TABLE 4.1 Recent Breakthroughs in Characterization of Polymers

1.

Molecular Characterization

 

• Size exclusion chromatography, combined with light scattering and viscosity detectors

 

• Multidimensional nuclear magnetic resonance methods for determining chain architecture

 

• Millisecond time-resolved ultraviolet/visible, Fourier transform infrared, and Raman spectroscopies

2.

Solutions, Melts, and Elastomers

 

• Many new techniques for measuring diffusion

 

• Simultaneous rheological and optical/X-ray/neutron measurements

 

• New nuclear magnetic resonance and optical techniques for measuring local polymer dynamics and tertiary structure of biopolymers

 

• Neutron spin-echo techniques for measuring intermediate-scale polymer motion

 

• Neutron-scattering methods for determining the thermodynamics of polymer blends

3.

Solid-State Structure and Properties

 

• Environmental scanning electron microscopy

 

• Near-field optical microscopy

 

• Simultaneous X-ray and calorimetry measurements

 

• Solid-state nuclear magnetic resonance techniques

 

• Molecular imaging with transmission electron microscopy

 

• Confocal optical microscopy

 

• Transmission electron microscope image-processing techniques

 

• Techniques using synchrotron radiation sources for solution of the phase problem in solving the structure of large biomolecules

4.

Surfaces and Interfaces

 

• Many new deuterium depth-profiling techniques with complementary depth resolutions

 

• Surface forces apparatus to characterize the forces between adsorbed polymer layers

 

• Atomic force microscopy of surface topology

 

• Neutron reflectometry of surfaces and interfaces

5.

Biopolymers

 

• Improved separation and purification methods and capillary zone electrophoresis for separating small amounts of biopolymers

 

• Polymerase chain reaction technique for amplifying very small quantities of DNA

 

• Multidimensional nuclear magnetic resonance methods for obtaining high-resolution structures in solution

 

• Mass spectroscopy that quickly sequences biomolecules

 

• Computer database technology for comparing informational macromolecules

of polymers can depend not only on the averages, but also on the polydispersities of the attributes just mentioned, it is necessary to characterize all of these. Methods for determining average molecular weights of soluble polymers and some of the other average properties are well known, but characterization methods for the distribution of these properties, especially for more than one of these properties at a time, are in short supply.



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