Concentrated Emulsion Pathway To Self-Compatibilization Of Polymer Blends

Self-compatibilization is a novel method for preparing compatibilized polymer blends via concentrated emulsion polymerization. In this method, two partially polymerized concentrated emulsions are mechanically mixed, and then they are subjected to complete polymerization. Some compatibilizers are generated at the interfaces between the two kinds of cells, which compatibilize the homopolymers generated simultaneously inside the cells. In particular, when a rigid polymer was blended in this manner with a flexible one, tough materials were obtained. SELF-COMPATIBILIZATION VIA DIFFUSION OF CONCENTRATED EMULSIONSTwo concentrated emulsions of styrene (St) and butyl acrylate (BA) in water were prepared respectively. Each system contains a small amount of initiator in the dispersed phase. This kind of emulsion has a large volume fraction of the dispersed phase (as large as 0.99). After the two concentrated emulsions were partially polymerized, they were mixed mechanically and subjected to complete polymerization. Subsequently reactions between the interfaces of different cells occurred. During the latter diffusion polymerization, a kind of pseudo-block copolymer was generated which constituted the compatibilizers of the blend systems. Fourier transform infrared spectra (FTIR), Dynamic mechanical thermal analysis (DMTA), Rheometric testing, Scanning electron microscope (SEM) and Transmission electron microscope (TEM) were employed to characterize the compatibilization of the polymer blends. The results showed that the blend materials thus obtained possessed excellent compatibilization. SELF-COMPATIBILIZATION VIA BRIDGING BY MACROMONOMERIn this case, a macromonomer - Poly (ethylene glycol) dimethacrylate (PEGD) was employed as the precursor of a compatibilizer that can bridge the polystyreneand poly (butyl methacrylate). As in the preceding section, two concentrated emulsions in water were prepared first. In each of the concentrated emulsions, the continuous phase was a mixture containing SDS solution and PEGD (or introduced after mixing of the partially polymerized concentrated emulsion). The partial polymerization of the two concentrated emulsions was conducted and mixed mechanically after a 22.5% conversion was reached. Because of the vinyl groups at each of its ends, the PEGD copolymerized with styrene and butyl methacrylate in different cells, and thus some copolymers or networks containing both polystyrene and poly (butyl methacrylate) were formed. Such copolymers or networks constituted compatibilizers between polystyrene and poly (butyl methacrylate). The compatibility of the blends thus prepared was characterized by curves of dynamical mechanic mechanical thermal analysis (DMTA), Scanning electron microscope (SEM) and Transmission electron microscope (TEM). The impact properties and rheological curves of the blends showed excellent toughness and processability for base materials respectively. One can conclude that a macromonomer content of 0.025wt% to 0.050wt% provides the optimum benefit for the compatibilization of PS/PBMA blends.SELF-COMPATTOILIZATION VIA FUNCITONALLZED CONCENTRATED EMULSIONSTwo "functionalized" concentrated emulsions in water were prepared separately, one from a weakly polymerized mixture of styrene (St) and a small amount of acrylic acid (AA) and the other from a mixture of butyl methacrylate (or butyl acrylate) and a small amount of glycidyl methacrylate (GMA). After the two concentrated emulsions were polymerized partially, they were mixed and subjected to complete polymerization. During the latter polymerization, reactions between the carboxyl groups of the AA moieties of the St/AA copolymer and the glycidyl groups of the GMA-containing copolymer occurred, and copolymers and crosslinked structures were generated that constituted the compatibilizers of the system. The blend materials thus obtained possessed excellent toughness compared to those without functional groups.SELF-COMPATIBILIZATION VIA GRAFTING IN A CONCENTRATED EMULSIONA novel polymerization procedure, the concentra...