polymers in the bulk state proposed by Qian, the ξb was rewritten as ξb = ρb [η]θ/1.66 via Hory's intrinsic viscosity equation at them conditions. The ξb ofpoly (vinyl chloride) (PVC) dense membranes with different molecular weights and cellulose diacetate (CA) dense membranes prepared using different solvents were determined. The permeability, permeation coefficient (P) of nitrogen and permeation flux (J) of liquid through both membranes, respectively, was measured. P and J decreased exponentially with increasing ξb for PVC and CA membranes were revealed.
基金financially supported by National Natural Science Foundation of China (Nos. 20904008 and 21274037)Science and Technology Foundation of Hebei Education Department (grant Nos. 2010015 and 2009307)
文摘A novel acrylamide A2B2* (A = alkene, B* = alkyl chlorine) type inimer was obtained from commercially available 1,2-ethylenediamine, chloroacetyl chloride and acryloyl chloride. The as-prepared monomer can form water-soluble hyperbranched poly(N,N-ethylidene bis(N-2-chloroacetyl acrylamide))s (HPECA) through atom transfer radical polymerization/self-condensing vinyl polymerization method in the presence alkyl chlorine/CuCl/2,2-bipyridine activation system which can effectively suppress the gelation formation.1H-NMR spectra and dual detector size exclusion chromatography proved the hyperbranched structure indisputably, and the degree of branching was determined by the detailed analyses of 1H-NMR spectra. The trend of the degree of branching was in consistent with the result of Mark- Houwink exponent a. The experiment results suggested that the conversion was 67%, Mw = 13.2 x 104, Mark-Houwink a = 0.282 and the degree of branching = 64% when the reaction temperature was 120 ℃, reaction time = 168 h and N,N- ethylidene bis(N-2-chloroacetyl acrylamide):Cu(I) = 50:0.62.
基金Supported by the National Natural Science Foundation of China(No.21574098).
文摘Controlled preparation of brush polymers is important in the design of functional materials. In this study, poly(tert-butyl acrylate) macromonomers functionalized with norbornenyl end group(NB-PtBA) were synthesized via atom transfer radical polymerization in three different molecular weights, 2000(NB-PtBA-2k), 3000(NB-PtBA-3k), and 8000(NB-PtBA-8k). Additionally, brush polymers with PtBA as side chains were synthesized via ring-opening metathesis polymerization(ROMP). Kinetic studies on ROMP of NB-PtBA showed that there was a ceiling degree of polymerization(CDP) for the brush polymers, beyond which the polymerization of NB-PtBA was out of control. For brush polymers of P[NB-PtBA-2k] and P[NB-PtBA-3k], CDPs were estimated to be ca. 400, but the value of P[NB-PtBA-8k] was ca. 100. Therefore, the controlled ROMP of brush polymers was critical at the CDP limit with increased macromonomer molecular weight.
基金supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(No.51888103)the National Natural Science Foundation of China(No.51961165103)+1 种基金the National Key Research and Development Project(No.2018YFB1502000)the Youth Innovation Team of Shaanxi Universities
文摘A kind of graphitic carbon nitride(TSC-550) with high polymerization degree and improved surface property was prepared by a new precursor of thiosemicarbazide. The sulfur motif and high nitrogen content in thiosemicarbazide promoted the polymerization of thiosemicarbazide to form graphitic carbon nitride framework with high degree of polymerization, which significantly influenced the electronic structure and surface chemical properties. TSC-550 possessed a narrow bandgap of 2.19 eV that facilitated the utilization of visible light, and possessed a less positive charge, acidic surface that resulted in enhanced hydrogen adsorption ability in water solution, which promoted the H;evolution kinetics. In addition, the extended π-conjugated electronic system promoted the separation and migration of photogenerated charge carries in plane of TSC-550 framework, as well as the increasing interlayer C–N interactions in TSC-550 created conductive paths across the layers to tunnel interlayers for rapid electron transportation. As a result, TSC-550 nanosheets showed excellent photocatalytic H;production activity,the AQY achieved 36.4% at 425 nm.
基金the National Natural Science Foundation of China (Grant Nos. 20574044, 50773037 and 50633010)NCET-06-0411+2 种基金Shanghai Rising-Star Program (Grant No. 06QA14029)Fok Ying Tung Education Foundation (Grant No. 111048)Shanghai Leading Academic Discipline Project (Grant No. B202)
文摘Degree of branching (DB) is a crucial structure parameter of hyperbranched polymers, which can be determined by 1H NMR, quantitative 13C NMR, degradative method, etc. However, for complicated hy-perbranched polymers, intricate structure and severe overlap of spectral signals hinder the determina-tion of DB using traditional methods. In this work, the architecture of complicated hyperbranched polymers has been elucidated with the help of 2D NMR techniques. Using such a method, overlapped NMR signals can be well separated into a two-dimensional space, and additional structural information is also available. Correspondingly, quantitative analysis for complicated systems can be realized. De-termination of DBs for three types of complicated hyperbranched polymers synthesized from step-polymerization, self-condensation vinyl polymerization and self-condensation ring-opening po-lymerization is shown as examples.
文摘Due to the structure characteristics of huge macromolecular size and the very low motion feature of the polymer chain which is very difficult to arrange regularly their long chain into the three dimensional space,thus the polymer will incompletely crystallize except for the macroscopic single crystal of polydiacetylene polymerized by means of solid state crystalline polymerization.