Many biodegradable polymer materials have not been found to be suitable replacements for more traditional non-biodegradable polymers owing to their insufficient gas and vapor barrier properties. The use of a series of novel organically modified synthetic fluorohectorites (FHTs) has been explored to produce biodegradable polybutylene succinate adipate (PBSA)-clay nanocomposites with improved barrier. Highly oriented nanoclay structures (clearly showing a tortuous path required to reduce gas and vapor transmission) were observed using transmission electron microscopy (TEM), resulting in a significant reduction in oxygen permeability (up to a 53% decrease). In particular, these oriented structures were observed in the FHTs modified with di poly(oxyethylene) alkyl methyl ammonium and the longer chain dimethyl dialkyl ammonium. Orientation and dispersion were found to be a result of chemical functionality, chain length, and unique aspect ratios of these FHTs. It was concluded that this reduction in permeability was predominantly due to the tortuous path created by oriented platelets and not from any nucleating effects the platelets may have had. Interestingly, the FHTs were shown to disrupt crystallinity and no change in free volume (as measured using positron annihilation life-time spectroscopy) was observed. The excellent clay dispersion and orientation also led to significant increases in other properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
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