Two-component simultaneous interpenetrating polymer networks.(SINs) from polyurethane(PU) and epoxy were studied. Two PU's (PPGUP,PTMGPU)were prepared by using poly (propylen glycol) (PPG) and poly (tetramethylene ether) glycol (PTMG) as the polyol.
The kinetics of PPGPU/epoxy SIN was studied by the differential scanning calorimetry, Epoxy curing reaction was slightly accelerated by the mixture of chain extending agent and crosslinking agent. PU reaction was retarded by the anhydride of the epoxy curing agent. Thus the reaction kinetics of SIN was complicated due to the interference of the reaction ingredients. The retardation effect of NMA on PU reaction was compensated by the catalytic effect of BDMA used as the catalyst of the epoxy resin. But the epoxy reaction was not influenced very much during the SIN formation.
From the dynamic mechanical analysis, it was found that PPGPU/epoxy SINs had a very good compatibility over the whole composition range. PTMGPU/epoxy SIN had slightly poor compatibility. The tensile strength of PTMGPU/epoxy SIN showed maximum at 20% PU. The impact strength of all SINs was enhanced as the PU content was increased. The PTMGPU/epoxy SIN had higher impact strength compared to PPGPU/epoxy SIN.