窄分布聚甲基丙烯酸甲酯的合成与表征

甲基丙烯酸甲酯(MMA)的阴离子聚合,由于其聚合反应的特殊性和复杂性,早就引起人们的关注。长期以来,在各种引发剂、溶剂和温度等条件下都做了大量的研究。其中有关窄分布聚甲基丙烯酸甲酯(PMMA)合成方面的研究甚少。Anderson等用     

千克级窄分子质量分布聚苯乙烯的制备与表征

以正丁基锂为引发剂，以经过处理的工业级环己烷为溶剂、四氢呋喃为促进剂，用阴离子聚合的方法，在常压和惰性气体保护条件下，制得一系列千克级窄分子质量分布的聚苯乙烯，利用IR、^1H-NMR、GPC等技术对聚苯乙烯产物进行了表征，分析了影响聚苯乙烯的分子质量及分子质量分布的因素。     

苯乙烯-甲基丙烯酸甲酯嵌段共聚物的合成与表征

采用阴离子聚合技术合成了一系列苯乙烯-甲基丙烯酸甲酯的两嵌段共聚物(PS－b－PMMA)．采用GPC、FTIR、NMR(¹HNMR、¹³CNMR和固体NMR)和DMA等手段进行了表征．结果表明,所得产物为高分子量、窄分布、具有微相分离结构的两嵌段共聚物．     

反应性接枝共聚物──聚甲基丙烯酸甲酯－g－聚氧乙烯的合成与表征

The α-double bond and ω-carboxylic-tCndnated PEO macromer was synthesize suansfully and based on study of radical copolymendhon between PEO macromer and MMA., A series of reactive poly (methyl methacrylate)-g-tooly (ethylene oxide)-COOH) (PMMA-g-(PEO-COOH)) with different PEO contents was synthsind. The obtained produCts exhibited expected structure as indicated by IR, H-NMR, GPC and so on. The result of reaction betWeen PEO-COOH and amino add demonstrated that PEO-COOH exhibited the expeCted reactivity. The above results provide useful knowledge for the further study of the reaction between PMMA-g-(PEO-COOH) and bioactive materials.The solution behavior of thegraft copolymer was also reported.     

窄分子量分布聚四氢呋喃的合成

以发烟硫酸-高氯酸为催化剂,通过四氢呋喃的阳离子开环聚合合成了窄分子量分布的聚四氢呋喃(PTHF)。研究了发烟硫酸和高氯酸用量、反应时间、反应温度等对PTHF分子量(Mn)及其分布(Mw/Mn)的影响。结果表明,减少发烟硫酸或增加高氯酸用量可使Mn上升;反应时间超过3 h后,反应时间对Mn及Mw/Mn的影响不大;于2℃反应Mn有最大值(11 760);反应时间5 h,在N2中聚合的Mw/Mn较小;低转化率(Mw/Mn小于1.2)时,通N2对Mn(4 000~5 500)及Mw/Mn(1.12~1.19)的影响不大。     

聚苯乙烯-聚甲基丙烯酸缩水甘油酯嵌段共聚物的合成与表征

在常压、惰性气体保护下,以正丁基锂引发苯乙烯进行阴离子聚合,并用少量甲基丙烯酸缩水甘油酯(GMA)进行终端共聚,制得了侧基含有环氧基团的聚苯乙烯-聚甲基丙烯酸缩水甘油酯嵌段共聚物.用GPC、FT-IR、1H-NMR及盐酸-二氧六环银量法对共聚物进行了分析,并考察了GMA用量、终端共聚的反应温度及时间对环氧侧基数量的影响.结果表明:在少量四氢呋喃和氯化锂的存在下,1,1-二苯基乙烯(DPE)"盖帽"的聚苯乙烯阴离子活性种在甲苯溶剂中可引发GMA单体聚合反应,所得聚合物分子链中环氧侧基数量可根据需要进行调节.适宜的终端共聚反应温度和时间分别为-65℃和0.5 min.     

极性单体锂系阴离子嵌段共聚物的合成与表征

以酚锂作为副反应抑制剂, 以正丁基锂或1,1-二苯基乙烯盖帽的正丁基锂为引发剂, 通过顺次添加单体的方法, 合成了结构明确的聚异戊二烯-b-聚甲基丙烯酸甲酯(PI-b-PMMA)和聚甲基丙烯酸正丁酯-b-聚甲基丙烯酸甲酯(PBMA-b-PMMA)2种嵌段聚合物. 嵌段聚合反应中甲基丙烯酸甲酯(MMA)的转化率均高于90%, 通过核磁图谱计算的链节摩尔比与理论设计值吻合. PI-b-PMMA和PBMA-b-PMMA的分子量分别达到4×10⁴和1.6×10⁴. 在环己烷中, 通过顺次添加单体的方法, 合成了结构明确的聚苯乙烯-b-聚异戊二烯-b-聚甲基丙烯酸甲酯(PS-b-PI-b-PMMA)三嵌段共聚物, 各单体的转化率均达到100%, 并且产物中的链节摩尔比和理论设计值一致, 最终产物的分子量达到7.4×10⁴, 分子量分布仅为1.28, 为极性三嵌段热塑性弹性体以及有机玻璃透明增韧剂的工业化奠定了基础.     

聚苯乙烯/聚二甲基硅氧烷嵌段共聚物的合成与表征

通过阴离子溶液聚合合成了聚苯乙烯／聚二甲基硅氧烷的嵌段共聚物(PS-b-PDMS),并用GPC、FTIR、DMA,^1H-NMR、TEM等分析手段袁征了其结构与组成;电镜测得该嵌段共聚物的微区尺寸大约为20～30nm,与计算微区尺寸的结果相近。该共聚物具有非常低的表面能。     

在配位体络合体系中合成窄分布聚苯乙烯

本文报道了在RLi-配位体络合体系中阴离子聚合方法合成窄分布聚苯乙烯的研究结果.在己烷、庚烷、甲苯等溶液中合成分子量范围为10~2～10~3。的窄分布聚苯乙烯(MWD<1.10)时,以鹰爪豆矸、N,N,N’,N’-四甲基乙二胺为配位体的络合体系,聚合操作简便,效果非常好.在非极性溶剂中加一定比例的THF以后,该体系也能合成分子量范围为10~4～10~5的窄分布聚苯乙烯.     

甲基丙烯酸甲酯室温下的活性聚合——介绍一个高分子合成新实验

本文介绍了一个可用于实验教学的高分子合成新实验。利用基团转移聚合技术，在室温下进行极性单体甲基丙烯酸甲酯的活性聚合，可迅速得到平均分子量５０００～３００００、多分散性指数＜１．５的聚合产物。产物用ＧＰＣ进行表征，整个实验约６小时。     

希土离子单硫代二苯甲酰甲烷配合物的合成及性质研究

本文合成了单硫代二苯甲酰甲烷(HTDBM)和三价希土离子及路易斯碱(Q)的Ln(TDBM)_4QH型配合物(Ln=除Ce外的La～Lu,Q=二乙基胺)。测定了它们的摩尔电导值、红外光谱,可见—紫外光谱,核磁共振谱.观察到配合物是通过硫原子、氧原子同时与Ln~(3+)离子配位.Ln-O键强于Ln-S键。在Nd~(3+)、Pr~(3+)、Ho~(3+)、Er~(3+)离子的该类配合物的可见吸收光谱中发现超灵敏跃迁现象。讨论了题述配合物作为核磁共振化学位移试剂的可能性.     

希土离子单硫代二苯甲酰甲烷配合物的合成及性质研究

本文合成了单硫代二苯甲酰甲烷(HTDBM)和三价希土离子及路易斯碱(Q)的Ln(TDBM)₄QH型配合物(Ln=除Ce外的La～Lu,Q=二乙基胺).测定了它们的摩尔电导值、红外光谱,可见—紫外光谱,核磁共振谱.观察到配合物是通过硫原子、氧原子同时与Ln³⁺离子配位.Ln-O键强于Ln-S键.在Nd³⁺、Pr³⁺、Ho³⁺、Er³⁺离子的该类配合物的可见吸收光谱中发现超灵敏跃迁现象.讨论了题述配合物作为核磁共振化学位移试剂的可能性.     

STUDY ON THE SYNTHESIS AND PHYSICOCHEMICAL PROPERTIES OF SUCROSE POLYESTER

1. INTRODUCTIONSucrose polyester (SPE) is neither metabolized nor absorbed, it makes no caloric contribution to the diet. Excessive dietary fat intake is associated with increasing risk of obesity, high blood cholesterol, hypertension, coronary heart disease and some types of cancer. At present, fat substitutes are fashionable all over the world. SPE is a new functional fat substitute, which is similar to ordinary oils in physical and chemical properties. In a word, the research and dev…     

STUDY ON THE SYNTHESIS AND PHYSICOCHEMICAL PROPERTIES OF SUCROSE POLYESTER

Orthogonal test was used to evaluate the effects of synthetic such as temperature (120～140 ℃), reaction time (4-6) and substrate molar ratio of methyl oleate to sucrose (8:1-12:1) on the percent quantity conversion to sucrose polyester. Sucrose polyester was synthesized by a solvent-free one-stage interesterification. The optimum reaction conditions are as follows: methyl oleate/sucrose = 10∶1 (mol/mol); reaction temperature is 140 ℃;yield reaches 88.15%, and the degree of esterification (DE) is over 7 in the conditions. Thin layer chromatography (TLC), column chromatography (CC), High-performance liquid chromatography (HPLC) were used to analyze the product, the results show that the percent of sucrose polyoleate is over 70% in the product. The physicochemical properties of sucrose polyesters were compared with cooking oil. The results show that the qualities of sucrose polyesters are all up to the triglyceride.     

双变性淀粉吸附剂的合成及吸附性能研究

以环氧氯丙烷、交联化淀粉和丙烯腈为原料,水为溶剂,硝酸铈铵为引发剂,通过接枝反应合成了双变性淀粉吸附剂。其最佳制备工艺条件是交联化淀粉2g,硝酸铈铵浓度0.004mol/L,丙烯腈浓度0.3774mol/L,接枝温度35℃,接枝时间240min,料液比1:10(W/V)。对制得的双变性淀粉进行金属离子吸附性能评价,发现Cr6 吸附时使溶液处于中性或微酸性环境下,Cu2 吸附时使溶液处于弱碱性环境下,Cu2 的吸附率达到86.3%,Cr6 吸附率达78.2%,Cu2 吸附效果大于Cr6 。     

STUDY ON THE FORMATION MECHANISM OF MONODISPERSE PARTICLES IN THE EMULSIFIER-FREE EMULSION POLYMEAIZATION OF METHYL METHACRYLATE AND BUTYL ACRYLATE

The formation mechanism of monodisperse polymer latex particles in the emulsifier-free emulsion polymerizationof methyl methacrylate and butyl acrylate with potassium persulfate as initiator was investigated. A multi-step formationmechanism for the monodisperse polymer particles was proposed. The nucleation mechanism is considered to be thecoagulation of the precursor particles by homogeneous nucleation when the primary particles reach a critical size with highsurface charge density and sufficient stability. It had been proved by a special experiment that the early latex particles formedby the coagulation were stable. The primary particles grow by absorbing monomers and radicals in the polymerization systemand then become colloidally unstable again due to the understandable decrease of particle surface charge density, which leadsto the aggregation of the growing particles and the formation of larger latex pedicles therefrom. Aner the nucleation period,the preferential aggregation of the smaller particles in the propagation process leads to the change of the particles towards auniform size and narrower particle size distribution. The coexistence and competition of homogeneous nucleation,coagulation, propagation and aggregation result in the increase of the polydispersity index (U = D_(43)/D_(10)) in the first Stage,then its decrease in the later stage because of the competition of propagation and aggregation, and the gradual formation ofthe monodisperse particles.     

尾式苯丙氨酸卟啉铁（Ⅲ）配合物的合成及性质研究

尾式苯丙氨酸卟啉铁（Ⅲ）配合物的合成及性质研究＊倪春林（湖北三峡师范学院化学系宜昌４４３０００）王静秋秦子斌（武汉大学化学系武汉４３００７２）关键词苯丙氨酸卟啉铁配合物中图分类号Ｏ６２６．３２９取代四苯基卟啉铁（Ⅲ）由于合成方法简单，催化活性好等优点...     

聚甲基硅烷的合成与封端

利用Wurtz反应合成聚甲基硅烷 ,研究两类溶剂对其组成、分子结构和分子量的影响 .FT IR和1 H NMR及2 9Si NMR分析表明 ,以甲苯为溶剂 ,可以避免在溶剂化过程中Kumada重排的发生 ;而以THF 正己烷 (1∶6 ,V V)为溶剂 ,聚甲基硅烷容易支化和形成Si—CH2 —Si结构 .研究发现 ,聚甲基硅烷具有复杂的端基结构 ,封端剂的加入量影响着最终合成聚甲基硅烷的质量 .