Inorganic-Organic Hybrid Materials Based on Amino Acid Modified Hydrotalcites Used as UV-Absorber Fillers for Polybutylene Succinate
Résumé
Polybutylene succinate (PBS)-functionalized nanocomposites with amino acid tyrosine (TYR)- and tryptophan (TRY)-hybrid-interleaved layered double hydroxide (LDH) materials exhibit interesting anti-UV properties and rheological properties. Embedding amino acid into the layered double hydroxide container preserves the UV shielding property of the pristine organic molecule. When employed in an aliphatic polymer such as PBS, chain scission occurs during photoageing and accelerates the degradation of the raw material. However the embedded inorganic amino acid melt blended with PBS prevents such degradative phenomenon. An investigation of their structure-property relationship (i.e., nonmiscibility and expanded PBS nanocomposite structures) was conducted. The nonmiscible structure observed for LDHTYR was found to be associated with a chain-extender behaviour, whereas the interleaved structure of PBS-LDH-TRY yielded a liquid-gel transition. Both PBS nanocomposite structures were found to be stable under agressive UV conditions, whereas amino acid free of an LDH container resulted in a deleterious effect when dispersed in PBS, largely promoting PBS chain scission. Hence amino acid organically modified hydrotalcites appear to hold promise for use as UV absorbers when dispersed into other aliphatic biodegradable polymers.