Long-term durability and ecotoxicity of biocomposites in marine environments: a review

Abstract

Long term durability and moisture ingress effects on the mechanical property is highlighted where tensile strength is reduced as the moisture immersion time increases showing weak fibre matrix interfaces evidenced from SEM micrograph.

The ecotoxicological consequences of microplastics and co-contaminants in aquatic organisms: a mini-review

“…During the manufacturing of plastics various substances often termed as 'additives' are combined with the polymeric resins to improve the properties of final applications and a few other reaction by-products will be further accidentally incorporated [2,19,20]. When plastic debris reach aquatic environments, these endogenous substances, some of which are known to be toxic to biota, can migrate from the resin to the external medium, as substances are often physically, rather than chemically, bonded to the main polymer matrix [20]. The leaching of substances from MPs may occur at higher rates compared with macroplastic litter due to their increased surface area to volume ratio.…”

“…Some endogenous chemicals found in aquatic environments are known to have toxicological properties, such as phthalates, bisphenol A (BPA), nonylphenol (NP) and brominated flame retardants (BFR) [19], as well as trace metals such as cadmium (Cd), lead (Pb), antimony (Sb) and tin (Sn) [2]. Of concern are the leaching rates of endogenous chemicals from weathered MPs [20], in particular when in gastrointestinal fluids during digestion where high levels of surfactants and lower pH may facilitate the migration process of compounds from the plastic resin [23]. Gut retention times of MPs vary amongst invertebrate species depending on physiology and relative MP size and shape and can last between a few hours and weeks.…”

“…weathering) of MPs increases their adsorption affinity towards contaminants, but this parameter has seldom been considered in the effect assessments of MPs. The weathering of plastics in environmental settings is affected by exposure to UV radiation (sunlight), temperature shifts, humidity, and oxygen and ozone levels [69][70][71], and in turn the weathering of MPs can further play an important role in the leachates released and toxicity to organisms [20,72,73]. Furthermore, as climatic conditions shift due to global change (e.g.…”

“…The term 'bioplastics' may encompass both bio-based plastics made from renewable or natural sources (i.e. plant material) and biodegradable plastics that are made from materials which can be subject to enzymatic degradation of the polymeric matrix [20]. Thus, whilst conventional wisdom would say that bioplastics are designed to degrade faster than conventional plastics, there is specificity to the conditions of degradation, such as the right medium (water, soil, compost), and the absence of such conditions may result in a longer than expected residence time in the environment [80].…”

Effects of Hydration on Mechanical Properties of Acylated Hydroxyapatite–Starch Composites

“…Similar effects of water on the mechanical properties of polymer composites were reviewed. 24,25 To reproduce the properties of bone with higher toughness in the presence of water, we propose that the polymer to be hybridized should be amphiphilic, the polar functional groups for nucleation of hydroxyapatite crystals and binding to the hydroxyapatite surface, and the nonpolar groups for water resistance. We have reported that composites of an amphiphilic polymer, poly-(ethylene terephthalate), carrying carboxylate groups with hydroxyapatite were water-resistant, and toughness of the compacts was higher when the compacts were immersed in water.…”