(217aq) Sucrose Ester/ Poly(lactic acid) Nanocomposites for Food Packaging Application: Fabrication and Characterization

Polymers are significantly used in food packaging applications including storage and transportation of food as it is low cost material and can be process economically at industrial scale.¹ Further, due to environmental and sustainability issues related to petroleum-based polymers, a growing emphasis is given to explore novel eco-friendly polymeric materials with atleast comparable barrier and mechanical properties without compromising it’s adverse effect on human health. In the current scenario, polylactide (PLA) is considered to be the potential representative of degradable and bioderived polymers to replace the conventional fossil-based polymers such as poly (ethylene terephthalate), Poly (styrene), Poly (propylene), etc ². PLA can be used for some of the packaging applications where moderate mechanical, thermal and barrier properties are required.² However,PLA has its own limitations such as higher permeability, brittleness and lower crystallinity.³ To alleviate these limitations, current research work is focuses on development of sucrose ester reinforced poly(lactic acid) composites (PLA-SuE) and its properties investigations in order to address above limitations. Sucrose ester as filler is used in the current studies aiming its application in food packaging as such fillers are approved as food contact material by U. S.  Food and Drug Administration (FDA).⁴

We have fabricated PLA composites by dispersing various loading of sucrose ester into polymer matrix through solution casting approach. Various characterization techniques have been conducted to investigate the influence of the biofiller on morphological, thermal, mechanical and rheological behavior of PLA composites. Derivative weight loss curves obtained from thermo gravimetric analyses of PLA composites and neat PLA exhibited a single peak indicating that degradation of these materials proceeded in one step. No change in the temperature for maximum rate of degradation (357ºC) was observed for neat PLA and its composites up to 5 weight percentage of sucrose ester loading. Spherulite morphology of PLA-SuE are examined through polarized optical microscopy equipped with hot stage. Increase in nucleation density of spherulites having smaller radius are observed for PLA-SuE in comparison with neat PLA because of nucleating ability of biofiller. This phenomenon is well corroborated with enhancement in crystallinity of PLA-SuE composites revealed by differential scanning calorimetry and X-ray diffraction analysis. Fourier transform infrared spectroscopy results elucidated the existence of hydrogen bonding and intermolecular interaction between PLA and reinforcement. The dispersion state of sucrose ester in the PLA composites was directly visualized using field-emission scanning electron microscopy (FE-SEM).  Nanoindentation studies indicated that the incorporated filler is effective in enhancing the young’s modulus of PLA due to the reinforcing ability of the novel filler. Therefore, the use of bio-derived sources for both polymer matrices and reinforcement material may provide solution towards sustainable development of ecologically attractive structural composite technology.   

AUTHOR INFORMATION

*Corresponding authors.

Email: pugal@iitg.ernet.in & vkatiyar@iitg.ernet.in

References

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