SynopsisThe melting and crystallization behavior of poly(tetramethy1ene terephthalate) and its copolymers with tetramethylene sebacate (> 20 mol%) has been studied using differential scanning calorimetry (DSC). The effect of the sebacate concentration on equilibrium melting temperature and crystallization behavior is discussed in terms of the theory of equilibrium crystallization of random copolymers. The multiple-melting behavior of these systems is described and interpreted in terms of the theory of equilibrium melting of chain-folded crystals, together with molecular fractionation during crystallization and melting and recrystallization during the DSC scan.

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SynopsisA range of hydroxy-terminated polymyrcenes has been prepared using hydrogen peroxide initiated polymerization of pyrolysate grade, P-myrcene in n-butanol solution at 100°C. An oligomeric fraction, containing a large proportion of dimeric material formed via the DielsAlder reaction, always accompapies the major polymeric fraction. Procedures are described for the removal of this oligo_meric material. Polyols so prepared and purified had number average molecular weights (M,) between 4000 and 2000 g m o l P at low and high initiator concentrations, respectively, with corresponding number average functionalities (f,) between 1.3 and 2.3 and polydispersities (MJB,,) of -1.3. The microstructure of the polyols was investigated using NMR spectroscopy from which the main mode of propagation during polymerization of myrcene was deduced to be 1,4 addition across the conjugated double bonds. Glass transition temperatures of the polymyrcenes measured by differential scanning calorimetry were in the range -50--60"C.

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