| The environmental-friendly waterborne emulsion has the features of low-carbon,environmental protection and practical application value, which can significantly reduce theemission of VOC. In this paper, acrylic emulsions were modified by organic silicone andinorganic nanoparticles respectively, and the stability of the emulsion and the performanceof its film were also studied, in order to obtain environmental-friendly waterborne coatingswith high performance.Firstly, octamethyl cyclotetrasiloxane was selected as organic silicon monomer tomodify acrylic emulsion. The monomer ratio, adding process, temperature, dosage ofinitiator, ratio of different type of emulsifiers and so on were studied to obtain stableemulsion with small and uniform particle size, small gel rate and high conversion rate of95.2%, which showed excellent Ca2+, centrifugal and mechanical stability as well.Secondly, the modification process of silica sol was studied in the paper. The optimumcondition of the modification process was as follows: silane coupling agent B contentsaccounted15%of SiO2, pH around89, the ratio of ethanol and SiO2at1:1and the silicasol modified at60℃for24hours. The stable modified silica sol was obtained with particlesize at51.40nm and electric potential at-52.81mV. The organic-inorganic hybrid emulsionwas synthesized as follows: the ratio of emulsifier OP-10and DNS-86was1:3, and themodified silica sol and small amount of emulsifier were added in the reactor first, and thenthe hydrophilic functional monomer was added later to couple with silica sol. We obtainedthe stable organic-inorganic hybrid emulsion with high silicon content of20%, high solidcontend of40%and average particle size of121nm, which had excellent heat resistance.The result of TEM analysis showed that large amount of SiO2particles combined with thelatex particles, similar to the structure of―pomegranate‖.Finally, we focused on the mechanical properties, water resistance, alkali resistance,contact angle of different silicone-acrylic latex films. The results indicated that thesilicone-acrylic hybrid latex film mentioned above showed higher hardness and betterflexibility, while it was inferior to organic silicone-acrylic latex and that of commercially available in the aspect of water resistance and contact angle, which need furtherimprovement in future research. The silicone-acrylic hybrid latex film mentioned aboveshowed good alkali resistance, as the glossiness didn’t drop much while compared toorganic silicone-acrylic latex. |
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