Viscoelastic behavior of degradable polyolefins aged in soil

Abstract

Samples of polypropylene and a high density polyethylene/polypropylene blend filled with different biodegradable additives (rice starch/iron oxide mixture, Bioefect 72000 and Mater‐Bi AF05H) have been subjected to an outdoor soil burial test for 21 months. Changes on the morphology of the samples have been studied by differential scanning calorimetry. The degradation process also has been analyzed in terms of the mechanical behavior of the polymers. The three characteristic relaxation zones α, β, and γ (in order of decreasing temperature) of the dynamic‐mechanical relaxation spectra of the samples have been characterized according to the Fuoss–Kirkwood equation. When two relaxations were overlapped, a deconvolution method was applied. It has been observed that the degradation process affects just to a small extent the amorphous phase of the polymers. That the β relaxation is the most sensitive to the exposure time suggests that degradation starts in the crystalline–amorphous interface. However, the crystalline phase is also affected significantly by the degradation process. The mechanical results are in good agreement with the calorimetric measurements, proving that degradation takes place in two stages with different time scales depending on the additive used. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1707–1720, 2000

Thermal characterisation of photo‐oxidized HDPE/Mater‐Bi and LDPE/Mater‐Bi blends buried in soil

“…To assess the potential applications of these blends, their characterization, as well as the study of their degradation process must be performed. As it has already been shown in previous works 14–17. Thermal Analysis can provide useful information about the irreversible changes in the properties of polymers caused by degradation in soil of polymeric materials.…”

Effect of sisal and hydrothermal ageing on the dielectric behaviour of polylactide/sisal biocomposites

“…The effect of hydrothermal ageing on VPLA, as other polymers subjected to other types of degradation [55]- [57], provoked the apparition of small relaxation between the β1 and the αTG relaxations, labelled as VPLA-HT-β2 (Fig 3d). However, after the addition of sisal, this relaxation cannot be detected since it was overlapped by the more prominent β relaxation of sisal [42] in the biocomposites, labelled as PLAX-HT-β2 (Fig 3e-f).…”

Thermal analysis applied to the characterization of degradation in soil of polylactide: I. Calorimetric and viscoelastic analyses

“…Fast, cost-effective and reliable characterization procedures for testing the biodegradation effects on polymers should be developed and implemented. Thermal Analysis techniques have been successfully applied in our research group to monitor and control the degradation effects on the macroscopic properties of polymers submitted to different degradative environments since they offer a huge amount of parameters that can act as indicators of the extent of degradation [22,23,24,25,26]. Figure 1 summarizes the Thermal Analysis techniques proposed for the study of the extent of degradation on PLA: Thermogravimetry (TGA), Differential Scanning Calorimetry (DSC) and Dynamic-Mechanical-Thermal Analysis (DMTA), as well as the principal parameters selected for the study.…”