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首页> 外文期刊>The Journal of Chemical Physics >Chain length distributions in linear polyaddition proceeding in nano-scale small volumes without mass transfer
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Chain length distributions in linear polyaddition proceeding in nano-scale small volumes without mass transfer

机译：纳米尺度小体积的线性聚成型中的链长分布，无传质

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Computer simulations (Monte Carlo and numerical integration of differential equations) and theoretical analysis show that the statistical nature of polyaddition, both irreversible and reversible one, affects the way the macromolecules of different lengths are distributed among the small volume nano-reactors (droplets in this study) at any reaction time. The corresponding droplet distributions in respect to the number of reacting chains as well as the chain length distributions depend, for the given reaction time, on rate constants of polyaddition k(p) and depolymerization kd (reversible process), and the initial conditions: monomer concentration and the number of its molecules in a droplet. As a model reaction, a simple polyaddition process (M)(1) + (M)(1) reversible arrow (M)(2), (M)(i) + (M)(j) reversible arrow (M)(i+j) was chosen, enabling to observe both kinetic and thermodynamic (apparent equilibrium constant) effects of a small number of reactant molecules in a droplet. The average rate constant of polymerization is lower than in a macroscopic system, depending on the average number of reactant molecules in a droplet. The apparent equilibrium constants of polymerization K-ij = <([(M)(i+j)])over bar> = <(([(M)(i)][(M)(j)]))over bar> appear to depend on oligomer/polymer sizes as well as on the initial number of monomer molecules in a droplet. The corresponding equations, enabling prediction of the equilibrium conditions, were derived. All the analyzed effects are observed not only for ideally dispersed systems, i. e. with all droplets containing initially the same number of monomer (M)(1) molecules, but also when initially the numbers of monomer molecules conform the Poisson distribution, expected for dispersions of reaction mixtures. Published by AIP Publishing.
机译：计算机仿真（微分方程的蒙特卡罗和数值集成）与理论分析表明，聚酰二管道的统计性质，不可逆和可逆的，影响小体积纳米反应器中不同长度的大分子的方式（液滴研究）在任何反应时间。对于给定的反应时间，相应的液滴分布以及链长分布在聚丙烯K（P）和解聚Kd（可逆过程）的速率常数上取决于给定的反应时间，以及初始条件：单体浓度和液滴中分子的数量。作为模型反应，简单的聚酰胺（M）（1）+（M）（1）可逆箭头（M）（2），（M）（I）+（M）（J）可逆箭头（M）（选择了I + J），使少量反应物分子的动力学和热力学（表观平衡常数）效应观察液滴中的动力动力学和热力学（表观平衡常数）效应。聚合的平均速率常数低于宏观系统，取决于液滴中的反应物分子的平均数量。聚合K-IJ = <（[（m）（I + J）]）上的表观平衡常数在酒吧> = <（（（[（m）] [（i）] [（m）] [（j）]））））上方>似乎取决于低聚物/聚合物尺寸以及液滴中的单体分子的初始数量。导出相应的等式，使得能够预测均衡条件。对于理想的分散系统，我认为所有分析的效果都被观察到所有分析的效果。 e。含有初始相同数量的单体（m）（1）分子的所有液滴，而且当最初的单体分子的数量符合泊松分布时，预期的反应混合物的分散量。通过AIP发布发布。

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