RAMAN APPLICATION IN EMULSION POLYMERIZATION SYSTEMS - Raman Spectroscopy for Soft Matter Applications - page 118

Table 5.5 Monitoring other polymerization processes

Instrument/
Calibration
details

Reference
no.

Process/Goal Monitored property

Suspension
polymerization/PSD
has a strong impact
on properties and
must be controlled
during polymerization

Monomer concentration
(homopolymerization)
Particle size (micron
range)

FT - Raman, NIR
excitation
(1064 nm)
Spectral region
below
600 cm − 1

3 6

Microemulsion
polymerization/Very
compartmentalized
system, very fast
kinetics and diffi cult
to monitor

Monomer concentration
(homopolymerization)

Dispersive
Raman
(514 nm)
Univariate

6 6

Anionic dispersion
polymerization

Monomer concentration
(block copolymers of
styrene - butadiene)
Polymer composition
(polybutadiene)

FT - Raman, NIR
excitation
(1064 nm)
In - house least -
square
method

6 7

Encapsulation/
Production of
microcapsules that
contain gas, solid, or
liquid in different
shell materials

Encapsulation effi ciency
(quantifi cation of
encapsulated epoxy
resin amount)

FT - Raman, NIR
excitation
(1064 nm)
Univariate
(relative peak
intensities)

68 and 69

PSD, particle size distribution; FT, Fourier transform; NIR, near-infrared.

resin in a urea-formaldehyde shell have also been reported. Additional
details about these processes are given in Table 5.5.

5.4 OTHER APPLICATIONS

5.4.1 Monomer Partitioning

A very important feature in heterogeneous systems is the monomer
partitioning between the different phases (water phase, monomer drop-
lets, and polymer particles). The polymerization rate, initiator effi ciency,
radical transfer, and copolymer composition are directly affected by the
monomer concentration in the polymerization loci. Therefore, under-
standing and measuring monomer partitioning is of great interest in
understanding and modeling kinetics of emulsion polymerization.