Study on the suitability of bamboo fiber for manufacturing insulating presspaper

Because bamboo grows faster, responds more rapidly to beating, and has a lower cost than softwood, we pay great attention to the abundant bamboo material to alleviate the severe shortage of softwood resources in China. For this purpose, bamboo fiber, softwood fiber, and their blend were used to prepare presspaper samples via a laboratory papermaking platform. Differences between bamboo fiber and softwood fiber were evaluated by optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Performances of softwood presspaper were taken as a reference. Mechanical results show that tensile strength of presspaper can be reinforced by introduction of bamboo fibers with a concentration ranging from 10 wt. % to 50 wt. %. Volume resistivity and dielectric behavior of presspaper made from bamboo fibers or blended fibers are comparable with or even better than those of softwood presspaper. Electrical breakdown strengths of presspaper and oil-impregnated presspaper decrease significantly when bamboo fiber content approaches 50 wt. %. Although thermal stability of bamboo presspaper is slightly inferior to that of softwood presspaper. Presspaper containing 10 wt. % bamboo fibers has a thermal-endurance similar to softwood presspaper. It is suggested that the available bamboo fiber without special treatments is not quite suitable for manufacturing insulating presspaper. However, the usage of bamboo fiber in combination with softwood fiber is promising, especially when bamboo fiber content is around 10 wt. %.