Characterization Study Guide Flashcards
State and describe a technique to measure thermal properties of polymers.
Differential Scanning Calorimetry-
the polymer is heated and as this happens the enthalpy changes… more current is required to then keep reference temperature constant. the power difference between the sample and reference is plotted against temperature.
state three advantages of SIMS and XPS for surface analysis
- high sensitivity
- more sensitive to top surface
- applicable to any solid
what principle is thermogravimetry analysis?
based on the monitoring and recording of changes in weight of a sample as it under goes controlled thermal degration. with varying temperature or time
what is gel permeation chromatography
- an extremely powerful method for determining molecular weight distribution of a polymer…
- that separates analytes on the basis of size… polymer molecules elute from the chromatography in order of decreasing molecular size
what is contact angle measurement?
- the a angle that is between the surface and a line that is tangent to a drop of liquid on the surface at the point where it intersects the surface.
if it is less than 90 degrees hydrophillic.
more than 90 degrees hydrophobic
method may tell us details about lubericity- hydrophilicty, and hydrophobicity
What are advantages and disadvantages to an invivo experiment?
Advantages- —-.better approximation to human environment
-A step often required to proceed on to clinical use.
disadvantages -costly -may take longer to test -harder to control -demanding protocols (Animal Welfare Act) -
what is atomic force microscopy?
- its a imaging method that exploits intermolecular interactions between small probe and molecules on surface
- gives good indication of surface topography/features
- through use of prob it graphs the “contact mode, intermitant contact mode, and non contact mode
when a contact angle is below 90 degrees, is it hydrophobic or hydrophillic
less than 90= hydrophillic
what does in-vitro and in vivo mean?
vitro- experiments done outside of body… example cell cultures in glass
vivo- experiment conducted inside a living organism… example animal experiments
name two techniques that could be used for structural analysis of polymers
raman spectroscopy
NMR (nuclear Magnetic Resonance Spectroscopy)
FTIR (Fourier Transform Infrared Spectroscopy (IR))
Name two techniques for surface analysis and describe the information obtained by each in this technique.
- contact angle measurments- may provide details about lubericity-hydrophillicty and hydrophobicity
- ellipsometer- may provide information of the thickness of coatings of a material
state two techniques for image analysis and describe the information obtained by each of this technique
-optical microscopy- a image is provided from a light source that is reflected/transmitted, magnification is the smallest, low resolution and depth of field. however it is the cheapest.
-SEM/EDX- scanning electron microscopy with energy dispersive x-Ray detector
- has high resolution and high depth of field. Electrons are bombarded then
reflected to portray image.
What is GPC and what information does this technique provide
Gel permeation chromotography
- an extremely powerful method for determining molecular weight distribution of a polymer…
- that separates analytes on the basis of size… polymer molecules elute from the chromatography in order of decreasing molecular size
convenient technique for characterizing the complete molecular weight distribution of a polymer.
What is XRD and what information does this technique provide
Difraction of X-Ray Crystalline Diffraction
- tell you what a materials crystal lattice structure may be….
does this by….
-bombarding x-rays on crystal structure
-based on crystal structure- x-rays are refracted
-how they are refracted gives data into peaks
-more peaks=material has more crystalline structure within the material
-get peaks and compare them to other known peaks of similar crystalline structures
