(370e) Macroscopic Modeling of Spontaneous-Thermal Polymerization of n-Butyl Acrylate

Acrylates are used to produce acrylic binder resins, which are the key components of paint and coating formulations [1-4]. High-temperature (>100ºC) free-radical polymerization processes have been developed to produce high solid-level, low molecular weight, and environmental-friendly acrylic resins [5, 6]. Using less thermal initiators such as organic peroxides and isonitriles in high-temperature polymerization has been desired due to relatively higher cost of the initiators and negative impact of unreacted initiators on the end-product quality [7].

Previous studies [8, 9] have explored the nature of initiating species in thermal polymerization of alkyl acrylates by using electrospry ionization-Fourier transform mass spectrometry (ESI-FTMS) and nuclear magnetic resonance (NMR) spectroscopy. These studies could not determine any specific mechanism for initiation in spontaneous thermal polymerization of alkyl acrylates. More recently, using computational quantum chemistry, it was shown [10, 11] that monomer thermal self-initiation can contribute to initiation in alkyl acrylate polymerization. Rantow et al. [9] estimated the kinetic parameters of initiation reactions in spontaneous polymerization of n-butyl acrylate using a macroscopic mechanistic modeling approach. However, this study could provide no fundamental understanding of initiation mechanism in the spontaneous thermal polymerization. Before this work, there was no study on the extent of the contribution of dissolved oxygen to initiation in spontaneous polymerization of n-butyl acrylate.

This work presents a detailed macroscopic mechanistic model of a batch reactor in which spontaneous thermal polymerization of n-butyl acrylate occurs. Monomer conversion measurements from batch experiments are used to estimate the kinetic parameters of all initiation reactions- dissolved oxygen and monomer self-initiation. The reaction rate constants obtained through this macroscopic modeling are compared with those obtained via quantum chemical calculations.

References

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