Kinetic modeling of the molecular architecture of cross-linked copolymers synthesized by controlled radical polymerization techniques

Abstract

A recently developed general kinetic approach, based on population balances in terms of generating functions, is applied to the modeling of the molecular architecture of branched copolymers produced through controlled radical polymerization (CRP) techniques, namely nitroxide-mediated radical polymerization (NMRP) and atom-transfer radical polymerization (ATRP). Thanks to this method, it is possible to carry out dynamic predictions of distributions of molecular weights, sequence lengths and z-average mean square radius of gyration of the products, both before and after gelation (whenever it occurs) with consideration of complex kinetic schemes. The model chemical systems styrene + divinylbenzene (S/DVB) and methyl methacrylate + ethylene glycol dimethacrylate (MMA/EGDMA) are experimentally investigated in order to assess the prediction capabilities of the aforementioned approach. Measurements of absolute molecular weights and z-average radius of gyration of the copolymers are performed for different times of polymerization using a SEC system with a refractive index detector coupled with MALLS. It is shown that the proposed computational tool can enhance the possibility of better design of these complex materials but additional studies concerning the impact of intramolecular cyclizations on the structure of materials synthesized at diluted conditions are needed.