New ethyl cellulose/acrylic hybrid latexes and coatings via miniemulsion polymerization

Abstract

Ethyl cellulose (EC) was incorporated into copolymer latexes via miniemulsion polymerization. The effects of EC viscosity and EC content on droplet size, particle size and polymerization kinetics were investigated. The higher the EC content and viscosity, the larger the droplet size and the less stable the latex suspension. Small droplets that could be efficiently nucleated were formed for the lower-viscosity EC but the latex still showed limited colloidal stability. This was attributed to some phase-incompatibility between EC and the acrylic polymer. These stability issues were overcome by using an oil-soluble initiator and a cross-linker. The later enabled to physically entrap EC inside the polymer particles while the former allowed in situ grafting of the growing acrylic radicals to the EC backbone decreasing thereby the extent of phase separation. Thermal-mechanical analyses evidenced that the films obtained from the hybrid latexes displayed better properties than the EC-free latex films or the physical blends. This supports the hypothesis of formation of hybrid latexes that synergistically combine the properties of the acrylic matrix and the EC polymer. Interestingly, a significant increase of the elastic modulus was observed between 50-90°C. This mechanical reinforcement was tentatively attributed to the formation of a percolating EC-based hybrid phase.

Light Energy Collection in a Porphyrin–Imide–Corrole Ensemble

“…As a result, the part of the uPHA loaded droplets shrink in size which can ultimately result in the uPHA being expelled out of the droplets causing coagulation of PHA on the stirrer, as was observed to low extents for high uPHA content formulations initiated with KPS. This phenomenon was also recently observed by Chen et al24 for ethyl cellulose loaded methyl methacrylate miniemulsions. In the latter hybrid miniemulsion system, homogeneous nucleation resulted in the formation of a large coagulum, as the expelled ethyl cellulose was not stabilized by the available surfactant.…”

“…Furthermore, it can be observed that the droplet size increases as the loading of uPHA increases. The viscosity of the dispersed organic phase is an important parameter governing the miniemulsion droplet size 21–24. This relationship has been quantified by Mabille et al,25 where the miniemulsion droplet size scales with the viscosity ratio ( R ) between the dispersed and continuous phase.…”

Controlled-release urea encapsulated by ethyl cellulose/butyl acrylate/vinyl acetate hybrid latex

“…Thus, the tensile pr operties of EC/BA/VAc fi lms at room temperature were greater than that of BA/VAc fi lms (0% EC). The observed change in the mechanical properties agreed with the DSC measurements and the results described in the literature 22 . The addition o f EC may have weakened the hydrogen bonds and interactions between polar groups of the polymer.…”

“…A few copolymerizations are performed in water. For example, Chen et al 22 reported that ethyl cellulose (EC)/butyl acrylate (BA)/methyl methacrylate (MMA) hybrid latexes can be prepared by batch emulsion polymerization in water containing 6.6% toluene and 6.7% hexadecane by weight. In our previous study 23 , we have only prepared EC/BA/ VAc hybrid latex by pre-emulsifi ed semi-continuous seed emulsion polymerization in water without any organic solvent and evaluated the effects of the EC content on the monomer conversion, particle size, and viscosity of EC/BA/VAc emulsions.…”

Processing, Dynamic mechanical thermal analysis, and dielectric properties of barium titanate/cellulosic polymer nanocomposites

“…Figure shows the DMTA curves for EC and BT/EC nanocomposites. Thermal transition of EC from glassy state to rubbery state occurs at about 122–130°C . As shown in Fig.…”