Effects of Plasticizing on Mechanical and Viscous Characteristics of Poly(vinyl alcohol): A Comparative Study between Glycerol and Diethanolamine

Abstract

Although plasticizing materials by modification with small‐molecular chemicals has been extensively utilized in the industrial community, processing poly(vinyl alcohol) (PVA) at high concentrations (CPVA) or with a high degree of polymerization (DP) remains challenging. Optimization the plasticizing conditions is one means of addressing this issue. In this study, two types of frequently used plasticizers, glycerol (GLY) and diethanolamine (DEA), are chosen to plasticize PVA resin with a DP of 2400. Both PVA/plasticizer films possess excellent optical transmittance and mechanical ductility, whereas the films blended with DEA exhibit higher strength than the PVA/GLY films. The viscosity variation in the temperature (Top)–CPVA space is monitored by real‐time viscous flow testing, demonstrating that DEA is more effective for reducing the viscosity of PVA, which should improve the processability, facilitating film‐forming from concentrated solutions. Furthermore, density functional theory calculations and molecular dynamics simulations illustrate that the PVA/DEA system has a lower binding energy, longer hydrogen bond length, and higher isotropic diffusion coefficient, indicating a stable hydrogen bond network and homogenous dispersion of the plasticizer, leading to good solution fluidity and mechanical performance. This study is significant for guiding the design and manufacture of optically transparent, high‐performance PVA films as polarizer precursor.

Effects of Plasticizers on Structural Transitions and Heterogeneity of Poly(vinyl alcohol) Films as Studied via AIE Materials

“…The recent work by Gualandi et al suggested a probability that light scattering will change the emission intensity of AIE luminogens during some common conditions like heating/cooling, stretching deformation, and physical aging, accompanied by polymer matrix transparency deterioration. However, the volatilizing PVA solutions as well as ultimately obtained films possessed high optical transparency, i.e., the transmittance within the visible-light range 400–800 nm preserved high as 90%. Such a phenomenon implied that the optical property of the PVA solution did not vary during the film-forming process.…”