Novel Precision Polyolefins from Living Coordinative Chain-Transfer Polymerization

Abstract

ABSTRACT

Title of Document: Novel Precision Polyolefins from Living Coordinative Chain-Transfer Polymerization

Rennisha R. Wickham

Doctor of Philosophy, 2012

Directed By: Professor Lawrence. R. Sita Department of Chemistry and Biochemistry

Polyolefins (POs), especially polyethene (PE) and polypropene (PP), are by far the largest volume synthetic polymers in the plastic industry, with annual global production exceeding 1.4 × 10<super>8</super> metric tons and projected to increase to 200 million tons by the year 2020 according to the 2007 National Petrochemical and Refiners Association Report. This is primarily due to their benign nature, excellent cost performance value, as well as ease of recycling, processing and fabrication. With societal dependence on polyolefins steadily increasing, efforts have been placed on the development of living coordinative chain-transfer polymerization (LCCTP) towards the large scale production of functionalized copolymers and block copolymers from commodity volume monomers, ethene (E) and propene (P) with &alpha;-olefins, cyclic and sterically encumbered olefin comonomers that could potentially be used as compatibilizers in polymer mixtures, thermoplastic elastomeric substitutes of EPDM rubber, and macro-initiators in anionic and free radical polymerizations methods. Copolymerizations of E and P with monomers that can be obtained in industrially significant volumes from renewable biomass-derived feedstocks or waste product streams are investigated. The diterpene &beta;-citronellene, represents an ideal target as a potential co-monomer since after incorporation through Ziegler-Natta enchainment of the terminal vinyl group, the remaining tri-substituted double bond is available for further chemical modification or cross-linking. Norbornene is also a desirable comonomer for ethene copolymerization as the resulting polyolefin materials are optically transparent and can be used as replacements for polycarbonates. Another non-conjugated diene, 1,5-hexadiene, has been utilized in conjunction with 1-hexene or 1-octene to produce rod-coil block copolymers that could potentially give way to polyolefins having new end-use properties through microphase separation into various nanostructures. Moreover, post-functionalization of PE and PP materials with I, N₃, OH, and PPh₃ etc., is investigated as a route towards the production of value-added polymers. Finally, this work utilizes aims to develop new spectroscopic and analytical tools for the structural analysis of hydrocarbons materials, as these properties directly influence the chemical and physical properties. Therefore, the practicality of MALDI-TOF MS as a routine characterization method for the evaluation of new polyolefins was probed. Overall this thesis will discuss the tailored synthesis, functionalization and characterization of ethene and propene based polymers.