杨木真空镀膜处理后的表面特性

Surface properties of poplar wood after vacuum coating

通过在杨木表面沉积派拉伦薄膜来提高杨木的防水性能，研究中采用真空蒸发的镀膜方式将派拉伦薄膜沉积在杨木表面，通过扫描电镜、接触角测量仪等现代分析仪器研究经过镀膜处理后的杨木表面微观形貌变化和润湿性变化，并通过24 h浸水试验研究杨木的防水能力。处理工艺为：蒸发温度92～97℃，裂解温度680℃，沉积室真空度0．1 Pa，沉积室温度25 ℃，蒸镀时间5 h。试验结果表明，派拉伦薄膜成功沉积在杨木表面，并可以形成较完整的膜层，但其在杨木横切面与纵切面表面的沉积状态有所不同；镀膜处理后试件的接触角明显增大；24 h吸水率以及24 h体积膨胀率下降幅度分别为35．9％和20．2％，14 d平衡处理后，杨木的24 h吸水率下降幅度为82．5％，24 h体积膨胀率下降幅度为56．3％。

Parylene film is mainly used for water treatment in the electronics industry, and is rarely used to treat woodsurface. In this study, Parylene film with excellent waterproof and moisture-proof performance was introduced to improvethe dimensional stability of poplar wood by means of vacuum deposition. The Parylene powder was evaporated at 92-97℃ and cracked at 680 ℃. The sanded samples to be coated were hung in a deposition chamber with a pressure and tem-perature of 0.1 Pa and 25 ℃, respectively, and the depositing time was 5 h. Scanning electron microscopy and contactangle measurement were applied to study the morphology and wettability of the coated samples. The waterproof perform-ance of the samples was also studied by 24 h immersion experiment. The results showed that Parylene film was depositedon the wood surface successfully and formed a fiat and smooth surface. However, significant deposition difference wasfound between transverse section and longitudinal section of the samples, which may attribute to the structural differencesbetween the two sections. The deposited film exhibited poor continuity in transverse section. After the vacuum deposition,the contact angle of the samples increased; the 24 h water absorption and 24 h volume swelling dropped by 35.9% and20. 2%, respectively. After 14 days＇ conditioning, the 24 h water absorption of poplar wood decreased by 82. 5%, andthe 24 h volume swelling decreased by 56.3%. Based on the experimental results, Parylene film in wood surface coatingwas feasible to improve the waterproof performance, but further research is need to get better waterproof performance.