Influence of Amphiphilic Plasticizer on Properties of Thermoplastic Starch Films

ABSTRACT

Thermoplastic starch powders and films were produced by using different combinations of hydrophilic (malic acid and water) and amphiphilic (isoleucine and butyric acid) plasticizers. Spray drying was used to produce thermoplastic starch powder followed by compression molding for the development of films. In all plasticized formulations, the rate of retrogradation was inhibited until the seventh day. The crystallinity and moisture sensitivity of the freshly prepared films were dependent on amphiphilic plasticizer quantity in formulation. Fourier transform infrared spectroscopy and thermogravimetric analysis showed an effective interaction of starch with isoleucine. Isoleucine formulated films showed the highest tensile strength, whereas malic acid-rich films showed better strain values.

GRAPHICAL ABSTRACT

KEYWORDS:

• Amphiphilic
• mechanical properties
• plasticizer
• retrogradation
• thermoplastic starch

ABBREVATIONS:

• ATR: attenuated total reflection
• BUPS: butyric acid plasticized
• DTGA: differential thermal gravimetric analysis
• EP: extra pure
• FTIR: Fourier transform infrared spectroscopy
• ISPS: isoleucine plasticized starch
• MAPS: malic acid plasticized starch
• MAISPS: malic acid isoleucine plasticized starch
• MABUPS: malic acid butyric acid plasticized starch
• RH: relative humidity
• RPM: rotations per minute
• SDS: spray-dried starch
• SEM: scanning electron microscopy
• T_g: glass transition temperature
• TGA: thermogravimetric analysis
• TPS: thermoplastic starch
• US: untreated starch
• XRD: X-ray diffraction

Acknowledgments

This study was supported by National University of Sciences and Technology, Islamabad, Pakistan.

Conflict of interest

There is no conflict of interest statement in the manuscript.