scholarly journals Characteristics of natural rubber – carbonized pawpaw seed composites

2020 ◽  
Vol 14 (8) ◽  
pp. 2951-2964
Author(s):  
Emmanuel Osabohien ◽  
Ufuoma Soya ◽  
Nduka Obichukwu Ojeifo

The search for eco-friendly and less expensive fillers and additives has necessitated the use of renewable natural resources of plant origin in rubber compounding. This research work utilized carbonized pawpaw (Carica papaya) seeds as filler in natural rubber compounds in a bid to determining the reinforcing potentials. The carbonized pawpaw seeds (CPS) and dried raw pawpaw seeds (RPS) were separately pulverized, screened with a 75 μm sized test sieve and incorporated into natural rubber, Standard Nigerian Rubber (SNR 10), loaded between 0 – 50 parts per hundred (Phr) of the rubber. The cure characteristics, physicomechanical properties as well as the percentage swelling characteristics of vulcanizates were measured as a function of filler loading and compared with the values obtained using industrial grade carbon black (N330) as a standard reinforcing filler. Results showed that the CPS and RPS filled SNR 10 influenced the cure characteristics and physicomechanical properties of rubber vulcanizates. The scorch and cure times of the vulcanizates decreased as filler loading is increased while maximum torque increased with increase in filler loading. Tensile strength and modulus at 100% strain for all SNR 10 filled vulcanizates increased to optimum level at 40 phr respectively, thereafter decreased, and elongation at break decreased as filler loading is increased. The hardness and abrasion resistance of the vulcanizates increased with increase in filler loading, while compression set and percentage swelling in both petroleum and aromatic solvents decreased as filler loading is increased. The vulcanizates tend to swell more in aromatic solvents than in petroleum solvents. Percentage swelling of the vulcanizates (N330 – SNR 10 < CPS – SNR 10 < RPS – SNR 10) and in the order benzene > toluene > kerosene > diesel solvents. The research work showed that CPS and RPS fillers exhibited considerable reinforcing potentials but somewhat inferior to carbon black, N330. Keywords: Natural rubber, pawpaw seeds, fillers, vulcanizates and reinforcement.

2018 ◽  
Vol 197 ◽  
pp. 12005 ◽  
Author(s):  
Indra Surya ◽  
Mimpin Ginting ◽  
Hanafi Ismail

The cure characteristics, swelling behaviour and tensile properties of carbon black (CB)-filled natural rubber (NR)/chloroprene rubber (CR) blends in the presence of alkanolamide (ALK) were investigated. The NR/CR blends were prepared at 50/50 blend ratio. The ALK was prepared from Refined Bleached Deodorized Palm Stearin (RBDPS) and diethanolamine and added into the CB-filled NR/CR blends as a rubber additive. The ALK loadings were 0.0, 1.0, 3.0, 5.0 and 7.0 phr. It was found that the ALK exhibited shorter scorch and cure times and higher elongation at break of the CB-filled NR/CR blends. The ALK also exhibited higher torque differences, tensile modulus and tensile strength up to 5.0 phr of ALK and then decreased with further increases in the ALK loading. The swelling test proved that the 5.0 phr loading of ALK caused the highest degree in crosslink density of the CB-filled NR/CR blends.


2015 ◽  
Vol 1107 ◽  
pp. 113-118
Author(s):  
Ahmad Kifli Che Aziz ◽  
Teku Zakwan Zaeimoedin ◽  
Mazlina Mustafa Kamal

The challenges of using Epoxidised Natural Rubber (ENR) in truck tyre tread are to achieve good cure reversion resistant and physical properties especially on abrasion resistance towards long vulcanization time. The objectives of the project are to study the effects of vulcanization additive on cure characteristics and physical properties of silica filled ENR compound. In this work, a variation of curing systems were employed and a standard carbon black filled Natural Rubber/Butadiene Rubber (NR/BR) compound as a comparison. Greater reversion resistance and physical properties were observed with inclusion of vulcanization additive in the silica compound as compared to compound containing any. The abrasion resistance on the hand improved in spite of long vulcanisation time which commonly practices in truck tyre manufacturing.Keywords: ENR, silica, vulcanization additive, cure reversion, abrasion resistance


2015 ◽  
Vol 815 ◽  
pp. 44-48
Author(s):  
M.H. Fatin ◽  
N.Z. Noriman ◽  
Kamarudin Husin ◽  
M.Z. Salihin ◽  
N.R. Munirah ◽  
...  

The potential of activated carbon as a filler in rubber compound has been reviewed .Cure characteristics and physical properties ofImperataCylindricaactivated carbon filled natural rubber of Standard Malaysian Rubber (SMR L) were studied. SMR L was used as the elastomer and the composition of filler loading were varied from 0-50 parts per hundred rubber (phr). A semi-efficient vulcanization system was used throughout the study. The cure characteristics of the rubber compound was determined by using rheometer. The samples of hardness and resilience were measured by durometer shore A and Wallace Dunlop Tripsometer. Cure characteristics showed that cure time, t90and scorch time,t2increased as increased filler loading which indicate poor interaction between rubber and filler which slow down the vulcanization time. Minimum torque,MLand maximum torque,MHincreased as increased filler loading due to the low processability of the SMR L compounds. Crosslink density and hardness exhibit increment as increased filler loading due to increase rigidity of the SMR L compounds. The resilience will decrease correspondingly as increased in rigidity of the compounds.


2011 ◽  
Vol 264-265 ◽  
pp. 646-651 ◽  
Author(s):  
Wittawat Wongsorat ◽  
Nitinat Suppakarn ◽  
Kasama Jarukumjorn

Natural rubber (NR) was reinforced with three types of filler: carbon black, calcium carbonate, and sisal fiber. NR composites were prepared on a two-roll mill. Filler content was 20 phr. Mechanical properties and cure characteristics of NR composites were studied. All NR composites had higher maximum torque than NR. NR filled with carbon black showed the highest maximum torque. However, scorch time and cure time of the NR composites were not much affected by filler types. In addition, influence of fiber treatment (alkalization) on mechanical properties and cure characteristics of sisal fiber-NR composites was investigated. Alkali treated sisal fiber-NR composite exhibited higher tensile properties and hardness than untreated sisal fiber- NR composite due to improved adhesion between the fiber and NR matrix. Moreover, alkali treated sisal fiber-NR composite had superior specific modulus and strength than NR composites filled with carbon black and calcium carbonate.


2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Dosu Malomo ◽  
Abdulhakeem D Olasupo ◽  
Abayomi M Adesigbin ◽  
Owen Egharevba ◽  
Sulaiman O Adewuyi ◽  
...  

Palm kernel shell was activated using chemical activation of H3PO4 and KOH. Various amounts of activated palm kernel shell (APKS) couple with carbon black (CB) and other conventional ingredients were used to produce natural rubber vulcanizates (NR vulcanizates). The NR vulcanizates were compounded on a two-row mill and tested for its physico-mechanical properties. The results for characterization of physicochemical properties carried out on APKS  were ash content (2.06%), moisture content (8.06%), %carbon (54.41%), particle size (4.00, 3.35, 2.00, 1.18mm), bulk density (0.62g/ml) and pH (5.3).The results show significant values for all, the moisture and ash content were within the recommended standard of ASTM (3-10max) and (< or =8) respectively. The filler loading concentrations CB/APKS were labeled as mixes 1 to 7. The composition of CB/APKS filler loading ratios were 30:0, 25:5, 20:10, 15:15, 10:20, 5:25, and 0:30 samples 1,2,3,4,5,6 and 7 respectively. Results obtained showed that CB/APKS filled vulcanizates exhibited improvement in the physico-mechanical properties investigated. The results obtained for CB/APKS across the samples filler loading shows that CB composition possess higher UTS, EB and rubber fatigue test while APKS filler loading composition exhibited higher hardness and young modulus. Abrasion resistance was excellent for both CB and APKS filler loading composition.Keywords: Activated Palm Kernel Shell, filler, carbon black, Chemical Activation, Natural Rubber.


1949 ◽  
Vol 22 (3) ◽  
pp. 812-819 ◽  
Author(s):  
N. L. Catton ◽  
D. C. Thompson

Abstract Reinforcement of elastomers with fillers has generally been measured by physical properties, such as tension stress-strain, tear resistance, hardness, and compression modulus. To a more limited extent, swelling in solvents has been recognized as associated with reinforcement. In natural-rubber vulcanizates it has been demonstrated that reinforcing fillers impart greater resistance to solvents and oils than do nonreinforcing types. Addition of the latter gives only the reduction in swelling attributable to elastomer dilution. In the case of Neoprene vulcanizates, Catton and Fraser reported that fillers function only as elastomer diluents and that those fillers commonly considered as of the reinforcing type impart no greater resistance to solvents than the nonreinforcing type. More recently, however, Buist and Mottram, in describing the effects of carbon blacks on the physical properties of natural rubber and Neoprene, reported that with both of these elastomers compounds containing thermal type carbon black gave slightly greater swelling in benzene than compounds containing equal loadings of other types of carbon black. With Neoprene, they reported good correlation between moduli and swelling characteristics.


2014 ◽  
Vol 974 ◽  
pp. 195-198
Author(s):  
Teku Zakwan Zaeimoedin ◽  
Mazlina Mustapha Kamal

Rheological studies of polymers are of great importance in optimizing the processing conditions and in designing processing equipments like injection molding machines, extruders, and dies required for various products. Melt rheological studies give us valuable viscosity data that will be helpful in optimizing the processing conditions. Parameters like melt viscosity as a function of shear rate or shear stress and temperature have become more and more important. Previous study indicated that the flow behaviour of the compound depends on the filler loading. Lesser elastic torque was found with compound containing lower filler content as compared to higher filler content. In this work, effect of dual filler, based on Carbon Black / Silica filled Epoxidised Natural Rubber (ENR) compound was investigated. A total of 80phr of filler content based on passenger tyre tread formulation was used in the experiment. The compounds were prepared by melt mixing in tangential type of an internal mixer. The rheological and the processability properties of the compounds were determined using three different testing instruments namely Capillary Rheometer, Mooney viscometer and Rubber Process Analyzer (RPA). A variation of shear rates (ranging from low to high) was performed, in order to better reflect the actual processing condition in rubber manufacturing. It was found that ENR mix with ratio silica to carbon black 70:10 exhibited the best flow behaviour and processability properties as compared to control and other mixes.


2010 ◽  
Vol 16 (2) ◽  
pp. 149-156 ◽  
Author(s):  
L.O. Ekebafe ◽  
J.E. Imanah ◽  
F.E. Okieimen

Samples of rubber seed shells were carbonized at varying temperatures (100, 200, 300, 400, 500, 600, 700, 800?C) for three hours each and sieved through 150?m screen. The portion of the rubber seed shell carbon that passed through the screen was characterized in terms of loss on ignition, surface area, moisture content, pH, bulk density, and metal content and used in compounding natural rubber. The characterization shows that the pH, conductivity, loss on ignition and the surface area increases as the heating temperature increases, unlike the bulk density which decreases. The compound mixes were cured using efficient vulcanization system. Cure characteristics and physico-mechanical properties of the vulcanisates were measured as a function of filler loading along with that of N330 carbon-black filled natural rubber vulcanisate. The results of the cure characteristics showed that the cure times, scorch times and the torque gradually increased, with increasing filler content for rubber seed shell carbon-filled natural rubber, with filler obtained at carbonizing temperature of 600?C tending to show optimum cure indices. The physico-mechanical properties of the vulcanisates increase with filler loading. The reinforcing potential of the carbonized rubber seed shell carbon was found to increase markedly for the filler obtained at the temperature range 500-600?C and then decrease with further increase in temperature.


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