Abiotic and biotic degradations of a LDPE blend in soil of South Brazil landfill

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ORIGINAL RESEARCH

Abiotic and biotic degradations of a LDPE blend in soil of South Brazil landfill Gabriela Miranda1 · Jéssica Pires1 · Gabriela Souza2 · Flávia Fraga2 · Carla Azevedo2 · Rogério Lourega1,2 · Jeane Lima1,2   · Rosane Ligabue1,2 Received: 16 March 2020 / Accepted: 9 September 2020 © Iran Polymer and Petrochemical Institute 2020

Abstract Polyethylene degrades slowly when discarded in the environment and exposed to natural weathering. A solution to this problem is the incorporation of additives to accelerate its biodegradation. In the present study, a biodegradable low-density polyethylene (LDPE) blend was obtained by the mixture of LDPE with a biodegrading additive (8% w/w) and the effect of accelerated weathering on biodegradation process was assessed. Chemical, mechanical, thermal, and morphological properties of non-aged and aged samples were studied. Results showed that aging process caused changes  on structural characteristics (insertion of functional groups), morphological (appearance of micro-cracks and increased roughness), mechanical (greater stiffness and loss of plasticity) and thermal (lower degree of crystallinity and thermal stability) properties. The presence of biodegrading additive contributed to aging process, since polar functional groups were inserted into additive exposed to soil underwent greater degradation than their non-aged counterparts. C ­ O2 production of aged LDPE blend demonstrated that accelerated weathering influences biodegradation process. In this work, due to availability of O ­ 2 gas, aerobic microorganisms can be the main responsible by the material deterioration, leading to production of microbial biomass, C ­ O2 and ­H2O. Thus, the results of biodegradation (166 days) obtained in this work are promising, once it was reached a natural soil from South Brazil landfill. Keywords  LDPE · Biodegrading additive · Accelerated weathering · Biodeterioration · Biodegradation

Introduction Polyethylene (PE) is one of the most widely used plastics in the world for a variety of several applications, mainly packaging, due to its low cost and excellent properties, including low strength, hardness and rigidity, as well as ductility and impact strength [1, 2]. PE types used commercially were high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ultra-high molar weight polyethylene (UHMWPE), and ultra-low-density polyethylene (ULDPE) [3]. LDPE films are light and easy to use, making them attractive for * Jeane Lima [email protected] 1



Graduate Program in Materials Engineering and Technology, School of Technology, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil



School of Technology, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil

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industrial applications. They are odor-free, non-toxic and show good ductility and low water permeability, allowing their use in food packaging [4, 5]. Their degree of crystallinity influences properties such as tensile and impact stre