Physical gels formed by the nanostructuration of linear epoxy polymers based on amphiphilic monomers

I. A. ZUCCHI; C. E. HOPPE; M. J. GALANTE; R. J. J. WILLIAMS

Roma, Italia

Simposio; 4th International Symposium on Nanostructured and Functional Polymer-Based Materials and Nanocomposites; 2008

European Center for Nanostructured Polymers

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The reaction between stoichiometric amounts of diglycidylether of bisphenol A (DGEBA) and dodecylamine (DA) generates a linear polymer. The conversion of epoxy groups was followed by NIR spectroscopy at 100 ºC. A high conversion level (³0.95) was reached after 40 minutes. The obtained product (Tg= 10.4ºC) was completely soluble in different solvents such as: THF, acetone, DMF, toluene, dichloromethane and chloroform. However, after14 h heating at 100 ºC the polymer became insoluble in most solvents. Only a prolonged heating in p-xylene at 135 ºC could dissolve the polymer. A similar phenomenon was observed after a prolonged storage at room temperature. The explanation of the observed behavior is related to the self-assembly of dodecyl chains, a process that occurs much more slowly than the polymerization reaction. This leads to the formation of a physical gel where the crosslinks are formed by associations among dodecyl chains. In this way, the amphiphilic linear polymer generates a physical gel that could only be dissolved by destroying the association of hydrophobic chains using p-xylene at 135 ºC.