Effect of Ozone Aging on Electric Strength and Mechanical Properties of Polylactic Acid

Accompanied by the advocacy and proposal of green power, polylactic acid, as a new type of biodegradable material, is expected to become a key technology in the energy industry, and its application prospects in the power system are very broad. However, with the prolonged working operation of electric power equipment, corona discharge occurs in the air, and high concentration of ozone will have a certain impact on the performance of PLA. Therefore, this paper carried out a study on the impact of ozone aging on the bending strength and un-notched simply supported beam impact strength of polylactic acid. It was found that with the increase in the ozone ageing time, the bending strength and the impact strength of the notched simply supported beam of PLA show a trend of first decreasing and increasing later. After aging, the bending strength of the sample reached 87.23 MPa, which was 17.42% lower than that of the unaged sample; The minimum impact strength of the un-notched simply supported beam is 35.19 kJ/m
²
, which is 15.22% lower than that of the unaged sample. Through the analysis of FTIR and DSC experimental results, it was found that after ozone aging treatment, the - OH in the molecular structure of PLA increased, and the C=O and C-O-C functional groups decreased, which led to the decrease of the degree of polymerization of PLA materials, and the overall mechanical strength showed a downward trend. However, at the beginning of aging, certain temperature and ozone conditions caused the increase of the crystallinity of PLA materials, resulting in a temporary increase of mechanical properties. This study aims to provide a certain experimental basis for the practical application of PLA in the operation of complex power grids.