温度及pH敏感聚(丙烯酸)/聚(N-异丙基丙烯酰胺)互穿聚合物网络水凝胶的合成及性能研究

合成聚（丙烯酸）／聚（Ｎ 异丙基丙烯酰胺）互穿聚合物网络（ＰＡＡｃ／ＰＮＩＰＡＩＰＮ）水凝胶，具有温度及ｐＨ双重敏感特性．这种水凝胶在弱碱性条件下的溶胀率远大于酸性条件下的溶胀率．在酸性条件下，随着温度上升，凝胶的溶胀率也随之逐渐上升；而在弱碱性条件下，温度低于聚（Ｎ 异丙基丙烯酰胺）（ＰＮＩＰＡ）的较低临界溶解温度（ＬＣＳＴ）时，溶胀率也随着温度的上升而上升，当温度达到ＬＣＳＴ时，凝胶的溶胀率突然急剧下降，并随着温度的逐渐上升而下降．     

激光光散射研究聚(N-异丙基丙烯酰胺)单链及其智能凝胶微球在水中的相变(下)

（接上期）２聚（Ｎ－异丙基丙烯酰胺）微凝胶在水中的体积相变２．１理论部分凝胶体积相变热力学：聚合物凝胶的溶胀和蜷缩可以用膨胀因子α＝（Ｖ／Ｖ０）１／３＝（ΦＴ／ΦΘ）１／３来表征，其中ΦΘ的ΦＴ分别是温度Θ和Ｔ下凝胶网络的体积分数。在平均场理论中，中...     

温度及pH敏感聚（丙烯酸）／聚（N—异丙基丙烯酰胺）互穿聚合物网络水凝胶的...

合成聚（丙烯酸）／聚（Ｎ－异丙基丙烯酰胺）互穿聚合物网络（ＰＡＡｃ／ＰＮＩＰＡ ＩＰＮ）水凝胶，具有温度及ｐＨ双重敏感特性。这种水凝胶在弱碱性条件下的溶胀率远大于酸性条件下的溶胀率。在酸性条件下，随着温度上升，凝胶的溶胀率也随之逐渐上升；而在弱碱性条件下，温度低于聚（Ｎ－异丙基丙烯酰胺）（ＰＮＩＰＡ）的较低临界溶解温度（ＬＣＳＴ）时，溶胀率也随着温度的上升而上升，而温度达到ＬＣＳＴ时，凝胶的溶胀率     

温度及pH敏感性N—乙烯基吡咯烷酮与丙烯酸β—羟基丙酯共聚物／聚（丙烯酸）互穿网络水凝胶的合成及其性能研究

由N－乙烯基吡咯烷酮与丙烯酸β－羟基丙酯共聚物／聚丙酸）所得的互穿网络水凝胶P（NVP－co-β－HPA）／PAA具有温度及pH双重敏感特性,在酸性条件下,由于P（NVP）与PAA间络合作用,随温度升高迅速退胀,在碱性条件下,凝胶的溶胀率远大于酸性条件下的溶胀率,且随温度的升高而逐渐增大。     

N-异丙基丙烯酰胺-丙烯酰胺热敏凝胶的溶胀特性

制备并表征了N-异丙基丙烯酰胺-丙烯酰胺热敏凝胶(NIPAm-Am),研究了单体配比、引发剂、交联剂用量和温度对其溶胀特性的影响。结果表明：NIPAm-Am热敏凝胶是由亲水和疏水基团组成的非晶高聚物。mAm／mNIPAm越大,凝胶的平衡溶胀率越大;增加交联剂的用量,凝胶的溶胀率减小,当引发剂的质量分数为0．008时溶胀率达最大值;温度的增加会使凝胶的溶胀率减小,在相转变温度时,溶胀率的变化最大。     

温度及pH敏感性N-乙烯基吡咯烷酮与丙烯酸β-羟基丙酯共聚物／聚(丙烯酸)互穿网络水凝胶的合成及其性能研究

由N-乙烯基吡咯烷酮与丙烯酸β-羟基丙酯共聚物／聚(丙烯酸)所得的互穿网络水凝胶P(NVP-co-β-HPA)／PAA具有温度及pH双重敏感特性.在酸性条件下,由于P(NVP)与PAA间络合作用,随温度升高迅速退胀;在碱性条件下,凝胶的溶胀率远大于酸性条件下的溶胀率,且随温度的升高而逐渐增大.     

新型阴离子型温敏水凝胶

新型阴离子型温敏水凝胶王昌华,曹维孝（北京大学化学与分子工程学院,北京,１００８７１）关键词温敏水凝胶,溶胀比,Ｎ－异丙基丙烯酰胺１９８４年Ｔａｎａｋａ等人［１］发现Ｎ－异丙基丙烯酰胺（ＮＩＰＡ）与Ｎ,Ｎ－亚甲基双丙烯酰胺（ＭＢＡ）的微交联共聚体,在...     

聚N-异丙基丙烯酰胺/纳米SiO2复合水凝胶的合成及溶胀性能

通过纳米SiO2的表面功能化,在其表面引入乙烯基功能基团,在H2O／THF的混合溶剂中,超声分散后,交联剂N,N′-亚甲基双丙烯酰胺存在时,于25℃下使其与N-异丙基丙烯酰胺共聚,制得聚N-异丙基丙烯酰胺,纳米SiO2复合水凝胶,并用FT-IR和SEM对产物进行了表征,研究了凝胶的溶胀动力学,消溶胀动力学和温度敏感性,实验结果表明,纳米SiO2的引入,改善了聚N-异丙基丙烯酰胺水凝胶在低温时的溶胀性能和在高温时对水的释放性能,并讨论了引起这些性能改变的原因。     

快速温度敏感聚(N-异丙基丙烯酰胺-co-丙烯酰胺)水凝胶的制备及性能研究

于 4 8℃下制备快速温度敏感聚 ( N -异丙基丙烯酰胺 -co-丙烯酰胺 )水凝胶 ,其在室温具有较大的平衡溶胀率 .通过改变丙烯酰胺的含量可以调节水凝胶的较低临界溶解温度     

P(NIPA-co-NVP)温敏性凝胶微粒的药物释放与降解

本文采用N-异丙基丙烯酰胺(NIPA)与N-乙烯基吡咯烷酮(NVP),以N,N-亚甲基双丙烯酰胺(MBA)为交联剂,氧化-还原试剂引发,通过反相悬浮共聚制备了微粒状热缩温敏水凝胶;研究了共聚单体配比及交联剂用量对凝胶温敏性能和溶胀性能的影响,并利用其温敏性以水杨酸为模型药物进行了药物吸附-释放实验;利用红外光谱和显微技术对微凝胶的结构和形态进行了表征,并初步探讨了该凝胶降解的可能性。实验发现:NVP单体的加入使共聚凝胶的体积相变温度和平衡溶胀率都明显升高,药物吸附率增加,而溶胀-退溶胀的响应速度及水保留率降低,释药率降低;该凝胶在pH1,37℃条件下能够降解,降解率随单体中NVP含量的增加而增加,随交联剂用量的增加而降低。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Theoretical and Experimental Chemistry - The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity...     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Synthesis of tetrabenzoporphins of the basis of isoindoline

Chemistry of Heterocyclic Compounds -