Incorporation of POSS to improve thermal stability of bio‐based polymethacrylates by nitroxide‐mediated polymerization: Polymerization kinetics and characterization

Abstract

Nitroxide-mediated polymerization (NMP) was used to polymerize methacrylate-functionalized polyhedral oligomeric silsesquioxane, POSSMA, in a controlled manner with bio-based C13 methacrylate (C13MA) to improve the thermal stability of the latter by copolymerization (using 10 mol% acrylonitrile controlling comonomer). Kinetic experiments (80-110 C) revealed the relatively low ceiling temperature of POSSMA (135 C). Synthesis of poly(POSSMA-co-AN) with f AN,0 = 0.10 at 90 C resulted in low dispersity

Nitroxide mediated miniemulsion polymerization of methacryloisobutyl POSS: Homopolymers and copolymers with alkyl methacrylates

“…Increasing the initial molar ratio of POSSMA reduced the polymerization rate in the first 50 min of the reaction. This was observed previously by Marcinkowska et al [ 58 ] and Hajiali et al [ 24 ] for copolymerization of POSSMA with lauryl methacrylate (C12‐MA) or C13MA in homogeneous organic solvent.…”

“…[ 27,57 ] The plateau observed in the M n versus X plots here was previously observed in our study of POSSMA NMP using BlocBuilder alkoxyamine in toluene at 90°C and ATRP of POSSMA monomers at 60°C for conversions higher than 75%, which was attributed to the equal rates of polymerization and depolymerization at the given temperature. [ 24,27 ] The plateauing was not observed for monomer conversions with time (Figure 3a), which can be ascribed to the slow initiation of Dispolreg 007. [ 34,35,49 ] This can increase the possibility of initiation at higher conversions and result in improved conversions at the final stages of polymerizations.…”

“…POSSMA/C13MA NMP using BB alkoxyamine and 10 mol% AN as the controlling comonomer was previously performed in toluene at 90°C and the final conversion was considerably lower than in POSSMA/C13MA miniemulsion copolymerization using Dispolreg 007 alkoxyamine (85.4% < X Miniemulsion < 96.5% compare with 38% < X solution‐based < 81%). [ 24 ] The semi‐logarithmic kinetic plots for copolymerizations were shown in Figure 5a. All the plots obeyed first‐order kinetics.…”

“…Methacrylic POSS contain one or more methacrylic ligands, which enables free radical polymerization. Many studies have illustrated the successful radical polymerization (conventional, [ 17,18 ] atom transfer radical polymerization [ATRP], [ 19–21 ] reversible addition‐fragmentation chain transfer [RAFT] [ 22,23 ] and nitroxide mediated polymerization [NMP] [ 24,25 ] ) of methacrylic POSS. One of the methacrylic POSS compounds is 3‐(3,5,7,9,11,13,15‐heptaisobutylpentacyclo [9.5.1.…”

“…POSSMA‐rich copolymers with 10 mol% acrylonitrile (AN) or styrene (S) in the initial monomer mixture was previously synthesized in our research group using N‐(2‐methylpropyl)‐N‐(1‐(diethylphosphono‐2,2‐dimethylpropyl)‐O‐(2‐carboxylprop‐2yl)hydroxylamine) BlocBuilder‐MA (BB, Arkema). [ 24,25 ] Charleux et al [ 28 ] showed that the polymerization of methacrylate‐rich compositions (essentially mimicking homopolymerization) by BB alkoxyamine was feasible using a low concentration of controlling comonomer with a very low activation/deactivation equilibrium constant such as AN or S, which was thought to decrease the average equilibrium constant for activation/deactivation of the chains 〈 K 〉 and to also reduce cross‐disproportionation side reactions. [ 29–31 ]…”