**3. Carbon black reinforcement of DPNR**

The reinforcing of DPNR by carbon black has been studied in the past [46, 47]. For mixing carbon black and natural rubber, a high reinforcement can be obtained with good dispersion of filler as there is strong physical interaction between the carbon black and the rubber. DPNR-CV is a grade of viscosity stabilized at between 60 and 70 Mooney units. The typical vulcanizate properties of DPNR-CV in comparable to SMR CV is shown in **Table 6** [46]. DPNR-CV gives lower water absorption and compression stress relaxation. **Table 7** shows the physical properties of DPNR filled with carbon black at 50 phr loading and cure using EV system [46]. Similar results are observed where DPNR gives lower water absorption and compression stress relaxation.

The recent evaluation of DPNR (Pureprena) shows that its physical properties are comparable to SMR CV and SMR 10 (**Table 8**). Comparison of DPNR with synthetic polyisoprene (IR) is reported where DPNR shows similar tensile properties and low water absorption to IR (**Table 9**) [48]. The rubber compound using DPNR with total nitrogen content adjusted in the range of 0.12–0.3% by weight exhibits an improved low hysteresis loss property, excellent abrasion resistance, and remarkably excellent tear resistance which is advantageous to be used for tire tread [49].


*\*Rubber formulation: rubber 100, N330 35, ZnO 5, StA 2, TBBS 0.7, S 2.25. Cheang KT, Rais AR, Basir KB. Deproteinised Natural Rubber (DPNR), Malaysian Rubber Board (MRB) Monograph No. 10, C&D Trading, Kuala Lumpur, (2003).*

### **Table 6.**

*Typical vulcanizate properties of DPNR-CV.*


*\*Rubber formulation: rubber 100, N774 50, ZnO 5, ZEH 2, Permanex TQ 2, MOR 1.44, TBTD 0.6, S 0.6, cured at 150°C for 20 min. Cheang KT, Rais AR, Basir KB. Deproteinised Natural Rubber (DPNR), Malaysian Rubber Board (MRB) Monograph No. 10, C&D Trading, Kuala Lumpur, (2003).*

**51**

*Silica-Reinforced Deproteinized Natural Rubber DOI: http://dx.doi.org/10.5772/intechopen.85678*

*for 6 min.*

**Table 8.**

*Physical properties of DPNR (Pureprena).*

**4. Silica reinforcement of DPNR**

*Comparison of physical properties of DPNR with IR.*

Volume swell in water: 7 day/23°C, %

3 day/100°C, %

*# Pureprena. ##SK1-3.*

**Table 9.**

passenger car tires has been investigated [2, 7, 24, 52–54].

The reinforcement of rubber by silica is different from the reinforcement by carbon black. The use of conventional silica has been limited to a white filler for colored rubber compounds [2] such as shoe soles, until the introduction of bifunctional silanes as coupling agents back in the 1970s [50]. In 1992, Michelin patented the silica-filled rubber compound for the production of all-season high-performance tires [1], which provide an excellent compromise of low rolling resistance, good traction on wet and snow-covered roads, as well as noise reduction. The rubber compound is a blend of high-vinyl solution SBR and high-cis BR filled with highly dispersible silica [51] at a loading of 80 phr and an organosilane coupling agent. Since then, a lot of work on reinforcement of silica in SBR-based

*\*Rubber formulation: rubber 100, N774 20, ZnO 4, ZEH 2, TMQ 2, accelerator 1.44, accelerator 2 0.7, S 0.7.*

*Abd Rahim R, Zaeimoedin TZ, Muhamad AK, Sarkawi SS. New Process Deproteinised Natural Rubber (Pureprena): Raw Rubber, Processability and Basic Physical Properties, Malaysian J. Analytical Sciences. 2016; 20(5):1145-1152.*

**Properties DPNR SMR CV SMR L SMR10** Tensile strength, MPa 28 26 27 27 Elongation at break, % 590 560 570 570 M100, MPa 2.4 2.4 2.4 2.5 M300, MPa 12.0 12.3 12.4 12.3 Hardness, IRHD 71 68 69 70 Resilience, % 55 57 58 55 Abrasion resistance index (ARI), % 109 106 110 114 *\*Rubber formulation: rubber 100, N234 60, ZnO 3, StA 2, 6PPD 2, Wax 1, TDAE 8, CBS 1.5, S 1.5, cured at 150°C* 

**Properties DPNR# IR## SMR CV** Tensile strength, MPa 24 23 26 Elongation at break, % 700 730 700 M100, MPa 0.8 0.8 0.8 M300, MPa 2.6 2.5 2.6 Hardness, IRHD 42 40 41 Resilience, % 84 84 85 Compression set, 22 h 70°C, % 12 5 11

> 0.1 1.7

0.2 1.5

0.4 3.8

The in situ treatment of silica with silane is commonly adopted for mixing silica with rubber rather than the use of pre-reacted silica-silane. Compared to mixing carbon black, the in situ mixing of silica-silane in rubber requires optimal

#### **Table 7.** *Physical properties of DPNR.*

### *Silica-Reinforced Deproteinized Natural Rubber DOI: http://dx.doi.org/10.5772/intechopen.85678*


*\*Rubber formulation: rubber 100, N234 60, ZnO 3, StA 2, 6PPD 2, Wax 1, TDAE 8, CBS 1.5, S 1.5, cured at 150°C for 6 min.*

#### **Table 8.**

*Silicon Materials*

**3. Carbon black reinforcement of DPNR**

Compression stress relaxation: 25% strain,

*Typical vulcanizate properties of DPNR-CV.*

*(MRB) Monograph No. 10, C&D Trading, Kuala Lumpur, (2003).*

7 day/23°C, %

*Lumpur, (2003).*

**Table 6.**

The reinforcing of DPNR by carbon black has been studied in the past [46, 47]. For mixing carbon black and natural rubber, a high reinforcement can be obtained with good dispersion of filler as there is strong physical interaction between the carbon black and the rubber. DPNR-CV is a grade of viscosity stabilized at between 60 and 70 Mooney units. The typical vulcanizate properties of DPNR-CV in comparable to SMR CV is shown in **Table 6** [46]. DPNR-CV gives lower water absorption and compression stress relaxation. **Table 7** shows the physical properties of DPNR filled with carbon black at 50 phr loading and cure using EV system [46]. Similar results are observed where DPNR gives lower water absorption and compression stress relaxation.

The recent evaluation of DPNR (Pureprena) shows that its physical properties are comparable to SMR CV and SMR 10 (**Table 8**). Comparison of DPNR with synthetic polyisoprene (IR) is reported where DPNR shows similar tensile properties and low water absorption to IR (**Table 9**) [48]. The rubber compound using DPNR with total nitrogen content adjusted in the range of 0.12–0.3% by weight exhibits an improved low hysteresis loss property, excellent abrasion resistance, and remarkably excellent

**Properties DPNR-CV SMR CV SMR L** Tensile strength, MPa 33 32 33 Elongation at break, % 570 550 520 M100, MPa 2.4 2.9 2.7 M300, MPa 11.5 13.3 14.5 Hardness, IRHD 60 63 59 Resilience, % 69 68 70 Volume swell in water: 7 day/23°C, % 0.6 0.9 0.9

*\*Rubber formulation: rubber 100, N330 35, ZnO 5, StA 2, TBBS 0.7, S 2.25. Cheang KT, Rais AR, Basir KB. Deproteinised Natural Rubber (DPNR), Malaysian Rubber Board (MRB) Monograph No. 10, C&D Trading, Kuala* 

**Properties DPNR CV SMR CV** Tensile strength, MPa 26 27 Elongation at break, % 520 480 M300, MPa 11.3 13.5 Resilience, % 63 67 Hardness, shore A 52 55 Volume swell in water: 7 day/23°C, % 0.9 1.3 Compression stress relaxation: %, 25% strain, 7 day/23°C 8.6 11.7 *\*Rubber formulation: rubber 100, N774 50, ZnO 5, ZEH 2, Permanex TQ 2, MOR 1.44, TBTD 0.6, S 0.6, cured at 150°C for 20 min. Cheang KT, Rais AR, Basir KB. Deproteinised Natural Rubber (DPNR), Malaysian Rubber Board* 

10.5 12.4 11.5

tear resistance which is advantageous to be used for tire tread [49].

**50**

**Table 7.**

*Physical properties of DPNR.*

*Physical properties of DPNR (Pureprena).*


*\*Rubber formulation: rubber 100, N774 20, ZnO 4, ZEH 2, TMQ 2, accelerator 1.44, accelerator 2 0.7, S 0.7.*

*# Pureprena.*

*##SK1-3.*

*Abd Rahim R, Zaeimoedin TZ, Muhamad AK, Sarkawi SS. New Process Deproteinised Natural Rubber (Pureprena): Raw Rubber, Processability and Basic Physical Properties, Malaysian J. Analytical Sciences. 2016; 20(5):1145-1152.*

#### **Table 9.**

*Comparison of physical properties of DPNR with IR.*
