Modeling the propagation, chain transfer and tacticity in free radical polymerization

Abstract

In this study, the free radical polymerization of methyl methacrylate (MMA) and NIsopropylacrylamide (NIPAM) is investigated by using Density Funtional Theory (DFT). In the first part, the role of thiophenols as chain transfer agents in the polymerization of methyl methacrylate (MMA) is investigated. In many applications, methyl methacrylate is an excellent substitute for glass and it has good mechanical properties. Thiophenols act as chain transfer agents for controlling the molecular weights, thereby the physical properties of some common acrylates such as methyl methacrylate. The correlation between the calculated trend of the chain transfer constants and the experimental results has been reproduced with the MPWB1K/6-311+G(3df,2p) methodolgy. In the second part of this study the solvent effect on the tacticity of the free radical polymerization of N-Isopropylacrylamide is investigated. Tacticity strongly influences the solution property of Poly(N-Isopropylacrylamide) (PNIPAM). This polymer is a temperature-responsive polymer and called intelligent polymer. It undergoes a reversible phase transition at its lower critical solution temperature (LCST) which is around the body temperature. So, it is used in many areas like drug release. The effect of methanol as a solvent in the polymerization rate and the tacticity of PNIPAM is studied by density functional theory (DFT).