Dear members, I have a Benzyl methacrylate (monomer) and two types of crosslinkers , di(ethylene glycol) dimethacrylate (DEGDMA),
poly(ethylene glycol) dimethacrylate (PEGDMA) and Carbonyl iron powder(CIP). When I mix CIP with DEGDMA, its storage modulus and loss modulus increases but Tg( glass transition) decreases from the base matrix but while on mixing of CIP in the case of PEGDMA, Storage modulus, loss modulus, and Tg increase from the base matrix. Now I am worried, how to explain or what's are the reasons behind this scheme?
In both cases, you managed to improve mechanical properties with the addition of the Carbonyl iron powder, however, in the case of the combination DEGDMA + CIP the Tg decreases, which is probably caused by agglomeration of the powder and separation of phases. If the CIP powder does not fully blend with your polymer, the unreacted parts can move/flow more easily and this would decrease the Tg. You could argue that the addition of CIP to DEGDMA decreases the crosslinking density and consequently the Tg.
Dear Suliga, Thank you for response and I got your answer. But the problem is, Tg is decreasing and Strength increasing, which seems not a good relation? Can you please explain is it possible in any case Or it can be included in research with any supporting explanation as I didn't see any case like this? I will appreciate your response.
Hi, Can you clarify how much the Tg decreases? Is it a very significant change or several degrees?
I think that you can absolutely include that result in your research. Polymers are complicated and any kind of modification will influence their properties. Sometimes you add something to improve one property but you have tho sacrifice something else. I can give you a reference from my field, where nanoparticles where used with epoxy resin blends and the similar thing to what you've observed happened, storage modulus got improved and Tg decreased.
If the addition of CIP to DEGDMA is beneficial for some applications even though it decreases somehow Tg, it's still worth mentioning that and you shouldn't be so concerned about whether this is good/bad relationship. Also Tg is not one temperature, but usually quite a broad temperature range and again the decrease in Tg might only be a result of incomplete mixing. You might try to improve your mixing technique and measure the Tg again? I think as long as you are able to explain why your material behaves like this you're fine :)
Dear Suliga, It's not significant and slightly increase in one case and decrease in another case. Can you please give me the reference?
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