The Application of (+)-Catechin and Polydatin as Functional Additives for Biodegradable Polyesters

Abstract

Plant polyphenols are a huge group of compounds with a wide spectrum of applications. Substances from this group have been used in polymer materials such as stabilizers, dyes, indicators, fungicides, and bactericides, especially in new generation packaging materials. The aim of this study is to obtain environmentally friendly materials based on the biodegradable aliphatic polyesters, polylactide (PLA) and polyhydroxyalkanoate (PHA), with plant functional additives, (+)-catechin and polydatin. These natural polyphenols (polydatin and (+)-catechin) have not been used so far in polymer materials (especially in biodegradable polyesters) as stabilizers, dyes, and indicators of aging. The application of polydatin and (+)-catechin as multifunctional additives for biodegradable polymers is a scientific novelty. This paper presents the following analyses of polyester materials: SEM microscopy, wide angle x-ray diffraction, mechanical properties, thermal analysis, surface free energy analysis, and determination of change of color after controlled UV exposure, thermal oxidation and weathering. Both PLA and PHA polyesters were characterized by higher resistance to oxidation and greater resistance to degradation under the influence of UV radiation. In addition, (+)-catechin was used simultaneously as a dye and an indicator of the aging time of polymeric materials. In contrast, polydatin did not dye polymers, but was a very good indicator of their lifetime, changing color under the influence of various external factors. Both polyphenols can be successfully used as natural additives for pro-ecological polyesters.

Discharge Plasma Treatment as an Efficient Tool for Improved Poly(lactide) Adhesive–Wood Interactions

“…No changes in surface geometry could be seen at 10 k magnification. Regardless of the PLA film preparation, the surface was compact and smooth, in accordance with the observations of others [29]. However, it should be noted that 60-s modification time was not sufficient to affect surface geometry.…”

Environmentally Friendly Polymer Compositions with Natural Amber Acid

“…The PHA samples being more prone to aging than PLA may be due to the morphology of the materials. Other studies by the authors (SEM analysis) [ 40 , 41 ] showed that PLA had a compact, smooth structure, while the PHA samples were porous. The higher susceptibility of PHA to degradation may be related to its high porosity, i.e., a larger contact surface of the sample with degrading factors and easier oxidation of the material.…”

“…The aging/degradation of PLA is specific and starts with an increase in the crystallinity of the samples, resulting in higher values of the strength properties (T S ). In the next stage of degradation, the crystalline phase content in the samples decreases and the mechanical properties (parameter T s ) decrease [ 40 , 41 ]. The 200 h aging time may be too short for the degradation of the PLA material in which a decrease in the strength is observed.…”

Biopolymers as Food Packaging Materials

“…Latos-Brozio et al [ 10 ] obtained environmentally friendly materials based on the biodegradable aliphatic polyesters (polylactide and polyhydroxyalkanoate) enriched with plant functional additives (catechin and polydatin).…”