Evaluation of Mechanical and Interfacial Properties of Bio-Composites Based on Poly(Lactic Acid) with Natural Cellulose Fibers

Abstract

The circular economy policy and the interest for sustainable material are inducing a constant expansion of the bio-composites market. The opportunity of using natural fibers in bio-based and biodegradable polymeric matrices, derived from industrial and/or agricultural waste, represents a stimulating challenge in the replacement of traditional composites based on fossil sources. The coupling of bioplastics with natural fibers in order to lower costs and promote degradability is one of the primary objectives of research, above all in the packaging and agricultural sectors where large amounts of non-recyclable plastics are generated, inducing a serious problem for plastic disposal and potential accumulation in the environment. Among biopolymers, poly(lactic acid) (PLA) is one of the most used compostable, bio-based polymeric matrices, since it exhibits process ability and mechanical properties compatible with a wide range of applications. In this study, two types of cellulosic fibers were processed with PLA in order to obtain bio-composites with different percentages of microfibers (5%, 10%, 20%). The mechanical properties were evaluated (tensile and impact test), and analytical models were applied in order to estimate the adhesion between matrix and fibers and to predict the material’s stiffness. Understanding these properties is of particular importance in order to be able to tune and project the final characteristics of bio-composites.

Evaluation of Mussel Shells Powder as Reinforcement for PLA-Based Biocomposites

“…Micro-cavitation and micro-debonding can occur, introducing cracks of significant sizes [ 44 ]. Calcium carbonate can give rise to an improvement in fracture toughness when the mechanism of debonding is triggered in the presence of brittle matrices [ 45 ]. Charpy impact strength values test , performed on the PLA/PBAT biocomposites with mussel shell powder (see the last column of Table 3 ) revealed that the energy absorbed was approximately half with respect to that of the ductile matrix.…”

Sustainable Micro and Nano Additives for Controlling the Migration of a Biobased Plasticizer from PLA-Based Flexible Films

“…This is a commercial grade containing about 4% of D-lactic acid units that lower the melting point and the crystallization tendency, improving the processing ability. This PLA, according to the producer's data sheet has a density of 1.24 g/cm 3 3 and a molecular weight of 402.5 g/mol.…”

“…This problem has encouraged research and industrial interest on biobased and biodegradable polymers that could overcome sustainability issues and environmental challenges posed by the production and disposal of oil-derived plastics [1,2]. In packaging and agriculture applications, the use of bio-based biodegradable polymers is a strong advantage both for environment and customers [3]. However, it is expected that the demand for these biopolymers will increase and, over the coming few decades, bioplastic materials can complement and gradually substitute the oil-based plastics in different sectors [2,4].…”

“…2AV has a micrometric particle size with a diameter value (relative to the maximum distribution curve, d 98% ) of 15 µm, and 38% of particles of diameter less than 2 µm. The average statistical diameter (d 50% ) is 2.6 µm with a specific weight of 2.7 g/cm 3 . Smartfill is fine ground and surface fatty acid treated calcium carbonate having 55% of particles with an average diameter <2 µm (bulk density: 1.1 g/mL).…”

Bio-Based Packaging: Materials, Modifications, Industrial Applications and Sustainability

“…The addition of polysaccharidic fibers in biopolyesters, such as PLA-based blends, as reinforcing agent [ 149 ] is a well-known alternative for producing micro- or nano-biocomposites [ 151 , 152 ]. In general, the mechanical properties of a biocomposite result from the matrix and fiber properties as well as the adhesion between the fibers and the matrix [ 153 , 154 ]. The tensile strength highly depends on the adhesion between the fibers and the matrix, whereas the tensile modulus is highly influenced by the distribution and orientation of the fibers and their length-to-width ratio (aspect ratio).…”