聚硅氧烷侧链液晶高分子的合成与表征

研究以对－烯丙氧基苯甲酸对－氰基苯酚酯为单体的聚硅氧烷侧链液晶高分子的合成方法。首先利用Williamson反应生成醚、羧酸酰化、酯化反应得到单体,然后利用硅氢化反应将单体接枝到聚甲基氢硅氧烷上得到目标产物。用IR,NMR及热台偏光显微镜等方法对单体和聚合物进行了结构表征和液晶行为分析。优化了对－烯丙氧基苯甲酸对－氰基苯酯为单体的聚硅氧烷侧链液晶高分子的合成工艺条件,提高了产率。样品表征结果证明单体和聚合物均呈现近晶液晶相,为特殊功能材料提供了原料。     

Studies on curing effect of phosphite monomer by EB radiation in the air

A new type phosphite active monomer was synthesized. The resisting oxygen inhibition effect of this monomer and the effects of irradiation dose and concentration of phosphite active monomer on curing were studied. At the same time, curing results were analysed, through gel content and IR spectrum. The excellent resisting oxygen inhibition result of this phosphite active monomer was shown by experiments. EB radiation curing in the air was successfully carried out by the phosphite active monomer.     

二甲基二烯丙基氯化铵反相乳液聚合动力学及机理的研究

研究以异构烷烃混合物为连续相,以丁二酸二(2-乙基)己酯磺酸钠(Sodium-di-2-ethylhexylsulfosuccinate,CH~3CH~2CH~2CH~2CH(C~2H~5)CH~2OCOCH(SO~3Na)CH~2COOCH~2CH(C~2H~5)-CH~2CH~2CH~2CH~3,AOT)和山梨糖醇单油酸酯(SMO)为乳化剂,以偶氮二异庚腈(ADVN)为引发剂的二甲基二烯丙基氯化铵的反相乳液聚合,得到了R~P~,~0=kc^0^.^4~Ⅰ~,~0c^0^.^5~A~O~Tc^-^0^.^4~S~M~Oc^3^.^0~M~,~0的表观动力学表达式。首次提出并研究了反相乳液聚合中单体在单体液滴和胶束中的分配系数对聚合动力学的影响,成功地解释了初始聚合反应速度和单体浓度三次方成正比的原因。通过对胶粒(latex)直径、单体在油相中的溶解度、聚合反应速度与AOT浓度及搅拌速度间的关系的测定,证明聚合反应是通过胶束(micelle)成核机理而进行的。通过对不同单体浓度下的^1H NMR盐效应的研究,证明溶液聚合的速度和单体浓度二次方成正比不是由于生成双分子π配合物,而是由静电屏蔽效应和粘度的改变引起的。     

甲基丙烯酸十二酯精制及其树脂性能研究

对工业级甲基丙烯酸十二酯单体进行了精制提纯,采用悬浮聚合法合成了甲基丙烯酸十二酯树脂。利用傅立叶变换红外光谱(FTIR)对精制前后单体以及树脂的结构进行了表征、利用热分析仪(TG)和差式扫描量热仪(DSC)对树脂的热性能进行了分析,同时研究了精制时碱液浓度对树脂饱和吸油率、吸油速率以及充分溶胀后树脂剩余率的影响。结果表明,精制后单体合成的树脂耐热性能有了明显改善,热降解温度大大提高;精制前后单体合成的树脂,由于杂质存在的缘故,其低温玻璃化转变类型明显不同;经6wt%碱液和8wt%碱液精制后单体的纯度有了明显提高,由其合成的树脂饱和吸油率,吸油速率都有较大提高,甚至接近化学纯单体合成树脂的饱和吸油率。     

Effects of monomer concentration on the structure and properties of polybenzidine micro rods

Polybenzidine was synthesized by interfacial polymerization under various monomer concentrations. Effects of monomer concentration on morphology, structure, and properties of polybenzidine were studied by techniques of Fourier Transform Infrared Spectroscopy, Ultraviolet Visible Absorption Spectroscopy, Scanning Electron Microscopy, Transmission Electron Microscopy, X-ray Diffraction, and Cyclic Voltammetry. The results showed that the synthesized polybenzidine with monomer concentration less than 0.15 mol/L were micro rod-like and the surface of the micro rods was smooth and uniform, However, the micro rod-like polybenzidine cannot be obtained under high monomer concentration because of the explosive polymerization. The results of structural analysis indicated that the monomer concentration should not be very high to obtain the polybenzidine with the optimal degree of conjugation and order arrangement of molecular chain. The polybenzidine synthesized in different monomer concentrations showed different electrochemical activities and the sample with the best electrochemical activity was obtained at monomer concentration of 0.02 mol/L.     

Study on functionalization of metal surfaces. III. Photopolymerization of monomer films on metal surfaces

The three kinds of monomer films on metal surfaces were deposited by adsorption from a solution of 6-polymerizable substituents-1,3,5-triazine-2,4-dithiol monosodium salts (RTDN); the polymerizable substituents such as cis-9-octadecenylamino, di(cis-9-octadecenyl)amino, and p-vinylbenzyl(cis-9-octadecenyl)amino groups were selected in view of the polymerization activity of unsaturated groups in the substituents and the packing degree of monomer molecules. The monomer films were estimated to consist of mainly 6-substituents-1,3,5,-triazine-2,4-dithione (3H, 5H) and to be multimolecular layers that are considerably cross-packed and ordered. The monomer films on metal surfaces were polymerizable under a UV light irradiation in air atmosphere to give polymer films. In the photopolymerization, azobis(isobutyronitrile) (AIBN) was very effective for increasing the monomer conversion and the polymerization rate. The optimum concentration of AIBN in monomer films was very small, about 0.025 mol %. The monomer conversion was influenced by the kind of monomers, namely, the polymerization activity and the packing degree. The effect of the packing degree was especially remarkable. The monomer conversion decreased with an increase in the thickness of monomer films. This is because the polymerization was initiated by oxygen and AIBN, which were diffused into the inner of monomer films. The possibility of polymerization of the unsaturated groups and the thione groups in monomer molecules under UV light irradiation is discussed.     

天然水中可溶性硅酸与铝盐作用机理探讨

通过考察单核铝和溶解铝浓度的变化, 对天然水体中溶解性硅酸与铝盐的反应机理进行研究. 试验过程中, 采用8-羟基喹啉荧光分光光度法测定铝浓度并结合热力学计算进行机理验证. 结果表明: 单体硅酸和聚硅酸主要与溶液中的单核铝反应生成溶解性硅铝酸盐. 单体硅酸与单核铝的结合能力较弱; 聚硅酸与单核铝的结合能力则较强, 反应产物主要为二啮或三啮配合物. 溶液pH对反应过程有着重要影响, 偏碱性环境对硅酸与单核铝间的反应具有促进作用.     

Improved imide receptors by imprinting using pyrimidine-based fluorescent reporter monomers

[reaction: see text] Optically responsive receptors toward imides based on 6-substituted 2,4-bis(acrylamido)pyrimidines are presented. The monomers were readily prepared in good yield. Solution binding to 1-benzyluracil (BU) monitored by 1H NMR appeared lower than a previously reported pyridine-based monomer. However, as indicated by 1H NMR and IR spectral investigations, the association strength was demonstrated to be "masked" by dimerization of the pyrimidine-based monomer units. Thus, from dilution experiments, a dimerization constant of 731 M(-1) was estimated for the pyrimidine-based monomer 2,4-bis(acrylamido)-6-piperidinopyrimidine whereas for the pyridine-based monomer 2,6-bis(acrylamido)pyridine, no self-association was observed. This precluded an accurate determination of the binding constant for BU to the former monomer whereas for the latter a binding constant of 757 M(-1) was measured. Despite the strong self-association, the novel monomer was shown to lead to enhanced imprinting effects when compared to imprinted polymers prepared analogously, but using the pyridine-based monomer as the recognition element. This was attributed to a higher intrinsic binding affinity exhibited by the pyrimidine based host monomer vis a vis the guest and the existence in the former of more than one interaction site for the guest. The monomers exhibited fluorescence emission informative of the mode of monomer incorporation in the polymer and the presence of guest species. Thus, the fluorescence was rapidly and selectively quenched upon template addition, with the degree of quenching correlating with binding affinity and the amount of template bound to the polymer.     

单体结构对紫外光固化氧阻聚影响的研究

利用光量热仪(UV-DSC)对单体TMPTA以及不同乙氧基化的TMPTA单体进行了紫外光固化实验。通过比较空气气氛和氮气气氛下光固化速率增长最快时的时间t_amax的差异来评价光固化初期氧阻聚的大小。考察了单体中乙氧基上的α-H的数量以及单体的流动特性对氧阻聚的影响。结果表明,提高单体中乙氧基的数量能减小光固化过程中的氧阻聚,氧阻聚的大小与单体中α-H的数量以及单体的黏度有关.     

Anionic heterogeneous polymerization of methacrylonitrile by n-butyllithium

The anionic heterogeneous polymerization of methacrylonitrile by butyllithium in petroleum ether was investigated. The polymerization was of the “living” type, as seen from the linear dependence of the molecular weights on [MAN]/[BuLi]. This behavior was further supported by block polymerization experiments in which the monomer was added in two portions and the molecular weights obtained were directly proportional to the total monomer concentration. The initiator efficiency was low, and initiator consumption was only about 2%. This fact, together with the results of the block polymerizations showed that there was preferential addition of monomer to the growing chain ends rather than to the initiator. The molecular weights were independent of the rate of monomer addition. This as well as the “living” behavior of the polymerization of methacrylonitrile on a wide range of monomer and catalyst concentrations and the absence of chain transfer to monomer was essentially different from that of the similar heterogeneous polymerization of acrylonitrile by butyllithium previously investigated. This is due to the absence of an α-acidic hydrogen in methacrylonitrile.     

SYNTHESIS AND FREE RADICAL POLYMERIZATION OF 2-OXO-3-METHYLEN E-5-PHENYL-1,4-DIOXAN

The novel cyclic monomer, 2-oxo-3-methylene-5-phenyl-1,4-dioxan, was synthesized by a set of reactions. Several intermediates were prepared and characterized in order to determine the monomer structure. The presence of chiral centers in the intermediates and resulting monomer makes it complicated to separate , purify and characterize them. It is a very reactive monomer which will polymerize even at room temperature if expose to moisture and air. This monomer can undergo essentially quantitative flee radical ring opening polymerization. The driving force for ring opening is the formation of new carbonyl group and benzylic radical. The monomer and polymer structure were established by IR, ~1H NMR, ~(13)C NMR and elemental analysis or high resolution mass spectrum. The molecular weight of the resulting polymer was estimated by viscosity determination.     

偶氮苯侧链共聚硅氧烷的合成及液晶行为的研究

以苯酚、十一烯酸、正溴己烷、对硝基苯酚和二氯亚砜为主要原料 ,通过取代、还原、重氮化和偶合等反应 ,合成了一种新的液晶单体 4 己氧基 4′ 十一烯 [1 0 ] 酰氧基偶氮苯 ,并与聚 (甲基氢硅氧烷 )通过硅氢加成生成一种新的高分子液晶 .通过1 H NMR和IR对单体和聚合物的结构进行了表征 ,并证实了聚合物的硅氢化程度近于完全 .通过DSC和热台偏光显微镜 (POM)对单体和聚合物的液晶行为进行了研究 ,证明了都具有液晶性     

近晶型聚硅氧烷侧链液晶的合成与表征

以烯丙基溴、对羟基苯甲酸、对氰基苯酚为主要原料合成了液晶基元对-烯丙氧基苯甲酸对-羟基苯氰酯,通过硅氢化加成反应将其接枝到聚甲基氢硅氧烷主链上,合成了一种新型的聚硅氧烷侧链液晶.通过傅里叶变换红外光谱仪(FT-IR)、氢核磁共振仪(1H-NMR)、差示扫描量热仪(DSC)、热台偏光显微镜(POM)和X-射线衍射仪(XR...     

含偶氮苯基侧基聚硅氧烷的合成及光致变色性

含偶氮苯基侧基聚硅氧烷的合成及光致变色性张其震，张静智，王艳（山东大学化学系济南２５０１００）（山东大学环境科学中心济南２５０１００）关键词聚硅氧烷，光致变色，光异构化，量子产率将光致变色性和液晶性化合物结合可得到新的多功能高分子材料，Ｒｉｎｇｅｄｏ...     

聚苯乙烯及其合金的热释放电流研究

聚苯乙烯及其合金的热释放电流研究盛京，李凤奎，胡静（天津大学材料科学与工程系，天津，３０００７２）关键词聚苯乙烯，聚苯乙烯松弛，热释电谱，聚苯乙烯合金，乙丙橡胶合金用热释放电流（ＴＳＣ）法研究聚苯乙烯（ＰＳ）的松弛过程只见Ｓｈｉｎｉｃｈｉ的报道［１］...     

对苯二胺和均苯三酸及对氨基苯甲酸制备可溶性芳香聚酰胺共聚物的研究

分别通过一步加料和分步加料的方法,以对苯二胺(A2)、均苯三酸(B3)和对氨基苯甲酸(AB)为原料进行溶液缩聚反应,制备了具有良好溶解性的芳香聚酰胺共聚物.产物的结构通过IR、1H-NMR得到证实.采用IR和1H-NMR对一步加料共聚反应的共聚行为进行研究,并初步考察了3种不同单体对反应的影响.     

Polymerization of isocyanates. V. Thermal degradation of polyisocyanates

Thermal degradation of polyisocyanates was investigated. The only degradation products were monomer and trimer. The main product was trimer for most aliphatic polymers, and monomer for aromatic polymers. Poly(cyclohexyl isocyanate) gave only its monomer on account of steric requirements. The apparent activation energy was calculated for aromatic polymers by using TGA and DTA curves.     

The preparation of sterically stabilized polymer dispersions

The emulsion polymerizations of styrene (St) and butyl acrylate (BA) stabilized by nonionic polyoxyethylene type emulsifiers did not show the long stationary rate interval. This was discussed in terms of two opposing effects: 1) the decreased monomer concentration at the reaction loci due to the depletion of monomer droplets or depressed monomer droplet degradation and 2) the increased number of polymer particles with increasing conversion. The continuous particle nucleation is attributed to the continuous release of emulsifier from the emulsifier saturated monomer droplets and/or the presence of monomer swollen micelles (microdroplets). The limited particle flocculation operative at lower emulsifier concentrations increases the nonstationary-state polymerization. The particle agglomeration is accompanied by the increased reaction order x (N_p vs. [E]^x) above 0.6. The increased uniformity of monomer emulsion stabilized by Tween 20 by homogenization of monomer emulsion increased the final conversion and the polymerization rate as well. The polymerization rate vs. conversion curve of the homogenized emulsion characterized with broader stationary rate interval reminds the four rate intervals system typical for miniemulsion. The accumulation of polymer and nonionic emulsifier within the monomer phase preserves the monomer droplets up to high conversion. The decreased monomer droplet degradation rises the monomer-starved condition or the depressed transport of both monomer and emulsifier to the reaction loci.     

含联苯结构侧链液晶聚合物的合成及相行为的研究

液晶聚合物从结构上可分为3种:侧链型、主链型和主侧链型。侧链型液晶聚合物主要是聚丙烯酸酯类、聚硅氧烷类以及磷腈聚合物类。Gray等对聚丙烯酸酯类含不同取代基的联苯结构液晶聚合物进行了研究,结果表明无间隔基且取代基为氰基和饱和脂肪基时,该聚合物呈现近晶型液晶行为。为了增加介晶单元的长径比及刚性,本文在聚甲基丙烯酸酯侧链     

Initiation Efficiency Reduction in Semicontinuous Styrene and Butyl Acrylate Emulsion Copolymerization Reactions

The decrease of initiation efficiency (radical entry efficiency) during seeded emulsion copolymerizations of styrene and butyl acrylate with different residual monomer reduction strategies was evaluated. Experiments were carried out using 50 and 99wt.% of styrene in monomer feed stream. Simulations were performed with a detailed mathematical model of the process that takes into account the diffusion control of initiation, propagation and termination. Results showed that the radical entry into polymer particles is strongly influenced by the aqueous phase kinetics and by the monomer solubility in aqueous phase. Simulation results were compared to experimental results of residual monomer and showed that the residual monomer content can be reduced by a temperature increase at the end of the polymerization. However, an additional feeding of more initiator, even when combined with such an increase of temperature, did not lead to a smaller residual monomer content due, mainly, the kinetic of termination in aqueous phase and radical anchoring. A model that accounts for the reduction of initiator efficiency (free radical entry efficiency) was successfully used to explain the behavior of the experimental observations and was able to correctly predict the qualitative trends of the effectiveness of different residual monomer reduction strategies.