Chemistry Reference
In-Depth Information
Figure 8.19
Impact strength and tensile failure strain of the polymer matrices
obtained from DCPD-UPR-TO polymers with different TO contents.
due to the occurrence of phase separation and the decrease of cross-link
density, as analyzed above.
8.3.4 Structure and Properties of the Cured UPR/COPERMA
Thermosets
The physical properties of the obtained UPR/COPERMA resins are shown in
Table 8.4. It can be seen that the viscosities and gel times of the UPR/
COPERMA resins are in a range suitable for liquid molding processing.
Moreover, the addition of COPERMA into UPR reduced the linear shrinkage
of the resulting polymer matrix. This could be attributed to the abundance of
acid groups on COPERMA, which leads to better wetting and spreading in
the resin transfer molding process and good adhesion between the resins
and steel molds. The synthesized COPERMA or TOPERMA resins should be
thickened easily with divalent cations (e.g., MgO) because of the complex-
ation of MgO with their carboxylic acid groups when they are used as sheet
molding compound resins.
28
The high A
v
values of COPERMA and
TOPERMA may also increase their compatibility with some fillers, like wood
flour and some untreated reinforced fibers, due to interactions between the
acid groups and the hydroxyl groups on the surfaces of fillers or fibers.
29
The
flexural strength of the COPERMA polymer matrix was 104.6 MPa. Its tensile
strength, which was tested using a matrix cured by the same procedure
as Can et al.,
24
was about 38.5 MPa. These values are very high compared
to those of other reported oil-based monomers/styrene co-polymers.
18,22,24
