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The ability to measure and characterize the volumetric behavior of
new and existing materials as a function of temperature and time is of great importance. This is due to the fact that there are a variety
of physical phenomena that result in dimensional change (i.e. crystallization, melting,
glass formation, secondary transitions and physical aging).
No where is this statement more valid than in the field of polymer science.
Specific
Application
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Determination of specific volume as a
function of temperature and/or time (Vsp(T,t)).
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Determination of temperature
transitions (melt transitions (Tm), glass transitions (Tg) and
secondary transitions (Tß))
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Determination of primary
and secondary crystallization kinetic parameters.
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Determination of physical aging rates
(ßv).
Until now,
no commercially available devices existed for performing these functions, save the
following
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Density gradient columns and balance
assemblies, which allow for density characterization through buoyancy methods.
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Pycnometers that allow for the
determination of volume and thus the calculation of density through knowledge of the
initial mass and gas sorption data.
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Linear dilatometers, cylinder-piston
type dilatometers and pressure-volume-temperature (pvT) devices that rely on the
extrapolation of data to atmospheric pressure or the approximation of volumetric data from
linear data.
Limitations
associated with each of these devices leave scientists ill-equipped to determine certain
material parameters that are of extreme importance to material them. Our device circumvents the assumptions associated
with the determination of density/specific volume via the above techniques.
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Buoyancy methods and their associated
assumptions are not necessary.
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Assumptions associated with gas
sorption measurements are not necessary.
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The extrapolation of data to
atmospheric pressure or the approximation of volumetric
data from linear data is not necessary.
Technical Specifications
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An absolute accuracy of 1.0E-6 cm^3.
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Temperature control to within +/- 0.005
C.
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A sealed cell design that will allow
for ease of operation and reduce environmental concerns associated with traditional
mercury-in-glass capillary dilatometry (i.e. mercury toxicity).
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Autonomous operation and
heating/cooling linear ramp rates of up to 1C/min.
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