Miscibility of Ternary Amorphous Nylon/Poly(methyl methacrylate)/Poly(4-vinylphenol) Blends

Abstract

The misciblity of ternary blends consisting of amorphous nylon (Am-Nylon)/poly(methyl methacrylate) (PMMA)/poly(4-vinylphenol) (PVPh) at 190°C was investigated by differential scanning calorimetry (DSC),thermo-photometry, Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). In the ternary blends, more than 70—90 wt% PVPh was required to cause miscibility between Am-Nylon and PMMA, and the experimental ternary diagram indicating symmetrically miscible regions was obtained. FT-IR results showed this miscibility was attributed to intermolecular hydrogen bonding interactions. Using stoichiometric equations, the equilibrium constant (Kc=3.2) describing hydrogen bonding between the OH group of PVPh and amide group of Am-Nylon was determined from quantitative FT-IR analysis. The miscible region was affected by individual equilibrium constants (Ki), since individual binary interaction parameters (χij) were significantly larger than the critical value of χij. The miscibility of Am-Nylon/PMMA blends was enhanced by adding 20 wt% PVPh to binary immiscible polymer. The size of the dispersed PMMA phase was thus smaller than in the absence of PVPh. This suggests that PVPh acts as a compatibilizer for immiscible Am-Nylon / PMMA blends.