The Effects of Boric Acid on Fiberboard Properties Made from Wood/Secondary Fiber Mixtures: Part 4. Insulation Properties of Boards

The boards made from wood and secondary fibers appear to be well correlated secondary fiber/wood fiber proportions in terms of the behavior of the sound acoustic properties. However, boards were generally shown better acoustic (sound absorption) properties in high frequencies. Moreover, at middle level frequencies and lower boric acid addition (5.0%), the boards made from equal proportion of wood and secondary Old Corrugated Containers (OCC) and newspaper fibers shows markedly improved acoustic properties.

However, the boric acid addition had only marginal effects on relative thermal resistance values either improve or increase thermal properties, vice versa. It was observed that both the secondary fiber ratio contributes to the control of the relative thermal resistance values, and that under certain experimental conditions thermal resistance value of as low as 0.140 W/mK can be achieved.

It was also found that increasing boric acid content positively impacts on the boards degradation that decomposition temperature was increased for boards in all boric acid conditions. This is an important result considering boric acid affects improving board’s thermal resistance some level. Moreover, the endothermic peaks at 71°C, 266°C and 333°C for Differential Scanning Calorimetry (DSC) have clearly consisted with Thermogravimetric Analysis (TGA) curves.