A deep insight of solubility behavior, mechanical quantum, thermodynamic, and mechanical properties of Pebax-1657 polymer blends with various types of vinyl polymers: A mechanical quantum and molecular dynamics simulation study

Abstract

Molecular dynamics (MD) simulations are a key method frequently used to develop and design new blend polymers and predict their properties. In this study, frontier molecular orbital (FMO) and mechanical quantum (MQ) methods were used to determine the partial charges, energy values, phase behavior, regioselectivity, chemical reactivity, and surface properties of Pebax-1657 (Px) and three vinyl group polymers. Subsequently, the blend compatibility, miscibility, and mechanical behavior of poly (vinyl fluoride) (PVF), poly (vinyl chloride) (PVC), and poly (vinyl acetate) (PVAc) with Px were analyzed for a range of combinations using atomistic simulation systems. Accordingly, MD simulations were performed for the Px/PVAc, Px/PVC, and Px/PVF blend models with different composition ratios (80/20, 70/30, and 60/40, by weight) at a temperature T = 298 K and pressure P = 1 bar. For all the systems, the electron affinity (A) and ionization energy (I) were determined to calculate the global softness (σ), global hardness (η), polarizability, chemical potential (µ), and electrophilicity index (ω). The softness decreased in the following order: PVC > Px > PVF > PVAc. It can be deduced that PVC and PVAc are the most polarizable and exhibit the lowest chemical reactivities. Additionally, PVF and PVC exhibited the highest and lowest chemical hardness values, respectively. Accordingly, based on the calculated solubility parameters, PVAc, PVC, and PVF were miscible with Px and reached the same glass transition temperature (Tg). Moreover, the χ (chi) parameters of the Px-PVAc, Px-PVC, and Px-PVF polymer blends were ranked as follows: Px-PVF (∼2.66) > Px-PVC (∼1.59) > Px-PVAc (∼0.64), suggesting that Px-PVAc and Px-PVF exhibited high and low miscibility, respectively. Furthermore, the mechanical properties of Px-PVAc, Px-PVC, and Px-PVF blend polymers reduced when the content of PVAc, PVC, and PVF exceeded 30% wt.