Higher aliphatic aldehyde polymers, VII: poly(n-decaldehyde)

摘要

n-Decaldehyde (DA) was polymerized to crystalline poly(n-decaldehyde) (PDA) of reasonable molecular weight in methylcyclohexane (MCH) solvent with lithiumtert-butoxide (LTB) as the initiator under carefully controlled temperature conditions. The polyacetal structure ofPDAwas established by IR and PMR spectroscopy as well as by the characteristic degradation of the polymer in the presence of 2,4-dinitrophenylhydrazine.PDAhad the dual melting behavior typical of aliphatic polyaldehydes with four or more side chain carbon atoms. The DSC scans of crystallinePDAin the first, or side chain, transition region showed as many as three endothermic peaks between 45 and 65°C. The X-ray diffraction pattern of crystalline PDA was similar to that which had been observed for other polyaldehydes but with a larger unit cell.PDAwas extruded at 53°C in a capillary rheometer and gave a filament whose X-ray diffraction pattern indicated medium orientation effect