A Kenaf Fiber Based End-Grain Sandwich Core Material for Composites

Period of Performance: 01/01/2002 - 12/31/2002


Phase 1 SBIR

Recipient Firm

Polymer Bridge Systems, Inc.
1001 Chalkstone Drive
Mitchell, SD 57301
Principal Investigator
Firm POC


The high cost of core material in the composites industry remains a significant barrier to expansion. Composite projects, designed to replace metal, concrete, or wood, especially large projects such as bridge decks, regularly fail when it comes to cost analysis. The composites industry, for fifty years, has relied upon end-grain balsa wood core, due to its strength and low weight, as the material of choice. Balsa average 9 lbs/cubic foot density whereas other woods are 30 lbs. cu. ft. and up, the kenaf inner fiber is seven to eight lbs/cubic foot and a fraction of the price of balsa. A Kenaf-based core provides "balsa-like" inner fibers, and when the sticks are pressed and borded they become a very strong "end-grained" block. The resulting core appears to be stronger than balsa in compression and "core-shear" due to the smaller diameter sticks. Core shear is the all-important test when one evaluates the dynamic behavior of a composite sandwich cored structure, and load-carrying ability in compression determines the overall strength of the sandwich-cored part. The proposed project shall demonstrate the feasibility of this material as a composite sandwich core.