Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), ac...Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), acrylate (AA) and methyl acrylate (MAA) were used as reactive cosurfactants. With this process high polymer: surfactant weight ratios (40:1 or greater),relatively concentrated (~30wt. %) latexes and small (~60nm) particle diameters were obtained.Properties of the latexes were characterized by TEM, DSC, dynamic light scattering, and IR spectroscopy.展开更多
A novel zinc-rich pigment based on P(St-BA-MAA-SPAA) nano-latex was obtained, which is suitable for the use in hot alkali liquid medium. The nano-latex was synthesized by active emulsifier latex polymerization method ...A novel zinc-rich pigment based on P(St-BA-MAA-SPAA) nano-latex was obtained, which is suitable for the use in hot alkali liquid medium. The nano-latex was synthesized by active emulsifier latex polymerization method with monomers of styrene (St), butylacrylate (BA), methylacrylic acid(MAA) in the presence of active emulsifier 3-sulfopropylacrylate(SPAA). The synthesis condition and properties of the latex were investigated. And the anti-corrosive property of the resultant zinc-rich coating was studied. The results show that the nano-latex is self-stabilized and has a narrow particle diameter distribution, the average diameter of the latex particles is 71 nm. Zinc powders can be evenly dispersed in the nano-latex, which indicates that the P(St-BA-MAA-SPAA) nano latex can be used as the binder of zinc-rich coating. The resultant zinc-rich coating is able to resist the invasion of hot alkali solution(the temperature is 95 ℃ and the pH value is 14) for 480 h and the exposure time in salt spray is 1 200 h. Moreover, the coating shows good thermal conductivity and static electricity properties, its thermal conductivity and electric resistivity are 21-37 W/(m·K) and 6.7×105-3.5×106 Ω·cm, respectively.展开更多
Influences of polypropylene （PP） fiber and styrene-butadiene rubber （SBR） polymer latex on the strength performance, abrasion resistance of cement mortar were studied. The experimental results show that the flexur...Influences of polypropylene （PP） fiber and styrene-butadiene rubber （SBR） polymer latex on the strength performance, abrasion resistance of cement mortar were studied. The experimental results show that the flexural strength, brittleness index （σF/σC） and abrasion resistance can be improved significantly by the addition of PP fiber and SBR polymer latex. The relationship between the flexural strength and abrasion resistance was analyzed, showing a good linear relationship between them. The reinforced mechanism of PP fiber and SBR polymer latex on cement mortar was analyzed by some microscopic tests. The test results show that the addition of SBR polymer latex has no significant influence on the cement hydration after 7 d curing. Adding SBR polymer latex into cement mortar can form a polymer transition layer in the interfaces of PP fiber and cement hydrates, which improves the bonding properties between the PP fiber and cement mortar matrix effectively.展开更多
The present study assesses the hydration behavior of polymer modified and non-polymer containing calcium sulfoaluminate(CSA)cement pastes containing minor phase tri-calcium aluminate(C3A)when cured at ambient laborato...The present study assesses the hydration behavior of polymer modified and non-polymer containing calcium sulfoaluminate(CSA)cement pastes containing minor phase tri-calcium aluminate(C3A)when cured at ambient laboratory temperature with 50%relative humidity.The particular CSA cement is unique as it offers two potential paths for ettringite formation.In the presence of sufficient calcium sulfate,these two potential paths stem from either hydration of yeelimite or hydration of tri-calcium aluminate.The study assesses the microstructural behavior of cement pastes utilizing powdered x-ray diffraction(XRD)and thermogravimetric analysis(TGA/SDT).Additionally,the study utilizes direct tensile strength testing according to ASTM C307,Standard Test Method for Tensile Strength of Chemical Resistant Mortar,Grouts and Monolithic Surfacings to quantify relationships between microstructural characteristics and mechanical property performance for representative mortars.The present study is significant as it illustrates differences in microstructural behavior for CSA cement materials with and without polymer cured at constant 50%relative humidity.The present study suggests ettringite decomposition occurs within non-polymer containing CSA cement paste samples cured at constant low humidity.The present study presents polymer modification as an effective means for mitigating ettringite decomposition and subsequent strength loss in materials containing CSA cement cured at constant 50%relative humidity and 23℃.展开更多
基金CEM Foundation For N & T Joint Academy (Chinese Education Ministry Foundation for Nankai University and Tianjin University Joint Academy)
文摘Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), acrylate (AA) and methyl acrylate (MAA) were used as reactive cosurfactants. With this process high polymer: surfactant weight ratios (40:1 or greater),relatively concentrated (~30wt. %) latexes and small (~60nm) particle diameters were obtained.Properties of the latexes were characterized by TEM, DSC, dynamic light scattering, and IR spectroscopy.
文摘A novel zinc-rich pigment based on P(St-BA-MAA-SPAA) nano-latex was obtained, which is suitable for the use in hot alkali liquid medium. The nano-latex was synthesized by active emulsifier latex polymerization method with monomers of styrene (St), butylacrylate (BA), methylacrylic acid(MAA) in the presence of active emulsifier 3-sulfopropylacrylate(SPAA). The synthesis condition and properties of the latex were investigated. And the anti-corrosive property of the resultant zinc-rich coating was studied. The results show that the nano-latex is self-stabilized and has a narrow particle diameter distribution, the average diameter of the latex particles is 71 nm. Zinc powders can be evenly dispersed in the nano-latex, which indicates that the P(St-BA-MAA-SPAA) nano latex can be used as the binder of zinc-rich coating. The resultant zinc-rich coating is able to resist the invasion of hot alkali solution(the temperature is 95 ℃ and the pH value is 14) for 480 h and the exposure time in salt spray is 1 200 h. Moreover, the coating shows good thermal conductivity and static electricity properties, its thermal conductivity and electric resistivity are 21-37 W/(m·K) and 6.7×105-3.5×106 Ω·cm, respectively.
基金Funded by the Science Project from Department of Communication of Hubei Province
文摘Influences of polypropylene （PP） fiber and styrene-butadiene rubber （SBR） polymer latex on the strength performance, abrasion resistance of cement mortar were studied. The experimental results show that the flexural strength, brittleness index （σF/σC） and abrasion resistance can be improved significantly by the addition of PP fiber and SBR polymer latex. The relationship between the flexural strength and abrasion resistance was analyzed, showing a good linear relationship between them. The reinforced mechanism of PP fiber and SBR polymer latex on cement mortar was analyzed by some microscopic tests. The test results show that the addition of SBR polymer latex has no significant influence on the cement hydration after 7 d curing. Adding SBR polymer latex into cement mortar can form a polymer transition layer in the interfaces of PP fiber and cement hydrates, which improves the bonding properties between the PP fiber and cement mortar matrix effectively.
文摘The present study assesses the hydration behavior of polymer modified and non-polymer containing calcium sulfoaluminate(CSA)cement pastes containing minor phase tri-calcium aluminate(C3A)when cured at ambient laboratory temperature with 50%relative humidity.The particular CSA cement is unique as it offers two potential paths for ettringite formation.In the presence of sufficient calcium sulfate,these two potential paths stem from either hydration of yeelimite or hydration of tri-calcium aluminate.The study assesses the microstructural behavior of cement pastes utilizing powdered x-ray diffraction(XRD)and thermogravimetric analysis(TGA/SDT).Additionally,the study utilizes direct tensile strength testing according to ASTM C307,Standard Test Method for Tensile Strength of Chemical Resistant Mortar,Grouts and Monolithic Surfacings to quantify relationships between microstructural characteristics and mechanical property performance for representative mortars.The present study is significant as it illustrates differences in microstructural behavior for CSA cement materials with and without polymer cured at constant 50%relative humidity.The present study suggests ettringite decomposition occurs within non-polymer containing CSA cement paste samples cured at constant low humidity.The present study presents polymer modification as an effective means for mitigating ettringite decomposition and subsequent strength loss in materials containing CSA cement cured at constant 50%relative humidity and 23℃.
