两亲性乙基纤维素接枝松香聚合物的合成及自组装

通过可逆加成断裂链转移聚合法（RAFT）将脱氢枞酸(2-甲基丙烯酰氧基异丙醇基)酯（DAGMA）单体接枝到乙基纤维素上合成了全生物质基两亲性的乙基纤维素-聚脱氢枞酸(2-甲基丙烯酰氧基异丙醇基)酯共聚物（EC-g-PDAGMA）,并制备了聚合物自组装胶束。利用核磁共振氢谱（¹H NMR）、凝胶色谱仪（GPC）对聚合物的结构进行了表征,证实成功合成了EC-g-PDAGMA。由于脱氢枞酸的引入,EC-g-PDAGMA接枝共聚物具有明显的紫外吸收性能。利用动态光散射（DLS）和透射电子显微镜（TEM）对聚合物自组装胶束的粒径、胶束溶液的Zeta电位和形貌进行了表征。结果表明,EC-g-PDAGMA共聚物在选择性溶剂THF/H₂O中能够进行自组装形成规整的球形胶束,并且其大小随着聚合物浓度和分子链长而变化,粒径分布较窄,同时胶束具有良好的储存稳定性。     

松香基紫外光固化功能单体的合成和表征

松香是一种重要可再生资源,随着石油资源的日益枯竭,将松香改性成聚合物单体重新受到关注.本文以脱氢枞酸为原料,以草酰氯为酰基化试剂(物质的量比1:1),先合成脱氢枞酸酰氯,然后再与甲基烯丙醇酯化(物质的量比1:1),合成脱氢枞酸甲基烯丙基酯,并分别采用了FT-IR、GC-MS、13C-NMR和DSC对其结构和性能进行表征.研究结果表明,所合成的脱氢枞酸烯甲基丙基酯的质量分数为91.36%,熔程为41.24～52.24℃,在引发剂的存在下可以发生聚合反应,可作为光固化树脂应用于涂料中.     

由松香合成氨基噻二唑衍生物及其抑菌活性

以松香为起始原料,经歧化、提纯得脱氢枞酸、二氢枞酸;经Diels-Alder双烯加成得丙烯海松酸和马来海松酸。4种酸与硫代氨基脲关环得到4个新型氨基噻二唑衍生物化合物。通过红外、MS、1HNMR和元素分析对产物进行了表征。采用最低抑菌浓度法对目标产物的抑菌性能进行了测试,初步的结果显示,化合物都有一定的抑菌活性,特别是化合物5-脱氢枞基-2-氨基-1,3,4-噻二唑对金黄色葡萄球菌和表皮葡萄球菌具有良好的活性,对其最低抑菌质量浓度均为4 mg/L,而且比脱氢枞酸的活性高。     

N-乙基甲基丙烯基脱氢枞酰胺的合成及表征

以歧化松香为原料,提纯得到脱氢枞酸,经酰氯化合成脱氢枞酸酰氯,再与N-乙基甲基丙烯胺发生酰胺化反应合成一种松香基丙烯胺类单体——标题化合物。通过FT-IR、GC-MS、1HNMR、13CNMR、元素分析、DSC及TG等手段表征了其结构和性能。结果表明:标题化合物的气相色谱纯度为98.63%,它在高温下可以发生聚合反应,并且以偶氮二异丁腈作为引发剂可以降低其聚合温度。标题化合物共聚物的玻璃化转变温度为-19.95℃,热分解温度为192.5~288.5℃。     

松香含氮衍生物对小地老虎四龄幼虫的拒食活性及构效关系

采用叶碟浸叶法,研究了4种不同类型的松香含氮衍生物对小地老虎4龄幼虫的拒食活性。结果显示：脱氢枞胺对氯水杨醛Schiff碱（2i）和二氢枞酸异丙醇酰基硫脲（4b）较大地抑制了小地老虎4龄幼虫的取食,质量浓度1 g/L时2i和4b 24 h后的拒食率分别为86.12%和85.13%;脱氢枞胺对甲氧基苯甲醛Schiff碱（2b）、二氢枞酸2-羟甲基-1,3-丙二醇酰基硫脲（4c）和二氢枞酸呋喃酰基硫脲（4g）对小地老虎4龄幼虫具有较强的拒食活性,拒食率分别为52.04%、66.70%和50.48%。2i具有极低的拒食中质量浓度（AFC₅₀）,为0.04 g/L,2b、4b、4c和4g的AFC₅₀分别为0.66、0.25、1.47和0.69 g/L。脱氢枞胺（取代）苯甲醛Schiff碱和二氢枞酸酰基硫脲2类衍生物对小地老虎具有较强的拒食活性,甲氧基、氯原子和羟基对脱氢枞胺（取代）苯甲醛Schiff碱的拒食活性有明显的增强作用,二氢枞酸酰基硫脲衍生物中羟基的位置和个数对小地老虎4龄幼虫的拒食活性有明显的影响。脱氢枞酸酰胺和脱氢枞酸酰基硫脲衍生物对小地老虎4龄幼虫的拒食活性较弱,且其结构变化对小地老虎4龄幼虫的拒食活性影响较小。     

新型脱氢松香酰肼基硫脲的研究

以松香改性产品脱氢枞胺为原料,乙醚为溶剂,在-10～40℃下与二硫化碳(CS2)、N,N'-二环己基碳二亚胺(DCC)作用,合成脱氢松香异硫氰酸酯,最高产率为84.1%。然后以对甲苯磺酰氯、苯磺酰氯、水合肼为原料,四氢呋喃为溶剂,在10～15℃下分别合成对甲苯磺酰肼(最高产率91.9%)和苯磺酰肼(最高产率96%)。最后,松香异硫氰酸酯分别与对甲苯磺酰肼、苯磺酰肼反应,乙醇为溶剂,于60～80℃条件下回流搅拌,合成了対甲苯磺酰肼基脱氢枞氨基硫脲和苯磺酰肼基脱氢枞氨基硫脲,最大收率均大于60%。所合成的化合物经红外光谱、核磁共振谱等表征分析,证实是一种未见报道的新化合物。     

脱氢枞基含氮衍生物的抑菌活性研究

采用平板计数法研究了脱氢枞酸（1）和脱氢枞基含氮衍生物（脱氢枞胺（2）、脱氢枞酸酰胺衍生物（3a~3m）、脱氢枞胺（取代）苯甲醛Schiff碱衍生物（4a~4i））对6种病原真菌的抑制活性。结果表明：脱氢枞胺的抑菌活性优于脱氢枞酸,脱氢枞胺（取代）苯甲醛Schiff碱衍生物的抑菌活性优于脱氢枞酸酰胺衍生物。其中含卤原子的脱氢枞胺（对氯）水杨醛Schiff碱（4d）、脱氢枞胺（间氟）苯甲醛Schiff碱（4f）、脱氢枞胺（对氟）苯甲醛Schiff碱（4g）、脱氢枞胺（对氯）苯甲醛Schiff碱（4h）具有较强的抑菌活性,4h在质量浓度为180 mg/L时对灰葡萄孢、腐皮镰孢和芸苔链格孢的抑制率达100%,抑制率接近阳性对照物放线菌酮。进一步测定了脱氢枞胺（取代）苯甲醛Schiff碱衍生物4d、4f、4g和4h在不同质量浓度下对6种病原真菌的抑菌活性。结果发现4种化合物在不同质量浓度下对灰葡萄孢和芸苔链格孢均具有较好的抑制活性。化合物4f在22.5 mg/L时对6种病原真菌的抑制率最高,均大于95%,而4g在22.5 mg/L时的抑制率却最低,并且4h在45 mg/L时的抑制率较高,上述结果表明苯环上卤原子的取代位置和类型均会影响其在不同质量浓度下的抑菌活性和最佳抑菌活性的质量浓度。     

含松香骨架甜菜碱类两性表面活性剂的合成

以脱氢枞酸为原料,合成了3种新型含松香骨架的甜菜碱类表面活性剂:N-(2-脱氢枞酰氧基)乙基-N,N-二甲基羧甲基甜菜碱,N-(2-脱氢枞酰氧基)乙基-N,N-二甲基磺丙基甜菜碱和N-(2-脱氢枞酰氧基)乙基-N,N-二甲基磷酸酯甜菜碱。通过红外和核磁共振氢谱对产物结构进行表征,3种甜菜碱cmc分别为3.16 mmol.L-1、3.01 mmol.L-1和2.56 mmol.L-1,此时表面张力分别为31.91 mN.m-1、33.20 mN.m-1和25.79 mN.m-1,说明3种甜菜碱具有好的表面活性。     

脱氢枞酸(β-丙烯酰氧基乙基)酯的合成和表征

以脱氢枞酸为原料,以草酰氯为酰基化试剂(摩尔比1∶1),先合成脱氢枞酸酰氯,然后再与丙烯酸-β-羟基乙基酯酯化(摩尔比1∶1),合成脱氢枞酸(β-丙烯酰氧基乙基)酯,得率75%,质量分数98.5%。用FTIR、GC-MS、13CNMR和DSC对其结构和性能进行了表征。结果表明,脱氢枞酸(β-丙烯酰氧基乙基)酯是一种熔点为59~61℃的白色晶体,在引发剂的存在下,可以发生聚合反应,均聚物玻璃化转变温度约为54.2℃。     

黄原酸酯调控的氯乙烯的可逆-加成断裂链转移聚合

以三种不同结构的黄原酸酯为调控剂,进行氯乙烯（VC）溶液和细乳液可逆加成-断裂链转移（RAFT）聚合,发现O-乙基黄原酸丙酸乙酯对VC聚合的调控效果良好,氯乙烯RAFT细乳液聚合速率明显大于溶液聚合,VC聚合12 h转化率大于90%,但聚氯乙烯（PVC）的分子量分布宽于溶液聚合产物。核磁共振和紫外可见吸收光谱分析证明合成的PVC具有黄原酸酯基端基结构,结构缺陷少。含黄原酸酯基PVC可进一步调控VC及醋酸乙烯酯聚合,进行扩链或得到嵌段共聚物。结合聚合动力学,说明黄原酸酯调控的氯乙烯聚合具有活性特征。     

Synthesis and Characterizations of Triphenylamine End-Functionalized Polymers via Reversible Addition-Fragmentation Chain Transfer Polymerization

A novel reversible addition-fragmentation chain transfer (RAFT) reagent bearing triphenylamine (TPA) group, 4-diphenylamino-dithiobenzoic acid benzyl ester (DDABE), was designed and synthesized. It was used in the RAFT polymerizations of styrene (St) and methyl acrylate (MA) to prepare end-functionalized polymers. The results of the polymerization showed that the RAFT polymerizations could be well controlled using DDABE as the RAFT agent. Number-average molecular weight (M_n,GPC) increased linearly with monomer conversion, and molecular weight distributions were relatively narrow (PDI< 1.50). The results of chain-extension reaction, ¹H NMR spectra and UV/Vis spectra confirmed that most of the polymers chains were end-capped by the functional triphenylamine (TPA) groups. The effect of feed molar ratios of St/DDABE/AIBN on polymerization was investigated.     

Synthesis of chemically amplified photoresist polymer containing four (Meth)acrylate monomers via RAFT polymerization and its application for KrF lithography

KrF photoresist polymers (PASTMs) were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization. Four (meth)acrylates with lithographic functionalities including styrene (St), 4-acetoxystyrene (AST), 2-methyl-2-adamantyl methacrylate (MAMA), and tert-butyl acrylate(TBA) were used as monomer components and 2-methyl-2-[(dodecylsulfanylthiocarbonyl) sulfanyl]propanoic acid (MDFC) was used as RAFT agent, varying the RAFT content could modulate molecular weight. Fourier-transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (¹H NMR) indicated that the synthesis was successful. Gel permeation chromatography (GPC) showed that the molecular weight decreased with the increased content of MDFC, and all the polymers possessed weight-average molecular weight below ten thousand and polydispersity less than 1.32. Thermogravimetric analysis (TGA) characterized the thermal properties, the results implied that initial thermal decomposition temperature reached 200 °C, which could satisfy the lithography process. Differential scanning calorimetry (DSC) showed that the Tg decreases with molecular weight. The RAFT polymerization kinetics plots demonstrated that the polymerization was first-order, the number-average molecular weights of the polymers with relatively low polydispersity index values increased with total monomer conversions indicating that the concentration of growing radicals was constant throughout the polymerization process. The narrow molecular weight distribution and composition uniformity of the polymers prepared by RAFT polymerization could be beneficial for lithography, after alcoholysis, lithography evaluation under KrF lithography showed that this homogeneous polymer photoresist exhibited better space and line (S/L) pattern with resolution of 0.18 μm according to the SEM image.     

RAFT miniemulsion polymerization of methyl methacrylate

It has been well documented that RAFT miniemulsion polymerization has broader molecular weight distribution, compared with its bulk polymerization counterpart. Interestingly, it was found that the PDI value of RAFT miniemulsion polymerization of methyl methacrylate (MMA) mediated by 2-cyranoprop-2-yl dithiobenzoate (CPDB) was still as low as its corresponding bulk polymerization did. PDI could be as low as 1.13 even with typical sodium dodecyl sulfate (SDS, 1 wt%, surfactant) and n-hexadecane (HD, 2 wt%, costablizer) concentrations. When the polymerization was carried out at 60 °C, a dramatic increase in PDI (>1.4) was observed after 80% monomer conversion since RAFT addition reaction became diffusion-controlled. Increasing the polymerization temperature to 80 °C could reduce the PDI to 1.2 even at 100% monomer conversion. The compartmentalization effect of radicals was surprisingly absence before 30% monomer conversion but became pronounced afterwards in the miniemulsion polymerization. Thus, it still took less time to finish the miniemulsion polymerization with the increase of the surfactant levels.     

Comparison of RAFT polymerization of methyl methacrylate in conventional emulsion and miniemulsion systems

In this study, we have conducted the reversible addition-fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) in two heterogeneous systems, i.e. conventional emulsion and miniemulsion, with identical reaction conditions. The main objective is to compare the living character in both systems according to the nucleation mechanism, the latex stability, the particle sizes and particle size distributions of latexes, the molecular weights and molecular weight distributions (or polydispersity index, PDI) of PMMA, and the kinetics of the RAFT polymerization. The RAFT agent used in both systems was 2-cyanoprop-2-yl dithiobenzoate (CPDB). The effects of an oil-soluble initiator 2,2′-azobisisobutyronitrile (AIBN) and a water-soluble initiator kalium persulfate (KPS) on the RAFT/emulsion and RAFT/miniemulsion polymerizations were investigated. Methyl-β-cyclodextrin (Me-β-CD) was used as a solubilizer. The average molecular weights and molecular weight distributions (PDIs) of dried PMMA samples were characterized by gel permeation chromatography (GPC). The experimental results showed that the RAFT/miniemulsion polymerization of MMA exhibited better living character than that of RAFT/emulsion polymerization under the conditions of our experiment. The PDI of PMMA in RAFT/miniemulsion polymerization was decreased with the addition of Me-β-CD. However, Me-β-CD did not have influence on the PDI of PMMA prepared in RAFT/emulsion polymerization.     

Reversible addition-fragmentation chain transfer polymerization of 7-(4-(acryloyloxy)butoxy)coumarin

The light sensitive vinyl monomer with coumarin unit, 7-(4-(acryloyloxy)butoxy)coumarin (7AC), was synthesized. The reversible addition-fragmentation chain transfer (RAFT) polymerization of 7AC, initiated by 2,2′-azobisisobutyronitrile (AIBN), was carried out using 2-cyanoprop-2-yl dithiobenzoate (CPDB) as a RAFT agent in N,N-dimethylformamide (DMF) solution. The kinetics exhibited first-order relationship with respect to the monomer concentration. The molecular weight of the polymer increased linearly with the monomer conversion. The chain extension of poly(7-(4-(acryloyloxy)butoxy)coumarin) (P7AC) using styrene (St) as the second monomer demonstrated that the obtained polymers were almost “living”. The fluorescence intensity of P7AC increased with the molecular weight of P7AC and was stronger than that of the monomer. The obtained polymer had strong ultraviolet (UV) absorption at 322 nm. The molecular weights of the polymer had no effect on its ultraviolet absorption intensity. The coumarin structure existing in P7AC underwent [2 + 2] cycloaddition reaction (photodimerization) under UV irradiation in tetrahydrofuran (THF) solution, which can be further used to prepare small particles from the single polymer.     

Reversible addition fragmentation chain transfer polymerization of 3-[tris(trimethylsilyloxy) silyl] propyl methacrylate

Reversible addition fragmentation chain transfer (RAFT) bulk polymerizations of 3-[tris(trimethylsilyloxy)silyl] propyl methacrylate (TRIS) have been carried out at 60 °C, employing cumyl dithiobenzoate (CDB) and 2-cyanoprop-2-yl dithiobenzoate (CPDB) as mediating agents at concentrations ranging from 5.0×10⁻³ to 2.0×10⁻² mol l⁻¹. The monomer conversion vs. time evolution was followed via dilatometry and ¹H NMR spectroscopy. The CDB mediated polymerization displays RAFT agent concentration dependent inhibition and rate retardation phenomena, whereas the CPDB mediated polymerization process is less susceptible to rate retardation and inhibition effects. The different behavior of CDB and CPDB in TRIS polymerization is most likely due to the increased stability of the intermediate macroRAFT radicals in the CDB mediated process. The generated RAFT polymers were analyzed via size exclusion chromatography indicating linear macromolecular growth with respect to monomer conversion and low polydispersities (PDI<1.15) up to high monomer to polymer conversion (>90%).     

“Living”/controlled polymerization of methyl acrylate mediated by dithiocarbamates under γ‐ray irradiation

γ‐Ray initiated reversible addition–fragmentation chain transfer (RAFT) polymerizations of methyl acrylate (MA) were investigated in bulk using five different dithiocarbamate structures, 2‐phenyl‐benzoimidazole‐1‐carbodithioic acid benzyl ester ( 1b ), 2‐methyl‐benzoimidazole‐1‐carbodithioic acid benzyl ester ( 1c ), 2‐pheny‐indole‐1‐cardithioic acid benzyl ester ( 1d ), 2‐(carbazole‐9‐carbothioylsulfanyl)‐2‐methyl‐propionic acid ester ( 1e ), and carbazole‐9‐carbodithioic acid naphthalene‐1‐ylmethyl ester ( 1f ), as RAFT agents. The experiment results showed that MA polymerized in a controlled way under a low irradiation dose rate, i.e., first‐order kinetic plots, the experimental molecular weights increased linearly with monomer conversions. The polydispersity indices of polymers generally remained at a relatively low value (lower than 1.4). The effect of irradiation dose on the polymerization results was investigated. The obtained polymers were characterized with ¹H NMR and GPC. Chain‐extension reaction was also successfully carried out using the obtained polymer as the macro‐RAFT agent and styrene as the second monomer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1769–1775, 2007     

A new selenium-based RAFT agent for surface-initiated RAFT polymerization of 4-vinylpyridine

A new selenium-based reversible addition-fragmentation chain transfer (RAFT) agent, 4-cyanopentanoic acid diselenobenzoate (RAFT-Se), was synthesized and utilized in the surface-initiated RAFT polymerization of 4-vinylpyridine (4VP) on silicon substrate. The results indicate that the RAFT-Se can control the surface-initiated RAFT polymerization, as evidenced by the number-average molecular weight that increase linearly with monomer conversion, molecular weights that agreed well with the predicted values, and the relatively low polydispersity indexes. The surface-initiated RAFT polymerization with the RAFT-Se was the same polymerization mechanism as its analog, 4-cyanopentanoic acid dithiobenzoate (RAFT-S). The grafting density of the poly(4-vinylpyridine) brushes prepared in the presence of RAFT-Se (σ_RAFT-Se) and RAFT-S (σ_RAFT-S) was estimated to be about 0.51 and 0.66 chains/nm², respectively. In addition, the end of polymer chains on silicon substrate contains selenium element which may be useful in biosensor applications.     

Synthesis and characterization of diethyl-dithiocarbamic acid 2-[4-(2-diethylthiocarbamoylsulfanyl-2-phenyl-acetyl)-2,5-dioxo-piperazin-1-yl]-2-oxo-1-phenyl-ethyl ester as new reversible addition-fragmentation chain transfer agent for polymerization of ethyl methacrylate

Diethyl-dithiocarbamic acid 2-[4-(2-diethylthiocarbamoylsulfanyl-2-phenyl-acetyl)-2,5-dioxo-piperazin-1-yl]-2-oxo-1-phenyl-ethyl ester as a novel di-functional reversible addition–fragmentation chain transfer (RAFT) agent was synthesized based on 2,5-diketopiperazine. The RAFT agent was designed based on the propagating core (R group) approach and characterized by ¹H NMR, ¹³C NMR, FT-IR, elemental analysis, and melting point technique. Then, ethyl methacrylate was synthesized via free radical and RAFT polymerizations. To investigate the effect of the RAFT agent on the kinetic of polymerization, molecular weight, and polydispersity index (PDI) of polymers and also monomer conversion were monitored. Also, synthesized polymers were characterized by ¹H NMR, ¹³C NMR, FT-IR, and TGA. Characterization analyses of synthesized RAFT agent were consistent with the structure. NMR and FTIR analyses confirmed end group incorporation of RAFT agent into polymer structure. According to results, poly(ethyl methacrylate) with low PDI (1.14) was obtained. Kinetic study indicated well-controlled polymerization of ethyl methacrylate by synthesized RAFT agent. TGA results showed that RAFT agent could reduce termination reactions and so reduce head-to-head bonds and chain-end unsaturation by keeping the concentration of radicals low enough.     

Controlled synthesis of sulfonated block copolymers having thermoresponsive property by RAFT polymerization of vinyl sulfonate esters

Four vinyl sulfonate ester derivatives, methyl ethenesulfonate (MES), ethyl ethenesulfonate (EES), 2,2,2-trifluoroethyl ethenesulfonate (TFES), and 2,2,2-trichloroethyl ethenesulfonate (TCLES), which are protected forms of vinyl sulfonic acids, were polymerized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Polymers having relatively narrow molecular weight distributions and pre-determined molecular weights were obtained by the polymerization of all monomers using a suitable xanthate-type chain transfer agent (CTA). The RAFT polymerizations of EES and TCLES were found to proceed in controlled fashions under suitable conditions, as confirmed by the formation of narrow polydispersity products, molecular weights controlled by the monomer/chain transfer agent ratio, and linear increases in molecular weight with conversion. Deprotection of the ethyl group of poly(EES) by LiBr in refluxing 2-butanone proceeded smoothly to give water-soluble poly(lithium vinyl sulfonate). Poly(potassium vinyl sulfonate) was also obtained by the deprotection of poly(TCLES) using potassium tert-butoxide. The syntheses of thermoresponsive block copolymers involving poly(lithium vinyl sulfonate) segments were conducted by RAFT polymerization of N-isopropylacrylamide using poly(EES) macro-CTA, followed by deprotection. The thermally-induced phase separation behavior and assembled structures of the block copolymers were also studied in aqueous solution.