Hydrophobically modified poly(vinyl alcohol) and bentonite nanocomposites thereof: Barrier, mechanical, and aesthetic properties

Abstract

Composite films were formed by incorporating three different bentonites into an ethylene modified, water‐soluble poly(vinyl alcohol), EPVOH. The interaction of EPVOH with both hydrophilic and hydrophobic bentonites was investigated. EPVOH provided lower water vapor and oxygen transmission rates compared to a conventional PVOH grade when exposed at high relative humidities (70–90% RH). EPVOH films which exhibited oxygen barrier properties comparable to that of a biaxially oriented PET packaging film at 80% RH were produced. High compatibility between EPVOH and hydrophilic bentonites provided an even distribution of clay platelets in the composites. A strong increase in Young's modulus with increased addition of any of the three bentonites was found. At low addition levels the hydrophobic bentonite proved to be effective in terms of maintaining high elongation at break, high transparency and high gloss. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41737.

Influence of kaolin addition on the dynamics of oxygen mass transport in polyvinyl alcohol dispersion coatings

“…Poly(propylene) (PP) filled with nanoclay displayed an improved barrier performance and the morphology was also affected (Zehetmeyer et al 2012). The same behaviour has been reported for PVOH mixed with nanoclay (Strawhecker, Manias 2000, Yu et al 2003, Johansson, Clegg 2015 and EVOH (Cabedo et al 2004).…”

Effect of clay type on dispersion and barrier properties of hydrophobically modified poly(vinyl alcohol)–bentonite nanocomposites

“…The product contains <3 wt % methanol and <5 wt % volatiles and was used without further purification. The molecular weight, M w , was previously determined to be 61,200 g/mol by size exclusion chromatography and the ethylene content was estimated to be about 8.1 mol % by proton NMR analysis . A standard, unmodified PVOH grade with equal viscosity and degree of hydrolysis and with M w 71,500 g/mol from the same supplier was used as a reference material.…”

“…For instance, the oxygen permeability of PVOH films in general increases 2500 times when going from 0 to 100% RH . The ethylene modification however gives the polymer a hydrophobic character and the films of EPVOH are stated to have lower oxygen transmission rates (OTR) than standard PVOH films by almost an order of magnitude 4 ; they are also more effective barriers at higher relative humidities . These water‐soluble EPVOHs are also claimed to have OTR values below that of commercial EVOH coatings (27 mol % ethylene) in the range from 0 to 70% RH .…”

The influences of silane coupling agents on rheological properties of bentonite/nitrile butadiene rubber nanocomposites during curing process

“…Belonging to the family of clay minerals, bentonite (Bent) has already showed potential as a filler for rubber and other polymers . The reinforcing effects of Bent on the matrixes could be attributed to its nano‐sized layer structure and homogeneous dispersion in polymer matrixes , which apparently improves the mechanical strength, thermal stability, gas barrier properties, etc .…”