This study examined the processing and curing properties of rubber sheets made from ammonia-preserved natural rubber latex compared to sodium sulphite-preserved latex. The raw rubber properties of volatile matter content and plasticity retention index were affected by ammonia preservation, with plasticity retention index decreasing as ammonia concentration increased. Mooney viscosity was not impacted by ammonia concentration. When compounded into rubber, the ammonia-preserved sheets showed curing characteristics suitable for use in tire manufacturing. This research demonstrated that ammonia can be used as an effective natural rubber latex preservative.

1. Curing and Mechanical Properties
of a Tyre which is made of a Rubber
Compound Based on Sheet Rubber
Manufacture from Ammonia
Preserved Latex
R.G.N Lakmali
Plastic and Rubber Institute,
Sri Lanka

2. Out Line
•Introduction
•Research Objectives
•Methodology
•Result and Discussion
•Conclusion
•References
•Acknowledgement

3. INTRODUCTION
•Natural Rubber Latex is the major
synthesized commercial product which is
obtained from the rubber (Heveabrasiliensis)
tre
•There are different types of rubber made
from field latex for many purposes

4. They are
•Crepe rubber
•Ribbed Smoke Sheet (RSS)
•Technically Specified Rubber(TSR)
• Scrap Rubber

5. •Ribbed smoked sheet is the most popular
and is available for volume consumption
•RSS is consists of coagulated rubber sheets,
dried using smoke
•RSS is mainly used in automobile tyre
manufacturing

6. RSS Manufacturing Process
Collection of Latex
Standardization
Coagulation
Milling
Smoking
Sorting,Greading and Packing

7. This study was carried out to study the
processing characteristic of latex into RSS
rubber and the raw rubber properties and
curing characteristics of rubber composites
made out of ammoniated natural rubber
latex in comparison with the same
properties of sheet rubber made out of
sodium sulphite

8. Research objectives
•To study the Raw rubber properties of
ammonia preserved latex on Ribbed Smoke
Sheet manufacturing
•To study the curing characteristic of ammonia
preserved latex on Ribbed Smoke Sheet
•To study the properties of rubber compound
which made from ammonia preserved latex on
Ribbed Smoke Sheet to manufacturing new tyre
compound

9. Methodology

10. Waiting
period of
latex
(days)
Preservative and its concentration on latex
Control Na2SO3
(0.05%)
NH3 (0.05%) NH3 (0.10%) NH3 (0.15%) NH3 (0.20%)
0 C0 Na5 N 0.05-0 N 0.10-0 N 0.15-0 N0.20-0
1 - - N 0.05-1 N 0.10-1 N 0.15-1 N0.20-1
2 - - N 0.05-2 N 0.10-2 N 0.15-2 N0.20-2

11. Raw Rubber Properties
•Volatile Matter Content(VMC)
•Mooney Viscosity
•Un-aged Rapid Plasticity (P0) and Plasticity
Retention Index (PRI)
•MINITAB software and Factor factorial CRD design were
used for this experimental design under General Liner
Method(GLM) to analysis purposes

12. Result and Discussion

13. Treatment(Concentration) No of day Mean VM
Control(0) 1 0.498153283
0.05 % Na2SO3 1 0.610067984
0.05% NH3 1 0.624707184
0.1% NH3 1 0.628775747
0.15% NH3 1 0.613766587
0.15% NH3 2 1.329399675
0.2% NH3 1 0.797483842
0.2% NH3 2 0.726557103
0.2% NH3 3 0.43054807
VMC for each preservative concentration levels and days

14. R-Sq Value = 99.98%
(R-Sq >80%)
•The volatile matter content is depending
on the ammonia concentration of the
sheet and with the increasing of the
ammonia concentration the VMC is
increased.

15. treatment
day
0.200.150.100.050.00
321321321321321
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
MeanofVM(%)
VMC under different preservative concentration levels and days

16. Treatment(Concentration) No of day Mooney Viscosity
Control(0) 1 75
0.05 % Na2SO3 1 77
0.05% NH3 1 76
0.1% NH3 1 75
0.15% NH3 1 79
0.15% NH3 2 79
0.2% NH3 1 74
0.2% NH3 2 76
0.2% NH3 3 77
Mooney Viscosity For Each Preservative Concentration Levels And Days

17. R-Sq Value = 72.12%
(R-Sq <80%)
•There for the samples have not the effect on
its mooney viscosity by preservation of sheet
with ammonia. The mooney viscosity is not
depending on the ammonia concentration of
the sheet.

18. Treatment
Date
0.200.150.100.050.00
321321321321321
80
70
60
50
40
30
20
10
0
MeanofMoonyunit
Mooney Viscosity under different preservative concentration levels and days

19. Treatment(Concentration) No of day PRI
Control(0) 1 87.40
0.05 % Na2SO3 1 93.80
0.05% NH3 1 94.85
0.1% NH3 1 91.03
0.15% NH3 1 81.16
0.15% NH3 2 81.46
0.15% NH4 3 81.63
0.2% NH3 1 79.00
0.2% NH3 2 82.11
0.2% NH3 3 85.20
PRI for Each Preservative Concentration Levels and Days

20. R-Sq Value = 99.81%
(R-Sq >80%)
•the samples have the effect on its PRI by
preservation of sheet with ammonia.
• With the increasing of ammonia
concentration the PRI has dropped down of
each sheet.
Due to the over drying and heating, phenolic compounds when
drying sheets, are affect for these incidents.

21. Treatment
Date
0.200.150.100.050.00
321321321321321
100
80
60
40
20
0
MeanofPRI
PRI under different preservative concentration levels
and days

22. CONCLUSION
Raw rubber properties which are Volatile
matter content (VMC) and Plasticity Retention
Index (PRI) affected by the preservation with
ammonia
•PRI will be dropped
•Mooney viscosity is not affected

23. REFFERENCES
•Karunanayake, L LeelaWanigatunga, Perera, P L Senanayake C and
SriyanthiWeeraman, H. Raw Rubber and Latex Properties of Clonal
Rubber. Bulletin of the Rubber Research Institute ofSri
LankaVol40,pp17-24, (1999)
•Chukwu, M NIdiagha,J A and Ihuezor, M O. Effect of Acid Coagulation
Level on The Plasticity Retention Index (PRI) of Natural
Rubber,Multidisciplinary Journal of Research DevelopmentVol15 No
3(2010)
•KulchanatPrasertsit, NamthipRattanawan, and JuraivanRatanapisit.
Effects of wood vinegar as an additive for natural rubber products,
Songklanakarin J. Sci. Technol.Vol33 (4), pp (2011)

24. ACKNOWLEDGEMENT
•Dr.Susantha Siriwardhane,Internal Supervisor
Head, Department of Chemical and Process
Engineering,Rubber Research Institute (RRI) at
Rathmalana
•All members of Plastic and Rubber Institute
and RRI