Thermal Properties, Crystallinity, and Oxygen Permeability of Na-montmorillonite Reinforced Plasticized Poly(lactic acid) Film

Abstract

Introducing unmodified organically clay/Na-montmorillonite (Na-MMT) was applied into plasticized poly(lactic acid) PLA to produce film composites by direct casting. Film composite structure, the crystallinity degree and form, and thermal properties were carried out using X-ray diffraction and differential scanning calorimetry. The effect of Na-MMT to the tortuous path and the crystallinity degree in the plasticized film composites were calculated in oxygen barrier properties. Chromatogram film composites resulted in an intercalated structure that showed peak diffraction angle shift at about 0.2 o . Then, a peak diffraction pattern was indicated in α-form crystal structure. Plasticized PLA has a crystallinity degree at 34%, and the addition of Na-MMT increased to 52%. Glass transition temperature improved from 53 °C to 57 °C, and melting temperature remained stable at 167 °C. Filling Na-MMT into plasticized PLA caused to enhance a tortuous path about 28% and improved the oxygen permeability to 80%. As a result, the addition of Na-MMT of 3% into plasticized PLA during film composite preparation using the mixing method resulted in balancing properties related to the crystallinity degree, thermal properties, and oxygen barrier properties. AbstrakSifat Panas, Kristalinitas, dan Permeabilitas Oksigen Film Poly(lactic acid) Terplastisasi diperkuat Namontmorillonite. Pembuatan film komposit poly(lactic acid) terplastisasi PEG400 dengan bahan penguat Namonrmorillonite (NA-MMT) dilakukan dengan metode direct casting. Film komposit PLA terplastisasi dilakukan uji struktur komposit, sifat panas, derajat kristalinitas dan permeabilitas terhadap oksigen. Pengujian sifat panas dan penghitungan derajat kristal diperoleh dari pengukuran differential scanning calorimetry (DSC), analisis struktur komposit menggunakan xray diffraction (XRD) dan pengukuran permeabilitas oksigen menggunakan dynamic accumulation method. Film komposit PLA terplastisasi dengan bahan penguat Na-MMT menunjukkan terjadinya interkalasi polimer Na-MMT dengan pergeseran sudut difraksi sebesar 0.2 o . Stuktur kristal yang terbentuk memiliki bentuk alpha dan derajat kristal film komposit meningkat dari 34% menjadi 52%. Parameter sifat panas film PLA terplastisasi dengan bahan penguat Na-MMT mengalami perbaikan suhu transisi gelas dari 53 °C menjadi 57 °C meskipun suhu leleh tidak mengalami perubahan tetap bekisar pada nilai 167 °C. Peran Na-MMT membentuk jalur liku sebesar 20% sehingga terjadi peningkatan daya halang oksigen film komposit PLA terplastisasi yang ditunjukkan dengan penurunan nilai permeabilitas sebesar 80%. Penambahan Na-MMT sebesar 3% dalam pembuatan film komposit PLA terplastisasi cukup untuk mendapatkan keseimbangan perbaikan sifat panas, kristalisasi, dan daya halang oksigen.

Ascorbic Acid Degradation in Cut Lemon Packaged Using Oxygen Scavenging Active Film During Storage

“…Therefore, adding a larger fraction of BHT into the active film has a positive effect functioning as an oxygen barrier. We had confirmed in previous studies on oxygen permeability using both passive film and active film based on polylactic acid [21], [22]. Oxygen permeability coefficient decreased when the oxygen scavenging film was used but did not completely alleviate free oxygen diffusion, which implies that some oxygen will pass through the film and react with the packaged product such as a cut lemon.…”