Haider M. Umran , Hasan F. Alesary , Hani K. Ismail , Feipeng Wang , Stephen Barton
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引用次数: 0
Abstract
Modern power electronic systems require appropriate metallized polypropylene capacitors (MPCs) to operate in harsh environments. Due to their limited operating capabilities, commercial biaxially-oriented polypropylene (BOPP) films—the primary component of MPCs—are susceptible to degradation in high electric fields and at high temperatures. In order to enhance the aging behavior of BOPP, this work proposes one-sided phosphorylation at optimum and excessive acid concentrations of 8 % and 15 % for 24 hours at a [high] temperature of 60 °C. The proposed surface modifications' success in enhancing the aging behaviors of BOPP is confirmed by DC electrothermal aging. Field emission scanning electron microscopy (FE-SEM) analysis reveals changes in surface morphology resulting from phosphorylation. The changes in crystal structure of the original and phosphorylated samples are evaluated using X-ray diffraction (XRD). The average crystallite size, dislocation density, and microstrain during aging are also characterized using the Williamson-Hall (W-H) analysis method. Fourier transform infrared (FTIR) spectroscopy is used to identify changes in the chemical composition and functional groups resulting from phosphorylation and aging, while X-ray photoelectron spectroscopy (XPS) is used to analyze changes in the surface chemical elements of the original, phosphorylated, and aged samples. The charge-thermally stimulated discharge (C-TSD) technique and broadband dielectric spectroscopy (BDS) are used to verify the electrical performance. Mechanical properties, including thermal stability, are measured using the dynamic mechanical analysis (DMA) technique. The results indicated that the optimized phosphorylation improved the BOPP film's electrical and mechanical properties. As a result, the surface charge stability was found to increase under thermally stimulated discharge by 74 % and the dielectric constant by 2 %, while the dielectric losses decreased by 20.2 %. Under aging, for the first time, the dielectric constant was found to increase by 4.8 %, while dielectric losses decreased by 8.9 %. In return, deformation resistance, ductility, and lower energy dissipation demonstrated enhanced mechanical performance.
期刊介绍:
Polymer Degradation and Stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology.
Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies. In more specialised applications, degradation may be induced by high energy radiation, ozone, atmospheric pollutants, mechanical stress, biological action, hydrolysis and many other influences. The mechanisms of these reactions and stabilisation processes must be understood if the technology and application of polymers are to continue to advance. The reporting of investigations of this kind is therefore a major function of this journal.
However there are also new developments in polymer technology in which degradation processes find positive applications. For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry. Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.