Abstract: Silicone > Natural rubber. Key words:
Abstract:Inthe present time the entire world is concerned about the impact of conditioncontamination and the emissions from vehicle as a result of utilization ofpetroleum product is considered as a noteworthy commitment to it. Biodiesel isturned out to be the best trade for diesel as a result of their excellenteco-friendly properties. Eventhough the biodieselis considered as a better fuel than the fossil fuel, the automobile sector isnot ready to accept biodiesel because of less research related to compatibilityof materials with the biodiesel. This lags in the implementation of completelybiodiesel engine in automobiles.
This research work is mainlyfocused on the experimental investigation to study the effect of biodiesel onelastomeric materials used in automobiles and to suggest suitable material inthat field which is having higher compatibility with the biodiesel. Themethodology involvesimmersing the elastomeric materials like NBR, CR, EPDM,Silicone and Natural Rubber into the biodiesel and evaluating mechanicalbehaviors immersed at 250hrs. The experiments shows that the suitability of elastomers for biodiesel is NBR > CR > EPDM >Silicone > Natural rubber. Key words: WCObiodiesel, Elastomers, NBR, CR, EPDM, Silicone, Natural rubber, immersion tests. 1.
Introduction: The issues of fossil fuel depletion andenvironmental degradation are driving the search for the alternative fuels. Onesuch fuel is biodiesel, another option to diesel fuel created bytransesterification of vegetable oils or animal fats. It offers property nearthat of diesel fuel and has no sulfur and no aromatics. In diesel engine, fuelcomes into contact with a wide assortment of materials. Material compatibilityin biodiesel may not be quite the same as that in diesel. diesel is a blend ofhydrocarbons, while biodiesel is a blend of unsaturated fat esters. Thesimilarity of seal, gaskets, hose materials ordinarily utilized as a part ofcar fuel frameworks utilizing regular diesel fuel has for quite some time beenset up. Elastomers are essentially complexblend of polar and non-polar substances including polymers, fillers, oil,plasticizer, stabilizers, curing operators, cell reinforcements, antizonantsand preparing helps.
When it is submerged in a dissolvable, the elastomerlattice tends to swell. Swelling of EPDM, SR, CR and NBR upon presentation tofuel can be ascribed to the assimilation of dissolvable and unwinding ofpolymer chains. Be that as it may, there issubstantially less data accessible on the similarity of fuel frameworkelastomers with biodiesel especially Waste Cooked Oil (WCO) biodiesel. It hasbeen accounted for that degradation of specific elastomers is one of theprinciple issues identified with material compatibility in biodiesel. From theliterature it is clear that the impact of methyl yester and diesel blends onthe elasticity, lengthening, hardness, and swelling of a few basic elastomersdemonstrates different outcomes in view of their exploratory strategies. As thematerial will more exposure with fuel leads to higher swell because of theextraction of soluble components of elastomer. Irrespectiveof such impacts, a restricted however unequivocal part is generally ascribed todescribe the similarity of various elastomers in biodiesel.
The presentexamination plans to research the effect of Waste Cooked Oil (WCO) biodiesel onthe degradation value of Nitrile Rubber (NBR), Chloroprene Rubber (CR), EPDM,Silicone Rubber and Natural Rubber and to propose the perfect material amongthem. 2.Experimental set up: The compatibility of various elastomeric materialsviz, Nitrile Rubber (NBR), Chloroprene Rubber (CBR), EPDM, Silicone and NaturalRubber with Waste Cooked Oil (WCO) biodiesel was evaluated by conductingimmersion in B0 (diesel), B20 (20% biodiesel in diesel), B50 (half biodiesel indiesel), B100 (biodiesel) at room temperature (32 0C) for 250 h. Atthe end of immersion, degradation of various elastomers was portrayed byestimating changes in weight, volume, hardness and elongation. Changes in weightwere estimated by adjust with 3 decimal accuracy. The hardness estimation ofthe materials was meausred utilizing “Shore A” Hardness analyzer.
Allthese tests were conducted before and after immersion test. 3. Results and discussions:a) % Changes in Volume:Fig. 1 demonstrates the change inVolume of the elastomers upon exposure with various blends of biodiesel withdiesel fuel.
Volume for Nitrile Rubber (NBR), Chloroprene Rubber (CR) and NaturalRubber increases with expanding the concentration of biodiesel, while for EPDMand Silicone Rubber displays reduced volume with increments in biodiesel concentration. Figure 1. Change in Volume of elastomerfor different biodiesel blends for 250hrs.Elastomers appear to swell inbiodiesel through responses with the polymer backbone and cross-linkingframework, or by responses with the filler system. This results that biodieseland its blends cause a grater swelling of CR, NBR and Natural rubber contrastedand that caused by diesel. Then again, EPDM and Silicone swelled to a morenoteworthy degree in diesel contrasted and that in biodiesel and its blends.
NBR is a complex group ofunsaturated copolymers of ACN and butadiene while CR alludes to polymers of2-chloro-1,3-butadiene with one polymerizable monomers. The more noteworthy theacrylonitrile content in NBR, the less the swell in fuels as it can guaranteeexpanded cross-linking in the polymer spine 1.The principle behind the swell ofthe elastomer is “like – disintegrates – like.” There is a general ruledepicting the way that polar substances will probably break down in polarsolvents and nonpolar substances will probably break up in non-polar solvents2. For polar dissolvable, the positive ends of the molecules will draw in thenegative ends of the solute atoms and accordingly makes an intermolecular powerknown as dipo – leedipole association.
The level of dipo – leedipolecooperation in biodiesel for solute is by all accounts higher when contrastedwith that in diesel in light of its extra exceptional synthetic distinctionemerging from the expanded extremity of esters 4. Subsequently, swelling ofsame elastomer material is similarly higher in biodiesel than that in dieselfuel. In the event that the dissolvable polymer collaborations are morepredominant than polymer connections, greatest swelling can be obtained 3. b) % Changes inweight: Figure 2. Change in Volume of elastomerfor different biodiesel blends for 250hrs. It is seen that the as changes in weight for both CRand NBR are higher in biodiesel when differ strikingly with that in diesel.Then again, EPDM, SR and Natural Rubber are less perfect with biodiesel.
Thiscan be attributed to the higher extremity of ester segments in biodiesel whichenables the more polar elastomers to disintegrate to dissolve to a greaterextent. Moreover,all particles additionally have weak intermolecular forces called LondonDispersion forces by which positive cores of the solute molecule atoms willpull in the negative electrons of the dissolvable atom molecules 2. Thisgives the non-polar dissolvable more noteworthy capacity to solvate the soluteparticles. The increase in weight came about as the degree of more liquidabsorption when contrasted with the extraction solvent segments from elastomer.The expansion in weight can be ascribed to the degree of higher fluidassimilation when contrasted with the extraction of dissolvable segments fromelastomer. Then again, the causes of lightly reduced weight for CR and NBR canbe attributed to the absorption of lighter component like diesel or biodieseland in the meantime, disintegration of dissolvable parts, for example,plasticizers, stabilizers or added substances from the elastomers 1.
c) % Changes inElongation: Figure 3. Change in Length of elastomerfor different biodiesel blends for 250hrs. Figure 3.demonstrates the changesin Elongation of the elastomers upon immense in various biodiesel and theirblends. Elongation for Nitrile elastic (NBR) and Chloroprene Rubber (CR) increasedwith concentration of biodiesel and displays lessened length if there shouldarise an occurrence of diesel. While for EPDM and Silicone Rubber displaysdiminish in elongation with increments in biodiesel concentration while NaturalRubber shows higher stretching for B20 and B50 blends and bring down extensionfor pure biodiesel contrasted and diesel. Notwithstanding, higher change inlength was seen in case of biodiesel.
This maybe because of higher absorption ofbiodiesel in elastomer. d) % Changes inHardness ( Shore A): Figure 4. Change in Hardness ofelastomer for different biodiesel blends for 250hrs. From the figure 4 itis clear that the shore A hardness value of elastomeric materials willdiminishes when presented to biodiesel. Likewise hardness of CR and NBR inbiodiesel diminishes more contrasted with that for diesel, though the hardnessvalue for EPDM, Silicone and Natural Rubber shows higher than that of thediesel. This may demonstrate higher disappearing of crosslinking forChloroprene Rubber (CR) after immersion into biodiesel.
For elastomers,carbon dark & silica fillers can serve to enhance the hardness. Theexpansion of curing specialists and quickening agents cause cross-connectingbetween the polymer chains or spine. It is this system that cross-connects to agreat extent, decides these physical properties. Upon exposure of variouselastomers into biodiesel, these cross-connecting agents or filler appear torespond with components of biodiesel and accordingly fall apart the physical& mechanical properties. Not at all like NBRand CR; EPDM and Silicone does not demonstrate any critical auxiliary changeupon exposure to biodiesel. All representing functional groups remain intacteven after long immersion into biodiesel.
4. Conclusions: The accompanyingconclusions can be drawn from this investigation as 1. The weight andvolume for NBR, CR and Natural Rubber are expanded with increasing theconcentration of biodiesel while for EPDM and Silicone Rubber they diminishwith biodiesel concentration.
2. After immersioninto biodiesel it is found that the elongation and hardness were significantlyreduced for both EPDM and silicone while negligible changes were found forNatural Rubber, though CR and NBR demonstrates unfavorable with thesematerials. 3. Biodieselcontaining ester has more carboxylic gatherings when contrasted with those inpetrodiesel. Elastomers are appeared to be debased more by those carboxylicpolar groups of biodiesel.
4.Theobtained results from this work can assure consumer that the compatibility ofelastomers for biodiesel is in the preference like NBR > CR > EPDM >Silicone > Natural rubber.