Synthesis of substituted polymethylenes by radical polymerization of N,N,N′,N′-tetraalkylfumaramides and their characterization

Radical polymerization of N,N,N′,N′-tetraalkylfumaramides (TRFAm) bearing methyl, ethyl, n-propyl, isopropyl, and isobutyl groups as N-substituents (TMFAm, TEFAm, TnPFAm, TIPFAm, and TIBFAm, respectively) was investigated. In the polymerization of TEFAm initiated with 1,1′-azobiscyclohexane-1-carbonitrile (ACN) in benzene, the polymerization rate (R_p) was expressed as follows: R_p = k [ACN]^0.28 [TEFAm]^1.26, and the overall activation energy was 102.1 kJ/mol. The introduction of a bulky alkyl group into N-substituent of TRFAm decreased the R_p in the following order: TMFAm > TEFAm > TnPFAm > TIBFAm > TIPFAm ～ 0. The relative reactivities of these monomers were also investigated in radical copolymerization with styrene (St) and methyl methacrylate (MMA). In copolymerization of TRFAm (M₂) with St (M₁), monomer reactivity ratios were determined to be r₁ = 1.07 and r₂ = 0.20 for St–TMFAm, and r₁ = 1.88 and r₂ = 0.11 for St–TEFAm, from which Q₂ and e₂ values were estimated to be 0.35 and 0.44 for TMFAm, and 0.19 and 0.47 for TEFAm, respectively. The other TRFAm were also copolymerized with St, but copolymerization with MMA gave polymers containing a small amount of TRFAm units. The polymer from TRFAm consists of a less-flexible poly(N,N-dialkylaminocarbonylmethylene) structure. The solubility and thermal property of the polymers were also investigated.     

用于锂离子电池的凝胶聚合物电解质的制备与性能

以丙烯腈(AN)、丙烯酸甲酯(MA)和衣康酸锂(IALi)为自由基共聚反应的主要单体, 采用溶液聚合方法, 合成轻度交联的P(AN-MA-IALi)聚合物电解质膜.通过FTIR, DSC和SEM等测试方法对共聚物的结构进行了表征, 利用交流阻抗等电化学方法对该膜的导电性能进行了研究.实验结果表明, 所制备的交联聚合物的室温电导率达到10-5~10-4 S/cm, 当IALi的质量分数为3%时, 所制备的聚合物电解质膜的电导率最大可达到1.89×10-4 S/cm.     

有序介孔有机金属 Pd(II) 的制备及其催化水介质中的 Suzuki 反应

 以有机金属 Pd 硅烷和乙基桥联硅烷为混合硅源, 在表面活性剂作用下进行共缩聚反应, 制备了有序介孔有机金属 Pd(II) 催化剂 Pd(II)-PMO(Et). 采用傅里叶变换红外光谱、核磁共振谱、X 射线衍射、透射电子显微镜和 N2 吸附脱附等手段对催化剂进行了表征. 结果表明, 与后嫁接法相比, 共聚法制得的催化剂活性位分散均匀, 孔道不易堵塞, 同时乙基修饰的孔壁增强了催化剂表面疏水性, 有利于反应物在孔道内的扩散和吸附. 在水介质 Suzuki 反应中, Pd(II)-PMO(Et) 的催化活性与均相催化剂 Pd(PPh3)2Cl2 的相当, 且可重复使用.     

羧酸稀土配合物共聚反应的研究

通过沉淀法和直接法制备羧酸稀土配合物，与丙烯酸等单体共聚反应制备不同稀土含量的稀土有机高分子离聚物。用微量热天平(TG)、差热分析仪(DTA)等分析它的热稳定性以及玻璃化转变温度，用红外光谱分析其结构。讨论了用不同方法合成的稀土配合物对共聚反应和聚合物性能的影响。结果显示直接合成羧酸稀土配合物有利于共聚物性能的稳定和稀土含量的调节。     

Fabrication of Fluoropolymer Microtubes via RAFT Copolymerization of N,N′‐Methylene Bisacrylamide Gel Fibers and Fluoromonomer

Fluoropolymer microtubes with a smooth surface were fabricated in more than 70 % yield via reversible addition fragmentation chain transfer (RAFT) co‐polymerization of N,N′‐methylene bisacrylamide (MBA) gel fibers as both template and monomer, 2‐(perfluoro‐3‐methylbutyl)ethyl acrylate (R‐3420) as co‐monomer, and pentaerythritol tetraacrylate (PET4A) as cross‐linker. The resulting fluoropolymer microtubes were characterized fully by SEM, TEM, EDS, XPS, and FT‐IR. The influence of the monomer composition on the yields and morphologies of the tubes were investigated in detail. The results indicated that polymer microtubes with a smooth surface were obtained at suitable amounts of R‐3420 and PET4A. Because of the decreased solubility of MBA gel fibers, the wall thickness increased as more R‐3420 was used. In the presence of PET4A, the solution polymerization could be facilitated and more R‐3420 could be attached onto the tubes based on FT‐IR analysis. The water contact angle and swelling ratio measurements both revealed the low hydrophilicity and high lipophilicity of the fluoropolymer microtubes, which made the sample able to absorb toluene selectively in a water/toluene two‐phase system.     

Static ToF-SIMS analysis of plasma chemically deposited ethylene/allyl alcohol co-polymer films

A plasma co-polymerization of ethylene as a “chain extending” monomer and allyl alcohol as a carrier monomer for hydroxyl groups was studied. The composition of the feed gas was systematically varied and the plasma co-polymers were analyzed in terms of their relative concentrations of OH functional groups by static Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) immediately after their preparation without any air contact, i.e., under so called “in situ” conditions.The relative OH group concentration involved in the -CH₂-OH groups was derived from the normalized yields of the CH₃O⁺ secondary fragment ion. The density of functional groups in the plasma co-polymers was found to vary non-linearly with respect to the mole percentage of the monomers in the feed gas.Co-polymerization phenomena, i.e. chemical interactions and recombination reactions taking place between monomer molecules in the plasma and/or during the deposition process, become evident in ToF-SIMS spectra.     

脂环族环氧树脂和螺环原碳酸酯的光引发正离子共聚合

<正> 无收缩单体-1,6,8,13-四氧螺[7,7]十三碳烷(SOC_7)和3,4-环氧基环己烷甲酸3',4'-环氧基环己烷甲酯(ERL-4221)的光引发正离子共聚合的研究结果表明,少量SOC_7加到ERL-4221体系中可抑制固化收缩没有明显降低热性能。ERL-4221对SOC_7的合适克分子比为4比1,由此得到T_g为203℃而聚合时体积收缩为4.4％的交联共聚物。     

Synthesis of densely branched poly(methyl methacrylate)s via ATR copolymerization of methyl methacrylate and ethylene glycol dimethacrylate

Densely branched poly(methyl methacrylate)s have been synthesized by copolymerization of methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) using atom transfer free radical polymerization (ATRP). By employing the phenyl and benzyl esters of 2-bromo-2-methylpropionic acid as the initiators with 2,2-bipyridyl and Cu(I)Cl it has been possible to use high field ¹H nuclear magnetic resonance spectroscopy to evaluate in some detail the composition and structure of the branched PMMAs obtained. Parallel molar mass size exclusion chromatographic analysis using a multi-angle light scattering detector with a refractive index detector (MALS/SEC) has allowed the branched architecture of the products to be confirmed. Rather remarkably, high yields of branched PMMAs can be obtained without crosslinking using MMA/EGDMA molar feed ratios of up to 5/1 by appropriate adjustment of the molar feed of initiator. In particular by maintaining the EGDMA/initiator molar feed ratio ∼1/1 fully soluble products can be obtained that are densely branched since this feed ratio ensures that on average each living primary chain initiated contains on average only one branching EGDMA segment. As might be expected this controlled free radical process offers better control in the synthesis of branched polymer than the corresponding system we have reported using conventional free radical polymerization, and unlike the latter which requires the use of a chain transfer agent, the ATRP system requires no additional chain regulating component. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2375–2386, 2007     

Quantitative NMR Spectroscopy and Determination of Polymer Microstructure of Ethylene-Styrene and Ethylene-Isobutylene Co-Polymers

Summary: Quantitative ¹³C NMR spectroscopy is used to determine reactivity ratios and end group and branching frequency of ethylene-styrene and ethylene-isobutylene co-polymers synthesized at a temperature T = 205 °C and pressure p = 1650 bar at different levels of co-monomer fraction. In the forefront of the studies quantitative ¹³C NMR conditions have to be investigated. Optimum conditions are achieved using a relaxation agent Chromium(III) acetylacetonate (Cr(acac)₃) at measurement temperature T = 100 °C and a delay time d₁ = 7 s with a 90° pulse and inverse-gated decoupling. The analysis of conversion dependence of co-monomer content shows an increase in conversion with increasing co-monomer content for the ethylene-styrene co-polymerization, whereas conversion decreases with rising isobutene fraction in the co-polymer. Reactivity ratios for ethylene-styrene as well as for ethylene-isobutylene co-polymerization system are determined with values r_ES = 0.09 ± 0.007 and r_SE = 2.3 ± 7.0 and r_EIB = 3.3 ± 0.6 and r_IBE = 6.3 ± 4.2. Frequency on methyl end groups, end-of-chain contributions caused by transfer to propionic aldehyde and butyl branches are gained. For the ethylene-styrene co-polymer system a decrease in frequency is observed, whereas for the ethylene-isobutylene co-polymer system the opposite occurs. Influence of the co-monomers on the polymerization reaction steps as transfer to chain transfer agent and backbiting reaction is discussed.     

Nickel complexes bearing different electron groups on substituted salicylaldnaphthylmethyleneimine ligands: Syntheses and their catalytic performance for (co)polymerization of norbornene

Novel nickel complexes bearing different electron groups on substituted salicylaldnaphthylmethyleneimine ligands, bis-(salicylaldnaphthylmethyleneimino)Ni(II) (Ni{(3-R¹)(5-R²)C₆H₂(O)CH[N (naphthyl-CH₂)]}₂ Ni1 : R¹ = H, R² = H; Ni2 : R¹ = H, R² = CH₃; Ni3 : R¹ = H, R² = Br; Ni4 : R¹ = H, R² = OCH₃; Ni5 : R¹ = CH₃, R² = H; Ni6 : R¹ = Br, R² = H), were synthesized. Ni2 , Ni3 , Ni5 , and Ni6 are clearly characterized by single-crystal X-ray diffraction. Co-polymerization of norbornene (NB) with 5-norbornene-2-methylene butyl ether (BN) was carried out in toluene with the aforesaid complexes as catalyst precursors and B(C₆F₅)₃ as the co-catalyst. Catalyst activity, molecular weight, thermal stability, solubility, regularity, and optical transparency were investigated, and the mechanism of the electron groups changing catalyst performance is explained. All catalysts show high activity toward co-polymerization (up to 3.53 × 10⁵ g_polymer mol_Ni⁻¹ h⁻¹). Ni3 shows the highest activity and Ni5 shows the highest insertion rate (up to 37.6%). The obtained poly(NB-co-BN)s are confirmed to be vinyl-addition-type co-polymers, and they are noncrystalline. The co-polymers exhibited excellent thermal stability and processability (T_d ≥ 400 °C, T_g < 240 °C), optical transparency (up to 90%), and good solubility.