Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

Chern Chiet Eng,Hidayah Ariffin,Wan Md Zin Wan Yunus,Nor Azowa Ibrahim,Cher Chean Teh,Yoon Yee Then,Norhazlin Zainuddin

doi:10.1155/2013/816503

Abstract

The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA)/Polycaprolactone (PCL) blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two Tg of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology.

Highlights

Petroleum-based polymers such as polypropylene (PP), polyethylene (PE), and polystyrene (PS) cause major drawback to environment as these polymers tend to accumulate in disposal system due to these polymers are nondegradable
The incorporation of hydrophilic clay Nanomer PGV successfully enhance mechanical properties of Polylactic acid (PLA)/PCL blends and makes it become more flexible while the addition of clay Montmorillonite K10 makes PLA/PCL blends become stiffer
X-Ray Diffraction (XRD) results show that the addition of Nanomer PGV increase of the basal spacing of the composites compared to the corresponding neat clay which implies that the PLA/PCL chains might be intercalated into the clay matrix after mixing but there is no clear evidence from Transmission Electron Microscopy (TEM) micrographs to support the formation of intercalated types of nanocomposites

Summary

Introduction

Petroleum-based polymers such as polypropylene (PP), polyethylene (PE), and polystyrene (PS) cause major drawback to environment as these polymers tend to accumulate in disposal system due to these polymers are nondegradable. A wide range of natural or synthetic polymers degrade by hydrolytic (polyglycolide, polylactides, polydioxanone, Polycaprolactone, polyhydroxyalkanoates) or enzymatic (polysaccharides, protein, polyamino acids) route [1]. These polymers have wide range of mechanical properties and degradation rate, inappropriate stiffness or degradation rate restrict their application, blending with other polymers, copolymerization or adding plasticizer can be used to tune the properties of these polymers according to application requirements [2]. Indian Journal of Materials Science modification of PLA is needed in order to compete with other flexible polymers such as polypropylene or polyethylene [4]. There are many techniques to modify PLA such as copolymerization [5, 6], blending with other polymers [7, 8], the addition of plasticizers [9], the addition of nucleating agents [10], and forming composites with fiber or nanoparticles [11, 12]

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