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Shin, Boo-Gyo,Cho, Tai-Yon,Yoon, Do-Y.,Liu, Binyuan The Polymer Society of Korea 2007 Macromolecular Research Vol.15 No.2
Poly(norbornene dimethyl dicarboxylate)s, (PNDMD)s, were prepared by addition polymerization with palladium(II) catalyst from pure exo-monomers, and their structure and properties were compared with those of poly(norbornene dicarboxylic acid dialkyl ester)s, (PNDADA)s. Both polymer series exhibited good solubility in general organic solvents and excellent thermal stability up to $330^{\circ}C$. Wide-angle X-ray scattering (WAXS) study indicated the presence of nano-scale layer-like order in amorphous PNDADAs, while PNDMDs showed random amorphous structure. The glass transition temperatures and dielectric constants of solid polymers were found to decrease as the alkyl side-chain length increases for both polymer series. However, PNDMDs showed lower glass transition temperatures and higher dielectric constants, as compared with those of PNDADAs containing the same alkyl substituents. This difference, caused by the higher side-group mobility of PNDMDs, may be closely related to the nano-scale order in amorphous PNDADAs and its absence in PNDMDs.
Liu, Binyuan,Li, Yang,Shin, Boo-Gyo,Yoon, Do Yeung,Kim, IL,Zhang, Li,Yan, Weidong Wiley Subscription Services, Inc., A Wiley Company 2007 Journal of polymer science Part A, Polymer chemist Vol.45 No.15
<P>Three novel functionalized polynorbornenes (PNB) with pendant dimethyl carboxylate group (carboxylates—acetate, propionate, and butyrate) are synthesized as a vinyl-type with a palladium (II) catalyst in high yield. The effects of size of substitutents, molar ratio of monomer to catalyst, solvent polarity, reaction time, and temperature on the polymerization of exo-norbornene dimethyl propionate were systematically investigated. The low molar ratio and temperature, as well as high polarity of solvent, and long reaction time, are favorable for the enhancement of the monomer conversion, especially, the solvent have an obvious effect on the catalyst activity. The resulting poly(cis-norbornene-exo-2,3-dimethyl carboxylates) (PNB-dimethyl carboxylates) show good solubility in common organic solvent and high thermal stability up to 360 °C. The glass transition temperature was detected by DMA at 331, 324, and 318 °C for acetate, propionate, and butyrate, respectively. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3391–3399, 2007</P> <B>Graphic Abstract</B> <P>Three novel functionalized PNB-2,3-dimethyl carboxylates (carboxylates—acetate, propionate, butyrate) are synthesized as a vinyl-type with a palladium (II) catalyst in high yield. The resulting PNB-dimethyl carboxylates show good solubility in common organic and high thermal stability up to 360 °C. The glass translation temperature was determined by DMA at 331, 324, and 318 °C for PNB-dimethyl acetate, PNB-dimethyl propionate, and PNB-dimethyl, respectively.</P><P> <img src='wiley_img/0887624X-2007-45-15-POLA22091-gra001.gif' alt='wiley_img/0887624X-2007-45-15-POLA22091-gra001'> </P>