| 학회 | 한국고분자학회 |
| 학술대회 | 2002년 가을 (10/11 ~ 10/12, 군산대학교) |
| 권호 | 27권 2호, p.253 |
| 발표분야 | 고분자 합성 |
| 제목 | Theory of Metallocene Catalyzed Ethylene-Styrene Copolymerization |
| 초록 | Ethylene (E)-styrene (S) copolymerization with constrained geometry catalysts (CGCs) were theoretically studied by a mean field theory. Two kinds of CGCs, i.e., MCGC (mononuclear CGC) and DCGC (dinuclear CGC), were employed for model catalysts in order to investigate the effect of ligand structure on the reaction behavior of the E-S copolymerization. Energetics of reactants, π-complexes, transition states, and products during the insertion of ethylene and/or styrene monomers into the metal-Cα bond of the CGCs were analyzed by density functional method and used to calculate reactivity ratios between monomer units. In addition to this, a free energy of a globule regarded as "micrireactor" is formulated to take into account all the pairwise interactions present in the globule, assuming that the globule has a boundary permeable to the monomers from outside. The sequence and the compositions of the copolymer were then predicted by minimizing free energy with respect to the fraction of monomer species in the globule and the results were compared to that obtained from experiment. From these theoretical calculations, it is found that the discrepancy between the composition of copolymers and monomer free ratio is a result of interplay between the reactivity ratio and the pairwise interaction parameters of the monomers and solvents, which determines the compositions of the monomer species inside a globule. |
| 저자 | 양성훈1, 허 준2, 조원호, 노석균* |
| 소속 | 1서울대, 2*영남대 |
| 키워드 | ethylene-styrene copolymerization; mean field theory; density functional |
