Biodegradable PLA based nanocomposites for packaging applications: The effects of organo‐modified bentonite concentration

Abstract

The effects of concentration and surface modification of two Brazilian bentonite clays on nanocomposites' properties based on polylactic acid – (PLA) were investigated. The samples were prepared by the extrusion/injection method to obtain biodegradable packaging plastics. The raw materials and their bionanocomposites were characterized by various techniques. Natural clay samples presented a size of around 2 μm while the modified ones' size was 5–6 μm, probably due to the presence of cetyltrimethylammonium bromide in the interlayer space. The particle size and the contact angle increased with the treatment and the clay's density decreased. The organoclays were homogeneously dispersed in PLA, which can be associated with the interactions between PLA chains' carbonyl groups and the organoclays. The bionanocomposites present modified clay particles axis aligned to the flow direction of the extruder/injector. Chocolate organoclay acts as a nucleating agent to PLA crystal growth, increasing the sample's crystallinity, while Bofe organoclay interferes with the amorphous chain's mobility and diminishes the sample's crystallization. The addition of both organoclays to PLA diminished the sample's elongation at break and strength, although the organoclays increased the sample's Young modulus, even though Bofe organoclay is more active in PLA amorphous phase and Chocolate organoclay on the crystalline one.

Thermal Stability and Decomposition Mechanism of PLA Nanocomposites with Kraft Lignin and Tannin

“…The extended range of its applications can be outlined by its use from the biomedical and bioengineering field [5][6][7] to packaging and everyday-life products [1,[8][9][10]. In a more specific context, this aliphatic polyester has been employed for the construction of 3D-printed structures utilized Polymers 2021, 13, 2818 2 of 16 to fulfil several purposes [11][12][13], whereas its application for the preparation of materials with advanced antimicrobial and antioxidant surfaces should also be highlighted [8,[14][15][16].…”

Impacts of cellulose nanofibers on the morphological behavior and dynamic mechanical thermal properties of extruded polylactic acid/cellulose nanofibril nanocomposite foam

“…8 Polylactic acid (PLA) is the most developed commercial biodegradable linear aliphatic polyester that can be perfectly degraded into carbon dioxide and water in the natural environment. 9,10 This polymer has been considered in biomedical applications such as tissue engineering, implants, drug delivery systems, and orthopedic devices due to its good tensile strength, as well as its reproducibility and biodegradability. [11][12][13][14] Nonetheless, the brittleness, slow crystallization, and higher cost of PLA are some of the drawbacks for its wider application compared to petroleum-derived plastic.…”

Plasticized polyvinyl chloride/melamine‐cyanurate modified Mg(OH)2@bentonite nanocomposites; mechanical, thermal, and flame retardant properties

“…When organic modifiers are used, the surface hydrophilicity of modified bentonite decreases and leads to an increase in the interlayer basal spacing and compatibility with low or non-polar polymer matrices. 29,30 In other words, to prepare polymer nanocomposites with desirable properties, the uniform dispersion of nano clays is highly dependent on the polarity of the polymer matrix. As it is clear, the uniform dispersion of polar layered nanoparticles in non-polar polymers is not possible, while it is possible in polar polymers such as polyamides, ethylene vinyl acetate (EVA), and thermoplastic polyurethanes (TPU).…”

“…These exchangeable cations can be exchanged with organic cations. When organic modifiers are used, the surface hydrophilicity of modified bentonite decreases and leads to an increase in the interlayer basal spacing and compatibility with low or non‐polar polymer matrices 29,30 . In other words, to prepare polymer nanocomposites with desirable properties, the uniform dispersion of nano clays is highly dependent on the polarity of the polymer matrix.…”