An efficient synthetic-route to prepare [2,3,6-tri-O-(2-bromo-2-methylpropionyl]-β-cyclodextrin)

The efficient approach for the synthesis of [2,3,6-tri-O-(2-bromo-2-methylpropionyl]-β-cyclodextrin) (21Br-β-CD) is described. The reaction between 2-bromoisobutyric bromide and β-cyclodextrin was performed directly in 1-methyl-2-pyrrolidione solvent, leading to much less complicated procedures and higher yield (up to 89.5%) compared with those reported previously (17% yield). The product is an extremely useful initiator in synthesizing star polymers with well-defined structures using atom transfer radical polymerization for biomedical applications.     

Modification of Polymer Substrates with Low Surface Free Energy Material by Low‐Temperature Cured Polybenzoxazine

The B‐ala/AIBN PBZ system has a high extent of ring‐opening of oxazine because phenol‐containing oligomers are formed at the early stage of the curing process. As a result, the B‐ala/AIBN PBZ system possesses a relatively stronger intramolecular hydrogen bonding and lower surface energy than the pure B‐ala system at low temperature curing. In this context, poly(4‐vinyl pyridine), poly(4‐vinyl phenol) thin films and polycarbonate substrates, which lack liquid resistance, possess low surface free energy after modification with B‐ala/AIBN = 5/1 PBZ.

     

Intramolecular chain reaction of artemisinin oxidation

The intramolecular chain oxidation of artemisinin was analyzed using the parabolic model. The competition of the mono- and bimolecular peroxy radicals formed from artemisinin was considered. Artemisinin is predominantly oxidized via the intramolecular chain mechanism to form polyatomic hydroperoxides. This results in the situation when, under aerobic conditions, artemisinin is transformed from the monofunctional into polyfunctional initiator with several hydroperoxide groups. The enthalpy was calculated, and the activation energies and rate constants of the intramolecular reactions of the artemisinin peroxy radicals, as well as those of their bimolecular reactions with C-H, S-H, and O-H bonds of biological substrates and their analogs, were calculated in the framework of the parabolic model. A new kinetic scheme for artemisinin oxidation was proposed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 267–275, February, 2008.     

Atom Transfer Radical Polymerization of Methyl Methacrylate with α,α-Dichlorotoluene or α,α,α-Trichlorotoluene as Initiator

lnAtomTransferRadicalPolymerization(ATRP),whichisanew"living"/contr0lledradicalp0lymerizati0ntechniquedevel0pedindependentlybyMatyjaszewskieIallandSawam0t0eIaP,anyalkyIhalidewithactivatedsubstituents0na-carbonsuchasaryl,carb0nyl0rallylcanbeusedasinitiatoe.Benzy1haIideandpolymerswithbenzylhalideendgr0upwerereportedtobeefficientinitiator0rmacroinitiatorfortheATRPofstyrene".H0wever,whenbenzylhalidewasusedt0initiateMMAp0Iymerization,itwasfoundthattheinitiationefficiencywasveryIowinourlabo…     

一种新型香豆素酮可见光敏化染料的合成及其光引发性质的研究

高效的可见光光敏引发体系是目前光聚合研究中的重要领域.3,3′-二(7-二乙胺基)香豆素酮(R)已被公认为一种高效的可见光聚合敏化染料,并可以与Ar⁺激光488 nm波长匹配.本文新合成了一种染料3-(4-二乙胺基-苯丙烯酰基)-7-二乙胺基香豆素(S).实验发现在普通碘钨灯照射下,S/邻氯六芳基双咪唑(HABI)体系具有比已有高效染料R/HABI体系更快的光漂白速度和更高的引发聚合效率,是一种新型高效的可见光光敏聚合引发体系.而且S在不同溶剂中的最大吸收波长在452～489 nm之间,比R红移16～30 nm,因此该体系可以更好地与Ar⁺ (488 nm)激光器匹配.本文对该染料的光敏化机理进行了探讨.     

Bulk polymerization of N-vinylcarbazole initiated by C60

In this communication, we first used [60]fullerene as initiator to initiate the bulk polymerization of N-vinylcarbazole (NVC) monomer at 70°C (slightly higher than the melting point temperature, 65°C, of NVC). A reasonable polymerization reaction pathway via C₆₀-NVC ion-radical pairs is suggested. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3745–3747, 1999     

双官能度引发剂引发苯乙烯聚合微观动力学

采用 2 ,5 二甲基 2 ,5 二己酰基过氧化己烷 (DMDEHPH)为引发剂 ,在 5 5～ 80℃下引发苯乙烯聚合 .通过研究影响聚合速率的各种因素 ,得出了聚合速率对单体浓度和引发剂浓度的级数分别为 1 0和 0 5次、聚合活化能为 92 0kJ mol、引发效率为 0 5 5± 0 0 3.温度一定 ,引发效率随引发剂浓度的增加而减小 .求得 6 0和70℃下DMDEHPH向引发剂的链转移常数分别为 0 0 37和 0 0 4 8、向单体的链转移常数分别为 0 5 9× 10 - 4和0 75× 10 - 4.     

三臂ATRP引发剂的合成及应用

分别以三乙醇胺、三聚氰胺为原料,通过酰化反应合成了三种具有配体功能的三臂原子转移自由基聚合(ATRP)引发剂:三[2-(2-溴异丁酰氧基)乙基]胺,三[2-(4-氯甲基苯甲酰氧基)乙基]胺和2,4,6-三(2-溴异丁酰胺基)-1,3,5-三嗪,收率分别为81%,69%和83%。以三[2-(2-溴异丁酰氧基)乙基]胺既作引发剂又作配体进行甲基丙烯酸甲酯(MMA)的ATRP乳液聚合,结果表明反应前期与中期具有活性/可控特征。     

无机物表面引发聚合反应制备端接枝聚合物膜*

无机物表面引发聚合反应是聚合物合成化学的又一新领域。分子自组装技术的发展使得各种类型的聚合反应都有转移到固体表面进行的可能。本文综述了无机物表面引发聚合反应用于制备高键合密度端接枝聚合物膜的研究进展,并对其今后的发展提出了见解。