Studies On Aqueous Ambient Self-crosslinkable Polyacrylate Emulsion And Blending With Nano-silica Sol

An aqueous ambient crosslinkable polymer acrylic emulsion was abtained by adding adipic acid dihydrazide(ADH) to the polyacrylate emulsion incorporating diacetone acrylamide(DAAM), and this emulsion was synthesized by seeded-emulsion polymerization.As a consequence, a kind of white fluid polyacrylate emulsion was obtained. Then, blending nano-silica sol with this aqueous ambient self-crosslinkable polyacrylate emulsion in different ration.The emulsions and its latex films were characterized with rheologica measurements, Laser Light Scattering, Fourier transform infrated (FTIR), Scanning electron microscopy(SEM), Differential Scanning Calorimetry(DSC) and so on.The viscosities of the emulsion were measured with a NXS-ⅡA rotational viscometer. The results showed that the aqeous ambient self-crosslinkable polyacrylate emulsion and the emulsions blending with nano-silica sol are pseudoplastic fluid. The apparent viscosity (ηa), consistency factor(K), zero shear viscosity(η0) increased with increasing the silica sol content, but the emulsion flow index(n) is decreased. The apparent viscosity, consistency coefficient, zero shear viscosity of the emulsion after being laid two days increased but the flow index is decreased compared with the emulsion with the same silica sol content without laying.Fourier-transform infrared (FTIR) spectrometer was used for examining the room-temperature curing process of the crosslinkinkable acrylate resin, and for verifying reaction of carbonyl groups and hyrazide groups, also the presence of nano-silica sol. In this paper the tests for the latex it was shown that the hardness, impact strength, thermo-tacky temperature, water resistance and degree of cross-linking of the film rose with the copolymerization of DAAM, and blending emulsion increased with the nano-silica sol content.The aqueous ambient self-crosslinkable polyacrylate emulsion obtained by ADH to the polyacrylate emulsion incorporating DAAM, and blending with nano-silica sol passed the stability of calcium ion and gelation-thaw.SEM was employed to characterize the forms of the films. And the results indicated that the nano-silica sol could change the form of latex film with the content increasing the change increasing.The particle size and particle size distribution (PSD) of the emulsions were measured using a laser scattering. The results showed the presence of nano-silica sol did not change the particle sizes and PSD of aqueous ambient self-crosslinkable polyacrylate emulsion.DSC test method was used for investigation of the glass transition temperature (Tg) of the latex films. The results showed that the aqueous ambient self-crosslinkable polyacrylate emulsion was enhanced considerably the glass transition temperature of traditional polyacrylate emulsion. And the glass transition temperature of the emulsions enhanced more by bleding nano-silica sol with ambient self-crosslinkable polyacrylate emulsion.Therefore, the aqueous ambient crosslinkable polyacrylate emulsion containing DAAM with carbonyl groups and ADH with hydrazide groups have not only friendly environment property, minimization of the energy, but also good performance property than traditional polyacrylate emulsion. These properties were modified further by blending nano-silicasol with aqueous ambient crosslinkable polyacrylate emulsion.