A nano-Li3V2（PO4）3/C powder was successfully prepared by a thermal polymerization method. The particle sizes of the intermediate product powder and the final product Li3V2（PO4）3 are all less than 200 nm. The carbo...A nano-Li3V2（PO4）3/C powder was successfully prepared by a thermal polymerization method. The particle sizes of the intermediate product powder and the final product Li3V2（PO4）3 are all less than 200 nm. The carbon is partially coated on the surface of Li3V2（PO4）3 particles and the rest exists between particles with a total carbon content of 4.6wt%. This nano-Li3V2（PO4）3/C sample shows a discharge capacity of 124 mAh/g with-out capacity fading after 100 cycles at 0.1 C in the voltage rang of 3.0-4.3 V. Excellent rate performance is also achieved with a capacity of 80 mAh/g at 20 C in 3.0-4.3 V and 100 mAh/g at 10 C in 3.0-4.8 V. This study suggests that the thermal polymerization method is suitable to synthesize nano-Li3V2（PO4）3/C materials.展开更多
Stable poly（styrene-co-sodium styrene sulfonate） （P（St-NaSS） nanoparticles with broader size distribution were synthesized by thermal emulsion polymerization without any conventional initiators and emulsifiers. T...Stable poly（styrene-co-sodium styrene sulfonate） （P（St-NaSS） nanoparticles with broader size distribution were synthesized by thermal emulsion polymerization without any conventional initiators and emulsifiers. The obtained polymer nanoparticles have higher potential, and the particle sizes have broad distribution. The stability of polymer particles originated from the addition of small amounts of ionic comonomer, NaSS, which can act as an emulsifier in somewhat. The monomer conversion could reach up to about 28 wt% in 48 h, and did not increase by further polymerization when higher polymerization temperature （120℃） was employed. This polymerization system may be give some further understand for mechanism of emulsion polymerization.展开更多
Rapid development of energy,electrical and electronic technologies has put forward higher requirements for the thermal conductivities of polymers and their composites.However,the thermal conductivity coefficient(λ)va...Rapid development of energy,electrical and electronic technologies has put forward higher requirements for the thermal conductivities of polymers and their composites.However,the thermal conductivity coefficient(λ)values of prepared thermally conductive polymer composites are still difficult to achieve expectations,which has become the bottleneck in the fields of thermally conductive polymer composites.Aimed at that,based on the accumulation of the previous research works by related researchers and our research group,this paper proposes three possible directions for breaking through the bottlenecks:(1)preparing and synthesizing intrinsically thermally conductive polymers,(2)reducing the interfacial thermal resistance in thermally conductive polymer composites,and(3)establishing suitable thermal conduction models and studying inner thermal conduction mechanism to guide experimental optimization.Also,the future development trends of the three above-mentioned directions are foreseen,hoping to provide certain basis and guidance for the preparation,researches and development of thermally conductive polymers and their composites.展开更多
A new 1D copper（Ⅱ） polymer [Cu（Hpt）（3,5-DMBA）]n has been hydrothermally synthesized with copper acetate,3-（pyridin-2-yl）-1,2,4-triazole（Hpt） and 3,5-dimethylbenzoic acid（3,5-DMBA）. It crystallizes in tric...A new 1D copper（Ⅱ） polymer [Cu（Hpt）（3,5-DMBA）]n has been hydrothermally synthesized with copper acetate,3-（pyridin-2-yl）-1,2,4-triazole（Hpt） and 3,5-dimethylbenzoic acid（3,5-DMBA）. It crystallizes in triclinic space group P1,with a = 8.1974（6）,b = 8.3280（6）,c = 12.5021（9） ？,α = 84.3320（10）,β = 71.8870（10）,γ= 65.4560（10）o,V = 737.44（9） ？~3,Dc = 1.612 g/cm3,Z = 2,F（000） = 366,GOOF = 1.035,R = 0.0298 and w R = 0.0855. The crystal structure is a one-dimensional（1-D） chain in which the Cu（Ⅱ） is five-coordinated with square pyramidal geometry. The crystal structure shows that the whole molecule consists of two copper ions bridged by two μ12-η：η0-3,5-dimethylbenzoic acid anions and two 3-（pyridin-2-yl）-1,2,4-triazole molecules. The coordination environment of Cu（Ⅱ） ion is CuO＋2N_3. The luminescence and thermal properties of the complex were investigated.展开更多
The strain and temperature sensing performance of fiber-optic Bragg gratings （FBGs） with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryo...The strain and temperature sensing performance of fiber-optic Bragg gratings （FBGs） with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryogenic field and magnetic field. The response to a temperature and strain change of coated-soft polymeric FBGs is tested by comparing with those of coated-metal FBGs. The results indicate that the coated-soft polymeric FBGs can freely detect temperature and thermal strain, their At variable magnetic field, the tested results indicate accuracy and repeatability are also discussed in detail. that the cross-coupling effects of FBGs with different matrixes are not negligible to measure electromagnetic strain during fast excitation. The present results are expected to be able to provide basis measurements on the strain of pulsed superconducting magnet/cable （cable- around-conduit conductors, cable-in-conduit conductors）, independently or utilized together with other strain measurement methods.展开更多
In recent years, the demand direction for electronic equipment has expanded into embedded and miniaturized devices. The heat radiation problem has become one of the most significant factors for hindering the developme...In recent years, the demand direction for electronic equipment has expanded into embedded and miniaturized devices. The heat radiation problem has become one of the most significant factors for hindering the development of electronic devices. Since heat radiation material is one of the important components in electronic devices, the demand for enhancing thermal conductivity is also increasingly urgent. Research on thermal conductive polymer composites has become a major direction for developing functional composites. This work reviewed the recent progress in the fabrication of thermal conductive polymer composites. Five different structures are presented, including the using of single fillers,hybrid fillers, double threshold percolation structure, segregated structure and other complex multiphase structures. Specifically, the preparation of high-performance thermal conductive polymer composites was introduced through the combination of various thermal conductive fillers.Finally, the development direction of high thermal conductive polymer composites was briefly explored.展开更多
A series of poly[（methylsilylene ethynylenephenyleneethynylene）-co-（dimethylsilylene ethynylenephenyleneethynylene）]s were synthesized by the incorporation of various ratios of methylsilylene to dimethylsilylene u...A series of poly[（methylsilylene ethynylenephenyleneethynylene）-co-（dimethylsilylene ethynylenephenyleneethynylene）]s were synthesized by the incorporation of various ratios of methylsilylene to dimethylsilylene units into the polymer chain backbone. The resultant copolymers were soluble in a variety of common organic solvents at room temperature. The copolymers were characterized by FT-IR, ^1H-NMR, GPC, rheological analysis, differential scanning calorimetry （DSC） and thermogravimetric analysis （TGA）. The results showed that the copolymers exhibited good processability and cured at low temperatures like 200℃. The curing reactions involved in hydrosilylation of Si-H and alkyne groups and the polymerization of alkynes. Td5 （5% weight loss） of the cured copolymers ranged from 629℃ to 686℃, and the decomposition residues of cured copolymers at 1000℃ ranged from 88.1% to 90.9% under nitrogen. Thermal stability of the copolymers increased with the introduction of methylsilylene traits into polymer chains. The cured copolymers were sintered at 1450℃, and the results of X-ray diffraction analysis showed that β-SIC was formed in the sintered products.展开更多
PMMA/reactive nanoclay nanocomposites were prepared by emulsion polymerization using two different reactive nanoclays. X-ray diffraction（XRD） and thermogravimetric analysis（TGA） results confirmed that the reactive...PMMA/reactive nanoclay nanocomposites were prepared by emulsion polymerization using two different reactive nanoclays. X-ray diffraction（XRD） and thermogravimetric analysis（TGA） results confirmed that the reactive nanoclays, kaolinite and montmorillonite, were obtained by the silylation reaction and the double bonds were grafted onto the edges and surfaces of the nanoclays. The presence of reactive nanoclays could increase the average molecular weights, the glass transition temperatures（Tg） and improve the thermal properties of nanocomposite. The tensile properties, Young＇s modulus, and the aging properties of the nanocomposite films were also enhanced while the light transmittance decreased. Furthermore, the nanocomposites with the reactive kaolinite presented better performances than that with the reactive montmorillonite. Finally, the action mechanism of the reactive nanoclays to the performances of PMMA/reactive nanoclay nanocomposites was proposed.展开更多
Based on the study of a new type of conducting polymer poly （3,4-ethylenedioxythiophene） （PEDOT）,we focussed on the preparation and characteristics of PEDOT nanoparticles made by reversed micelle method.Moreover,w...Based on the study of a new type of conducting polymer poly （3,4-ethylenedioxythiophene） （PEDOT）,we focussed on the preparation and characteristics of PEDOT nanoparticles made by reversed micelle method.Moreover,we deeply investigated the optical,electrical and the thermal stability of PEDOT nanoparticles.The main results are as follows： the small-sized PEDOT nanoparticles were prepared and utilized by different methods,such as ultraviolet/visible （UV-Vis） spectroscopy,Fourier-transform infrared （FT- IR） spectrum,scanning electron microscopy（SEM） and so on.The results show that the amount of oxidizer,ultrasonic treatment,polymerizing temperature and doping degree can influent morphology,electrical ability and gas sensitivity of PEDOT nanoparticles.The Bragg peaks of nanoparticles at 6.7°,12.7°,25° were observed by XRD and the better orientation of molecular chain was attributed to the effective doping of toluene-p-sulfonic acid,which also resulted in an enhancement of thermal stability of nanoparticles than conventional PEDOT.展开更多
The thermally expandable microspheres（TEMs） were prepared via suspension polymerization with acrylonitrile（AN）, methyl methacrylate（MMA） and methyl acrylate（MA） as monomers and n-hexane as the blowing agent. M...The thermally expandable microspheres（TEMs） were prepared via suspension polymerization with acrylonitrile（AN）, methyl methacrylate（MMA） and methyl acrylate（MA） as monomers and n-hexane as the blowing agent. Meanwhile, a novel type of functional and conductive thermal expandable microsphere was obtained through strongly covering the surface of microsphere by conductive polymers with the mass loading of 1.5%. The optimal conditions to prepare high foaming ratio and equally distributed microcapsules were investigated with AN-MMA-MA in the proportion of 70%/20%/10%（m/m/m）, and 25 wt% of n-hexane in oil phase. The further investigation results showed that the unexpanded TEMs were about 30 μm in diameter and the maximum expansion ratio was nearly 125 times of original volume. The polypyrrole（PPy） was smoothly coated on the surface of the TEMs and the expansion property of PPy-coated TEMs was almost the same as the uncoated TEMs. Moreover, the structure and expanding performance of TEMs and PPy-coated TEMs were characterized by scanning electron microscopy（SEM）, laser particle size analyzer and dilatometer（DIL）.展开更多
Gadolinium methacrylate（Gd（MAA）3） was synthesized by using gadolinium oxide and methacrylic acid as the starting materials and its self-polymerization kinetic was studied based on non-isothermal and isothermal ana...Gadolinium methacrylate（Gd（MAA）3） was synthesized by using gadolinium oxide and methacrylic acid as the starting materials and its self-polymerization kinetic was studied based on non-isothermal and isothermal analysis. Moreover, the monomer reactivity ratios of methyl methacrylate（MMA） and Gd（MAA）3 were evaluated by using Kelen-Tiidos method. The thermal neutron shielding properties of PMMA and poly（MMA-co-Gd（MAA）3） were calculated by MCNP program. The results show that the selfpolymerization of Gd（MAA）3 can be initiated by thermal and free radical and its activation energy is103.35 kJ/mol or 58.55 kJ/mol correspondingly in the solid state or aqueous solution. The polymerization rate,Rp,under low conversion at 65 ℃ is expressed as Rp = K[M]^（1.05）[I]^（0.60）. The reactivity ratios of r1（MMA） and r2（Gd（MAA）3） are 0.225 and 1.340, respectively. The ability of thermal neutron shielding of poly（MMA-co-Gd（MAA）3） is increased by gadolinium contents and is far better than PMMA.展开更多
The synthesis of hard-core/soft-shell calcium carbonate （CaCO3）/poly（methyl methacrylate） （PMMA） hybrid structured nanoparticles （〈100nm） by an atomized microemulsion polymerization process is reported. The p...The synthesis of hard-core/soft-shell calcium carbonate （CaCO3）/poly（methyl methacrylate） （PMMA） hybrid structured nanoparticles （〈100nm） by an atomized microemulsion polymerization process is reported. The polymer chains were anchored onto the surface of nano-CaCO3 through use of a cou- pling agent, triethoxyvinyl silane （TEVS）. Ammonium persulfate （APS）, sodium dodecyl sulfate （SDS） and n-pentanol were used as the initiator, surfactant and cosurfactant, respectively. The polymeriza- tion mechanism of the core-shell latex particles is discussed. The encapsulation of nano-CaCO3 by PMMA was confirmed using a transmission electron microscope （TEM）. The grafting percentage of the core-shell particles was investigated by thermogravimetric analysis （TGA）. The nano-CaCO3/PMMA core-shell par- ticles were characterized by Fourier transform infrared （FTIR） spectroscopy and differential scanning calorimetry （DSC）. The FTIR results revealed the existence of a strong interaction at the interface of the nano-CaCO3 particle and the PMMA, which implies that the polymer chains were successfully grafted onto the surface of the nano-CaCO3 particles through the link of the coupling agent, In addition, the TGA and DSC results indicated an enhancement of the thermal stability of the core-shell materials compared with that of the pure nano-PMMA, The nano-CaCO3/PMMA particles were blended into a polypropylene （PP） matrix by melt processing. It can also be observed using scanning electron microscopy （SEM） that the PMMA chains grafted onto the CaCO3 nanoparticles interfere with the aggregation of CaCO3 in the polymer matrix （PP matrix） and thus improve the compatibility of the CaCO3 nanoparticles with the PP matrix.展开更多
Application of flame retardants is limited because of environmental requirements. This work introduces conventional magnetic nanoparticles as a new class of nontoxic and effective flame retardant. Fe3O4 enhanced both ...Application of flame retardants is limited because of environmental requirements. This work introduces conventional magnetic nanoparticles as a new class of nontoxic and effective flame retardant. Fe3O4 enhanced both the thermal stability and flame retardant properties of a poly（vinyl alcohol） matrix. Nanoparticles were synthesized via a simple precipitation reaction without using an inert atmosphere at room temperature. The effects of different precursors and acrylamide on the morphology of the products were investigated. Nanoparticles exhibited a ferrimagnetic behavior at room temperature. To prepare the magnetic nanocomposite, Fe3O4 nanoparticles were added to the poly（vinyl alcohol）. In the presence of a flame, the magnetic nanoparticles remained together, showed resistance to dripping and protected the polymer matrix. Dispersed nanoparticles play a role of a magnetic barrier layer, which slows product volatilization and prevents flames and oxygen from reaching the sample during decomposition of the polymer.展开更多
A novel naphthyl-based self-catalyzed phthalonitrile monomer was prepared via nucleophilic displacement reaction. The structure was characterized by Fourier infrared spectrum （FT-IR） and nuclear magnetic resonance ...A novel naphthyl-based self-catalyzed phthalonitrile monomer was prepared via nucleophilic displacement reaction. The structure was characterized by Fourier infrared spectrum （FT-IR） and nuclear magnetic resonance （^1H NMR）. The polymerization mechanism was explored. Thermal properties were characterized by differential scanning calorimetry （DSC） and thermogravimetric analysis （TGA）, which demonstrated self-promoted behavior and excellent heat resistance.展开更多
文摘A nano-Li3V2（PO4）3/C powder was successfully prepared by a thermal polymerization method. The particle sizes of the intermediate product powder and the final product Li3V2（PO4）3 are all less than 200 nm. The carbon is partially coated on the surface of Li3V2（PO4）3 particles and the rest exists between particles with a total carbon content of 4.6wt%. This nano-Li3V2（PO4）3/C sample shows a discharge capacity of 124 mAh/g with-out capacity fading after 100 cycles at 0.1 C in the voltage rang of 3.0-4.3 V. Excellent rate performance is also achieved with a capacity of 80 mAh/g at 20 C in 3.0-4.3 V and 100 mAh/g at 10 C in 3.0-4.8 V. This study suggests that the thermal polymerization method is suitable to synthesize nano-Li3V2（PO4）3/C materials.
文摘Stable poly（styrene-co-sodium styrene sulfonate） （P（St-NaSS） nanoparticles with broader size distribution were synthesized by thermal emulsion polymerization without any conventional initiators and emulsifiers. The obtained polymer nanoparticles have higher potential, and the particle sizes have broad distribution. The stability of polymer particles originated from the addition of small amounts of ionic comonomer, NaSS, which can act as an emulsifier in somewhat. The monomer conversion could reach up to about 28 wt% in 48 h, and did not increase by further polymerization when higher polymerization temperature （120℃） was employed. This polymerization system may be give some further understand for mechanism of emulsion polymerization.
基金National Natural Science Foundation of China(51773169 and 51973173)Guangdong Basic and Applied Basic Research Foundation(2019B1515120093)+2 种基金Technological Base Scientific Research ProjectsNatural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province(2019JC-11)Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars.
文摘Rapid development of energy,electrical and electronic technologies has put forward higher requirements for the thermal conductivities of polymers and their composites.However,the thermal conductivity coefficient(λ)values of prepared thermally conductive polymer composites are still difficult to achieve expectations,which has become the bottleneck in the fields of thermally conductive polymer composites.Aimed at that,based on the accumulation of the previous research works by related researchers and our research group,this paper proposes three possible directions for breaking through the bottlenecks:(1)preparing and synthesizing intrinsically thermally conductive polymers,(2)reducing the interfacial thermal resistance in thermally conductive polymer composites,and(3)establishing suitable thermal conduction models and studying inner thermal conduction mechanism to guide experimental optimization.Also,the future development trends of the three above-mentioned directions are foreseen,hoping to provide certain basis and guidance for the preparation,researches and development of thermally conductive polymers and their composites.
基金Supported by the Doctoral Scientific Research Foundation of Hengyang Normal University(16D06)Key Project of Industrial Science and Technology Support of Hengyang City(2015KG23)
文摘A new 1D copper（Ⅱ） polymer [Cu（Hpt）（3,5-DMBA）]n has been hydrothermally synthesized with copper acetate,3-（pyridin-2-yl）-1,2,4-triazole（Hpt） and 3,5-dimethylbenzoic acid（3,5-DMBA）. It crystallizes in triclinic space group P1,with a = 8.1974（6）,b = 8.3280（6）,c = 12.5021（9） ？,α = 84.3320（10）,β = 71.8870（10）,γ= 65.4560（10）o,V = 737.44（9） ？~3,Dc = 1.612 g/cm3,Z = 2,F（000） = 366,GOOF = 1.035,R = 0.0298 and w R = 0.0855. The crystal structure is a one-dimensional（1-D） chain in which the Cu（Ⅱ） is five-coordinated with square pyramidal geometry. The crystal structure shows that the whole molecule consists of two copper ions bridged by two μ12-η：η0-3,5-dimethylbenzoic acid anions and two 3-（pyridin-2-yl）-1,2,4-triazole molecules. The coordination environment of Cu（Ⅱ） ion is CuO＋2N_3. The luminescence and thermal properties of the complex were investigated.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11302225,11121202 and 11327802the National Key Project of Magneto-Constrained Fusion Energy Development Program under Grant No 2013GB110002the Postdoctoral Science Foundation of China under Grant No 2014M560820
文摘The strain and temperature sensing performance of fiber-optic Bragg gratings （FBGs） with soft polymeric coating, which can be used to sense internal strain in superconducting coils, are evaluated under variable cryogenic field and magnetic field. The response to a temperature and strain change of coated-soft polymeric FBGs is tested by comparing with those of coated-metal FBGs. The results indicate that the coated-soft polymeric FBGs can freely detect temperature and thermal strain, their At variable magnetic field, the tested results indicate accuracy and repeatability are also discussed in detail. that the cross-coupling effects of FBGs with different matrixes are not negligible to measure electromagnetic strain during fast excitation. The present results are expected to be able to provide basis measurements on the strain of pulsed superconducting magnet/cable （cable- around-conduit conductors, cable-in-conduit conductors）, independently or utilized together with other strain measurement methods.
基金financially supported by Graduate Innovation Fund of Wuhan Institute of Technology,Natural Science Foundation of Hubei Province (No.2022CFB630)Open Fund of Key Laboratory of Green Preparation and Application for Functional Materials,Ministry of Education (Hubei University) (No.202105)。
文摘In recent years, the demand direction for electronic equipment has expanded into embedded and miniaturized devices. The heat radiation problem has become one of the most significant factors for hindering the development of electronic devices. Since heat radiation material is one of the important components in electronic devices, the demand for enhancing thermal conductivity is also increasingly urgent. Research on thermal conductive polymer composites has become a major direction for developing functional composites. This work reviewed the recent progress in the fabrication of thermal conductive polymer composites. Five different structures are presented, including the using of single fillers,hybrid fillers, double threshold percolation structure, segregated structure and other complex multiphase structures. Specifically, the preparation of high-performance thermal conductive polymer composites was introduced through the combination of various thermal conductive fillers.Finally, the development direction of high thermal conductive polymer composites was briefly explored.
基金supported by the National High Technology Research and Development Program of China (No.2002-305205)the Special Material Project Program of China(No.51312)Key Project of Science and Technology Foundation of China(9140-12011308)
文摘A series of poly[（methylsilylene ethynylenephenyleneethynylene）-co-（dimethylsilylene ethynylenephenyleneethynylene）]s were synthesized by the incorporation of various ratios of methylsilylene to dimethylsilylene units into the polymer chain backbone. The resultant copolymers were soluble in a variety of common organic solvents at room temperature. The copolymers were characterized by FT-IR, ^1H-NMR, GPC, rheological analysis, differential scanning calorimetry （DSC） and thermogravimetric analysis （TGA）. The results showed that the copolymers exhibited good processability and cured at low temperatures like 200℃. The curing reactions involved in hydrosilylation of Si-H and alkyne groups and the polymerization of alkynes. Td5 （5% weight loss） of the cured copolymers ranged from 629℃ to 686℃, and the decomposition residues of cured copolymers at 1000℃ ranged from 88.1% to 90.9% under nitrogen. Thermal stability of the copolymers increased with the introduction of methylsilylene traits into polymer chains. The cured copolymers were sintered at 1450℃, and the results of X-ray diffraction analysis showed that β-SIC was formed in the sintered products.
基金Funded by the National Youth Natural Science Foundation of China(No.21406247)
文摘PMMA/reactive nanoclay nanocomposites were prepared by emulsion polymerization using two different reactive nanoclays. X-ray diffraction（XRD） and thermogravimetric analysis（TGA） results confirmed that the reactive nanoclays, kaolinite and montmorillonite, were obtained by the silylation reaction and the double bonds were grafted onto the edges and surfaces of the nanoclays. The presence of reactive nanoclays could increase the average molecular weights, the glass transition temperatures（Tg） and improve the thermal properties of nanocomposite. The tensile properties, Young＇s modulus, and the aging properties of the nanocomposite films were also enhanced while the light transmittance decreased. Furthermore, the nanocomposites with the reactive kaolinite presented better performances than that with the reactive montmorillonite. Finally, the action mechanism of the reactive nanoclays to the performances of PMMA/reactive nanoclay nanocomposites was proposed.
基金Funded by the National Natural Science Foundation of China (No. 60372002)
文摘Based on the study of a new type of conducting polymer poly （3,4-ethylenedioxythiophene） （PEDOT）,we focussed on the preparation and characteristics of PEDOT nanoparticles made by reversed micelle method.Moreover,we deeply investigated the optical,electrical and the thermal stability of PEDOT nanoparticles.The main results are as follows： the small-sized PEDOT nanoparticles were prepared and utilized by different methods,such as ultraviolet/visible （UV-Vis） spectroscopy,Fourier-transform infrared （FT- IR） spectrum,scanning electron microscopy（SEM） and so on.The results show that the amount of oxidizer,ultrasonic treatment,polymerizing temperature and doping degree can influent morphology,electrical ability and gas sensitivity of PEDOT nanoparticles.The Bragg peaks of nanoparticles at 6.7°,12.7°,25° were observed by XRD and the better orientation of molecular chain was attributed to the effective doping of toluene-p-sulfonic acid,which also resulted in an enhancement of thermal stability of nanoparticles than conventional PEDOT.
基金the National Natural ScienceFoundation of China(Nos.21206171,21376010)the Project of Natural Science Foundation of Beijing(No.2152012)+1 种基金the Young Elite Teacher Project(No.27170115004/027)the Project of 2011 Collaborative Innovation for Green Printing and Publishing Technology and the Project of Beijing Municipal Commission of Educatio (No.km201410005007)for the financial supports
文摘The thermally expandable microspheres（TEMs） were prepared via suspension polymerization with acrylonitrile（AN）, methyl methacrylate（MMA） and methyl acrylate（MA） as monomers and n-hexane as the blowing agent. Meanwhile, a novel type of functional and conductive thermal expandable microsphere was obtained through strongly covering the surface of microsphere by conductive polymers with the mass loading of 1.5%. The optimal conditions to prepare high foaming ratio and equally distributed microcapsules were investigated with AN-MMA-MA in the proportion of 70%/20%/10%（m/m/m）, and 25 wt% of n-hexane in oil phase. The further investigation results showed that the unexpanded TEMs were about 30 μm in diameter and the maximum expansion ratio was nearly 125 times of original volume. The polypyrrole（PPy） was smoothly coated on the surface of the TEMs and the expansion property of PPy-coated TEMs was almost the same as the uncoated TEMs. Moreover, the structure and expanding performance of TEMs and PPy-coated TEMs were characterized by scanning electron microscopy（SEM）, laser particle size analyzer and dilatometer（DIL）.
基金Project supported by Graduate Student Research Innovation Project(KYLX_1337)
文摘Gadolinium methacrylate（Gd（MAA）3） was synthesized by using gadolinium oxide and methacrylic acid as the starting materials and its self-polymerization kinetic was studied based on non-isothermal and isothermal analysis. Moreover, the monomer reactivity ratios of methyl methacrylate（MMA） and Gd（MAA）3 were evaluated by using Kelen-Tiidos method. The thermal neutron shielding properties of PMMA and poly（MMA-co-Gd（MAA）3） were calculated by MCNP program. The results show that the selfpolymerization of Gd（MAA）3 can be initiated by thermal and free radical and its activation energy is103.35 kJ/mol or 58.55 kJ/mol correspondingly in the solid state or aqueous solution. The polymerization rate,Rp,under low conversion at 65 ℃ is expressed as Rp = K[M]^（1.05）[I]^（0.60）. The reactivity ratios of r1（MMA） and r2（Gd（MAA）3） are 0.225 and 1.340, respectively. The ability of thermal neutron shielding of poly（MMA-co-Gd（MAA）3） is increased by gadolinium contents and is far better than PMMA.
基金the University Grants Commission(UGC),New Delhi for providing the financial support[project fileNo:40-10/2011(SR),dated-July 14,2011]to conduct this research
文摘The synthesis of hard-core/soft-shell calcium carbonate （CaCO3）/poly（methyl methacrylate） （PMMA） hybrid structured nanoparticles （〈100nm） by an atomized microemulsion polymerization process is reported. The polymer chains were anchored onto the surface of nano-CaCO3 through use of a cou- pling agent, triethoxyvinyl silane （TEVS）. Ammonium persulfate （APS）, sodium dodecyl sulfate （SDS） and n-pentanol were used as the initiator, surfactant and cosurfactant, respectively. The polymeriza- tion mechanism of the core-shell latex particles is discussed. The encapsulation of nano-CaCO3 by PMMA was confirmed using a transmission electron microscope （TEM）. The grafting percentage of the core-shell particles was investigated by thermogravimetric analysis （TGA）. The nano-CaCO3/PMMA core-shell par- ticles were characterized by Fourier transform infrared （FTIR） spectroscopy and differential scanning calorimetry （DSC）. The FTIR results revealed the existence of a strong interaction at the interface of the nano-CaCO3 particle and the PMMA, which implies that the polymer chains were successfully grafted onto the surface of the nano-CaCO3 particles through the link of the coupling agent, In addition, the TGA and DSC results indicated an enhancement of the thermal stability of the core-shell materials compared with that of the pure nano-PMMA, The nano-CaCO3/PMMA particles were blended into a polypropylene （PP） matrix by melt processing. It can also be observed using scanning electron microscopy （SEM） that the PMMA chains grafted onto the CaCO3 nanoparticles interfere with the aggregation of CaCO3 in the polymer matrix （PP matrix） and thus improve the compatibility of the CaCO3 nanoparticles with the PP matrix.
文摘Application of flame retardants is limited because of environmental requirements. This work introduces conventional magnetic nanoparticles as a new class of nontoxic and effective flame retardant. Fe3O4 enhanced both the thermal stability and flame retardant properties of a poly（vinyl alcohol） matrix. Nanoparticles were synthesized via a simple precipitation reaction without using an inert atmosphere at room temperature. The effects of different precursors and acrylamide on the morphology of the products were investigated. Nanoparticles exhibited a ferrimagnetic behavior at room temperature. To prepare the magnetic nanocomposite, Fe3O4 nanoparticles were added to the poly（vinyl alcohol）. In the presence of a flame, the magnetic nanoparticles remained together, showed resistance to dripping and protected the polymer matrix. Dispersed nanoparticles play a role of a magnetic barrier layer, which slows product volatilization and prevents flames and oxygen from reaching the sample during decomposition of the polymer.
基金supported by Program for Changjiang Scholars and Innovative Research Team in University (No.IRT13060)the financial support from Natural Science Foundation of Hebei Province (No.E2014202033)
文摘A novel naphthyl-based self-catalyzed phthalonitrile monomer was prepared via nucleophilic displacement reaction. The structure was characterized by Fourier infrared spectrum （FT-IR） and nuclear magnetic resonance （^1H NMR）. The polymerization mechanism was explored. Thermal properties were characterized by differential scanning calorimetry （DSC） and thermogravimetric analysis （TGA）, which demonstrated self-promoted behavior and excellent heat resistance.
