Synthesis of Functional Polyolefins using Metallocenes: A Comprehensive Review

Abstract

The copolymerization mainly of ethylene and propylene with various polar functional comonomers, using various metallocenes and the methylaluminoxane (MAO) cocatalyst, has been primarily reviewed from the perspective of the following two subjects. One is the influence of the various functional groups on the copolymerization reactions, and the properties of the resulting products; the other is the areas of future research. The functional groups have been classified into oxygen-, nitrogen-, and halogen-containing moieties; borane-containing α-olefins; silanes; dienes; cyclic olefins; as well as styrene and its various derivatives. The following areas—synthesis of easily soluble functional cooligomer/copolymer; products with uniform distribution of the comonomer; establishment of relation among the catalyst structure and the various steps of copolymerization (initiation, propagation, and chain termination); the degradation and stabilization study of the functional copolymers and the correlation of the same with the catalyst structure; the application of supported metallocenes to synthesize the resulting polymer; the minimization of multi-step synthesis; and the development MAO cocatalyst formulation (to improve the activity and comonomer incorporation)—have been identified to be the subjects of future research, which will be of special importance to the researchers working in functional polyolefins.

Keywords:

• metallocenes
• functional polyolefins
• protection-deprotection technique
• research challenges

Acknowledgement

The authors thankfully appreciate the support provided by the Research Institute and the Center of Research Excellence in Petroleum Refining & Petrochemicals (CoRE-PRP, established by the Saudi Ministry of Higher Education), King Fahd Univeristy of Petroleum & Minerals, Dhahran, Saudi Arabia. The financial support provided by Ciba Plastic Additive Segment at Basel, Switzerland, under Project Number CRP 2219, is gratefully acknowledged. The technical assistance of Mr. Anwar Hossaen is appreciated.