Maria Marques

Universidade Federal do Rio de Janeiro, Instituto de Macromoléculas Professora Eloisa Mano-IMA-UFRJ Av. Horácio Macedo, 2030, Centro de Tecnologia Bloco J. Cidade Universitária. Rio de Janeiro, RJ, Brazil

[ 1 ] - Influence of diethyl zinc on ethylene-norbornene copolymerization

Ethylene-norbornene copolymers were synthesized with a homogeneous catalyst system based on bis(imino) pyridine iron with the addition of diethyl zinc (DEZ) as alkyd transfer agent to promote immortal copolymerization. The addition of DEZ did not influence the catalytic activity in copolymerization with 7.5 mmol of norbornene (NB), but in the reactions with 70 mmol, the comonomer promoted an in...

[ 2 ] - In situ stabilization of polypropylene by lignin using a Ziegler-Natta catalyst

A fourth-generation Ziegler-Natta catalyst was prepared to synthesize polypropylene (PP), which was stabilized by in situpolymerization employing lignin as antioxidant. The antioxidant properties of lignin were compared with those of the commercial antioxidant Irganox 1010. The presence of lignin in the reaction medium slightly decreased the catalytic activity of the reaction. The isotacticity ...