Molecular Modeling on the Binary Blend Compatibility of Poly(vinyl alcohol) and Poly(methyl methacrylate):  An Atomistic Simulation and Thermodynamic Approach

Abstract

Computer simulations play an important role in designing new polymers as well as in predicting properties of existing polymers. In this paper, the blend compatibility of poly(vinyl alcohol) (PVA) with poly(methyl methacrylate) (PMMA) was studied over the wide range of compositions allowed by the atomistic and mesoscopic simulation methods. The Flory-Huggins interaction parameter, chi, of the blends computed using the atomistic simulation confirmed the blend compatibility for compositions containing >60 wt % of PVA. This observation was further supported by differential scanning calorimetric experiments. Solubility parameters of the polymers obtained from the simulation procedure were in good agreement with those of the literature data. Simulation results were further supported by the spectral and solution property measurements. From the atomistic simulations, chi versus concentration plots were constructed, which showed trends similar to those experimentally measured melting temperature versus concentration. The chi values for the blends, which satisfied the criteria of miscibility of two polymers by the atomistic simulation, agreed quite well with the solubility criteria related to order parameters calculated from the mesoscopic simulation. Kinetics of phase separation was examined via density profiles calculated using the MesoDyn approach for incompatible blends. The length and time scales spanned by these simulations were found to be relevant to the real application scales. The free energy computed in the mesoscopic simulation for blends reached equilibrium, particularly when the simulation was performed at a higher time step, indicating the stability of the blend system at certain compositions.

Dynamic Viscosity of PEG:PEG‐ran‐PPG Blends through Stress Relaxation

“…As the periodic boundary conditions [35] are applied on the center-of-mass of the chains, a few monomers of both types of chains are seen to hang out of the edges of the cube. The snapshots in Figure 4 are in principle similar to those shown for PVA:PMMA blends, [12] PVA:PLL blends [14] and PEO:PVC blends. [18] A typical relaxation modulus curve (i.e., stress tensor time correlation function) has been shown in Figure 5 along with empirical fits of the two groups of data points.…”

“…A critical value of x may be estimated from the degrees of polymerization m 1 and m 2 (actual number of repeating units) of the two components. [12] x critical ¼ 1 2…”

“…[poly(isobutylene):poly(propylene)], [11] PVA:PMMA [poly (vinyl alcohol):poly(methyl methacrylate)], [12] PEB:PEP…”

Prediction of Hildebrand solubility parameters of acrylate and methacrylate monomers and their mixtures by molecular simulation

“…Particle-based simulations with accurate force fields offer a promising alternative. This strategy has been pursued with success by Belmares et al, 15 Aminabhavi and co-workers [16][17][18] and this research group 19,20 for a large set of diverse small molecules (solvents and monomers) and polymers with known solubility parameter values. The current work extends previous work into an area where solubility parameter data are scarce: the n-alkyl acrylate and methacrylate monomer series, together with other esters of branched chain and polar functionalities.…”

Analysis of the Miscibility of Polymer Blends Through Molecular Dynamics Simulations

“…For larger values of , the components are completely immiscible. By comparison of the values of  calculated by atomistic simulation with the critical value (equation 8) the miscibility behaviour of the system can be predicted (Jawalkar S.S. et al, 2005).…”