Effect of solvent on the microstructure of polyvinyl alcohol

Abstract

The method for producing polyvinyl alcohol (PVA) by the solution polymerization of vinyl acetate first and then alcoholysis strategy is industrial. Where solvent plays a vital role in control over stereoregularity, molecular weight and its distribution, crystallinity and so on. In this report, when methyl acetate was used as a solvent in the polymerization of vinyl acetate instead of methanol, prepared PVA was characterized by Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed that PVA obtained in methyl acetate has a higher content of syndiotactic structure, crystallinity melting temperature and enhanced thermal stability compared with PVA obtained in methanol due to the formation of Π -Π complex between methyl acetate and vinyl acetate and the enhanced steric hindrance effect during polymerization. Additionally, methyl acetate has a smaller chain transfer constant (1.31 Â 10 À4 ), which benefits to decrease the branching degree and molecular weight distribution index of PVA. This research provides more ideas for the choice of solvents in the industrial production of polyvinyl alcohol.

Preparation and Study of Polyvinyl Alcohol Gel Structures with Acrylamide and 2-Acrylamido-2-methyl-1-propanesulfonic Acid for Application in Saline Oil Reservoirs for Profile Modification

“…This means that saltwater enhances the rigidity of the polymer backbone, and the spatial network structure of the gel is more compact. The comparison of the T g of PVA, AM, and AMPS polymers − showed that the T g of polymer gel changed, indicating the miscibility of the polymeric structures. The sharp endothermic peak at 203.83 °C for the gel sample prepared with DI corresponded to the melting.…”

New strategies for surface modification of poly (vinyl alcohol) toward click chemistry applications

“…Due to its capacity to undergo pyrolysis at high temperatures, PVA has a melting point of roughly 230 C, hydrolyzes between 180-190 C, and quickly decomposes over 200 C. [16][17][18] Organic coatings, polymeric component, flexible electronics, biomedical devices, and medical technology are just a few of the applications that rely on functional polymer surfaces produced in cutting-edge scientific and technological fields. [19][20][21] Surface modification of polymers can be utilized to improve biological resistance, compatibility or degradability, impact response, thermal stability, multiphase physical response, flexibility, stiffness, and other properties. [22][23][24] According to the literature, the most common PVA modification processes involving hydroxyl groups are esterification, etherification, and acetalization.…”