Equipment Available Within the Department (click here to return to homepage)

The WAXS D8 Discover system from Bruker works in transmission or reflection with an area detector and copper anode. The advantage of an area detector is the ability to see reflections from samples having not much of a scattering curve; we found the improvement to be about a factor of 100 vs. the normal receiving slit collimation and point detector. The disadvantage is a loss in resolution for narrow peaks (a characteristic not that relevant for polymers). Seen in the picture is about 10 polymer films mounted for successive measurement; this equipment comes with an xyz table that allows for multiple measurements. Transmission data on this instrument is good down to 5 degrees.

The pinhole-collimation SAXS system from Rigaku with a copper anode is actually two systems in one, it has both a 2-D wire detector for SAXS measurements from q=0.07 nm-1 to 4 nm-1, as well as an image plate detector for wide-angle measurements from 5 to 45 degrees. The microfocus copper source gives you rotating anode intensities with the associated maintenance headaches. There is a full set of attachments, for liquids and a heating cell, as well as an autosampler. The system is designed to collect patterns from weakly scattering materials, e.g. polymer fibers.

The DMA used in our lab is from Rheometric Scientific (since acquired by TA Instruments) model RSA II. The RSA II tests a wide variety of solid materials, ranging from low-modulus materials such as foams, gels or thermoset resins, to high modulus polymer-matrix composites. We have a number of fixtures: parallel plate, shear sandwich, three-point bending, film-fiber, and monofilament fiber. The RSA II can do continuous frequency sweeps; perform temperature ramps and sweeps in four zones, with sweep rate and strain amplitude programmable in each zone; make stress relaxation measurements in tension, compression, and bending, as well as forced oscillation measurements. No other instrument can perform all these tasks as easily and as accurately.

This SR5000 stress-controlled rheometer from Rheometric Scientific is used to measure the steady-shear and complex viscosity of polymer melts. The shear-rate region for the former is much lower than the capillary viscometer, so we view this instrument and the capillary viscometer as complementary. These measurements can be done in a cone-and-plate or parallel plate configuration, and can be done at temperatures from room temperature to polymer degradation temperature. We also have the ability to make these measurements under nitrogen, to reduce the rate of polymer degradation.

The Instron Model 3210 Capillary Viscometer is used to measure the viscosity as a function of shear rate at high shear rates. (1-1000 s-1). One simply melts polymer in a barrel, pushes it out a very small hole at a given rate, and measures the force. However, the measurement requires three corrections: one for a non-Newtonian flow profile, one for the fact the small hole has finite length, and one for possible slip at the wall. We have a total of 10 capillaries, and these capillaries allow us to make all three corrections.

Differential Scanning Calorimeter

The Q1000 is TA Instruments top-of-the-line, research grade DSC. Our Q1000 includes Advanced Modulated® DSC, a 50-position autosampler, liquid nitrogen cooling for a wider temperature range and faster cooling rates. While designed primarily for the most demanding researcher, it is equally suitable for routine automated analyses. We use this equipment for many things: determining the kinetics of curing thermosets, determine the rate of crystallization, oxidative induction tests, as well as more routine tasks such as percent crystallinity and Tg determination. The extreme sensitivity of this instrument and excellent baseline stability makes this instrument ideal for measuring properties where only a small amount of material is available, or transitions are very weak.

This Digital Instruments SPM is used to measure the surface topology (i.e. the shape of the surface) by running a nanometer-size probe over the surface and measuring the deflection of the probe. Think of what happens if you run your finger over concrete vs. over a car, one is smooth the other rough. Your finger goes up and down on the concrete, but smoothly glides over the car. This is what an SPM does.

The Phi Electronics X-ray Photoelectron Spectrometer Model 5800 with variable angle resolution and cold finger is used to quantify the elemental composition of atoms at a surface. For example, we have used the XPS to determine the amount of surfactant trapped by polymer after admicellar polymerization. The variable angle capability means that we are able to vary the depth of penetration, i.e. we can be sensitive to the composition from approximately 1-10 nm away from the surface.

We have recently acquired a 2000 lb tester SSTM tester from United Testing Systems.We have a full range of grips and load cells for testing any kind of form a polymer can be found in, including fibers, films, dogbone bars and three-point bend. The instrument is interfaced to a computer and we can perform a wide variety of ASTM tests.

We use this instrument is used to measure Raman spectra of polymeric materials. Micron level spatial resolution is possible with the attached microscope.

The Nicolet Nexus 670 FT-IR is used to measure the infrared spectrum of many materials, including polymers. Geometries that we have used include transmission through salt plates, transmission of films and attenuated total reflectance of films. We also have a great deal of experience, although not on this IR, with infrared dichroism studies of polymer orientation..

This Waters GPC I gel permeation chromatography system is used to measure the molecular weight of polymers. We have three types of detectors: a refractive index detector, a UV detector with four user-definable wavelengths and finally a flow-through light scattering detector for absolute molecular weight determination. We are able to resolve molecular weights (polystyrene standards) from 10,000-6,000,000. We have interfaced this older unit to a IBM-type personal computer. We also have a complete GPC setup (not shown) for measuring the molecular weight distibution of water-soluble polymers.

The Cahn DCA 322 measures the dynamic contact angle between a solid surface and a liquid. The solid can be a fiber, plate or ring, and it is lowered or raised into the liquid, and the weight is measured very sensitively. We also have the automatic dosing pump (to the right of the chamber and left of the computer) to allow automatic measurement of the CMC.

The ellipsometer that is in use in our lab is from Gaertner Scientific Corporation model number L2W26C. This instrument is used to determine film thickness of nanometer to micron-thick films with angstrom level resolution. This instrument is used with an in-situ liquid cell and the associated syringe pump to measure film thickness of adsorbed surfactant layers, as well as polymeric layers after admicellar polymerization. Film thickness can be measured as a function of time, allowing us to determine the kinetics of this process

DSM 5cm3 Twin-Screw Conical Extruder--Coming Soon

The Mixer/Extruder that we use is from Design Integrated Technology Inc. model number 2CV. The CV Model is a jacketed twin cone reactor that offers a unique mixing principle using intersecting dual helical-conical blades that intermesh throughout the conical envelope of the bowl. It is designed to mix up to 12 million cps. The CV is a low speed, medium shear style rector with excellent mix dispersement. The CV is capable of full vacuum, pressure and temperature control, top loading and bottom discharging. The CV is primarily used to mix molten polymers with inorganic fillers.

The Killion Single Screw Laboratory Extruder has a 1" screw and is ideal for pound size quantities of material. The screw is designed with a special mixing section for compounding. We have a variety of heated film dies, along with a pellet die. We have a pelletizer for chopping the polymer into pellets.

The Carver Laboratory Press (picture on right) is used to take polymer pellets and make them into flat sheets using rectangular molds. Alternatively, we can use the lab press with a cylindrical mold and make a disk. We can then take these disks or sheets and, using the Dewes-Gumbs die cutter (picture on left), we can cut samples for dynamic mechanical analysis, tensile testing etc

This Keithley Model 6105 resistivity chamber, along with the associated voltage generators and current measuring devices, is used to measure conductivity of polymer composites. This cell is especially designed and shielded for low conductivity materials, and we can measure both bulk conductivity and surface conductivity. We also have home-built an apparatus (not shown) that allows us to reproducibly measure the conductivity of particulate fillers.