Solvent Effects on Kinetics of 2-Hydroxyethyl Methacrylate Semibatch Radical Copolymerization

Solvent Effects on Radical Copolymerization Kinetics of 2-Hydroxyethyl Methacrylate and Butyl Methacrylate

2-Hydroxyethyl methacrylate (HEMA) is an important component of many acrylic resins used in coatings formulations, as the functionality ensures that the chains participate in the cross-linking reactions required to form the final product. Hence, the knowledge of their radical copolymerization kinetic coefficients is vital for both process and recipe improvements. The pulsed laser polymerization (PLP) technique is paired with size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR) to provide kinetic coefficients for the copolymerization of HEMA with butyl methacrylate (BMA) in various solvents. The choice of solvent has a significant impact on both copolymer composition and on the composition-averaged propagation rate coefficient (k_p,cop). Compared to the bulk system, both n-butanol and dimethylformamide reduce the relative reactivity of HEMA during copolymerization, while xylene as a solvent enhances HEMA reactivity. The magnitude of the solvent effect varies with monomer concentration, as shown by a systematic study of monomer/solvent mixtures containing 50 vol%, 20 vol%, and 10 vol% monomer. The observed behavior is related to the influence of hydrogen bonding on monomer reactivity, with the experimental results fit using the terminal model of radical copolymerization to provide estimates of reactivity ratios and k_p,HEMA.

Analytical and advanced kinetic models for characterization of chain-growth copolymerization: the state-of-the-art

A detailed overview is given on the currently developed analytical and advanced kinetic models to calculate the main bulk/solution chain-growth copolymerization characteristics.

The Effect of Hydrogen Bonding on Radical Semi-Batch Copolymerization of Butyl Acrylate and 2-Hydroxyethyl Acrylate

The radical copolymerization of butyl acrylate (BA) and 2-hydroxyethyl acrylate (HEA) was investigated under batch and semi-batch operations, with a focus on the influence of hydrogen-bonding on acrylate backbiting. The effect of hydrogen bonding on HEA to BA relative incorporation rates during copolymerization, previously seen in low-conversion kinetic studies, was also observed under high-conversion semi-batch conditions. However, overall reaction rates (as indicated by free monomer concentrations), polymer molar masses, and branching levels did not vary as copolymer HEA content was increased from 0 to 40 wt % in the semi-batch system. In contrast, introduction of a H-bonding solvent, n-pentanol, led to an observable decrease in branching levels, and branching levels were also reduced in batch (co)polymerizations with HEA. These differences can be attributed to the low levels of unreacted HEA in the starved-feed semi-batch system.

Hydrogen bonding in radical solution copolymerization kinetics of acrylates and methacrylates: a comparison of hydroxy- and methoxy-functionality

Experimental data obtained via pulsed laser polymerization are used to distinguish the influence of H-bonding on kinetic chain-growth parameters from that of side-chain heteroatoms.

The influence of hydrogen bonding on radical chain-growth parameters for butyl methacrylate/2-hydroxyethyl acrylate solution copolymerization

Pulsed laser polymerizations coupled with size exclusion chromatography (PLP-SEC) and NMR analyses were performed to determine radical kinetic parameters for BMA/HEA, with a focus on the effect of solvent choice and H-bonding on both copolymer composition and copolymer-averaged propagation rate coefficients.

Pulsed-laser and quantum mechanics study of n-butyl cyanoacrylate and methyl methacrylate free-radical copolymerization

Improved control over polymer microstructure is achieved by radical copolymerization of n-butyl cyanoacrylate with methacrylates.