Polystyrene With Trifluoromethyl Units: Monomer Reactivity Ratios, Thermal Behavior, Flammability, And Thermal Degradation Kinetics

Chemical modification based on incorporation of flame retardants (FR) into the polymer backbone was used in order to reduce polystyrene flammability. 3-(trifluoromethyl) styrene (StCF(3)) and 3,5-bis(trifluoromethyl) styrene (St(CF3)(2)) were applied as reactive FR. Copolymers were synthesized with different feed ratios and it gave series of copolymers with various amounts of StCF(3) and St(CF3) 2 (5-50% mol/mol of St). Glass transition temperature (T-g) and thermal stability of obtained (co) polymers were determined from differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. Kinetic parameters such as the thermal decomposition activation energy (E) and frequency factor (A) were estimated by Ozawa and Kissinger models. Pyrolysis combustion flow calorimeter (PCFC) was applied as a tool for assessing the flammability of the synthesized (co) polymers. Relative reactivity ratios were determined by applying the conventional linearization Jaacks method (r(St) = 1.34, r(StCF3) = 0.54), (r(St) = 0.47, r(St(CF3)2) = 0.13). The results suggest that incorporation of fluorinated styrenes into PSt enchance flame retardance. (C) 2015 Wiley Periodicals, Inc.