Study of the Degradation of Biobased Plastic after Stress Tests in Water

Abstract

Research on compostable bioplastics has recently obtained performances comparable to traditional plastics, like water vapor permeability, sealability, and UV transmission. Therefore, it is crucial to create new tools that help the developers of new polymeric composites study them quickly and cost-effectively. In this work, Raman spectroscopy (RS) was proposed as a versatile tool to investigate the degradation of biobased plastics after a stress test in water: this approach is a novelty for food packaging. Treatments at room temperature (RT) and 80 °C were selected, considering that these biopolymers can be used to packaging ready meals. The investigation was carried out on single-layer sheets of poly-lactic acid (PLA), cellulose ester (CE), poly-butylene succinate (PBS), poly-butylene adipate-co-terephthalate (PBAT), and a new composite material obtained by coupling CE and PBS (BB951) and PLA and CE (BB961). The vibrational modes of the water-treated materials at RT and 80 °C were compared to the Raman spectra of the pristine bioplastic, and the morphologies of the polymers were analyzed by scanning electron microscopy (SEM) and optical microscopy. Composite sheets were the plastics which were mostly affected by the 80 °C treatment in water, through changes in morphology (wrinkling with alternate white and transparent zones), as was especially the case for BB951. The Raman spectra acquired in different zones showed that the vibrations of BB951 were generally maintained in transparent zones but reduced or lacking in white zones. At the same time, the single-layer materials were almost unchanged. For BB961, the Raman vibrations were only slightly modified, in agreement with the visual inspection. The results suggest that RS detects the specific chemical bond that was modified, helping us understand the degradation process of biobased plastics after water treatment.

Sequential Infiltration Synthesis of Al2O3 in Biodegradable Polybutylene Succinate: Characterization of the Infiltration Mechanism

“…All the spectra were normalized to the peak of asymmetric −CH bending at 1468 cm –1 which is indicated by a * in Figure , because the C–H group is not directly involved in the infiltration process. The band assignments are in perfect agreement with the literature data. , The comparison between the spectrum of the pristine PBS matrix and those of the infiltrated PBS samples highlights that infiltration of PBS with TMA and H 2 O precursors did not cause the formation of new peaks that can be directly associated with alumina phases, irrespective of the TMA pulse time. According to the literature, Raman signals are expected to appear at 1180 and 1247 cm –1 for θ-Al 2 O 3 and at 1375 and 1405 cm –1 α-Al 2 O 3 . , Actually, no peaks are present in the spectra at these specific wavelengths.…”

“…The band assignments are in perfect agreement with the literature data. 30,31 The comparison between the spectrum of the pristine PBS matrix and those of the infiltrated PBS samples highlights that infiltration of PBS with TMA and H 2 O precursors did not cause the formation of new peaks that can be directly associated with alumina phases, irrespective of the TMA pulse time. According to the literature, Raman signals are expected to appear at 1180 and 1247 cm −1 for θ-Al 2 O 3 and at 1375 and 1405 cm −1 α-Al 2 O 3 .…”

Biodegradable biopolymers for active packaging: demand, development and directions

“…102 Furthermore, Raman spectroscopy may be used to detect modification of chemical bonds and relate this to biodegradation rates. 103 It is worth noting that weight loss of the material may be considered a secondary parameter, and CO 2 evolution is preferable to determine biodegradation rates. 36 Importantly, the tests must be carried out on the final form of the material, including any active agents or other additives.…”

Advances in Bio-Based and Biodegradable Polymeric Composites

“…For instance, in vitro degradation of commercial PGA-based sutures (Dexon ® ) approved by the FDA in 1969 resulted in a 42% decrease in polymer weight and loss of mechanical properties in 28 days [86]. PLGA and PLA are considered as polymers with moderate degradation rates while PCL and PBS are slowly degradable aliphatic polyesters [80,90,258]. In vitro experiments in various media (composting, burial in soil, seawater, presence of lipase enzyme or activated sludge) demonstrated that PBS biodegradation was significantly lower than for PCL and PHBV but higher than for petrochemical plastics [91].…”