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Sealants

A sealant’s primary function is to seal or to provide a barrier between one structure (surface) and either an environment or another structure (surface). The way in which this is achieved can be quite varied and is highly dependent upon the form and chemistry of the material. In turn this has an impact upon the way in which the sealant is used and applied. Aspects such as viscosity, flowability, cured hardness, gap filling capability, cohesive strength, barrier properties, electrical properties, thermal properties, degassing ability will all have an impact upon the type of material used. Sealants are often quite difficult to handle and apply, and require efficient curing. These issues, in addition to cost factors, need to be considered.

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The main industry challenges focus around being able to handle and dispense the sealant effectively and to subsequently cure rapidly at a time of choosing. Cost is another challenge in that unlike adhesives, sealants are most often used in much larger quantities and volumes. There is a perception that sealants are inferior to adhesives due to their often lower hardness and internal strength but this must be assessed against the very different property of being able to seal and act as a barrier rather than taking load.

TWI is unique in bringing together expertise, understanding of the adhesion process, analytical equipment, diffusion characteristics testing and measurement of other distinct properties such as thermal conductivity.

A recent project has seen TWI working with an aerospace client on identifying cure-on-demand sealants and also the ability to automate dispensing of other paste systems where stringing, access, cost and time are issues. TWI developed a number of attractive options to consider in more detail.

For more information, please contact us.