Poly(urea-formaldehyde)(PUF)microcapsules were prepared by in-situ polymerization with four different pro-cesses in this paper.The chemical composition,surface morphology,particle size distribution,and thermal sta-bil...Poly(urea-formaldehyde)(PUF)microcapsules were prepared by in-situ polymerization with four different pro-cesses in this paper.The chemical composition,surface morphology,particle size distribution,and thermal sta-bility were characterized by FTIR,SEM,particle size analyzer,and TGA,respectively.The results demonstrated that the agglomeration of the PUF microcapsules was related to the agglomeration of the emulsion particles caused by the changes of emulsion interface during the shell polymerization.Due to the slow deposition of the shell material,the PUF microcapsules with the core-shell structure prepared by the process with ammonium chloride as the last additive showed good dispersibility with an average diameter of 6.36μm,high core content of 71.3 wt%,and high yield of 61.3 wt%.The PUF microcapsules had good thermal stability below 216?C.The PUF microcapsules could be uniformly dispersed in the epoxy coating in a single form.The epoxy coating with 2 wt%PUF microcapsules showed good self-healing property,and the service life of the coating was about doubled.展开更多
SiO_(2)-based microcapsules containing hydrophobic molecules exhib-ited potential applications such as extrinsic self-healing,drug delivery,due to outstanding thermal and chemical stability of SiO_(2).However,to const...SiO_(2)-based microcapsules containing hydrophobic molecules exhib-ited potential applications such as extrinsic self-healing,drug delivery,due to outstanding thermal and chemical stability of SiO_(2).However,to construct SiO_(2)-based microcapsules with both high encapsulation loading and long-term structural stability is still a troublesome issue,limiting their further utilization.We herein design asingle-batch route,a combined interfacial and in-situ polymerization strategy,to fabricate epoxy-containing SiO_(2)-based microcapsules with both high encapsu-lation loading and long-term structural stability.The final SiO_(2)-based microcapsules preserve high encapsulation loading of 85.7 wt% by controlling exclusively hydrolysis and condensed polymerization at oil/water interface in the initial interfacial polymerization step.In the subsequent in-situ polymerization step,the initial SiO_(2)-based microcapsules as seeds could efficiently harvest SiO_(2) precursors and primary SiO 2 particles to finely tune the SiO_(2) wall thickness,thereby enhancing long-term structural stability of the final SiO_(2)-based microcapsules including high thermal stability with almost no any weight loss until 250℃,and strong tolerance against nonpolar solvents such as CCl_(4) with almost unchanged core-shell structure and unchanged core weight after immersing into strong solvents for up to 5 days.These SiO_(2)-based microcapsules are extremely suited for processing them into anticorrosive coating in the presence of nonpolar solvents for self-healing application.展开更多
基金This work was supported by the Jiangsu National Synergetic Innovation Center for Advanced Materials and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Poly(urea-formaldehyde)(PUF)microcapsules were prepared by in-situ polymerization with four different pro-cesses in this paper.The chemical composition,surface morphology,particle size distribution,and thermal sta-bility were characterized by FTIR,SEM,particle size analyzer,and TGA,respectively.The results demonstrated that the agglomeration of the PUF microcapsules was related to the agglomeration of the emulsion particles caused by the changes of emulsion interface during the shell polymerization.Due to the slow deposition of the shell material,the PUF microcapsules with the core-shell structure prepared by the process with ammonium chloride as the last additive showed good dispersibility with an average diameter of 6.36μm,high core content of 71.3 wt%,and high yield of 61.3 wt%.The PUF microcapsules had good thermal stability below 216?C.The PUF microcapsules could be uniformly dispersed in the epoxy coating in a single form.The epoxy coating with 2 wt%PUF microcapsules showed good self-healing property,and the service life of the coating was about doubled.
文摘SiO_(2)-based microcapsules containing hydrophobic molecules exhib-ited potential applications such as extrinsic self-healing,drug delivery,due to outstanding thermal and chemical stability of SiO_(2).However,to construct SiO_(2)-based microcapsules with both high encapsulation loading and long-term structural stability is still a troublesome issue,limiting their further utilization.We herein design asingle-batch route,a combined interfacial and in-situ polymerization strategy,to fabricate epoxy-containing SiO_(2)-based microcapsules with both high encapsu-lation loading and long-term structural stability.The final SiO_(2)-based microcapsules preserve high encapsulation loading of 85.7 wt% by controlling exclusively hydrolysis and condensed polymerization at oil/water interface in the initial interfacial polymerization step.In the subsequent in-situ polymerization step,the initial SiO_(2)-based microcapsules as seeds could efficiently harvest SiO_(2) precursors and primary SiO 2 particles to finely tune the SiO_(2) wall thickness,thereby enhancing long-term structural stability of the final SiO_(2)-based microcapsules including high thermal stability with almost no any weight loss until 250℃,and strong tolerance against nonpolar solvents such as CCl_(4) with almost unchanged core-shell structure and unchanged core weight after immersing into strong solvents for up to 5 days.These SiO_(2)-based microcapsules are extremely suited for processing them into anticorrosive coating in the presence of nonpolar solvents for self-healing application.
