TY - JOUR
AU - Rudin, Alfred
AB - The degree of cure of various resole phenolic resins was assessed from their resistance to acetone extraction. Cured woodflour composites of resoles were also characterized by dynamic mechanical tests in linear viscoelastic behaviour regions. Acetone extraction is not a sensitive discriminator between highly cross‐linked resins. In addition, residual basic catalyst promotes aldol condensation reactions of acetone to produce materials that are absorbed in the phenolic resin so as to provide negative weight loss data on extraction. Despite its inaccuracies, however, this solvent resistance test is still useful as a go/no‐go specification technique. Dynamic mechanical tests were performed on molded resole/woodflour composites. This is a useful method for characterizing degree of cure and residual reactivity of the phenolic resin. Degree of cure increases with curing time, temperature and resin pH, with pH being the most important variable. Resins cured at pH's near neutral are linked by ether linkages rather than the more stable methylene bridges. The final degree of cure of woodflour composites depends heavily on the curing conditions (pH, time, temperature). It does not appear to be crucial how the initial resoles were made (i.e., catalyst, phenol/formaldehyde mole ratio or duration of the condensation reaction time) so long as the resoles have relatively high molecular weight. Curing should preferably be at temperatures below 180°C to minimize degradation of the polymer.
TI - Effects of resin and curing parameters on the degree of cure of resole phenolic resins and woodflour composites
JF - Journal of Applied Polymer Science
DO - 10.1002/app.1990.070401126
DA - 1990-12-05
UR - https://www.deepdyve.com/lp/wiley/effects-of-resin-and-curing-parameters-on-the-degree-of-cure-of-resole-bCjaHaXkb8
SP - 2135
EP - 2149
VL - 40
IS - 11‐12
DP - DeepDyve
ER -