Water-induced structural changes in poly(lactic acid) and PLLA-clay nanocomposites

Polymer ◽  
2016 ◽  
Vol 107 ◽  
pp. 211-222 ◽  
Author(s):  
F.R. Beltrán ◽  
M.U. de la Orden ◽  
V. Lorenzo ◽  
E. Pérez ◽  
M.L. Cerrada ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Structural Changes ◽  
Poly Lactic Acid ◽  
Clay Nanocomposites

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

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1095 ◽  
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.

Unusual mechanical properties of melt-blended poly(lactic acid) (PLA)/clay nanocomposites

2014 ◽  
Vol 52 ◽  
pp. 193-206 ◽  
Author(s):  
Sun-Mou Lai ◽  
Sheng-Huang Wu ◽  
Gwo-Geng Lin ◽  
Trong-Ming Don
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Poly Lactic Acid ◽  
Clay Nanocomposites

scholarly journals Analysis of Gas Permeability Characteristics of Poly(Lactic Acid)/Poly(Butylene Succinate) Nanocomposites

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Amita Bhatia ◽  
Rahul K. Gupta ◽  
Sati N. Bhattacharya ◽  
Hyoung Jin Choi
Keyword(s):  
Lactic Acid ◽  
Gas Permeability ◽  
Average Particle Size ◽  
Barrier Property ◽  
Morphological Properties ◽  
Poly Lactic Acid ◽  
Clay Nanocomposites ◽  
Average Particle ◽  
Butylene Succinate ◽  
Morphological Studies

Gas permeability and morphological properties of nanocomposites prepared by the mixing of poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and clay was investigated. While the composition of PLA and PBS polymers was fixed as 80% and 20% by weight, respectively, for all the nanocomposites, clay contents varied from 1 to 10 wt%. From the morphological studies using both wide angle X-ray diffraction and transmission electron microscopy, the nanocomposite having 1 wt% of clay was considered to have a mixed morphology of intercalated and delaminated structure, while some clusters or agglomerated particles were detected for nanocomposites having 3 and more than 3 wt% of clay content. However, the average particle size of the dispersed PBS phase was reduced significantly from 7 μm to 30–40 nm with the addition of clay in the blend. The oxygen barrier property was improved significantly as compared to the water vapor. A model based on gas barrier property was used for the validation of the oxygen relative permeabilities of PLA/PBS/clay nanocomposites. PLA/PBS/clay nanocomposites validated the Bharadwaj model up to 3 wt% of clay contents only, while for nanocomposites of higher clay contents the Bharadwaj model was invalid due to the clusters and agglomerates formed.

Enzymatic degradation of coconut shell powder–reinforced polylactic acid biocomposites

2018 ◽  
Vol 33 (6) ◽  
pp. 800-816 ◽  
Author(s):  
Faisal Amri Tanjung ◽  
Yalun Arifin ◽  
Salmah Husseinsyah
Keyword(s):  
Lactic Acid ◽  
Structural Changes ◽  
Enzyme Hydrolysis ◽  
Coconut Shell ◽  
Poly Lactic Acid ◽  
Infrared Analysis ◽  
Scanning Electron Micrographs ◽  
Scanning Calorimetry ◽  
Chemical Treatments ◽  
Polymer Chain Alignment

This work examined the effects of filler content and chemical treatment on the biodegradation of poly(lactic acid) (PLA)/coconut shell (CS) biocomposites in a diastase enzyme-containing buffer medium. CS was treated with two distinct chemical treatments: maleic acid and silanation with 3-aminopropyltriethoxysilane (3-APE). The CS was incorporated into PLA composites and their biodegradation patterns were studied. Both of the treated PLA/CS biocomposites exhibited lower biodegradation rates than the untreated biocomposites due to their enhanced interfacial adhesion, which reduced the area exposed to enzyme hydrolysis. Scanning electron micrographs taken after 30 days of biodegradation displayed surface roughening on both of the treated biocomposites, with fewer voids compared to the untreated biocomposites. The differential scanning calorimetry indicated that the glass transition temperature and melting temperature values of the treated biocomposites increased but that crystallinity declined. The crystallization temperature peak apparently disappeared due to the polymer chain alignment and rearrangement of the shorter PLA chains caused by the degradation. Fourier transform infrared analysis revealed the structural changes in the biocomposites after biodegradation, indicating the presence of soluble lactic acid as was confirmed by ultraviolet–visible spectroscopy analysis.

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