【作者】 王海燕； 伦照荣； 吕树申；

【Author】 Wang Haiyan,Lun Zhaorong,Lv Shushen School of Chemistry and Chemical Engineering,Sun Yat-sen University,Guangzhou,510275,China

【机构】 中山大学化学与化学工程学院；

【摘要】 在生物材料的冷冻干燥过程中,预冻是非常重要的阶段,它不仅影响形成冰晶的大小和形状,而且影响后续的升华速率和最终干燥产品的质量。本文研制了一种冷冻干燥装置,并在其中引入了DSC热分析与显微观察的功能。利用此连用DSC与显微方法的冷冻干燥系统,对低温保护剂海藻糖/聚乙烯醇(TR/PVA)水溶液进行了冷冻干燥实验,主要考察冷冻速率和冷冻溶液用量等不同冷冻条件对溶液冻结特性和升华过程的影响,并通过冻干溶液多孔结构的显微照片估计溶液冻结后形成冰晶的情况。结果表明,加快冷冻速率会导致不完全冷冻并形成大量细小冰晶,增加样品用量同样会引起过冷度增大,导致冰晶尺寸减小,使升华阻力增大,升华速率减慢。更多还原

【Abstract】 In biomaterials freeze-drying processes,the pre-ffeezing is an important step since it determines not only the ice crystals size and morphology in the frozen material but also the subsequent sublimation process,as well the final biological activity of the freeze-dried material.In the present study,a vacuum freeze-drying device was built and combined with differential scanning calorimetry(DSC) and microscopy,namely hereafter the freeze-drying system coupled by DSC and microscopy.By using the freeze-drying system coupled by DSC and microscopy,the freeze-drying experiments were carried out on a cryoprotectant aqueous 10%(g/g) trehalose solution supplemented with 1%(g/g) polyvinyl alcohol in order to investigate the effects of freezing condition,especially freezing rate and filling volume of the solution,on the freezing behavior of the solution and its subsquent sublimation.The mean ice crystals size after the pre-freezing step was estimated by the microphotos of the freeze-dried solution.The results showed that the ice crystals size depends not only on the cooling rate but also on the filling volume of the solution.Fast cooling rate results in partial freezing and small ice crystals.And the large filling volume results also in a large supercooing and small ice crystals size,by the way the increase of sublimation resistances and decrease of sublimation efficiency.更多还原