scholarly journals Influence of thymol and silver nanoparticles on the degradation of poly(lactic acid) based nanocomposites: Thermal and morphological properties

2014 ◽  
Vol 108 ◽  
pp. 158-165 ◽  
Author(s):  
Marina Ramos ◽  
Elena Fortunati ◽  
Mercedes Peltzer ◽  
Franco Dominici ◽  
Alfonso Jiménez ◽  
...  
2014 ◽  
Vol 970 ◽  
pp. 312-316
Author(s):  
Sujaree Tachaphiboonsap ◽  
Kasama Jarukumjorn

Thermoplastic starch (TPS)/poly (lactic acid) (PLA) blend and thermoplastic starch (TPS)/poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blend were prepared by melt blending method. PLA grafted with maleic anhydride (PLA-g-MA) was used as a compatibilizer to improve the compatibility of the blends. As TPS was incorporated into PLA, elongation at break was increased while tensile strength, tensile modulus, and impact strength were decreased. Tensile properties and impact properties of TPS/PLA blend were improved with adding PLA-g-MA indicating the enhancement of interfacial adhesion between PLA and TPS. With increasing PBAT content, elongation at break and impact strength of TPS/PLA blends were improved. The addition of TPS decreased glass transition temperature (Tg), crystallization temperature (Tc), and melting temperature (Tm) of PLA. Tgand Tcof TPS/PLA blend were decreased by incorporating PLA-g-MA. However, the presence of PBAT reduced Tcof TPS/PLA blend. Thermal properties of TPS/PLA/PBAT blends did not change with increasing PBAT content. SEM micrographs revealed that the compatibilized TPS/PLA blends exhibited finer morphology when compared to the uncompatibilized TPS/PLA blend.


2021 ◽  
pp. 088532822110464
Author(s):  
Alexandre F Júnior ◽  
Charlene A Ribeiro ◽  
Maria E Leyva ◽  
Paulo S Marques ◽  
Carlos R J Soares ◽  
...  

The aim of this work was to study the biophysical properties of the chitosan-grafted poly(lactic acid) (CH-g-PLA) nanofibers loaded with silver nanoparticles (AgNPs) and chondroitin-4-sulfate (C4S). The electrospun CH-g-PLA:AgNP:C4S nanofibers were manufactured using the electrospinning technique. The microstructure of the CH-g-PLA:AgNP:C4S nanofibers was investigated by proton nuclear magnetic resonance (1H-NMR), scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), and Fourier transform infrared (ATR-FTIR) spectroscopy. ATR-FTIR and 1H-NMR confirm the CH grafting successfully by PLA with a substitution degree of 33.4%. The SEM measurement results indicated apparently smooth nanofibers having a diameter range of 340 ± 18 nm with porosity of 89 ± 3.08% and an average pore area of 0.27 μm2. UV-Vis and XRD suggest that silver nanoparticles with the size distribution of 30 nm were successfully incorporated into the electrospun nanofibers. The water contact angle of 12.8 ± 2.7° reveals the hydrophilic nature of the CH-g-PLA:AgNP:C4S nanofibers has been improved by C4S. The electrospun CH-g-PLA:AgNP:C4S nanofibers are found to release ions Ag+ at a concentration level capable of rendering an antimicrobial efficacy. Gram-positive bacteria ( S.aureus) were more sensitive to CH-g-PLA:AgNP:C4S than Gram-negative bacteria ( E. coli). The electrospun CH-g-PLA:AgNP:C4S nanofibers exhibited no cytotoxicity to the L-929 fibroblast cells, suggesting cytocompatibility. Fluorescence microscopy demonstrated that C4S promotes the adhesion and proliferation of fibroblast cells onto electrospun CH-g-PLA:AgNP:C4S nanofibers.


Aerospace ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 120 ◽  
Author(s):  
Barbara Tse ◽  
Xueli Yu ◽  
Hugh Gong ◽  
Constantinos Soutis

Recycling carbon fibre is crucial in the reduction of waste from the increasing use of carbon fibre reinforced composites in industry. The reclaimed fibres, however, are usually short and discontinuous as opposed to the continuous virgin carbon fibre. In this work, short recycled carbon fibres (rCF) were mixed with flax and poly-lactic acid (PLA) fibres acting as the matrix to form nonwoven mats through wet-laying. The mats were compression moulded to produce composites with different ratios of rCF and flax fibre in the PLA matrix. Their flexural behaviour was examined through three-point-bending tests, and their morphological properties were characterised with scanning electron and optical microscopes. Experimental data showed that the flexural properties increased with higher rCF content, with the maximum being a flexural modulus of approximately 14 GPa and flexural strength of 203 MPa with a fibre volume fraction of 75% rCF and 25% flax fibre. The intimate mixing of the fibres contributed to a lesser reduction of flexural properties when increasing the flax fibre content.


Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 22 ◽  
Author(s):  
Agueda Sonseca ◽  
Salim Madani ◽  
Gema Rodríguez ◽  
Víctor Hevilla ◽  
Coro Echeverría ◽  
...  

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.


2015 ◽  
Vol 23 (3) ◽  
pp. 316-320 ◽  
Author(s):  
Giuliana Gorrasi ◽  
Andrea Sorrentino ◽  
Roberto Pantani

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