Unusual cationic ring‐opening behavior of a novel six‐membered ring spiro‐orthocarbonate bearing adamantane backbones

In search of a composite with low stress and low shrinkage properties, this study includes matrix‐assisted laser desorption/ionization time‐of‐flight analysis of the photoinitiated cationic polymerization between an expanding monomer [1,5,7,11‐tetraoxaspiro[5.5]undecane (TOSU)] and a diepoxide [bisphenol A diglycidyl ether (BADGE)]. Past studies using NMR and differential scanning calorimetry analyses concluded copolymerization indirectly on the basis of deviations from homopolymer product data. This is the first study to provide direct evidence of copolymerization between these species. Unlike previous research, this study enables the identification of the TOSU homopolymer and the absence of the BADGE homopolymer, suggesting initial cationic activation of TOSU. In addition to peaks that correspond to the presumed mechanism for six‐membered TOSU polymerization, many peaks have a net gain or loss of cyclic carbonate in support of a new polymerization mechanism participating in the reaction. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5962–5970, 2005

Section: Resultsmentioning

confidence: 99%

Matrix‐assisted laser desorption/ionization time‐of‐flight analysis of the copolymerization reaction of an expanding monomer with a diepoxide

Miller

Holder

Guthrie

et al. 2005

Unusual cationic copolymerization behavior of a six‐membered ring spiro‐orthocarbonate bearing adamantane backbones with a monofunctional epoxide

Hino

Ito

Endō

2005

Copolymerizations of a six‐membered ring spiro‐orthocarbonate bearing adamantane backbones (AD‐SOC, 1) and a monofunctional epoxide, PGE, in the presence of cationic initiators such as Sc(OTf)3 were carried out under various reaction conditions. As a result, instead of the anticipated poly(ether‐ether‐carbonate) 11, two types of copolyethers (12 and 18) consisting of two or three types of ether components having different substituent groups were unusually formed along with the evolution of carbon dioxide gas, in which AD‐SOC efficiently acted as the corresponding oxetane equivalent monomers 3 and 4. Furthermore, the copolymerization behavior, including the formation of copolyethers 12 and 18, unexpectedly and significantly depended on the reaction conditions, such as the concentration of the initiator. For example, the copolymerizations with 5 mol % of Sc(OTf)3 mainly afforded copolyether 18, while those with 1 mol % mainly gave copolyether 12. In addition, treatments with 5 mol % of Sc(OTf)3 also yielded CH2Cl2, THF, and DMF‐insoluble networked products, indicating relatively higher thermal stability compared with a common polyether. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1729–1740, 2005

Dimensionally and thermally stable polymer, containing disordered graphitic structure and adamantane

Burnham

Roth

Zhou

et al. 2006

In an attempt to develop a low‐k interlayer dielectric, adamantane‐diphenyldiethynyl moiety containing oligomer is prepared. Oligomerization of 1,3,5,7‐tetrakis[3/4‐ethynylphenyl]adamantane (4) is accomplished by a Glaser–Hay oxidative coupling with 1,3,5‐triethynylbenzene and phenylacetylene end‐capping agent. The CHCl3 soluble oligomer is then thermally treated by step‐curing at 200, 300, 380, and 450 °C for 30 min at each temperature under nitrogen flow to render a shiny void‐free black polymer. TGA analysis indicates that the polymer is stable under nitrogen up to 500 °C with a marginal decomposition up to 800 °C. Solid‐state 13C NMR, Raman scattering, and FTIR are used to characterize the structure of the polymer. The polymer consists of amorphous carbon networks with the adamantane moieties and nanosized graphitic regions (clusters), which are generated from the thermal crosslinking of the diphenyldiethynyl units. It shows a remarkably low linear coefficient of thermal expansion (∼25 ppm/°C), presumably due to the presence of the disordered graphitic structure. Its high density (∼1.21 g/cm3), refractive index (∼1.80 at 632 nm), and Young's modulus (∼17.0 GPa) are also consistent with the interpretation. This study reveals important details about the effect of microscopic structure on the macroscopic properties of the highly crosslinked polymer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6909–6925, 2006