Zainab A Ali, Alaa Karem Niamah and Widad Salih Hannosh
الملخص العربي
Lactic acid was isolated by using microbial fermentation in whey media which was
carried out by local strain Lactobacillus paraplantarum then polymerized using the acidic
medium's polycondensation method. FTIR and H-NMR were used to characterize the isolated
lactic acid monomer and polyalctic acid (PLA), and the results confirmed the chemical structures
of the isolated lactic acid and PLA. GPC techniques were used to determine the molecular weight
and molecular weight distribution of the prepared PLA; the result showed that the Polydispersity
index (PDI) was 2.51. The Biodegradable composite films of poly lactic acid (PLA)/Nano silica
powder were prepared by the composite film casting method using dichloromethane as solvent.
In contrast, Nano silica was synthesis from hydrolysis of tetra ethoxysilane and was loaded in
PLA in 1 to5 wt. %. The films were subjected to a tensile strength study. Thermogravimetric
analysis (TGA) and differential thermal analysis (DSC) were used to evaluate PLA. Also, water
absorption of the prepared composites was studied, and the result showed that the thermal
stability and water absorption of these prepared films were increased with an increasing
percentage of Nano silica, while the percentage of crystallinity of the PLA evaluated from DSC
was 28 %.
علاء كريم نعيمة | Alaa Kareem Niamah | 5645