Combined effect of cellulose nanocrystals, carvacrol and oligomeric lactic acid in PLA_PHB polymeric films

Abstract

Biodegradable multicomponent films based on poly(lactic acid) (PLA) and poly(3hydroxybutyrate) (PHB) plasticized with oligomeric lactic acid (OLA), reinforced with synthetized cellulose nanocrystals (CNC) and modified by a natural additive with antimicrobial activity (carvacrol) were formulated and processed by extrusion. Morphological, mechanical, thermal, migration and barrier properties were tested to determine the effect of different components in comparison with neat poly(lactic acid). Results showed the positive effect of CNC in the five components based films, with the increase of the Young's modulus of the PLA_PHB_10Carv_15OLA, associated with an increase in the elongation at break (from 130% to 410%), by showing an OTR reduction of 67%. Disintegrability in compost conditions and enzymatic degradation were tested to evaluate the post-use of these films. All formulations disintegrated in less than 17 days, while proteinase K preferentially degraded the amorphous regions, and crystallinity degree of the nanocomposite films increased as a consequence of enzyme action.

Pullulan Films Containing Rockrose Essential Oil for Potential Food Packaging Applications

“…Contrariwise to what was observed for water vapor permeability, the incorporation of rockrose EO in the pullulan films significantly increased ( p -value < 0.05) their oxygen permeability ( Table 7 ), which is probably linked to the plasticizing effect of the EO, as other authors reported when adding carvacrol to biopolymeric composite films [ 48 ]. Further studies will be needed to better understand the increase in oxygen permeability of the pullulan films when rockrose EO is incorporated, and to overcome this drawback.…”

“…The entrapment of water inside the polysaccharide-based films has been previously explained, and is related to possible interactions among polysaccharide molecules and the hydroxyl groups of glycerol, leading to a more compact polymeric network [47]. Contrariwise to what was observed for water vapor permeability, the incorporation of rockrose EO in the pullulan films significantly increased (p-value < 0.05) their oxygen permeability (Table 7), which is probably linked to the plasticizing effect of the EO, as other authors reported when adding carvacrol to biopolymeric composite films [48]. Further studies will be needed to better understand the increase in oxygen permeability of the pullulan films when rockrose EO is incorporated, and to overcome this drawback.…”

UV Protective, Antioxidant, Antibacterial and Compostable Polylactic Acid Composites Containing Pristine and Chemically Modified Lignin Nanoparticles

“…The surface whitening of PLA has frequently been read as a signal of hydrolytic degradation, which induces a change in the refractive index of the material as a consequence of water absorption and/or formation of low molecular weight degradation products [86]. Visible fractures appeared at 7 days as previously reported for similar systems [14,87]. Fragmentation continued for all samples assayed during the following days, and after 17 days no considerable amount of remaining materials was visible to the naked eye.…”

Thermal and Crystallization Behavior of PLA/PLLA-Grafting Cellulose Nanocrystal

“…Accumulation of plastic objects and particles as plastic bottles, bags and microbeads in the Earth's environment has adversely affected wildlife habitat and humans. Thus, in recent years, there has been a growing interest in the development of environmentally friendly materials, as well as a need to replace synthetic polymers by biodegradable polymer materials, such as poly(lactic acid) (PLA), especially in packaging [1] [2]. Cellulose-based materials are interesting biodegradable fillers and have shown to be able to improve the properties of PLA by affecting the crystallinity, and mechanical and thermal properties [3] [4].…”