Assessing Rodent Gnawing of Elastomers Containing Soybean Oil Derivatives

Replacing petroleum-based components with biobased materials makes products more sustainable, but anecdotal evidence has suggested that this might also make them more attractive to rodents for gnawing. This study was conducted to determine if the inclusion of soybean oil or its derivatives in natural rubber, styrene–butadiene rubber, ethylene–propylene diene monomer, or flexible polyvinyl chloride (PVC) plaque samples affects the extent of gnawing damage by mice. The components tested were epoxidized soybean oil, degummed soybean oil, high oleic soybean oil, and styrenated soybean oil. Twelve treatments were tested, each exposed individually to 10 mice for 14 days. At days 8 and 15, the plaques were assessed for gnawing damage, both subjectively and by weight loss. Extensive gnawing was noted only on plaques made of PVC (both PVC standard and PVC with 10 PHR epoxidized soybean oil), and the gnawing damage difference between these two PVC treatments was not statistically significant. The other 10 treatments all showed negligible gnawing. The inclusion of soybean oil or its derivatives in common elastomers did not affect rodent gnawing.