Advances in Materials Physics and Chemistry, 2011, 1, 94-98
doi:10.4236/ampc.2011.13016 Published Online December 2011 (http://www.SciRP.org/journal/ampc)
Initial Study of Electrospinning PCL/PLLA Blends
Guinea B. C. Cardoso, Geraldine N. R. Perea, Marcos A. D’Avila, Carmen G. B. T. Dias,
Cecília A. C. Zavaglia, Antonio C. F. Arruda
Materials Engineering Department, Faculty of Mechanical Engineering, State University of Campinas,
Campinas, Brazil
Received September 7, 2011; revised October 13, 2011; accepted October 24, 201 1
Abstract
The process of electrospinning is considered one of the most promising methods for the fabrication of poly-
mer nanofibers. This essentially consists of applying a high electric field, which causes stretching of the
polymer which exits through a capillary. Among the numerous applications of this process, electrospinning
allows the fabrication of semiconductor and conductive nanofibers from mixtures or solutions, which have
great potential for applications in sensors and the fabrication of scaffolds for cell growth. The aim of this
work was to analyze the properties of the blend, produces by the electrospinning of the PCL and PLLA solu-
tion, with the focus to generate a promissory scaffold. PCL is a semi-crystalline aliphatic polymer that has a
slower degradation rate 12 - 24 months. It has a low glass transition temperature at –60˚C, a melting tem-
perature at about 60˚C, and a high thermal stability. Properties of PLA depend on the component isomers,
processing temperature, annealing time and molecular weight. Thus were used PCL, from Aldrich, with Mw
of 80,000 g/mol, and PLLA, sintered in laboratory, with Mw of 240,000 g/mol, were dissolved in chloroform
(CHCl3, Merck) and acetone (Synth) by stirring for 6 hours. The solution was electrospinning for 1 hour us-
ing the equipment made in the laboratory, the voltage used was 13 kv, the rate of 0.5 ml/h and an approxi-
mate distance from the tip of the needle to the collector of 12 cm. The morphology of the samples was ob-
served by images made with scanning electron microscopy (SEM) and also was analyzed by FT-IR and
DSC.
Keywords: Polymers, Poly (ε-Caprolactone), Poly (L-Lactic Acid), Electrospinning
1. Introduction
Tissue engineering can be defined by Langer and Va-
canti, as “an interdisciplinary field that applies the prin-
ciples of engineering and the life sciences toward the
development of biological substitutes that restore, main-
tain or improve tissue function” [1].
Tissue engineering strategies aim for mimicking the in
vivo process of bone repair in a laboratory setting. The
three key elements for generating bone tissue, namely
osteogenic progenitor cells, osteoinductive growth fac-
tors and osteoconductive matrices are involved in this
process.
Scaffolds are temporary matrices for bone growth and
provide a specific environment and architecture for tissue
development. The material composition as well the
structural characteristics such as external and internal
design are putatively crucial for the successful outcome
of all scaffold-based bone tissue-engineering strategies.
Recently, the effects of the nano or micro structure
surface features of the various cells have been examined.
Some researchers have found that in the micro structured
surface environment, increasing the surface roughness by
sand-basting can affect the production of growth factors
and the number of osteoblast like MG-63 on a titanium
surface, or promote cell adhesion and migration on a
PMMA surface [2,3].
Some methods to fabricate scaffolds are electrospin-
ning, solvent casting, fiber bonding, phase separation,
gas induced foaming, salt leaching, 3D printing, selective
laser sintering, multi-phase jet solidification and others
[4-8].
Electrospinning, has attracted a lot of attention due to
its relative simplicity regarding the generation of fibrous
scaffolds with nanoscale dimensions. Electrospinning
utilizes electrostatic forces to spin polymer solutions or
melts into whipped jets, producing continuous fibers
with diameters from a few nanometers to micrometers

G. B. C. CARDOSO ET AL.95
after solvent evaporatio n in the spinning process [9,10].
Polymers are organic or inorganic materials, whose
structures are composed of repeating units, the mere
linked by covalent bonds. Among the polymers that are
used for more than two decades in the medical field, are
the poly (α-hydroxy acids), which is considered one of
the most promising family of polymers in the area of
bioresorbable. Its great advantage in this form of degra-
dation occurs by hydrolysis of their ester bonds. As an
example, poly (L-lactic acid) (PLLA), poly (glycolic acid)
(PGA) and poly (ε-caprolactone) (PCL), these sub-
stances obtained approval by the Food and Drug Ad-
ministration (FDA).
The poly (ε-caprolactone) (PCL) has been used in
many researches because of its biodegradable, biocom-
patible properties and also has the approval of US Food
and Administration (FDA). PCL is a semi-crystalline
aliphatic polymer that has a slow degradation rate 12 - 24
months. It has a low glass transition temperature at
–60˚C, a melting temperature at about 60˚C, and a high
thermal stability [11].
Poly (L-lactic acid) (PLLA) has been used in many
researches because the characteristics o f biocompatibilit y,
degradation and absorption in aqueous absorption in
aqueous medium, also has the approval of US Food and
Administration (FDA). PLLA is a semicrystalline poly-
mer with a melting point around 170˚C and a crystallin-
ity around 70%, making it among the poly (lactic), which
has the lowest rate of degradation.
By using only one type of polymer for the fabrication
of scaffolds is often not attained all the necessary char-
acteristics for a given clinical application. Thus, research
has been directed to study blends, copolymers and com-
posites that improve the fundamental properties of scaf-
folds, such as permeability, absorption and elastic prop-
erties [12].
The use of PLLA and PCL display important proper-
ties regarding degradation rates, porosity and resistance
to stress. Also, a critical characteristic is that they can be
molded in different sizes and shapes. In this work the
aim was to produce a blend of polycaprolactone and poly
(L-lactide) using the method of eletrospinning for a pro-
duction of scaffold. The blends were fabricated using
poly (ε-caprolactone) (PCL, from Aldrich), with Mw of
80,000, and poly (L-lactide) (PLLA, sintered in labora-
tory).
2. Materials and Methods
2.1. Preparation of the Solution
The polymer PLLA was synthesized by opening of cy-
clic dimer of lactic acid (lactide), with the objective of
obtaining high molecular weight polymer [13].
The blend was made using poly (ε-caprolactone) (PCL,
from Aldrich), with Mw of 80,000 g/mol, and PLLA,
with Mw of 240,000 g/mol, was dissolved in chloroform
(CHCl3, Merck) and acetone [(CH3)2CO, Synth] with a
rate of 25/75 wt%, respectively. The mixtures were stir-
ring during 6 hours [14].
2.2. Eletrospinning Process
The solution was electrospinning for 1 hour using the
equipment made in the laboratory, the voltage used was
13 kv, the rate of flow of 0.5 ml/h and an approximate
distance from the tip of the needle to the collector of 12
cm. The different percentages of PCL/PLLA were sam-
ple 1 25/75 wt%, sample 2 50 wt% and sample 3 75/25
wt%.
2.3. Instrumental Characterization
The morphology of the samples was observed by images
made with scanning electron microscopy (SEM) using
the equipment Jeol (JXA 840 A, Brazil). The average
were produce by the analysis of 8 wires in each sample,
and also were calculated the standard deviat ion.
The samples were also analyzed by Fourier Transform
Infrared Spectroscopy (FTIR) the blends of PLLA/PCL
were analyzed by infrared spectroscopy of the average
(4000 to 500 cm–1). The transmission spectra of samples
were obtained in the form of KBr pellet using THERMO
SCIENTIFIC NOCOLET IR100 spectrometer.
In the analysis of differential scanning calorimetric
(DSC), the thermal properties of the blends of PLLA/
PCL studied were determined using the equipment MET-
TLER TOLEDO DSC 823e. The samples were weighed
into an aluminum sample port of cylindrical and her-
metically closed. The test for the dynamic method was
performed under nitrogen atmosphere at 45 mL/min and
two scans temperature range:
 First scan of 0˚C to 300˚C at a ra te of 10˚C/min;
 Second scan of 0˚C to 300˚C at a rate of 10˚C/min;
interspersed with a cooling rate of 20˚C/min.
3. Results and Discussion
Biopolymer films are modified to promote cell growth
for tissue engineering can be generally categorized using
two types of approach. First, bioactive components such
as hydroxyapatite particles are incorporated into polyesters
by co-polymerization or blending. Second, the biopo-
lymers with the nano rough surfaces can be fabricated
using various techniques, such as the addition of surfac-
tants (e.g. Span 80, Sigma) and others reagents ( e.g. w at e r)

G. B. C. CARDOSO ET AL. 96
at the polymeric solution. For example, Mo X et al.,
reported that the emulsion fabricated by the eltrospinning
of poly (L-lactide-co-ε-caprolactone), Span 80 and dis-
tilled water produces samples with a surface that shows
to have influence into the pro liferation an d cells adh esion
[15].
3.1. DSC
The DSC analysis confirmed the blend of those polymers,
in all the heating the peaks showed in the same tempera-
ture, therefore those polymers combined just physically,
showed in the Figure 1.
The red line, sample with more PCL percent, presents
the peak of Tm more defined, when compared with the
sample with more PLLA in your composition, blue line,
which present an exothermically peak, because the in-
teraction of PLLA to PCL. The sample with 50% of PCL
and PLLA showed the peak in the middle of both sam-
ples.
3.2. IF-TR
Figure 2 shows the spectrum of PLLA at green line. All
the samples were dislocated 300 cm–1. Therefore the
peak at 2995 cm–1 corresponds to alkane stretch (C-H).
The C=O peak is at 1750 cm–1 while peak at 1187 cm–1 is
for C-O group. Figure 2 shows spectrum of PCL red line.
The O-H bond is at 3443 cm–1. The peaks appearing at
2943 and 2866 cm–1 are due to the C-H stretching. The
peak at 1724 cm–1 is due to the C=O bonding. The C-O
bending is at 1167 cm–1.
Figure 3 shows the spectrum of the polymer blends
(PLLA/PCL). The peak at 3358 cm–1 corresponds to O-H
bond. The C-H stretching is at 2992 and 2945 cm–1. The
peak at 1747 cm–1 is due to the C=O bonding and at 1184
cm–1 corresponds to the C-O bending. These groups indi-
cate the presence of both polymers (PLLA/PCL) in the
blends.
Figure 1. DSC of the samples: 1-blue; 2-green; and 3-red.
Figure 2. FT-IR of the samples green line—PLLA and red
line—PCL.
Figure 3. FT-IR of the samples: 1—red line; 2—purple; and
3—blue.
3.3. Morphology
The morphology of the different blends was showed in
the Figure 4. It is clear the alteration of the diameter of
the wires. In the Figure 4 (1B) the wires were showed an
average of 1.31 µm, this value showed near the Figure 4
(3B), where the media was 1.37 µm. However, when
produce the blend with equal proportion of PCL and
PLLA, the average showed lower, as 0.79 µm, that’s
possible by the solution presents characteristics indicated
for electrospinning. Also, in the Figure 4 (2B), it is pos-
sible to observe the morphology of the wires when con-
tact with other, in those intercession s present more adhe-
sion of the polymers.
The structural and functional properties of the natural
extracellular matrix (ECM) are crucial for the prolifera-
tion, differentiation and migration of cells. As a cones-
quence, there is an increasing tendency to design scaffold
materials, as applied in tissue regeneration approaches,
according to the characteristics of the ECM. The angle of
contact can be very useful for the adhesion and prolifera-
tion of cells, therefore is very important to study this
aspect, which will be the aim in th e next approach.
4. Conclusions
The use of biomaterials has been regarded as an efficient
alternative to the allograft, since it significantly reduces
the risk of rejection and local inflammation. Also, the
method of preparation of the biopolymer together with it
properties may influence in the degradation rate, flexibil-

G. B. C. CARDOSO ET AL.97
1A 1B
2
A
2B
3
A
3B
Figure 4. SEM images of the different samples: (1) sample 1;
(2) sample 2; and (3) sample 3; using (A) 1000x and (B)
5000x.
ity and cell adhesion.
The both polymers PCL and PLLA either alone or
combined as blends or co-polymer, are approved by the
Food and Drug Administration, therefore those polymers
have been extensively used in tissue engineering due to
their advantages of wide availability, ease of processing,
adjustable degradatio n and mechanical properties.
In this paper was observed the influence of the blend
composition into the fiber morphology, the fibrous mat
with high porosity were successfully obtained by elec-
trospinning, showing the potential use of electrospinning
to fabricate scaffolds for tissue engineering.
However are necessary others experiments to deter-
mine the effect of the blend composition into the degra-
dation rate and also the initial influence of the surface of
the fibers.
5. Acknowledgements
This work was support mainly by FAPESP project num-
ber 2009/54546 -9. The eq uipment sup por ts were especial
with the grants of CAPES and CNPq.
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