Synthesis of novel polymeric materials with potential application in hair care products : combining controlled radical polymerisation and polymer modification

• Main Author: Menzel, Jasmin Patricia
• Format: Dissertation
• Language: English
• Published: University of Warwick 2012
• Subjects: QD Chemistry

It was the original aim of this project to develop new, potentially stimuli sensitive materials with interesting architectures for potential application in hair care products such as shampoos, conditioners or styling products. Furthermore, various methods for the introduction of silicon functionalities into such polymers were investigated. Several methods of controlled radical polymerisation were combined with polymer end group modification to achieve these goals. Initially, polymerisation of several dimethacrylate monomers under catalytic chain transfer (CCT) conditions was optimised with regard to monomer conversion and control of Mw, thus preventing macro-gelation. CCTP is an excellent method for the synthesis of low molecular weight polymers retaining terminal vinyl groups which can be subsequently exploited for end group modification. Polymerising dimethacrylates under these conditions, the formation of highly branched architectures and the retention of a larger number of pendent vinyl groups adds more interesting aspects to synthesised materials. The incorporation of silicon functionalities was attempted in two ways: Via polymerisation of poly(dimethyl siloxane) dimethacrylates and via copolymerisation of a silicon containing monofunctional methacrylate with EGDMA. One of the PDMS dimethacrylates employed for CCTP was synthesed from a silanol terminated PDMS, attempting to introduce hydrolysable functionality and thus yielding potentially hydrolysable, hyperbranched polymers. Michael thiol-ene addition was subsequently used to decorate the pendant vinyl groups in CCTP polymers with a range of thiols, yielding highly functionalised polymers with hyperbranched architecture and low molecular weights. Following up on the idea of developing potentially hydrolysable, silicon containing polymers the synthesis of triblock copolymers with a PDMS middle block was attempted. PDMS dimethacrylates (silanol) were reacted with various thiols, ranging from small functional thiols like benzyl mercaptan or thioglycerol to PEG-thiols obtained via end group modification of mPEGs to aminolysed polymers previously synthesised by RAFT polymerisation. This part of the project was subsequently modified and an alternative approach for the synthesis of PDMS containing amphiphilic di- and triblock copolymers was investigated: Mono- and difunctional PDMS macroinitiators suitable for both ATRP and SET-LRP were synthesised via functionalisation of carbinol terminated PDMS. ATRP and SET-LRP were subsequently compared in the polymerisation of OEGMEMA monomers using these macroinitiators. Thermo-responsitivity of aqueous solutions of the resulting di- and triblock copolymers was studied using turbidimetry and Dynamic Light Scattering. Phase transitions in bulk were characterised by Differential Scanning Calorimetry and thermal stability was investigated via Thermogravimetric Analysis.