I am using 4,4’-Diaminodiphenylmethane (MDA) to cure Bisphenol A diglycidyl ether (DGEBA) based epoxy resin. Please tell me how to calculate the amount of MDA required to cure 5 g of DGEBA epoxy resin and How to conversion into phr?
The AHEW of MDA is about 49.5. I don't have the foggiest idea which DGEBA based resin you plan on using, but let's assume an EEW of about 200 as supplied. 5 g of resin thus equals 5/200 = 0.025 eq epoxy. Assuming you want 1:1 stoichiometry (again, who knows?), then 0.025 * 49.5 = 1.24 g of MDA per 5 g of resin.
To calculate phr, first convert the resin amount to 100 g. (5*20=100 g) Now, multiply the amine weight by 20 (20*1.24 = 24.8). So, the phr is about 25.
If you want to double check your phr calculation:
1. We know the phr of MDA is 25.
2. phr/100*(weight resin) = weight curative
3. 25/100*5 = 1.25
That checks out with the amount of MDA we calculated earlier to be used per 5 g per resin.
I hope this helps.
MDA stoichiometric mixing ratio with DGEBA epoxy resin is in the range of 27 to 30 pph. So, it is necessary to add 1.35-1.5 (gr) to 5(g) DGEBA resin.I have attached a reference in which in page 98, the ration of hardener and resin has been explained.
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