Presentation on theme: "C.M. Roland Naval Research Laboratory Gary S. Buckley Cameron University."— Presentation transcript:
C.M. Roland Naval Research Laboratory Gary S. Buckley Cameron University
Outline A little terminology Work with hydrogels Can this shift to rubber materials? Materials used in rubber work Results Conclusions
A Little Terminology Crosslink – a covalent bond between two separate polymer molecules
Work with Hydrogel Materials Jing Ping Gong and Yoshinori Katsuyama, Advanced Materials, 15(14), Single Network Double Network (0.4 MPa) (17.2 MPa)
Key factors: 1. The two networks were homogeneous. 2. The difference in crosslink densities was maximized.
Can this idea translate to rubber materials? Two selected rubber materials: EPDM – contains double bonds and can be crosslinked with sulfur EPM – contains no double bonds and cannot be crosslinked with sulfur The idea: Blend EPDM and EPM followed by crosslinking with sulfur to see if mechanical properties are improved
Tensile Strengths Is the EPM chemically a part of the network?
Did EPM become a bonded part of the network? All EPM should be soluble if not a chemical part of network Soxhlet extraction to determine gel fraction
Gel fractions Indicates that EPM was not a chemical part of the network
Tensile Strength and Network Density Is there a homogeneity issue?
Are EPDM and EPM homogeneous initially? C-C bond length: ~ 0.15 nm
Potential Applications – Ballistics Bad response Good response
Conclusions Blended EPDM and EPM crosslinked with sulfur provides better tensile strength than crosslinked EPDM Blended EPDM/EPM tensile strengths continue to increase even as the network density levels off The increase in tensile strength of the blended material is modest – not on the order of the hydrogel work The EPDM/EPM system is not particularly homogeneous - work remains to be done to see if its homogeneity increases as the cure package increases