Polymerization of Aromatic Aldehydes. III. The Cyclopolymerization of Phthaldehyde and the Structure of the Polymer

Determination of ceiling temperature and thermodynamic properties of low ceiling temperature polyaldehydes

“…Equilibrium between the PHA monomers and BF 3 ‐OEt 2 catalyst was reached within 15 min at each temperature. The temperatures were chosen based on previous reports of the ceiling temperature for poly(phthalaldehyde) (PPHA) . Figure shows the 1 H NMR spectra for PHA in the PHA polymerization between −25 °C and −35 °C.…”

“…In eq 3, [M] o is the initial concentration of monomer and T c is the ceiling temperature. For addition polymerizations, DH is exothermic on the order of tens to hundreds of kJ/mol, and DS is exo-entropic on the order of tens to hundreds of J/mol-K. 12,21 Equation 3 is used for reaction conditions where the initial monomer concentration is not 1 M.…”

“…Aso et al were successful in developing an in situ IR method for monitoring the monomer concentration for poly(phthalaldehyde) polymerization, but were limited by the temperature control. 12,13 The variable temperature NMR method for measuring monomer concentration and polymer thermodynamics has been disclosed before but has not been applied to very low ceiling temperatures polymers such as polyaldehydes. [14][15][16][17][18] In this paper, variable temperature 1 H NMR was used to measure the polymer ceiling temperature and to provide additional insight into the thermodynamics of polymerization for several low ceiling temperature polyaldehydes.…”

Acid‐catalyzed degradation mechanism of poly(phthalaldehyde): Unzipping reaction of chemical amplification resist

“…The polymer has ether oxygens in the central moital articles have been reported on the syntheses 7,8 ety of the polymer and carbonyl oxygens in the polyand the monomer decomposition, 9 only a few theomer end as shown in Figures 1(a) and 1(b), respectively. Supposed that the polymer composition is homogeneous, acid generation can be expected to…”

“…From NMR studies, poly(phthalaldehyde) is known to have trans (t) and cis (c) configurations, 16 where oxygen atoms in the main chain are on the opposite in the upper part of Figure 2(a), have six configurations: ttt, ttc, tct, ctc, cct, and ccc. Furthermore, they have many rotational isomers even when the mechanism, the central part of the polymer as well configuration is specified.…”