Facultatea de Inginerie Electrica, Materiale electrotehnice noi, 2009-2010, master IPE, anul I...

Facultatea de Inginerie Electrica, Materiale electrotehnice noi, 2009-2010, master IPE, anul I Prof.dr.ing.Florin Ciuprina

Materiale electrotehnice noi

Nanodielectrici

Facultatea de Inginerie Electrica, Materiale electrotehnice noi, 2009-2010, master IPE, anul I

Nanodielectrici

Structura disciplineiCapitolul Conţinutul

1 Fenomene in materialele electrotehnice1.1. Conductia electrica1.2. Polarizarea electrica1.3. Magnetizarea materialelor1.4. Pierderi in materialele electrotehnice

2 Materiale conductoare noi2.1. Materiale conductoare clasice2.2. Materiale supraconductoare2.3. Conductori organici si nanotuburi de carbon2.4. Materiale pentru realizarea de memristori2.5. Aplicatii moderne ale materialelor conductoare

3 Materiale semiconductoare noi3.1. Materiale semiconductoare clasice3.2. Polimeri semiconductori3.3. Materiale semiconductoare nanostructurate3.4. Aplicatii moderne (celule solare, microprocesoare de inalta frecventa, ecrane TV, laseri)

4 Materiale dielectrice noi4.1. Evolutia materialelor dielectrice4.2. Straturi subtiri4.3. Nanodielectrici4.4. Oxizi metalici4.5. Aplicatii

5 Materiale magnetice noi5.1. Evolutia materialelor magnetice5.2. Materiale magnetice amorfe5.3. Materiale magnetice nanostructurate (nanocristaline, organice)5.4. Fire si filme subtiri din materiale magnetice5.5. Aplicatii moderne (miezuri magnetice, memorii, hard-discuri, carduri magnetice)


Nanodielectrici

1. Polymer nanocomposites as dielectrics

2. Characterisation: nanostructure, electrical & mecanical properties, thermal stability

3. Numerical modeling of nanodielectrics

4. Possible applications of polymer nanocomposites in Electrical Engineering

Nanodielectrici


Nanodielectrici

1994: Symbolic birth of Nanodielectrics:

John Lewis published the paper “Nanometric Dielectrics” in

IEEE Transactions on Dielectrics and Electrical Insulation

Nanodielectrics ≈ Polymer nanocomposites with dielectric properties: polymers (PA, PE, PP, PVC, epoxy resins, silicone rubbers)

+ nano-fillers (LS, SiO2, TiO2, Al2O3)

* 1 to 100 nm in size, * 1 to 10 wt% in content* homogeneously dispersed in the polymer matrix.

2002: First experimental data on nanometric dielectrics.

2002-2008: Articles in the field reported that nano-filler addition has the potential of improving the electrical, mechanical and thermal properties as compared to the neat polymers; polymer nanocomposites are increasingly desirable as coatings, structural and packaging materials in automobile, civil, aerospace and electrical engineering.

2006-2008: Project CEEX- PoNaDIP


Nanodielectrici

Design &

Realizing

Characterization

Modeling

Structure-Property Relationship

Steps of the research


Nanodielectrici

Design &

realizing

Research at UPB-ELMAT:

14 combinations polymer – nanofiller

Plane samples 10 X 10 cm2, thickness ≤ 1 mm

Nanofillers:1 to 100 nm in size, 1 to 10 wt% in content, and homogeneously dispersed in the polymer matrix

POLYMER

thermoplastic

thermoset

NANOFILLER

organic

inorganic


Nanodielectrici

Design &

realizing

Nanocomposites investigated

PP, PVC and LDPE with SiO2 nanoparticles of 15 nm diameter

PP, PVC and LDPE with TiO2 nanoparticles of 15 nm diameter

PP, PVC and LDPE with Al2O3 nanoparticles of 40 nm diameter

nanofillers content: 2, 5 and 10 wt%.

Manufacturing by direct mixing method

Samples for electrical tests: plaques of square shape (10 x 10 cm2) having the thickness of 0.5 mm.

Installation for nanocomposite manufacturing


Nanodielectrici





Nanodielectrici


Nanodielectrici

Nanostructure

SEM at ICECHIM

LDPE - SiO2

Characterization


Nanodielectrici

Characterization

Electrical properties

Dielectric Spectroscopy at UPB/ELMAT

real part of the permittivity ( )

loss tangent (tan δ)

dielectric spectroscopy: Novocontrol ALPHA-A Analyzer (3) in combination with an Active Sample Cell ZGS (4) and a Temperature Control System Novotherm (5)

frequency range 10-3 – 106 Hz

r


Nanodielectrici

10-4 10-3 10-2 10-1 100 101 102 103 104 105 106 107

2.0

2.1

2.2

2.3

2.4

2.5

2.6

2.7

r'

f [Hz]

PP PP + TiO

2 - 15 nm - 5%

PP + SiO2 - 15 nm - 5%

PP + Al2O

3 - 40 nm - 5%

10-4 10-3 10-2 10-1 100 101 102 103 104 105 106

10-4

10-3

10-2

10-1

tan

f [Hz]

PP PP + TiO

2 - 15 nm - 5%

PP + SiO2 - 15 nm - 5%

PP + Al2O

3 - 40 nm - 5%



Results for PP nanocomposites with Al2O3, SiO2 and TiO2 fillers

at T = 300 K


Nanodielectrici

10-4 10-3 10-2 10-1 100 101 102 103 104 105 106 107

0

5

10

15

20

25

30

35

' r

f [Hz]

PCV PCV + TiO

2 - 15 nm - 5 %

PCV + SiO2 - 15 nm - 5 %

PCV + Al2O

3 - 40 nm - 5 %

10-4 10-3 10-2 10-1 100 101 102 103 104 105 106 107

10-1

100

tan

f [Hz]

PCV PCV + TiO

2 - 15 nm - 5 %

PCV + SiO2 - 15 nm - 5 %

PCV + Al2O

3 - 40 nm - 5 %



Results for PVC nanocomposites with Al2O3, SiO2 and TiO2 fillers

at T = 300 K


Nanodielectrici

10-4 10-3 10-2 10-1 100 101 102 103 104 105 106 107 108

2.1

2.2

2.3

2.4

2.5

2.6

r'

f [Hz]

PEJD PEJD + MP PEJD + MP + SiO

2 - 15 nm - 2 %

PEJD + MP + Al2O

3 - 40 nm - 2 %

PEJD + MP + TiO2 - 15 nm - 2 %

10-4 10-3 10-2 10-1 100 101 102 103 104 105 106

10-4

10-3

10-2

10-1

100

101

tan

f [Hz]

PEJD PEJD + MP PEJD + MP + SiO

2 - 15 nm - 2 %

PEJD + MP + Al2O

3 - 40 nm - 2 %

PEJD + MP + TiO2 - 15 nm - 2 %



Results for LDPE nanocomposites with Al2O3, SiO2 and TiO2 fillers

at T = 300 K


Nanodielectrici

10-4 10-3 10-2 10-1 100 101 102 103 104 105 106 107

2.2

2.3

2.4

2.5

r'

f [Hz]

PEJD + MP PEJD + MP + Al

2O

3 - 40 nm - 2 %

PEJD + MP + Al2O

3 - 40 nm - 5 %

PEJD + MP + Al2O

3 - 40 nm - 10 %

10-4 10-3 10-2 10-1 100 101 102 103 104 105 106

10-3

10-2

10-1

tan

f [Hz]

PEJD + MP PEJD + MP + Al

2O

3 - 40 nm - 2 %

PEJD + MP + Al2O

3 - 40 nm - 5 %

PEJD + MP + Al2O

3 - 40 nm - 10 %



Results for LDPE - Al2O3 nanocomposites, for different filler concentration,

at T = 300 K


Nanodielectrici

Characterization


Absorption-Resorption Currents at UPB/ELMAT

Resistivity: Keithley 6517 Electrometer in combination Keithley 8009 Test Fixture


Nanodielectrici


Absorption-Resorption Currents at UPB/ELMAT

Characterization


Nanodielectrici


Resistivity of LDPE nanocomposites at UPB/ELMAT Characterization

MaterialRelative volume

resistivity at 10 VRelative volume

reisistivity at 500 V Unfilled LDPE 1 1LDPE with 5 wt% nano-SiO2 39.39 0.54LDPE with 5 wt% nano-Al2O3 6.08 0.19LDPE with 5 wt% nano-TiO2 4.09 0.72


Nanodielectrici

Characterization

Mechanical properties at ICECHIM

LDPE – SiO2 and LDPE – Al2O3 nanocomposites

According to ISO 527 on specimens type IB (5 specimens for each test) with 50 mm/min for tensile strength and 2 mm/min for modulus of elasticity.

0 2 4 6 8 1010

11

12

13

14

15

16

Elo

ngat

ion

at b

reak

[%]

Ten

sile

str

engt

h [M

Pa]

Nano SiO2 concentration [%]

250

300

350

400

450

500

550

0 2 4 6 8 100,8

1,2

1,6

2,0

2,4

2,8

Nano SiO2 concentration [%]

Mod

ulus

of e

last

icity

E/E

0

0 2 4 6 8 1012

13

14

15

16

17

18

Elo

ngat

ion

at b

reak

[%]

Nano Al2O

3 concentration [%]

Ten

sile

str

engt

h [M

Pa]

250

300

350

400

450

500

550

0 2 4 6 8 100,8

1,2

1,6

2,0

2,4

2,8

Modulu

s of ela

stic

ity E

/E0

Nano Al2O

3 concentration [%]


Nanodielectrici





Nanodielectrici


Nanodielectrici

Ideas multi-core model (Tanaka)

Modeling

Numerical model at UPB/ELMAT


Nanodielectrici

3D Model

nanoparticle

matrix

elementarycapacitor

Sample features:

- thickness 1 mm - diameter of the nanoparticle 40 nm - thickness if the interface 10 nm - filler content 5% - relative permittivities: nanoparticle/interface/matrix = 10/6/2.2

interface

Modeling



Nanodielectrici

Electrostatic field

div ( grad V) = 0

V – electric scalar potential – electric permittivity

Modeling



Nanodielectrici

Computational domain – in FLUX 3D

Main data of the numerical model:- dimension of the elementary cube 120 nm along each axis - nanoparticle diameter 40 nm- thickness of the interface 10 nm - concentration of nanoparticles 5% - relative electric permittivities: nanoparticle/interface/matrix = 10/6/2.2 - applied voltage 0.02 V

Modeling



Nanodielectrici

Descretization mesh - finite element method

Size of the mesh:

- 6784 nodes - 41770 volume finite elements

-- tethrahedral elements

Modeling



Nanodielectrici

Computation of the equivalent permittivity

1) Computation of the electric energy stored in the material samples:

2) Computation of the capacitance of the elementar capacitor by using two different methods:

3) Evaluation of the equivalent rel. electric permittivity r eq :

Ω

dV2

WED

2U

2WC

20

eqr AUε

2Wdε

d

AεεC eqr0

Modeling



Nanodielectrici

Numerical resultsElectric scalar potential – color map

Without nanoparticles With nanoparticles

Modeling



Nanodielectrici

Numerical resultsElectric field strength – color map

Without nanoparticles With nanoparticles

Modeling



Nanodielectrici

Parametric study

• filler content fc• diameter of the nanoparticle dn• thickness of the interface ti • relative permittivity of the polymer matrix rm • relative permittivity of the interface ri • relative permittivity of the nanofiller rn

Modeling



Nanodielectrici

Numerical resultsequivalent permittivity vs. interface permittivityre = f(ri)

fc = 5% dn = 40 nmti = 10 nmrm = 2.2rn = 10ri = 3; 4; 5; 6; 7; 8

Modeling

2

2.05

2.1

2.15

2.2

2.25

2.3

2.35

2.4

2.45

2.5

3 4 5 6 7 8

epsr interface

epsr

eq

uiv

alen

t

.



Nanodielectrici

Numerical resultsequivalent permittivity vs. the thickness of the interface layer

re = f(ti)

fc = 5% dn = 40 nmti = 5; 10; 15; 20 nmvi = 0rm = 2.2rn = 10ri = 4

Modeling2

2.05

2.1

2.15

2.2

2.25

2.3

2.35

2.4

2.45

2.5

5 10 15 20

thickness of the interface [nm]

epsr

equ

ival

ent



Nanodielectrici

Numerical resultsequivalent permittivity vs. the diameter ofthe nanoparticle

re = f(dn)

fc = 5% dn = 10; 20; 30; 40; 50 nmti = 10 nmrm = 2.2rn = 10ri = 4

Modeling2

2.05

2.1

2.15

2.2

2.25

2.3

2.35

2.4

2.45

2.5

10 20 30 40 50

diameter of the nanoparticle [nm]

epsr

equ

ival

ent



Nanodielectrici

Numerical resultsequivalent permittivity vs. nanoparticle permittivity

re = f(rn)

fc = 5% dn = 40 nmti = 10 nmrm = 2.2rn = 4; 10ri = 2.2

Modeling

2

2.1

2.2

2.3

2.4

2.5

4 6 8 10

epsr nanoparticle

epsr

eq

uiv

alen

t



Nanodielectrici

Particle agglomeration

Modeling



Nanodielectrici

Particle agglomeration + isolated particles

Modeling



Nanodielectrici





Nanodielectrici


Nanodielectrici

Nanocomposite applications in Electrical engineering at ETN-EE Manufacturing and testing of coil holders

Selected materials: LDPE + Al2O3 and LDPE + SiO2 with 2% filler content.

Coil holders made from selected nanocomposites have better behaviour as compared with those from the neat polymer (dielectric strength, mecanical properties and, obviously, flame retardancy)

Facultatea de Inginerie Electrica, Materiale electrotehnice noi, 2009-2010, master IPE, anul I...

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