Abstract
Bionanocomposites based on poly (lactic acid) (PLA) and silica aerogel (SiA) were developed by means of melt extrusion process. PLA-SiA composite films were plasticized with 15 wt.% of acetyl (tributyl citrate) (ATBC) to facilitate the PLA processability as well as to attain flexible polymeric formulations for films for food packaging purposes. Meanwhile, SiA was added in four different proportions (0.5, 1, 3 and 5 wt.%) to evaluate the ability of SiA to improve the thermal, mechanical, and barrier performance of the bionanocomposites. The mechanical performance, thermal stability as well as the barrier properties against different gases (carbon dioxide, nitrogen, and oxygen) of the bionanocomposites were evaluated. It was observed that the addition of 3 wt.% of SiA to the plasticized PLA-ATBC matrix showed simultaneously an improvement on the thermal stability as well as the mechanical and barrier performance of films. Finally, PLA-SiA film formulations were disintegrated in compost at the lab-scale level. The combination of ATBC and SiA sped up the disintegration of PLA matrix. Thus, the bionanocomposites produced here show great potential as sustainable polymeric formulations with interest in the food packaging sector.
Highlights
As a result of environmental awareness, the use of the petrochemical resources to produce short term plastics products as well as the disposal of large amounts of waste from daily use polymers, such as food packaging, is among one of the foremost concerns in current times
The visual appearance of the PLA-acetyl tributyl citrate (ATBC)-SiA3% film formulation is showed in Figure 1a as an example
The incorporation of the silica aerogel in 0.5, 1, 3, and 5 wt.% resulted in a small improvement in the thermal stability of the biocomposites
Summary
As a result of environmental awareness, the use of the petrochemical resources to produce short term plastics products as well as the disposal of large amounts of waste from daily use polymers, such as food packaging, is among one of the foremost concerns in current times. Materials 2020, 13, 4910 film applications intended for agricultural mulch films or food packaging, such as high transparency, excellent printability, availability in the market, economically competitive, ease of processing by the already existing technologies in the plastic processing industry (i.e., melt-blending, extrusion, injection molding and film forming), and it presents inherent environmentally friendly characteristics (i.e., it is biobased and biodegradable) [2,3,5] In this sense, it is synthesized by the ring opening polymerization of lactide (LA) which in turn is coming from the fermentation of renewable agricultural crops (corn, sugar-cane and other polysaccharides). PLA based products can be wasted along with organic waste instead of being discarded with the rest of plastic materials [10]
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