SYNTHESIS AND CHARACTERIZATION OF POLY(DIMETHYLBUTADIENE) COPOLYMERS

2,3-dimethyl-1,3-butadiene (DMB), typically referred to as dimethylbutadiene has been used to prepare a variety of homopolymers and copolymers by living anionic polymerization. The effect of different reaction parameters such as polarity of the solvent, temperature or initial concentration of initiator on the microstructure of poly(dimethylbutadiene) (PDMB) has been investigated. The synthesis of a series of statistical copolymers, in benzene and n-heptane, of DMB with butadiene, styrene and 1,1-diphenylethylene (DPE) has been carried out with the goal of understanding the copolymerization behaviour. The reactivity ratios of each pair DMB/comonomer has been calculated. The synthesis of randomly branched polymers of DMB via anionic chain transfer polymerization using divinylbenzene (DVB) as branching agent and potassium tert-butoxide as chain transfer promoter has been investigated. Different mole fractions of both DMB and DVB has been tested in order to balance the extent of crosslinking and chain-transfer with the aim of inhibiting crosslinking and producing soluble branched copolymer. The homopolymers and copolymers has been analysed by a variety of techniques including 1H-NMR spectroscopy, Differential Scanning Calorimetry (DSC) and Size Exclusion Chromatography (SEC).