Copolymerization of n-Butyl Acrylate with Methyl Methacrylate and PMMA Macromonomers by Conventional and Atom Transfer Radical Copolymerization

Abstract

The reactivity ratios of n-butyl acrylate (nBuA) with methyl methacrylate (MMA) and ω-methacryloyl-PMMA macromonomers (MM) in conventional and atom transfer radical copolymerization (ATRP) have been determined. For the copolymerization of nBuA with MMA, good agreement of the ratios is observed between conventional and controlled radical copolymerization, indicating that chemoselectivities in both processes are similar. The relative reactivity of the MM (1/r nBuA ) in conventional copolymerization is significantly lower than of MMA. It depends on the concentration of the comonomers but is not significantly influenced by the length of the MM. At high concentrations the relative reactivity decreases due to diffusion control of the MM addition. In ATRP the relative reactivity of the MM is much closer to the value of MMA. This is explained by the different time scales of monomer addition in both processes: whereas the frequency for monomer addition is in the range of milliseconds for conventional polymerizations, it is in the range of seconds or minutes in ATRP, thus diffusion control is less important here. This gives the opportunity to copolymerize at much higher concentrations than in conventional radical copolymerization. In addition, two-dimensional chromatography shows that the graft copolymers obtained by ATRP are much more homogeneous in terms of MWD and number of side-chains.Graft copolymers offer all properties of block copolymers but are usually easier to synthesize. Moreover, the branched structure leads to decreased melt Corresponding author.

Linear Control of Moisture Permeability and Anti-adhesion of Bacteria in a Broad Temperature Region Realized by Cross-Linking Thermoresponsive Microgels onto Cotton Fabrics

“…The random distribution of the monomers can be attributed to the similar polymerization reactivities of MEO 2 MA and OEGMA 300 , because both have almost the same molecular structure. 41,42 Similar to our previously investigated poly(acrylate)-based thermoresponsive polymers, 39,40,43−46 PMEO 2 MA possesses a relatively broad transition region. Consequently, it does not turn completely hydrophobic even when the external temperature is above the TT PMEO 2 MA .…”

“…Thereby, no enrichment of a certain monomer is observed on the microgels surface. The random distribution of the monomers can be attributed to the similar polymerization reactivities of MEO 2 MA and OEGMA 300 , because both have almost the same molecular structure. , …”

Design of Oligo(ethylene glycol)-Based Thermoresponsive Polymers: an Optimization Study

“…However, in conventional radical polymerizations, polymer chains are initiated all along the reaction and, therefore, if the co-monomers have different reactivities, strong chainto-chain deviations of composition can be expected. On the other hand, in a living polymerization, all the chains are initiated simultaneously and, therefore, exhibit rather homogeneous chain-to-chain compositions [60,61].…”

Synthesis of Poly(OEOMA) Using Macromonomers via “Grafting-Through” ATRP

“…Atom transfer radical polymerization (ATRP) is a powerful reversible-deactivation radical polymerization (RDRP) technique. − ATRP allows for the polymerization of a wide range of monomers, forming copolymers with predetermined molecular weight (MW), narrow molecular weight distribution (MWD), and controlled molecular architecture such as block, gradient, hyperbranched, graft, comblike, and star copolymers. − , ATRP has been conducted in many organic solvents in the presence of various functional groups. Recently, macromonomers (MMs) were used for the preparation of functional graft copolymers via an ATRP “ grafting-through ” method. − Branched polymers such as stars and graft copolymers generally have lower viscosity than polymers with linear structures of the same MWs because of their smaller hydrodynamic volume. − Because of their structural tunability, such as copolymer composition, backbone or side chain length, and grafting density, they have many potential applications. − MMs with hydrophilic and biocompatible properties, such as those based on poly­(ethylene glycol) (PEG), have been used for biomedical applications. , …”