Fig. 3

Mean modulus of rupture (MOR) and internal bond strength (IB) of particleboards subjected to various exposure conditions. 5-year high humidity, 5-year exposure to relative humidity of 90 % at 20 °C. 5-year cyclic humidity, 5-year exposure to cycles of relative humidity of 45 % at 20 °C for 3 months and 90 % at 20 °C for 3 months (one cycle is equal to 6 months). 1-, 3-, and 5-year outdoor, 1-, 3-, and 5-year outdoor exposure in Tsukuba, Japan, respectively. JIS Test B, accelerated aging test in compliance with Test B in JIS A 5908 [21] or JIS A 5905 [22] (boiling for 2 h and subsequent water soaking for 1 h at room temperature). Abbreviations are explained in Table 1. Error bars denote standard deviations