Background: Polylactic acid (PLA) is growing rapidly in popularity as an alternative to petroleum-derived plastics for packaging and other applications. It is biodegradable thermoplastic and derived from renewable resources. However there are characteristics associated with PLA that limit its workability. Particularly the slow crystallization rate of PLA makes it difficult to process for injection molding and extruding when compared with many other thermoplastics. Nucelating agents are known to increase crystallization rates and in fact many have been explored for use with PLA. However many of the compounds explored as nucleating agents for PLA are not ideal for food contact. Hence there is a need for food-safe nucleating agents that will significantly improve the crystallization rate of PLA. Description: This invention provides a method for using B-cyclodextrins as nucleating agents for PLA. The B-cyclodextrins confer high crystallinity high crystallization rate good clarity and non-coloring to the base polymer. Furthermore the nucleating agents are food-safe and can be incorporated into PLA packaging intended for food applications. The invention also provides a bioplastics formulation which incorporates B-cyclodextrins loaded with plant volatiles possessing antifungal activity (see Technology Listing 06073) to control fungal rot of postharvest fruit. Additionally the nucleating agents can function as a binding agent for ripening agents or other decay inhibitors for fruit. IP Protection Status: Patent pending
(1) Enables improved workability and higher performance of PLA: The B-cyclodextrins have been shown to significantly increase the crystallization rate of the PLA without impacting clarity. Also higher resistance is achieved when using these compounds as nucleating agents. (2) Enables totally biodegradable packaging that is food-safe: Both PLA and B-cyclodextrins are starch-based products that are biodegradable and accepted for use with food. (3) Enables crop lost prevention and prolonged shelf-life of postharvest fruit: While serving as nucleating agents the B-cyclodextrins can be loaded with plant volatiles possessing antifungal activity (see Technology Listing 06073) to control fungal rot of postharvest fruit. Applications: This invention is useful for improving the workability of PLA films intended for food applications. Specifically the invention is useful for enabling a totally biodegradable film capable of extending the shelf-life of postharvest fruit and potentially other foods items.