Release of Graphene and Carbon Nanotubes from Biodegradable Poly(Lactic Acid) Films during Degradation and Combustion: Risk Associated with the End-of-Life of Nanocomposite Food Packaging Materials

Nanoparticles of graphene and carbon nanotubes are attractive materials for the improvement of mechanical and barrier properties and for the functionality of biodegradable polymers for packaging applications. However, the increase of the manufacture and consumption increases the probability of exposure of humans and the environment to such nanomaterials; this brings up questions about the risks of nanomaterials, since they can be toxic. For a risk assessment, it is crucial to know whether airborne nanoparticles of graphene and carbon nanotubes can be released from nanocomposites into the environment at their end-life, or whether they remain embedded in the matrix. In this work, the release of graphene and carbon nanotubes from the poly(lactic) acid nanocomposite films were studied for the scenarios of: (i) biodegradation of the matrix polymer at the disposal of wastes; and (ii) combustion and fire of nanocomposite wastes. Thermogravimetric analysis in air atmosphere, transmission electron microscopy (TEM), atomic force microscopy (AFM) and scanning electron microscope (SEM) were used to verify the release of nanoparticles from nanocomposite films. The three factors model was applied for the quantitative and qualitative risk assessment of the release of graphene and carbon nanotubes from nanocomposite wastes for these scenarios. Safety concern is discussed in respect to the existing regulations for nanowaste stream.

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Release of Graphene and Carbon Nanotubes from Biodegradable Poly(Lactic Acid) Films during Degradation and Combustion: Risk Associated with the End-of-Life of Nanocomposite Food Packaging Materials

10.20944/preprints201810.0692.v1 ◽

2018 ◽

Author(s):

Stanislav Kotsilkov ◽

Evgeni Ivanov ◽

Nikolay Vitanov

Keyword(s):

Risk Assessment ◽

Carbon Nanotubes ◽

Lactic Acid ◽

Food Packaging ◽

Safety Concern ◽

Barrier Properties ◽

Nanocomposite Films ◽

Poly Lactic Acid ◽

Air Atmosphere ◽

Qualitative Risk Assessment

Nanoparticles of graphene and carbon nanotubes are attractive materials for improvement of mechanical and barrier properties and functionality of biodegradable polymers for food packaging applications. However, the increase of the manufacture and consumption increases the probability of exposure of human and environment to such nanomaterials, this rising questions about the risks of nanomaterials since they can be toxic. For a risk assessment, it is crucial to know whether airborne nanoparticles of graphene and carbon nanotubes can be released from nanocomposites into the environment at their end-life, or they remain embedded in the matrix. In this work the release of graphene and carbon nanotubes from the poly(lactic) acid nanocomposite films were studied for the scenarios of: (i) biodegradation of matrix polymer at the disposal of wastes; and (ii) combustion and fire of nanocomposite wastes. Thermogravimetric analysis in air atmosphere, TEM, AFM and SEM were used to verify the release of nanoparticles from nanocomposite films. The three factors model was applied for the quantitative and qualitative risk assessment to the release of graphene and carbon nanotubes from nanocomposite wastes for these scenarios. Safety concern is discussed in respect to the existing regulations for nanowastes stream.

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The Effect of Nanofillers on the Functional Properties of Biopolymer-Based Films: A Review

Polymers ◽

10.3390/polym11040675 ◽

2019 ◽

Vol 11 (4) ◽

pp. 675 ◽

Cited By ~ 41

Author(s):

Ewelina Jamróz ◽

Piotr Kulawik ◽

Pavel Kopel

Keyword(s):

Functional Properties ◽

Carbon Nanostructures ◽

Food Packaging ◽

Raw Materials ◽

Antioxidant Properties ◽

Barrier Properties ◽

Nanocomposite Films ◽

Poly Lactic Acid ◽

The Matrix ◽

Degradable Plastics

Waste from non-degradable plastics is becoming an increasingly serious problem. Therefore, more and more research focuses on the development of materials with biodegradable properties. Bio-polymers are excellent raw materials for the production of such materials. Bio-based biopolymer films reinforced with nanostructures have become an interesting area of research. Nanocomposite films are a group of materials that mainly consist of bio-based natural (e.g., chitosan, starch) and synthetic (e.g., poly(lactic acid)) polymers and nanofillers (clay, organic, inorganic, or carbon nanostructures), with different properties. The interaction between environmentally friendly biopolymers and nanofillers leads to the improved functionality of nanocomposite materials. Depending on the properties of nanofillers, new or improved properties of nanocomposites can be obtained such as: barrier properties, improved mechanical strength, antimicrobial, and antioxidant properties or thermal stability. This review compiles information about biopolymers used as the matrix for the films with nanofillers as the active agents. Particular emphasis has been placed on the influence of nanofillers on functional properties of biopolymer films and their possible use within the food industry and food packaging systems. The possible applications of those nanocomposite films within other industries (medicine, drug and chemical industry, tissue engineering) is also briefly summarized.

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Nanocomposites Materials of PLA Reinforced with Nanoclays Using a Masterbatch Technology: A Study of the Mechanical Performance and Its Sustainability

Polymers ◽

10.3390/polym13132133 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2133

Author(s):

Helena Oliver-Ortega ◽

Josep Tresserras ◽

Fernando Julian ◽

Manel Alcalà ◽

Alba Bala ◽

...

Keyword(s):

Food Packaging ◽

Mechanical Performance ◽

Polymeric Materials ◽

Barrier Properties ◽

Food Tray ◽

Environmental Concerns ◽

Poly Lactic Acid ◽

The Matrix ◽

Surface Modified ◽

Being Moved

Packaging consumes around 40% of the total plastic production. One of the most important fields with high requirements is food packaging. Food packaging products have been commonly produced with petrol polymers, but due to environmental concerns, the market is being moved to biopolymers. Poly (lactic acid) (PLA) is the most promising biopolymer, as it is bio-based and biodegradable, and it is well established in the market. Nonetheless, its barrier properties need to be enhanced to be competitive with other polymers such as polyethylene terephthalate (PET). Nanoclays improve the barrier properties of polymeric materials if correct dispersion and exfoliation are obtained. Thus, it marks a milestone to obtain an appropriate dispersion. A predispersed methodology is proposed as a compounding process to improve the dispersion of these composites instead of common melt procedures. Afterwards, the effect of the polarity of the matrix was analyzing using polar and surface modified nanoclays with contents ranging from 2 to 8% w/w. The results showed the suitability of the predispersed and concentrated compound, technically named masterbatch, to obtain intercalated structures and the higher dispersion of polar nanoclays. Finally, the mechanical performance and sustainability of the prepared materials were simulated in a food tray, showing the best assessment of these materials and their lower fingerprint.

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Multifunctional PLA Blends Containing Chitosan Mediated Silver Nanoparticles: Thermal, Mechanical, Antibacterial, and Degradation Properties

Nanomaterials ◽

10.3390/nano10010022 ◽

2019 ◽

Vol 10 (1) ◽

pp. 22 ◽

Cited By ~ 8

Author(s):

Agueda Sonseca ◽

Salim Madani ◽

Gema Rodríguez ◽

Víctor Hevilla ◽

Coro Echeverría ◽

...

Keyword(s):

Thermal Stability ◽

Silver Nanoparticles ◽

Lactic Acid ◽

Food Packaging ◽

Synthesis Method ◽

Crystallization Rate ◽

Poly Lactic Acid ◽

Scanning Calorimetry ◽

The Matrix ◽

Degradation Properties

Poly(lactic acid) (PLA) is one of the most commonly employed synthetic biopolymers for facing plastic waste problems. Despite its numerous strengths, its inherent brittleness, low toughness, and thermal stability, as well as a relatively slow crystallization rate represent some limiting properties when packaging is its final intended application. In the present work, silver nanoparticles obtained from a facile and green synthesis method, mediated with chitosan as a reducing and stabilizing agent, have been introduced in the oligomeric lactic acid (OLA) plasticized PLA in order to obtain nanocomposites with enhanced properties to find potential application as antibacterial food packaging materials. In this way, the green character of the matrix and plasticizer was preserved by using an eco-friendly synthesis protocol of the nanofiller. The X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results proved the modification of the crystalline structure as well as the crystallinity of the pristine matrix when chitosan mediated silver nanoparticles (AgCH-NPs) were present. The final effect over the thermal stability, mechanical properties, degradation under composting conditions, and antimicrobial behavior when AgCH-NPs were added to the neat plasticized PLA matrix was also investigated. The obtained results revealed interesting properties of the final nanocomposites to be applied as materials for the targeted application.

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Hybrid Biocomposites Based on Poly(Lactic Acid) and Silica Aerogel for Food Packaging Applications

Materials ◽

10.3390/ma13214910 ◽

2020 ◽

Vol 13 (21) ◽

pp. 4910 ◽

Cited By ~ 1

Author(s):

Alejandro Aragón-Gutierrez ◽

Marina P. Arrieta ◽

Mar López-González ◽

Marta Fernández-García ◽

Daniel López

Keyword(s):

Thermal Stability ◽

Lactic Acid ◽

Silica Aerogel ◽

Food Packaging ◽

Mechanical Performance ◽

Composite Films ◽

Barrier Properties ◽

Extrusion Process ◽

Poly Lactic Acid ◽

Barrier Performance

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.

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Effect of chitosan addition in starch and poly(lactic acid) sheets produced by extrusion

Revista Brasileira de Pesquisa em Alimentos ◽

10.14685/rebrapa.v6i1.208 ◽

2015 ◽

Vol 6 (1) ◽

pp. 80

Author(s):

Matheus Luz Alberti ◽

Sílvio José De Souza ◽

Heliberto Gonçalves ◽

Fabio Yamashita ◽

Marianne Ayumi Shirai

Keyword(s):

Lactic Acid ◽

Water Vapor ◽

Food Packaging ◽

Water Vapor Permeability ◽

Barrier Properties ◽

Extrusion Process ◽

Pilot Scale ◽

Poly Lactic Acid ◽

Vapor Permeability ◽

Water Vapor Barrier

The use of blends containing biodegradable polymers like starch and poly (lactic acid) (PLA) has gained considerable attention, especially for the food packaging production. Current research has also highlighted the use of chitosan because their antimicrobial activity, biodegradability and applicability in the production of active biodegradable food packaging. The objective of this work was to produce cassava starch and PLA sheets incorporated with chitosan by flat extrusion process (calendering-extrusion), and evaluate the mechanical, water vapor barrier and microstructural properties. In order to simplify the obtainment of the material reducing processing steps, all components of the blend were homogenized in one step extrusion The incorporation of chitosan in the starch/PLA sheets decreased significantly the tensile strength, Young's modulus, elongation at break and density. In addition, the scanning electron microscopy images showed the formation of non-homogeneous mixtures with the presence of pores between the blend compounds, and this fact affected the water vapor barrier properties increasing water vapor permeability, solubility and diffusion coefficients. It was possible to conclude that although the incorporation of chitosan to the starch/PLA sheets has not contributed to obtain materials with suitable properties, it was able to produce them by calendering-extrusion process in pilot scale. Studies about chitosan incorporation in starch and PLA sheets still needed. DOI: 10.14685/rebrapa.v6i1.208

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Barrier Properties and Hydrophobicity of Biodegradable Poly(lactic acid) Composites Reinforced with Recycled Chinese Spirits Distiller’s Grains

Polymers ◽

10.3390/polym13172861 ◽

2021 ◽

Vol 13 (17) ◽

pp. 2861

Author(s):

Zhi-Jun Chen ◽

Chi-Hui Tsou ◽

Meng-Lin Tsai ◽

Jipeng Guo ◽

Manuel Reyes De Guzman ◽

...

Keyword(s):

Mechanical Properties ◽

Lactic Acid ◽

Barrier Properties ◽

Poly Lactic Acid ◽

Control Group ◽

Scanning Calorimetry ◽

Melt Mixing ◽

Distiller's Grains ◽

The Matrix ◽

Section Structure

Adding natural biomass to poly(lactic acid) (PLA) as a reinforcing filler is a way to change the properties of PLA. This paper is about preparing PLA/biomass composites by physically melting and blending Chinese Spirits distiller’s grains (CSDG) biomass and PLA to optimize the composite performance. Composites of modified PLA (MPLA) with varying amounts of CSDG were also prepared by the melt-mixing method, and unmodified PLA/CSDG composites were used as a control group for comparative analysis. The functional groups of MPLA enhanced the compatibility between the polymer substrate and CSDG. The composite water vapor/oxygen barrier and mechanical properties were studied. It was found that the barrier and mechanical properties of MPLA/CSDG composites were significantly improved. SEM was adopted to examine the tensile section structure of the composites, and the compatibility between the filler and the matrix was analyzed. An appropriate amount of CSDG had a better dispersibility in the matrix, and it further improved the interfacial bonding force, which in turn improved the composite mechanical properties. X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry were conducted to determine the crystalline properties and to analyze the stability of the composites. It was found that the CSDG content had a significant effect on the crystallinity. Barrier and biodegradation mechanisms were also discussed.

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A Review on Barrier Properties of Poly(Lactic Acid)/Clay Nanocomposites

Polymers ◽

10.3390/polym12051095 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1095 ◽

Cited By ~ 3

Author(s):

Shuvra Singha ◽

Mikael S. Hedenqvist

Keyword(s):

Lactic Acid ◽

Mass Transport ◽

Food Packaging ◽

In Situ Polymerization ◽

Barrier Properties ◽

Melt Processing ◽

Effective Length ◽

Poly Lactic Acid ◽

Clay Nanocomposites ◽

Solution Intercalation

Poly(lactic acid) (PLA) is considered to be among the best biopolymer substitutes for the existing petroleum-based polymers in the field of food packaging owing to its renewability, biodegradability, non-toxicity and mechanical properties. However, PLA displays only moderate barrier properties to gases, vapors and organic compounds, which can limit its application as a packaging material. Hence, it becomes essential to understand the mass transport properties of PLA and address the transport challenges. Significant improvements in the barrier properties can be achieved by incorporating two-dimensional clay nanofillers, the planes of which create tortuosity to the diffusing molecules, thereby increasing the effective length of the diffusion path. This article reviews the literature on barrier properties of PLA/clay nanocomposites. The important PLA/clay nanocomposite preparation techniques, such as solution intercalation, melt processing and in situ polymerization, are outlined followed by an extensive account of barrier performance of nanocomposites drawn from the literature. Fundamentals of mass transport phenomena and the factors affecting mass transport are also presented. Furthermore, mathematical models that have been proposed/used to predict the permeability in polymer/clay nanocomposites are reviewed and the extent to which the models are validated in PLA/clay composites is discussed.

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