Preparation and characterization of nano‐filled polypropylene dielectric films

Modified copper calcium titanate (MCCTO) or functional activated carbon (FANC) particles were added to functional polypropylene (FPP) or heat‐treated polypropylene (HTFPP) matrix to improve the performance of FPP as dielectric films. By testing and characterizing the prepared FPPwxMCCTOy, FPPwxFANCz, FPPwxMCCTOyFANCz and HTFPPwxMCCTOy, HTFPPwxFANCy and HTFPPwxMCCTOyFANCz films, It is found that the dielectric constant and discharge energy density of each FPPwxMCCTOy, FPPwxFANCz, HTFPPwxFANCz and HTFPPwxFANCz films reach the maximum when the MCCTO and FANC loads are close to 8 and 6 wt% respectively. FPPwxMCCTO8FANCz and HTFPPwxMCCTO8FANCz series films also obtain the maximum dielectric constant and discharge energy density at FANC load approaching 6 wt%. The discharge energy density of HTFPPw86MCCTO8FANC6 film prepared properly is 3.2 J/cm3, which is more than 3 times higher than that of FPP. When MCCTO and FANC loads are ≦8 and 6 wt% respectively, with the increase of additive content, More dense distribution of MCCTO and FANC was observed in FPPwxMCCTOy(or HTFPPwxMCCTOy), FPPwxFANCz(or HTFPPwxFANCz) and FPPwxMCCTO8FANCz(or HTFPPwxMCCTO8FANCz) series film sections. In this paper, we propose possible explanations for the apparent improvement in dielectric constant, discharge energy density and heat resistance of capacitive films after appropriate heat treatment or addition of appropriate MCCTO and/or FANC loads.