MATHEMATICAL MODEL OF NITROXIDE-MEDIATED LIVING RADICAL COPOLYMERIZATION IN TUBULAR REACTORS. SECOND PART

ASTEASUAIN, MARIANO; BRANDOLIN, ADRIANA; SARMORIA, CLAUDIA

Los Cocos, Córdoba, Argentina

Simposio; V Argentine-Chilean Polymer Symposium; 2009

PLAPIQUI, INTEMA, INTEC, UNS, UNMDP, UNL, UNC

Copolymers are often characterized in terms of theoverall molecular weight distribution, average molecularweights and average composition. These variables,however, do not consider the copolymer composition ata molecular level. One of the quantities that are relatedto the chain microstructure is the sequence length distribution(SLD). The SLD indicates the lengths of thesequences of each kind of monomer along the copolymerchains. It is well known that product quality can bestrongly dependent on this property in several cases. Forinstance, the SLD may affect the miscibility of differentcopolymers. Large sequences of a monomer in a copolymercan also lead to microphase separation . Moreover, the SLD affects the mechanical properties of microheterogeneous compositesby influencing the material micromorphology. Different approaches have been reported in theliterature for the prediction of the SLD. They are basedon probabilistic methods, Monte Carlo simulations andkinetic modeling . However, thelatter is the least common of the three, in particular forrelatively novel polymerization processes such as theone studied in this work.Living radical, or controlled, polymerization has becomean attractive alternative for synthesizing polymerswith controlled structure. In another work in this Symposium, we presented a mathematical model of a nitroxide-mediated living radical copolymerization in tubular reactors. In that work,the techniques employed for predicting the overall copolymerMWD, average compositions, average molecular weights and monomer conversion as a function of reactor length were explained. On the other hand, this work is focused on describing the methodemployed in the model for computing the copolymerSLD