Optical properties of Poly Vinyl Alcohol (PVA)/molasses as biodegradable films for agriculture applications

Abstract

Biodegradable polymeric films were prepared for agricultural applications. These films based on PVA/ molasses blend mixed with different concentrations (0, 10, 20, 30 and 40 wt. %). These films were characterized by FTIR spectrometer, while UV-Visible technique used to study the molasses effects on the absorption, transmission and reflection properties. Films roughness and their morphologies were studied by AFM technique, while hardness test utilized as a function of the mechanical performance. Thermal IR camera was used to monitor the thermal effects due exposing the prepared film to sun light for 1 minute. Results showed that there is no chemical interaction between film components. The hardness increased generally, and the film contains 20% molasses shows the higher hardness. The absorption of PVA/molasses films increased with increasing molasses content in UV regain by 260%, in visible region by 1788% and in the infrared (IR) region by 647%. The transmittance decreased linearly with the molasses content by the following order: IR > Visible > UV, while reflectance increased from 64.2% to 96.09% in UV region, from 19.76% to 90.8% in visible region and from 15.8% to 72.17% in IR region. As molasses content increased, the film morphology converted from continuous/discontinuous phase to the co-continuous phase domains and the surface roughness increased generally. IR camera results showed significant effects after sun light exposing; there are clear fluctuations in temperature distribution, and the film contains 10% molasses exhibited maximum temperatures.