Thermokinetic parameter estimation of RAFT solution polymerization of dodecyl methacrylate by reaction calorimetry
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ORIGINAL PAPER
Thermokinetic parameter estimation of RAFT solution polymerization of dodecyl methacrylate by reaction calorimetry Nicolas Brodu1 · Imed Ben Talouba1 · Isabelle Lahoud1 · Laurent Balland1 · Nordine Mouhab1 Received: 16 June 2020 / Accepted: 31 October 2020 © Institute of Chemistry, Slovak Academy of Sciences 2020
Abstract The kinetics of RAFT polymerization of a dodecyl methacrylate controlled by a trithiocarbonate as a chain transfer agent (CTA) are studied by measuring the thermal profile in an RC1-RTCal reaction calorimeter. Contrary to classical methods such as electron spin resonance spectroscopy, the equilibrium constants related to the addition and fragmentation steps are estimated for a high degree of polymerization. The estimation method consists of a comparison between the measured thermal profiles and those built from models reflecting the instantaneous balances of mass and energy. The influence of the concentration of the transfer agent on the characteristics of the polymer (molar mass and dispersity) was also studied at different reaction temperatures. An increase in the concentration of CTA decreases the viscosity of the medium due to a more homogeneous distribution of the small sizes of the polymers. The influence of reaction temperature on the characteristics of polymers is reduced in the presence of CTA. Keywords Reaction calorimetry · Thermo-kinetic parameters estimation · RAFT polymerization · Dodecyl methacrylate Abbreviations ATPR Atom transfer radical polymerization Ak Pre-exponential factor of Arrhenius law CTA Chain transfer agent CPDTC 2-Cyano-2-propyl dodecyl trithiocarbonate DDMA Dodecyl methacrylate Ek Activation energy of Arrhenius law ESR Electron spin resonance spectroscopy kad/k−ad Addition constants of pre-equilibrium kaddP/k−addP Addition constants of RAFT equilibrium kβ/k-β Fragmentation constants of pre-equilibrium kd Initiator decomposition constant kex/k−ex RAFT equilibrium constant ki Initiation constant kp Propagation constant ktr Transfer constant Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11696-020-01412-x) contains supplementary material, which is available to authorized users. * Nicolas Brodu nicolas.brodu@univ‑rouen.fr 1
Laboratoire de Sécurité Des Procédés Chimiques (LSPC), Normandie Université, Université de Rouen-Normandie/ INSA-Rouen, 76801 Saint‑Étienne‑du‑Rouvray Cedex, France
kt Termination constant Ip Dispersity mM (tend) Monomer mass at the end mM (t0) Monomer mass at the beginning RAFT Reversible addition-fragmentation chain transfer polymerization rk Individual reaction rate RDRP Reversible deactivation radical polymerization SFRP Stable free radical polymerization TBEC Tert-Butylperoxy 2-ethylhexyl carbonate TGA Thermogravimetric analysis Tj Jacket temperature (°C) TR Reaction temperature (°C) Vr Reaction volume X Conversion of monomer X(tend) Final monomer conversion ∆Hk Molar enthalpy associated to reaction step k
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