Flammability and pyrolysis chemistry of standard and novel fire -safe polymers
Flammability and pyrolysis behavior of standard and novel fire-safe polymers was investigated. Both experimental and modeling techniques were used. Experimental methods included a novel and unique milligram-scale flammability test, Pyrolysis-Combustion Flow Calorimetry (PCFC), as well as thermogravimetric analysis (TGA), differential scanning analysis (DSC), and pyrolysis/gas chromatography-mass spectrometry (Py/GC-MS). Modeling of degradation was performed using a Reactive Molecular Dynamics program called MD_REACT, which allows for bond breaking and bond formation.
Flammability and pyrolysis of novel nanocomposites and copolymers were studied. The effects of various organic and inorganic additives on flammability of standard or novel polymers were analyzed. The positive influence of additives, such as clay, and inorganic comonomers, such as polyhedral oligomeric silsesquioxane (POSS), on flammability parameters was demonstrated. In addition, new intrinsically fire-safe polymers obtained by novel polymerization techniques were presented. These materials included polysiloxane copolymers synthesized via enzymatic catalysis and cyclic-PBT resins polymerized from cyclic-PBT oligomers.
In addition, a complete study of degradation of two standard polymers was performed. Pyrolysis chemistry was investigated for an addition polymer, iso-polypropylene, and a condensation polymer, poly(ethylene adipate). Both the macro- and the microscale were considered in order to relate phenomenological properties to reactions occurring at the molecular scale. First-order reaction kinetics could be applied for mass loss rate for both polymers even though they exhibited very different degradation pathways. Kinetics of mass loss as well as kinetics of elementary reactions were studied. Degradation mechanisms were inferred from experiments at the macroscale and Reactive Molecular Dynamics simulations at the molecular scale.