A series of polyacrylate emulsions were blended with tackifier resin emulsions such as modified rosin emulsion, C5 resin and C9 resin emulsion. The miscibility of the polyacrylates and tackifier resins was investigate...A series of polyacrylate emulsions were blended with tackifier resin emulsions such as modified rosin emulsion, C5 resin and C9 resin emulsion. The miscibility of the polyacrylates and tackifier resins was investigated by means of SEM and visual observation. The phase diagrams of the miscibility change systematically with the polarity of polyacrylates and tackifier resins. The influence of the content of the tackifier resins on the adhesion properties of the; polyacrylate emulsions were also studied. The results show that the 180 degrees C peel strength is improved as the amount of the tackifier resin increases and comes to a maximum at a specific content. The ball tack property decreases slightly and the hold strength changes complicatedly as the tackifier resin increases.展开更多
The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechani...The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechanical method. Single glass transition temperatures intermediate between the two pure components were observed for all blend levels. The secondary relaxation mechanism should relate to not only diester linkage, but also hydroxyether structural unit in the system. Fourier transform infrared spectroscopy (FTIR) is applied to study the curing reaction and intermolecular specific interaction of the system. The results indicate the PEO participates the crosslinking reaction, accelerates the curing reaction and make the reaction more perfect. The shifts of the hydroxyl band and carbonyl band demonstrate the presence of the intermolecular interaction in the cured blend. Moreover, the molecular interaction between the side hydroxyl in the hydroxyether units and the ether bond in PEO macromolecules is stronger.展开更多
By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found...By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found that the sonic velocity of the blends decreased as thetemperature increased, but attenuation coefficient increased and possessed a peak value. Largervelocity and smaller attenuation coefficient(α)can be obtained from perfect crosslinking networkstructures of pure DGEBA cured with phthalic anhydride(PA). As for cured DGEBA/PEO blendsystems,sonic velocity decreased as a function of PEO concentration,but attenuation coefficient(α) increased.展开更多
The thermal and dimensional stability of epoxy resin(EP)in-situ modified by cyanate ester(CE)and polydimethylsiloxane(PDMS)are investigated by means of experiments and numerical simulation.Thermal gravimetric analysis...The thermal and dimensional stability of epoxy resin(EP)in-situ modified by cyanate ester(CE)and polydimethylsiloxane(PDMS)are investigated by means of experiments and numerical simulation.Thermal gravimetric analysis(TGA)and differential scanning calorimeter(DSC)are used to analyze the heat resistance of the modified EP.The dimensional stability is characterized by the volume shrinkage of the series PDMS/CE/EP obtained by the density method.The chemical structure of the PDMS/CE/EP is analyzed by Fourier transform infrared spectroscopy(FTIR).The results of TGA and DSC indicate that the thermal stability of PDMS/CE/EP decreases firstly and then increases with the increase in the amount of CE.The addition of PDMS shows a slight effect on the thermal stability.The 40%CE makes the blending system exhibit the lowest initial decomposition temperature,which reduces by 15.5%and 40.8%compared with pure EP and CE,respectively.The FTIR results suggested that the influence of CE on the thermal stability of the modified EP is mainly ascribed to the generation of oxazolidinone ring with low thermal stability and the increase in the triazine ring with high thermal stability.The volume shrinkage measurement results show that the introduction of CE and PDMS are both beneficial to the improvement of the dimensional stability of the blending systems.The in-situ addition of 80%CE shows the lowest volume shrinkage of6.11%.The thermal stress distribution of PDMS/CE/EP generated during the solidification process is simulated by the finite element analysis.The results suggested that the introduction of 80%CE into EP results in the lowest thermal stress in the blending system,which indicates that the system has the lowest volume shrinkage,which agrees well with the experimental results.展开更多
文摘A series of polyacrylate emulsions were blended with tackifier resin emulsions such as modified rosin emulsion, C5 resin and C9 resin emulsion. The miscibility of the polyacrylates and tackifier resins was investigated by means of SEM and visual observation. The phase diagrams of the miscibility change systematically with the polarity of polyacrylates and tackifier resins. The influence of the content of the tackifier resins on the adhesion properties of the; polyacrylate emulsions were also studied. The results show that the 180 degrees C peel strength is improved as the amount of the tackifier resin increases and comes to a maximum at a specific content. The ball tack property decreases slightly and the hold strength changes complicatedly as the tackifier resin increases.
基金This study is partially supported by the National Natural Science Foundation of China.
文摘The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechanical method. Single glass transition temperatures intermediate between the two pure components were observed for all blend levels. The secondary relaxation mechanism should relate to not only diester linkage, but also hydroxyether structural unit in the system. Fourier transform infrared spectroscopy (FTIR) is applied to study the curing reaction and intermolecular specific interaction of the system. The results indicate the PEO participates the crosslinking reaction, accelerates the curing reaction and make the reaction more perfect. The shifts of the hydroxyl band and carbonyl band demonstrate the presence of the intermolecular interaction in the cured blend. Moreover, the molecular interaction between the side hydroxyl in the hydroxyether units and the ether bond in PEO macromolecules is stronger.
文摘By means of ultrasonic attenuation apparatus, the ultrasonic velocity and attenuation ofanhydride-cured epoxy resins (EP)/poly (ethylene oxide) (PEO) blends were measured on thebasis of pulse-echo method. It was found that the sonic velocity of the blends decreased as thetemperature increased, but attenuation coefficient increased and possessed a peak value. Largervelocity and smaller attenuation coefficient(α)can be obtained from perfect crosslinking networkstructures of pure DGEBA cured with phthalic anhydride(PA). As for cured DGEBA/PEO blendsystems,sonic velocity decreased as a function of PEO concentration,but attenuation coefficient(α) increased.
基金the Shanghai Aerospace Science and Technology Innovation Fund of China(No.SAST2019-122)。
文摘The thermal and dimensional stability of epoxy resin(EP)in-situ modified by cyanate ester(CE)and polydimethylsiloxane(PDMS)are investigated by means of experiments and numerical simulation.Thermal gravimetric analysis(TGA)and differential scanning calorimeter(DSC)are used to analyze the heat resistance of the modified EP.The dimensional stability is characterized by the volume shrinkage of the series PDMS/CE/EP obtained by the density method.The chemical structure of the PDMS/CE/EP is analyzed by Fourier transform infrared spectroscopy(FTIR).The results of TGA and DSC indicate that the thermal stability of PDMS/CE/EP decreases firstly and then increases with the increase in the amount of CE.The addition of PDMS shows a slight effect on the thermal stability.The 40%CE makes the blending system exhibit the lowest initial decomposition temperature,which reduces by 15.5%and 40.8%compared with pure EP and CE,respectively.The FTIR results suggested that the influence of CE on the thermal stability of the modified EP is mainly ascribed to the generation of oxazolidinone ring with low thermal stability and the increase in the triazine ring with high thermal stability.The volume shrinkage measurement results show that the introduction of CE and PDMS are both beneficial to the improvement of the dimensional stability of the blending systems.The in-situ addition of 80%CE shows the lowest volume shrinkage of6.11%.The thermal stress distribution of PDMS/CE/EP generated during the solidification process is simulated by the finite element analysis.The results suggested that the introduction of 80%CE into EP results in the lowest thermal stress in the blending system,which indicates that the system has the lowest volume shrinkage,which agrees well with the experimental results.
