Review of Thermodynamic Models in Polymer Solutions

[中文文摘］预测聚合物溶液体系的气液平衡数据是热力学模型的一个重要内容。热力学模型大体可分 3类 ,以过量吉布斯自由GF 能表示的最为常用。本文选取基于GF 的Flory Huggins(FH)、UNIQUAC、UNIFAC和ENSIC 4种常用模型进行评述 ,认为FH模型出现较早 ,形式最简单 ;UNIQUAC模型发展较完善 ,应用范围较广 ,UNIFAC模型弥补了UNIQUAC模型参数缺乏的不足 ,应用最为广泛 ;ENSIC模型具有较好的预测效果 ,但参数难以获得。［英文文摘］The equilibrium data of solvent|polymer systems are important to industrial processes, while they are very difficult to be obtained directly because of the complexity of the systems. It appears to be vital to obtain the data of solvent-polymer systems accurately by establishing thermodynamic models. This work presents a review of the four important thermodynamic models, e.g., UNIFAC, UNIQUAC, Flory-Huggins (FH) and ENSIC. Generally, they all can be used to predict the phase equilibrium of polymer-solvent systems. Of those , UNIFAC model is used most often , FH model　is the simplest, ENISC model is showed to be the most accurate and UNIQUAC model is seemed to be applicable to most　of the systems.国家自然科学基金 (No .5 0 2 4 30 14 ); 教育部留学回国人员科研启动基金资助项目

Preparation of Alginate-starch Blend Microspheres for Controlled Release of Berberine Hydrochloride

作者简介: 江宇良( 1985) , 男(汉族) , 江西樟树人, 现为厦门大学生物化 工专业在读硕士研究生, 主要从事生物材料研究工作.[中文文摘]目的应用天然药用高分子材料海藻酸钠和淀粉制备复合微球并研究其对盐酸小檗碱的控制释放性能。方法采用改进的乳化凝胶法制备复合微球,用光学显微镜观察了微球的形态,共聚焦激光扫描显微镜观察了药物的分布情况,紫外分光光度计测定了药物包封率,并测定了药物在不同介质中的释放。结果微球形态圆整,分散性好,包封率可达到80%以上,对盐酸小檗碱具有一定的缓控释效果。结论以海藻酸钠和淀粉为原料制备了性能良好的复合微球。 [英文文摘]Objective To prepare blend microspheres natural polymers alginate and starch and to study their controlled release performance on berberine hydrochloride.Methods A modified emulsification/gelation method was applied to prepare blend microspheres.Shape of those microspheres was observed with optical microscope.Drug distribution inside the Microspheres was observed with CLSM.Encapsulation efficiency was determined by UV-spectrophotometer.Drug release performance in two medium was also tested.Results Microspheres appeared to be spher ica l and w ell d ispersed in w ater. Encapsu lation effic iency was higher than 80%. M icrospheres was found to have a certa in effect on the contro lled release of berber ine hydroch lo ride. Conclusion B lend m icrospheres w ith good perfo rmancew ere prepa red w ith a lg ina te and starch国家自然科学基金(No.50573063)，教育部新世纪优秀人才计划项目(No.NCET-05-0566)，高等学校博士点专项基金(No.2005038401

Vapor-Liquid Equilibrium of 1-butanol-Alkanes System by Molecular Simulation

用Gibbs系综的Monte Carlo法模拟了正丁醇。正己烷和正丁醇-正庚烷体系的气液相平衡。在恒定压力0.496 6 MPa、0.294 0 MPa和0.1 MPa下,分别采用恒温恒压的Gibbs系综(NPT-Gibbs)模拟了不同温度下的气液相平衡。计算结果表明,模拟的数据比较准确,在一定温度范围内与实验结果吻合。The Vapor-Liquid equilibrium of 1-butanol/hexane and 1-butanol/heptane was measured by using Gibbs ensemble.The equilibrium data were obtained by the N-PT-Gibbs at the pressures of 0.4966 MPa,0.2940 MPa and 0.1 MPa.Comparing to the experimental data,the simulation results were quite good in some temperature range.国家自然科学基金(50573063);; 高等学校博士点专项基金(20050384013

Study on Exergy Analysis of Mine Air-conditioner Using Ice Slurry for Latent Heat Transportation

针对冰浆潜热输送矿井空调系统进行了设计，提出存在峰谷电价下的井上、井下设计方案。以淮南某矿井为例，根据冰浆潜热输送深井空调功能特性，将系统分为一次侧循环系统和二次侧循环系统，采用系统火用平衡分析法，代替传统的能量平衡分析法，得出了冰浆潜热矿井空调系统的火用损失分布

Review of thermodynamic models in polymer solutions

The equilibrium data of solvent-polymer systems are important to industrial processes, while they are very difficult to be obtained directly because of the complexity of the systems. It appears to be vital to obtain the data of solvent-polymer systems accurately by establishing thermodynamic models. This work presents a review of the four important thermodynamic models, e.g., UNIFAC, UNIQUAC, Flory-Huggins (FH) and ENSIC. Generally, they all can be used to predict the phase equilibrium of polymer-solvent systems. Of those, UNIFAC model is used most often, FH model is the simplest, ENISC model is showed to be the most accurate and UNIQUAC model is seemed to be applicable to most of the systems

Preparation of Chitosan Magnetic Microspheres

用共沉淀法制备Fe3O4磁性纳米粒子,并对其用油酸进行表面改性,继而采用沉淀聚合法制备壳聚糖磁性微球。考察了沉淀剂浓度、乳化剂种类、Fe3O4的改性等条件对制备微球的影响。应用扫描电镜、红外谱图、接触角仪、粒径分析仪及磁铁吸附对壳聚糖磁性微球的形态与特性进行了表征。研究结果表明,在适宜的沉淀剂浓度、复合乳化剂、Fe3O4经油酸改性等条件下,可以制得平均粒径为150 nm、单分散性好且磁性明显的壳聚糖磁性微球。The Fe3O4 nanoparticles were prepared by co-precipitation method and modified by oleic acid.Chitosan magnetic microspheres were then prepared by precipitation polymerization method.The results demonstrated that the concentration of the precipitant,the type of emulsion and the modification of the iron oxide were the most effective parameters for the preparation of the microspheres.The SEM,IR and DLS results indicated that the diameter of the microspheres was about 150nm and the microspheres were uniformly distributed.The magnetic test showed the microspheres were magnetic sensitive.国家自然科学基金(50573063);; 教育部新世纪优秀人才计划项目;; 高等学校博士点专项基金(2005038401);; 厦门大学人才基金(0000X071C1

A new activity model for polymer-solvent systems

A new molar excess Gibbs energy (G~ E ) expression for the correlation of vapor-liquid phase behavior for polymer solutions was developed from the Gibbs-Helmholtz relation, and a new activity model for polymer solutions based on the G~ E expression was then derived by accounting for the free volume effect.The model includes a combinatorial part, a residual part and also a free volume part.The calculated results by the present method were compared with those from the EFV,UFV and UNIFAC models.The average absolute deviation of solvent activities in 14 polymer solutions was 8141% for EFV , 7174 % for UFV, 19105% for UNIFAC and 3152% for the present model1 It is shown that the present model yields improved results over the other models and is able to describe the phase behavior for some polymer solutions over a wide range of concent ration.国家自然科学基金项目(50573063);高等学校博士点专项基金(20050384013)

Simulation of synthesis of phenol through the decomposition of cumene hydroperoxide by catalytic distillation

强酸性大孔树脂催化过氧化氢异丙苯(CHP)分解反应制苯酚是一个快速反应,需要用丙酮对进料CHP进行稀释,且反应过程要注意及时移出热量。依据该反应特点,设计催化精馏分解CHP制苯酚,应用Aspen Plus过程模拟软件进行了模拟计算。操作压力增大转化率下降而热负荷增大;回流比增大转化率开始增大,但一定程度后处于恒定;CHP进料位置越低转化率越低;而丙酮进料位置对转化率影响很小;停留时间增加,转化率开始增加而后维持一恒定值,但再沸器热负荷降低。计算结果对催化精馏分解CHP制苯酚工艺设计具有参考价值。The synthesis of phenol by the decomposition of cumene hydroperoxide(CHP) over a solid acid catalyst was studied.The rate of the reaction is very fast,so the CHP feed must be diluted with acetone to retard the reaction.A decomposition process of CHP by catalytic distillation was proposed based on the characteristics of the reaction,and Aspen Plus was used to simulate the process.It shows that phenol yield decreases and heat duty increases with the increase of operating pressure.The yield increases and reaches a constant value with the increase of reflux ratio.The lower the CHP feed stage is,the lower the yield will be;however,the acetone feed location plays a slight effect on the yield.The yield increases and then keeps constant with the increase of the resident time.The simulation results can be used as practical guidelines.厦门市科技计划资助项目(3502Z20055012

化工基础教学中学生工程观念的培养初探

结合自己在教学中如何培养学生工程观念的若干体会,探讨如何在具体事例中引导学生分析和解决工程问题。以提高学生学习本课程的积极性,最终掌握化工基础的基本内容

Molecular simulation of transport behavior of penetrant through silicon-containing polymers

选择PCFF和COMPASS分子力场对橡胶态聚合物PDMS和玻璃态聚合物PS1体系进行模拟。COMPASS力场模拟得到的体系密度,O2和N2在PDMS与PS1中扩散系数更接近实验值。在模型大小一定时,Group-based求和法中截断距离越长,耗用机时越长,但对计算结果改进不大;截断距离为1.3nm时计算结果最好。Ewald方法耗时多而对计算结果却无明显改进。体系大小对扩散系数的计算值影响甚微。体积越小的分子,在聚合物中运动的范围越大,扩散系数越大。氧气和氮气分子在PDMS与PS1中运动轨迹不同,在PS1中氧气运动范围远大于氮气,而在PDMS中氧气运动范围稍大于氮气。小分子运动轨迹基本与聚合物自由体积分布对应,自由体积分数大,扩散系数也大。PCFF and COMPASS force fields were used to describe PDMS and PS1 polymeric systems and to estimate the diffusion coefficient of N2 and O2 through the PDMS and PS1 matrices at 298 K by molecular dynamics simulation.It was found that the COMPASS force field was better in describing the transport behavior of the penetrants.The calculated densities after refinement were in good agreement with the experimental results.The group-based and Ewald summation skills were used to estimate the non-bonded interaction between atoms.Calculation using the Ewald summation method took much longer time without bringing in obvious improvement in density estimation.Various cut-offs in using the group-based summation method did not produce densities with much difference, and the cut-off of 1.3 nm was the best.Two types of diffusions of the small molecules in the polymers were discussed.The diffusion of O2 and N2 in PDMS could be transformed from anomalous to normal motion in 30 ps; while their diffusion in PS1 would take 300 ps transforming from anomalous to normal state.The trajectories of diffusion of N2 and O2 in PDMS or PS1 were different.The motion area of O2 in the PS1 was much larger than N2; however, the former in the PDMS matrix was only slightly larger than the latter.The diffusions of O2 and N2 in the PDMS and PS1 were consistent with the free volumes of polymers.国家自然科学基金项目(50573063);; 高等学校博士点专项基金项目(20050384013)。~