Toughening of impenetrable interfaces by tethered polymer chains: Evaluation of the isolated interface at low and high strain -rates and of the distributed interface at high strain-rates

The development of a new, high strain-rate single fiber fragmentation test is described herein. This test was modeled on the widely-used, low strain-rate single fiber fragmentation test. Differences in interface quality that were observed at low strain-rate in three different materials systems were also observed at high strain-rate. The new test thus provides an evaluation of the isolated interface at high strain-rates.;The effect of polymer chains tethered to the interface on composite performance was investigated for both the isolated interface and the distributed interface. The tethered chain concept was tested on the isolated interface with the low strain-rate single fiber fragmentation test and the new high strain-rate single fiber fragmentation test. Improvements in interface quality due to polymer chains tethered to the interface were observed at low strain-rates as well as high strain-rates. The tethered chain concept was tested on a distributed interface at high strain-rates with a special compression test apparatus located at the Army Research Laboratory, Aberdeen, MD. Unlike what was observed in the isolated interface tests, there were no observed differences in composite performance due to tethered polymer chains in the distributed interface.