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STUDY ON polymerization mechanism OF 3, 9,-DIALLYL-3, 9, -DIBENZYL-1, 5, 7, 11-TETRAOXASPIRO [5, 5] UNDECANE

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Chinese Journal of Polymer Science 1992年第4期10卷 343-349页

作者：白如科胡悦邹应芳潘才元 Toshiyuki Uryu Department of Materials Science and Engineering University of Science and Technology of China Hefei China Institute of Industrial Science University of Tokyo

A new monomer, 3,9-diallyl-3, 9-dibenzyl-1, 5,7,11 - tetraoxa- spiro [5,5] undecane (6) was prepared by the reaction of 2- allyl- 2' - benzyl- propanediol - 1.3 with dibutyltin oxide, and then treated with CS_2. Monomer 4 could be initiated by cationic initiators to give a viscous polymer (white powder in the case of polymerization at 0℃). Upon the NMR and IR spectra of the obtained polymer, the components and their relative amount were estimated. The polymerization mechanism was discussed.

关键词： polymerization mechanism Cationic polymerization Spirocarbonates 3, 9-diallyl-3, 9-dibenzyl-1, 5, 7, 11-tetraoxaspiro (5,5) undecane

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Selective 3,4-polymerization mechanism of Isoprene Catalyzed by Rare Earth Alkyl Complexes

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Chemical Research in Chinese Universities 2014年第1期30卷 114-118页

作者： LIU Ying SUN Cuihong LI Xiaofang ZHANG Shaowen School of Chemistry Beijing Institute of Technology Beijing 100081 P. R. China College of Chemical Engineering Shijiazhuang University Shijiazhuang 050035 P. R. China

The mechanism of selective 3,4-polymerization reaction of isoprene catalyzed by the rare earth lutecium（Ⅲ） alkyl complexes [2,6-Me2Ph-N-CH2-C（CH2SiMe3）=N-PhMe2-2,6]Lu（CH2SiMe3）2（THF）was investigated by means of the M06/sdd method with solvation effects taken into account.The results show that the structure of the catalyst core remained almost unchanged as the isoprene molecules were alternatively inserted into the complex at two opposite sides.The Gibbs free energies of the coordination complexes,transition state and intermediates indicate that all the isoprene molecules prefer to insert into the complex with the 3,4-polymerization selectivity as catalyzed by the catalyst,which is consistent with the experimental observations.It is found that the insertion reaction of each isoprene is exothermic,which comes mainly from the coordination of the isoprene molecule to the lutecium（Ⅲ） atom.The solvation effects were confirmed important in predicting the Gibbs free energies of the present reaction system.

关键词： Isoprene polymerization mechanism Density functional theory study Rare earth catalyst

Thermal polymerization of Cyanate Ester-Benzoxazine:Study of a Functional Model Compound

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上海航天（中英文） 2022年第1期39卷 122-128,161页

作者： WANG Fan ZHOU Hui WAN Li DONG Bin LI Shengchao QI Huimin Key Laboratory of Specially Functional Polymeric Materials and Related Technology of Ministry of Education School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237China Shanghai Composites Science&Technology Co. Ltd.Shanghai 201112China

A novel benzoxazine(BOZ)monomer is synthesized by a pot method with solvent-free to blend with cyanate ester(CE).A soluble intermediate is obtained after being cured for 20 h at 80℃.The two model compound and the blends are analyzed with the infrared radiation(IR),nuclear magnetic resonance(NMR)spectroscopy,and differential scanning calorimetry(DSC).The results show that an intermediate of the iminocarbonate and BOZ structures is formed by the ring-open BOZ reacting with the cyanate groups and ring-unopened BOZ.Moreover,rearrangement and ring-opening occur in the postcure of the intermediate to form the alkyl isocyanurate structure with polybenzoxazine.

关键词： thermosetting resin benzoxazine(BOZ) cyanate ester(CE)resin polymerization mechanism

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Selective Insertion in Copolymerization of Ethylene and Styrene Catalyzed by Half-Titanocene System Bearing Ketimide Ligand： A Theoretical Study

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Chinese Journal of Chemistry 2017年第11期35卷 1731-1738页

作者： Xiaowei Xu Gaohong He Ning-Ning Wei Ce Hao Yu Pan State Key Laboratory of Fine Chemicals School of Petroleum and Chemical Engineering Dalian University of Technology Panjin Liaoning 124221 China School of Life Science and Medicine Dalian University of Technology Panjin Liaoning 124221 China

The copolymerization of ethylene and styrene can be efficiently carried out by using Cp＊TiCl2（N=CtBu2）/ MAO （Cp＊=η5-C5Me5） system, yielding the poly（ethylene-co-styrene）s with isolated styrene units. In order to in- vestigate the reasons for formation of the structure, the mechanism of copolymerization, especially the selective in- sertion of ethylene and styrene, is studied in detail by density functional theory （DFT） method. At the initiation stage, insertion of ethylene is kinetically more favorable than insertion of styrene, and insertion of styrene kinet- ically and thermodynamically prefers 2,1-insertion. That is different from the conventional half-titanocene system, in which the 1,2-insertion is favorable. At chain propagation stage, the computational results suggest that the con- tinuous insertion of styrene is hard to occur at room temperature due to the high free energy barriers （28.90 and 35.04 kcal/mol for 1,2-insertion, and 29.15 and 34.00 kcal/mol for 2,1-insertion） and thermodynamically unfavora- ble factors in two different conditions. That is mainly attributed to the steric hindrance between the coming styrene and chain-end styrene or ketimide ligand. The computational results are in good agreement with the experimental data.

关键词： polymerization mechanism density functional theory （DFT） half-tianocene copolymerization selec-tive insertion

13C-NMR STUDY ON THE CHAIN TERMINAL STRUCTURE OF POLY-1,3-PENTADIENE POLYMERIZED WITH RARE EARTH CATALYST

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Chinese Journal of Polymer Science 1987年第2期5卷 109-113页

作者：谢德民龚志王佛松 Changchun Institute of Applied Chemistry Academia Sinica Changchun Changchun Institute of Applied Chemistry Academia Sinica Changchun

The sequence distribution and the terminal structures of poly-1,3-pentadiene chains obtained by rare earth catalyst and effect of polymerization temperature on microstructure of the polymer have been investigated by;C-NMR method. According to experimental results it was supposed that terminal active growing chain of the polymer would be four types of anti- and syn-η;-allyl structures. When polymerization temperature was reduced, the content of cis-1,4-poly-1,3-pcntadiene increases. It can be explained by isomerization between anti- and syn-η;-allyl. The process forming trans-1,2 unit instead of 3,4-unit were also described.

关键词： Poly-1, 3-pentadiene Terminal structures Diene polymerization polymerization mechanism Sequence distribution.

Influences of SiO₂/Na₂O Molar Ratio on Aging and Chemical Modification of Water Glass

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Open Journal of Inorganic Chemistry 2016年第2期6卷 125-134页

作者： Huan Yang Hailan Xu J. Kriss Frank Guangtong Xu Weiwei Huan Chaoying Ni Yuxiang Yang School of Chemistry and Molecular Engineering East China University of Science and Technology Shanghai 200237 China Department of Materials Science and Engineering University of Delaware Newark DE 19716 USA State Key Laboratory of Catalytic Materials and Reaction Engineering (RIPP SINOPEC) Beijing 100083 China Key Laboratory of Chemical Utilization of Forestry Biomass of Zhejiang Province Zhejiang Agricultural & Forestry University Lin’an 311300 China

In this paper, the content of water glass before and after adding modifying agent was measured by Trimethylsilyl-gas-chromatography. The experimental results showed that different modulus of water glass could generate different content of mono-silicate acid and oligomeric silicate acid in water glass. After a period of storage, different modulus of water glass led to decrease of silicate content at different levels. Because higher content of Na2O in water glass tended to incur the alkaline polymerization, the occurrence of depolymerization of silicate species would lead to an increase of oligomeric silicate species, resulting in a drawback of silicate species content after a period of storage. And contrary to that, lower content of Na2O in water glass tended to incur the acidic polymerization. When the modifying agent was added to the newly made water glass, the amount of mono-silicate acid and oligomeric silicate acid also decreased. In modified water glass, the change of each silicate acid species was less than that in unmodified water glass. These results showed that the modifying agent retarded the aging of water glass. It had remarkable significance on the theory and practical application of water glass chemistry.

关键词： Water Glass Modulus polymerization mechanism Chemical Modification TMS-GC Method

聚合物聚合机理的MALDI-TOF MS研究

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聚合物聚合机理的MALDI-TOF MS研究