Biomedical Engineering Reference
In-Depth Information
z
Polymer solution
x
y
Solution bath
Fibres
Fibre
dispensing
head
Rotating
mandrel
2. Solvent/non-solvent exchange
1. Filament winding
(a)
Solvent
Calcium phosphates
(HA, TCP)
Porogen agent
(NaCl)
Polymer
Petri dish
T
f
2. Addition of bioactive signals
3. Solvent/non-solvent extraction
1. Solution preparation
(b)
9.3
Scheme of preparation of different typologies of composites.
(a) fibre reinforced composites; (b) inorganic filler reinforced
composites.
integration of hydrophilic PLA continuous fibres into a hydrophobic PCL matrix
in order to obtain highly porous scaffolds for bone regeneration (Guarino
et
al
., 2006). In these fibrous composites (Fig. 9.4a), degradation preferentially
occurs at the fibre-polymer interface, resulting in a higher rate of degradation
than for either material alone. usually, the characteristic degradation rate
of composites is too high and not totally adequate for clinical applications
such as bone fracture fixation which require strength retention in the long
term (i.e few weeks up to several months). However, a continuous fibre
reinforced composite made of two interconnecting phases which mimic the
bone structural organization better, assures a strong mechanical interlocking
between two phases which, in turn, assures the retention of some of its
properties if breakdown occurs at the interface. The main difficulty in the
design of composite materials is referred to the optimization of the adhesion
between matrix and reinforcement. an interfacial bond able to promote
