基于DMAEMA的可聚合离子液体及其与HEMA交联共聚物凝胶的研究

以丙酮为溶剂,分别采用丙酸(AS)、磷酸(H3PO4)以及2-丙烯酰胺基-2-甲基丙磺酸(AMPS)中和甲基丙烯酸-N,N-二甲基胺基乙酯(DMAEMA),然后减压蒸馏去除溶剂,合成了3种可聚合离子液体DMAEMA-AS/H3PO4/AMPS,采用差示扫描量热(DSC)表征其玻璃化温度(Tg)。以过硫酸铵(APS)为引发剂,以N,N-亚甲基双丙烯酰胺(MBAM)为交联剂,甲基丙烯酸-2-羟基乙酯(HEMA)分别与3种可聚合离子液体在水溶液中交联共聚,合成了Poly(HEMA-co-DMAEMA-AS/H3PO4/AMPS)凝胶,采用重量法研究了3种凝胶的溶胀行为。结果表明,DMAEMA-AS/H3PO4/AMPS的玻璃化温度分别为-61.9℃、76.2℃、-45.8℃,Poly(HEMA-co-DMAEMA-AS)和Poly(HEMA-co-DMAEMA-H3PO4)凝胶可在水及多种有机溶剂中溶胀,而Poly(HEMA-co-DMAEMA-AMPS)凝胶在任何溶剂中均不溶胀,并初步探讨了产生这种现象的原因。     

Atom transfer radical polymerization (ATRP): A versatile and forceful tool for functional membranes

The progress in atom transfer radical polymerization (ATRP) provides an effective means for the design and preparation of functional membranes. Polymeric membranes with different macromolecular architectures applied in fuel cells, including block and graft copolymers are conveniently prepared via ATRP. Moreover, ATRP has also been widely used to introduce functionality onto the membrane surface to enhance its use in specific applications, such as antifouling, stimuli-responsive, adsorption function and pervaporation. In this review, the recent design and synthesis of advanced functional membranes via the ATRP technique are discussed in detail and their especial advantages are highlighted by selected examples extract the principles for preparation or modification of membranes using the ATRP methodology.     

高吸水性树脂AA/DMAEMA的常温合成研究

以丙烯酸(AA)和甲基丙烯酸-N,N’-二甲氨基乙酯(DMAEMA)为原料,N,N’--亚甲基双丙烯酰胺为交联剂,采用常温水溶液聚合法合成了耐盐性能良好的高吸水性树脂。研究了合成的有关工艺条件对产物吸水性能的影响。在AA/HEMA为95/5(摩尔比),交联剂质量分数0．0002％,引发剂质量分数为0．46％,还原剂用量为0．23％时,合成树脂的吸水率700 g/g,吸收1％的氯化钠溶液能力大于80g/g。     

DMAEMA/NVP/HEMA共聚物水凝胶的合成与性能研究

以甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)、N-乙烯基吡咯烷酮(NVP)和甲基丙烯酸β-羟乙酯(HEMA)为共聚单体,采用自由基水溶液聚合法制备了化学交联的三元共聚水凝胶,并对水凝胶在不同温度和不同离子强度及不同pH介质中的溶胀性能进行了测定。结果表明,在不同离子强度(I)的水溶液中,随着I的增大,水凝胶的平衡溶胀比ESR不断降低;但当I>0.2后,对凝胶ESR的影响不显著;当外界环境酸度较大(pH<2)时,凝胶ESR较大,但pH值稍有增大,凝胶ESR迅速下降;温度升高,凝胶ESR减少。     

甲基丙烯酸-N,N-2-甲基乙胺酯原子转移自由基聚合反应表观反应级数研究

为了研究甲基丙烯酸-N，N-2-甲基乙胺酯(DMAEMA)原子转移自由基聚合的表观反应级数，应用初级自由基的原子转移化学反应平衡、链自由基的链增长反应以及链自由基的原子转移化学反应平衡等三类基元反应构成的DMAEMA原子转移自由基聚合反应机理，通过建立聚合反应的动力学模型，研究了在DMAEMA原子转移自由基聚合反应的链引发体系中，链引发剂和催化剂的表观反应级数。结果表明，在DMAEMA原子转移自由基聚合反应的链引发体系中，链引发剂EBIB和催化剂溴化亚铜的表观反应级数均为0．8985。研究了在DMAEMA原子转移自由基聚合反应体系中，链引发剂和总的链增长自由基的浓度随单体转化率的变化关系。在聚合反应初期，总的链增长自由基的浓度随单体转化率的增加而急剧增加，当单体转化率达到40％时，总的链增长自由基的浓度近似保持为常数。链引发剂的浓度在反应初期迅速减少，表明在DMAEMA原子转移自由基聚合反应的早期，体系中存在大量的初级自由基，这些初级自由基使得大部分的链自由基在很短的时间内生成。     

Ultra high molar mass poly[2-(dimethylamino)ethyl methacrylate] via atom transfer radical polymerization

Well-defined high molecular weight poly[2-(dimethylamino)ethyl methacrylates] [poly(DMAEMA)s] with molar masses up to ∼1×10⁶ g/mol were successfully synthesized via atom transfer radical polymerization (ATRP). This was achieved by using p-toluenesulfonyl chloride(p-TsCl)/CuCl/1,1,4,7,10,10-hexamethyl-triethylenetetramine(HMTETA) initiator/catalyst complex in methanol/water mixture. Well-controlled/‘living’ behavior was demonstrated throughout the reaction, up to high monomer conversion. The PDI value remained low at 1.26 even for a polymer with very high molecular weight at 1.1×10⁶ g/mol. We believe this is the first successful case where controlled ATRP produces a polymer with molar mass exceeding a million!     

壳聚糖的接枝改性及其CO2/N2响应乳化性能研究

通过化学反应将甲基丙烯酸二甲氨基乙酯(DMAEMA)接入壳聚糖(CTS)的分子结构中,获得改性产物CTS-gDMAEMA。使用红外光谱和核磁氢谱对其进行了结构表征。向CTS-g-DMAEMA的聚集体分散液中依次通入CO_2和N_2后,其外观形态、透光率和电导率发生了明显的循环变化,证实了CTS-g-DMAEMA的CO_2/N_2刺激响应性。水-液体石蜡的乳化实验证明,与原料CTS相比,CTS-g-DMAEMA具有更好的稳定乳液的能力;并且在CO_2/N_2作用下,由CTS-g-DMAEMA制备的乳液可以发生破乳和再乳化的循环。     

原子转移自由基聚合法合成阳离子星型聚合物

β-环糊精(β-CD)经2-溴异丁酰溴酰化后合成具有多个支链的引发剂2-溴异丁酰化β-环糊精(β-CD-BIBB)。然后以丙烯酰胺(AM)和甲基丙烯酸二甲氨基乙酯(DMAEMA)为共聚单体,β-CD-BIBB为引发剂,2,2'-联吡啶(BPY)为配位剂和CuBr为催化剂,采用原子转移自由基聚合(ATRP)技术合成阳离子星型聚合物。反应温度为80℃,BPY与CuBr摩尔比一定时,聚合物的黏均相对分子质量(简称黏均分子量,下同)随着DMAEMA与β-CD-BIBB摩尔比增加而升高;在DMAEMA与β-CD-BIBB摩尔比一定时,黏均分子量随着BPY与CuBr摩尔比的增加而升高。通过FTIR、1HNMR、DSC、TG等对β-CD-BIBB和阳离子星型聚合物的结构进行了表征。     

A pH-sensitive double [60]fullerene-end-capped polymers via ATRP: Synthesis and aggregation behavior

A double [60]fullerene (C₆₀)-end-capped water-soluble polymer [C₆₀-DMAEMA₆₈-C(CH₃)₂COOCH₂]₂ was synthesized by cycloaddition of the double azido-terminated [DMAEMA₆₈-C(CH₃)₂COOCH₂]₂ with C₆₀. The well-defined [Br(Cl)-DMAEMA₆₈-C(CH₃)₂COOCH₂]₂ was first synthesized via ATRP using ethylene bis(2-bromoisobutyrate) as initiator in ethanol. TGA and spectrophotometric analyses confirmed that monoaddition to C₆₀ had occurred. In aqueous solution, [C₆₀-DMAEMA₆₈-C(CH₃)₂COOCH₂]₂ self-assembled into flower micelles. The aggregation behaviors in unbuffered distilled water and in acidic solution at pH 3 were studied by laser light scattering (LLS). The micelles formed in distilled water has an aggregation number (N_agg) of ∼242 which is about three times larger than that at pH 3 solution (N_agg = 81). However, the micellar size is bigger at pH 3, due to the highly stretched corona resulting from the charge repulsion among the protonated amino groups. After calcination, the C₆₀ core could be seen clearly by AFM. The critical micelle concentration (CMC) of [C₆₀-DMAEMA₆₈-C(CH₃)₂COOCH₂]₂ is lower in unbuffered distilled water (28.6 mg dm⁻³) than in solution at pH 3 (176.8 mg dm⁻³).