| Recently, much more attentions were paid by a number of researchers on nanoscience and nanotechnology. In the present sense, nanoscience can be taken to refer to the study of the properties of materials that differ from those of bulk matter owing to their minisize effect, surface effect, quantum effect, etc. In this manner, one might hope to produce artificial new materials that have interesting novel properties and characteristics that are of interest from the point of view of both fundamental science and of technology.There is a growing interesting in organic-inorganic nanocomposites due to their obvious potential applications ranging from colloid stabilizers, electro-optical devices and nanocomposite materials since we can design such novel materials so that they can compensate each other for unfavourable properties of the other component. Recently, many documents have reported assembly of attaching polymer chain into nanoparticles surface, including physicochemical or chemical processes. Of these works, emulsion polymerization is the technique most frequently used for encapsulation reaction of minerals with polymers by far. Usually the encapsulation reactions via emulsion polymerization are based on the fact that inorganic surface are hydrophilic, while polymers are hydrophobic. To facilitate polymerization on the inorganic surface, modification of the inorganic surface can be carried out by using the molecules reactions of silane, titanate, silazanes and siloxanes with minerals. Polyacrylate (PA) latexes are important classes of materials in paint and ink industries due to a number of applications such as coating, adhesives. However, these latexes are inferior to the properties of water resistance and anti-fouling. In order to improve the properties of PA latexes, silica nanoparticles/PA hybrid latexes were synthesized. In this paper, the methods of in-situ polymerization and seed growing emulsion polymerization, along with the influence of different synthetic routes, reaction conditions and surface modification of silica nanoparticles on properties of silica nanoparticles/PA hybrid latexes, were introduced and discussed in detail. Also silicananoparticles/PA hybrid latexes were characterized by modern analytic tools of TEM, DMA, FT-1R imaging and XRD, etc. The main conclusions are drawn as follows:1. It has been noted that the morphology of hybrid latexes depended on the ways of emulsion polymerization. The results of TEM measurements show that core-shell structure dominates in silica nanoparticles/PA hybrid latexes prepared by the method of seed growing, while petaline structure dominates in the hybrid latexes prepared by the method of in-situ polymerization.2. The dispersion of silica nanoparticles in hybrid latexes is an important issue during polymerization. The result is shown that the silica nanoparticles could be dispersed well in PA hybrid latexes under functionalizing silica nanoparticles with the modified agent. The given FT-IR results are further reinforced to prove this viewpoint.3. The results of mechanical properties of silica nanoparticles/PA hybrid latexes further suggest that the content of silica nanopaticles has influenced on the properties of hybrid latexes and there is a maximum value in mechanical properties with the increase of the content of modified silica nanoparticles. Also the mechanical properties of hybrid latexes with modified silica nanoparticles are better than those of hybrid latexes without modified silica nanoparticles.4. The effects of the content of modified silica on contact angles and particle size & distribution of hybrid latexes have been investigated. The contact angles of hybrid latexes have a maximum value with the increase of the content of modified silica nanoparticles.5. The influence of modified silica nanoparticles content on the particle size of PA hybrid latex was very observed by DLS measurements, that is, variation of particle size of hybrid latexes is too little with adding a small amount of silica nanoparticles. Howev...
|
PDF Full Text Request