Effect of the storage conditions on mechanical properties and microstructure of biodegradable baked starch foams

Abstract

Starch-based foams (SBFs) were prepared with corn, potato, tapioca, and chayotextle starches. A compression baking process was used to develop the SBFs. Biodegradation studies showed that different sources of starch have a particular behavior. The starches showed values of degradation of 85%, while the degradation of SBFs was~70%. The SBFs were conditioned at relative humidities (RHs) of 0 and 75% and temperatures of 4 and 65°C. The starch source used to prepare the SBFs did not have an effect on the mechanical properties, but the storage conditions showed a significant effect on those properties; an increase of RH causes an increase in the mechanical properties. A similar behavior was observed in the conditioned SBFs at different temperatures. The increase of the storage temperature showed a slight reduction in the values of elongation at break. Microscopy revealed that the conditions of RH and storage temperature affect the internal structure of the SBFs. Efecto de las condiciones de almacenamiento en las propiedades mecánicas y microestructura en espumas biodegradables de almidón cocido RESUMEN El material tipo espuma (MTE) fue preparado con almidón de maíz, patata, tapioca y chayotextle. Se utilizó un proceso de termo-compresión para elaborar el MTF. Los estudios de biodegradación mostraron que las diferentes fuentes de almidón tienen un particular comportamiento. Los almidones mostraron valores de degradación de~85%, mientras que en el MTF fue de~70%. Los MTF fueron acondicionados a humedades relativas (HR) de 0 y 75% y a temperaturas de 4 y 65°C. Las fuentes de almidones utilizados para preparar el MTF no afectaron a las propiedades mecánicas, pero las condiciones mostraron un significante efecto sobre estas propiedades; un incremento de la HR causa un incremento en las propiedades mecánicas. Similar comportamiento fue observado en el MTF acondicionado a diferentes temperaturas. El incremento en la temperatura de acondicionamiento mostro una ligera reducción en los valores de elongación a la ruptura. La microscopía reveló que las condiciones de HR y temperatura de almacenamiento afectan a la estructura interna de los MTF.

Biodegradable baked foam made with chayotextle starch mixed with plantain flour and wood fiber

“…However, such materials have turned to be expensive, with low resistance to conditions of high temperature, humidity, and low flexibility . A possible alternative is the use of natural polymers obtained from new sources such as chayotextle starch mixed with plantain flour (PF) . Recent studies have focused on developing satisfactory single‐use foam materials from potato starch, corn starch, cassava starch, tapioca starch, wheat starch, and chayotextle starch .…”

“…A possible alternative is the use of natural polymers obtained from new sources such as chayotextle starch mixed with plantain flour (PF) . Recent studies have focused on developing satisfactory single‐use foam materials from potato starch, corn starch, cassava starch, tapioca starch, wheat starch, and chayotextle starch . Unfortunately, these materials have some drawbacks, such as poor long‐term stability, poor mechanical properties, and a strong affinity for absorbing moisture .…”

“…Baked foam elaborated from starch has the advantage of being biodegradable, inexpensive, and nontoxic. Palma‐Rodríguez et al . reported that foam films elaborated with chayotextle starch have higher values of Eb and a lower elastic modulus compared with foam films made from other raw materials such as corn, potato, and tapioca.…”

Effect of size and amount of sugarcane fibers on the properties of baked foams based on plantain flour

“…Due in part to the large volume of non-biodegradable plastic used globally, researchers are looking for renewable and degradable materials that can replace plastics. This is particularly true in the manufacture of household items such as plates, packaging foams, cups and containers ( Du et al., 2012 ; Palma-Rodríguez et al., 2016 ; Vargas-Torres et al., 2017 ). One of the most biodegradable, inexpensive, and abundant renewable polymer available for use in making containers is starch ( Du et al., 2012 ; Mello and Mali, 2014 ; Palma-Rodríguez et al., 2016 ; Shey et al., 2006 ; Shogren et al., 1998 ).…”

Low Density Wood Particleboards Bonded with Starch Foam—Study of Production Process Conditions

“…On the other hand, starch is known to be self-foamable, which has led to it being proposed as a natural replacement for some synthetic foam applications [9,10,11]. This implies processing via hot mold baking.…”