醋酸酯淀粉的制备与初步表征

以淀粉为基料,以冰醋酸和醋酸酐为乙酰化试剂,以硫酸为催化剂,制备了醋酸酯淀粉;用红外光谱仪对醋酸酯淀粉进行了初步表征,并用酸碱滴定法测试了其取代度和乙酰基含量;系统讨论了反应温度和反应时间等对醋酸酯淀粉的取代度、乙酰基含量的影响.实验结果表明:随反应温度升高和反应时间延长,乙酰基含量和取代度增大;当反应温度为50℃,反应时间为6h,催化剂质量浓度为0.1%时,取代度和乙酰基含量较高.     

玉米淀粉醋酸酯的制备及成膜性能

以冰醋酸和醋酸酐为改性剂,浓硫酸作催化剂,合成了玉米淀粉醋酸酯,用傅立叶红外(FT-IR)、扫描电镜(SEM)、差示扫描量热法(DSC)、X射线衍射(XRD)分别对淀粉醋酸酯的结构、形貌、玻璃化转变温度和结晶度等进行测试和表征,分析了不同酯化度对淀粉的微观结构和热性能的影响。结果表明,淀粉经酯化后,结晶度降低,热性能提高,制备的酯化淀粉/聚乙烯醇的复合膜具有较好的力学性能和疏水性。     

玉米淀粉醋酸酯用于制造淀粉膜的研究

选用玉米淀粉醋酸酯，添加若干种增塑剂，以改进淀粉膜的伸长百分率，柔软性，为制取性能好的食用薄膜提供依据。     

马铃薯辛烯基琥珀酸淀粉酯的制备工艺研究

以马铃薯淀粉为原料,辛烯基琥珀酸酐为亲核试剂,水相法制备辛烯基琥珀酸淀粉酯,以取代度为衡量指标,利用单因素试验与正交试验结合方法对影响它的主要因素进行分析,得出结论。     

马铃薯辛烯基琥珀酸淀粉酯的制备工艺研究

以马铃薯淀粉为原料,辛烯基琥珀酸酐为亲核试剂,水相法制备辛烯基琥珀酸淀粉酯,以取代度为衡量指标,利用单因素试验与正交试验结合方法对影响它的主要因素进行分析,得出结论。     

氨基甲酸淀粉酯的改进合成及其性能研究

以氧化玉米淀粉作为原料,尿素为酯化剂,氯化铵为催化剂,制备了氨基甲酸淀粉酯。分别测定了氨基甲酸淀粉酯的红外光谱、氮含量及其对杨木板的胶合强度,并计算出氨基甲酸酯的取代度(DS)。与玉米淀粉为原料相比,产物DS及胶合强度均有所提高。研究结果表明反应的最佳条件为:mst∶mur∶mca=30∶5.0∶7.10,反应时间4h,反应温度140℃,氧化玉米淀粉羰基含量为0.42%时,氨基甲酸酯的取代度可达最大值0.285,胶合强度为1.044MPa。     

无载体淀粉胶粘剂的研制

论述了无载体淀粉胶粘剂的研制原理、方法及技术特点。并研究了在不同反应条件下的各种影响因素。指出无载体淀粉胶粘剂是一种各方面性能都较理想的、适于生产瓦楞纸板的新型淀粉胶粘剂。     

马来酸酐改性聚乙烯对玉米淀粉的修饰作用

通过干法工艺用马来酸酐改性聚乙烯(Zemac)修饰玉米淀粉,改变加碱量、Zemac用量及反应温度,探讨不同反应条件下产物的理化性质。结果表明,不同反应条件得到Zemac-starch取代度在0.0050~0.0113之间;红外光谱在波数为1700cm-1~1730 cm-1附近未检测到明显的羰基特征吸收峰,在波数为2850 cm-1~2900 cm-1附近的CH2对称振动峰有所增强;核磁共振氢谱中在δ0.7~3.0之间出现新的吸收峰,说明淀粉发生酯化反应。不同加碱量和Zemac加量对产物黏度有明显影响;随着反应温度升高,产物黏度有所上升,适当高温条件利于反应进行;偏光显微研究表明,随着Zemac-starch取代度的提高,淀粉颗粒的中心双折射性有所减弱,但产物结晶结构无明显变化。     

酯化淀粉制备工艺条件的研究

以玉米淀粉为原料,乙酸酐为酯化剂,乙酸为活化剂,浓硫酸为催化剂,对玉米淀粉进行酯化改性,制备了一定取代度的酯化淀粉.在考察单个反应条件对取代度影响的基础上设计了正交实验,研究了各反应条件的相互影响,确定了影响因素由大到小依次为:反应时间、催化剂浓硫酸的量、活化剂乙酸的量(乙酸和乙酸酐的体积比)、反应温度.其中影响最为显著的反应条件是反应时间.追加实验验证了正交实验的合理性,优化的淀粉酯化改性的工艺条件:反应温度75℃,反应时间1.5h,浓硫酸用量为0.13mL,活化剂乙酸用量(乙酸和乙酸酐的体积比)为0.7.此时取代度为0.45.     

马来酸酐改性聚乙烯对玉米淀粉的修饰作用EI北大核心CSCD

通过干法工艺用马来酸酐改性聚乙烯（Zemac）修饰玉米淀粉,改变加碱量、Zemac用量及反应温度,探讨不同反应条件下产物的理化性质。结果表明,不同反应条件得到Zemac-starch取代度在0.0050~0.0113之间;红外光谱在波数为1700cm-1~1730 cm-1附近未检测到明显的羰基特征吸收峰,在波数为2850 cm-1~2900 cm-1附近的CH2对称振动峰有所增强;核磁共振氢谱中在δ0.7~3.0之间出现新的吸收峰,说明淀粉发生酯化反应。不同加碱量和Zemac加量对产物黏度有明显影响;随着反应温度升高,产物黏度有所上升,适当高温条件利于反应进行;偏光显微研究表明,随着Zemac-starch取代度的提高,淀粉颗粒的中心双折射性有所减弱,但产物结晶结构无明显变化。     

可食性玉米淀粉膜成膜特性的研究

以玉米淀粉为原料,探讨在不同条件下的成膜特性.经试验在24cm×18cm的膜盒中以75ml去离子水溶解原料为最佳延流体积,当m(淀粉）:m(甘油)=4.2:1.0:0.25时,在85℃度烘干2h左右,可得到较为理想的玉米淀粉膜.     

Intravaginal Controlled Administration of Flurogestone Acetate: (III) Development of Rate-Control Vaginal Devices

A Rate-Control vaginal device was developed which overcomes the low bioavailability and unpredictable Q - t^1/2 type release and absorption rate profiles of flurogestone acetate delivered by the currently marketed Syncro-Mate pessary.

The in vitro release and vaginal absorption profiles from the Rate-Control vaginal device were run simultaneously, a linear Q - t relationship was obtained with a significant improvement in bioavailability. A mathematical model was developed to correlate the in vitro drug release and the vaginal absorption profiles of flurogestone acetate from the vaginal devices.

The design, development and the simultaneous release and absorption profiles of flurogestone acetate from this new vaginal device were outlined and discussed.     

Intravaginal Controlled Administration of Flurogestone Acetate: (III) Development of Rate-Control Vaginal Devices

Abstract

A Rate-Control vaginal device was developed which overcomes the low bioavailability and unpredictable Q – t^1/2 type release and absorption rate profiles of flurogestone acetate delivered by the currently marketed Syncro-Mate pessary.

The in vitro release and vaginal absorption profiles from the Rate-Control vaginal device were run simultaneously, a linear Q – t relationship was obtained with a significant improvement in bioavailability. A mathematical model was developed to correlate the in vitro drug release and the vaginal absorption profiles of flurogestone acetate from the vaginal devices.

The design, development and the simultaneous release and absorption profiles of flurogestone acetate from this new vaginal device were outlined and discussed.     

Hydrolysis of Cellulose Acetate and Cellulose Acetate Butyrate Pseudolatexes Prepared by a Solvent Evaporation-Microfluidization Method

Aqueous colloidal Cellulose acetate dispersions have recently been introduced as an alternative to organic polymer solutions for the coating of osmotically active cores with a semipermeable membrane. Cellulose esters are known to hydrolytically degrade in an aqueous environment. This study followed the chemical degradation of pseudolatexes of the cellulose esters, cellulose acetate and cellulose acetate butyrate, over time and as a function of temperature. The pseudolatexes were prepared by a microfluidization-solvent evaporation method. The hydrolysis of the cellulose esters was followed by determining the pH and the amount of the acidic degradation products, acetic and butyric acid, in the aqueous phase of the polymer dispersions with an HPLC assay. The degradation followed a pseudo first-order equation and rate constants and activation energies were calculated. In addition to chemical instability, agglomeration and gelling of the colloidal particles occurred. The pseudolatexes were stable at 4°C, however, if stored at higher temperatures, the preparation of a redispersible polymer powder is recommended.     

琼脂糖醋酸酯的制备方法与表征

以浓硫酸为催化剂,琼脂糖与醋酸酐反应制备出琼脂糖醋酸酯。研究了反应温度等参数对取代度的影响,结果表明,50℃时取代度最大。接触角测试结果表明,琼脂糖醋酸酯较琼脂糖接触角增大,疏水性明显增强。傅里叶变换红外光谱、核磁共振碳谱证实形成了琼脂糖醋酸酯。热重分析测试表明,琼脂糖醋酸酯具有不同于琼脂糖的热特性。琼脂糖醋酸酯可作为疏水性新型可纺丝材料,可望应用于组织工程支架。     

Interconversion Studies of Betamethasone Acetate Polymorphs

ABSTRACT

The polymorph interconversions of Betamethasone Acetate (BA) were studied under various pharmaceutical conditions, such as grinding, heating and suspending in water, based on differential scanning calorimetry, thermogravimetric analysis, and X-ray powder diffraction. There existed enantiotropic relationships between the three polymorphs of BA, which were named form II, Iα, and Iβ work, respectively. It was concluded that form II was the most stable form when suspended in water.     

Magnetic and Structural Properties of Ni/NiO Nanoparticles Prepared Using Nickel Acetate and Polyvinyl Acetate Precursor

Ni/NiO nanoparticles were synthesized using a mixture of nickel acetate and polyvinyl acetate as precursors, followed by heating between 350–450 °C. The prepared samples were investigated using XRD, TEM and SQUID magnetometry. Depending on the heating temperature, the average sizes of Ni and NiO crystallites were found to be in the ranges of 25–37 nm and 10–26 nm, respectively. The analysis of XRD patterns shows that the volume percentage of Ni can be easily controlled by the heating temperature. Magnetization measurements show that the samples consist of ferromagnetic moments which are blocked at low temperatures and a disordered NiO component which causes spin-glass like behavior.     

醋酸乙烯细乳液聚合动力学

用十二烷基硫酸钠(SDS)为乳化剂,十六醇(CA)为难溶助剂,以偶氮二异丁腈(AIBN)引发醋酸乙烯酯(VAc)进行细乳液聚合。在聚合体系中预先引入了聚合物,研究了聚合物、温度、引发剂浓度对细乳液转化率的影响,得出聚合物的引入可以显著加快聚合反应速率,聚合物用量宜控制在单体用量的2%,反应的表观活化能为38.6 kJ/mol,聚合速率与引发剂浓度的0.24次方成正比。     

聚乙烯蜡与醋酸乙烯酯的溶液接枝聚合

以过氧化二苯甲酰（BPO）为引发剂,苯为溶剂,进行了聚乙烯蜡（PEW）和醋酸乙烯酯（VA）的溶液接枝聚合。实验考察了反应温度,反应时间及BPO和VA用量对接枝率,转化率和接枝效率的影响,得到了接枝率0－19．8％的接枝物,粘度和凝点实验结果表明,接枝物在良溶剂甲苯（TOL）中的特性粘数[η]接枝率的增大而升高;接枝物的接枝率为13％－17％时对模拟油（4％大庆石蜡／甲苯和4％大庆石蜡／正已烷）的降凝效果最好。