RADIATION INDUCED MODIFICATION OF ORDERED POLYMERS FOR COMPRESSIVE STRENGTH

SOLUTION PROCESSED ORDERED (LIQUID CRYSTAL) POLYMERS MAY BE MODIFIED BY EXPOSURE TO ELECTRON OR PROTON BEAM RADIATION TO PRODUCE MATERIALS WITH IMPROVED COMPRESSIVE STRENGTH, DIMENSIONAL STABILITY, HIGH SPECIFIC STIFFNESS, GOOD STRUCTURAL DAMPING, HIGH TEMPERATURE CAPABILITY, AND ENVIRONMENTAL RESISTANCE FOR USE IN AEROSPACE STRUCTURES. OUR APPROACH IS TO EXPLOIT THE INHERENT MECHANICAL AND THERMAL STABILITY OF A CLASS OF RIGID ROD ORDERED LIQUID CRYSTALLINE POLYMERS AND TO IMPROVE THEIR TRANSVERSE PROPERTIES VIA MODIFICATION BY EXPOSURE TO ELECTRON OR PROTON BEAM RADIATION. AS A RESULT, WE WILL ACHIEVE A HIGH COMPRESSIVE STRENGTH FOR FILMS AND FIBERS. THE PROPOSED PROGRAM WILL EVALUATE THE FEASIBILITY OF RADIATION INDUCED MODIFICATION OF ORDERED POLYMERS TO IMPROVE TRANSVERSE MECHANICAL PROPERTIES AND HIGH COMPRESSIVE STRENGTH, OVER 150 KSI WITH LESS THAN 20 PERCENT REDUCTION IN LONGITUDINAL PROPERTIES. POLYPHENYLENE BENZOBISTHIAZOLE (PBT) IS CURRENTLY THE MOST TECHNICALLY ADVANCED LYOTROPIC ROD-LIKE POLYMER, AND WILL BE USED IN THE PROPOSED PROGRAM.