Moisture adsorbing polymers protect against humidity and moisture

Brownell Ltd has developed a range of moisture adsorbing polymer products, which can be used in a wide range of systems, instruments and applications. Polymer adsorbents are intended to be used were conventional desiccants are impractical and an alternative moisture control system is required.

Versatile Moisture Adsorbing Polymer (VMAP) is a molecular sieve based moisture adsorbing polymer. This product is extremely efficient at extracting water vapour from the atmosphere. These products are for applications, where virtually dry atmospheres are essential. They will help prevent against electrical short-circuiting, insulation breakdown, visibility loss and construction materials instability.

The structure and nature of the VMAP product range allows for the material to be fixed in place, using screw fasteners, adhesives or other mechanical retention methods.

Molecular sieves based materials have a very high polar preference towards water vapour this strong bond means that the molecular sieve will not readily give up its retained moisture. Therefore the VMAP products cannot be re-activated and have to be replaced once saturated.

Moisture Adsorbing Board (MAB) is a silica gel based product available in sheet-form both 0.8mm & 1.6mm thick. The moisture adsorption characteristics are different to those of the molecular sieve products, silica gel does not have the same affinity for moisture vapour. This means that the material can be reactivated by oven-drying in a ventilated oven and cooling in a container sealed to prevent the crystals adsorbing moisture. This product is produced on a roll 200mm wide and can be cut to length to suit. The board product can be punched or cut to suit custom requirements. Owing to the thermoplastic nature of the polymer, this product can be thermo formed. It is a practical alternative to conventional bags for applications where space is limited. The narrow thickness of the board allows it to access apertures, which would be inaccessible to desiccant bags. MAB can be cut to any size for easy installation and fixing and is available in customer’s specific requirements.

The fact that the desiccant material is combined with a polymer ensures that these products have a very low tendency to dust even under extreme shock & vibration. This makes these products very suitable for high stress applications were conventional desiccants have a history of failure. This will all but eliminate the potential of having loose desiccant in equipment.