ELECTROSPUN NANOHYBRID MEMBRANES BASED ON BIORESORBABLE POLYMER AND CARBON NANOSTRUCTURES

VI Convegno Nazionale sulla Scienza e Tecnologia dei Materiali

ELECTROSPUN NANOHYBRID

MEMBRANES BASED ON BIORESORBABLE

POLYMER AND CARBON NANOSTRUCTURESIlaria Armentano, Alessandra Bianco, Costantino Del

Gaudio, Mariaserena Dottori, Francesca Nanni, Josè Maria Kenny.

Materials Engineering Centre, UdR INSTM, NIPLAB, University of Perugia, Terni,

Dip. di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica, Roma, 00133 (M) -

ITALY


AimAim

The purpose of this study was to investigate nanohybrid systems based on bioresorbable Polymers and CNSs, in different Morphological structures.

CompositionMorphology


Outline

State of the artMaterials & Methods

Nanocomposite Development: Membranes & Film

Nanocomposite Charaterization: Morphological & Thermal & Dynamo-

MechanicalConclusions


Bioresorbable PolymersBioresorbable Polymers

NANOCOMPOSITE

O CH2 C

O

n

PGA

O CH

CH3

C

O

n

PLA

O CH2 C

O

n

PCL

PLA-PGA

PLA-PCL

•Chen G-X, Kim H-S, Park BH, Yoon J-S. Controlled Functionalization of Multiwalled Carbon Nanotubes with Various Molecular-Weight Poly(L-lactic acid)., J Phys Chem B 2005;109:22237-22243.• Zhongkui Honga, Xueyu Qiua, Jingru Suna, Mingxiao Denga, Xuesi Chena,b,*, Xiabin Jinga Grafting polymerization of L-lactide on the surface of hydroxyapatite nano-crystals, Polymer 45 (2004) 6699–6706


Carbon Nanotubes Carbon Nanotubes tubes made of a single sheet of graphene (SingleWallNanoTube)or more sheets (MultiWallNanoTube)

The regular geometry gives CNT excellent

mechanical and electrical

properties.

CNT diameters are in the range 1 - 500 nm; CNT lengths can range from several µm to mm.Richard Smalley: “These nanotubes are so beautiful that they must

be useful for something.”


CNTsCNTs Why CNTs? Extraordinary properties

Structure Nano and um dimensions High aspect ratio: 1000 High specific surface area: 1400m2/g High ratio interfacial area/vol: 1000 um-1

Large number density/vol: 106 CNTs/um3

Size scale comparable to interface layer (1-10 nm)

Chirality based on rolling direction Found as single wall and Multi wall tubes

Unique Structure

http://cohesion.rice.edu/naturalsciences/smalley/emplibrary/ropes_5.jpg


Mechanical Properties

SWNTs: 0.32-1.47 TPa (100 x steel) 0.5-5.5 TPa SWNTs Bundles: 230 Gpa

Young’s modulus

CNTs Fibres

Light, strong and highly flexible material

Vigolo B,Pe ｴ nicaud A,Coulon C,Sauder C,Pailler R,Journet C al.Macroscopic .bers and ribbons of oriented carbon nanotubes.Science 2000;290:1331.

*C.A. Dyke and J.M. Tour. Covalent Functionalization of Single-Walled Carbon Nanotubes for Materials Applications. The Journal of Physical Chemistry, 2004.


ElectroSpinningElectroSpinning

A typical electrospinning set-up using a grounded static collector.

Nanotechnology 17 (2006) R89–R106 WETeo and S Ramakrishna

Nanofibres

> 5 kV

Experimental conditions:

•Solution viscosity

•Molecular weight

•Voltage

•Solvent

Fibres Diameter

DCThe formation of nanofibres through electrospinning is based on the uniaxial stretching of a viscoelastic solution.

A high voltage is applied to the solution such that at a critical voltage, typically more than 5 kV, the repulsive force within the charged solution is larger than its surface tension and a jet would erupt from the tip of the spinneret.


Materials

ε-PCL

Sigma AldrichSigma Aldrich

Polymer Matrix

MethodsSolvent

Casting in CHCl3

CNFs: Carbon NanoFibers, Pyrograf

SWNTs: Single Wall Carbon Single Wall Carbon Nanotubes, Thomas Swan Nanotubes, Thomas Swan & Co.Ltd.

Electrospinning

CNSs

Flat Film d=200

µm

Porous Membranes

1 % wtO CH2 C

O

n

•Chen G-X, Kim H-S, Park BH, Yoon J-S. Controlled Functionalization of Multiwalled Carbon Nanotubes with Various Molecular-Weight Poly(L-lactic acid)., J Phys Chem B 2005;109:22237-22243.• Zhongkui Honga, Xueyu Qiua, Jingru Suna, Mingxiao Denga, Xuesi Chena,b,*, Xiabin Jinga Grafting polymerization of L-lactide on the surface of hydroxyapatite nano-crystals, Polymer 45 (2004) 6699–6706

&

MW 80000


SWNTs

0 100 200 300 400 500 600 700 800 900

0

20

40

60

80

100

Air

T [°C]

Re

sid

ua

l Ma

ss [

%]

0.00

0.02

0.04

0.06

0.08

0.10

0.12

DT

G [g

/g m

in]

FESEM - Zeiss Supra25Seiko exstar 6000

T=555°C Residual Mass=3% Metal catalist

PURITY

TGAIn Air 5°C/min (30-1000)°C

TG and derivative oxidation thermograms of pristine SWNTs

SEM image of the specimen of pristine SWNTs cross linked bundles


CNFsCarbon Nanofibers

0 200 400 600 800 1000 1200

0

20

40

60

80

100890 °C

0.6%

CNFs

T [°C]

Res

idua

l Mas

s [%

]

-0.01

0.00

0.01

0.02

0.03

0.04

0.05

0.06

DT

G

TGAIn Air 5°C/min (30-1000)°C

FESEM - Zeiss Supra25Seiko exstar 6000


Morphological AnalysisMorphological AnalysisField Emission Scanning Electron Microscopy FESEM-Supra 25 Zeiss

PCL Membranes


CONTACT ANGLEFTA 1000 AnalyserSurface Characterization

(118± 1)°

PCL Membranes PCL Film

hydrophobic surface

Water

(74.5± 0.5)°

Materials Water Contact Angle

PCL (74.5± 0.5)°

PCL+1%SWNTs

(74.2± 0.5)°



Film, fracture surface PCL+ CNFs 1% wt



Film, fracture surface PCL+ SWNTs 1% wt



Nanohybrid Membranes PCL+ CNFs 1% wt

Surface



Nanohybrid Membranes PCL+ CNFs 1% wt

Cross Section



Nanohybrid Membranes PCL+ SWNTs 1% wt

Surface


Dielectric Dielectric CharacterizationCharacterization

101

102

103

104

105

106

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

AC [

S/m

]

[Hz]

PCL PCL SWNTs 0,1% PCL SWNTs 0,75% PCL SWNTs 1%

HP4284 20 Hz-1MHz

A

d

Z

1

Specific bulk AC conductivity and dielectric constant as a function of frequency for PCL based nanocomposite films with different nanofiller content.

Characterization of conductivity of CNSs/polymer materials:

An introduction of carbon nanotubes in the polymer matrix is expected to influence the strength and the electrical conductivity of the nanocomposite.

Cu

CuPCL Nanocomposite


Thermal CharacterizationThermal CharacterizationDSC

The samples were heated from -25 to 100°C at a scanning rate of 10°C/min. Two heating cycles were performed. The first heating cycle was used to remove all thermal history.

Mettler Toledo 822 DSC

Film

-20 0 20 40 60 80 100

30

40

50

60

70

80 I Cycle

Flo

w R

ate

[mW

]

Temperatura [°C]

PCL film PCL CNFs 0.5% PCL CNFs 1% PCL SWNTs 1%

-20 0 20 40 60 80 100

10

20

30

40

50

60

70II Cycle

Flo

w R

ate

[mW

]

Temperatura [°C]

PCL film PCL CNFs 0.5% PCL CNFs 1% PCL SWNTs 1%

PCL + CNSs


Thermal CharacterizationThermal Characterization

-20 0 20 40 60 80 100

10

20

30

40

50

60

II Cycle

Flo

w R

ate

(mW

)

Temperatura (°C)

PCL PCL CNFs 0,5% PCL CNFs 1% PCL SWNTs 1%

DSC

The samples were heated from -25 to 100°C at a scanning rate of 10°C/min. Two heating cycles were performed. The first heating cycle was used to remove all thermal history.

Mettler Toledo 822 DSC

Membranes

-40 -20 0 20 40 60 80 10015

20

25

30

35

40

45

50

55

60 I Cycle

Flo

w R

ate

[mW

]

Temperature [°C]


PCL + CNSs


Thermal CharacterizationThermal Characterization

Xc(%)=ΔH/ΔH0 ΔH0 = 136 J/g

Polymer 41 (2000) 9073–9080

MaterialsΔHm1(J/

g)ΔHc(J/

g)ΔHm2(J/

g)Tm1(°C) Tc(°C) Tm2 (°C) Xc1(%) Xc2(%)

PCL pelletsPCL pellets 57,1± 0,9 46,0± 0,5 40,6± 0,6 58,7± 0,3 17,8 ± 0,7 56,0± 0,9 42,0± 0,529,9±

0,4

PCL filmPCL film 67 ± 2 49 ± 1 39,8 ± 0,861,61 ±

0,0122.7 ± 0,2

56,34 ± 0,08

50 ± 130.2 ±

0,6

PCL SWNTs PCL SWNTs 1% wt1% wt

60 ± 1 46 ± 1 42,6 ± 0,8 58,6 ± 0,2 32,1 ± 0,1 55,5 ± 0,244,5 ±

0,7 31,3 ±

0,6

PCL CNFs PCL CNFs 1% wt1% wt

56,8 ± 0,1 46,1 ± 0,3

39,6 ± 0,3 58,9 ± 0,2 29,88 ± 0,09

55,6 ± 0,3 41,8 ± 0,1

29,1 ± 0,2

SC_PCL SC_PCL 68,5 ± 0,9 55 ± 1 45 ± 1 57,7 ± 0,1 24,59 ± 0.01

55,6 ± 0,2 50 ± 1 33,1± 0,7

SC_PCL SC_PCL CNFs 1% wtCNFs 1% wt

57,7 ± 0,3 49,7± 0,3 43,1 ± 0,8 57,5 ± 0,3 32,6 ± 0,2 55,9 ± 0,4 42,4 ± 0,2

31,7 ± 0,6

SC_PCL SC_PCL SWNTs 1% SWNTs 1%

56,1 ± 0,2 51,0 ± 0,6

44 ± 2 57,7 ± 0,3 33,97 ± 0,09

56,1 ± 0,3 41,3 ± 0,2

32 ± 1


Thermal CharacterizationThermal CharacterizationTGA Seiko exstar 6000

Film Membranes

Td=404°C 30°C -> 1000°C, 10°C/min Nitrogen

0 200 400 600 800 1000

0.00

0.05

0.10

0.15

0.20

0.25

DT

G (g

i/gi

min

)

Temperature [°C]


0 200 400 600 800 1000

0.00

0.05

0.10

0.15

0.20

0.25

DT

G (g

i/gi

min

)

Temperature [°C]

PCL film PCL CNFs 0.5 % PCL CNFs 1% PCL SWNTs 1%


Dynamo-Mechanical Dynamo-Mechanical CharacterizationCharacterization

DMADynamic Time Sweep Test f=1Hz Strain=0.3

DMA: Dynamo-Mechanical AnalysisDMA: Dynamo-Mechanical Analysis Reometric Scientific-ARES N2Reometric Scientific-ARES N2

Film

MaterialeG'medio (108Pa)

PCL film 6,3 ± 0,2

PCL CNFs 0.5% 6,7 ± 0,2

PCL CNFs 1% 8,6 ± 0,2

PCL SWNTs 1%

8,3± 0,3


CONCLUSIONSNanocomposites made with bioresorbable PCL matrix and CNSs were processed by solvent casting technique and electrospinning.

Objective: to analyze the effects of the incorporation of CNSs and their morphology on the Thermal, Mechanical and Electrical Properties

Hydrophobic surface induced by membrane process

CNSs serve the role of a plasticizer and a crystal nucleate, which enhances the polymer segmental mobility and facilitates the crystal packing simultaneously.

Elastic modulus increases significantly with introduction of CNSs in the polymer matrix.

An introduction of CNTs in the polymer matrix affects the electrical conductivity of the nanocomposite.

These studies suggest that the combination of biodegradable polymers and carbon nanostructures, opens in fact a new perspective in the self-assembly of nanomaterials and nanodevices with tunable mechanical and electrical properties.


Acknowlodgement


Thank You!! Thank You!!

ELECTROSPUN NANOHYBRID MEMBRANES BASED ON BIORESORBABLE POLYMER AND CARBON NANOSTRUCTURES

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