【摘要】 采用真空干燥获得玫瑰花瓣压花材料,研究真空度、温度等条件对玫瑰花瓣干燥特性、压花艺术美观性的影响,采用差热-热重(TG-DTG)分析、扫描电镜对玫瑰花瓣热变化过程、表面微观形态进行表征,建立干燥过程动力学模型并计算动力学参数。结果表明,温度越高,真空度越大,玫瑰花瓣的干燥越快,但温度过高,玫瑰花瓣的艺术美观性下降,在真空度0.1MPa、45℃、30 min下干燥,可以获得具有较好艺术美感的玫瑰花瓣压花材料。真空干燥下,玫瑰花瓣正面原阵列状的乳突结构和反面的沟回结构逐渐收缩,导致正面乳突腔体塌陷,反面形成浮雕状突起。干燥过程的有效扩散系数为8.119×10-9m2/s,活化能为10.045 k J/mol,动力学模型可用薄层干燥Wang and Singh模型来描述。更多还原

【Abstract】 The dehydration of rose petals in vacuum was dynamically modeled,analytically calculated and experimentally measured. The impact of the drying conditions,including but not limited to the temperature,pressure and drying time,on the microstructures and artistic quality of rose petals was investigated with scanning electron microscopy and thermal gravity analysis. The results show that the temperature and pressure strongly affect the vacuum drying. For example,a higher temperature and a lower pressure result in a faster drying rate; however,high temperature hurts the artistic beauty of rose petals as pressed flower materials. The optimized vacuum drying conditions include a temperature of 45℃,a pressure of 0. 01 MPa,and a drying time for 30 min. The vacuum drying can be best described by the thin layer drying model reported by Wang and Singh. The effective diffusion coefficient and activation energy were estimated to be 8. 119 × 10-9m2/ s and 10. 045 k J / mol,respectively.更多还原