Real time monitoring of temperature variation and optical transmission during gelation of acrylamide (AAm) at various crosslinker contents


Kara S., Pekcan O.

COMPOSITE INTERFACES, vol.11, no.1, pp.67-82, 2004 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 11 Issue: 1
  • Publication Date: 2004
  • Doi Number: 10.1163/156855404322681055
  • Title of Journal : COMPOSITE INTERFACES
  • Page Numbers: pp.67-82

Abstract

Free radical crosslinking copolymerization (FCC) of acrylamide (AAm) with various amounts of N,N'-methylenebis(acrylamide) (Bis) is performed at different onset temperatures (T,,,). Variation of temperature, T, and optical transmission, I-tr, are monitored in real time during the gelation process. The decrease in I-tr is modeled by the monomer consumption rate, and the gelation activation energies, DeltaE(G), are measured at each Bis content. During FCC, temperature increases to a certain level then decreases to its initial value as the gelation time increases, which is explained by the heat released during the polymerization process. Decrease in I-tr is attributed to the increase' in scattered light intensity, I-sc, during the formation of interconnected microgels in the system. It is observed that the number of microgels increases as the onset temperature, T-on, is increased. At a given temperature, high Bis content samples produce larger size of microgel particles compared to low Bis content samples.