Determinación de la influencia del tamaño de partícula en la hidrólisis alcalina del polietilentereftalato (PET) post consumo

Abstract

The objective of this study was to identify the effect caused by the size of the plastic pellet on the percentage of yield obtained from alkaline hydrolysis. The plastic sample was polyethylene terephthalate sampled within the ESPOCH facilities. The two-particle sizes used were 10mm and 5mm, in addition to this, two types of plastic colours were also used, pink and green. Alkaline hydrolysis was developed on a laboratory scale with commonly used materials. The chemical recycling conditions were T ° 120 ° C, 5g of plastic, 5g of sodium hydroxide, 20mL of water and 20mL of ethylene glycol for 30 minutes with constant stirring, as a final product a fine whitish powder was obtained. To characterize the monomer, the infrared spectroscopy technique and solubility test were used, thus corroborating the properties of terephthalic acid. The best average percentage of depolymerization was 96.11%. It was obtained with plastic colour (green) and particle size (5mm), for the lowest percentage referring to an average percentage of 85.89% was obtained using the 10mm diameter pink plastic. The justification for the selection of these conditions is based on the fact that the smaller the pellet, the greater the possibility of the base interacting with the Polyethylene Terephthalate (PET) molecules. On the other hand, the pigment detected in both colours corresponds to the quinacridone and phthalocyanine families, both aromatic compounds have electrophilic carbons that prevent the direct attack of the base towards the PET molecules, thus causing a lower yield. It is recommended to continue with future research related to plastic recycling involving new conditions.