Dimension stability and thermomechanical characterization of maize starch reinforced with agave salmiana fiber composites

Several species of Agave plants are used for extracting fiber from their leaves. This activity represents an important economic profit for some mestizos and indigenous groups in México. Agave salmiana is mainly used in the production of distilled beverages known as “mezcal” or fermented beverages such as “pulque”. In this work, variety Xa'mni of Agave salmiana fiber, obtained by the traditional technique of manual decorticating young-raw leaves, was used as the reinforcement material of bio-composites made of plasticized maize starch by the extrusion-injection method. The influence of the presence of the fibers affecting thermomechanical properties on the polymeric matrix was evaluated through thermomechanical analysis. From these analysis, it can be observed on one side, that bio-composites made of maize starch plasticized with 20% of glycerol reinforced with 10% of Agave salmiana fibers increases glass transition temperature (Tg) from 94°C to 108°C in penetration mode analysis, indicating a higher thermal resistance to penetration; though, this property diminishes with further addition of fiber content. On the other hand, in macroexpansión test coefficient of thermal expansion (CTE) remains the same in formulations with 10 and 20% fiber content, and it only diminishes when 30% content of fiber is added.