The Atrp System The Chlorine Styrene And Methyl Acrylate Gradient Copolymers Synthesis And Characterization

The copolymers of p-chlorostyrene (p-C1St) and methyl acrylate (MA) were prepared using atom transfer radical polymerization (ATRP) catalyzed by CuBr / N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) in bulk at 90℃ were studied in system. Plots of ln([M]₀/[M]) vs time and M|-_n M_n vs monomer conversion were linear. The copolymer polydispersities were low. The result show the copolymerzation are "living". Reactivity ratios r_s=1.2 r_A=0.09 were obtained by ¹H NMR spectra. The gradient copolymers could be obtained due to the difference of reactivity ratios of the two monomers.¹³C NMR was used to characterizaties the structure of gradient copolymers at different conversion. The triad sequences were determined by using the C1 ipso region (aromatic Cl carbon) and the carbonyl resonance frequencies from the spectra. The triad concentrations were obtained by the spectra. The dyad concentrations in the copolymers were obtained from them. The varieties of triad and dyad concentration fractions with conversion were first introduced to describe the gradient copolymers. In order to characterize the gradient structure of the gradient copolymers, we define a parameter, which be called the gradient index (I). All kinds of gradient copolymers in structure were characterized by the gradient index (I), and the result show it is suitable for characterize the gradient structure of the gradient copolymers.