Plasma Surface Functionalization of Biaxially Oriented Polypropylene Films with Trimethyl Borate

The radiofrequency plasma (13.56 MHz) was employed to polymerize trimethyl borate (TMB) monomer/N2 gas mixture on the surface of biaxially oriented polypropylene (BOPP) films. Plasma polymer coated polypropylene films were examined by flame retardancy test (limiting oxygen index, LOI). The highest LOI value calculated for the untreated BOPP sample was 18.4 (v/v O2%) and 24.2 (v/v O2%) for the 55 W 30 minutes treated sample. The plasma polymers were characterized by FTIR spectroscopy and AFM. According to the FTIR results, the -OH, B-CH3, B-O, and BH2 functional groups were detected. It was found that the highest surface roughness belonged to 40 W 30 min treated BOPP sample which was calculated as 9.78 nm (10 μm × 10 μm). Moreover, the wettability of the modified BOPP film surfaces was characterized via contact angle measurements. The water contact angle values have decreased from 109.6? to the lowest value of 68.2? after the plasma treatment. The results showed that TMB/N2 plasma modification could be used as an alternative method for the enhancement of flame retardancy and hydrophilicity of BOPP film.

基于介质阻挡大气压空气均匀放电的聚丙稀薄等离子体表面处理(英文)

The homogeneous dielectric barrier discharge(DBD) in atmospheric air is most favorable for polymer surface modification due to the low cost of operation and the ability of ambient on-line continuous uniform processing.In this paper,polypropylene(PP) films are treated using a homogeneous DBD plasma in atmospheric air.The surface properties of PP films are studied using contact angle and surface energy measurement,scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy(FTIR),and the aging effect after treatment when the treated materials are exposed to open air is also studied,with the modification mechanism being discussed.It is demonstrated that non-thermal plasmas generated by homogeneous DBD in atmospheric air is an effective way to enhance the surface properties of PP films.After the plasma treatment,the surface of PP film is etched,and oxygen-containing polar groups are introduced into the surface.These two processes can induce a remarkable decrease in water contact angle and a remarkable increase in surface energy,and the surface properties of PP films are improved accordingly.

Reliability Analysis of Grid-Interfaced Filter Capacitors

Growing with the increased adoption of renewable energy for the power generation,the reliable and cost-effective operation of grid-connected inverters is of more and more importance.A filter is interfaced between an inverter and the utility grid to reduce the switching harmonics.According to the modulation scheme and the LCL filter impedance,the electrical stresses of the filter capacitor can be thoroughly investigated.With the help of the electro-thermal model,its long-term thermal stress can be obtained based on the mission profile like wind speed,ambient temperature.The reliability of the filter capacitor bank is obtained based on its individual capacitor reliability curves and reliability block diagram method.A case study on a 2MW wind turbine system demonstrates the relationship between the lifetime of the capacitor bank and the single capacitor.Moreover,the severe voltage and current stresses of the filter capacitors are analyzed during abnormal operations(e.g.,fault ride-through)with asymmetrical parasitic parameters.