NIST/industry collaboration yields new instrumentation for monitoring nanocomposites compounding. .

In collaboration with an instrument company, NIST scientists have developed on-line, real-time instrumentation for monitoring extrusion compounding of polymer/clay nanocomposites. The new instrument is a multi-functional device that addresses the need for instant characterization of the compounding process and the compounded product. The sensor device is a dielectric slit die that attaches to the end of a twin screw compounding extruder and measures the electrical, optical, rheological, and ultrasonics properties of the compounded product. The objective is to acquire a package of data from dif-ferent sensors in order to deduce information about the microstructure of the clay filler particles, and to determine if aggregate clay has dispersed and exfoliated into small nanosize particles within the polymer matrix. This information is important because it has been established that a few percent of clay mixed into the polymer can greatly enhance the mechanical and fire retardant performance of the composite if dis persion and exfoliation of the clay occurs.

The instrument project is part of a larger program to fully characterize polymer/clay nanocomposites using both on-line and off-line measurements. Off-line measurements, such as x-ray diffraction, NMR spectroscopy, and neutron scattering, are correlated with on-line data to give a detailed picture of the micro-and nanoscale structure of the nanocomposite.

CONTACT: Anthony Bur, (301) 975- 6748; [e-mail].