Preparation And Characterizations Of Poly(L-Lactic Acid) (Plla) Blends And Plla Scaffold
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Date
2011-02
Authors
Vannaladsaysy, Vilay
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Optimization of poly(L-lactic acid) (PLLA) blends was carried out by
blending with ductile biopolymers such as poly(ε-caprolactone) (PCL),
poly(butylene succinate-co-L-lactate) (PBSL) and poly(butylene succinate-co-ecaprolactone)
(PBSC) and addition of compatibilizer such as lysine triisocyanate
(LTI) and polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPOPEO)
triblock copolymer. Preparation of PLLA based scaffold was also been
considered in the present study. In the first series, the effects of blend composition
(100/0, 90/10, 80/20, 70/30, 50/50, 25/75 and 0/100 wt%) on the morphological,
mechanical and thermal properties of PLLA/PCL, PLLA/PBSL, and PLLA/PBSC
blends were carried out. It is found that the bending properties decreased with
increasing PCL or PBSL or PBSC contents. This was traced by the poor interfacial
adhesion between PLLA and PCL or PBSL or PBSC as observed in the phase
separation morphology. The second series were on the effects of LTI content on the
properties of PLLA/PCL blends. The mechanical properties of the PLLA/PCL blends
were observed to increase with the presence of LTI with optimum properties shown
at LTI loading of 5phr. This was attributed to the interaction between isocyanate
group of LTI and OH group of both PLLA and PCL. The compatibilizing effects of
LTI content on the PLLA/PCL blends were proven by moderate improvement in the
fracture toughness and confirmed by the ductile morphology as observed by the FESEM.
The fractured energy values of the PLLA/PCL blends increased with the
increasing of LTI contents. The optimum toughening effect was observed in
PLLA/PCL (50/50) blend compatibilized with LTI at 5phr. In the third series, the
effects of addition of PEO-PPO-PEO triblock copolymer contents (0.5, 1 and 2phr)
into PLLA/PCL (70/30 wt%) were carried out. The addition of the copolymer into
the PLLA/PCL improved its fracture toughness. The glass transition temperature (Tg)
and melting temperature (Tm) of PLLA and PCL shifted slightly closer together,
indicating that the blend miscibility slightly increased and hence increased mode I
fracture properties. In addition, solid-liquid phase separation and freeze-drying
techniques (SPS-FD) is able to be used in preparing highly porous scaffolds with
higher compression property. With this fabrication technique, highly porous and
interconnected PLLA scaffolds were successfully fabricated, suggesting that PLLA
concentration below 10 wt% exhibits great potential for tissue engineering
applications.
Description
Keywords
Poly(L-Lactic Acid) (Plla) Blends , And Plla Scaffold