Surface Modification of Pigments with Temperature-Responsive Polymer Grafted by Plasma-Induced Polymerization.

Abstract

In order to develop temperature-responsive dispersing systems, we have grafted poly(N-isopropylacrylamide) (PNIPA), which is a temperature-responsive polymer having a lower critical solution temperature (LCST) at 32°C, onto carbon black (CB) by plasma-induced graft polymerization technique. CB was treated with H2O and/or O2 plasma, to which aqueous solution of the monomer (NIPA) was introduced, resulted in simultaneous graft polymerization. The dispersibility of the PNIPA-grafted CB in water at 25 and 35°C was investigated by the measurement of the transmittance of visible light (500nm). The most of the PNIPA-grafted CB showed better dispersibility at 25°C (below the LCST) than at 35°C (above the LCST). In many graft polymerization conditions, CB grafted in 2wt% of the monomer concentration with ultrasonic irradiation at room temperature showed the most clear temperature response of the dispersibility in water.