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

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 66 ◽  
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.

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

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1878
Author(s):  
Marina Ramos ◽  
Elena Fortunati ◽  
Ana Beltrán ◽  
Mercedes Peltzer ◽  
Francesco Cristofaro ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Polymer Matrix ◽  
Antimicrobial Properties ◽  
Ternary Systems ◽  
Hydroxyl Group ◽  
Poly Lactic Acid ◽  
Biocomposite Films ◽  
Food Simulant ◽  
Packaged Food ◽  
Binary And Ternary Systems

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.

scholarly journals Hemp Fibre Reinforced Poly(Lactic Acid) Composites

2007 ◽  
Vol 29-30 ◽  
pp. 337-340 ◽  
Author(s):  
M.A. Sawpan ◽  
K.L. Pickering ◽  
Alan Fernyhough
Keyword(s):  
Lactic Acid ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hemp Fibre ◽  
Reinforcing Material ◽  
Fibre Loading ◽  
The Degree Of Crystallinity

The potential of hemp fibre as a reinforcing material for Poly(lactic acid) (PLA) was investigated. Good interaction between hemp fibre and PLA resulted in increases of 100% for Young’s modulus and 30% for tensile strength of composites containing 30 wt% fibre. Different predictive ‘rule of mixtures’ models (e.g. Parallel, Series and Hirsch) were assessed regarding the dependence of tensile properties on fibre loading. Limited agreement with models was observed. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) studies showed that hemp fibre increased the degree of crystallinity in PLA composites.

Fabrication of core-shell structured nanofibers of poly (lactic acid) and poly (vinyl alcohol) by coaxial electrospinning for tissue engineering

2018 ◽  
Vol 98 ◽  
pp. 483-491 ◽  
Author(s):  
Hamad F. Alharbi ◽  
Monis Luqman ◽  
Khalil Abdelrazek Khalil ◽  
Yasser A. Elnakady ◽  
Omar H. Abd-Elkader ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Lactic Acid ◽  
Vinyl Alcohol ◽  
Poly Lactic Acid ◽  
Poly Vinyl Alcohol ◽  
Coaxial Electrospinning ◽  
Core Shell

Effect of cellulose nanofibers from cassava pulp on physical properties of poly(lactic acid) biocomposites

2019 ◽  
Vol 33 (8) ◽  
pp. 1094-1108
Author(s):  
Thanh Chi Nguyen ◽  
Chaiwat Ruksakulpiwat ◽  
Yupaporn Ruksakulpiwat
Keyword(s):  
Lactic Acid ◽  
Cellulose Nanofibers ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Melt Mixing ◽  
Cassava Pulp ◽  
Lower Temperature ◽  
Alkali Hydrolysis ◽  
Internal Mixer

Biocomposites of poly(lactic acid) (PLA) and cellulose nanofibers (CNFs) extracted from cassava pulp were successfully prepared by melt mixing in an internal mixer. CNFs were prepared from cassava pulp by submitting to alkali hydrolysis, bleaching treatment, and acid hydrolysis. The compatibility between CNFs and PLA matrix was improved using glycidyl methacrylate (GMA) grafted PLA (PLA-g-GMA) as an effective compatibilizer. Higher elongation at break and impact strength of PLA/PLA-g-GMA/CNFs biocomposites was achieved compared to that of neat PLA. PLA-g-GMA shows a strong effect on the crystallization behavior of the biocomposites. The PLA/PLA-g-GMA/CNFs biocomposites induce cold crystallization to take place at lower temperature. Higher degree of crystallinity of PLA/PLA-g-GMA/CNFs biocomposites was obtained compared to PLA/CNFs biocomposites. The mechanical and thermal properties of PLA/CNFs biocomposites at various ratios were investigated. With increasing CNFs contents, the modulus of the biocomposites increases. Thermal stability of PLA/CNFs and PLA/PLA-g-GMA/CNFs biocomposites did not change significantly compared to that of neat PLA.

Potassium sorbate release from poly(vinyl alcohol)-bacterial cellulose films

2012 ◽  
Vol 66 (2) ◽  
Author(s):  
Iuliana Jipa ◽  
Anicuta Stoica ◽  
Marta Stroescu ◽  
Loredana-Mihaela Dobre ◽  
Tanase Dobre ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
Antimicrobial Properties ◽  
Potassium Sorbate ◽  
Poly Vinyl Alcohol ◽  
Packaging Materials ◽  
Cellulose Powder ◽  
Cellulose Films ◽  
Antimicrobial Materials ◽  
Biocomposite Films ◽  
The Subject

AbstractActive packaging materials are the subject of research because their performance exceeds that of traditional packaging. From this class, antimicrobial materials extend the shelf-life of products and reduce the risk of contamination by pathogens. In this paper, new composite materials with antimicrobial properties are obtained by using polyvinyl alcohol and bacterial cellulose powder. Potassium (2E,4E)-hexa-2,4-dienoate was used as the antimicrobial agent. The films thus obtained were characterised using Fourier-transform infrared spectroscopy and scanning electron microscopy. Mass transfer phenomena concerning the release of potassium (2E,4E)-hexa-2,4-dienoate were investigated. The results indicated that the new biocomposite films could be used as antimicrobial packaging materials.

Crystallization and Thermal Degradation of Green Nanocomposites Based on Lignin Coated Cellulose Nanocrystals and Poly(Lactic Acid)

2017 ◽  
Vol 737 ◽  
pp. 256-261 ◽  
Author(s):  
Martin Boruvka ◽  
Luboš Bĕhálek
Keyword(s):  
Lactic Acid ◽  
Cellulose Nanocrystals ◽  
Raw Material ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Crystalline Cellulose ◽  
Melt Crystallization ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
Twin Screw

Cellulose is almost inexhaustible source of raw material comprising at least one-third of all biomass matter. Through deconstruction of cellulose hierarchical structure can be extracted highly crystalline cellulose nanocrystals (CNC) with impressive properties. However, the main barrier in the processing of the nanocomposites based on CNC is their inhomogeneous dispersion and distribution in the non-polar polymer matrix. In this paper is this problem addressed by use of novel hydrophobic lignin coated CNC as a biobased nucleation agents in poly (lactic acid) (PLA) nanocomposites. These green nanocomposites based on natural plant derived substances have enormous potential to replace materials originated from non-renewable resources and show promise of providing degradation back into the environment when they are no longer needed. Resulted composites prepared by twin screw extrusion and injection moulding were characterized by means of scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The addition of L-CNC (1, 2 and 3 wt. %) into PLA increased melt crystallization enthalpy and decreases the cold crystallization enthalpy. The degree of crystallinity (cc) increased from 5.6 % (virgin PLA) to 8.5 % (PLA/1-L-CNC), 10.3 % (PLA/2-L-CNC) and 10.7 % (PLA/3-L-CNC). The wide range of degradation temperatures of lignin coating has been observed starting at 100 °C.

scholarly journals Enhanced thermal decomposition kinetics of poly(lactic acid) sacrificial polymer catalyzed by metal oxide nanoparticles

RSC Advances ◽  
2015 ◽  
Vol 5 (123) ◽  
pp. 101745-101750 ◽  
Author(s):  
Lu Liu ◽  
Michael R. Zachariah ◽  
Stanislav I. Stoliarov ◽  
Jing Li
Keyword(s):  
Thermal Decomposition ◽  
Lactic Acid ◽  
Metal Oxide ◽  
Metal Oxide Nanoparticles ◽  
Solvent Evaporation ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Poly Lactic Acid ◽  
Oxide Nanoparticles ◽  
Kinetics Of

Poly Lactic Acid (PLA) and 1 wt% PLA/Fe2O3, PLA/CuO, PLA/Bi2O3 composites are prepared by solvent evaporation casting and their enhanced thermal decomposition kinetics catalyzed by low loading metal oxide nanoparticles are studied.

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