Originally Published MPMN March 2009

BREAKTHROUGHS

Cornstarch Migrates to Medical Applications

Bob Michaels

Cooks and bakers know that cornstarch is used in everything from gravies and sauces to cakes and pies. But cornstarch is also serving as the base for superabsorbent polymers for managing water and other fluids in a range of medical applications.

Used in bandages and wound dressings, starch-based Reon polymers from Absorbent Technologies Inc. offer several advantages over petroleum-based or synthetic superabsorbent polymers, including fluid management capabilities, sustainability, and biodegradability. “Most synthetics are capable of absorbing fluids,” notes Reon product manager David Westlund, “but the manner in which they bind the fluid makes it very difficult to recapture or manage that fluid.”
Reon can both retain and release moisture. A low-swell material that can hold 500 times its weight in water, it has a cross-linked network of flexible, insoluble polymer chains. Through diffusion and molecular attractions, these chains can hold large amounts of moisture and expel it when external pressure or force is applied. “That’s something [Reon] can do over and over again during its useful life,” states Westlund. “This characteristic sets it apart from many synthetics.”
Since its fluid management properties maintain a proper balance between moisture and dryness, the polymer is effective in bandages and wound dressings, helping to accelerate the healing process and reduce scarring, Westlund says. Reon can also be used in surgical sorbents, absorptive powders, absorbent pads, and hot and cold therapy packs.
Although virtually any starch can be employed in starch-based polymers, Reon consists of ungelatinized cornstarch because of its availability, price, and the consistency and quality of the products it creates, according to Westlund. The material ranges in size from 8-mesh (approximately 2400-µm) granules down to 200-mesh (approximately 74-µm) powders. For medical applications, smaller granules or powders are preferred. Because medical products often come in contact with the skin, sodium rather than potassium formulations are used.
Westlund touts Reon’s “green” features. “In its unhydrated granular or powder form, it is extremely stable and will last for many years,” he states. “Once hydrated, the degradation process depends greatly on the amount of microbial activity present. In most disposal situations, you will probably be looking at about six to nine months for the product to completely biodegrade.” The material, he adds, can be safely deposited in compost heaps or the soil as long as it has not absorbed hazardous substances. In addition, Reon is made using a distillation column that can recycle upwards of 99.5% of the materials used during the drying process. Virtually the only by-product is ammonia gas, which can be recaptured and transformed into ammonium phosphate for use as cropfertilizer.
Absorbent Technologies Inc., Beaverton, OR
www.reon.com
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