Submitted to: Journal of Applied Polymer Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/7/2005
Publication Date: 12/19/2005
Citation: Song, B., Chen, W., Liu, Z., Erhan, S.Z. 2006. Compressive properties of soybean oil-based polymers at quasi-static and dynamic strain rates. Journal of Applied Polymer Science. 99:2759-2770. Interpretive Summary: Polymeric materials prepared from readily available, renewable and inexpensive natural resources, such as starch, protein and vegetable oils, have become increasingly important. Polymeric materials from soybean oil have shown a variety of mechanical properties, ranging from elastomer through ductile to rigid plastics. In this work, three soft soybean oil-based polymeric materials have been developed. Their mechanical properties have yet to be determined; for example, how soft specimens deformed at constant strain rates under equilibrated stresses. A novel modified split Hopkinson bar (SHPB) method was used for testing of these soft materials. Also, a simple model was provided to describe the experimental results.
Technical Abstract: Three soft polymeric materials have recently been developed through the reaction of epoxidized soybean oil with diamine compounds. The quasi-static and dynamic mechanical behaviors of these three polymeric materials at various strain rates have been determined. High-rate experiments were conducted with a split Hopkinson pressure bar (SHPB) modified for low-impedance material testing. Precisely controlled loading pulses in the SHPB experiments ensured that these soft specimens deformed at nearly constant strain rates under dynamically equilibrated stress during dynamic compression. The compressive behaviors for all three materials were found to be strain-rate sensitive with different rate sensitivities. All three materials were found to be capable of deforming to very large strains with significantly non-linear stress-strain behaviors. Through the combination of a strain-energy function and a viscoelastic description for solid polymers, a compressive constitutive model with strain-rate effect has been developed to accurately describe the experimental results for all three materials under both quasi-static and dynamic loading conditions.