Alternative Chemical Used for Dirt Determination in Standard Malaysian Rubber (SMR) Testing
M.K Noraziah, J.Sa’ari, K.Ruth, Faridah H.A.H & A. R. Ruhida OUTLINE
• Introduction • Objective • Materials & Methods • Results & Discussion • Conclusion INTRODUCTION
SMR Scheme • Introduced in 1965 • Revised in 1970, 1979 & 1991 INTRODUCTION
SMR SPECIFICATION SCHEME w.e.f 1 OCTOBER 1991 INTRODUCTION
DIRT ANALYSIS • the foreign matter in raw natural rubber which fails to pass a sieve of 44 µm (325 mesh size) side-square aperture • have adverse effects on certain vulcanizate properties such as fatigue and tensile strength, thus lowering the dynamical property of the rubber INTRODUCTION
• solvent addition gives partial dissolution and swelling of the gel ~ caused by the cross linked gel fraction in rubber solution • for a good dissolution rubber peptizer is added • this will causes polymer scission and the ultimate destruction of the weak network • the rate of dissolution is accelerated at higher temperature
Ref: Lau, C.M. & Ong, C.O., Basic Factors Affecting SMR Tech Prop, Training Manual on NR Processing, 1979 INTRODUCTION
• Current test method is using turpentine as a dissolution solvent • Very hazardous in case of ingestion • May cause damage to the following organs: Central nervous system (CNS) Upper respiratory tract Gastrointestinal tract Urinary system Kidneys Lungs Skin, eyes, ears, nose/sinuses OBJECTIVES
1. To identify alternative dissolution solvent for dirt determination in SMR testing.
2. To replace turpentine with less hazardous and friendlier solvent. MATERIALS & METHODS
Materials Solvents • SMR 10 • Mineral Turpentine • SMR 20 (Control) • SMR L • Kerosene • SMR CV60 • Dimethylformamide • SMR GP • Toluene • White Spirit TEST METHOD
Sampling Procedure • SMR Bulletin No. 7 Part B.1
Sample Homogenization • SMR Bulletin No. 7 Part B.2 • SMR Bulletin No. 7 Part B.3
Dirt Testing • SMR Bulletin No. 7 Part B.4 SAMPLE HOMOGENIZATION
• Samples passed through 2- roll mill • Size: 150 x 300 mm (6 times) • Friction Ratio: 1:1.4 • Roller Gap: 1.65 0.16 mm • Temperature: Room temp. SAMPLE PREPARATION
1. Cutting of sample strips
2. Samples prior to dissolution
3. Dissolution process CHEMICAL ANALYSIS
4. Sample filtration
5. Drying process
6. Weighing process RESULT EXPRESSION
B – A Dirt Content (%) = X 100 C
where
A is the mass of initial sieve, g
B is the mass of sieve with dirt, g
C is the mass of test piece, g QUALITY CONTROL PROCEDURE
1. Checking the boiling temperature of the solvent by using Differential Scanning Calorimetre (DSC)
2. Positive identification of solvent used by using Fourier Transform Infrared Spectroscopy (FTIR) RESULTS AND DISCUSSION PRELIMINARY FINDINGS
Boiling Dirt Solvent Point Content Observation Remarks (oC) (%) Mineral Turpentine 160 0.092 Normal USD1.17/L (Control) Longer time needed to Toluene 111 0.095 USD71.71/L achieve proper dissolution Slight swollen Dimethylformamide 153 NA USD128.43/L of test piece Kerosene 168 0.087 Normal USD1.48/L White Spirit 187 0.073 Normal USD19.02/L Note: NA = not available MEAN VALUES
Mean (%) Grade Kerosene Turpentine SMR L 0.004 0.004 SMR GP 0.051 0.048 SMR CV 0.013 0.013 SMR 10 0.034 0.034 SMR 20 0.028 0.029
F-test: There is no significant difference between the precision of dirt content results for both solvents. COEFFICIENT OF VARIATION (%)
Coefficient of Variation (%) Grade Kerosene Turpentine SMR L 2.63 15.91 SMR GP 4.01 0.46 SMR CV 5.34 18.6 SMR 10 1.96 2.05 SMR 20 8.19 5.12 REPEATABILITY AND REPRODUCIBILITY
Repeatability (Sr) Reproducibility (SR) Grade Kerosene Turpentine Kerosene Turpentine
SMR L 0.0016 0.0023 0.0016 0.0021
SMR GP 0.0027 0.0027 0.0027 0.0035
SMR CV 0.0051 0.0066 0.0052 0.0076
SMR 10 0.0043 0.0051 0.0042 0.0047
SMR 20 0.0035 0.0044 0.0040 0.0043 MEASUREMENT OF UNCERTAINTY (MU)
Grade Kerosene Turpentine SMR L 0.01 0.01 SMR GP 0.03 0.04 SMR CV 0.02 0.02 SMR 10 0.02 0.03 SMR 20 0.02 0.02 ADVANTAGES
Kerosene Turpentine Hazards Less hazardous Very hazardous Identification Flash points 38 C 35 C Vapor pressure 0.1 kPa 76.9 kPa (@20 C) HMIS regulations 2 3 – Fire hazard QUALITY CONTROL PROCEDURE (DSC)
27.12.2007 13:33:06
turpentene o Kerosene (Tb = 197.5 C) ^exo ^exo kerosene 27.12.2007 13:34:16 mW turpentene, 27.12.2007 12:27:12 -10.79e+03 mJ turpentene, 15.2300 mg -708.31 Jg^-1 mW Integral kerosene, 27.12.2007 11:56:14 0 Method: kerosene 166.95 °C normalized kerosene, 13.7200 mg 150.0-280.0°C 10.00°C/min 185.26 °C Onset 0 Method: kerosene 195.23 °C Peak 150.0-280.0°C 10.00°C/min Endset 10.00 °Cmin^-1 Heating Rate
-20 -5
-10 -40
Integral -4346.58 mJ normalized -316.81 Jg^-1 -15 Onset 184.92 °C Peak 200.46 °C Endset 232.10 °C -60 Heating Rate 10.00 °Cmin^-1 °C -20 270 260 min 250 12 -80 240 11 e SW 8.10 10 R 230 -25 STA 220 9 210 8 200 7 6 -100 190 -30 180 5 170 4 160 3 150 2 -35150 160 170 180 190 200 210 220 230 240 250 260 270 °C -120 1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 min Lab: METTLER Lab: METTLER STARe SW 8.10 QUALITY CONTROL PROCEDURE (FTIR)
FTIR SPECTRUM Collection time: Wed Dec 26 11:35:31 2007 Wed Dec 26 16:34:08 2007
RR/0712/0472 Noraziah Kassim KEROSENE pyr 2.2 RR/0712/0473 Noraziah Kassim TURPENTINE pyr
2.0
1.8
1.6
1.4
1.2 2 9 2 6 2 9 5 8
1.0 A b so rb a n ce Kerosene
0.8
0.6 2 8 4 6
0.4
8 0 6 3 0 1 6
0.2 6 9 8 1 6 0 8 Turpentine 1 0 3 8 0.0
3500 3000 2500 2000 1500 1000 Wavenumbers (cm-1) CONCLUSION
• There is no significant difference between the mean values recorded for the dirt content using both solvents.
• Values of coefficient of variation for kerosene were observed to be in the range of 2% – 8%. Whilst the MU, Sr and SR generated were in the acceptable ranged.
• Thus, it is recommended for kerosene to be used as an alternative dissolution media for dirt content determination in SMR testing. ACKNOWLEDGEMENT Thank You to;
1. Director General of MRB for her permission to present this paper 2. Directorate members of MRB 3. Head of Materials Characterization Unit (MCU) 4. Colleagues of MCU 5. Staff of SMR Control Lab,MCU Thank You