New multifunctional poly(lactide acid) composites: Mechanical, antibacterial, and degradation properties

Abstract

The aim of this work was to study the effect of the innovative combination of microcrystalline cellulose (MCC) and silver nanoparticles (Ag) on the poly (lactide acid) (PLA) composite properties, to modulate the PLA mechanical response and induce an antibacterial effect. The preparation and characterization of PLA-based composites with MCC and Ag nanoparticles by twin-screw extrusion followed by injection molding is reported. A film procedure was also performed to obtain PLA and PLA composite films with a thickness ranged between 20 and 60 lm. The analysis of disintegrability in composting conditions by means of visual, morphological, thermal, and chemical investigations was done to gain insights into the post-use degradation processes. Tensile test demonstrated the MCC reinforcing effect, while a bactericidal activity of silver-based composites against a Gram-negative bacteria (Escherichia coli) and a Gram-positive bacteria (Staphylococcus aureus) was detected at any time points and temperatures analyzed. Moreover, the disintegrability in composting showed that MCC is able to promote the degradation process. The combination of MCC and Ag nanoparticles in PLA polymer matrix offers promising perspectives to realize multifunctional ternary composites with good mechanical response and antibacterial effect, maintaining the optical transparency and the disintegrability, hence suitable for packaging applications. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124: [87][88][89][90][91][92][93][94][95][96][97][98] 2012

Characterization of PLA-limonene blends for food packaging applications

“…3-b the most relevant spectrum bands are identified. The typical asymmetric stretching of carbonyl group (C=O) by lactide is present at 1760 cm -1 [35]. The 1450 cm -1 band is assigned to the CH 3 group [22].…”

DEVELOPMENT OF ANTIBACTERIAL MtCu/PLA NANOCOMPOSITES BY CASTING METHOD FOR POTENTIAL USE IN FOOD PACKAGING

“…It has also been reported its use for laboratory containers with vegetables and bakery products, tea bags and water bottles, milk, yogurt, vegetable oil and fruit juices 17 . Despite the fact that their use is becoming increasingly popular, it can be limited to certain types of products, because some of the polymer properties need to be improved for specific applications, such as the high permeability to gases and vapors as well as poor mechanical and thermal properties 18 . Despite all the efforts made so far to improve the deficiencies of PLA, no results have been achieved which allows this type of polymers to replace traditional polymers (about their properties).…”

“…On the other hand, it is possible to observe that the elastic modulus obtained reaches higher values in MtCu 0 /PLA nanocomposites, which may be attributed not only to the clay presence but to the presence of copper nanoparticles located outside of the montmorillonite structure. This is due to the presence of metal nanoparticles in materials such as PLA, tends to increase the modulus 18 , thus the increase of tensile modulus in the MtCu 0 /PLA nanocomposites is produced by a synergistic effect of both free metallic copper nanoparticles and the clay structure. Therefore, a significant decrease was observed of elongation at break when MtCu 2+ was added in comparison to PLA.…”

Application of Poly(hydroxyalkanoate) In Food Packaging: Improvements by Nanotechnology

“…Incorporation of plasticizers for reduction of stiffness leads to a decrease in oxygen barrier and transparency. PLA, when compared to PET and polyolefins, presents easy processability 14 , availability in the market and transparency 15 , as well as printability 16 , biodegradability in compost 17 , but low thermal resistance, excessive rigidity, and high permeable properties. Conversely, the use of PLA films for food packaging has been strongly limited due to poor mechanical and barrier properties 18 .…”

“…The property improvement is in direct correlation with increased nanofiller dispersion. Cellulose nanocrystal (CNC) is an ideal biodegradable and biobased nanoparticle 107 which showed suitable mechanical properties, high stiffness, biodegradability, low density 17 and availability in nature with low cost 108 . A novel combination of PLA-PHB blends and functionalized CNCs showed a new perspective for their industrial application as food packaging in short-term 11 .…”