采用6%浓度氨水浸泡后与10%、20%、30%、40%、50%浓度尿素溶液蒸煮（95℃）的方法对有竹节和无竹节毛竹（Phyllostachys heterocycla cv. pubescens）材进行软化处理，展平试验及XRD和FTIR分析，结果表明：竹材的展平裂缝数均随着尿素浓度的增加而减少，当尿素浓度较低时，竹节的有无对裂缝数的影响不大，当尿素浓度较高时，无节竹材展平裂缝数明显小于有节竹材的裂缝数；竹筒曲率半径随着尿素溶液浓度的增大而增大，当尿素浓度较低时，有无竹节对竹材曲率半径变化率的影响不大，当尿素浓度在较高时，无节竹材的曲率半径变化率明显高于有节试件的曲率半径变化率；XRD分析表明，试件相对结晶度随尿素浓度增加而增大的原因是由于试件蒸煮处理的过程中试件中的抽出物的溶出，非结晶区内纤维素微纤丝的表面活性得到表现。另外在蒸煮过程中木质素的玻璃化转变温度降低，导致木质素部分降解；FTIR分析结果表明，随尿素浓度增加竹材表面羟基（-OH）数量显著增加，结晶度逐渐增大，最高时可达59.91%，竹材表面裂缝数逐渐减少。%Experiments were conducted on softening of Phyllostachys heterocycla cv. pubescens culm with pretreatment of dipping in 6%ammonia, and followed by 10%, 20%, 30%, 40%and 50%urea at 95℃ for 4 hours. The result demonstrated that cracks of flattened samples decreased with increase of urea concentration. It had no evident influence of internode on cracks when urea concentration was low, but when concentration increased, cracks of flattened samples without internode were fewer than that with internode. Radius of curvature had positive relation with concentration of urea. It had no evident influence of internode on radius of curvature when urea concentration was low, but when concentration increased, radius of curvature of flattened samples without internode had higher variation. Analysis by FTIR and XRD showed that softening properties of bamboo improved with higher concentrations of urea, because of the number of surface hydroxyl(-OH)and crystallinity of the samples increased gradually, even topped to 59.91%.
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