Abstract
Biodegradable polymer nanocomposites have received great attention due to their synergistic properties of good mechanical and barrier properties; yet, they are biodegradable. In this research, prior to compression into thin sheets, polylactic acid (PLA), tapioca starch, glycerol and maleic anhydride (MA) were compounded with different loadings of montmorillonite (MMT) through a twin screw extruder. MMT was added to improve the mechanical and barrier properties of PLA/starch blend. The effects of MMT loadings on tensile property, morphology and biodegradability were studied. X-Ray diffraction analysis showed that samples with MMT loadings below 6 phr exhibited exfoliated structure, while samples that contained MMT above 6 phr (5.66 wt%) exhibited intercalated structure. The exfoliated-type structure was observed using transmission electron microscopy. These effects were manifested in the tensile results, which showed an increase in modulus, tensile strength and elongation at break. However, for the modulus, the MMT content was limited to 4 phr (3.85 wt%). Beyond that, the modulus decreased. It was thought that above 4 phr, the MMT particles agglomerated, thus reducing the modulus of the samples. This argument was supported by field emission scanning electron microscopic images, which showed big lump when MMT loadings were at 6 and 8 phr (7.41 wt%). Meanwhile, the addition of MMT has improved the water barrier property and hastened the rate of biodegradation. The nanosized MMT particles disturb the continuity of PLA/starch chain, which formed pathways for microorganisms to enter and attack the chain, thus increasing the biodegradation rate. The particle is also able to block a tortuous pathway for water to enter the starch chain, thus reducing the water uptake and improving the physical barrier of nanocomposite.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.