LOW ENVIRONMENTAL IMPACT PLASTICS

Prof.Marco-Aurelio De Paoli

Universidade Estadual de Campinas (UNICAMP) - Brasil

2009

Post-doctoral work at MPI für Strahlenchemie, RFA, 1975 – 1977.Alexander von Humboldt Stiftung

Introduction

Aims of our research:

• Develop thermoplastic composites with adequate mechanical properties, reduced environmental impact and good cost/benefit ratio; use of renewable resources.

•To replace short glass fibers in reinforced thermoplastics processed by injection molding; weight and environmental impact reduction.

“They (automobiles) will be

lighter and much of them will

be built of plastics developed

from farm products”.

Henry FordHenry Ford, from an article written by James Schweinehart published in The Detroit News of July, 30rd, 1942.

Introduction

Car parts made with natural fibers composite

Vegetal fibers can be used in substitution to fiber glass due to the following advantagesadvantages:

•Produced from renewable resources.

•Less abrasive to the processing equipments.

•Lower density, producing lighter composites,

•Better thermal and acoustic insulation,

•Better surface finish in injection molded parts,

Introduction

Vegetal fibers also present some challengeschallenges.

•Vegetal fibers decompose thermally above 220 oC.

•Like with fiberglass, composites cannot be mechanically recycled. They

can be recycled only by pyrolysis (however, with carbon credits),

•Vegetal fibers reinforced thermoplastics show higher flammability, thus,

the use of a flame retardant is necessary.

•Achieve a competitive cost in relation to synthetic fibers.

Introduction

dens.

Why use Curauá fibers and not the market available vegetal fibers ?

Specific density, stress, E and b for same reinforcing fibers*

1,0-1,3164-17128601,4Carbon

2,4-2,645-482140-22401,4Aramid

1,134,418002,5glass (S)**

1,028800-14002,5glass (E)*

1,3-1,76,3-14,7340-4161,5Sisal

2,4-2,541-85270-6251,5Ramie

1,8-2,118,4230-7901,5Linho

1,2-1,420,4302-5951,3Jute

4,7-5,03,4-7,9191-3981,5-1,6cotton

b / % cm3/g

E / GPa cm3/g

/ MPa /g.cm-3

Density g/cm3

fiber

* Electric insulation, ** militar applications.*- from: A. K. Bledzki; J. Gassan. Composites reinforced with cellulose based fibres. Progres in Polymer Science 24 (1999) 221-274.

stress., E e b specific for Curauá fibers

3 ± 136 ± 10 636-1000FC

b / (% cm3/g)E / (GPa cm3/g)força máx / (MPa /g.cm-3)Fiber

1,10

Introduction

HDPE, Braskem, MFI = 7 g/10 min.

PP, Braskem, MFI = 10 g/10 min.

Curauá fibers, dryed and milled in a three knives

rotary mill, Rone.

Materials used

side feederMain feeder degasing

Co-rotating interpenetrating twin-screw extruder, Werner-

Pfleiderer ZSK-26, L = 1056, D = 24 mm, L/D = 44 (Fapesp

2004/15084-6), SRS 250 – 500 rpm, side feeder 200 – 465 rpm.

Injection molding Arburg All Rounder M-250

Processing equipment

Processing equipment

Experimental: processing parameters

HDPE matrix

SRS* (rpm) Mass temperature(°C)**

Pressure(bar)

Torque(%)

Output(kg/h)

SME***(Wh/kg)

250/200 136-160 4-19 33-40 1.9 1.1

300/250 143-164 4-22 34-38 2.2 1.1

350/300 140-168 6-16 30-42 2.4 1.2

400/350 151-172 5-23 28-41 3.1 1.0

500/450 145-178 9-14 32-37 3.5 1.1

PP matrix

250/215 171-195 7-16 31-41 2.5 0,8

300/265 177-195 8-16 30-37 2.6 0,9

350/315 177-199 7-16 29-34 2.6 1,0

400/365 175-204 10-16 27-34 2.9 1,0

500/465 178-202 10-12 29-37 3.6 1,0

*Main screws/side feeder screws** polymer temperature near the dye*** Specific Mechanical Energy

Above 350 rpm, aspect ratio decreases

HDPE matrix: effect of SR on fiber geometrical parameters

Screw rotation (rpm) 250 300 350 400 500ARn 18 16 15 12 7ARw 35 34 28 20 10

ARw/ARn 2 2 2 2 1

0 20 40 60 80 100 120

0.2

0.4

0.6

0.8

1.0

CF

D

Aspect Ratio

Legend: pristine fiber () and composites processed at () 250, () 300, () 350 (), 400 and () 500 rpm

6 μm

HDPE-Fibrillation effect: MEV

50 μm

100 μm

Matriz HDPE: mechanical properties

The yield stress and Young’s Modulus show a decreasing tendency, in accordance with the

decrease in the fiber aspect ratio.

The elongation at break increases due to the decline in the reinforcement effect.

14% tensile 7% flexural

26% tensileFlexural n.v.

50%

Formulaçãoem wt %

máx./ (MPa.g/cm3)máx. (MPa)

E (MPa)/ (MPa.g/cm3)

E (MPa)

(%)/ (%)

HDPE 17.8 ± 0.1 1358 ± 152 < 100HDPE/20%FC 28.4 ± 0.2

28.1 ± 0.22501 ± 4472471 ± 447

3.7 ± 0.13.7 ± 0.1

HDPE/20%FC/

2%PEAM

30.7 ± 0.330.3 ± 0.3

2763 ± 2942730 ± 294

3.2 ± 0.53.2 ± 0.5

HDPE/30%FV* 42 - 5152 - 63

3952 - 50804900 - 6300

1.2 - 2.01.5 - 2.5

Tensile mechanical tests - ASTM D-638

*PE 30 % GF – Polyethylene 30 % Glass fiber ®, Omnexus, United States, 2007.

dCFC = 0.988 ± 0.04 g/ cm3 (15,7 % em volume)

dCFV = 1.2 - 1.28 g/ cm3 ( 1,27 g/cm3 com 15 % em volume)

HDPE

Flexural mechanical tests ASTM D-790

Formulaçãoem wt %

máx./ (MPa.g/cm3)máx. (MPa)

E (MPa)/ (MPa.g/cm3)

E (MPa)HDPE 20.9 ± 0.5 888 ± 43

HDPE/20%FC 37.5 ± 0.337.1 ± 0.3

1609 ± 981590 ± 98

HDPE/20%FC/

2%PEAM

41.4 ± 0.340.9 ± 0.3

1983 ± 1291959 ± 129

HDPE/30%FV*

42 - 5152 - 63

3952 - 45164900 - 5600

*PE 30 % GF – Polyethylene 30 % Glass fiber ®, Omnexus, United States, 2007

dCFC = 0.988 ± 0.04 g/ cm3 (15,7 % em volume)

dCFV = 1.2 - 1.28 g/ cm3 ( 1,27 g/cm3 com 15 % em volume)

HDPE

Impact resistence ASTM D-256

Formulaçãoem wt %

Resistência ao Impacto

Izod (J.g/cm3)(J/m)

Resistencia ao Impacto

Charpy (kJ/m2)

HDPE 82.3 ± 6.4 3.5 ± 0.1HDPE/20%FC 62.8 ± 2.9

62.0 ± 2.93.5 ± 0.4

HDPE/20%FC/

2%PEAM

66.0 ± 3.965.2 ± 3.9

3.4 ± 0.2

HDPE/30%FV*

48 - 6460-80

-

*PE 30 % GF – Polyethylene 30 % Glass fiber ®, Omnexus, United States, 2007

dCFC = 0.988 ± 0.04 g/ cm3 (15,7 % em volume)

dCFV = 1.2 - 1.28 g/ cm3 ( 1,27 g/cm3 com 15 % em volume)

HDPE

Changes in aspect ratio with screw rotation

PP matrix: effect of SR on fiber geometrical parameters

Legend: pristine fiber () and composites processed at () 250, () 300, () 350 (), 400 and () 500 rpm

0 20 40 60 80 100 1200.0

0.2

0.4

0.6

0.8

1.0

CD

F

Aspect ratio

PP-Fibrillation effect: MEV

PP matrix: mechanical properties

Tensile yield stress and Young Modulus show a decreasing tendency, in accordance with the variation in the fiber aspect ratio.

The elongation at break increases due to the decline in the reinforcement effect.

12.5% tensile flexural n.v.

5% tensileflexural n.v.

32%

Formulaçãoem wt %

σmáx./d (MPa/g cm -3)

σ máx. (MPa)

E (MPa)/d (GPa.g/cm3)

E (MPa)

(%)/d e (%)

PP 27,2 ± 0,5 1736 ± 112 > 300PP/20%FC 32,3 ± 0,2

31,4 ± 0,52870 ± 2542790 ± 254

1,9 ± 0,21,8 ± 0,2

PP/20%FC/2%PPAM 39 ± 0,238 ± 0,2

3393 ± 3573298 ± 357

2,2 ± 0,32,1 ± 0,3

PP/20%FV* 4345

38104000**

4,85

Mechanical tensile tests, ASTM D-638

* PP com 20 wt% de FV – Petrotene PH304, Petropol Polímeros ** Polypropylene/ 20 % Glass fibre ®, Omnexus, United States, 2007

dCFC = 0, 972 ± 0, 010 g/ cm3 (15 % em volume)

dCFV = 1,05 g/ cm3 (1,14 g/cm3 com 8 % em volume)

PP

Flexural mechanical tests, ASTM D-790

Formulaçãoem wt %

máx./ (MPa/g/cm3)máx. (MPa)

E (MPa)/ (MPa/g/cm3)

E (MPa)PP 37,1 ± 1,4 1046 ± 59

PP/20%FC 51 ± 150 ± 1

2187 ± 1002126 ± 100

PP/20%FC/2%PPAM

58 ± 156 ± 1

1913 ± 2141859 ± 214

PP/20%FV* 7680

30003000

* PP com 20 wt% de FV – Petrotene PH304, Petropol Polímeros

dCFC = 0, 972 ± 0, 010 g/ cm3 (15 % em volume)

dCFV = 1,05 g/ cm3 (1,14 g/cm3 com 8 % em volume)

PP

Impact resistence tests, ASTM D-256

Formulaçãoem wt %

Resistência ao Impacto

Izod (J/g/cm3)(J/m)

Resistência ao Impacto

Charpy (kJ/m2)

PP 17,3 ± 4,43 1,6 ± 0,2PP/20%FC 28 ± 9

27 ± 93,3 ± 0,6

PP/20%FC/2%PPAM

29 ± 328 ± 3

2,6± 0,3

PP/20%FV* 5255

-

dCFC = 0, 972 ± 0, 010 g/ cm3 (15 % em volume)

dCFV = 1,05 g/ cm3 (1,14 g/cm3 com 8 % em volume)

* PP com 20 wt% de FV – Petrotene PH304, Petropol Polímeros

PP

Developed under contract with Sabic Innovative Plastics

Car parts made with Nylon-6/curauá fibers composite

Developed under contract with Sabic Innovative Plastics

Car parts made with Nylon-6/curauá fibers composite

• Aspect ratio of the fibers in the injection molded samples is affected by the processing conditions in the extruder.

• For both polymers, the mechanical properties are affected by the fiber aspect ratio variation.

• HDPE is more affected than PP by the processing conditions.

• Final mechanical properties depend on the correct choice of processing conditions.

CONCLUSIONS

Research group

• MSc, Bárbara Mano, MSc, Bárbara Mano, • MSc, Joyce Araújo, MSc, Joyce Araújo, • Vanessa S de OliveiraVanessa S de Oliveira• Prof. Dr. Márcia AS SpinacéProf. Dr. Márcia AS Spinacé• Léa Garcia JaneiroLéa Garcia Janeiro• Filippe BernardinoFilippe Bernardino• Thais GrossiThais Grossi• MSc, Paulo Santos (SABIC)MSc, Paulo Santos (SABIC)• Karen Fermoselli (SABIC/Unicamp)Karen Fermoselli (SABIC/Unicamp)• Prof. Dr. Walter R Waldman (UENF)Prof. Dr. Walter R Waldman (UENF)

Procs.04/15084-6, 06/58342-0, 06/58343-7, 08/06503-6 e 08/06506-8.

ACKNOWLEDGEMENTS