Hi I was wondering where I should look and what specifically should I study if i am trying to understand foam extrusion as a chemical process. , why certain defects appear in foam products considering that they are as a result of some extrusion or chemical mistakes. in short, i want to know enough to be able to a control how EPS foam behaves/shapes (to obtain certain properties in desired coefficients/amounts if possible). I would like to know as well how much studying (time) would this take, if anyone knows, and the level of difficulty of the task. Thanks.