Controlled Release, Disintegration, Antioxidant, and Antimicrobial Properties of Poly (Lactic Acid)/Thymol/Nanoclay Composites

Nano-biocomposite films based on poly (lactic acid) (PLA) were prepared by adding thymol (8 wt.%) and a commercial montmorillonite (D43B) at different concentrations (2.5 and 5 wt.%). The antioxidant, antimicrobial, and disintegration properties of all films were determined. A kinetic study was carried out to evaluate the thymol release from the polymer matrix into ethanol 10% (v/v) as food simulant. The nanostructured networks formed in binary and ternary systems were of interest in controlling the release of thymol into the food simulant. The results indicated that the diffusion of thymol through the PLA matrix was influenced by the presence of the nanoclay. Disintegration tests demonstrated that the incorporation of both additives promoted the breakdown of the polymer matrix due to the presence of the reactive hydroxyl group in the thymol structure and ammonium groups in D43B. Active films containing thymol and D43B efficiently enhanced the antioxidant activity (inhibition values higher than 77%) of the nano-biocomposites. Finally, the addition of 8 wt.% thymol and 2.5 wt.% D43B significantly increased the antibacterial activity against Escherichia coli and Staphylococcus aureus 8325-4, resulting in a clear advantage to improve the shelf-life of perishable packaged food.

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Morphology and Mechanical Properties of Poly(Lactic Acid) and Propylene-Ethylene Copolymer Blends: Effect of Organoclay Types

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.737.269 ◽

2017 ◽

Vol 737 ◽

pp. 269-274

Author(s):

Sirirat Wacharawichanant ◽

Chaninthon Ounyai ◽

Ployvaree Rassamee

Keyword(s):

Mechanical Properties ◽

Lactic Acid ◽

Tensile Properties ◽

Polymer Matrix ◽

Poly Lactic Acid ◽

Dispersed Phase ◽

Copolymer Blends ◽

Morphology Analysis ◽

Ethylene Copolymer ◽

Morphology And Mechanical Properties

The effects of four types of organoclay on morphology and mechanical properties of poly(lactic acid) (PLA)/propylene-ethylene copolymer (PEC) blends were investigated. The ratio of PLA and PEC was 80/20 by weight and the organoclay content was 5 phr. The morphology analysis showed that the addition of all oganocaly types could improve the miscibility of PLA and PEC blends due to the decreased of the domain sizes of PEC dispersed phase in the polymer matrix. The tensile properties showed Young’s modulus of the PLA/PEC blends was improved after adding clay treated surface with 25-30 wt% trimethyl stearyl ammonium.

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Effect of Silane Functionalization on Properties of Poly(Lactic Acid)/Palygorskite Nanocomposites

Inorganics ◽

10.3390/inorganics9010003 ◽

2021 ◽

Vol 9 (1) ◽

pp. 3

Author(s):

Anton Kasprzhitskii ◽

Georgy Lazorenko ◽

Alexander Kruglikov ◽

Irina Kuchkina ◽

Vadim Gorodov

Keyword(s):

Mechanical Properties ◽

Lactic Acid ◽

Polymer Matrix ◽

Covalent Bond ◽

Poly Lactic Acid ◽

Hydroxyl Groups ◽

Good Dispersion ◽

Melt Compounding

Poly(lactic acid) (PLA)/palygorskite (Paly) nanocomposites were prepared using the melt compounding technique. Paly modified by 3-aminopropyltriethoxysilane (APTES) and vinyltrimethoxysilane (VTMS) was used as nanofiller for PLA with concentrations in the 1–7 wt% range. It has been found that the functionalization allows a covalent bond between the hydroxyl groups of the Paly and the PLA matrix, evidenced by the improvement in mechanical properties. Paly modification with VTMS has better properties compared with Pale modification with APTES. This indicates a better adhesion between the Paly-VTMS and PLA matrix, and a good dispersion of the nanofiller in the polymer matrix.

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Achieving high electrical conductivity and excellent electromagnetic interference shielding in poly(lactic acid)/silver nanocomposites by constructing large-area silver nanoplates in polymer matrix

Composites Part B Engineering ◽

10.1016/j.compositesb.2019.05.003 ◽

2019 ◽

Vol 171 ◽

pp. 204-213 ◽

Cited By ~ 28

Author(s):

Jie Li ◽

Wen-Jie Peng ◽

Zeng-Ji Fu ◽

Xiao-Hong Tang ◽

Hong Wu ◽

...

Keyword(s):

Electrical Conductivity ◽

Lactic Acid ◽

Polymer Matrix ◽

Electromagnetic Interference ◽

Poly Lactic Acid ◽

High Electrical Conductivity ◽

Electromagnetic Interference Shielding ◽

Large Area ◽

Silver Nanoplates ◽

Silver Nanocomposites

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Characterization and antimicrobial properties of fluorine-rich carbon films deposited on poly(lactic acid)

Surface and Coatings Technology ◽

10.1016/j.surfcoat.2011.03.095 ◽

2011 ◽

Vol 205 ◽

pp. S552-S557 ◽

Cited By ~ 13

Author(s):

D. Boonyawan ◽

S. Sarapirom ◽

S. Tunma ◽

C. Chaiwong ◽

P. Rachtanapun ◽

...

Keyword(s):

Lactic Acid ◽

Antimicrobial Properties ◽

Carbon Films ◽

Poly Lactic Acid

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Impact of the Graphite Fillers on the Thermal Processing of Graphite/Poly(lactic acid) Composites

Materials ◽

10.3390/ma14185346 ◽

2021 ◽

Vol 14 (18) ◽

pp. 5346

Author(s):

Daniel Kaczor ◽

Kacper Fiedurek ◽

Krzysztof Bajer ◽

Aneta Raszkowska-Kaczor ◽

Grzegorz Domek ◽

...

Keyword(s):

Lactic Acid ◽

Polymer Matrix ◽

Thermal Processing ◽

Poly Lactic Acid ◽

Expandable Graphite ◽

Slight Reduction ◽

Melt Mixing ◽

Neat Polymer ◽

Industrial Grade ◽

The Impact

To assess the impact of graphite fillers on the thermal processing of graphite/poly(lactic acid) (PLA) composites, a series of the composite samples with different graphite of industrial grade as fillers was prepared by melt mixing. The average size of the graphite grains ranged between 100 µm and 6 µm. For comparative purposes, one of the carbon fillers was expandable graphite. Composites were examined by SEM, FTIR, and Raman spectroscopy. As revealed by thermogravimetric (TG) analyses, graphite filler slightly lowered the temperature of thermal decomposition of the PLA matrix. Differential scanning calorimetry (DSC) tests showed that the room temperature crystallinity of the polymer matrix is strongly affected by the graphite filler. The crystallinity of the composites determined from the second heating cycle reached values close to 50%, while these values are close to zero for the neat polymer. The addition of graphite to PLA caused a slight reduction in the oxidation induction time (OIT). The melt flow rate (MFR) of the graphite/PLA composites was lower than the original PLA due to an increase in flow resistance associated with the high crystallinity of the polymer matrix. Expandable graphite did not cause changes in the structure of the polymer matrix during thermal treatment. The crystallinity of the composite with this filler did not increase after first heating and was close to the neat PLA MFR value, which was extremely high due to the low crystallinity of the PLA matrix and delamination of the filler at elevated temperature.

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Comparison of Aging Resistance and Antimicrobial Properties of Ethylene–Norbornene Copolymer and Poly(Lactic Acid) Impregnated with Phytochemicals Embodied in Thyme (Thymus vulgaris) and Clove (Syzygium aromaticum)

International Journal of Molecular Sciences ◽

10.3390/ijms222313025 ◽

2021 ◽

Vol 22 (23) ◽

pp. 13025

Author(s):

Anna Masek ◽

Stefan Cichosz ◽

Małgorzata Piotrowska

Keyword(s):

Lactic Acid ◽

Antimicrobial Properties ◽

Tensile Tests ◽

Poly Lactic Acid ◽

Thymus Vulgaris ◽

Syzygium Aromaticum ◽

Active Centers ◽

Full Spectrum ◽

Aging Resistance ◽

Induction Times

The effects of plant-based extracts on the solar aging and antimicrobial properties of impregnated ethylene–norbornene (EN) copolymer and poly(lactic acid) (PLA) were investigated. In this study, the impregnation yield of polyolefin, lacking in active centers capable of phytochemical bonding, and polyester, abundant in active sides, was measured. Moreover, two different extracts plentiful in phytochemicals—thyme (TE) and clove (CE)—were employed in the solvent-based impregnation process. The effect of thymol and eugenol, the two main compounds embodied in the extracts, was studied as well. Interestingly, oxidation induction times (OIT) for the impregnation of EN with thyme and clove extracts were established to be, respectively, 27.7 and 39.02 min, which are higher than for thymol (18.4 min) and eugenol (21.1 min). Therefore, an aging experiment, mimicking the full spectrum of sunlight, was carried out to investigate the resistance to common radiation of materials impregnated with antioxidative substances. As expected, the experiment revealed that the natural extracts increased the shelf-life of the polymer matrix by inhibiting the degradation processes. The aging resistance was assessed based on detected changes in the materials’ behavior and structure that were examined with Fourier-transform infrared spectroscopy, contact angle measurements, color quantification, tensile tests, and hardness investigation. Such broad results of solar aging regarding materials impregnated with thyme and clove extracts have not been reported to date. Moreover, CE was found to be the most effective modifying agent for enabling material with antimicrobial activity against Escherichia coli to be obtained.

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Barrier Properties and Characterizations of Poly(lactic Acid)/ZnO Nanocomposites

Molecules ◽

10.3390/molecules25061310 ◽

2020 ◽

Vol 25 (6) ◽

pp. 1310 ◽

Cited By ~ 4

Author(s):

Zhenya Tang ◽

Fangling Fan ◽

Zhuangzhuang Chu ◽

Chunli Fan ◽

Yuyue Qin

Keyword(s):

Tensile Strength ◽

Lactic Acid ◽

Zno Nanoparticles ◽

Food Packaging ◽

Ternary Systems ◽

Poly Lactic Acid ◽

Vapor Permeability ◽

Scanning Calorimetry ◽

Electron Microscopic ◽

Nano Zno

This study aimed to reinforce the barrier performance (i.e., oxygen–gas and water–vapor permeability) of poly(lactic acid) (PLA)-based films. Acetyltributylcitrate and zinc oxide nanoparticle (nano-ZnO), serving as plasticizer and nanofiller, respectively, were blended into a PLA matrix through a solvent-volatilizing method. The structural, morphological, thermal, and mechanical performances were then studied. Scanning electron microscopic images showed a significant dispersion of nano-ZnO in PLA ternary systems with low nano-ZnO content. The interaction between PLA matrix and ZnO nanoparticles was further analyzed by Fourier-transform infrared spectroscopy. Wide-angle X-ray scattering spectroscopy demonstrated high compatibility between PLA matrix and ZnO nanoparticles. Mechanical property studies revealed good tensile strength and low flexibility. Differential scanning calorimetry curves proved that an amorphous structure mostly existed in PLA ternary systems. The improvements in barrier property and tensile strength indicated that the PLA/nano-ZnO composite films could be used for food packaging application.

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Poly(lactic acid)/Cellulose Films Produced from Composite Spheres Prepared by Emulsion-Solvent Evaporation Method

Polymers ◽

10.3390/polym11010066 ◽

2019 ◽

Vol 11 (1) ◽

pp. 66 ◽

Cited By ~ 12

Author(s):

Sónia Sousa ◽

Ana Costa ◽

Abílio Silva ◽

Rogério Simões

Keyword(s):

Lactic Acid ◽

Surface Chemistry ◽

Solvent Evaporation ◽

Degree Of Crystallinity ◽

Poly Lactic Acid ◽

Poly Vinyl Alcohol ◽

Cellulose Films ◽

Chemically Modified ◽

Biocomposite Films ◽

Biocomposite Film

The compound of poly(lactic acid) (PLA) and cellulose was made by the emulsion-solvent evaporation technique in order to obtain spheres which are then compression molded to produce a biocomposite film. The effect of the dispersant (poly(vinyl alcohol)—PVA)/PLA ratio on the spheres yield was studied. Moreover, to evaluate the effect of cellulose particle size and surface chemistry on the process yield, unbleached eucalypt kraft pulp and microcrystalline cellulose (MCC), both unmodified and physically or chemically modified were used. PLA/cellulose spheres were characterized regarding its physical properties. It was found that the spheres yield is essentially determined by the PVA/PLA ratio and the percentage of cellulose incorporation is greatly affected by the surface chemistry of cellulose. Regarding the films, DSC runs showed a significant effect of the cellulose type incorporated into PLA matrix on the cold crystallization temperature and on the degree of crystallinity of the biocomposite films. The measurement of tensile properties of the biocomposite films revealed that the strength, elongation at break and toughness (tensile energy absorption at break) of the films incorporating unmodified and chemically modified MCC were substantially improved.

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