劈裂率对定向结构麦秸板物理力学性能的影响

通过比较4种不同劈裂率（100%、90%、70%、50%）的原料压制定向结构麦秸板，探究劈裂率对板材主要物理力学性能的影响。结果表明:随着劈裂率的降低，平行向的抗弯强度与抗弯弹性模量呈增大趋势，当劈裂率为50%，平行向的抗弯强度为59.38 MPa，比劈裂率100%时（51.75 MPa）提高了15%；平行向的抗弯弹性模量为6.65 GPa，比劈裂率100%时（5.40 GPa）提高了23%。垂直方向的抗弯强度与抗弯强度模量差异不显著。劈裂率100%、90%、70%间内结合强度差异不显著，劈裂率为50%时，内结合强度显著下降，50%劈裂率时的内结合强度为0.31 MPa，比劈裂率100%时（0.36 MPa）下降了14%。随着劈裂率的降低，2 h吸水厚度膨胀率和24 h吸水厚度膨胀率呈增大趋势，24 h吸水率差异不显著。劈裂率50%时的2 h吸水厚度膨胀率为5.46%，约为劈裂率100%时（1.80%）的3倍，24 h吸水厚度膨胀率为17.97%，为劈裂率100%（10.83%）的1.7倍。

Effects of Splitting Rate on the Physicomechanical Properties of Oriented Structural Straw Board

Oriented structural straw boards were prepared by using wheat straws with four (100%, 90%, 70%, and 50%) different splitting rates (SR) to examine the SR on physicomechanical properties of the board. The results demonstrated that with the decrease of SR, parallel-aligned bending strength (PBS) and bending modulus (PBM) tended to increase. For example, when SR was 50%, PBS was 59.38 Mpa, 15% higher than that of 100% SR, the PBM was 6.65 Mpa, 23% higher than that of 100% SR. The bending strength and bending modulus in vertical direction were not significantly different among different splitting rates. The differences in internal bonding strength (IBS) among the splitting rates of 100%, 90%, and 70% were not significant. However, with 50% SR, IBS significantly decreased. For example, IBS was 0.31 Mpa with 50% SR, 14% lower than that of 100% SR. Two-hour and 24 h thickness swelling rates (TSR) increased along with the decrease of SR, and the differences in 24 h TSR among different SRs were not significant. For example, with 50% SR, 2 h TSR was 5.46%, 3 times higher than that of 100% SR, and 24 h TSR was 17.97%, 1.7 times higher than that of 100% SR.