In this study, a carboxy esterification reaction was used to graft the hydrophilic polymers polyethylene glycol (PEG) and polyvinyl alcohol (PVA) onto the surface of carbon fibers (CFs). The properties of the grafted CFs were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TG) and through the measurement of interlaminar shear strength (ILSS). SEM enabled the graft morphology on CF surfaces to be determined. In comparisons of grafted and non‐grafted CFs, AFM indicated that the roughness was significantly improved; XPS showed that the concentration of oxygen‐containing functional groups increased by 186.1%; TG showed that the grafting rate of CF‐grafted PEG (CF‐g‐PEG) was 0.5%, and that of CF‐grafted PVA (CF‐g‐PVA) was 2.0%; and the ILSS of CF‐g‐PEG and CF‐g‐PVA increased by 22.7% and 43.0%, respectively. We conclude that esterification grafting is an effective method for modifying the physicochemical properties of CFs and improving the interfacial adhesion of composites. POLYM. ENG. SCI., 59:1043–1050, 2019. © 2019 Society of Plastics Engineers
Front-fed parabolic reflectors are among the most commonly used antennas in the industry. While in spaceborne applications, membrane reflectors are very promising due to their lightweight and foldable features. However, considering the large size, small thickness and low stiffness, solar radiation and microwave radiation will have considerable influences on the antennas' shape accuracy as well as the radiation characteristics. In this article, a theoretical approach is presented to solve the multi-physical effects of the parabolic antenna. The deformation of the reflector is derived by the shallow shell theory, taking into account the solar pressure, the microwave pressure and the thermal effects due to solar and microwave heating. The far-field electromagnetic radiation pattern is then obtained by considering the deformation of the reflector. On the other hand, a numerical approach combining the finite element method, the multi-level fast multipole method, and the large element physical optics is also presented. Numerical examples suggest good agreement between the theoretical and numerical results. The methods have been applied into the analysis of design models in the Space Solar Power Station project. Also, these approaches can be directly extended into other space membrane reflector antennas.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
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