The Effect of Accelerated Aging on Polylactide Containing Plant Extracts.

Krzysztof Moraczewski,Rafał Malinowski,Tomasz Karasiewicz,Magdalena Stepczyńska,Bartłomiej Jagodziński,Piotr Rytlewski

doi:10.3390/polym11040575

Abstract

In this study, natural extracts of plant origin were used as anti-aging compounds of biodegradable polymers. Coffee (0.5–10 wt%), cocoa, or cinnamon extracts were added to the polylactide matrix. The obtained materials were subjected to an accelerated aging process (720, 1440, or 2160 h) at 45 °C and 70% relative humidity under continuous UV radiation. The effectiveness of the tested extracts was compared to a commercially available anti-aging compound, 2 wt% of butylated hydroxytoluene. Visual evaluation, scanning electron microscopy, melt flow rate, thermogravimetry, differential scanning calorimetry, tensile strength, and impact tensile tests were performed. We show that the use of smaller amounts of tested extracts is particularly advantageous, which do not adversely affect the properties of polylactide-based materials at low contents. At the same time, their effectiveness in stabilizing tested properties during the accelerated aging process is mostly comparable to or greater than the reference compound.

Highlights

Ageing is a term used in many branches of polymer science and engineering when the properties of the polymer change over a period of time [1]
The destruction process is about the decomposition of polymer chains with the release of low molecular weight chemical compounds that differ from the monomer [5,6,7]
Degradation is the partial decomposition of the polymer, not to low molecular weight products but to fragments with higher molecular weight [8,9,10]

Summary

Introduction

Ageing is a term used in many branches of polymer science and engineering when the properties of the polymer change over a period of time [1] Factors such as thermal, electrical, electrochemical aging, mechanical, environmental exposure, and others have a significant influence on the decrease in polymer material properties during their use. The destruction process is about the decomposition of polymer chains with the release of low molecular weight chemical compounds that differ from the monomer [5,6,7]. It can be caused by physical factors (heat, light radiation, and high energy radiation) or chemical (oxygen, acids, and bases). The factors that initiate degradation can be physical (stresses, heat, and high energy radiation) as well as chemical (oxygen and aggressive media)

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