Synthesis of Two Novolac Type Epoxy Resin Curing Agents and their Application

Abstract

Two Novolac Resins Were Synthesized by the Reaction between Bisphenol A and Benzaldehyde (bis-BENR) or Bisphenol A and P-hydroxybenzaldehyde (bis-PHNR). Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) Were Applied to Characterize the Molecular Structure of Bis-BENR (or Bis-PHNR). then the Two Novolac Resins Were Used as Curing Agent for Bisphenol A Type Epoxy Resin (DGEBA). the Curing Reaction and Curing Kinetics Were Studied by Dynamic FTIR and Differential Scanning Calorimetry (DSC). Dynamic FTIR Showed that the Two Novolac Resins Reacted with Epoxy Resins and Formed a Crosslinking Network Structure. DSC Results Show that the Optimum Mass Ratio between DGEBA and Bis-BENR (or Bis-PHNR) Was 7:3, under which the Curing Reaction Processed Completely. the Mechanical Properties and Sulfide Resistance of DGEBA/bis-BENR (or Bis-PHNR) System Were Also Investigated. the Results Showed that when the Mass Ratio between DGEBA and Bis-BENR (or Bis-PHNR) Was 7:3, the Curing Coatings Had Optimum Mechanical Properties and Sulfide Resistance.

Thiourea modified low molecular polyamide as a novel room temperature curing agent for epoxy resin

“…It can be seen from the figure that the characteristic peak of epoxy group (at 915 cm −1 ) of the EP system corresponding to the synthetic curing agent completely disappeared after curing for 6 h, indicating that the curing degree was relatively complete. 18 …”

“…It can be seen from the gure that the characteristic peak of epoxy group (at 915 cm À1 ) of the EP system corresponding to the synthetic curing agent completely disappeared aer curing for 6 h, indicating that the curing degree was relatively complete. 18 It is worth noting that aer curing the E-51/TLMPA mixture, no characteristic peak was found at 2500-2600 cm À1 , the common spectrum segment of the -SH group. 19 The strength of -SH group itself is weak and difficult to detect also due to the interference of conjugated double bonds or triple bonds in the system.…”