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|Author(s):||Robert A. Riggleman; K Yoshimoto; Jack F. Douglas; J J. de Pablo;|
|Title:||Tuning the Fragility of Polymer Melts With Antiplasticizer Additives|
|Abstract:||Using molecular dynamics simulations, we have developed and analyzed a model that exhibits antiplasticization behavior by decreasing the glass transition temperature, increasing the density of the system below the glass transition temperature of the pure melt, and increasing the high frequency shear modulus. The addition of antiplasticizing molecules or nanoparticles is shown to make the polymer melt a stronger glass-forming material through the ratios of the chracteristic temperatures, the fragility parameter D from fits of relaxtion time data to the VFTH equation, and through the observation of the temperature dependence of the size of the cooperatively rearranging regions (strings) in each system.The length of the strings of collective motion has a weak temperature dependence in the antiplasticized, stronger glass-forming system compared to the pure polymer, and the strings become increasingly concentrated upon the antiplasticizer moleculaes upon coolling.|
|Citation:||Journal of Chemical Physics|
|Keywords:||antiplasticer additives,biomaterial preservation,film imprinting,fragility,glass transition,nanparticles,polymer melt,shear modulus|