Structure, morphology and interfacial behaviour of ethylene/methacrylate copolymers

• Published in: Journal of polymer research Vol. 20; no. 3; pp. 1 - 16
• Main Authors: Matos, Inês, Ascenso, José R., Lemos, MANDA, Fan, Zhiqiang, Yuan, Jianchao, Farinha, José Paulo S., Lemos, Francisco, Gonçalves da Silva, Amélia M. P. S., Marques, Maria M.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.03.2013; Springer Nature B.V
• Subjects: Catalysis; Catalysts; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Copolymers; Ethylene; Industrial Chemistry/Chemical Engineering; Monolayers; Nuclear magnetic resonance; Original Paper; Polyethylenes; Polymer Sciences; Polymethyl methacrylates; Copolymers; Polar monomers; Monolayer studies, AFM; Methylmethacrylate
• ISSN: 1022-9760; 1572-8935
• DOI: 10.1007/s10965-013-0090-z

Two alpha-diimine monometallic Ni catalysts, catalyst 1 and catalyst 2 , were studied in the copolymerization reaction of ethylene (E) with methyl methacrylate (MMA). The reaction products of these reactions were characterized using not only the usual techniques such as NMR, GPC and DSC but also the Langmuir balance and AFM. 1 H and 13 C NMR spectra revealed that both copolymers and mixtures of E and MMA (in a range of 20–70 mol% of MMA) could be obtained with these catalysts. A better insight of the products was possible with 1 H DOSY NMR. Since p(E-MMA) copolymers comprising hydrophobic PE blocks and surface active PMMA blocks are amphiphilic, the Langmuir monolayer technique provided further information on the two-dimensional phase behavior of copolymer monolayers at the air-water interface. Additionally, AFM topographic images of the Langmuir-Blodgett (LB) monolayers deposited on mica substrates clearly showed that the morphology of the copolymer LB monolayer is quite different from the corresponding mixture of PE and PMMA homopolymers. These techniques together with molecular modeling calculations allowed us to conclude that with catalyst 2 it was possible to obtain a true block copolymer by a mechanism involving a cationic ester-enolate metal complex as the active species.