Preparation and characterization of PLA composites with modified magnesium hydroxide obtained from seawater

Abstract

Modification of poly(lactic acid) (PLA) was performed with the surface modified magnesium hydroxide (mMH) obtained from seawater. Surface modification of MH with different amount of stearic acid (SA) results in chemically bonded SA, stearate as confirmed by Fourier transform infrared spectroscopy (FT-IR). Based on FT-IR and X-ray diffraction (XRD) analysis modified filler with a higher amount of SA was used for the composite preparation. PLA/m10MH composites were prepared using laboratory mixing extruder. Differential scanning calorimetry (DSC) was applied to study thermal properties and crystallinity of PLA/mMH composites, while the thermal stability was performed by thermogravimetric analysis (TG). According to DSC analysis, PLA crystallization is primary influenced by the filler. PLA/m10MH composites degrade in four degradation stages. With an increase of m10MH content in the composites, their thermal degradation becomes more complex and their thermal stability is getting worse. XRD and X-ray microcomputed tomography (XμCT), used to obtain structural and microstructural information about PLA/m10MH composites, revealed that addition of m10MH decreases the crystallinity of PLA, increases the porosity of the composite and produces agglomeration of mMH.