Publication: Studies on the effect of uv exposure on the properties of poly (lactic acid) (pla)
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Date
2012-07-01
Authors
Yap, Hui Ping
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Abstract
Poly (lactic acid) (PLA) is a typical biodegradable polyester obtained by synthesis of lactic acid (or lactide), which can be produced from renewable resources such as corn or sugarcane. PLA is famous with biodegradability and good processability and expected to substitute some of the non-biodegradable plastics. However, due to its poor heat stability and brittleness, it limits the application. The purpose of this research is to study the effect of UV exposure on the properties of PLA. PLA 3051D Grades was extruded by extruder and then shaped into desired shape by using compression molding. Samples were exposed 2 to UV (0.68 mW/cm) using an accelerated weathering chamber for 0,100,200,300,400 and 500hours. Various testing was conduct to observe the effect of UV exposure on the samples. The testing consists of visual inspection, color change test tensile test, differential scanning calorimetry (DSC), gel permeation chromatography (GPC) and fourier transform infrared spectroscopy (FTIR). The results showed that the yield strength, modulus and elongation at break of PLA reduced when the UV exposure time increased. In addition, the glass transition temperature and melting temperature of PLA decreased while the degree of crystallinity of PLA increased with UV exposure time. Molecular structure of PLA was affected by UV exposure which could be seen from FTIR and GPC result.