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Metallocene‐Catalysed Copolymerisation of Ethylene with 10‐Undecenoic Acid: The Effect of Experimental Conditions
Author(s) -
Santos Jorge Moniz,
Ribeiro Maria Rosário,
Portela Manuel Farinha,
Pereira Sónia Gama,
Nunes Teresa Gouveia,
Deffieux Alain
Publication year - 2001
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20010701)202:11<2195::aid-macp2195>3.0.co;2-q
Subject(s) - comonomer , polymer chemistry , ethylene , polymerization , metallocene , catalysis , chemistry , polymer , organic chemistry
The copolymerisation of ethylene with 10‐undecenoic acid (UA) using the metallocene catalyst system Cp 2 ZrCl 2 /MAO was achieved. A reaction between the comonomer and MAO, prior to the copolymerisation, was used in order to protect, to some extent, the carboxylic group. The degree of MAO protection was found to be dependent on the Al/UA ratio used in the precontact mixture. The interaction between the two compounds was investigated by means of NMR spectroscopy. The influences of comonomer concentration in feed, Al/Zr mole‐ratio and polymerisation temperature on the copolymerisations, were investigated with respect to catalyst activity and to UA incorporation. Higher concentrations of UA in feed favour the incorporation rate but decrease the activity. The Al/Zr mole ratio shows a strong influence on activity, but not on the comonomer incorporation. Both the polymerisation activity and the UA incorporation rate present an optimal polymerisation temperature of around 40°C. DSC characterisation shows a decrease in the melting temperature of the polymers for increasing UA incorporations. Bimodal melting peaks, representative of polymer inhomogeneity, were observed for the highest UA incorporations.