Stress‐optical behavior of poly(cis/trans‐1, 4‐cyclohexane dimethanol‐alt‐formaldehyde) (PCDO) networks

Abstract

SynopsisTwo samples of poly(cis/tmm-l,4cyclohexane dimethanol-alt-formaldehyde), having fractions of tmns configuration of cyclohexylene rings F, = 0.1 and 0.7, were synthesized by polycondensation of the appropriate mixtures of glycols with paraformaldehyde. These two samples were crosslinked by a chemical reaction using 2,4-bis@-isocyanatebenzyl) phenylisocyanate as the crosslinking agent. The stress-optical behavior of the resulting networks was studied a t several temperatures in the range 1 W C . The values of the optical configuration parameter Aa were 9.9 and 7.2 in units of cm3 for F, = 0.7 and 0.1, respectively. The temperature coefficient of this quantity was roughly zero. Theoretical analysis, performed using the rotational isomeric state model, proved that the only parameters that have an appreciable effect on the calculated values of Aa are those concerning the cyclohexane ring (i.e., F, and the optical parameter rm = A% -2A%H). Conformational energies, geometrical parameters, and contributions to the optical anisotropies from the oxymethylene oxide have no noticeable effect on the value of ha calculated for the polymer. In fact, values of ha calculated for the polymer at F, = 0 and 1 are very close to those obtained, respectively, for cis and tmns cyclohexane dimethylene. The theoretical values of Aa are roughly one order of magnitude lower than the experimental results; however, the theory reproduces satisfactorily both the variation of Aa with F, and its temperature coefficient.

Configurational properties of polyesters with cyclohexane rings incorporated in the main chain

“…4 The polymer obtained from the trans isomer (PTCDM) is crystalline and melts4,5 at 86 °C whereas that obtained from the cis isomer (PCCDM) is amorphous at room temperature. 6 Both polymers, however, have similar polarity. Actually the high preference for g±g± conformations of the oxymethylene sequences, in which the dipole moments of pairs of COC bonds are nearly antiparallel, is responsible for the relatively low polarity exhibited by both polymers.5 It would be important to extend these studies to aliphatic polyesters resulting from the condensation of aliphatic acids and 1,4-cyclohexanedimethanol.…”