聚苯乙烯—二乙烯基苯共聚物树脂的溶胀干燥动力学

研究了聚苯乙－二乙烯基苯交联树脂为作为空气清闲缓释基材在不同条件下燥过程。发现交联树脂具有明显的缓释作用，香料挥发量以指数函数的     

壳聚糖/改性凹土复合树脂的制备及其缓释性能研究

以壳聚糖和改性凹土为原料,采用氢氧化钠固化,戊二醛交联的方法制备了壳聚糖/改性凹土复合树脂微球,分别采用FT-IR和TG对树脂进行结构表征。以阿司匹林为模型药物,考察了树脂的缓释性能,并对最优条件下树脂释放药物的曲线进行了动力学模型拟合。研究结果表明,CS/O-ATP树脂的吸附性能和缓释性能最佳,当戊二醛的加入量为6mL时,其载药量和包封率分别为12.2%和39.88%,且缓释效果较好。CS/O-ATP树脂的药物释放规律复合Higuchi方程,表明该树脂可以作为长效药物的缓释载体。     

高吸油树脂缓释动力学研究

以丙烯酸系高吸油树脂缓释过程为研究对象，以α-甲基丙烯酸十二酯为主单体，研究了引发剂，交联剂用量及溶剂溶度参数对树脂缓释行为的影响，提出描述高吸油树脂作为缓释材料基材的缓释速率方程：t^1/2/Q=A kt，发现交联密度和溶剂溶度参数是更为根本的影响因素。     

几种氨基酸的拆分研究

以交联聚苯乙烯为原料树脂,二苯甲酰酒石酸酐为傅克酰基化反应的酰化试剂合成手性树脂拆分剂,用制备的手性树脂初步进行了DL-氨基酸的分离研究,该树脂拆分剂对几种氨基酸有明显的拆分作用.     

以萘为单体、三聚甲醛为交联剂的缩合多核芳香烃树脂的合成、交联及性能研究

以萘为单体、三聚甲醛为交联剂，可在对甲苯磺酸、浓硫酸或氯磺酸的催化下，在１５０～１６０℃下反应得到未交联的缩合多核芳香烃树脂（Ｂ－树脂）。这种Ｂ－树脂不能单靠热交联的方式转化为Ｃ－树脂，但如果在交联时添加２０％～３０％（质量）的交联剂，则Ｂ－树脂即可有效地进行交联，交联后树脂在氮气中的热降解起始温度在５００℃左右。     

以萘为单体,三聚甲醛为交联剂的缩合多核芳香烃树脂的合成,交…EI

以萘为单体、三聚甲醛为交联剂，可在对甲苯磺酸、浓硫酸或氯磺的催化下在１５０－１６０℃下反应和到未交联的缩合多核芳香烃树脂（Ｂ－树脂）、这种Ｂ－树脂不能单靠热交联的方式转化为Ｃ－树脂，但如果在交联时添加２０－３０％（质量）的的交联剂，则Ｂ－树脂即可有效地进行交联，交联后树脂氮气中的热降解起始温度在５００℃左右。     

聚丙烯酰二乙烯三胺二氧化碳吸附树脂的制备及性能

以丙烯酸甲酯和二乙烯基苯悬浮共聚,制备了交联度分别为5%、7%、9%的大孔交联聚丙烯酸甲酯(PMA),通过与二乙烯三胺的胺解反应得到了大孔交联聚丙烯酰二乙烯三胺(PAM)吸附树脂;通过红外光谱(FT-IR)对树脂的结构进行了表征;系统考察了静态吸附法下PAM树脂对CO2的吸附性能以及作为CO2吸附材料的循环使用性能。结果表明,在室温下交联度为5%的PAM树脂具有较高的CO2吸附量,达143.1 mg/g吸附剂,CO2吸附量随胺基数量增加而增大,且PAM树脂具有良好的循环使用稳定性。     

以三氧六环为交联剂的COPNA树脂的合成与性能研究

以三氧六环为交联剂，萘、萘酚、蒽及其混合物为单体，可在对甲苯磺酸或三氯乙醚催化下，在８０～１６０℃下反应得到未交联的缩合多核芳香烃树脂。对聚合反应机理作了一定的研究，并提出了聚合机理。以萘酚或萘为单体的树脂的交联较为困难，而在萘中加入蒽，不但可大大提高反应速率，也可使所得树脂的交联变得容易。交联后树脂在氮气中的热降解起始温度在４００℃左右。     

逆常规选择性阳离子交换树脂的合成及性能研究

聚苯乙烯氯球经Ｆｒｉｅｄｅｌ－Ｃｒａｆｔｓ后交联反应以后再磺化，合成一类具有较高交联度和较低交换容量的阳离子交换树脂。经测定其对Ａｇ＾＋及其它贱金属离子的交换性能，研究了树脂交换容量对其选择性的影响。结果表明该类树脂对Ａｇ＾＋的选择性明显高于普通阳树脂。     

改性酰化壳聚糖缓释肥包膜材料的制备与表征

壳聚糖与辛酰氯酰化反应,制备低取代度的酰化壳聚糖。通过元素分析计算酰化壳聚糖的取代度,并用红外光谱、核磁共振、尿素渗透测试对其结构及渗透性能进行分析和表征。以戊二醛为交联剂,制备了一系列酰化交联壳聚糖膜,用吸水倍率、接触角、X射线衍射仪、热重分析、尿素渗透等对其性能进行分析表征。结果表明,交联使酰化壳聚糖热稳定性提高;酰化交联壳聚糖缓释包膜材料结晶度下降,疏水性提高;随戊二醛含量增加,尿素累积渗透量下降,7 d内尿素累积渗透量由74.7%降低至34.2%,28 d时尿素累积渗透量为76.7%,改性酰化壳聚糖膜缓释性能良好。     

Investigation of the mechanism of radiative-convective drying of colloidal capillary-porous materials using radioactive tracers

Radioactive tracers have been used to study the process of layerwise drying of crumbled material. The dependence of evaporation zone penetration on the maximum drying rate has been established, and the phase composition of the transferred moisture has been determined.     

Structure reorganization in montmorillonite gels during drying

The structure evolution of montmorillonite gels, during drying by evaporation, has been studied by scanning electron microscopy (SEM) after hypercritical drying with liquid CO₂. Fresh Fe³⁺¹ electrolytes allow clay particles to aggregate to floes with a structure consistent with diffusion-limited aggregation. Compression under the capillary stresses, during evaporation, leads to gelation. During further drying by evaporation, the Fe bonding is strong and prevents the complete collapse of the gel into a parallel stacking of clay plates. On the contrary, such a collapse occurs more easily when fresh Fe electrolyte has not been added.     

Influence of humidity on the cracking patterns formed during the drying of sol-gel drops

Optical microscopy has been used to study the sequence of events associated with drying of a silica-based sol-gel. Drops of sol containing 50 wt% silica were deposited on glass slides and dried in cells containing sulphuric acid as a drying agent. The drops, on the slide, were about 3.5 mm in diameter and before the onset of drying had a spherical cap shape. At the start of drying the rim of the drops became pinned to the glass surface. The humidity of the drying environment had a strong effect on shrinkage within the drop and the processes that occurred during drying. In very dry environments evaporation occurred primarily from the edges of the drop and resulted in a radial concentration gradient in the gel. Shrinkage resulted in a pattern of radial cracks that spread from the outside in a direction orthogonal to the iso-concentration profiles. Cracking was preceded by shear deformation. Drying was more uniform in humid environments and occurred from both the rim and the top surface of the drop. Wrinkling of the skin of gel that formed on the surface of the drop was followed by radial and circumferential cracking, except in very humid environments. The results are attributed to the influence of the radius of curvature of the drop surface on the rate of evaporation and the relative rates of flow and diffusion in the drying sol-gel.     

挥发速率对胶体悬浮液干燥花样的影响

研究了不同挥发速率下厚度较薄的凹液层胶体悬浮液的干燥花样。Panasonic照相机用于拍摄宏观干燥花样。结果表明,随着挥发速率的减小,马兰哥尼对流强度下降,胶体悬浮液的干燥花样更为平整均匀。在较低的挥发速率下可避免宽环花样形成,制备得到表面平整的薄膜,反射光谱证明其可作为三维光子晶体材料。     

Predictive CFD modeling of whey protein denaturation in skim milk spray drying powder production

A new model of whey protein thermal inactivation has been combined with a CFD model developed for skim milk spray drying. Extensive evaporation and particle formation models were used to calculate particle moisture contents, temperatures and residence times. Calculated parameters were then used as input data for an experimentally developed quality model based on Williams-Landel-Ferry (WLF) equations for inactivation kinetics. The developed quality model was implemented into the CFD code and calculated in parallel to simulations of skim milk droplets evaporation based on the characteristic drying curve approach. The quality model and the simulation procedure were validated by comparison of protein activity levels obtained from the CFD with data obtained from differential scanning calorimetry (DSC) of milk powder samples collected during skim milk spray drying experiments. The simulations for different feed rates fit well with measurement results and show that the loss of whey protein activity is lower at higher feed rates, due to lower temperature fields in this case.     

苯乙烯改性醇酸树脂及快干醇酸漆的研制

以脂肪酸、季成四醇、苯酐和顺酐为原料合成基础醇酸树脂,通过比较几种不同的苯乙烯改性醇酸树脂方法,确定采用后苯乙烯化法的改性工艺路线,并对到树脂的合成及改性工艺条件进行了优化。检测结果表明,所得改性树脂具有颜色浅、快干、硬度高、综合性能较好等特点。     

Study of the drying process of wetted surfaces under conditions similar to food processing conditions

Two experiments were carried out inside a test room in order to study the drying rate of wetted surfaces under conditions similar to those encountered in food processing plants. In the first experiment, the evaporation of water droplets on a stainless steel plate representing typical equipment was studied under different ambient conditions in the room. In the second experiment, in order to reproduce drying conditions inside a food processing plant, the floor was entirely wetted with water, the water mass evolution was measured when the discharge air was dried by a dehumidifier, and the results were compared with those obtained without using a dehumidifier. Models predicting the evaporation rate in these two experiments were developed and the numerical results show good agreement with the experimental data. Relative humidity was the factor which exerted the greatest influence on the evaporation rate. The drying rate on the stainless steel plate increased five-fold when a dehumidifier was used.     

带辅助冷凝器的封闭式热泵干燥系统理论分析

介绍带辅助冷凝器的封闭式热泵干燥系统,采用控制变量法对系统中的变量（如干燥室进出口空气温度和湿度、冷凝温度、蒸发温度、过热度和过冷度等）进行调节,得到各变量对除湿能耗量（SMER）的影响。计算结果表明,不同的干燥室出口空气湿度均对应着最佳的空气旁通率使得除湿能耗量最大,增大干燥室进出口空气温度和湿度可增大系统的效率,提高过冷度和过热度也可使系统效率增大。     

Quantitative investigation of particle formation of a model pharmaceutical formulation using single droplet evaporation experiments and X-ray tomography

The implementation of a particle design platform that can be applied to novel pharmaceutical systems using acoustic levitation (SAL) and X-ray tomography (XRT) is discussed. Acoustic levitation was employed to provide a container-less particle design environment for single droplet evaporation experiments. Dried particles were subject to further visual and quantitative structural analysis using X-ray tomography to assess the three-dimensional volume space. The workflow of the combined SAL-XRT platform has been applied to investigate the impact of increasing HPMC K100LV concentrations on the evaporation, drying and final particle morphology of particles from a model pharmaceutical formulation containing metformin and D-mannitol. The morphology and internal structure of the formulated particles after drying are dominated by a crystalline core of D-mannitol partially suppressed with increasing HPMC K100LV additions. The final structure can be correlated to the observed evaporation kinetics. The characterisation of formulated metformin hydrochloride particles with increasing polymer content demonstrated the importance of an early-stage quantitative assessment of formulation-related particle properties. The ability to study the evolution of solid phase formation and its influence on the final particle morphology can enable the selection of formulation and process parameter that deliver the desired particle structure and consequent performance by design.     

The influence of different drying conditions on powder properties and processing characteristics

A water-based suspension of submicron titania particles was dried using a variety of techniques. The resulting powders were fully characterized in order to observe the effect of drying conditions on particle agglomeration. Direct evaporation methods led to quite severe agglomeration, whilst removal of the water by a freeze-drying technique produced powders containing only weak-secondary clusters.

The consequences of the state of aggregation after drying on powder compaction, sintering rates and microstructural development were determined. Although all powders originated from a common starting suspension, samples isolated by freeze drying sintered most rapidly, reaching about 98% of the theoretical density after firing at 1150 °C for 2 h. Agglomerated powders obtained after drying by evaporation, using either a heat lamp or microwave oven to drive off the water, required twice as long to sinter to comparable density. Moreover there was evidence of a much finer-grained microstructure in ceramics fabricated from freeze-dried products.