Synthesis of spiro polymers,

Synthesis of the first totally organic spiro polymer was accomplished by the reaction of 1,4-cyclohexanedione and pentaerythritol in benzene plus a trace of p-toluenesulfonic acid to produce the polyspiroketal. The polymer did not melt, but began to decompose at 350°C. Although it was insoluble in most common solvents, it was found to be soluble in hexafluoroisopropanol. The x-ray diffraction indicated the polymer was very highly crystalline. A series of lower molecular weight related polymers were prepared by carrying out a similar condensation with a mixture of 1,4-cyclohexanedione containing 5–50 mole-% of cyclohexanone. In order to prepare a material with greater solubility, a polyspiroketal was prepared from 1,10-cyclooctadecanedione plus pentaerythritol. This polymer was soluble not only in hexafluoroisopropanol, but to a limited extent in dimethyl sulfoxide.