紫外辐照提升聚丙烯的介电储能密度研究

Dielectric Energy Storage Density of Polypropylene Improved by Ultraviolet Irradiation

双轴拉伸聚丙烯(BOPP)薄膜因其低的介电损耗和高的击穿强度等优点被用作电容器的电介质材料,但介电储能密度相对较低限制了其广泛的应用。因此采用紫外辐照对BOPP进行改性,对紫外辐照前后的试样进行介电性能测试,结果表明随着紫外辐照时间的增加,BOPP的介电常数和储能密度呈明显上升的趋势,介电损耗仍然保持在较低水平。经过紫外辐照48 h后,介电常数由2.21增加到2.98,储能密度由2.10 J/cm^3提升到2.85 J/cm^3。采用红外光谱表征BOPP薄膜的分子结构,结果表明紫外辐照使薄膜内部生成了羰基。

Biaxial-oriented polypropylene( BOPP) films were used as dielectric materials for capacitors because of their low dielectric loss and high breakdown strength,but the relatively low dielectric energy density limits their large-scale applications.Therefore,UV irradiation were used to modify BOPP,and their dielectric properties were characterized. The experimental results show that the dielectric constant and energy storage density of irradiated BOPP increase with the increasing of irradiation time,and dielectric losss still keep a lower level. After 48 hours of irradiation,the dielectric constant increases from 2.21 to 2.98,and the energy storage density increases from 2.10 J/cm^3 to 2.85 J/cm^3. Infrared spectroscopy shows the carbonyl is formed inside the BOPP films under UV irradiation.