DADC/MMA共聚物的合成及性能研究

采用DSC和DMA研究了一缩二乙二醇双烯丙基碳酸酯（DADC）与甲基丙烯酸甲酯（MMA）的共聚合反应，测定了共聚物组成对树脂浇铸体力学性能的影响。结果表明：DADC与MMA的共聚树脂浇铸体加工性能良好，拉伸强度和弯曲强度都比DADC的均聚物有了明显提高，共聚物固化反应表观活化能为108kJ/mol，固化反级数n=0.94。     

网络型聚醚酯弹性体聚柠檬酸二甘醇酯的合成与性能

用一缩二乙二醇(二甘醇)和柠檬酸通过熔融缩聚的方法,合成了一种新型的网络型聚醚酯弹性体—po-ly(diethylene glycol citrate)(PDGC).用FTIR初步表征了预聚物的结构;通过ATR-FTIR、DSC、XRD等表征了PDGC的结构;测试了材料的静态水接触角、力学性能以及体外降解性能,考察了单体的摩尔比以及后期交联时间对材料上述性能的影响.     

丁二酸二(二乙二醇单甲醚)酯的制备及其应用

以二乙二醇单甲醚和丁二酸酐为原料,对甲苯磺酸为催化剂,在二甲苯中经开环反应合成了丁二酸二(二乙二醇单甲醚)酯(1),其结构经1H NMR和IR确证。采用恒电流充电法、循环伏安扫描和充放电性能测试了电解质溶液[1.2 mol·L-1双三氟甲基磺酰亚胺锂(LiTFSI)/V(1)∶V(EC)∶V(DEC)=3∶3∶4]在锂离子电池中的电化学性能。结果表明:1与石墨负极有较好的相容性,在0 V~2 V,0.1 C下充放电20次后放电比容量为346.2 mAh·g-1,容量保持率为111.10%。     

Polymerization of diethylene glycol bis(allyl carbonate) by means of di-sec-butyl peroxydicarbonate

The initial stages of the free radical polymerization of diethylene glycol bis(allyl carbonate) at temperatures of 35–65°C have been studied. The polymer is unsaturated and cyclization to give a 16-membered ring occurs only to a small extent. The kinetic order with respect to the initiator, di-sec-butyl peroxydicarbonate, has an average value of 0.79; the order increases slightly with peroxydicarbonate concentration over the range 0.018–0.22M. The molecular weight of the polymer isolated after 3% polymerization is close to 19,000. It shows no significant dependence on initiator concentration or on temperature. The dominant feature of the bulk polymerization, as in free radical polymerization of the other allyl and diallyl monomers, is degradative chain transfer in which the growing polymer radical abstracts a hydrogen atom from a monomer unit to give a relatively unreactive allylic radical. The dependence of rate on initiator concentration is rationalized if some of these allylic radicals are able to reinitiate polymerization. The transfer constant to monomer is 0.014 at 50°C, assuming that the main termination step involves mutual termination of allylic radicals. Carbon tetrachloride is an active transfer agent with a transfer constant of 0.20 ± 0.04 at 50°C. Toluene, which is less active, has a transfer constant of 0.0064 at 50°C and also retards the polymerization. Some kinetic studies have been made with other initiators, including di-2-methyl-pentanoyl peroxide which initiates polymerization at temperatures as low as 13°C.     

Degradation mechanism of diethylene glycol units in a terephthalate polymer

Diethylene glycol (DEG) is incorporated into poly(ethylene terephthalate) (PET) during industrial synthesis in order to control crystallisation kinetics. DEG is known to be a weak point in the thermal degradation of PET, which is problematic during the recycling of the polymer.Studies on the thermal decomposition of the model polymer poly(diethylene glycol terephthalate) (PDEGT) have been performed using TG, DSC, TVA and spectroscopic techniques. They revealed a degradation behaviour with two distinct steps, where the first step initiates some 100 K below the degradation temperature of PET. The second step is similar to the behaviour of PET.Based on our observations, a new degradation mechanism specific to DEG units is proposed, where random ether groups along the backbone can back-bite and form cyclic oligomers. These cyclic species, containing ether moieties, are evolved at 245 °C and constitute the first of the two steps of degradation observed for PDEGT.     

Synthesis,characterization and isothermal crystallization behavior of poly(butylene succinate)‐b‐poly(diethylene glycol succinate) multiblock copolymers

In order to modify the properties of poly(butylene succinate), poly(diethylene glycol succinate) (PDGS) segment was incorporated by chain‐extension reaction of dihydroxyl‐terminated PBS and PDGS precursors using hexamethylene diisocyanate as a chain extender to form PBS‐b‐PDGS multiblock copolymers. The chemical structure and basic physical properties of the multiblock copolyesters were characterized by nuclear magnetic resonance spectroscopy, differential scanning calorimeter (DSC), wide angle X‐ray diffraction, and tensile testing. The results suggested that the incorporation of PDGS segments would increase the elongation at break of PBS significantly while decrease its melting temperature and crystallization temperature slightly. The isothermal crystallization kinetics studied by DSC and polarized optical microscopy indicated that the crystallization rate of the multiblock polymers decreased gradually with increasing PDGS segment content while the crystallization mechanism kept unchanged and the spherulitic growth rate of the multiblock copolymers decreased gradually with increase in PDGS content due to its diluent effect to the crystallization of PBS segments. Copyright © 2015 John Wiley & Sons, Ltd.     

Viscosity of binary mixtures of 2-ethoxyethanol with ethylene glycol,diethylene glycol,triethylene glycol and tetraethylene glycol systems at T = (293.15, 298.15 and 303.15) K

Viscosities, at T = 293.15, 298.15 and 303.15 K, in the binary mixtures of 2-ethoxyethanol with ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol have been measured as a function of composition. From the experimental data the deviations in the viscosity have been calculated. The viscosity data, at T = 298.15 K, were correlated with equations of Hind et al., Grunberg and Nissan, and Frenkel. The results are discussed in terms of intermolecular interactions and structural properties of studied binary mixtures.     

聚苯乙烯负载聚乙二醇在合成碳酸亚丙酯上的应用

用金属钾、金属钠以及氢氧化钠水溶液等方法制备聚苯乙烯负载聚乙二醇，结果表明，采用金属钾比金属钢具有更好的接枝效果，并能使反应在较低的温度下较快进行。在氢氧化钠溶液中添加少量相转移剂，如Bu4NBr，接枝效果也有所提高。以聚苯乙烯负载聚乙二醇和KI一起为催化剂，研究了溶剂、温度等因素对CO2与环氧丙烷合成碳酸亚丙酯催化活性的影响。结果表明，以甲醇为溶剂催化活性较高。研究还表明，聚苯乙烯负载聚乙二醇具有较好的热稳定性，可以在150℃下重复使用至少5次。     

Activation of Supports Containing Hydroxyl Groups Using bis(4-Nitrophenyl) carbonate

Abstract

The hydroxyl groups carrying supports, Sepharose Cl-4B and Fractogel HW75F, were facilely activated under anhydrous conditions using bis(4-nitrophenyl) carbonate (BPNPC), a stable and readily available compound. The activation time at room temperature can be as short as 0.5 hour. The activated supports can be stored at 4°C for at least one month without any loss of coupling capacity. Amines can be coupled to the activated support at pH 7 to 10. Coupling of Protein A to BPNPC activated supports yielded immobilized Protein A affinity supports having a high IgG binding capacity. For example, the Protein A-Sepharose and Protein A-Fractogel prepared by using the BPNPC activation method were able to bind, respectively 13 - 14 mg and 8 - 9 mg human IgG with phosphate buffer saline as the loading buffer. In contrast the use of a high yield binding buffer increases the binding capacity of the two affinity supports to 25 - 28 mg and 22 mg respectively.     

Thermal behaviour of poly(allyl azide)

The paper describes the synthesis of low molecular mass poly(allyl chloride) (PAC) (M _n= 856-3834 g mol^-1) using Lewis acid (ALCL₃, FeCL₃, TiCL₄) and al powder. Branching in PAC was indicated on the basis of elemental analysis and ¹H-NMR spectroscopy. azidation of pac could be carried out at 100°C by using NaN₃ and DMSO as solvent. Curing of poly(allyl azide) (PAA) by cyclic dipolar addition reaction with EGDMA (ethylene glycol dimethacrylate, 5-45 phr) was investigated by differential scanning calorimetry and structure of cured polymer was confirmed by FTIR. A two-step mass loss was exhibited by uncured and cured PAA in nitrogen atmosphere. A mass loss of 20-28% (155-274°C) and 50-61% (330-550°C) was observed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Enzymatic Synthesis and Characterization of Novel Amphiphilic Triblock Copolymer Poly（p-dioxanoneco-5-benzyloxytrimethylene carbonate）-block-poly（ethylene glycol）

In recent years, amphiphilic block copolymers consisting of hydrophilic and hydrophobic segments have attracted much attention, because of their unique phase behavior in aqueous media and potential applications as drug delivery systems1. Poly(ethylene gly…     

Efficient and mild swern oxidation using a new sulfoxide and bis(trichloromethyl)carbonate

A new type of sulfoxide, 4-(2-(2-(methylsulfinyl) ethyl)-4-nitrophenyl)- morpholine (I), was designed and prepared in good yield. Upon the combination of I and bis(trichloromethyl)carbonate, the Swern oxidation of primary and secondary alcohols was significantly promoted under mild conditions, which afforded the corresponding aldehydes or ketones in good yields. It is noteworthy that the reoxidation of the isolated by-product sulfide V could be further recycled in Swern oxidation.     

磺酰脲类除草剂噻磺隆的非光气法合成

除草剂;磺酰脲类除草剂噻磺隆的非光气法合成     

F-alkylation of bis(allyl) polyoxyethylene ethers

Bis(3-F-alkylallyl) polyoxyethylene ethers were obtained via radical addition of F-alkyl iodides on bis(allyl) ethers CH₂CH(CH₂OCH₂)_nCHCH₂ followed by 1,8-diazabicyclo[5.4.0]undec-7-ne (DBU) dehydrohalogenation.     

Polyaddition of bis(seven‐membered cyclic carbonate) with diamines: A novel and efficient synthetic method for polyhydroxyurethanes

This article deals with the polyaddition of a novel bis(seven‐membered cyclic carbonate), 1,2‐bis[3‐(1,3‐dioxepan‐2‐one‐5‐yl)‐propylthio]ethane, with the diamines 4,9‐dioxa‐1,12‐dodecanediamine and p‐xylylenediamine. The polyaddition was carried out at 30–70 °C for 6–24 h in dimethyl sulfoxide to obtain the corresponding polyhydroxyurethanes with number‐average molecular weights of 10,900–35,700 in good yields. The reaction of a monofunctional seven‐membered cyclic carbonate, 5‐allyl‐1,3‐dioxepan‐2‐one (7CC), with monoamines was also carried out to examine the reactivity in comparison with that of six‐ and five‐membered cyclic carbonates. The reaction rate constants of 7CC with n‐hexylamine and benzylamine were estimated to be 48.5 and 11.0 L/mol · h, respectively, in dimethyl sulfoxide‐d₆ (initial reagent concentration = 1 M) at 30 °C. The seven‐membered cyclic carbonate ring was 2.98 and 5.82 kcal/mol more strained than those of the six‐ and five‐membered cyclic carbonates, respectively, according to a semiempirical molecular orbital calculation with the PM3 Hamiltonian. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4091–4100, 2001     

氯化聚丙撑碳酸酯增容聚丙撑碳酸酯/秸秆粉复合材料的制备及性能

聚丙撑碳酸酯(PPC)是一种新型热塑性生物降解材料,但其热性能及力学性能较差,应用受到限制。以秸秆粉这种农作物副产品作为增强体改性PPC,既可以提高PPC的力学性能同时又可开发利用秸秆资源。氯化聚丙撑碳酸酯(CPPC)是聚丙撑碳酸酯(PPC)经过氯化得到的,对天然纤维表面具有良好的浸润性和粘结性。本文以CPPC为增容剂,通过熔融共混法制备了PPC/秸秆粉复合材料。采用扫描电子显微镜(SEM)、拉伸实验、动态力学性能测试(DMA)及转矩流变仪对复合材料的结构及性能进行了表征,重点考察了CPPC的添加量对复合材料力学和流变性能的影响。结果表明,当CPPC质量分数为1.8%时,可使添加质量分数为30%秸秆粉的PPC复合材料拉伸强度提高38%,模量提高30%。同时,CPPC的引入使复合材料的粘度下降,改善了PPC/秸秆粉复合材料的加工性能。因此,作为增容剂的CPPC为制备高性能PPC/天然纤维复合材料提供了新的解决办法。     

A tetraethylene glycol dimethylether-lithium bis(oxalate)borate (TEGDME-LiBOB) electrolyte for advanced lithium ion batteries

Tetraethylene glycol dimethylether-lithium bis(oxalate)borate (TEGDME-LiBOB) electrolyte is here studied. Electrochemical impedance spectroscopy (EIS) measurements demonstrate that the electrolyte has conductivity higher than 10^− 3 S cm^− 1 at room temperature and about 10^− 2 S cm^− 1 at 60 °C, while thermogravimetry indicates a stability extending up to 180 °C. Sweep voltammetry of the electrolyte shows anodic stability extending over 4.6 V vs. Li and cathodic peak at about 1.5 V vs. Li/Li⁺, caused by a decomposition of LiBOB salt, and following prevented by using a pre-treated Sn-C anode. Furthermore, LiFePO₄ electrode is successfully used as cathode in a lithium cell using the TEGDME-LiBOB electrolyte. The promising electrochemical results, the low cost and the very high safety level candidate the electrolyte here reported as a valid alternative to the conventional electrolyte based on fluorinated salts presently used in the lithium ion battery field.     

Synthesis of novel bis(chromenes) and bis(chromeno[3,4-C]pyridine) incorporating piperazine moiety

Novel bis(2-oxo-2H-chromene) as well as bis(2-imino-2H-chromene) derivatives incorporating piperazine moiety were prepared by the cyclocondensation reaction of bis(2-hydroxybenzaldehyde) with two equivalents of each of the appropriate β-ketoesters or acetonitrile derivatives. The bis(2-imino-2H-chromene-3-carbothioamide) derivative was used as a key synthon for construction of novel bis(3-(4-substituted thiazol-2-yl)-2H-chromen-2-one) derivatives via its cyclocondensation with a series of the appropriate α-halocarbonyl derivatives. Moreover, the bis(2-hydroxybenzaldehyde) reacted with four equivalents of the appropriate acetonitrile derivatives to afford the corresponding bis(3H-chromeno[3,4-c]pyridine) derivatives. Elucidation of the structure of the novel bis(chromenes) bearing piperazine nucleus was established by the spectral data and elemental analyses.     

Micellization and Thermogelation of Poly(ether urethane)s Comprising Poly(ethylene glycol) and Poly(propylene glycol)

A series of multiblock poly(ether urethane)s comprising poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) segments were synthesized. Their aqueous solutions exhibited thermogelling behavior at critical gelation concentrations (CGC) ranging from 8 to 12 wt%. The composition and structural information of the copolymers were studied by GPC and ¹H NMR. The critical micellization concentration (CMC) and thermodynamic parameters for micelle formation were determined at different temperatures. The temperature response of the copolymer solutions were studied and found to be associated with the composition of the copolymers.