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Unlikely. There are plenty of food grade foams for refrigeration, but I doubt you'll find one for high temperatures.
There are high temp applications for fireplace and chimney sealing but they tend to be bandaids and do you want to serve food out of a smoker sealed with chemicals?
There are products out there...but they are extremely expensive. Unless you have large piles of excess money to burn on your project, you are going to be far better off using rock wool, or other common nonflammable insulating product.