ABSTRACT
Sealants should have good adhesion properties to different substrates and also provide the necessary physical properties to ll the gap between substrates. They serve as a barrier to exclude dust, dirt, moisture, chemicals, and air in end-use environments. Sealants can also serve to maintain a pressure differential between internal and external environments to attenuate mechanical shock and vibration. Since the applications of adhesives and sealants are different, the requirements for the mechanical strength of sealants are generally lower than those for adhesives. Therefore, sealant formulations usually contain large amounts of ller for cost reduction and gap-lling purposes.
