CONSTRUCTION AND SIMULATION A Moving Boundary approach of Capturing diffusants Penetration into Rubber: FEM Approximation and Comparison with laboratory Measurements

To model the penetration of diffusants into dense and foamed rubbers a moving-boundary scenario is proposed. After a brief discussion of scaling arguments, we present a finite element approximation of the moving boundary problem. To overcome numerical difficulties due to the a priori unknown motion of the diffusants penetration front, we transform the governing model equations from the physical domain with moving unknown boundary to a fixed fictitious domain. 

Rubber is one of most usable polymers in our daily life, where it is employed for multiple purposes ranging from tires to materials for daily use, medical devices, and toys. The source of the natural rub ber is the latex of rubber trees (esp. he vea brasiliensis). Due to its softness, the use of natural rubber is limited. Besides natural rubber, synthetic rubbers are widely used. They are usually produced from petroleum byproducts. To develop the wanted toughness and strength, crosslinking of the rubber molecules, e.g. by vulcanization, is required. There are several ways to crosslink rubber, but the most common way is to add sulfur components that help forming bonds between rubber molecules.