Thermal Analysis of Plastics Used in the Food Industry

Abstract

Fires in landfills, where used plastic packaging waste is discarded, have shown how great a fire hazard these types of materials pose. In this study, the course of thermo-oxidation of samples made of polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) based plastics was determined. Based on an analysis of the dissociation energy of bonds between atoms in a polymer molecule, the mechanisms responsible for the character and course of degradation were observed. It was found that the degradation rate of PP and PS could be a result of the stability of C-H bonds on the tertiary carbon atom. In the case of PS, due to facilitated intramolecular hydrogen transfer, stabilization of hydroperoxide, and formation of a stable tertiary alcohol molecule, the onset of degradation is shifted towards higher temperatures than in the case of PP. Notably, the PP fragmentation occurs to a greater extent due to the easier course of β-scission. In addition, it was found that during a fire, the least amount of heat would be generated by thermo-oxidation of PS-based plastics. This is a result of the formation of a styrene molecule during decomposition that, due to the high stability of bonds in the aromatic ring, escapes from the combustion zone without oxidation. It has been proven that the greatest thermal effect accompanies PET decomposition, during which a phenyl radical is produced, where the C-H bonds break more easily in comparison with the bonds of an intact ring.

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“…Explore ways to delay aging and eliminate static electricity. Majder-Lopatka et al, 2022 Polyvinyl chloride plastic 1. It has good transparency, thermal stability and dyeability.…”

Synthesis and Properties of Fully Biobased Crosslinked Starch Oleate Films

“…Although crosslinking did not increase T d further, this might not be a problem since common plastics in the packaging industry, e.g., polypropylene, have a comparable T d . Thus, an increase in T d is therefore not essential for application purposes [40].…”

Material Characterizations of the Polymers Reinforced with Recycled Flexible Plastic Blends as Filament for 3D Printing

“…The contaminants or dust that occasionally make their way into mixtures while manufacturing flexible plastics could be the cause [28]. The variations in weight loss and decomposition rates proved that additional substances impacted plastic decomposition was agreed by Majder-Lopatka et al, [29]. Whereas the degree of branching, the presence of impurities, the size of the particles, or the sample's thermal history have additional factors that could have impacted the values as was reported by Yew et al, [30].…”

“…Whereas the degree of branching, the presence of impurities, the size of the particles, or the sample's thermal history have additional factors that could have impacted the values as was reported by Yew et al, [30]. Plasticizers, antioxidants, lubricants, colours, light, heat stabilizers, and thermos-stabilizers were the most used additives that affect a material's properties [29]. From another point of view, the different additions of RF percentage do not significantly affect the polymer blends.…”