On Morphology of Polyhydroxybutyrate - Progress in Organic and Physical Chemistry: Structures and Mechanisms - page 237

can proceed to a lesser degree owing to presence in ¿ lms PHB of crystallites with the
defective structure, having the downgraded melting point, see Figure 1.

FIGURE 1 Thermograms of heating of films on the basis of PHB.
a = initial PHB
b = PHB from dioxane
c = PHB from chloroform
d = PHB from formic acid
e = PHB from dichloroethane

TABLE 1 Therm al characteristics PHB films from various solvents.

Solvents Δ G m , J/g Ɍ m , ɨ ɋ Ɍ g , ɨ ɋ ɋ ɪ ,

J/g Ʉ

Δ μ , D ɟ 1/2

Polymer films parameters Solvents characteristics
dioxane - 0,076 174,3 63,0 0,39 0,45 10,05
chloroform - 0,140 175,6 53,9 0,24 1,15 9,3
formic acid - 0,106 176,2 - - 1,4 13,5
dichloro-ethane - 0,173 178,5 74,0 0,1 2,06 9,0
'G m , J/g - Gibbs energy melting; Ɍ m , ɨ ɋ - melting temperature; Ɍ g , ɨ ɋ - glass-transition
temperature; 'ɋ ɪ , J/g Ʉ - specific heat;P, D - dipole moment - [9, 10]
ɟ 1/2 - cohesions energy density - [8].