Synthesis and unperturbed dimensions of poly(diphenylmethyl methacrylate)

The synthesis, fractionation, and characterization of poly(diphenylmethyl methacrylate) (PDPMM) are described. Analysis of tacticity by 13C nuclear magnetic resonance (NMR) revealed a high (25%) isotactic content. Results of low‐angle light scattering and intrinsic viscosity measurements in toluene indicate that PDPMM chains behave as random coils and that toluene is a thermodynamically good solvent. The characteristic ratio C∞ of the chains was determined from viscosity measurements in a near‐theta solvent, 3‐heptanone at 45°C. The corresponding value of C∞ = 14.0 is consistent with previous work on poly(triphenylmethyl methacrylate), C∞ = 20.3, and poly(benzyl methacrylate), C∞ = 10.0, and reflects the bulkiness of the side group and the increase in isotactic content of the chains with increasing substitution.