Dear All,
I study depolymerization of siloxane polymer by Proton NMR. The manufacture value of degree of polymerization of pure siloxane polymer was reported as ~ 80. I did depolymerization of siloxane and the obtained depolymerizied fraction was analyzied by Proton NMR. Taking into account the obtained integration values of depolymerizied fraction in NMR spectrum, i calculated approximate polymerization degree of this fraction/ obtained polymer which appeared to be higher then polymerization degree of neat/unreacted polymer. Has anyone any ideas what it could be ? Thanks to all for your time!
Regards,
Iryna
hello, it's impossible to get higher degree of depolymerization than that of polymerization unless something wrong have happened.
did you measure degree of initial polymer by yourself or did you trusted in reports??
validate your method of measurement by repeating the test
good luck
There is a possibility that the depolymerization of the polysiloxane was not done in a proper way. An increase in the average degree of polymerization indicates, of course, that the polymerization path has been enhanced probably by inadequate heating.
Also, it would have been better if you checked the manufacturer's value of the average DP by some preliminary test.
Hi Seyed,
The problem is I have the manufacture value of polymerization degree and I comparing it with the depolymerizied siloxane. For depolynerizied siloxane I am using Proton NMR to estimate an avarege polymerization degree, but I can not use Proton for the determination of unreacted polydimethylsiloxane polymerization degree as it has end groups methyl ones which are barried in the backbone shift. So the manufacture value is very low as compared with the depolymerizied samples. Do you know other methods which i can use to determine Mn or polymerization degree for siloxane?
Iryna
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