Biomaterial Database

Oligo(lactic acid)-grafted starch: A compatibilizer for poly(lactic acid)/thermoplastic starch blend. 2020

Narumol Noivoil, and Rangrong Yoksan

Department of Packaging and Materials Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand; Center for Advanced Studies for Agriculture and Food, Kasetsart University Institute for Advanced Studies, Kasetsart University, Bangkok 10900, Thailand.

The objective of this study was to improve the compatibility between poly(lactic acid) (PLA) and thermoplastic starch (TPS) in PLA/TPS blown films by incorporating oligo(lactic acid)-grafted starch (OLA-g-starch) as a compatibilizer. OLA-g-starch with a degree of substitution of 1.2 and degree of polymerization of 2.0 was synthesized via a ring-opening polymerization of lactide initiated by hydroxyl groups of starch. The PLA/TPS blends containing OLA-g-starch were prepared using a twin-screw extruder with a constant weight proportion of PLA to TPS of 50:50 and various concentrations of OLA-g-starch, i.e., 1, 2, 3, and 5%. The obtained blends were blown into thin films using a blown film extruder. SEM confirmed the droplet/matrix morphology of the PLA/TPS blends both with and without OLA-g-starch. Incorporating OLA-g-starch improved the compatibility between the TPS dispersed phase and PLA matrix, as evidenced by the smaller size and better distribution of the TPS phase. As a result, the blends containing OLA-g-starch exhibited up to 280% greater extensibility as well as enhanced water vapor and oxygen barrier properties, water resistance, melt flowability, and thermal stability. The Tg, Tcc, and Tm of PLA in the blends shifted to higher temperatures when OLA-g-starch was incorporated. The obtained PLA/TPS blown film containing OLA-g-starch has the potential to be used as flexible packaging.

UI	MeSH Term	Description	Entries
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D010969	Plastics	Polymeric materials (usually organic) of large molecular weight which can be shaped by flow. Plastic usually refers to the final product with fillers, plasticizers, pigments, and stabilizers included (versus the resin, the homogeneous polymeric starting material). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Plastic
D011091	Polyesters	Polymers of organic acids and alcohols, with ester linkages--usually polyethylene terephthalate; can be cured into hard plastic, films or tapes, or fibers which can be woven into fabrics, meshes or velours.	Polyester
D013213	Starch	Any of a group of polysaccharides of the general formula (C6-H10-O5)n, composed of a long-chain polymer of glucose in the form of amylose and amylopectin. It is the chief storage form of energy reserve (carbohydrates) in plants.	Amylomaize Starch,Amylum,Cornstarch,Keoflo,Starch, Amylomaize
D013227	Steam	Water in its gaseous state. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Water Vapor,Steams,Vapor, Water,Vapors, Water,Water Vapors
D013696	Temperature	The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.	Temperatures