Copolymers, graft emulsifying properties

We have shown (12, 14) that block and graft copolymers (BG copolymers have emulsifying properties in polymeric oil-in-oil emulsions. ... 

It can be concluded that the best emulsifying properties are obtained with two-block copolymers, and that these are superior to three-block copolymers and to graft copolymers. Furthermore, a two-block copolymer is most efficient if its composition is about 50 50 and if its molecular weight is higher than those of the corresponding homopolymers. These results agree with those obtained recently by Skoulios and co-workers (II). An explanation of these phenomena by Meier is based on the different precipitation rates of the various polymers during solvent evaporation (12). 

VE1 Veibragghe, S., Bemaerts, K., and DuPrez, F.E., Thermo-responsive and emulsifying properties of poly(A/-viitylcaprolactam) based graft copolymers, Macromol. Chem. Phys., 204, 1217, 2003. 

The emulsifying property of the graft copolymer was examined using a DDS-llA Conductometer. In the procedure, the changes of conductivity, for an emulsion formed by dropping water slowly into a stirred toluene solution of the graft copolymer, are followed. 

Branched polymers have attracted increasing interest due to their numerous and various applications originating from a large variety of available polymer topologies, compositions, or morphologies for phase separating systems, as emulsifier and interfacial compatibilizers, or for surface modification properties. Graft copolymers are one of the important... 

Developing well defined blends of truly Incompatible polymers requites the use of compatlblllzatlon technology, which has been pioneered in the laboratories of Professors Paul (8), Rless (9), Teyssle (10), and Helkens (11), who have demonstrated and Illustrated how block and graft copolymers when judiciously selected can act as polymeric emulsifiers stabilizing the dispersion of truly Incompatible polymers (fig.3). Enhanced properties are then obtained through morphology control. 

Grafting of hydroxypropyl methylcellulose (HPMC) with acrylic acid to yield biodegradable and biocompatible copolymers-like hydrogel with improved properties was performed [34] to enhance drug activity and to reduce the frequency of the doses. The product was prepared by in situ emulsifier free emulsion polymerization through one-stage grafting. So, acrylic acid could intercalate into layers of HPMC... 

Block and graft copolymers may be absorbed at various surfaces liquid/gas, liquid/liquid, solid/liquid, etc. The surface-active properties of copolymers (particularly block polymers) have made them useful as dispersants, emulsifiers, foam stabilizers, flocculants and wetting agents. These aspects of block copolymers do not fall within the scope of this review. An overview of these applications has been presented by Reiss, who has also widely researched the area. ... 

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