Characterization of Extent of Cure of Form-in-Place Compounds

Form-In-Place (FIP) gasketing is particularly well suited to provide effective EMI shielding for wireless handsets, PDAs, PC cards, telecom base stations, and many other compartmentalized electronic assemblies. This method of gasketing provides effective cost savings in the form of raw materials, labor and assembly time. The elastomeric compounds can be engineered to have advanced electrical and/or thermal performance in addition to environmental sealing. The performance of FIP gaskets is highly dependent on the cure rate and cure state of the silicone-based matrix. However, it is sometimes difficult to use traditional methods to characterize the extent of cure of such compounds due to application differences and cure chemistry. In this study, we present a simple and practical method to characterize the extent of cure of FIP compounds. The effect of temperature, humidity and time on the extent of cure has been extensively studied with this method using high performance electrically conductive FIP electrical conductive elastomer gaskets as an example.