为了提高聚氨酯(PU)合成革透湿性,分别使用343 nm飞秒激光和作为对比的1030 nm飞秒激光及1064 nm纳秒激光制备微孔阵列.采用扫描电镜 (SEM)和3D激光扫描显微镜对比研究了微孔形貌.结果表明,343 nm飞秒激光可以制备出效果最佳的微孔.此外,分析了3种激光与 PU 涂层的作用机理,揭示了343 nm飞秒激光合成革微钻孔过程仅表现为光化学烧蚀,光化学和光热烧蚀同时发生于1030 nm飞秒激光钻孔过程,而1064 nm纳秒激光只显示了光热烧蚀.激光合成革表面钻孔后,测量其透湿性和抗张力.结果显示:微孔密度越大,皮革透湿性(WVP)越大而抗张力越低,脉冲重叠的增加会导致 WVP 的增加和抗张力的下降;同时,随着脉冲重叠从91.7%降到50%,微孔直径从45 μm 降低到30 μm,而微孔锥度从0.7°增加到12. 1°;当脉冲重叠率为91.7%,微孔密度为2550/cm2时,最大的 WVP增长率为306%.%In this paper,343 nm femtosecond laser and as a comparison,1030 nm femtosecond and 1064 nm nanosecond la-sers were used for improving water vapor permeability (WVP)of polyurethane (PU)synthetic leather.The morphologies of mi-cro-hole were comparatively studied via a scanning electron microscope (SEM)and a 3D laser scanning microscope.The results indicated that 343 nm femtosecond laser was optimal to obtain excellent and small drilled micro through-holes.Moreover,analysis of interaction mechanism between laser beam and PU film revealed that the micro-drilling by 343 nm femtosecond laser exhibited photochemical ablation only,micro-drilling by 1030 nm femtosecond laser caused both photochemical and photothermal ablation, while micro-holes drilled by 1064 nm nanosecond laser resulted in photothermal ablation.By measuring the WVP and tensile re-sistance of the laser-drilled leather,it was concluded that the higher micro-hole density,the higher WVP value and lower tensile resistance,and the increase of pulse overlap led to an increase of WVP and a decrease of tensile resistance.The diameter of micro-hole decreased from 45 μm to 30 μm and taper of micro-hole increased from 0.7°to 12.1°with pulse overlap decreased from 91.7% to 50%.And,the highest WVP growth ratio was 306% at 2550 per sq.cm and the pulse overlap was 91.7%.
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