Degradation study of polypropylene (PP) and bioriented polypropylene (BOPP) in the environment

Carina Longo,Michele Savaris,Ana Maria Coulon Grisa,Rosmary Nichele Brandalise,Mára Zeni

doi:10.1590/s1516-14392011005000080

Carina Longo, Michele Savaris + Show 3 more

Open Access

https://doi.org/10.1590/s1516-14392011005000080

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Journal: Materials Research	Publication Date: Nov 1, 2011
Citations: 93	License type: cc-by

Affiliation: Universidade de Caxias do Sul

Abstract

Polymers are vastly employed for numerous purposes in different industrial segments and generate soaring quantities of discarding in the environment. This research analyzed the degradability/biodegradability of polypropylene films (PP) and Bioriented polypropylene (BOPP) polymers after 11 months interred in the Sao Giacomo landfill in Caxias do Sul. Comparing the buried PP film to a sample of virgin PP, two peaks of degrading activity appeared at the TG curve as well as structure modification typified by occurrence of new absorption bands at FTIR, which can be credited to changes in crystallinity. Thermal analysis carried out on the buried PP and BOPP showed decreases in the percentage of crystallinity due to chain scission. The major reduction was observed in the PP, since its crystallinity is a consequence of polymerization instead of chain orientation processes, as in BOPP. Cracks and erosion of the polymer surface were detected in both PP and BOPP, indicating degrading processes by microorganisms.

Highlights

Amongst the various components of waste in landfills, polymeric materials composites account for an estimated 20 to 30% of the total volume of solid waste disposed
The inflection point on the TG curve for the waste polypropylene films (PP) was found to be 454 °C, similar to the results found in this study
Thermal analysis on PP and Bioriented Polypropylene (BOPP) buried polymers showed reduction in the percentage of crystallinity, and this occurrence was credited to chain scission

Summary

Introduction

Amongst the various components of waste in landfills, polymeric materials composites account for an estimated 20 to 30% of the total volume of solid waste disposed. Since polymeric materials are immune to microbial degrading, they remain in the soil and in landfills as a semi-permanent residue. One of the most challenging classes of waste to dispose of, in such a degree that its discarding is being blamed for shortening the life span of a sanitary landfill[1]. The total mass of solid waste from the selective waste collection in the town of Caxias do Sul – RS, was of 17.3% in 2003 (ZATTERA et al, 2007), while the quantities concerning the percentage of polymeric post-consumption discards rigid PP packaging accounted for an average of 7.46%[2]. As the use of the material widens so does the amount of waste disposed of into the environment[3,4]

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