Association between plasticized starch and polyesters: Processing and performances of injected biodegradable systems

• Published in: Polymer engineering and science Vol. 41; no. 5; pp. 727 - 734
• Main Authors: Avérous, Luc, Fringant, Christophe
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.05.2001; Wiley Subscription Services; Society of Plastics Engineers, Inc; Blackwell Publishing Ltd
• Subjects: Applied sciences; Biodegradation; Environmental aspects; Exact sciences and technology; Mechanical properties; Organic polymers; Physicochemistry of polymers; Plastics; Plastics industry; Polyester fibers; Properties and characterization; Thermoplastic composites; Wheat products; United States; Polymer blends; Property composition relationship; Starch; Impact strength; Ester polymer; Water content; Mechanical properties; Injection molding; Oside polymer; Tensile property; Shrinkage; Experimental study
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.10768

Different formulations of wheat thermoplastic starch (TPS) have been processed with various plasticizer/starch ratios and moisture contents. The biodegradable polyesters tested are polycaprolactone (PCL), polyester amide (PEA), polybutylene succinate adipate (PBSA) and polybutylene adipate co terephtalate (PBAT). TPS and polyesters are melt blended in different proportions by extrusion and then injected to obtain dumbbell specimens. Various properties are evaluated such as the mechanical properties (tensile and impact tests), and the hydrophilic character with contact angle measurements. Additionally, uniaxial shrinkage is evaluated. Results show that the addition of polyester to TPS increases the dimensional post‐injection stability. Blend modulus values are close to the results of the classical rule of mixture. Elongation at break, resilience values and SEM observations seem to give some indications about the compatibility between both polymeric systems. PBAT and PEA present better results than PCL and PBSA. Contact angle measurement show that we have a drastic increase of the hydrophobic character from 10% of polyester in the blend. The different combinations of TPS and polyesters give a wide range of mechanical behavior for compostable materials, to be developed in specific applications.