Improvement of active packaging materials based on poly (lactic acid) carrying encapsulated antimicrobial volatiles
MinJung Joo and Eva Almenar
Thesis, Master of Science (Packaging), Michigan State University. 94 pages. 2010.
2010
บทคัดย่อ
Bio-based blends made of poly(lactic acid) (PLA), an aliphatic thermoplastic polyester, and β-cyclodextrins (β-CDs), an enzymatically modified starch, are stiff and brittle due to the incompatibility which limits their applications. The same limitations are expected for bio-based antimicrobial materials created by blending PLA with inclusion complexes (ICs) which serve as a carrier for natural antimicrobial volatile, trans-2-hexenal based on β-CDs. The objective of this study was to overcome limitations by enhancing the compatibility of the carrier with PLS by using a masterbatch. The study was divided into two phases. In phase one, the interfacial adhesion of PLA and β-CDs at various ratios was investigated and the effectiveness of using a masterbatch to improve the adhesion was studied. In phase two, the masterbatch was used to develop an antimicrobial material based on a PLA/ICs blend carrying trans-2-hexenal. The use of the masterbatch significantly enhanced the compatibility between PLA and β-CDs, and improved the thermal, mechanical, optical, and barrier properties of the blends. The antimicrobial PLA/ICs-trans-2-hexenal blend has been shown to be effective against Alternaria Solani. The exposure of the ICs to high heat and relative humidity during processing caused a premature loss of the antimicrobial compound encapsulated in theβ-CD molecules for later release, and resulted in a reduced antimicrobial activity.