14 Polymer Characterization

Question 1

GPC

Answer 1

Gel permeation chromatography (size exclusion)

different
molecular weights separated by
hydrodynamic volume.

porous beads.

Question 2

GPC Standardization

Answer 2

Standards are used

standard should have similar chemical and physical
characteristics as the polymer and have a narrow MW distribution

Question 3

DSC

Answer 3

Differential scanning calorimetry

heat required to keep a material and a standard at
a constantly increasing temperature is monitored.

Note that temperature does NOT change during a
phase transition

DSC can be used to determine the temperature at which
phase transitions occur. Tm, Tg
, Tcryst, heat capacity

Question 4

Heat capacity

Answer 4

Heat capacity can be calculated by dividing the
heat flow at a given temperature by the heating
rate. = q/change T

Question 5

TGA

Answer 5

Thermogravimetric analysis

The weight of a sample is monitored as the
temperature is increased. The atmosphere is
controlled (i.e. ambient, nitrogen, argon, etc.).

Question 6

Meso and Racemo diads NMR

Answer 6

Two repeat units in a polymer are called diads.

meso = same side
racemo = opp