Unit:
Τομέας ΙΙΙ [Ανόργανη Χημεία – Ανόργανη Χημική Τεχνολογία – Περιβαλλοντική Χημεία]Library of the School of Science
Author:
Ραπτόπουλος Γρηγόριος
Dissertation committee:
Πατρίνα Παρασκευοπούλου Επίκουρη Καθηγήτρια
Original Title:
Catalytic Polymerization of Olefins and Cycloolefins with Transition Metal Complexes
Translated title:
Καταλυτικός Πολυμερισμός Ολεφινών και Κυκλοολεφινών με Σύμπλοκα των Στοιχείων Μεταπτώσεως
Summary:
In this thesis we study two types of metal-mediated polymerization reactions:
Controlled Radical Polymerization (CRP) and Ring Opening Metathesis
Polymerization (ROMP).
CRP. We studied the catalytic activity of a family of tripodal CoII and MnII
complexes bearing trianionic triphenylamido-amine ligands towards CRP of
styrene and methyl methacrylate. CoII complexes were more reactive than MnII
complexes, with the steric factor playing an essential role in their reactivity
and control over the polymerization. In many cases polymers featured bimodal
molecular weight distributions, which indicate that two parallel mechanisms may
be in operation.
ROMP. We used the bimetallic compound Na[W2(μ-Cl)3Cl4(THF)2]·(THF)3 ({W2}, {W 3
W}6+, a΄2e΄4) for the synthesis of new polymeric materials. {W2} is a highly
efficient room-temperature initiator for the ROMP of norbornene (NBE) and some
of its derivatives. We synthesized statistical NBE/NBD (NBD: norbornadiene)
copolymers, which combine the properties of linear and crosslinked polymers.
The catalytic activity of {W2} can be improved by addition of small amounts of
phenylacetylene (PA) as co-initiator. Both catalytic systems ({W2} and {W2}/PA)
provided polymers with high-cis content. We investigated the reactivity of
{W2}/PA and we used this system for the synthesis of highly crosslinked
poly(dicyclopentadiene) (PDCPD) gels via ROMP of dicyclopentadiene (DCPD);
their structure and properties were compared to those of PDCPD gels obtained
using the commercially available WCl6 and the well-established 1st and 2nd
generation Ru-based Grubbs’ catalysts. The configuration of the polymeric chain
plays a key role in the swelling behavior of those PDCPD dry-gels in organic
solvents, which was studied extensively and exploited for the estimation of
Hansen Solubility Parameters (HSP) of mostly-cis PDCPD and for the separation
of chlorinated solvents from water. Therefore, it is concluded that {W2}/PA
shows unique advantages in terms of stereochemistry, properties and potential
applications of PDCPD gels over the mononuclear W- and Ru-based catalytic
systems.
Keywords:
Controlled Radical Polymerization, Ring Opening Metathesis Polymerization, Metal-Metal Bonds, Crosslinked Polymers, Gel Swelling
Number of index pages:
17-25
Number of references:
141
