I have been doing some experiments with isophthalic resins, measuring their ability to damp sound. The resin is filled with bentonite clay particles. All was going well until the guy who is making the samples used a resin from a different supplier. It gave readings half the value of the previous samples. Changing back to a new batch of original resin restored the values, measured originally.
Both resins were described as isophthalic. I know what this refers to. Does anyone know if isophthalic resins are made with different ingredients, whether the acid or anhydiride are used, whether styrene is always used, and which polyols are used?
thanks.
Cat