Radical ring-opening polyaddition of a bifunctional vinylcyclopropane bearing a spiroacetal moiety with dithiols
✍ Scribed by Tadashi Okazaki; Fumio Sanda; Takeshi Endo
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 165 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0887-624X
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✦ Synopsis
Radical polyadditions of vinylcyclopropane having spiroacetal moiety, 1, 10divinyl-4,8,12,15-tetraoxatrispiro[2.2.2.2.2.2]pentadecane ( 1), and various dithiols were examined. 1 was prepared by the reaction of 1,1-dichloro-2-vinylcyclopropane and pentaerythritol, and radical polyadditions of 1 and dithiols were carried out at 60 and 120ЊC for 20 h in the presence of an appropriate initiator (3 mol % vs. 1) in degassed sealed ampoules or at 20ЊC under photo irradiation by using a 400 W high-pressure mercury lamp. Poly( 1), pale yellow transparent viscous polymers was isolated by reprecipitation with ether containing a small amount of triethylamine to avoid hydrolysis of the polymer. The obtained polymers were soluble in chlorobenzene, DMF, and chloroform but insoluble in ether and n-hexane. The molecular weights of the polymers obtained from aliphatic dithiols were smaller than those from aromatic ones. The structure of the polymer was determined by comparing the NMR spectra with those of the model compounds, which were obtained by radical addition of 1 and benzyl mercaptan. The reaction proceeded through radical polyaddition of dithiol to 1 via radical ringopening polymerization of the cyclopropane ring.