拉伸热历史对取向聚对苯二甲酸乙二酯膜在热处理过程中收缩和伸长的影响

弄清取向非晶态聚合物在热处理过程中的收缩和伸长的变化规律,以及所对应的结构变化,有较大的实用意义和科学意义。 对于取向聚对苯二甲酸乙二酯的热收缩和热伸长已有很多研究,但对于拉伸热历史对取向PET在热处理过程中的尺寸变化的影响尚缺乏系统的研究。在热拉伸的过程中发生分子链的取向、热弛豫和结晶三个相互竞争的过程。因此,改变拉伸条件可以得到具有各种不同取向和结晶的PET试样。当非晶态PET膜片在80-105℃以较低     

抗生育植物栀子花化学成分的研究：Ⅱ.栀子花甲酸的结构

我们已报道从栀子(Gardenia jasminoidesEllis)花的乙酸乙酯提取物中分得一种对大鼠有明显抗早孕作用的新三萜酸——栀子花乙酸(1),本文继续报道从该提取物中分得的另一种新三萜酸——栀子花甲酸(Gardenolicacid A,以下简称甲酸,2)的结构。 2为白色针状结晶,m.p.212～214℃,Liebermann-Burchard试验阳性,[α]_D~(17) 38.3,C_(30)H(46)O_(4),属三萜类。     

流动注射在线共沉淀HG-AFS测定痕量铅

建立了流动注射在线共沉淀HG-AFS测定痕量铅的分析方法。方法基于铅在碱性介质中与氢氧化镁共沉淀，沉淀收集在锥形沉淀腔中，用HCl溶洗沉淀和NaBH4反应，产生的氢化物被载气引入原子化器中进行测定。测定铅的RSD为3％(5ng/mL，n=10)，检出限为0．01ng。检出限较直接进样降低了11倍。对国家标准物质中铅的测定结果与标准值相符。     

基于差示扫描量热技术的生物质热解两步连续反应模型研究

采用差示扫描量热分析仪对我国的一种生物质试样在空气气氛中进行了实验, 发现试样从常温到923 K高温的低速升温过程中, 经历了两步明显的放热过程. 对放热机理的分析表明, 第一步主要是由半纤维素和纤维素的有氧热解过程控制, 第二步放热过程则受木质素热解和炭的氧化反应的共同作用. 采用等转化率方法和优化计算方法, 对热解过程的动力学模型进行了研究, 结果表明, 两步连续反应机理可用于描述生物质在空气气氛中热解的放热动力学.     

Novel Method of Preparation of Monolithic Columns for Fast Separation by γ-Ray Irradiation

A porous monolithic sol-gel column with the solution of methacryloxypropyltrimethoxysilane in toluene with an acid catalyst was prepared in the presence and absence of sodium dodecyl sulfate. In situ polymerization was carried out byγ-ray irradiation within the capillary. Theγ-radiation-initiated synthesis could generate radicals directly on the monomer avoiding use of any initiator. The chromatographic behavior of the capillary monolithic columns were studied in the modes of CEC, p-CEC and low pressure-driven separation, all the tests exhibited reversed-phase character. It provided a viable alternative to either thermally initiated or photo polymerization method for the preparation of monolithic columns.     

批量离子交换层析和凝胶过滤层析在类人胶原蛋白I纯化中的应用

研究了利用批量离子交换层析与凝胶过滤层析相结合的方法纯化类人胶原蛋白I的最佳条件。分别考察了不同离子交换树脂、缓冲溶液pH、离子强度、进料蛋白浓度对批量离子交换的影响,以及不同凝胶过滤介质对凝胶过滤层析的影响。结果表明,采用阴离子交换树脂DEAE52吸附杂蛋白,缓冲液pH为7.0,NaCl浓度为0.2mol/L,进料蛋白浓度为40mg/mL,并采用凝胶过滤介质SephadexG-100进一步纯化后,类人胶原蛋白I的纯度可达到98.2%,总纯化倍数为3.1,总回收率为80.6%。SDS-PAGE分子量分析和N末端氨基酸序列分析均表明纯化后的类人胶原蛋白I与基因设计一致。     

大区域取向对非晶态聚对苯二甲酸乙二酯结晶的影响

ffects of the chain orientation in the global sense on the solvent induced crystallization (SINC),diffusion velocity of toluol into poly(ethylene terephtlialate)(PET)and crystallization morphology were:studied by using density measurement and SEM.It has been shown that the SINC and diffusion velocity of toluol into PET increase with increasing degree of chain orientation in global sense,and the chain orientatioll can be essentially remained during SINC.     

主链含膦酸酯的聚酸酐药物控制释放材料研究

通过二氯膦甲（乙）酸乙酯与对羟乙氧基苯甲酸反应，制备了二羧苯氧乙氧基膦甲（乙）酸乙酯，并其转化成混合醋酐并通过熔融缩聚，合成了主链含膦甲（乙）酸乙酯的聚酸酐，以二羧苯氧乙氧基膦甲（乙）酸乙酯，分别与１，３－双（４－羧基苯氧基）丙烷（ＣＰＰ）及癸二酸（ＳＡ）共聚，得到相应的共聚酸酐，对所合成的单体和聚合物的结构进行了表征，研究了它们的体外降解，酶促降解及其对抗肿瘤药物５－氟尿嘧啶和氨甲喋蛉的释放性能     

PREPARATION OF PARTICLE SIZE NARROWLY DISTRIBUTED LOW-DENSITY STYRENE DIVINYLBENZENE COPOLYMER MICROBEADS

In view of the importance of dispersion agent, the amount of the crosslinking monomer andthe diluent in suspension polymerization for the production of particle size narrowly distributedIow-density styrene divinylbenzene copolymer microbeads (LDPS), their actions are preliminarilyinvestigated in this paper. Experimental results indicate that when both the gelatine and polyvinylalcohol (PVA) are used as dispersion agents, the better effect is achieved. DVB is helpful to theformation of the lower density fine particles, the proportion of the DVB/St should be between1:1～1.5:1. Compared with toluene, gasoline is the more effective diluent for the above target.     

Zr柱撑蒙脱土上负载稀土铈及铜铈催化剂的制备与表征

The Zr-pillaraed montmorillonite supported Ce and Cu-Ce catalysts were prepared by impregnation method. The performance of the catalysts was evaluated via the catalytic oxidation of volatile organic compounds (acetone, ethyl acetate, and toluene). The results showed that after supporting with Ce and Cu-Ce, the catalysts had a better reducibility. Moreover, the surface areas of the samples were increased. In addition，it was found that the Zr-pillared montmorillonite supported Cu-Ce catalysts had a higher activity and the reaction temperature decreased by 150～200 ℃ compared with the sample without Cu-Ce modification.