Some Properties of Carbon Nanotube Filled Natural

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R u b b e r Technology Developments

Rubber Technology Developments

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Some Properties of Carbon Nanotube Filled Natural Rubber Using Rubber Latex Masterbatch Technique NIK INTAN NIK ISMAIL#, MANROSHAN SINGH, ASRUL MUSTAFA AND MD ARIS AHMAD Rubber Research Institute of Malaysia, Malaysian Rubber Board ABSTRACT

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This paper relates a preliminary investigation on the viability and potential utilization of carbon nanotube latex masterbatch in natural rubber compounding. In the present work, carbon nanotube was mixed with natural rubber latex to prepare carbon nanotube masterbatch which was subsequently used in dry rubber compounding. The incorporation of carbon nanotube was shown to improve the surface electrical resistivity. Judicious use of a dispersing agent in the preparation of carbon nanotube latex masterbatch indicated subsequent improvement in dispersibility of the carbon nanotube in natural rubber as shown by themicroscopy method. However, no enhancement in mechanical properties was observed in the present investigation.

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Figure 8. Mass Spectrum (m/z ratio) of D12Perylene at 19.31 minutes.

Nanostructured materials have gained great importance in the past decade on account of their wide range of potential applications in many areas. Amongst the nano-materials, large interest is devoted to carbon nanotubes (CNT) which exhibit exceptional electrical and mechanical properties and can therefore be used for the development of a new generation of composite polymer materials. Nevertheless, poor dispersion and inadequate interfacial bonding1 limit the full utilization of carbon nanotubes for polymer reinforcement. Thus, these significant challenges must be overcomed before the potential utilization in polymer of CNT is realized.

MATERIALS AND METHOD

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Figure 9. Mass Spectrum (m/z ratio) of Indeno (1,2,3-c,d) Pyrene at 24.39 minutes.

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Scan 3075 (25.658 min): Benzo (g,h,i) perylene 276

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Figure 10. Mass Spectrum (m/z ratio) of Dibenzo (a,h) anthracene at 24.66 minutes.

Figure 11. Mass Spectrum (m/z ratio) of Benzo (g,h,i) perylene at 25.66 minutes.

CONCLUSION

6. ISO 21461:2006(E) Rubber – Determination of the aromaticity of oil in vulcanized rubber compounds.

Preparation of Carbon Nanotube Masterbatch

The use of CNT as a filler in rubber is an emerging research area which promises new rubber materials with remarkable strength and electrical conductivity. Adequate work has been done to demonstrate the possibility of incorporating carbon nanotube in natural rubber2–5. Various techniques have been attempted to optimize the nanotube dispersion within the polymeric medium. These include solution mixing, sonication, coagulation, melt compounding, in situ mini emulsion, polymerization, oxidation or chemical functionalization of the tube surface and also use of surfactants.

NR latex with lignosulfonate (LS) and muti-walled carbon nanotube purchased from Shenzen Nanotech Co., Ltd., China were used to prepare carbon nanotube rubber masterbatch according to the formulation shown in Table 1. The addition sequences for MB 3 differed from MB 2 whereby in the former, CNT was dispersed with potassium hydroxide and a dispersing agent prior to blending with rubber latex. After blending, all the mixtures were stirred until homogeneity. The resulting masterbatch was dried in a circulating air oven at 70ºC for 72 hours.

At the Rubber Technology Centre, exploratory work on CNT filled natural rubber was carried out with the aim of investigating the viability of incorporating multi walled CNT in rubber matrices. In the present work, an environmental friendly approach by co-coagulating CNT with natural rubber latex prior to incorporation in rubber compounding was carried out. The carbon nanotubes were dispersed in natural rubber latex and subsequently used as a masterbatch.

Compounding

#Corresponding author (e-mail: nkintan@lgm.gov.my)

277 274

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The CNT was incorporated into natural rubber through compounding using a formulation for tyre black side wall compound which was obtained and modified from the MRPRA Natural Rubber Formulary and Property Index. The original formulation was retained as control. Experiments were carried out by addition of CNT masterbatch and the resulting CNT reinforced natural rubber vulcanisates were evaluated for their cure behaviour, mechanical and electrical properties.

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INTRODUCTION

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The CNT masterbatch was used in rubber compounding as indicated in Table 2. Mixing was carried out using a Haake internal mixer. The compound cure characteristics were analysed using a Monsanto ODR 2000 at a temperature of 150ºC and a frequency of 1.66 Hz. The characteristics of the cure consisted of induction scorch or safety time (TS2),

Work is currently in progress in order to fine-tune the technique of analyzing PAHs by using GC-MSD. The test method once developed will be validated against the existing test methods of IP346 and ISO 21461 (Rubber Vulcanised – Determination of aromaticity of oil in vulcanised rubber compounds) respectively. REFERENCES 1. J.E. POCKLINGTON (1998), Tire Technol. Int. Vol. 43. 2. (1999) Mobile Europe Lubricants Limited, UK, Oils without labels, Tire Technol. Int. Vol. 10. 3. Directive 2005/69/EC of the European Parliament and of the Council of 16 November 2005, Official Journal of the European Union, 9.12.2005, pgs. 51–54. 4. Question and Agreed Answers, Concerning the Implementation of Directive 76/769/EEC on the Restrictions to Marketing and Use f Dangerous Substances, European Commission, Version 2:16 July 2007, pgs. 1 – 7. 5. Institute of Petroleum 346:1998 (IP346:1998).

7. H. PREST, Solid-Phase Extraction and Retention-Time Locked GC/MS Analysis of Selected Polycyclic Aromatic Hydrocarbons (PAHs), Application Notes of Agilent Technologies, 5968-4188EN, www.agilent.com/chem. 8. H. PREST AND D.W. PETERSON, New Approaches to the development of GS-MS SIM (Selected Ion Monitoring) Acquisition and Quantitation Methods, Agilent Technologies, 5988-4188EN, www.agilent.com/chem. 9. H. PREST, Solid-Phase Extraction and Retention-Time Locked GC/MS Analysis of Selected Polycyclic Aromatic Hydrocarbons (PAHs), Application Notes of Agilent Technologies, 5968-4188EN, pg. 7, www.agilent.com/ chem. 10. H. PREST, Solid-Phase Extraction and Retention-Time Locked GC/MS Analysis of Selected Polycyclic Aromatic Hydrocarbons (PAHs), Application Notes of Agilent Technologies, 5968-4188EN, pgs. 3 – 4, www.agilent.com/ chem. 11. (1998) Bulletin 910, Guide to Solid Phase Extraction, SUPELCO Technical Notes, Sigma-Aldrich Co. pgs 1–12.

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time to optimum cure (T95) and state of cure (MH-ML). The vulcanization was carried out at 160ºC for 4 min using a hot press.

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TABLE 1. PREPARATION OF CNT-RUBBER MASTERBATCH

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Ingredients* (Parts by weight)

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Figure 3. Mass Spectrum (m/z ratio) of Benzo (a) anthracene at 14.19 minutes.

Figure 2. The Total Ion Chromatogram (TIC) of authentic standards of PAHs and deuterated standard (D12 Perylene) for Retention Time Locking (RTL).

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216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237

5000 0 240

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CNT

45

45

45

Phenolic polymer dispersing agent

–

2.7

2.7

Potassium hydroxide (1% solution)

100

100

100

*Addition of ingredients was in sequence with the exception of MB 3

Surface resistance =

Vd As

…1

Surface resistivity =

Rs  2 ln Rb/Ra

…2

Microscopy The films were first cut to about 1cm  1cm and cleaned with acetone to remove dust and stains on the surface of the films. Tweezers were used next to place the films on a slide holder. The surface of the films was then viewed through a Carl Zeiss Axiotech Image Analyzer coupled with a high resolution microscopy camera (Axiocam MRc Rev 3) before capturing the images using the Axiovision Rel 4.6 Software (Carl Zeiss Imaging Systems).

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TABLE 2. RUBBER COMPOUND FORMULATIONS Ingredients (parts by weight) SMR L

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Figure 5. Mass Spectrum (m/z ratio) of Benzo (b) fluoranthene at 17.74 minutes.

Figure 4. Mass Spectrum (m/z ratio) of Chrysene at 14.28 minutes.

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Measurements were conducted using a Megohmmeter Ohm-Stat RT 1000 (Static Solutions Inc.). The measurements were carried out on both surfaces of the samples. Surface

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Electrical Surface Resistivity Measurements

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The tensile strength, elongation at break (Eb) and modulus at 100% strain (M100) and 300% (M300) were measured at a crosshead speed of 500 mm/min according to ISO 37. The compression set was measured in accordance to ISO 815. Measurements of air permeability to obtain permeability coefficient Q, were carried out at constant volume according to the procedures specified in IS0 2782.

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Natural rubber latex (60% drc)

Mechanical Properties and Air Permeability

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CNT Masterbatch MB 1 MB 2 MB 3

resistance (Rs) indicates the ratio of a DC voltage (Vd) to a current flow (As) between two electrodes of a particular material, whilst surface resistivity is a measurement of a material surface resistance that is determined by the ratio of DC voltage drop (Vd) per unit length (L) to the surface current per unit width6. The latter could be correlated to surface resistance by Equation 2, whereby, Ra is the outer radius of the centre electrode and Rb is the inner radius of the outer ring electrode of a concentric ring probe. Surface resistivity is expressed in ohms per square (ohms/sq), independent of the physical dimension of the material; hence the term square could be related to any unit of surface area. By measuring the surface resistivity, static dissipation effect of a material could be determined, in which higher level of static dissipation is indicated by lower values of surface resistivity.

®

Control

Compounds Compound 1 Compound 2

Compound 3

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Buna CB 25

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Zinc oxide

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Black N375

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Shellflex 250 MB

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Figure 6. Mass Spectrum (m/z ratio) of Benzo (k) fluoranthene at 17.86 minutes.

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Figure 7. Mass Spectrum (m/z ratio) of Benzo (a) pyrene at 19.07 minutes.

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COPYRIGHT © MALAYSIAN RUBBER BOARD

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RESULTS AND DISCUSSIONS

compounds showed relative increase in air permeability as compared to the control. This is probably due to the poor orientation of CNT in the rubber matrix. Further study is required to improve this particular property in future work.

Compound Cure Properties Table 3 shows the effect of CNT masterbatch incorporation in the rubber compounding. It can be observed that the time to optimum cure (T95) is reduced by the addition of Multi Wall Carbon Nanotubes masterbatch as compared to the control. In general, the safety scorch time becomes longer by the addition of MWNT masterbatch and SLS MWNTs masterbatch in the compound. The change in the safety scorch may be controlled by reducing the amount of phenolic polymer type dispersing agent used. Mechanical Properties and Air Permeability The effect of the incorporation of CNT masterbatch in natural rubber vulcanisates is shown in Table 4. The results suggested that the incorporation of CNT in the form of masterbatch may increase the modulus properties and compression set values of the vulcanisates, while the tensile strength and elongation at break of the vulcanisates are reduced. The reduction in permeability strongly depends on the aspect ratio and the alignment of the nanofillers7 in rubber matrices. Excellent gas barrier properties would only be observed in rubber nanocomposites having fully exfoliated filler orientation. Results from Table 4 suggest that the incorporation of CNT masterbatch in rubber compounding negatively affected the air permeability properties. All

Electrical Surface Resistivity The results of surface resistivity measurements are shown in Table 5. In general, all the compounds incorporating the CNT masterbatch exhibited marked reduction in surface resistivity in comparison to the control which can be an advantage to use this material as a form of conductive composite in future. This may suggest that percolation threshold of the conducting CNT to form inter-bridging network is attained and this occurrence imparts electrical conductivity. This may further results in increasing static dissipative properties. However, in the present investigation this phenomenon is surface related while the changes in the bulk � of the rubber are unknown. Changes in the bulk of� the rubber and also the difference in resistivity exhibited � by different voltage discharge are yet to be established in future work. Microscopy �� The micrograph of pristine CNT is shown the Figure 1. The CNT exhibited the tendency to form agglomeration and aggregation, which may lead to poor ability ��to disperse well in natural rubber. Thus, some form of modification is required �� to ensure good dispersion. In the present investigation, the CNT was dispersed in latex with surfactant to form the CNT masterbatch before the incorporation in compounding.

Control

Compound 1

Compound 2

Compound 3

27.71

28.39

29.12

29.11

TS2 (min)

2.07

2.31

2.33

2.19

T95 (min)

6.24

5.03

4.50

4.28

38.10

44.40

43.20

46.50

Mooney scorch (120ºC, min)

TABLE 4. MECHANICAL PROPERTIES AND AIR PERMEABILITY RESULTS Control

Compound 1

Compound 2

Compound 3

Modulus 100% (MPa)

1.87

2.64

2.67

2.59

Modulus 300% (MPa)

10.30

12.31

12.17

11.34

Tensile strength (MPa)

20.40

19.58

19.70

16.00

Elongation at break (%)

473.60

424.90

436.00

379.00

Compression set (1d/23ºC) Air permeability (cm2sec–1atmos–1) All values are median of three readings.

5.80 7.03  10–19

7.40 6.54  10–17

�

7.40 6.23  10–17

6.90 7.0649  10–17

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TABLE 3. COMPOUND CURE PROPERTIES

Delta torque

on the percentage of bay region hydrogens (% HBAY). The limits of 1 mg/kg of Benzo (a) pyrene (BaP) concentration in aromatic oils, which is one of the eight regulated PAHs and 10 mg/kg for the total of eight regulated PAHs content are considered kept, if the vulcanized rubber compounds do not exceed the limit of 0.35% bay region hydrogens as measured and calculated by the method of 1H NMR.

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Figure 2 illustrated the Total Ion Chromatogram (TIC) from the series of standard compounds of PAHs. The TIC contained a total of six standard compounds of PAHs namely Benzo(a)anthracene (BaA), Chrysene, Benzo(b) fluoranthene (BbFA), Benzo(k)fluoranthene (BkFA), Benzo(a)pyrene (BaP) and dibenzo(a,h)anthracene (DBAhA) which are regulated under the EU Directive, a deutrated standard compound namely D12Perylene used for RTL as well as two other standard compounds namely Indeno (1,2,3-c,d) pyrene and Benzo (g,h,i) perylene respectively. It must be emphasized that the analysis was carried out following the � chromatographic condition which has been set up specifically for analyzing PAHs. The identification of individual PAHs was confirmed based on the mass spectrum of each of the selected �� ions at specific retention times as illustrated in � � Figures 3–11. �

��

�

At this point of time work is in progress to identify and measure the concentration of individual PAHs in samples of � aromatic oils, passenger car tyres�� and motorcycle tyres based �� on the mass spectrum (MS) of the selected ions at specific �� retention times. The �� first ion (m/z) for each compound is known as the quantitation ion9. The corresponding ions for each compound of PAHs are illustrated in Table 1 for reference purposes.

Figure 1. The bay hydrogen atoms of non-linear PAHs with three or more fused rings.

The newly developed method for measuring content of PAHs in samples of aromatic oils and samples of tyres A reliable test method is needed prior to full implementation of Council Directive 76/769/EEC, the Malaysian Rubber Board (MRB) has taken an initiative to carry out some method development works for identifying and measuring the concentration of PAHs in some samples of aromatic oils as well as some passenger car tyres and motorcycle tyres by using gas chromatograph – mass selective detector (GCMSD). As far as the identification and measurement of the concentration of PAHs in the aromatic oils is concerned, the method used was quite straight forward as it involved direct analysis of PAHs. This was done by diluting the oils in an appropriate solvent at a certain ratio prior to injecting approximate volume of 1 µl of the diluted sample into a column of GC-MSD. As the analysis of PAHs requires for samples and standards to be protected from light in order to avoid potential for photochemical destruction by fluorescent lamps or sunlight, the use of amber vials and aluminum foils were employed throughout the analysis7. An appropriate GCMS SIM8 acquisition method equipped with Retention-Time Locking (RTL) was utilized in order to increase the sensitivity for detection of ions most indicative of the compounds of interest.

TABLE 1. THE PAHs COMPOUND LIST AND NOMINAL VALUES OF SELECTED IONS (M/Z). THE RTL COMPOUND IS D12PERYLENE PAHs Compound

Corresponding Ions (m/z ratios)

Benzo (a) anthracene* Chrysene* Benzo (b) fluoranthene* Benzo (k) fluoranthene* Benzo (a) pyrene* D12Perylene (RTL Compound) Indeno (1,2,3-c,d) Pyrene Dibenzo (a,h) anthracene* Benzo (g,h,i) perylene

226, 228 226, 228 250, 252, 253 250, 252, 253 250, 252, 253 264, 265 274, 276, 277, 278 274, 276, 277, 278 274, 276, 277

* Six out of eight regulated PAH compounds that are regulated by EU Directives.

Unlike the analysis of PAHs in aromatic oils samples, which was straight forward, the identification and measurement of individual PAHs in tyre samples however would require for involvement of several complicated sampling steps. Samples must first be subjected to solvent extraction followed by concentration of the organic analyte. The concentration step of the organic analyte itself would require for another phase separation technique10,11 to be performed in order to clean up the solvent extract .

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Analysis of Poly Aromatic Hydrocarbons (PAHs) in oils and tyre samples FARIDAH HANIM ABDUL HANAN Rubber Research Institute of Malaysia, Malaysian Rubber Board

INTRODUCTION Highly aromatic oils have been traditionally and widely used as extender oils which are added to rubber compounds during the production process for tyres and other rubber goods in order to achieve an acceptable processability1,2. These oils are highly popular as they have an impact on certain performance characteristics of the final product. They are also economically viable since they are quite cheap hence affordable. These highly aromatic oils are known to contain increased polycyclic aromatic hydrocarbons and can thus be called poly aromatic hydrocarbons (PAHs) rich oils; many of which are known as suspected carcinogens hence regulated. On November 16, 2005 the European Union (EU) through Directive (2005/69/EC)3 has amended and incorporated into Council Directive 76/769/EEC4 the restrictions on the marketing and use of PAH-rich extender oils and blends used as extender oils for the production of tyres. Under this Directive eight different types of PAHs namely Benzo(a) pyrene (BaP), Benzo(e)pyren (BeP), Benzo(a)anthracene (BaA), Chrysen (CHR), Benzo(b)fluoranthene (BbFA), Benzo(j)fluoranthene (BjFA), Benzo(k) fluoranthene (BkFA) and dibenzo(a,h)anthracene (DBAhA) have been classified as carcinogens hence regulated. It was also stated in Annex 1 of Directive 76/769/EEC that tyres produced after 1st January 2010 may not be placed on the market if they contain extender oils exceeding more than 1 mg/kg of BaP or more than 10 mg/kg of the total sum of the eight listed PAHs. Hence it is important to proactively develop reliable test methods with regards to the measurement of the content and identification of the eight regulated PAHs in extender oils and in tyres prior to full implementation of the proposed Directive. Available test methods for measuring the content of PAHs in aromatic oils There are at present two different types of test methods available for measuring the contents of PAHs in aromatic oils. One applicable method that is permitted for measuring the content of PAHs in aromatic oils is the IP346 (Institute of Petroleum 346:1998)5 analysis method. Another applicable method is by using 1H NMR. IP346 The IP346 test method is acceptable provided certain conditions are met. The additional conditions are necessary as the IP346 method does not measure the PAHs content directly. In fact IP346 measures the total content of

polycyclic aromatic compounds (PCAs) rather than the PAHs content. What are PCAs substances? The PCAs are groups of substances to which PAHs belong. However, the amount of PAHs present is very small. The legal allowable limit for PAHs content in aromatic oils is 1 mg/kg of Benzo(a)pyrene (BaP) concentration, which is one of the eight regulated PAHs and is chemically detected as representative of PAHs and 10 mg/kg for the total of eight regulated PAHs content. This condition is considered met if the total content of PCAs is found to be less than 3% by using the IP346 test method. In another words the PCAs content of less than 3% is taken as proxy measurement for a total PAHs content of 10 mg/kg. For this proxy measurement to be valid depends on one condition that is, the ratio between the PAHs and PCAs content in aromatic oils must not change over time. In order to meet this condition, it requires initial calibration of the measurement of the PAH/PCA ratio and recalibration for every six month, or after any major changes. The IP346 method involves extraction of three to sevenring polycyclic aromatic hydrocarbon compounds through a specific solvent namely Dimethylsulfoxide (DMSO). The extract obtained through IP346, includes the eight PAHs specified by the EU legislation, but it is not limited to these. IP346 has thus been globally accepted by legislators as a tool for classifying and labeling oils hence suitable for predicting the carcinogenic potential for oils used in the tyre industry. It must be emphasized once again that in order for the measurement to be valid, the ratio between the PAHs and PCAs content in the aromatic oils should not change over time. Oils with an IP346 extract below 3% are therefore considered to have PCAs content of less than 3% and hence not considered as carcinogenic. 1

H NMR

Another standard test method that is available for measuring the content of PAHs in aromatic oils is ISO 214616. This standard is based on a principal that bay region hydrogen atoms of non-linear PAHs with three or more fused rings are used to characterize aromaticity of oils by using 1H NMR. Figure 1 shows the hydrogen atoms in the bay region belonging to non-linear PAHs with three or more fused rings. This standard method has been successfully validated in a multiple laboratory crosscheck program and has been published by the ISO committee responsible for acceptance as an ISO method in 2006. This method however will not quantify and identify individual PAHs present in the oil. It can only determine the aromatic character of the oil based

TABLE 5. SURFACE RESISTIVITY Surface resistivity of film (/square) 100 volts 10 volts Control

3.97  107

6.63  107

Compound 1

1.96  106

2.51  106

Compound 2

6.56  106

9.81  106

Compound 3

3.48  106

4.53  106

All values are mean of three readings.

Figure 1. Pristine CNT.

Micrographs of the CNT filled natural rubber shown in Figure 2 suggest the orientation of the CNT at the rubber surface. Compound 1, without surfactant in the masterbatch preparation demonstrated the highest level of agglomeration at the rubber surface in comparison to Compound 2 and 3 where the dispersing agent was in corporated. It is however believed that the dispersability of the CNT was insufficient because the increment in mechanical properties was not observed in both rubber samples. CONCLUSIONS In the present work, carbon nanotube was mixed with natural rubber latex to prepare carbon nanotube masterbatch which was subsequently used in dry rubber compounding. Natural rubber comprising carbon nanotube demonstrated promising results in the enhancement of electrical surface resistivity which relates to the static dissipation properties. Judicious addition of dispersing agent in the carbon nanotube latex masterbatch was shown to increase the overall dispersibility of the carbon nanotube but may not be sufficient to further improve the mechanical properties. It is anticipated that the difficulties in incorporating carbon nanotube in natural rubber is related to its poor dispersion in rubber. In the present

Figure 2. Micrograph of Control and CNT-filled natural rubber vulcanisates. A: Control compound; B: Compound 1 without dispersing agent; C: Compound 2 with dispersing agent added to the CNT prior to latex blending; D: Compound 3 with dispersing agent added to the CNT and latex blend.

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investigation, it was shown that even a slight alteration in processing for instance the change in an addition sequence of the dispersing agent during the preparation of the carbon nanotube latex masterbatch tremendously affected the rubber mechanical properties.


3. MUATAZ, A.A., NAZLIA, G., FAKHRU’L-RAZI, A., GUAN, C.T., EL-SADIG, M. AND DAYANG, R. B. (2005) Multiwall Carbon Nanotubes/Natural Rubber Nanocomposite. Journal of Nanotechnology Online, 1, 1-11.

ACKNOWLEDGEMENTS

4. KUESENG, K. AND JACOB, K.I. (2006) Natural rubber nanocomposite with SiC nanoparticles and carbon nanotube. European Polymer Journal, 42, 220-227.

Assistance rendered by En. Firdaus (UTGT), Che Rasnah, Noorshahila (USTL) and personnel of the Physical Testing Lab is gratefully acknowledged.

5. BOKOBZA, L. AND KOLODZIEJ, M. (2006) On the use of nanotubes as reinforcing fillers for elastomeric materials. Polymer International, 55, 1090-1098.

REFERENCES

6. ESD STM 11.11-2001. Surface Resistance Measurement of Static Dissipative Planar Materials, Electrostatic Discharge Association, Rome, NY.

1. BOKOBZA, L. (2007) Multiwall carbon nanotube elastomeric composites: A review. Polymer, 48, 4907-4920. 2. BOKOBZA, L. AND KOLODZIEJ, M. (2006) On the use of nanotubes as reinforcing fillers for elastomeric materials. Polymer International, 55, 1090-1098.

7. WANG, Z. F., WANG, B., OIA, N., ZHANG H.F., and ZHANG, L.Q (2005) Influence of fillers on free volume and gas barrier properties in styrene-butadiene rubber studied by positrons. Polymer, 46, 719–724.

for the British Government and a different identifying number for each of the other European countries involved). The ‘E’ certifies that the tyre complies with the dimensional, performance and marking requirements of ECE Regulation 30. While the ‘e’ certifies that the tyre complies with the dimensional, performance and marking requirements of DIRECTIVE 92/23/EEC. • Germany and Netherlands have banned the use of certain dyes and chemicals which are not Eco-friendly. USED TYRES SCENARIO IN MALAYSIA Total domestic scrap tyres generated in Malaysia is estimated to be about 15 million units per year. Per capita scrap tyre generated in this country is about 0.8 currently5. As Malaysia’s population grows, the scrap tyre will also build up to reach a projected figure of 25 million by 2020 pt. As demand for vehicles and tyres grows, Malaysia’s scrap tyre per capita is anticipated to increase in tandem. Scrap tyre is expected to reach more than 25 million by 2020. The situation warrants the need for Malaysia to urgently formulate and regulate a national policy on the disposal of such tyres in an environmentally-friendly and non-polluting manner. Malaysia has been involved in various bilateral and multilateral free trade agreements. In these FTAs, Malaysia has placed all used tyres in the exclusion list. This means that the current tariff on used tyres will not be subjected to tariff reduction. However, some of the FTA partner countries questioned Malaysia’s move to place used tyres in the exclusion list and they instead requested Malaysia to gradually liberalize these products.

If Malaysia agrees with this request, it will remove all tariffs on imported used tyres and finally it will allow for unstoppable inflow of all categories and types of used tyres into this country. With free inflow of used tyres, Malaysia will become a dumping site for these tyres from FTA partners particularly the developed partners with huge excess of used tyres awaiting disposal. SUMMARY Maintaining high standards for technical regulations is important to protect human, animal or plant life or health, or the environment. However it is vital that the regulations are not misused for protectionist reasons which impede trade as it can be difficult and expensive for exporters to understand and comply with these regulations. A Technical Barriers to Trade chapter in Free Trade Agreement and World Trade Organization provides the participating countries the opportunity to look at ways of minimizing technical barriers that affect trade specifically with the aim of reducing the transaction costs to business associated with different standards and regulatory requirements. Seriousness of disposal of scrap tyres has led to several countries in the world including Malaysia enforcing regulations and measures of various forms to curb inflow of used tyres into these countries to protect human, animal and plant life and health. There is a need for Malaysia to have a clear national scrap tyre management and disposal laws and regulations. Malaysia also needs to establish an effective mechanism to curb free

flow of foreign used tyres into this country to prevent this country from becoming a dumping site for used tyres from other countries particularly the developed nations with huge excess of these tyres awaiting disposal. REFERENCES 1. SACHIKO MORITA (2007) Environmental Dispute at the WTO: Brazil – Measures Affecting Imports of Retreaded Tyres, Volume 1 Issue 5 October 2007, The Nature of Law The Newletter of LEGEN 2. (2007) Framework for Integrating Environment Issues into Free Trade Agreement, www.mfat.govt.nz/ Trade-and-Economic-Relations/0-Trade-archive/WTO/0-environment-framework.php 3. DALE C. (2003) Agriculture and Environmental Issues in Free Trade Agreements, Volume 4 Number 2, 2003 123-143, The Estey Centre Journal of International Law and Trade Policy, esteyjournal.com 4. S.P. AGARWAL AND RAJESHWAR DAYAL (2003) Volume VI No. 1 July – September 2003 1-12, Technology Exports. Implication of WTO-TBT Agreement on Exports. 5. ABDUL HALIM HASSAN (2006) Volume 6, 2006 5-8, Malaysian Rubber Technology Developments. Disposal of Used Pneumatic Tyres.