Biomedical Engineering Reference
In-Depth Information
Figure 4.2
Gel permeation chromatograph of reaction products between lactide and TEG.
Reprinted from [17], p. 1022, with permission from Elsevier.
120
100
80
60
40
20
0
0
10
20
30
40
50
60
70
80
90
100
Hexane diol (%)
Figure 4.3
Glass transition temperature of 3,9 - diethylidene - 2,4,8,10 - tetraoxaspiro [5.5]
undecane,
trans -
CDM, HD polymer as a function of mol% HD.
ranging from hard, solid materials to viscous ointment-like materials can be
prepared.
One of the more useful methods of achieving control over mechanical properties
is to use a mixture of a rigid diol, for example,
trans
- CDM, and a fl exible diol, for
example, HD. When the glass transition temperature is determined for mixtures
ranging from pure rigid diol to pure fl exible diol, the plot shown in Figure 4.3 is
obtained [18]. When linear, aliphatic diols having varying number of methylene
groups are used, the plot shown in Figure 4.4 is obtained [19].
Figures 4.3 and 4.4 have been generated with POE II that has no latent acid in
the polymer backbone. When POE IV is used, the latent acid in the polymer back-
bone does have a signifi cant effect on the glass transition temperature, as shown
