Johanna Eichelter
University of Vienna, Austria
Title: Biopolymer-Compounds with High-Strength Properties
Biography
Biography: Johanna Eichelter
Abstract
“BigBags”, made of stretched standard polymer tapes (e.g. iPP, PE-HD, PET, and PA), are suitable packaging materials with the required mechanical properties for heavy loads, e.g. fertilizers in agricultural applications. Based on environmental aspects, synthetic highly-stretchable polymer tapes should be replaced by resource-saving Biopolymers to avoid polymer-waste. Until today no Biopolymer-compounds with high-strength properties are known and basic know-how about correlations between stretching parameters and materials properties is very scarce, especially for Biopolymers.
Compounds of starch and Biopolyesters are promising materials for the production of biodegradable products, because of their availability, renewability and biodegradability. However, compared to stretchable films made of synthetic polymers elongations at break of starches are lower by a factor of 100. Plasticizers are used to increase flexibility and stretchability of starch, which is termed “thermoplastic starch” (TPS). The most common plasticizer is glycerol, which reduces the intermolecular bonding forces by increasing the inter(macro)molecular distance.
In this study the influence of different starch pretreatments (e.g. acid degradation) and starch sources (potatoe, maize, …) to the strechability and mechanical properties were investigated. The goal was to develop high-strength TPS-Biopolyester-compounds, which allow for a high stretchability and stiffness as required in BigBag-applications.
Furthermore, correlations between material properties and stretching parameters of Biopolymer-compounds were evaluated. It was found that parameters, such as sample geometry, temperature, degree, as well as velocity of stretching have an influence on mechanical properties. Thick and narrow samples, higher temperatures and lower velocities of stretching result in better mechanical properties. Ultimately, results indicate that the degree of stretching should be lower than 100%.