The Effects of Boric Acid on Fiberboard Made from Wood/Secondary Fiber Mixtures: Part 3. Utilization of Recycled Waste Office Paper Fibers

Abstract

It was discovered that an increase in the proportion of secondary fibers has a negative impact on strength and thickness swelling (TS) properties of experimental boards. However, the highest MOR value of 20.0 MPa was found for type 1 board (C1) produced with a 90/10 Wood/Seconder fiber (W/S) ratio. Likewise, the highest MOE value of 2119 MPa was obtained with the C4 (type1) board. A statistical analysis (ANOVA) clearly indicates that the variables, such as boric acid content and W/S proportions, significantly affect the mechanical properties and that it is indeed possible to produce boards with higher mechanical properties than standard values with an optimum proportion of wood/secondary fiber ratio and a particular boric acid content. It was found that increasing the secondary fiber proportion at some levels improved sound absorption properties of the boards somewhat. The highest mean value of 0.82 at 2500 Hz was achieved by using the C6 boards, while 0.78 at 2500Hz was obtained for C6a boards, where both types of boards were produced with a ratio (W/S) of 40/60. The lowest thermal conductivity (better insulation) was found to be 0.1729 W/mK in type1 boards that were made with 10/90 (W/S) fiber mixture (C9). It was learnt that boric acid supports heat resistance properties of those experimental boards manufactured from various proportions of W/S mixtures. Indeed, increasing boric acid content has a negative impact on thermal degradation, so that decomposition temperature had to be increased for type 2 boards. FTIR spectra for the two types of boards are not particularly different. Multi-modal absorption in the 1300-1350 cm-1 region was achieved by using boron containing groups.