Hello everyone,
I'm trying to synthesize polyurethane from sunflower oil and aliphatic di-isocyanate IPDI (isophorone diisocyanate) with a brittle and rigid film form.
First of all, I convert sunflower oil into polyol with glycerol at 230 Celcius degree. After synthesizing the partial glycerides from sunflower oil, I add IPDI with the presence of a stannous octoate catalyst at 50 Celcius degrees. The reaction carried 40 mins at 50 Celcius and then heated to 95 Celcius and continued until the isocyanate will disappear in FTIR (it takes approximately 2 hours) I use equivalent moles of NCO for OH groups (NCO:OH ratio is 1:1 in the polyurethane.) After the reaction was completed, I put the polyurethane into a petri dish and hold 24 hours in a oven at 50-60 degrees.
My polyurethane doesn't dry even if I hold it 48 hours instead of 24 hours in the oven. It is still sticky and can't absorb the drug. Since I am studying drug delivery, I avoid using any drying agents like metal naphthenates.
Is there any chance to get rid of this drying problem? How? Can I fix the problem by using any crosslinking agent or chain extender while producing polyurethane? I was not using them. I am also not using a solvent in the synthesis.
I will be very happy if you share any info about this issue.
Thank you,
Sedef
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