Addition of thiol-ended polystyrene to acrylates

Abstract

Polystyrene containing end thiol groups has been prepared via the aminolysis or alcoholysis of its trithioester under conditions established previously for the model reaction of bis(1-phenylethyl) trithiocarbonate. The aminolysis of polystyrene with M _n = 8.2 × 10³ by n-hexylamine at 100°C in toluene led to the formation of a polymer with M _n = 4 × 10³ and a polydispersity coefficient of 1.13. The unimodal molecular-mass distribution of the polymer and its narrow polydispersity that is nearly equal to the initial polydispersity suggest that all trithiocarbonate groups of the starting polystyrene are involved in hydrolysis. The addition of 1-phenylethylthiol and thiol-ended polystyrene to methyl acrylate and methyl methacrylate via the Michael hydrolysis has been studied, and it has been demonstrated that the addition proceeds quantitatively at room temperature. The addition may be directly implemented with the use of dithioesters in the presence of the catalytic amount of a base; therefore, the stage of thiol synthesis can be eliminated. For the quantitative addition to acrylates, the preliminary hydrolysis of the polymer is however preferable.