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Analytical
Services Testing Laboratory Techniques
2 Dimensional Chromatography
Conventional GPC,
SEC, GFC Chromatography
Light Scattering Coupling
with Conventional GPC, SEC, GFC Chromatography
Viscometry Coupling with
Conventional GPC, SEC, GFC Chromatography
High Temperature GPC
Static Light Scattering
Static Viscosity
Vapour Pressure Osmometry
2 Dimensional Chromatography
This method is useful for analysis of complex polymer systems like
polymer blends, copolymers and branched polymers. These samples
are usually heterogeneous in terms of chemical composition,
functionality and structure. Since GPC separates only according to
size, GPC is not sufficient to describe such a system. Therefore,
the combination of two chromatographic methods to separate the
mixture into more homogeneous fractions (i.e., functional groups)
followed by separation by molar masses constitutes a better
approach. WINGPC software allows the automatic transition from
one dimension to the other. PSS offers the development of 2-D
applications and performs the analysis for you, with our special
software for data acquisition, quantitative interpretation and data
plotting, the WINGPC 2D module.
Results provided to the client:
* complete deformulation
* composition
* molecular weight distribution
* molecular weight averages, Mw, Mn, Mz
* copolymer composition
For more information about the principles and use of 2D
chromatography see:
"Facing
the Challenge of Analyzing Complex Polymers: A Primer in
2Dimensional Liquid Chromatography"
Conventional GPC, SEC,
GFC
Chromatography
Order
Testing
Conventional GPC is an excellent method for sample comparison and the
determination of molecular weight of a sample. Conventional GPC
analysis yields the complete molar mass and is more reliable and
informative than a method that only yields an average value (Mw or
[h]). PSS offers testing in aqueous and organic mobile
phases. Customer requests are usually honored. As a manufacturer
of a great variety of polymer standards, PSS is able to use
the optimum standards to characterize your samples. Before
each measurement series, the analytical system is validated and
calibrated with a 9 data point calibration. An internal
standard is used to monitor the constant flow of the pump and for
flow-correction as needed. Afterwards the molecular weight
distribution is calculated from the elugram using the
corresponding calibration curve.
Calculation of the percentage of a given molar mass (eg. < 500
g/mol) from the molecular weight distribution is usually
requested for product approval in the USA. Additives and
stabilizers can be separated from the polymer and a quantitative
determination of these compounds is possible. The analysis report
lists all relevant parameters of the measurement and
documents the sample preparation.
Results provided to the client:
* simple comparison of polymer samples
* molecular weight distribution
* molecular weight averages: Mw, Mn, Mz
* percentage of mass, eg. < 500 g/mol
* chemical composition
FTIR Coupling with Size Exclusion
Chromatography
Order
Testing
FTIR is used to identify chemical substances. The coupling of
liquid chromatography (LC) with Fourier-Transform-Infrared (FTIR)
spectroscopy allows the identification of unknown fractions
with the help of a spectra database. When used in combination
with a chromatographic system, the substrate is collected
on a rotating Ge-disk. FTIR-spectra can be gained for each
point of the chromatogram. PSS uses a special interface to remove
the solvent on-line after the chromatographic separation is
done. This method allows for identification of the substance as well as
for the evaluation of chemical heterogeneity.
Results provided to the client:
* chemical structure - chemical purity
* information about additives
* chemical composition
Light Scattering Coupling with
Conventional GPC, SEC,
GFC Chromatography Order
Testing
The light scattering detector provides absolute molar masses without
requiring the appropriate polymer calibration standards. The GPC
separates the sample by size and the online light scattering
detector directly determines the molar mass. You get the absolute
weight average (Mw) and molecular weight distribution of the
polymer. The method is limited by the molecular weight of the
sample (depending on the type of polymer), the minimum molar mass
normally has to be above 5000 g/mol. PSS uses a low angle (LALLS)
and a multi angle light scattering detector (MALLS) during routine
operation. The MALLS detector provides additional information
about the radius of gyration, which is derived from the angle
dependency of the scattered light. From the combination of
absolute molecular masses and corresponding radius of gyration, it
is possible to obtain important structure information and
branching.
Results provided to the client:
* molecular weight distribution
* absolute molecular weight average Mw
* radius of gyration
* branching / structure information
Viscometry Coupling with
Conventional GPC, SEC, GFC
Chromatography Order
Testing
The capability to get exact molar masses without having the proper
polymer standards is offered by online viscosity detection. This
method uses the concept of universal calibration and provides the
correct masses, the molecular weight distributions, and information
about the structure of the polymer. With viscosity detection you
can also analyze small molecules (e.g. oligomers), a big
advantage over online light scattering measurements.
The GPC - viscosity coupling allows you to determine the important
relationship between intrinsic viscosity and molar mass of a
polymer within one measurement. From this data, you can calculate
the Mark-Houwink parameter of the investigated polymer - solvent system
containing the structural information.
Results provided to the client:
* intrinsic viscosity
* Mark - Houwink parameter
* molecular weight distribution
* molecular weight averages, Mw, Mn, Mz
* branching / structural information
High Temperature
GPC Order
Testing
Some polymers are insoluble at room temperature. Polyolefins and
their co-polymers are soluble at temperatures over
130°C. PSS offers testing of polymers soluble in
1,2,4-trichlorobenzene at 155°C, using a Waters 150C HT-GPC
system equipped with a refractive index detector, a viscosity
detector, a FTIR-coupling interface and a column- switching
system that permits the use of 4 different polefin-columns.
This gives us the possibility to run polyolefins in a range
from hundreds to more than 20.000.000 g/mol. We can offer you
a standard calibration with polystyrene or polyethylene or
a universal calibration using a differential capillary viscosity
detector
Static Light
Scattering Order
Testing
Static light scattering is an established and exact method for the
absolute determination of the weight average molar mass (Mw) of a
polymer. The measurement is carried out without separation of the
polymer solution in a light scattering cell. The measured
quantity is the intensity of the scattered light (Excess-Rayleigh
scattering), which is proportional to the average molecular size
of the dissolved substance. A series of measurements, performed
with different concentrations (c) at various scattering angles (theta),
results in the weight average molecular mass Mw. One requirement
is the knowledge of the refractive index increment (dn/dc) of the
polymer in the solvent used. The molecular weight average Mw is
determined with by plotting the data and extrapolation of c and
theta to zero (Zimm-plot). Another parameter derived from the Zimm -
plot is the second virial coefficient B.
Results provided to the client:
* absolute molecular weight average Mw
* radius of gyration
* second virial coefficient B
Static Viscosity
Viscosity measurements have a special significance in the quality
control of polymers. These measurements, performed under
standardized conditions (DIN, ASTM etc.), provide important
parameters e.g. for polymer processing. The method in general averages
over the whole sample, producing integral values as a
result. PSS is able to determine various kinds of viscosities,
e.g. relative viscosity, inherent viscosity, intrinsic viscosity
etc., even in uncommon solvents like HFIP, meta-Cresol, ortho-
Dichlorobenzene and formic acid at temperatures up to 302°F (=
150°C).
Results provided to the client:
* absolute, relative, inherent and intrinsic
viscosities
* Huggins / Krämer constants
Vapour Pressure
Osmometry Order
Testing
The molar mass determination by osmometry is one of the most important
methods for evaluating the number average molecular weight Mn.
This is an important parameter for the interpretation of kinetic
data in polymerization and copolymerization reactions. The method
is also of interest for prepolymers with lower molar masses. PSS
provides sample testing service using vapour pressure osmometry
measurements of polymers with masses Mn < 10000 g/mol in
toluene and ultra pure water. A run includes the determination of the
device scaling factor and the measurement at four different s
ample concentrations. The number average molecular weight Mn and
the second virial coefficient B is evaluated graphically.
Results provided to the client:
* number average molecular weight Mn
Confidentiality Agreement
If you have confidentiality
requirements, we routinely deal with this
kind of situations. Just email your agreement requirement and we
will promptly process it. contact us for
more info.
Ordering Laboratory Services
- Fill out the Sample Testing Evaluation
Form.
- Place the order
- Ship the samples, the Sample Testing
Evaluation Form and (if available) the sample MSDS to:
Polymer
Standards Services USA, Inc
Amherst Fields Research Park
160 Old Farm Rd, Suite A
Amherst, MA
01002
- Receive your results via e-mail, 10
days from PSS receipt of your sample
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