Determination of the solubility parameter of poly(ethylene oxide) at 25°C by gas-liquid chromatography

The solubility parameter of poly(ethylene oxide) at 25°C has been determined using the method developed by DiPaola-Baranyi and Guillet, by the extrapolation of the values of the interaction parameter χ, at high temperatures, ranging from 70°–90°, 90°–110° and 110°–130°C down to 25°C. The values of the solubility parameter obtained, depending on the temperature ranges employed, are 9.8, 9.9 and 10.1, respectively.     

Direct ethoxylation of fatty methyl ester over Al-Mg composite oxide catalyst

For the purpose of estimating the reaction mechanism of the direct ethoxylation of a fatty ester in the presence of an Al-Mg composite oxide catalyst, a labeled fatty methyl ester C₁₁H₂₃CO¹⁸OCH₃ containing ¹⁸O isotope was synthesized and directly ethoxylated. The product was evaluated by gas chromatography-mass spectrometry (GC-MS). The GC-MS spectra showed that the ¹⁸O isotope label was present only in the methoxy group at the molecular end of the ethoxylated fatty methyl ester. This supports the reaction mechanism of coordination anionic polymerization where the bond between the acyl and methoxy groups of the fatty methyl ester molecule was broken, caused by the bifunctional effect of the acid-base active sites; an intermediate chemisorption species was formed; and then ethylene oxide was addition-polymerized sequentially, in parallel.     

一种高度炼化一体化的乙烯发展方案

简要介绍了三种炼化一体化新技术,由此提出了一种高度炼化一体化的乙烯发展方案,与常规的炼化一体化方案进行了对比分析,表明该方案的乙烯原料更加优质且轻质化,其丙烯/乙烯比可达1.1以上。     

对我国乙烯工业发展的几点思考

阐述了世界乙烯工业现状、发展特点以及新型工艺技术分析，重点对我国乙烯工业总体发展水平、生产、消费、进出口贸易作了详细的讨论。在此基础上对我国乙烯工业发展方向、方式和规划提出了建议。     

PET/MFMB复合材料的力学性能、热性能的研究

用力学性能测定、DSC和熔体流动速率（MFR）测定法研究聚对苯二甲酸乙二酯／多功能母料（PET／MFMB）复合材料的力学性能和热性能。结果表明，当MFMB的含量为22％时，PET／MFMB复合材料的冲击强度、断裂伸长率分别出现极大值；复合材料中PET、PP的熔点比纯PET、纯PP的稍有降低，当PET／MFMB＝78／22时降低的幅度稍大；复合材料的MFR在PET／MFMB＝78／22时出现转变点。     

IR study of the interaction of hydroxyl groups of silica gel with Cr species of Phillips' type catalysts

Spectroscopic evidence for the interaction of hydroxyl groups and chromium ions was obtained using a catalyst prepared from chromyl chloride. A new OH peak, observed at 3705 cm^–1 after pumping away CO gas, is attributed to the direct interaction of OH with the low-valent chromium. This peak shifts to 3590 cm^–1 on contact with O₂ at room temperature and it is assigned to a hydroxyl interacting with the oxidized chromium. New assignments are also proposed for IR bands of CO presorbed on the catalyst. The peak due to CO at 2188 cm^–1 decreases as the OH intensity at 3705 cm^–1 increases, suggesting that the former peak arises from adsorption on Cr(II) species to which two oxygen atoms are attached.     

高效乙烯聚合催化剂的制备——I．催化剂的制备规律

研究了新型含镁络合物的结构、性质及其用于制备高效乙烯聚合催化剂的制备规律。结果表明：将镁、有机醇以及不与镁发生“格式反应”的卤代烷相互作用可迅速发生反应形成新型含镁络合物溶液。该络合物在溶液中可析出结晶。具有特定的化学结构．可以均匀承载于多孔硅胶的孔隙中，负载TiCl4后制备出形态良好的球形高效乙烯集合催化剂。     

Synthesis, characterization and properties of chitosan modified with poly(ethylene glycol)-polydimethylsiloxane amphiphilic block copolymers

Synthesis of poly(ethylene glycol)-polydimethylsiloxane amphiphilic block copolymers is discussed herein. Siloxane prepolymer was first prepared via acid-catalyzed ring-opening polymerization of octamethylcyclotetrasiloxane (D₄) to form polydimethylsiloxane (PDMS) prepolymers. It was subsequently functionalized with hydroxy functional groups at both terminals. The hydroxy-terminated PDMS can readily react with acid-terminated poly(ethylene glycol) (PEG diacid) to give PEG-PDMS block copolymers without using any solvent. The PEG diacid was prepared from hydroxy-terminated PEG through the ring-opening reaction of succinic anhydride. Their chemical structures and molecular weights were characterized using ¹H NMR, FTIR and GPC, and thermal properties were determined by DSC. The PEG-PDMS copolymer was incorporated into chitosan in order that PDMS provided surface modification and PEG provided good water swelling properties to chitosan. Critical surface energy and swelling behavior of the modified chitosan as a function of the copolymer compositions and contents were investigated.     

密度泛函方法的ZSM-5分子筛上苯与乙烯烷基化反应机理研究

采用密度泛函(DFT)方法对于ZSM-5分子筛上苯与乙烯的烷基化反应机理进行研究。选取了包含酸性质子的8T原子簇模型代表ZSM-5分子筛的部分结构。采用B3LYP/6-31G(d)水平从生成能与反应活化能角度对于烷基化反应发生时可能存在的2种联合机理和一种分步机理进行了计算与比较。结果表明,联合反应机理中乙烯的质子化和C-C键的形成同时发生,而分步机理开始于乙醇盐中间体的生成,随后与苯反应生成反应产物。分步机理中乙醇盐中间体生成步骤的活化能(124.55 kJ/mol)低于联合机理的反应活化能(168.98 kJ/mol和156.06 kJ/mol),而烷基化步骤的活化能(209.35 kJ/mol)高于联合机理的反应活化能,由此可以推断ZSM-5分子筛上苯与乙烯的烷基化反应时2种机理同时发生,存在竞争关系。     

PE-LLD／EVA／Mg（OH）2／复合阻燃剂高效无卤阻燃体系的研究

采用线形低密度聚乙烯/乙烯-醋酸乙烯共聚物作为复合材料主体,表面处理过的氢氧化镁(Mg(OH)2)为主阻燃剂,以微胶囊化红磷和自制硅类阻燃剂为核心的复合阻燃剂为阻燃增效剂,重点探讨了Mg(OH)2和复合阻燃剂的阻燃效果。结果表明,Mg(OH)2与复合阻燃剂并用具有良好的协同效应,当Mg(OH)2用量40份,复合阻燃剂5～7份时,可获得较高的氧指数,垂直燃烧试验通过FV0级,且材料抗静电能力提高,力学性能、加工性能较好。