紫外光引发聚乙二醇二甲基丙烯酸酯的RAFT交联聚合研究

合成了S-1-十二烷基-S′-(α,α′-二甲基-α″-乙酸)三硫代碳酸酯(TTC),以此为链转移剂,采用光差动热分析仪(DPC)和动态力学分析(DMA)方法研究了室温条件下紫外光引发的聚乙二醇二甲基丙烯酸酯(PEGDMA)的可逆加成-断裂链转移(RAFT)自由基聚合行为.发现RAFT光聚合反应的反应速率小于常规自由基聚合,因为体系由扩散控制,反应中自加速趋势减缓.探讨了双键之间聚乙二醇链段长度对于聚合速率和最终转化率的影响.结果发现,随着中间聚乙二醇链段的增加,聚合速率先变小再变大,最终转化率缓慢变大.RAFT光交联产物的交联密度随中间链段长度的增加而下降,交联均匀性提高.     

含三氟甲基1,2,3-三氮唑衍生物对蘑菇酪氨酸酶活性的抑制动力学(英文)

研究表明,含三氟甲基1,2,3-三氮唑衍生物(TF-TZ)对蘑菇酪氨酸酶具有很强的抑制性:不仅抑制单酚酶活性,而且对二酚酶活性也是可逆性抑制,其半抑制浓度IC50分别为30.4和34.5μmol.L-1,并且单酚酶延滞时间随着TF-TZ浓度增加而延长.TF-TZ对二酚酶的抑制为抛物线型竞争性抑制,表明一分子的酶可以和两分子的TF-TZ相结合,从而形成两种酶-抑制剂复合物:EI和EI2,其抑制常数分别为76.9和9.71μmol.L-1.紫外-可见光谱表明,TF-TZ和酶相互作用后产成特征的"肩峰",说明TF-TZ能够作用于酶的活性中心.     

含氟丙烯酸酯与苯乙烯共聚物的RAFT合成及表征

通过可逆加成-断链链转移(RAFT)溶液聚合,以三硫代碳酸酯为RAFT试剂,偶氮二异丁腈(AIBN)为引发剂,1,4-二氧六环为溶剂,制备甲基丙烯酸(2,2,2-三氟)乙酯(TFEMA)和苯乙烯(St)共聚物.详细研究了不同引发剂的用量、RAFT试剂与引发剂摩尔比以及聚合温度等实验条件对聚合反应过程的影响.通过GPC、FTIR测试共聚物的分子量、分子量分布和分子结构,并用静态接触角仪和AFM分别表征聚合物膜的接触角、表面能及膜的表面形貌.     

判断聚对苯基热解碳嵌锂容量的简单方法

The method to evaluate the reversible lithium insertion capacity (Qre) has been studied using poly (p-phenylence) (PPP) heat-treated at 550 1000 ℃ in inert gas atomsphere by H/C atomic ratio and FTIR measures. The H/C atomic ratio and Qre decreased with increasing heat-treament temperature. The absorption ratio of 1020cm-1 band to the 1440cm-1 band (Ra) is directly related to the Qre of carbon samples. The samples with R. >1-1 and without 807cm-1 peak tend to have high Qre (>372 mA.h-g-1). The reversible capacity for Li+ ion insertion decrease as Ra decreases.     

Electrochemical nucleation of lead and copper on indium-tin oxide electrodes

The nucleation process of Pb and Cu onto indium-tin oxide electrodes was studied by single potentiostatic steps using 0.1×10^–4 mol L^–1 Cu(NO₃)₂ and 2×10^–2 mol L^–1 Pb(NO₃)₂ solutions in aqueous 1.0 mol L^–1 NaNO₃. The current, I_max, and the time, t_max, corresponding to the maximum, were evaluated by 3D nucleation with a diffusion-controlled growth model for instantaneous and progressive nucleation. The non-dimensional plots of (I/I_max)² vs. t/t_max showed that Cu and Pb nucleation closely followed the response predicted for instantaneous nucleation. Other parameters, such as I vs. t^1/2 and I²_maxt_max, as well as nuclei micrographs, were analyzed, corroborating the results obtained.     

基于树形链转移剂的可逆加成断裂链转移聚合

可逆加成断裂链转移(RAFT)聚合是最近十多年来发展起来的一种活性/可控技术,链转移剂(CTA)为该技术的核心.本文介绍了采用R路径合成法、Z路径合成法合成R核与Z核树形链转移剂以及它们调控不同单体的RAFT聚合,合成树形-线性二嵌段共聚物、树形-线性-树形三嵌段共聚物和树形-星形聚合物等树枝状聚合物的研究进展.     

液滴在超疏水形状记忆微阵列表面上定向/非定向滚动的可逆调控

利用3D打印、 模板赋形和表面修饰的方法, 制备出具有竖直结构的超疏水形状记忆微阵列. 该微阵列的竖直状态和倾斜状态能够基于形状记忆效应进行可逆调控. 当微阵列的结构发生改变, 液滴在表面的滚动状态也随之发生变化. 液滴在竖直的微阵列上表现出非定向滚动特征, 即液滴向微阵列两侧运动的滚动角是一致的. 在倾斜的微阵列上, 液滴则表现出定向运动的功能, 即液滴沿着微阵列倾斜方向上的滚动角要小于逆着阵列倾斜方向的滚动角. 因此, 本文通过调控微阵列形态实现了对液滴定向/非定向滚动的可逆调控.     

热动力学对比进度法 I. 可逆反应热动力学模型

引入“对比进度”的概念, 建立了可逆反应动力学新的数学模型, 提出了可逆反应动力学的对比进度研究法. 并用热导式自动热量计研究了一个可逆反应体系, 计算结果与文献值符合甚好, 验证了数学模型及对比进度法的正确性.     

偶氮苯功能化的光响应共价有机框架材料

通过后修饰的方法,在共价有机框架(COFs)材料JUC-500的孔道中引入光敏性的偶氮苯小分子,合成了具有光热刺激响应的共价有机框架材料JUC-501.在紫外线和加热作用下,孔道中的偶氮苯会发生可逆的顺-反异构变化,对染料污染物甲基橙(MO)表现出优异的可逆吸附与释放性能.     

Synthesis of poly(vinyl acetate) with fluorescence via a combination of RAFT/MADIX and “click” chemistry

A novel ω-azido-functionalized RAFT reagent, O-(2-azido-ethyl) S-benzyl dithiocarbonate (AEBDC), was synthesized and subsequently employed to mediate the reversible addition-fragmentation chain transfer (RAFT) polymerization of vinyl acetate (VAc) to prepare end-functionalized polymers. The polymerization results showed that the RAFT polymerizations of VAc could be well controlled using AEBDC as the RAFT agent. Number-average molecular weights (M_n GPC) increased linearly with monomer conversion, and molecular weight distributions were relatively narrow. ¹H NMR spectrum of the poly(vinyl acetate) (PVAc) confirmed the existence of functional azido group at the end of the polymers chains. The ω-azido-terminated polymers were coupled by “click” chemistry with a fluorescent alkyne, 7-propinyloxy coumarin, to prepare fluorescent PVAc. The fluorescence properties of the PVAc homopolymers before and after coupling with 7-propinyloxy coumarin in CH₂Cl₂ solution were investigated.