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
Crosslinked poly(methyl methacrylate) and polystyrene with barium dimethacrylate [Ba(MA)_2] as crosslinking agent have been synthesized. The relationship between X-ray absorbability and the content of Ba(MA)_2 in poly...Crosslinked poly(methyl methacrylate) and polystyrene with barium dimethacrylate [Ba(MA)_2] as crosslinking agent have been synthesized. The relationship between X-ray absorbability and the content of Ba(MA)_2 in polymers was investigated. TGA and DSC results indicated that the crosslinked polymers containing barium dimethacrylate have a much better heat stability than pure PMMA or PS. The mechanical properties of the polymers containing barium are improved in comparison with the pure PMMA.展开更多
A new copolymer was synthesized by free radical polymerization in solution from methyl 3α-methylacryloyl-7α, 12α-dihydroxy-5β-cholan-24-oate (MACAME) and maleic anhydride (MAN). The copolymer was characterized by ...A new copolymer was synthesized by free radical polymerization in solution from methyl 3α-methylacryloyl-7α, 12α-dihydroxy-5β-cholan-24-oate (MACAME) and maleic anhydride (MAN). The copolymer was characterized by FT-IR and functional group analysis. The reactivity ratios of the two monomers were estimated [r_1 = 11.6 (MACAME), r_2 = 0.01(MAN)] by conducting a series of copolymerizations with a variety of monomer feed compositions and analyzing thecopolymer composition. Thermogravimetric and differential scanning calorimetric analyses of the samples indicate that thecopolymer possesses good thermal stability. The temperature at which the copolymer samples experienced a 10% weight loss(T_(WL)) is over 287℃, and the T_g ranged from 174 to 185℃ for the copolymers.展开更多
Plasma treatment is necessary to optimize the performance of biomaterial surfaces.It enhances and regulates the performance of biomaterial su rfaces,creating an effective interface with the human body.Plasma treatment...Plasma treatment is necessary to optimize the performance of biomaterial surfaces.It enhances and regulates the performance of biomaterial su rfaces,creating an effective interface with the human body.Plasma treatments have the ability to modify the chemical com position and physical structu re of a surface while leaving its properties unaffected.They possess the ability to modify material su rfaces,eliminate contaminants,conduct investigations on cancer therapy,and facilitate wound healing.The subject of study in question involves the integration of plasma science and technology with biology and medicine.Using a helium plasma jet source,applying up to 18 kV,with an average power of 10 W,polymer foils were treated for 60 s.Plasma treatment has the ability to alter the chemical composition and physical structure of a su rface while maintaining its quality.This investigation involved the application of helium plasma at atmospheric pressure to polyamide 6 and polyethylene terephthalate sheets.The inquiry involves monitoring and assessing the plasma source and polymer materials,as well as analyzing the impacts of plasma therapy.Calculating the mean power of the discharge aids in assessing the economic efficacy of the plasma source.Electric discharge in helium at atmospheric pressure has beneficial effects in technology,where it increases the surface free energy of polymer materials.In biomedicine,it is used to investigate cytotoxicity and cell survival,particularly in direct blood exposure situations that can expedite coagulation.Comprehending the specific parameters that influence the plasma source in the desired manner for the intended application is of utmost im portance.展开更多
A pyridine-based diacid was synthesized via nucleophilic substitution reaction of 4-hydroxy benzoic acid with 2,6- dichloropyridine in the presence of potassium carbonate. The diacid was characterized using FT-IR and ...A pyridine-based diacid was synthesized via nucleophilic substitution reaction of 4-hydroxy benzoic acid with 2,6- dichloropyridine in the presence of potassium carbonate. The diacid was characterized using FT-IR and 1H-NMR spectroscopic methods and also with elemental analysis. Polycondensation reaction of the diacid with different diols including 1,4-dihydroxy benzene, 1,5-dihydroxy naphthalene, bis-phenol A and bis-phenol-P resulted in preparation of pyridine-based poly（ether-ester）s. The polymers were characterized and their physical and thermal properties including inherent viscosity, molecular weight, solubility, thermal stability, thermal behavior and crystallinity were studied. They revealed high heat-resistance and improved solubility in polar solvents. Structure-property relations for the prepared polyester were also studied.展开更多
In this paper,we present a novel approach to enhancing the visible light photodetection efficiency of reduced graphene oxide(rGO)by incorporating polypyrrole(Ppy)nanoparticles sized between 126 nm and 1025 nm.The rGO ...In this paper,we present a novel approach to enhancing the visible light photodetection efficiency of reduced graphene oxide(rGO)by incorporating polypyrrole(Ppy)nanoparticles sized between 126 nm and 1025 nm.The rGO and Ppy nanoparticles were synthesized via Hummer’s method and chemical polymerization,respectively.Characterization was performed using scanning electron microscope(SEM),transmission electron microscope(TEM),Raman spectroscopy,and optical measurements.The rGO/Ppy photodetector demonstrated a high photoresponsivity of 15 mA/W and a broad spectral response from 405 nm to 805 nm,indicating improved efficiency and versatility.This study high-lights the potential of tailored Ppy nanoparticle sizes in advancing rGO photodetectors for high-performance optoelectronic applications.展开更多
DOSY(diffusion ordered spectroscopy)NMR is a technique that separates NMR signals of different species according to their diffusion coefficients.It is a powerful technique to provide solid characterization evidence fo...DOSY(diffusion ordered spectroscopy)NMR is a technique that separates NMR signals of different species according to their diffusion coefficients.It is a powerful technique to provide solid characterization evidence for various applications in the chemical industry.Encapsulation and functional polymer grafting are two important capabilities in the chemical industry for new product development with challenging characterization requirements.Model systems of encapsulation and grafted polymer were studied and the characterization methods were set up by DOSY NMR.展开更多
The main objective was to study the anticorrosion performance of poly（o-toluidine）/nano ZrO2/epoxy composite coating.Poly（o-toluidine）/nano ZrO2 composite was prepared by in situ polymerization of o-toluidine mono...The main objective was to study the anticorrosion performance of poly（o-toluidine）/nano ZrO2/epoxy composite coating.Poly（o-toluidine）/nano ZrO2 composite was prepared by in situ polymerization of o-toluidine monomer in the presence of nano ZrO2 particles.Fourier transformation infrared spectroscopy（FT-IR）,UV-visible spectroscopy（UV-vis）,X-ray diffraction（XRD）,Scanning electron microscopy（SEM）,and Thermogravimetric analysis（TGA） were used to characterize the composition and structure of the composite.Poly（o-toluidine）/nano ZrO2 composite was mixed with epoxy resin through a solution blending method and the three components poly（o-toluidine）/nano ZrO2/epoxy composite coating was coated onto the surface of steel sample by the brush coating method.The anticorrosion performance of poly（o-toluidine）/nano ZrO2/epoxy composite coating on steel sample was studied by polarization curve and electrochemical impendence spectroscopy in 3.5% Na Cl solution as corrosion environment and also compared with that of poly（o-toluidine）/epoxy composite coating and pure epoxy coating.It was observed that the composite coating containing poly（otoluidine）/nano ZrO2 composite has got higher corrosion protection ability than that of poly（o-toluidine）.The electrochemical measurement results demonstrated that poly（o-toluidine） fillers improve the electrochemical anticorrosion performance of epoxy coating and the addition of nano ZrO2 particles increases the tortuosity of the diffusion pathway of corrosive substances.展开更多
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）.
文摘Crosslinked poly(methyl methacrylate) and polystyrene with barium dimethacrylate [Ba(MA)_2] as crosslinking agent have been synthesized. The relationship between X-ray absorbability and the content of Ba(MA)_2 in polymers was investigated. TGA and DSC results indicated that the crosslinked polymers containing barium dimethacrylate have a much better heat stability than pure PMMA or PS. The mechanical properties of the polymers containing barium are improved in comparison with the pure PMMA.
基金NSERC of Canada and Nankai University for financial support. H. Li thanks the National Natural Science Foundation of China for a travel award in support of the collaborative research program (No. 20074016).
文摘A new copolymer was synthesized by free radical polymerization in solution from methyl 3α-methylacryloyl-7α, 12α-dihydroxy-5β-cholan-24-oate (MACAME) and maleic anhydride (MAN). The copolymer was characterized by FT-IR and functional group analysis. The reactivity ratios of the two monomers were estimated [r_1 = 11.6 (MACAME), r_2 = 0.01(MAN)] by conducting a series of copolymerizations with a variety of monomer feed compositions and analyzing thecopolymer composition. Thermogravimetric and differential scanning calorimetric analyses of the samples indicate that thecopolymer possesses good thermal stability. The temperature at which the copolymer samples experienced a 10% weight loss(T_(WL)) is over 287℃, and the T_g ranged from 174 to 185℃ for the copolymers.
基金financially supported by UEFISCDI,PNCDI III,project PN-III-P1-1.1-TE-2021(No.150/09.06.2022)supported by COST(European Cooperation in Science and Technology,available online:https://www.cost.eu,accessed on 20 November 2023)。
文摘Plasma treatment is necessary to optimize the performance of biomaterial surfaces.It enhances and regulates the performance of biomaterial su rfaces,creating an effective interface with the human body.Plasma treatments have the ability to modify the chemical com position and physical structu re of a surface while leaving its properties unaffected.They possess the ability to modify material su rfaces,eliminate contaminants,conduct investigations on cancer therapy,and facilitate wound healing.The subject of study in question involves the integration of plasma science and technology with biology and medicine.Using a helium plasma jet source,applying up to 18 kV,with an average power of 10 W,polymer foils were treated for 60 s.Plasma treatment has the ability to alter the chemical composition and physical structure of a su rface while maintaining its quality.This investigation involved the application of helium plasma at atmospheric pressure to polyamide 6 and polyethylene terephthalate sheets.The inquiry involves monitoring and assessing the plasma source and polymer materials,as well as analyzing the impacts of plasma therapy.Calculating the mean power of the discharge aids in assessing the economic efficacy of the plasma source.Electric discharge in helium at atmospheric pressure has beneficial effects in technology,where it increases the surface free energy of polymer materials.In biomedicine,it is used to investigate cytotoxicity and cell survival,particularly in direct blood exposure situations that can expedite coagulation.Comprehending the specific parameters that influence the plasma source in the desired manner for the intended application is of utmost im portance.
文摘A pyridine-based diacid was synthesized via nucleophilic substitution reaction of 4-hydroxy benzoic acid with 2,6- dichloropyridine in the presence of potassium carbonate. The diacid was characterized using FT-IR and 1H-NMR spectroscopic methods and also with elemental analysis. Polycondensation reaction of the diacid with different diols including 1,4-dihydroxy benzene, 1,5-dihydroxy naphthalene, bis-phenol A and bis-phenol-P resulted in preparation of pyridine-based poly（ether-ester）s. The polymers were characterized and their physical and thermal properties including inherent viscosity, molecular weight, solubility, thermal stability, thermal behavior and crystallinity were studied. They revealed high heat-resistance and improved solubility in polar solvents. Structure-property relations for the prepared polyester were also studied.
文摘In this paper,we present a novel approach to enhancing the visible light photodetection efficiency of reduced graphene oxide(rGO)by incorporating polypyrrole(Ppy)nanoparticles sized between 126 nm and 1025 nm.The rGO and Ppy nanoparticles were synthesized via Hummer’s method and chemical polymerization,respectively.Characterization was performed using scanning electron microscope(SEM),transmission electron microscope(TEM),Raman spectroscopy,and optical measurements.The rGO/Ppy photodetector demonstrated a high photoresponsivity of 15 mA/W and a broad spectral response from 405 nm to 805 nm,indicating improved efficiency and versatility.This study high-lights the potential of tailored Ppy nanoparticle sizes in advancing rGO photodetectors for high-performance optoelectronic applications.
文摘DOSY(diffusion ordered spectroscopy)NMR is a technique that separates NMR signals of different species according to their diffusion coefficients.It is a powerful technique to provide solid characterization evidence for various applications in the chemical industry.Encapsulation and functional polymer grafting are two important capabilities in the chemical industry for new product development with challenging characterization requirements.Model systems of encapsulation and grafted polymer were studied and the characterization methods were set up by DOSY NMR.
基金Funded by the Innovation Project of Guangxi Graduate Education(No.YCSZ2014202)
文摘The main objective was to study the anticorrosion performance of poly（o-toluidine）/nano ZrO2/epoxy composite coating.Poly（o-toluidine）/nano ZrO2 composite was prepared by in situ polymerization of o-toluidine monomer in the presence of nano ZrO2 particles.Fourier transformation infrared spectroscopy（FT-IR）,UV-visible spectroscopy（UV-vis）,X-ray diffraction（XRD）,Scanning electron microscopy（SEM）,and Thermogravimetric analysis（TGA） were used to characterize the composition and structure of the composite.Poly（o-toluidine）/nano ZrO2 composite was mixed with epoxy resin through a solution blending method and the three components poly（o-toluidine）/nano ZrO2/epoxy composite coating was coated onto the surface of steel sample by the brush coating method.The anticorrosion performance of poly（o-toluidine）/nano ZrO2/epoxy composite coating on steel sample was studied by polarization curve and electrochemical impendence spectroscopy in 3.5% Na Cl solution as corrosion environment and also compared with that of poly（o-toluidine）/epoxy composite coating and pure epoxy coating.It was observed that the composite coating containing poly（otoluidine）/nano ZrO2 composite has got higher corrosion protection ability than that of poly（o-toluidine）.The electrochemical measurement results demonstrated that poly（o-toluidine） fillers improve the electrochemical anticorrosion performance of epoxy coating and the addition of nano ZrO2 particles increases the tortuosity of the diffusion pathway of corrosive substances.
