Carbon based materials for Elastomer Nanocomposites

Graphene Related Materials for Elastomer Nanocomposites

Silvia Guerra, Luca Giannini, Luciano Tadiello,

Vincenzina Barbera, Maurizio Galimberti

33 collaboration projects with University

20 JDAs and more than 50 NDAs with suppliers/universities Over 100 co-operations with Premium OEMs projects on cutting

edge technology Unique motorsport know-how

Over 150 external projects on Materials, Process, Software and Electronics

~ 6,500 patents as of 2018 year end ~6.5% of High Value revenues devoted to R&D

in the last three years

R&D OPEN INNOVATION PLATFORM BUILT ON A HOLISTIC MODEL… REPLACEMENT MARKET O.E. CUSTOMERS SUPPLIERS UNIVERSITIES LEGISLATION Pirelli R&D

Tyre Insight

Tyre looks just black and round....

...but hides

significant

complexity

in

macro-components

and in materials,

down to the

nano-scale

Tyre macroscopic performance depends critically on compounds properties at lengthscales spanning 7 orders of magnitude from cm to nm



Polymers and Nanofillers are essential part of all

Rubber Compounds



Chemicals can modify the interactions between

Polymers and Fillers

 The overall performance depends on the

collective behaviour of all components

Tyre Compunds =

Nanocomposites

NanoFillers

Polymer

Curing agent

Chemicals

 Polyhedral Oligomeric Silsesquioxanes (POSS)

 Nano Oxides (Silica, Allumina)

3-D

at Nanoscale

Mechanical Properties (Low Hysteresis)

High Aspect Ratio Nanofillers

2-D

at Nanoscale

Mechanical Properties (High Modulus)  Modified Silicates

 Carbon Nano Tubes (SWNT & MWNT)  Polymeric Nanofibers

1-D

at Nanoscale

Mechanical Properties + Barrier Effect  Graphene Related Materials

 Clays (Montmorillonite)  Zirconium Phosphates

Nanomaterials as (new)fillers in Rubber Technology: Overview

20.3nm (35 layers)

=

D ₀₀₂

Debay Scherrer equation

XRD

Nanomaterials as fillers in Rubber: Carbon-based Nanomaterials

Sample Surface area (m2_/g) Number of layers HSAG 330 35 GNP 750 26 CNT 200 9 CB 80 5

Carbon Nanomaterials from a layer of sp

2

_{-bonded carbon atoms}

graphene

graphite

piled

CNT

wrapped

Grades

with different

shape anisotropy

piled

c = 0.671 nm d002= 0.354 nm

carbon black

randomly

arranged

CARBON BLACK MWCNT GRAPHENE M ul ti F unc ti onal it y PRICE/DIFFICULTY IN MAKING REINFORCEMENT ELECTRIC CONDUCTIVITY IMPERMEABILITY

[New] Materials for new Products: Multifunctionality

⇒ About 40 patents per year

regarding Graphene(graphite) and

Tyres

Graphene in Tyre Patent Trend

⇒ About 500 patents per year

regarding Graphene(graphite) and

Graphene in Elastomers - Patent highlights

Functional targets:  Mechanical reinforcement

 Electrical & Thermal Conductivity  Impermeability

Material focus:  Graphene/graphite functionalization  Polymer matrix Functionalization

Applications:  Sensors and «elctronic devices»  Products with better mechanics

 Product-related improvements – e.g. for tyres:

o Impermeability of inner-liner to keep air and garantee constant performance

o Electrical conductivity for static charge dissipation

From Materials to Performance Targets

GNPs

(Graphene nanoplatelets)

CB N326

(Carbon Black)

vs

0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 0 10 20 30 40 50 G'' 0. 7 % (f ill ed /u nf ill ed ) phr

GNPs

From Materials to Performance Targets: mechanical and electrical properties

CB N326

vs

1E-01 1E+00 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06 1E+07 0 10 20 30 40 50 σ fille d/ σ sig m a un fille d (a t 0 .1 Hz ) phr GNPs CB GNPs CB



Better mechanical and electrical properties of GNPs compared to CB N326



Mechanical percolation threshold and electrical percolation threshold firstly

achieved for GNPs

Natural rubber/GNPs composites from NR latex

GNPs

 Latex blending is acknowledged

as the best mixing procedure for obtaining the best dispersion of a filler

 Introduction of polar groups on carbon allotropes

Natural rubber/GNPs composites from NR latex

GNPs

 Latex blending is acknowledged

as the best mixing procedure for obtaining the best dispersion of a filler

 Introduction of polar groups on carbon allotropes

Oxidation

Staudenmaier’s or Hummers’ methods

Strong acids and oxidation agents

Potentially, they might be dangerous reactions

Problematic work-up: removal of acids and metal (Mn)

Synthesis of SP

 To perform functionalization reactions inspired to the principles of green chemistry,

ideally by using biosourced chemicals.

Chemistry Batterica (E. Coli) glycerol Sugar cane OH HO OH NH2 HO OH Serinol Neat Reaction O O N - 2H₂O OH OH NH₂ O O ∆ N OH HO

N OH HO

SP

+

BET = 700

m

2

_/g

Adduct of Graphene nanoplatelets and SP

GNPs

GNPs-SP adduct



Quantitative functionalization yield



Reaction does not substantially alter the bulk crystalline order of the carbon

allotrope

N OH HO NR latex GNP-SP water dispersion + sonication 30′ GNP-SP H2SO4 latex dispersion NR/GNPs-SP composite

Graphene platelets around rubber particles. Percolation at low concentration of graphitic material

Potts, J. R., Shankar, O., Du, L., & Ruoff, R. S. (2012 Macromolecules, 45(15), 6045-6055.

NR /adduct 100/10

Adduct GNP-SP

NR/GNPs -SP composites from NR latex

N

OH HO

 stacks of few layers graphene

 isolated layers

Transmission Electron Microscopy

X-Ray diffraction

Poor stacking

of graphene layers

carbon black

+

Energy: mechanical, thermal

CBN326

Adduct of SP with Carbon black

10′ sonication, analysis at time 0

10′ sonication, analysis after 3 days

5′ centrifugation at 9000 rpm/min

NR-BR / CB-SP / silica composites

IR-BR/CB-SP (or CB) composites melt blending silica + IR-BR/CB-SP(or CB)/silica composites Ingredients phr phr IR 50 50 BR 50 50 CB N326 25 20 CB/SP 0 5 Silica1165 25 25 Silane TESPT 2 2 Stearic acid 2 2 ZnO 2,5 2,5 6PPD 2 2 TBBS 1,8 1,8 Sulphur 1,5 1,5 totale 161,80 161,80

CB

CB-SP

NR-BR / CB-SP / silica composites

-Composite with CB-SP shows lower modulus at lower strain and lower G’’

modulus for a given G’ modulus:

Less filler networking

-Crossover of (G’ vs strain) curves:

Stronger polymer-filler interaction with CB-SP

CB

Graphene Related Materials for Elastomer Nanocomposites

 Graphene Related Materials for Elastomer Nanocomposites are an active field of Research and Development both in academic and in industrial environments  Target Nanocomposite functionalities in Elastomers include

 Mechanical Reinforcement

 Electrical and Thermal Conductivity

 Impermeability

 The main Technical Challenge to achieve the potential performances of Nanocomposites featuring fillers is DISPERSION and INTERFACE Control

 Functionalization of Graphene, Polymers and other fillers are envisaged

 In the frame of an open Innovation R&D Model, Pirelli developed with its Academic Partners a functionalization approach based on a partially renewably sourced

Thank you!

Silvia Guerra

Material Advanced Research Silvia.guerra@pirelli.com