The role of surfactant structure and monoethanolamine in the environmental stress cracking of polycarbonate

✍ Scribed by Douglas L. Faulkner

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 499 KB
• Volume: 32
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1986.070320513

✦ Synopsis

The critical strains required to initiate cracking of polycarbonate exposed to a number of poly(oxyethy1ene)ethoxylate surfactants were determined. Solubility parameters of the surfactants were calculated from knowledge of the molecular structure. A model proposed by Jacques and Wyzgoski that uses the square of the solubility parameter difference of the surfactant and polycarbonate and the surfactant molar volume was determined to be useful for predicting critical strains for polycarbonate. A major assumption in this model is that stress cracking is related to swelling or plasticization of the polymer by the cracking agent, which ultimately leads to the polymer's failure. However, the model does not predict the observed strong stress cracking of polycarbonate by monoethanolamine. In this investigation it was determined that polycarbonate is chemically degraded by monoethanolamine. This degradation is sufficient to initiate stress cracking at lower strains than would otherwise be predicted by solubility parameter and molar volume concepts. With the knowledge obtained from this investigation, it is possible to predict which poly(oxyethy1ene)ethoxylate surfactants are stress cracking agents for polycarbonate.