Viscoelastic Silicone Rubber Devices and Related Methods

Background
Traditional silicone rubbers are elastic polymers, or elastomers, which deform under the application of stress and regain their original shapes when the stress is removed. Silicone rubber’s rigidity is not impacted by its time under stress; that is, silicone rubbers deform by the same magnitude whether subject to sudden impacts or prolonged stresses.

Invention Description
Louis A. Bloomfield, Ph.D., at the University of Virginia has invented a broad class of viscoelastic silicone rubbers — including dense, foamed and comminuted materials — that respond differently under different types of stresses or impacts. These materials differ from traditional silicone rubbers in that some of their molecular bonds are permanent and others temporary, allowing the materials to exhibit unique properties.

These innovative new materials are solids, each possessing an equilibrium shape to which it returns in the absence of imposed stresses. Unlike traditional silicone rubbers, however, these new materials exhibit time-dependent stiffness: they are stiffer at short timescales as compared to long timescales. Accordingly, the viscoelastic silicone rubbers are relatively stiff and elastic when subjected to brief stresses, which causes them to resist changing shape. In contrast, when subjected to lingering stresses, these devices are relatively soft and accommodating and gradually do change shape.

Advantages
These novel viscoelastic silicone rubbers:

• Are highly resistant to compression
• Exhibit unique properties that allow them to be extremely resilient in response to sudden impacts and to deform extensively when subjected to prolonged stresses
• Can be manufactured in various forms, such as dense rubber, foam rubber or particles

Applications
The present invention has several possible applications, including all known applications of bouncing putty, viscoelastic urethane foams and other known viscoelastic, high-resilient compositions. Sample applications may include:

• Arch support, heal stabilizers or insoles for shoes
• Exercise devices and physical therapy materials
• Padding for bicycle seats, boots, earpieces, crutches, sports equipment, etc.
• Shock-dispersion devices and equipment
• Safety cushions and pads
• Toys
• Doorstops
• Furniture-leveling devices