This paper summarizes a study on emulsifier-free ultrasonically assisted in situ dynamic interfacial emulsion copolymerization process of acrylamide and styrene. The resulting emulsions are stable and uniform for several months. Thermogravimetric analysis (TGA) curves and reaction conversion measurements have provided an important knowledge regarding the emulsifier-free polymerization method. Solvent extractions (water, methanol, and xylene) have shown that the polymerization product is essentially a styrene-acrylamide copolymer. The copolymer produced is a block copolymer, PS-b-PAM, where each block contains small amounts of the other comonomer. The produced emulsions are film forming at room temperature in spite of the very high block T g s, owing to a unique water plasticization effect of the polyacrylamide blocks. Some films prepared from the PS-b-PAM have resulted in clear and transparent films. The presented interfacial dynamic polymerization process is fast, reaching 81% conversion within 2 hr of sonication at 4 C (low temperature owing to molecular weight and kinetic considerations), and produces very stable PS-b-PAM emulsions. TGA was extensively used as an analytical tool for determination of the reaction parameters and composition of the acrylamide-styrene copolymers.

SynopsisPoly(ether urethane)s as biomaterials display certain favorable mechanical and biocompatibility properties. Earlier studies suggest that improved blood compatibility might be attained by introducing hydrocarbon groups at the surface. We synthesized and characterized a series of polyurethanes in which a N-2,3-dihydroxypropyl-N'-octadecyl urea chain extender (ODCE) was incorporated into the poly(tetramethy1ene glycol) (PTM0)/4,4'-methylenebis(phenylene isocyanate) (MDI) system. Molecular weights of the polymers varied between 40,000 and 250,000. An electron spectroscopy for chemical analysis (ESCA) study of the ODCE polyurethane surface revealed a substantially enhanced hydrocarbon concentration compared to a control PTMO/ MDI/ethylene diamine (ED) polyurethane surface. Also, bulk composition analyses and ESCA data of the ODCE polymers indicated that the percentage of carbon was higher in the surface region than in the bulk. Thus, the ODCE polymer showed a marked increase in hard-segment concentration in the surface region compared to the bulk region and to the ED polymer. *Present address: A.

This paper describes a study on emulsifier‐free ultrasonically assisted in‐situ copolymerization method of acrylamide and styrene in the presence of CNT, resulting in stable and uniform dispersions. The dispersions prepared were found stable for several months. Thermogravimetric analysis (TGA) curves and conversion measurements provided an insight regarding the polymerization mechanism and the nanocomposites structure. Films prepared of the polymerization products resulted in some clear and transparent coatings. The polymerization method described is simple and very fast compared with the other literature reported methods. TGA was extensively used as an analytical tool for determination of the composition of acrylamide–styrene copolymers. TGA and differential scanning calorimetry indicate that the polymerization product is largely a poly(styrene‐co‐acrylamide), where the acrylamide fraction is attached to the CNT surfaces. The copolymer produced, with and without CNT, is essentially a block copolymer, where each block contains small amounts of the other comonomer. To the authors' best knowledge, this report is the first one describing the production of stable dispersions of CNT in surfactant‐free poly(styrene‐co‐acrylamide) emulsion. Copyright © 2013 John Wiley & Sons, Ltd.

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