This can be caused by the more hydrophobic character of BDMA [22-26].
0025 -- Polymer IA (mol) EGDMA (mol) BDMA (mol) ME -- 0.
We selected DGEBA: TDI 1:1 (mol/mol) formulations with 1 phr of BDMA as the neat sample to be investigated by DSC, which is a compromise between these three different processes, leading to thermosets with 22% oxazolidone, 39% isocyanurate, and 39% of polyether in the network structure (27).
Figure 4 shows the plot obtained by TMA overlapped with the calorimetric curve obtained by DSC for the formulation DGE-BA: TDI:15% H30epo catalyzed by 1 phr of BDMA.
Final compositions for DGEBA: TDI 1:1 formulations with different proportions of H3Ovin and H3Oepo cured dynamically in the DSC with 1 phr of BDMA.
1] for the thermosets obtained from formulations DGEBA: TDI 1:1 with different proportions of H30vin and H30epo catalyzed by 1 phr of BDMA.
BDMA was not able to initiate the polymerization at the two selected concentrations.
One significant characteristic of an epoxy homopolymerization initiated by DMAP is the intense brown color that is developed from the beginning of the polymerization (the initiation with BDMA does not lead to colored products).
The average size of polyether chains produced using either BDMA or DMAP may be compared following the distribution of reaction products by SEC.
When adding BDMA
and heating beyond the cloud-point curve to obtain a homogeneous solution, there was a competition between the dissolution of PS and the advance in the polymerization reaction.