Synthesis and Characterisation of Poly(vinyl alcohol) based materials for use within Personal Products

Abstract

Cationic polymers based upon poly(vinyl alcohol) (PVA) are synthesised with various levels of charge densities, molecular architectures and hydrophobicities. Furthermore, macroinitiators incorporating PVA segments are synthesized and subsequently used for single electron transfer - living radical polymerisation (SET-LRP) for the synthesis of a range of graft copolymers.
Chapter 1 is a general introduction on cationic polymers, their use within conditioning shampoo formulations and the chemical properties required for this application. The polymerisation techniques: ring-opening polymerisation and reversible deactivation radical polymerisation (RDRP); as well as the polymeric materials: PVA and polyglycerol are also discussed.
Chapter 2 involves the synthesis of cationic PVA through either etherification or esterification reactions. The etherification of PVA using either glycidyltrimethylammonium chloride (GTMAC) or 1,2-chlorohydroxypropyltrimethyammonium chloride (CHPTMAC) to synthesise poly[(vinyl alcohol)-ran-(vinyl, 2-hydroxypropyl ether trimethylammonium chloride)] (P[VA)-r-(VETMAC)]) is investigated. The charge densities of the polymers synthesised by slowing the rate of reaction with GTMAC were determined to be greater than the charge densities claimed in the literature. The synthesis of poly(vinyl betaine) (PVB) via the synthesis of poly(vinyl chloroacetate) as an intermediate is discussed, as well as attempts to control the charge density of the resulting PVB. The charge density of the synthesised polymers were determined using UV-Vis spectroscopy and by nuclear magnetic resonance (NMR) spectroscopy.
Chapter 3 discusses the synthesis of a novel hyperbranched graft copolymer, poly[(vinyl alcohol)-graft-(hyperbranched glycerol)] (P[(VA)-g-(hPG)]). The effects of the reaction conditions on the mole fraction of hyperbranched polyglycerol (x(hPG)), the degree of branching (%DB) and the degree of substitution (%DS) were all monitored for the water solvated reactions. The synthesis of P[(VA)-g-(hPG)] in organic solvents is also discussed. Furthermore, comparisons between P[(VA)-g-(hPG)] and physical blends of PVA and hyperbranched polyglycerol are also made.
Chapter 4 entails the synthesis of cationic polymers based upon P[(VA)-g-(hPG)] synthesised in Chapter 3. Poly[(vinyl alcohol)-ran-(vinyl,2-hydroxypropyl ether trimethylammonium chloride)-graft-(hyperbranched polyglycerol-2-hydroxypropyl ether trimethylammonium chloride)] (P[(VA)-r-(VETMAC)-g-(hPG-PETMAC)]) was synthesized from the reaction between P[(VA)-g-(hPG)] as the macroinitiator and GTMAC. The charge density of the resulting polymer was found to increase with increasing x(hPG) in themacroinitiator; charge densities up to 5.4 meq g-1 were determined. Furthermore, the synthesis of poly[(vinyl betaine)-graft-(hyperbranched polyglycerol betaine)] is also discussed.
Chapter 5 describes the synthesis of hydrophobic derivatives of the polymers synthesized in the previous chapters using epoxyoctane to synthesise poly[(vinyl alcohol)-ran-(vinyl, 2- hydroxy octyl ether)], poly[(vinyl alcohol)-ran-(vinyl, 2-hydroxy octyl ether)-ran-(vinyl, 2- hydroxypropyl ether trimethylammonium chloride)], poly[(vinyl alcohol)-ran-(vinyl, 2- hydroxy octyl ether)-graft-(hyperbranched polyglycerol-2-hydroxyoctyl ether)] and poly[(vinyl, 2-hydroxy octyl ether)-ran-(vinyl, 2-hydroxypropyl ether trimethylammonium chloride)-ran-(vinyl alcohol)-graft-(hyperbranched polyglycerol)-(2-hydroxypropyl ether trimethylammonium chloride)/(2-hydroxy octyl ether)]). The hydrophobicity of the synthesised polymers is measured based upon their contact angle and aqueous solubility.
Chapter 6 focuses on the synthesis of macroinitiators for RDRP containing PVA and poly(vinyl, 2-bromopropionate) (PVBrP) repeat units. 2-bromopropionic anhydride was synthesised for the reaction with PVA. Poly[(vinyl, 2-bromopropionate)-ran-(vinyl2- butyral)] was synthesised when the reaction was carried out in butanone. However when 1,4-dioxane was used as the reaction solvent poly[(vinyl alcohol)-ran-(vinyl, 2- bromopropionate)] (P[(VA)-r-(VBrP)]) was successfully synthesised, with 62% or 79% initiating groups (PVBrP groups).
Chapter 7 details the synthesis of graft copolymers by SET-LRP, using P[(VA)-r-(VBrP)] macroinitiators which were synthesised in Chapter 6. Methyl acrylate was polymerised with P[(VA)-r-(VBrP)] macroinitiators containing 62% or 79% initiating sites (PVBrP), with a molecular weight of 2.31 x 106 gmol-1 determined by atomic force microscopy. Hydroxyethyl acrylate was polymerised with P[(VA)-r-(VBrP)] macroinitiator containing 62% initiating sites to synthesise poly[(vinyl alcohol)-ran-(vinyl 2-bromopropionate)-graft- (hydroxyethyl acrylate)] (P[(VA)-r-(VBrP)-g-(HEA)]), a water soluble polymer. When unpurified HEA monomer was polymerised, a cross-linked material was recovered with a 50% swelling ratio. N-isopropylacrylamide was also polymerised using P[(VA)-r-(VBrP)] macroinitiator containing 62% initiating sites, to synthesise a thermoresponsive polymer with a lower critical saturation temperature of 36 oC.
Chapter 8 surmises and concludes the work covered in Chapters 2 - 7, and further work is also suggested.