固定化酶新载体-N′-ε-甲基丙烯酰胺基己酸酯的研究

合成了一种新的反应性聚合物聚N-ε-甲基丙烯酰胺基己酰氧-5-降冰片烯-2,3-双甲酰亚胺[P(MACONB)],其相应的新单体N-ε-甲基丙烯酰胺基己酰氧-5-降冰片烯-2,3-双甲酰亚胺(MACONB),是由N-ε-甲基丙烯酰胺基己酸(MACOH)与N-羟基-5-降冰片烯-2,3-双甲酰亚胺(HONB)在环己基羰二亚胺存在下经偶联成酯反应而得。反应性聚合物P(MACONB)是一个较好的固定化胰蛋白酶的载体,它极易与胰蛋白酶在温和反应条件下进行胺解反应,形成一个具有较高酶活力的固定化胰蛋白酶。     

N-甲基丙烯酰-N′-嘧啶基哌嗪及其聚合物敏化的丙烯腈光聚合

我们曾报道过同一分子中含有给电子生色基团和电子受体基团的一类功能性单体,如甲基丙烯酸-4-N,N-二甲氨基苄酯(DMABMA),N-(4-N′,N′-二甲氨基苯基代丙烯酰胺,N-(4-N′、N′)-二甲氨基苯基代甲基丙烯酰胺(DMAPMA),8-丙烯酰氧喹啉(AQ),N-丙烯酰-N′-苯基哌嗪(APP)的合成、聚合以及单独或与过氧化二酰构成氧化还原体系以引发烯类单体的聚合研究。N-甲基丙烯酰-N′-嘧啶基哌嗪(MPMP)     

酰亚胺及磺酰苯酰亚胺的氰甲基化新方法

二乙胺基乙腈分別与苯邻二酰亚胺、丁二酰亚胺或邻-磺酰苯酰亚胺反应后,可生成相应的N-氰甲基苯邻二酰亚胺、N-氰甲基丁二酰亚胺,N-氰甲基邻磺酰苯酰亚胺及O-氰甲基邻磺酰苯酰亚胺。酰亚胺或磺酰苯酰亚胺的氰甲基化反应活性,随氮负离子的稳定性及其酸性增强而增大。     

N-(2-乙烯氧乙基)-1,8-萘二甲酰亚胺聚合物与共聚物的荧光行为

<正> 我们曾报道过一系列含有给电子生色基团的丙烯酰类单体如甲基丙烯酸二甲氨基苄酯、N-(N′,N′-二甲氨基苯基)丙烯酰胺类、8-丙烯酰氧喹啉类、N-丙烯酰-N′-苯基哌嗪类、N-丙烯酰-N′-嘧啶哌嗪类、N-甲基丙烯酰氧乙基-N-甲基代苯胺等的合成、聚合、引发行为以及它们的聚合物的荧光行为。这些单体结构的共同点在于其双键为缺电子性而生色基团为给电子性,因而在荧光行为上,由于生成激基复合物或电荷转移而发生荧光     

2-丙烯酰氧基丙烯酸酯的合成及其环化聚合

本文报告2-丙烯酰氧基丙烯酸甲酯和乙醇(V_a,V_b)和2-甲基丙烯酰氧基丙烯酸乙酯(V_c)等三种1,5-二烯类单体的合成和聚合工作。 2-羟基-3-氯丙酸酯分别与3-氯丙酰氯及2-甲基-3-氯丙酰氯反应,生成相应的2-(3’-氯丙酰氧基)-3-氯丙酸甲酯和乙酯(IV_a,IV_b)和2-(2’-甲基-3’-氯丙酰氧基)-3-氯丙酸乙酯(IV_c)。IV在三乙胺的作用下,消去两分子的氯化氢而得到相应的单体(V)。V易进行聚合反应。从其溶液聚合物的溶解性能、双键分析值和红外吸收光谱,证明聚合反应主要是按环化聚合反应机理进行的,生成具有γ-内酯环型结构重复单位的聚合物。     

苯乙烯与N-取代马来酰亚胺的可逆加成-断裂链转移交替共聚合

研究了二硫代苯甲酸酯存在下偶氮二异丁腈引发苯乙烯(St)、St与N-对羟基苯基马来酰亚胺(HPM)、St与N-对(2-氯/溴丙酰氧基)苯基马来酰亚胺(CPPM/BPPM)的可逆加成-断裂链转移(RAFT)均/共聚,聚合物的结构由紫外-可见光(UV-Vis)与凝胶渗透色谱(GPC)表征.结果表明,St的RAFT均聚以及St与N-取代马来酰亚胺的RAFT共聚均呈现活性聚合特征,分子量随着转化率上升而增加,且分子量分布较窄.对于St的RAFT均聚,由于双基终止,聚苯乙烯(PSt)链中"戴帽效率"随着转化率上升逐渐下降.对于St与N-取代马来酰亚胺的RAFT共聚合,电荷转移复合物的形成显著地提高了共聚反应速度,并促进交替结构的形成.随后进行了以P(St-alt-BPPM)引发St的原子转移自由基聚合以制备梳型PSt,结果表明在强极性溶剂中进行的聚合过程失去可控性,所得产物分子量极宽,而在本体聚合中所得聚合物分子量相对较窄,有一定的可控性.     

N-溴代丁二酰亚胺促进的环丙烯羧酸酯的区域选择性开环反应

环丙烯类化合物含有环内碳碳双键,巨大的环张力导致其具有活泼的化学反应特性.主要研究了N-溴代丁二酰亚胺促进的环丙烯二羧酸酯类化合物的区域选择性开环,得到官能化的α,β-不饱和羧酸酯类化合物.该反应条件温和,操作简单.     

具有阳离子表面活性ATRP引发剂的合成

以2-溴异丁酰溴、2-溴乙醇、6-氯-1-己醇及N,N-二甲基正十二烷基胺为主要原料,分别通过两步或三步反应合成了具有阳离子表面活性的原子转移自由基聚合(ATRP)引发剂——N-[2-(2-溴-2-甲基丙酰氧基)乙基]-N,N-二甲基正十二烷基溴化铵或N-[6-(2-溴-2-甲基丙酰氧基)己基]-N,N-二甲基正十二烷基碘化铵,其结构经1H NMR,13C NMR,IR和元素分析表征。     

a-（取代苯氧基苯甲酰氧基）烃基膦酸酯的合成方法

采用两种合成路线来合成O，O-二乙基-a-(2-氯-4-三氟甲基苯氧基苯甲酰氧基)丙基膦酸酯，并对其结果进行了比较分析，以此来探讨a-(取代苯氧基苯甲酰氧基)烃基膦酸酯的合成方法。     

α-(取代苯氧基苯甲酰氧基)烃基膦酸酯的合成方法

采用两种合成路线来合成 O,O-二乙基 -α- (2 -氯 - 4-三氟甲基苯氧基苯甲酰氧基 )丙基膦酸酯 ,并对其结果进行了比较分析 ,以此来探讨 α- (取代苯氧基苯甲酰氧基 )烃基膦酸酯的合成方法     

Kinetics of solid phase thermal polycondensation of aspartic acid in evacuated system

Solid phase thermal polycondensation of aspartic acid in evacuated system results in formation of poly(aspartic acid) at 190–207°C and in poly(succinimide) at 210–230°C. Kinetic parameters of formation of poly(aspartic acid) and poly(succinimide) have been determined. The aspartic acid → poly(aspartic acid) → poly(succinimide) polycondensation is accompanied by partial decarboxylation of the monomeric units.     

Synthesis and radical polymerization of end-methacrylated poly(succinimide) leading to poly(aspartic acid) hydrogel

The polycondensation of aspartic acid in the presence of phthalic anhydride was carried out in mesitylene/sulfolane using o-phosphoric acid as a catalyst. The polymer yields were 91–78%, when 5–20 mol-% phthalic anhydride was added into the feed. The obtained poly(succinimide) carried a phthalic imide unit and a succinic acid unit as end groups. In the MALDI-TOF mass spectrum, the peak-to-peak distances between adjacent signals were 97.07 m/z, corresponding to the calculated value (97.07) of the succinimide unit. Poly(succinimide) was reacted with 2-(methacryloxy)ethyl isocyanate to give end-methacrylated poly-(succinimide), in which the end-functionality of the methacrylate group was ca. 1. End-methacrylated poly-(succinimide) was polymerized with ethylene glycol dimethacrylate using 2,2′-azoisobutyronitrile to give poly(succinimide) gel, which could be converted into water-absorbing poly(aspartic acid) hydrogel.     

New catalytic systems for the manufacture of poly(aspartic acid)

Aspartic acid (I), when heated to a temperature in excess of 180 °C, undergoes a solid-state condensation polymerization to afford the useful polymeric intermediate known as poly(succinimide) (II). Treatment of poly(succinimide) with aqueous base, such as sodium hydroxide, affords sodium poly(α,β-DL-aspartate) (III) also known as thermal poly(aspartate) (TPA). Acid catalysts, such as phosphoric acid have been added to the aspartic acid to afford higher-molecular-weight poly(succinimide) than is obtained in the non-catalyzed polymerization. Recently, new sulfur-based catalysts have been disclosed for the polymerization of aspartic acid. The sulfur-containing catalysts provide a route to highly biodegradable, low-color poly(aspartate)s in the molecular weight range of 2 000 to 20 000. A comparison of biodegradability, molecular weight, and spectral characteristics of the poly(succinimide)s and poly(aspartate)s derived from the catalyzed and non-catalyzed polymerizations is presented.     

聚天冬氨酸硅质固定相的研制及应用

D，L-天冬氨酸在浓磷酸的存在下加热聚合生成聚琥珀酰亚胺，此产物能与氨丙基硅胶快速反应生成聚琥珀酰胺硅胶，然后再水解生成聚天冬氨酸硅质固定相．并对反应条件进行了优化、实验表明，聚天冬氨酸固定相对蛋白质有较好的分离能力和选择性．     

Thermogelation of amphiphilic poly(asparagine) derivatives

Thermoresponsive sol–gel transition polymers based on biodegradable poly(amino acid) were synthesized by the reaction of poly(succinimide) with dodecylamine and amino alcohols. The introduction of the hydrophobic amine into the thermoresponsive poly(amino acid)s induced the sol–gel transition in phosphate buffer saline. The effects of the side chain structure, molecular weight, concentration of the polymer, and the additives (inorganic salts and urea) in the solution on the thermoresponsive behaviors were systematically investigated. A relationship between the lowest critical solution temperature (LCST) in the dilute solution and the viscosity reduction of the concentrated solution upon heating was observed. The present poly(amino acid)s showing a thermoresponsive sol–gel transition in aqueous solutions possess immense potential as an injectable biodegradable hydrogel system for various biomedical applications. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis of polyaspartate macromonomer having a vinyl end group and application to dispersion copolymerization of styrene

Sodium polyaspartate (PAspNa) macromonomer with an acryloyl end group was synthesized for dispersion polymerization. At first, a poly(succinimide) (PSI) derivative with a hydroxyphthalimide end group was synthesized by polycondensation of l-aspartic acid and 4-hydroxyphthalic acid. Then, the PSI derivative was end-capped with an acryloyl group by a reaction with acrlyloyl chloride. Finally, a PAspNa derivative with a vinyl end group was synthesized by a hydrolysis of succinimide units by sodium hydroxide. The synthesized macromonomer was applied as a polymerizable stabilizer in dispersion copolymerization of styrene in a mixture of ethanol and water. The PAspNa macromonomer acted as an effective stabilizer and gave sub-micron-sized polymeric particles in dispersion polymerization in polar medium.     

N,N′-亚甲基双丙烯酰胺与4-乙烯基吡啶共聚微凝胶的γ-射线辐照合成

通过γ 射线辐照技术 ,在稀水溶液中实现了N ,N′ 亚甲基双丙烯酰胺 (Bis)与 4 乙烯基吡啶 (4 VP)的无皂乳液共聚 ,得到平均流体力学半径 (Rh)为 5 6～ 15 2nm的一系列微凝胶 ,并通过红外光谱、热分析、透射电镜进行了表征 .通过测定Rh、吸光度、凝胶比 ,研究了与Bis共聚的单体及比例、剂量和剂量率对微凝胶合成的影响 .结果表明 ,微凝胶的大小可以通过吸收剂量、单体相对含量的改变来进行控制 .最后 ,对微凝胶的形成机理进行了初步探讨 .     

Molar Mass and Structural Characteristics of Poly[(lactide-co-(aspartic acid)] Block Copolymers

Summary: We report on various synthetic procedures for the preparation of biodegradable and biocompatible poly(lactide-co-aspartic acid) block copolymers based on natural monomeric units – lactic acid and aspartic acid. Multiblock poly(lactide-co-aspartic acid) copolymers of different comonomer composition were synthesized by heating a mixture of L-aspartic acid and L,L-lactide in melt without the addition of any catalyst or solvent and with further alkaline hydrolysis of the cyclic succinimide rings to aspartic acid units. Diblock poly(lactide-co-aspartic acid) copolymers with different block lengths were prepared by copolymerization of amino terminated poly(β-benzyl-L-aspartate) homopolymer and L,L-lactide with subsequent deprotection of the benzyl protected carboxyl group by hydrogenolysis. The differences in the structure, composition, molar mass characteristics, and water-solubility of the synthesized multiblock and diblock poly(lactide-co-aspartic acid) copolymers are discussed.     

SURFACE MODIFICATION WITH HYDROGELS VIA MACROINITIATORS FOR ENHANCED FRICTION PROPERTIES OF BIOMATERIALS

ABSTRACT

A general method of surface modification is described which is based on dip-coating of a substrate with a macroinitiator and subsequent free radical polymerization of functional monomers. Using this method, it is possible to fix poly(acrylic acid) hydrogels on polymer surfaces, e.g. on catheters, which drastically reduces the friction of these materials. Similarly, other biological relevant properties, especially reduced protein or bacteria adsorption can be achieved by choosing appropriate monomers.

The substrate was first homogeneously dip-coated with e.g. the water-insoluble macroinitiator poly(octadecene-co-maleic anhydride), partially reacted to the tert.-butyl perester. Homogeneity, thickness, and reactivity of the macroinitiator layer was characterized in detail. After a temper step, surface homo- and copolymerizations of ionic monomers were carried out in water directly from the modified surface. The consistency of the hydrogel coating could be well controlled by the reaction conditions and the monomer composition. The correlation between the experimental parameters, the composition of the surface coating, and the friction properties was established. A relatively thick, slightly crosslinked poly(acrylic acid) hydrogel coating reduces the friction coefficient by 95% compared to that of uncoated surfaces.     

Water-Soluble imide-amide copolymers. I. Preparation and characterization of poly [acrylamide-co-sodium N-(4-sulfophenyl) maleimide]

Sodium N-(4-sulfophenyl) maleimide (SPMI) and its saturated succinimide counterpart were first prepared according to established methods. Hydrolysis experiments on these monomers monitored by ¹H-NMR showed that although SPMI monomer was about 15% hydrolyzed in D₂O at 23°C in 24 h. Sodium N-(4-sulfophenyl) succinimide, which is similar in structure to the imide units in the copolymers, was only 1% hydrolyzed after 18 days at 23°C and 29% hydrolyzed after 18 days at 60°C. This indicated that the saturated imide rings in the copolymer might be sufficiently stable to hydrolysis for the copolymers to be useful. However, hydrolysis at high pH demonstrated that the imide rings would be rapidly saponified under alkaline conditions, destroying the structural rigidity that the intact rings might have provided in the copolymer chains. Sodium N-(4-sulfophenyl) maleimide (SPMI) was copolymerized with acrylamide in water at 30°C without cleavage of the imide ring. Water-soluble poly [acrylamide-co-sodium-N-(4-sulfophenyl) maleimide] (PAMSM) samples containing from 7.4 to 64 mol % imide were prepared. Photoacoustic FTIR and ¹³C-NMR spectra were used to confirm the structure of the copolymers obtained. Elemental analysis was used to determine the imide content of the copolymers, and from this composition data reactivity ratios were calculated for the two component monomers.