Nuttaporn Wisutsri. Atom transfer radical polymerization of methyl methacrylate and styrene catalyzed by CuCItripodal ligands bearing ferrocene and benzyl moieties. Master's Degree(Applied Analytical and Inorganic Chemistry). Mahidol University. Mahidol University Library and Knowledge Center. : Mahidol University, 2009.
Atom transfer radical polymerization of methyl methacrylate and styrene catalyzed by CuCItripodal ligands bearing ferrocene and benzyl moieties
Abstract:
Atom transfer radical polymerization (ATRP) is one of the
controlled/living radical polymerization (CRP) processes giving rapid growth due to
the successful polymerization with controlled molecular weight, well defined
compositions, architectures, and functionalities of polymers. The ATRP process is
involved in the chemical exchange between the metal catalyst active species and the
oxidized metal complex deactivated species, therefore, the catalyst (including
transition metals and ligands) in ATRP plays a crucial role in the catalytic pathway.
Ligands play a great role in ATRP in tuning the activity of the metal center. Copper(I)
and copper(II) complexes with nitrogen-based tridentate ligands are commonly used
in ATRP. Herein, the ATRP of methyl methacrylate (MMA) is catalyzed by using
CuCl/TRENFcImine as a catalyst and initiated by using 1-chloro-1-phenylethane
(PECl) as an initiator. The results exhibited good catalyst activity with high molecular
weight. In addition, Cu(II) was used to reduce the concentration of radicals through a
deactivation process using the same experimental conditions. Although 2 mol%
CuCl2·2H2O with respect to CuCl was added, the PDI of all polymers were still higher
than a conventional radical. Moreover, the trace of water in CuCl2·2H2O accelerated
the rate of propagation leading to a higher molecular weight. Furthermore, three
catalyst complexes with newly synthesized ligands were investigated for ATRP of
MMA and styrene (St). The order of polymerization rates of both MMA and St was
TREN-2Cl-Amine < TREN-3Cl-Amine < TREN-4Cl-Amine. The polymerizations
using these ligands led to broader molecular weight distributions and poor agreement
between theoretical and experimental Mn. In addition, the end groups of chains using
TREN-4Cl-Amine as a ligand to polymerize MMA were also analyzed in this study.
The result revealed that the order of polymerization rates used PECl as an initiator
more than ethyl-4-chlorobutylate. Unfortunately, polymerizations using these
initiators led to an uncontrolled polymerization and the molecular weights were higher
than the prediction