| 摘要 |
The present depicts a polymerization procedure in micro-emulsion wherein a part of the monomer is added to initiate the reaction and the rest of the monomer is semi-continuous, for obtaining poly(butyl acrylate) latices with diameters of particle smaller than 50 nm, upper polymer contents to the 20% in weight and monomer/surfactant (weight/weight) relations of more than 15. The reaction times are of 2 hours or less and at the end of the process conversions of more than 99% are reached. The reaction temperature may be of 30 to 80°C. The initiators can be water soluble such as dihydrochloride 2, 2°-azobis (2-amidinopropane) (V-50), potassium persulphate (KPS) or redox system persulphate of sodium potassium-bisulfite (K2S208-NaHS03). The initiator concentration can be of 0.1 to 3.0% in weight regarding the total monomer. The surfactants could be cationic like bromide of dodeciltrimethylamonio (DTAB) and bromide of hexadeciltrimethylamonio (CTAB), or anionics like sodium dodecil sulphate (SDS) and sodium bis (2-ethylhexyl) sulphosuccinate (AOT) and can be use in a single or mixed way. The relations surfactant/water used can go from 1/99 up to 20/80 (weigh/weight).
|
