Cellulose Reinforced High Density Polyethylene

Presented by

Velu Palaniyandi

M.S. Thesis DefenseAdvisors:

Dr.John SimonsenDr.Ralph Busch

Contents

Background IntroductionObjectivesMaterials and MethodsResultsConclusionsAcknowledgements

Source : Reinforced Plastics, Feb 2004

Background

Natural Fiber Reinforced Composites (NFRP) applications in Car Interiors

Some More ApplicationsHeat deflection temperatureGas barrier / permeability

Packaging materialsElectrical conductivity

Electronics ,Housing appliances Flame retardancy

Source :Plastic technology ,Feb 2004

0

20

40

60

80

100

120

140

160

E-glassHemp

Flax

Jute

Sisal

CoirCotton

cellulose nanocrysta

lDouglas F

ir

Ponderosa Pine

Stiff

ness

/Spe

cifi S

tiffn

ess(G

pa) Stiffness

Specific Stiffness

Property Comparison Among the Commonly Used Reinforced Fibers

IntroductionWhy cellulose-reinforced thermoplastics?

Property enhancement at lower density and cost than synthetic fiber materials (glass, carbon)Non-abrasive and easily recyclable compared to inorganic fillersHigh strength to weight ratioSound abatement capabilityLow energy for processing

(6500 BTU/lb of kenaf ; 23,500BTU/lb of glass fiber)

Matrix

σ 1

strain,ε

Fiber

εmεf =εc

Compositeσ1

σ1

decreases ε, increases E

Role of fiber and Matrix in FRP

Fiber

High stiffness

Brittle

Matrix

Medium for stress transfer

Binds the fiber togetherStress-Strain curve

Fiber Reinforced Composite - Issues

Fiber dispersionDispersing agent

Interfacial adhesionCompatabilizer or coupling agentsSurface modification of fibers

Effect of filler on the crystallization behavior of polymer

Compatabilizer – Function and Mechanism

CelluloseOH

OH

OH

OH

OH

Matrix

ObjectivesTo prepare nanocrystalline cellulose with high aspect ratioTo investigate the material properties of nanocrystalline cellulose (NCC) filled high density polyethylene (HDPE)To use microcrystalline cellulose (MCC) as a model filler for NCCTo disperse MCC using a coupling agent systemTo study the non-isothermal crystallization kinetics of the filled composites

MaterialsMatrix: High Density Polyethylene Filler

Cellulose nanocrystal from CottonMicrocrystalline cellulose (FMC Corp, NJ)

Coupling agent:MAPE (Optipak 210)

Developed by Kaichang Li’s labAKD (Aquapel 364)PMDI (Rubinate 1840)

Experimental MethodsAmorphous region

Individual cellulose microfibrils

Crystalline regions

Acid hydrolysis

Individual crystallites

Schematic of acid hydrolysis of cellulose

Brabender PlasticorderMelt mixing HDPE and NCC/MCC at 180 oC for 10 minMAPE (0.4 wt%) and AKD-PMDI (1.0 wt%) was added during mixing

Carver Hot pressCompression molding at 185 oC at 348.5 kPa for 10 min

Composite Preparation Method

Mechanical testing –Sintech 1G, Universal testing machine

Flexural strength (MOR) and Flexural modulus (MOE) were measured according to ASTM D 790-02

Thermal AnalysisDifferential Scanning Calorimetry, TA Instruments DSC 2920

-Temperature range – 20-200oC- Heating/cooling rate – 5, 10, 12.5, 15oC/min

Thermo gravimetric analysis , TA Instruments, Q500

- Temperature range – 40-600oC- Heating rate –10oC/min

Composite Characterization Techniques

Results – TEM Characterization/Mechanical Testing

Transmission Electron Micrograph From Cellulose Nanocrystal Suspension Negatively Stained With

Ammonium Molybdate

Mag -100,000X

Diameter – 4nm

Length – 120 – 160 nm

Aspect ratio – 30-40

LAspect ratio =L/d

d

Mag -100,000X

Flexural Strength (MOR)

20

22

24

26

28

30

32

34

-5 0 5 10 15 20 25

Wt % MCC/NCC content

MOR

(MPa

)

MCC-HDPE20

22

24

26

28

30

32

34

36

-5 0 5 10 15 20 25

Wt % MCC/NCC content

MOR

(MPa

)

MCC-HDPE

MCC_MAPE_HDPE

20

22

24

26

28

30

32

34

36

38

-5 0 5 10 15 20 25

Wt % MCC/NCC content

MO

R (M

Pa)

MCC-HDPE

MCC-AKD-PMDI-HDPE5%NCC-HDPE

0.600

0.700

0.800

0.900

1.000

1.100

1.200

1.300

1.400

1.500

1.600

-5 0 5 10 15 20 25

Wt % MCC/NCC CONTENT

MOE

(GPa

)

MCC-HDPEMCC-MAPE-HDPEMCC-AKD-PMDI-HDPE5%NCC-HDPE

Flexural Stiffness

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 5 10 15 20 25Wt % of MCC

Asp

ect

rati

o (

L/D

)Aspect ratio with No MAPE

Aspect ratio with MAPE

Low aspect ratio due to agglomeration

Light Microscopy Image of the Cross Section Perpendicular to the Length

of the Samples

Mag-20x

Mag-10x

Agglomerated cellulose fibers in

5%NCC-HDPE composite

Light Microscopy Image of the Cross Section Perpendicular to the Length

of the Samples

Mag-20x

Dispersed cellulose fibers in 5%MCC-AKD—PMDI-HDPE sample

THERMAL ANALYSIS Differential Scanning Calorimetry/

Thermal Gravimetric Analysis

Polymer Crystallization

Isothermal Crystallization Constant temperature processAvrami, Ozawa,Kissinger

Non- Isothermal crystallizationConstant cooling rate processSimulates real processing conditions Modified Avrami, Kissinger

Kissinger Method –Activation Energy (Ea)

d (ln ϕ/Tp2) /d(1/Tp) = -∆E/R

ϕ– Cooling rate (ok/min)Tp – Crystallization peak temperature (k)∆E – Activation energy (kJ/mole)R- Universal gas constant (= 8.314 j/mol k)

dQ/dT

Crystallization

Heating

Cooling

End

othe

rmic

Exo

ther

mic

High temp

High temp

Low temp

Tp

Matrix Crystallinity= ∆Hc/∆Hoc

Low temp

Melting

RESULTS

Thermal Analysis

Crystallization Peak TemperatureC r y s t a l l i z a t i o n p e ak t e mp e r a t u r e a t 1 0 pe r m i n

3 8 7

3 8 7 . 5

3 8 8

3 8 8 . 5

3 8 9

3 8 9 . 5

3 9 0

3 9 0 . 5

0 5 10 15 20 25

%M CC

M C C - H D P E

C r y s t a l l i z a t i o n p e a k t e m p e r a t u r e a t 1 0 p e r m i n

3 8 6

3 8 6 . 5

3 8 7

3 8 7 . 5

3 8 8

3 8 8 . 5

3 8 9

3 8 9 . 5

3 9 0

3 9 0 . 5

3 9 1

0 5 10 15 20 25

%M C C

M C C - HD P E

M C C - M A P E - H DP E

C r y s t a l l i z a t i o n p e a k t e mp e r a t u r e a t 1 0 p e r mi n

3 8 5

3 8 6

3 8 7

3 8 8

3 8 9

3 9 0

3 9 1

0 5 10 15 20 25

%M CC

M C C - H D P E

A K D - P M D I - H D P E

Percent Matrix Crystallinity

40

45

50

55

60

65

70

75

-5 0 5 10 15 20 25

Wt % MCC

Perc

ent c

ryst

allin

ity(%

)

MCC_HDPE

40

45

50

55

60

65

70

75

80

-5 0 5 10 15 20 25

Wt % MCC

Per

cent

Cry

stal

linity

(%)

MCC_HDPE

MCC-MAPE-HDPE

40

45

50

55

60

65

70

75

80

85

-5 0 5 10 15 20 25

Wt % MCC

Perc

ent C

ryst

allin

ity (%

)

MCC_HDPE

MCC-AKD-PMDI-HDPE

Activation Energy

MCC-HDP E

70

90

110

130

150

170

190

-5 0 5 10 15 20 25

% MCC content

Act

ivat

ion

Ener

gy (k

j/mol

e) MCC-HDPE

70

90

110

130

150

170

190

-5 0 5 10 15 20 25

% MCC content

Act

ivat

ion

Ener

gy (k

j/mol

e)

MCC-HDPE

MCC-MAPE-HDPE

70

90

110

130

150

170

190

-5 0 5 10 15 20 25

% MCC content

Act

ivat

ion

Ener

gy (k

j/mol

e)

MCC-HDPE

MCC-AKD-PMDI-HDPE

1.00

1.10

1.20

1.30

1.40

1.50

1.60

-5 0 5 10 15 20 25

Wt %MCC

Avr

ami e

xpon

ent,n

MCC-MAPE-HDPE

AKD-PMDI-HDPE

Avrami Exponent

0

2

4

6

8

10

12

14

16

0 50 100 150 200 250 300 350 400 450 500 550 600 650

Te mpe rature (oC)

Wei

ght l

oss

rate

(%/m

in)

20%MCC-HDPE

20%MCC-AKD-PMDI-HDPE

Derivative Thermogravimetric (DTG) Curves

0

2

4

6

8

10

12

20 70 120 170 220 270 320 370 420 470 520 570

Temp

Wei

ght l

oss

rate

(%/m

in)

Pure Cellulose

Cellulose nanocrystal Sulfate groups

decrease onset degradation temperature

Ea=113.53kj/mole

Ea=153.1kj/mole

(oC)

Derivative Thermogravimetric (DTG) Curves

ConclusionsCoupling agents increase strength.Fillers alter nucleation behavior PMDI-AKD increases crystallinity.PMDI-AKD changes the activation energy and peak crystallization temperatureDegradation behavior of the composite is not altered in the presence of compatabilizer.Grafted sulfate groups decreases the activation energy and onset degradation temperatureThe concept of compatabilizer systems can be extended to nanocomposites

AcknowledgementsThis project was funded by a grant from the USDA National Research Initiative Competitive Grants ProgramAdvisors

Dr.John SimonsenDr.Ralph Busch

Committee membersDr.Joe KarchesyDr.Sundar V.AtreDr.Jeffrey K.Stone

Thanks to my colleagues in my group and to folks in WSE dept