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Title: Development of organocatalytic strategies for controlled ring-opening polymerisation for producing biodegradable polyesters and polycarbonates
Author: Kuroishi, Paula K.
ISNI:       0000 0004 8505 2212
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2019
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This thesis investigates organocatalytic ring-opening polymerisation (ROP) approaches for the controlled synthesis of biodegradable polymers by exploring the post-polymerisation modifications of pendent groups and by photochemical regulations. Chapter 1 reviews the organocatalysts developed for ROP, including the mechanistic aspects involved in the polymerisation. In addition, an overview of photocatalysed ROPs and the photocatalysts that can be potentially applied for this strategy is presented. Chapter 2 describes the selective carbonate ROP of trimethylenepropane oxirane ether carbonate monomer by using 1,5,7-triazabicyclo[4.4.0]dec-5-ene as organocatalyst. Post-polymerisation modifications of the pendent epoxide group with a range of nucleophiles demonstrate to be especially effective for benzylamine, chlorine and aromatic thiols. Chapter 3 demonstrates the high catalytic activity of 1,1,3,3-tetramethylguanidine (TMG) towards the ROP of L-lactide, and of δ-valerolactone and ε-caprolactone when a thiourea cocatalyst is utilised. In addition, the photoinduced ROP is explored by protecting TMG with a photosensitive group and the system is shown to provide temporal control to the polymerisation. Chapter 4 details the synthesis a bicyclic monomer analogue to lactide that would potentially crosslink via ROP to provide spatial resolution to the photocatalyst system. The monomer is obtained from the synthesis of an allyl-functional lactide, and subsequent thiol-ene reaction with a dithiol to form a bis(cyclic diester). Chapter 5 describes the efforts in preparing a resin formulation composed of the bis(cyclic diester) prepared in Chapter 4 and the photocatalyst developed in Chapter 3 to achieve spatial control. Network materials with various mechanical properties could be obtained by using the crosslinker, poly(L-lactide) oligomers and TMG as a catalyst, although no curing was observed when utilising photocatalysts. Chapter 6 summarises the key findings of Chapters 2 to 5 and presents opportunities for future investigations in the area of research of this thesis. Chapter 7 provides the experimental protocols and characterisation data of the compounds and materials prepared in this thesis.
Supervisor: Not available Sponsor: Conselho nacional de desenvolvimento cientifico e tecnologico
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QD Chemistry