Reactive compatibilization of polymer blends

This work deals mainly with the role of reaction rate in the reactive compatibilization process of polymer-polymer blending. The polymers contain single terminal functional groups. Reaction kinetics are determined at 180{dollar}spcirc{dollar}C. Reaction rates are also measured with polymethylmethacrylate chains for the last two reactions. The reactions are listed in order of increasing reaction rate. Most of the reactions were performed using 25,000g/mol polymers with some work done at higher molecular weights.; The dependence of the area generation rate on both the reaction rate and the rheological properties of the component polymers are explored in blends where polystyrene is the major phase and the minor phase is either polymethylmethacrylate, polyisoprene, polybutadiene, or polyethylene. When the major phase has a higher viscosity and elasticity than the minor phase, elongated morphologies are seen where there is an enhancement on the rate of reaction. If the reaction is diffusion controlled, this enhanced reaction rate leads to the consumption of all available reactive groups producing large quantities of diblock copolymer. Introduction of polymers containing functional groups at both chain ends leads to the formation of triblock copolymers. The presence of large amounts of diblock and triblock copolymer lead to interesting nanoscale morphologies.; The presence of an interface in the heterogeneous blends appears to enhance the reaction rate of non-diffusion controlled reactions presumably by increasing contact between functional groups at the interface. When shearing an interface containing diblock, all polymers entangled with the diblock are brought (at least briefly) into contact with the interface.; Blends made with polyethylene show large enhancements to the fracture toughness of the polystyrene matrix. Scanning electron microscopy is used to visualize the adhesion between the two polymers at the interface in a fracture surface. It is seen that particles of the matrix polymer can be trapped within minor phase inclusions when a phase inversion occurs.; Blending is performed in a miniature scale cup-and-rotor type mixer. Scanning and transmission electron microscopy are used to analyze the resulting morphologies of heterogeneous blends. Gel permeation chromatography is used to analyze the reaction conversion since all polymers have a narrow polydispersity.