Abstract
This study explored the crystallization and thermal properties of copolymers of polylactic acid–polyethylene glycol (Mn: 600) (PLLA–PEG 600 copolymer) nanocomposites with added montmorillonite (clay). The d-spacing of the hydrophilic montmorillonite was increased by using a quaternary ammonium salt. The salt was used to modify montmorillonite via ion exchange. The modified montmorillonite was then evenly dispersed in the matrix of the PLLA–PEG 600 copolymer to synthesize the nanoscale polymer via solution casting method. Thermogravimetric analysis and differential scanning calorimetry were used to measure the thermal properties of the PLLA–PEG 600 copolymers with various proportions of added clay. Wide-angle X-ray diffraction was used to identify the crystal structure and lattice displacements of PLLA–PEG 600 copolymer and the copolymer with added clay. Using polarized optical microscopy and transmission electron microscopy, the crystal growth and size of PLLA–PEG 600 copolymer with various proportions of added clay, as well as the dispersion of the clay, were observed. Adding clay to PLLA–PEG 600 copolymer improved its thermal properties and crystallinity without changing its original crystal structure.
GRAPHICAL ABSTRACT
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