Preparation and characterization of the ethylene‐vinyl acetate copolymer partially hydrolyzed assisted by microwave radiation

Abstract

Ethylene-vinyl acetate copolymer (EVA) was modified by hydrolysis using dielectric heating. The modified EVA was characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis (TG), 1 H Nuclear magnetic resonance (NMR), gel permeation chromatography, and small-angle X-ray scattering. The results showed that the EVA was hydrolyzed with degree between 36.1 and 42.6% according to 1 H NMR and TG results. The relative reaction rate for the sample prepared in the oil bath was 9%/h, while in the dielectric was 150%/h for 15 min. This significant improvement was due to the specific effect of microwave-assisted reactions through dipole rotation and ionic polarization contributions. The hydrolysis reaction promoted a reduction of the pendent group size of EVA backbone. This change directly contributed to increasing melt temperature, crystallization temperature, melt and crystallization enthalpies. Also, decreased the long period, increased the volume crystallinity, and caused reductions amorphous/ crystalline interface and two-phase model deviations.

Synthesis, properties and thermal stability of water‐soluble poly(potassium 1‐hydroxyacrylate‐co‐styrene) copolymer

“…The proton signal area of four methylene hydrogens was assigned in the region 1.8 − 2.4 ppm and 1.3− 1.45 ppm, resulting in I 1.8 − 2.4ppm and 1.3− 1.45ppm = 2MD + 2St. The monomeric part incorporated in the copolymer was estimated by the integrated signal area of the c proton divided by the four methylene proton signal area of a, b protons in the copolymer spectrum . The copolymer compositions of poly(MD‐ co ‐St) copolymer at different molar ratios can be expressed by …”

“…A minor degradation took place between 460 and 668 °C which exhibited the 18.4% weight loss due to the main chain degradation of the copolymer. The MD weight percentage in the copolymer was calculated using …”

“…The monomeric part incorporated in the copolymer was estimated by the integrated signal area of the c proton divided by the four methylene proton signal area of a, b protons in the copolymer spectrum. 31 The copolymer 114 www.soci.org B Kumar, YS Negi compositions of poly(MD-co-St) copolymer at different molar ratios can be expressed by…”

“…× 100 (4) The weight percentages of styrene, methylene dioxolanone and PKHA were calculated by TGA analysis according to the previously described method. 31 First, we determined the MD content in the poly(MD-co-St) copolymer at different molar ratios because at the first mass loss in the TGA curve the MD becomes carbon dioxide and isobutyraldehyde. The poly(MD-co-St) copolymer exhibited a three-step degradation process, as shown in Fig.…”

Inactivation of Pseudomonas aeruginosa in mineral water by DP1 bacteriophage immobilized on ethylene‐vinyl acetate copolymer used as seal caps of plastic bottles

“…However, EVOH or EVA-OH has the most promising gas-barrier properties due to better chain packing aided by hydrogen bonds. [25,26] The objective of the present study was to immobilize DP1 phages on the surfaces of EVA used as seal caps of plastic bottles for mineral water. We also investigated the samples of EVA and EVA-OH produced by microwaveassisted alcoholysis, aiming to understand how chemical interaction occurs between the polymer groups and phages and its capacity to eliminate P. aeruginosa in mineral water.…”