title: Ecotoxicity and fungal deterioration of recycled polypropylene/wood composites: effect of wood content and coupling.
abstract: Recycled polypropylene (rPP) was recovered from an industrial shredder and composites were prepared with a relatively wide range of wood content and with two coupling agents, a maleated PP (MAPP) and a maleated ethylene-propylene-diene elastomer (MAEPDM). The mechanical properties of the composites showed that the coupling agents change structure only slightly, but interfacial adhesion quite drastically. The durability of the materials was determined by exposing them to a range of fungi and, ecotoxicity was studied on the aquatic organism Vibrio fischeri. The composites generally exhibit low acute toxicity, with values below the levels considered to have direct ecotoxic effect on aquatic ecosystems (<2 toxic units). Their toxicity to V. fischeri depended on the presence of the coupling agents with larger E50 values in 24-h aqueous extracts from composites containing MAPP or MAEPDM in comparison to composites without any coupling agent. Evaluation of resistance against fungal colonization and deterioration proved that wood facilitates fungal colonization. Fungi caused slight mass loss (below 3%) but it was not correlated with substantial deterioration in material properties. MAPP seems to be beneficial in the retention of mechanical properties during fungal attack. rPP/wood composites can be considered non-ecotoxic and quite durable, but the influence of wood content on resistance to fungal attack must be taken into account for materials intended for applications requiring long-term outdoor exposure.
authors.affiliation: Laboratory of Plastics and Rubber Technology, Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest, Hungary.
authors.forename: András
authors.initials: A
authors.lastname: Sudár
authors.forename: María J
authors.initials: MJ
authors.lastname: López
authors.forename: Gergely
authors.initials: G
authors.lastname: Keledi
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Vargas-García
authors.forename: Francisca
authors.initials: F
authors.lastname: Suárez-Estrella
authors.forename: Joaquín
authors.initials: J
authors.lastname: Moreno
authors.forename: Christoph
authors.initials: C
authors.lastname: Burgstaller
authors.forename: Béla
authors.initials: B
authors.lastname: Pukánszky
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects; D001673:Biodegradation, Environmental; D054750:Ecotoxicology; D020724:Elastomers / Q000737:chemistry; D005658:Fungi / Q000254:growth & development / Q000378:metabolism*; D008298:Maleates / Q000737:chemistry; D011126:Polypropylenes / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity*; D059027:Recycling; D014934:Wood / Q000737:chemistry*
chemical_list: D020724:Elastomers; D008298:Maleates; D011126:Polypropylenes; C030272:maleic acid
keywords: Biodeterioration; Fungal colonization; Leaching; Maleated ethylene-propylene-diene; Vibrio fischeri