Bioinspired Thymine Containing Polymers: Synthesis, Characterization and Mathematical Modeling

D. M. MARTINO; D. REYNA; D. A. ESTENOZ; J.C. WARNER

Rio de Janeiro

Congreso; ENPROMER, 2nd Mercosur Congress on Chemical Engineering and 4th Mercosur Congress on Process Systems Engineering; 2005

Biopolymers based on styrene containing thymine are experimental and theoretically investigated. These polymers are similar to polystyrene (PS), with the addition of thymine and charged functional groups. Their structure is similar to the DNA (“bioinspired”) and in the presence of UV light they undergo a dimerization reaction, producing photoresist materials that are environmentally benign and biodegradable.  Copolymers based on vinylbenzylthymine (VBT) and ionically-charged monomers (vinylbenzyl triethylammonium chloride and  vinylphenylsulfonic acid sodium salt) were synthesized to produce water-soluble polymers. The effects of the synthesis conditions (molar ratio between the comonomers, type of comonomers, monomer-to-solvent ratio, temperature of the reaction, residence time, etc.) on the solubility and photoreactivity of the material were studied. Samples were taken along the reactions to determine: monomer conversion and solubility by gravimetric analysis, and molecular weight distribution by Size Exclusion Chromatography (SEC). VBT polymers were used to cast onto a compatible substrate (PET) and then irradiated with UV light at room temperature to produce crosslinking. The cured materials were characterized by Atomic Force Microscopy (AFM), FTIR, UV-vis.  A mathematical model that simulates the biopolymer synthesis was also developed. The model was validated  from experimental data, and allows to predict the evolution of the global reaction variables and the molecular structure of the polymer. The theoretical predictions closely match the experimental measurements.