Engineering Starch for High-Value Packaging Film Applications

James Wang, Ph.D.
Research Technical Leader II
Kimberly-Clark Corporation, 2100 Winchester Road, Neenah, WI 54956, U.S.A.


Starch, such as Cassava starch, is an abundant, low-cost feedstock which has been used in a number of relatively low-value industrial applications such as paper sizing materials.  Use of starch for thermoplastic applications is of great business interest to replace petroleum-derived plastic materials which are several times more expensive than starch.  Due to the lack of thermoplasticity of starch, it had to be modified into thermoplastic starch, i.e. TPS.  However, TPS also lacks the required mechanical properties for packaging applications.  In this presentation, a systematic approach was demonstrated to create effective polymer blends to overcome the inherent weakness of pure TPS, the polymer films made from thermoplastic starch and biodegradable modifying polymers were developed.  The films contain multiple bio-based and biodegradable polymer components including thermoplastic starch, bio-based polylactic acid (PLA), a biodegradable aliphatic-aromatic copolyester, and also inorganic mineral component were developed.  Thin biodegradable films were successfully prepared from these polymer blends. 
The relationship between the composition and the film properties will be discussed. 
The films showed significantly improved mechanical properties over those of TPS films for sustainable packaging applications.