Morphological characteristics of stearic acid-grafted starch-compatibilized linear low density polyethylene/thermoplastic starch blown film

Published Date
March 2016, Vol.76:266–277, doi:10.1016/j.eurpolymj.2016.02.001

Title 
Morphological characteristics of stearic acid-grafted starch-compatibilized linear low density polyethylene/thermoplastic starch blown film

• Author 

• Nattaporn Khanoonkon ^a
• Rangrong Yoksan ^a,b,,
• Amod A. Ogale ^c

• aDepartment of Packaging and Materials Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand
• bCenter for Advanced Studies for Agriculture and Food, Kasetsart University, Bangkok 10900, Thailand
• cChemical and Biomolecular Engineering and Center for Advanced Engineering Fibers and Films, Clemson University, Clemson, SC 29634-0909, USA

Received 23 November 2015. Revised 26 January 2016. Accepted 1 February 2016. Available online 1 February 2016.

Highlights

• •
  LLDPE/TPS blend films with a weight ratio of LLDPE:TPS of 60:40 were prepared by blown film extrusion.
• •
  ST-SA with a substitution degree of 0.01 could be used as a compatibilizer for the LLDPE/TPS blend system.
• •
  The blend showed reduced TPS phase size and size distribution in the LLDPE matrix when ST-SA was loaded.
• •
  The optimum compatibilizing effect of the blend was achieved by incorporating 1% of ST-SA.
• •
  ST-SA compatibilizer could interact with TPS via H-bond formation and with LLDPE through hydrophobic interaction.

Abstract

The objective of the present work is to verify the possibility of using stearic acid-grafted starch (ST-SA) as a novel compatibilizer for a blend system consisting of linear low density polyethylene (LLDPE) and thermoplastic starch (TPS). ST-SA was successfully synthesized, as confirmed by FTIR and ¹H NMR techniques. The obtained ST-SA was compounded with LLDPE and TPS in a twin-screw extruder. A weight ratio of LLDPE:TPS was fixed at 60:40, while ST-SA concentrations were varied from 1% to 5%. The blends were further converted into films by blown film extrusion. Incorporation of ST-SA improved the extrusion processability and melt flowability of the LLDPE/TPS blends. In addition, the blends became compatible and homogeneous when ST-SA was loaded due to the increased interfacial adhesion between LLDPE and TPS phases. The results suggest that ST-SA, particularly at a content of 1%, could serve as an effective compatibilizer for the immiscible LLDPE/TPS blend system.

Graphical abstract

Keywords

• Polyethylene
• Thermoplastic starch
• Stearic acid-grafted starch
• Blend
• Morphological characteristics
• Microstructure

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• DOC (1.9M)

Supplementary data 1

• ⁎ 
  Corresponding author at: Department of Packaging and Materials Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok 10900, Thailand.

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