CHANCES AND THREATS FOR NATURAL RUBBER FOR USE IN LOW ROLLING RESISTANCE TYRES

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USE IN LOW ROLLING RESISTANCE TYRES Title: to modify

1 Elastomer Technology and Engineering, Enschede, the Netherlands CHANCES AND THREATS FOR NATURAL RUBBER FOR USE IN LOW ROLLING RESISTANCE TYRES Title: to modify choose 'View' then Malaysian Rubber Board 'Heater and footer' 1

2 Performance of Silica based NR Tires NR Truck Tires Wet traction Treadwear Rolling resistance Carbon Black phr phr Wolff, Rubber Chem. Technol., 69 (1996) 2

3 Tire Performance & Silica Technology Polymer/Rubber type Silica Coupling agent Mixing technology 3

4 Silica-Silane-Rubber Coupling Silanization: silica and silane reaction Silanization: Primary & secondary reaction Silane-rubber coupling H H 3 C Vulcanization 4

5 Silica Reinforced Rubber Network Silica-rubber coupling (silica-coupling agent-rubber bond) x Rubber rubber bonds (sulphur crosslinks) Silica Rubber chain Coupling agent: TESPT 5

6 NR Research topics at UT/ETE General aim Improving the reactivity of natural rubber (NR) towards silica in order to make NR / HD silica more efficient for reinforcement of tire-treads Focus of the investigations Optimization of the mixing process of NR-silica compounds Influence of proteins on silica reinforcement in NR Modification of NR to improve tire properties Different types of coupling agents more suited for NR 6

7 Research questions Proteins versus silanes: (how) do they interfere? Rubber filler: how do they interact in a silica-filled NR compound? What is the influence of proteins on silica reinforcement in NR? 7

H CH 2 H 2 C n cis -1,4 polyisoprene Advantages Synthetic Rubber 52 % Renewable resource Converts solar energy to raw material World

8 Natural Rubber A strategic green material Outstanding Properties Natural Rubber 48% Low hysteresis High tensile strength High elasticity Good resilience Low heat build up Resistance to abrasion Resistance to crack growth Flexibility at low temperature CH 3 C C H CH 2 H 2 C n cis -1,4 polyisoprene Advantages Synthetic Rubber 52 % Renewable resource Converts solar energy to raw material World rubber consumption, 2008 Effective CO 2 sequester Low energy input Source : Hevea Brasiliensis Low fertilizer demand Valuable source of timber 8

Network of Linear NR Chain (associated with proteins and phospholipids) CH 3 H 2 C CH 2 CH 3 CH 3 Mono- or di- phosphate group phospholipids C ω-terminal CH 3 ω -terminal C H (trans) 2 C C H CH 3 H 2

9 Network of Linear NR Chain (associated with proteins and phospholipids) CH 3 H 2 C CH 2 CH 3 CH 3 Mono- or di- phosphate group phospholipids C ω-terminal CH 3 ω -terminal C H (trans) 2 C C H CH 3 H 2 C trans 2 CH 2 (cis)n C C H H 2 C cis n C C H α -terminal CH 2 CH 2 OH α-terminal H-bond or Mg 2+ 2 trans-1,4 isoprene units cis-1,4 isoprene units phospholipids Mono- or diphosphate group proteins Tanaka et al., Rubber Chem. Technol, 67(1993),74(2001), 81(2008), 82(2009) Sakdapipanich et al., Kautsch. Gummi Kunst. 3/2005, 10/2008 9

10 Proteins in Natural Rubber Hevea latex : 30-45% rubber hydrocarbon 3-5% non-rubber constituents water Removal of non-rubber constituents: Enzymatic deproteinisation - protein Transesterification - phospolipids Saponification - protein + phospolipids Protein distribution Rubber phase 25% Rubber N 2 content C-serum Bottom fraction (B-serum) 43% 32% Natural Rubber % Deproteinized % NR Skim rubber % Yeang et al., Methods 27 (2002) 10

11 Experimental: Compound Formulation Ingredients phr Natural Rubber, NR (varied) 100* Silica, Ultrasil Silane, TESPT 5 Zinc Oxide 2.5 Stearic acid 1 Santoflex TMQ 2 TDAE oil 8 DPG 2 Sulphur 1.4 CBS 1.7 * Adjustment in Skim rubber formulation : 112 phr Rubber types Deproteinized NR (DPNR) Nitrogen content ( wt. % ) 1 st stage mixing in Brabender 350S Mixing conditions: Mixing time: 14 minutes Rotor speed: 60 rpm Fill factor: 0.7 Dump temp. varied from 110 C till 170 C 2 nd stage mixing: two-roll mill Protein content ( wt. % )** NR (SMR 20) Skim Rubber* **Conversion factor:

12 Processability: Mooney viscosity 12

13 Rheological Properties Torque Flocculation Time 13

14 Rheological Properties at 150 o C 14

15 Filler-Filler Interaction: Payne Effect Shear modulus G* Silica Silica + silane Log strain 15

16 Payne Effect versus Temperature DPNR-no silane NR-no silane 16

17 Payne Effect versus Protein Content 0,5 G' at 0.56% - G' at 100%, MPa 0,4 0,3 0,2 0,1 Silane No silane 0 DPNR NR Skim Rubber 0, Protein content in NR, wt % 17

18 Dispersion: Wolff Filler Structure Parameter DPNR-no silane Torque Temperature DPNR D max D o max D min 1= α o f D min m f m p NR NR-no silane SkimR Wolff α f SkimRno silane Wolff, Kautsch. Gummi Kunst. 34, (1981) 18

19 Filler-Polymer Interaction: Bound Rubber Content Silica compound NO SILANE Chem. BRC (%) Phys. BRC (%) Chemical BRC, % Physical BRC, % NR 0 57 DPNR 0 45 Skim R Dump Temperature, C Dump Temperature, C 19

20 TEM Network Visualization (without silane) NR-silica-no silane DPNR-silica-no silane NR Network DPNR Network Strong interface Weak interface Formation of vacuoles Silica Silica Vacuole Vacuole 20

21 TEM Network Visualization (with silane) NR-silica-silane DPNR-silica-silane NR Network DPNR Network Silica Silica No vacuoles Strong rubber to filler bonding 21

22 AFM of silica vulcanizates NR - silane DPNR - silane NR - no silane DPNR - no silane 1 x1μm 22

23 Tensile Properties DPNRno silane SkimRno silane NR-no silane 23

24 Reinforcing Index 24

25 Dynamic Properties (Tan delta at 60 C) 0.2 Tan δ at 60 C Dump Temperature, C 25

26 Summary Proteins coupling agent: antagonistic effect in silica reinforcement of NR Silane: enhances the properties of compound and vulcanizate in the presence and absence of proteins Effect of proteins: most pronounced when no silane is used High amounts of proteins: disrupt the silica-silica network and improve silica dispersion.reduce the temperature sensitivity of the material but do not improve final properties due to missing filler-polymer coupling 26

27 27

28 Purification of NR Removal of non-rubber constituents from NR Enzymatic deproteinisation protein Transesterification - phospolipids Saponification - protein + phospolipids Tanaka et al., Rubber Chem. Technol, 82 (2009) 28

29 Modification of NR H 3 C CH 2 C NR CH H 2 C H 3 C C O CH Epoxidation CH 2 H 2 C Modifications Epoxidized Natural Rubber (ENR) grafting Graft copolymerization O O O O H 3 C C C O CH 3 H 2 C C CH CH 2 H 2 C Maleated Natural Rubber (MNR) H 3 C CH 2 CH CH 2 CH H 2 C NR - methyl methacrylate graft copolymer (NR-g-PMMA) 29

30 Summary of Properties 30

Use of nano zinc oxide in natural rubber

Use of nano zinc oxide in natural rubber VÉÇàxÇàá 4.1 Introduction 4.2 Experimental 4.3 Results and discussion 4.4 Conclusions 4.5 References 4.1 Introduction Natural rubber (NR) is a high molecular weight polymer of isoprene (2-methyl-1,3-butadiene).