New Bio-Composites Based on Polyhydroxyalkanoates and Posidonia oceanica Fibres for Applications in a Marine Environment.

Maurizia Seggiani,Elena Balestri,Monica Puccini,Claudio Lardicci,Norma Mallegni,Andrea Lazzeri,Sandra Vitolo,Patrizia Cinelli

doi:10.3390/ma10040326

Maurizia Seggiani, Elena Balestri + Show 6 more

Open Access

https://doi.org/10.3390/ma10040326

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Abstract

Bio-composites based on polyhydroxyalkanoates (PHAs) and fibres of Posidonia oceanica (PO) were investigated to assess their processability by extrusion, mechanical properties, and potential biodegradability in a natural marine environment. PHAs were successfully compounded with PO fibres up to 20 wt % while, at 30 wt % of fibres, the addition of 10 wt % of polyethylene glycol (PEG 400) was necessary to improve their processability. Thermal, rheological, mechanical, and morphological characterizations of the developed composites were conducted and the degradation of composite films in a natural marine habitat was evaluated in a mesocosm by weight loss measure during an incubation period of six months. The addition of PO fibres led to an increase in stiffness of the composites with tensile modulus values about 80% higher for composites with 30 wt % fibre (2.3 GPa) compared to unfilled material (1.24 GPa). Furthermore, the impact energy markedly increased with the addition of the PO fibres, from 1.63 (unfilled material) to 3.8 kJ/m2 for the composites with 30 wt % PO. The rate of degradation was markedly influenced by seawater temperature and significantly promoted by the presence of PO fibres leading to the total degradation of the film with 30 wt % PO in less than six months. The obtained results showed that the developed composites can be suitable to manufacture items usable in marine environments, for example, in natural engineering interventions, and represent an interesting valorisation of the PO fibrous wastes accumulated in large amounts on coastal beaches.

Highlights

Bio-based and biodegradable polymers derived from renewable resources have attracted increasing attention over the last two decades due to their low environmental impact and no dependence on fossil resources [1,2,3,4]
The development of plastics biodegradable in marine environment is the key to prevent or mitigate in the future the problems caused by marine plastic debris [8]
Posidonia oceanica (PO) fibres show an initial limited weight loss up to 100 ◦ C attributable to the residual humidity, a 50 wt % weight loss is recorded from 250 ◦ C to 450 ◦ C corresponding to the main thermal degradation process

Summary

Introduction

Bio-based and biodegradable polymers derived from renewable resources (in particular agricultural and biomass feedstocks) have attracted increasing attention over the last two decades due to their low environmental impact and no dependence on fossil resources [1,2,3,4]. A wide variety of lignocellulosic fibres and natural fibres coming from agricultural and industrial crops, such as corn, wheat, bagasse, orange and apple peel [12,13], abaca, kenaf, hemp, flax, and jute are widely used in the production of composites in various industrial sectors, such as the automotive industry, packaging, and building [14,15]. Such a success is derived by their environmentally-friendly character, their low-cost, and interesting mechanical and physical properties comparable properties to traditional fibres, such as glass fibre [16]

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