مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

Based on our previous results of a good agreement between Monte Carlo simulation and DSC measurement for amide interchange reactions (AIRs) during PA6/PA66 melt blending processes, an improved Monte Carlo model comprising AIRs, polycondensation, and hydrolysis was established to illustrate the kinetic scheme of randomization for PA6/PA66 blending systems. Validity of the improved Monte Carlo model which transformed the macro-scale rate constant into a micro-scale rate constant in the simulation was testified by experiments. The effect of blending temperature on AIRs and the influence of AIRs on degree of transamidation, randomness, regularity, and numberaverage block length of various sequences were analyzed in detail with the improved Monte Carlo model describing a kinetic process through a pseudorandom number. One-order exponential decay (Exp-decay 1) technique was employed to correlate melting points of copolyamides measured by differential scanning calorimeter (DSC) with degree of regularity simulated theoretically with the improved Monte Carlo model. First, the model established direct relationship between the mathematical simulation and the experiments then, it was applied to other polyamide blending systems after minor alteration of reaction parameter. It was found that degree of randomness and regularity are independent of blend molar ratio while melting point, molar fractions of amido linkages and number-average block length are blend molar ratio dependent.