We are discussing the module 8 of the organicchemical technology track, which is about the polymer, elastomere and synthetic fibreand in the previous 3 castigates we discussed about the nylons. We discussed about the nylon6, nylon 66, polyester and then the acrylic staple and how the development that has takingplace in these sectors and how it has played important role in rally the synthetic fibredemand of the growing population. Now today, I will be considered by about theviscose rayon that is acetate rayon and cuprammonium rayon, which is one of the very importantsector in case of synthetic fiber and because of its very good quality and the appearancelike the silk rayon that has been in use and for only thing that in now the differencebecause in case of the all the other synthetic fibre, which is we call it the true syntheticfibre or the manmade fibre that is the nylon or the polyester or the acrylic substance whichthe raw material major raw material is from the petrochemical fibre, here rayons are basedon the cellulose raw material, high quality of cellulose having alpha cellulose, loosesemi cellulose and the pentagon.So, these are the some of the basic difference, herewe are dependent upon the natural raw material. So, the coverage of the lecture that willbe on the introduction, properties of the viscose rayon, Indian capacity of the viscoserayon, application of the viscose rayon, then the process details of the viscose rayon manufacture.Then we will be discussing about the acetate rayon and the cuprammonium rayon. Althoughthe amount of the total capacity if you discover the product prudent it is more in case ofthe, something much, in case of the viscose rayon than the acetate and cuprammonium rayon, but, some of the other raw material certainly that will be from the petrochemical.This is you can see the viscose fibre howit looks like and it is just like woollen material or the acrylic material you can sayand the brightness you can see the brightness of the fabric likewise and because of the moreand more convenience “weve gotta” in case of the viscose now the use of the viscose inthe textile that is increasing day by day. This is also is the acetate fibre which was, “hes also” the silk like form we are having. So, the rayon is made from cellulose derivedfrom natural happen material, peculiarly the timber we are using now, wood pulp we areusing in case of the rayon making.Some of the common rayons are the viscose rayonacetate rayon and the cuprammonium rayon. Amongst the various rayon, viscose rayon isthe most commonly commercially construct rayon and find wide employment in textile, tire cord manufacture, because as I “ve told you” earlier too that the tire rope that has beenone of the major consumer of the synthetic staple but, with the coming of the other fibrethe petrochemical based synthetic fabric now, more and more polyester or it was possible to the polypropylene fibre or it may be the nylon that is going in tire cord industry. But, the importancedefinitely because the viscose that was available earlier than the coming of the your thesenylons or it was possible to the acrylic fiber. So, the importance of ensuring that the viscose rayon is bothin the oven and non oven. Many type of the viscose rayon and thatwe are having the regular rayon, high perversity rayon, high rain modulus rayon, kindled retardantrayon, super adsorbent rayon.Viscose rayon has a silk aesthetic with superbdrape and the feel and retains its rich gorgeous emblazon, which I evidenced you in the sketch, the picture of the viscose fiber brilliant colouring. It has high-pitched moisture absorbency similarto cotton and this is the reason why we are consuming more and more viscose compositionblend along with the it was possible to the acrylic fabric or it may be the polyester, becausethe cost of the viscose is less than the cotton, breathable, comfortable to wear and easilydried, because in the earlier stages of the coming of the manmade fibre dying was alsoa problem for synthetic fibre, extremely the polyester and the nylon and the plenty ofthe improvement that took place in case of the dye construct also and so the dyingthat was the more easier in case of the synthetic substance with the coming of the brand-new produce ofthe pigments. So, the in case of the viscose rayon, it iscomfortable soft skin and has moderate, because that was the softness that was your problemin case of the polyester when it came into the market because, most of the textile 100 percent polyester suitings 100 percent polyester shirts were there and so, that wasnot comfortable.So, one of the advantage in case of the viscose and now we will seein market the very soft textile fabrics are there which is because of the viscoserayon, the soft scalp and has moderate dry forte and low-grade abrasion fighting and nostatic build up, as in case of the other polyester and the nylon is there, moderate resistanceto acid and alkali, excess flammable, but, this is the one of the disadvantage.Thermal dimension is poor and loses strong about 9 stage chars and decomposes at sothe melting point, this was the reason why the from the viscose to nylons or the polyesterin the tire line industry that was because, what we need in case of the tire rope industryhigher melting point and that was the reason because in case of the nylon and polyesteror the acrylic that is we are having plus 230 freezing point or the sticking point.So, that is the one of the drawback in case of the viscose rayon that is the low-spirited meltingpoint. Tenacity straddles between 2 level 0 to 2 point6 gram per cave now and dry and 1 extent 0 to 1 stage 5 lair here when wet. It has poorcrease improvement, because this is the 1 of their own problems even in case of the cotton but, still further the wrinkle is concerned ironing property is there it is better in case of the polyesteror in case of the nylon but, in case of the viscose and the cotton this the crease problemis there in case when you are using in case of the textile.So, it has poor crease improvement and seam retention in comparison to the polyester becauseof the low-grade freezing point lower work in the tire rope that is there.But, earlierwhen it was not available the people were applying the viscose rayon also but, the yousee the now the velocity of the vehicles that is increasing and so, the temperature riseis there and so, the work requires the more higher temperatures high-pitched melting point material for the tire cordindustry and so, that was the shifting from the viscose rayon to your polyester or thenylons. These are the various points of the viscoserayon types of the rayon: regular high-pitched moisture modulus, high perversity, micro materials, Tencelrayon the lyocell these are the some of the brand name likewise that is these. These are the some of the major producersof the rayon. 1 is the century rayon that is because; most of these companies are bythe Birla group because they are pioneer in too the working paper acquiring. So, century rayon theyare having the 1 unit is at Kalyan, another the mushy they are making at the century pulpand paper and that lends Kashipur that they are having 1 flower. Grasim industry they areheavier polyfibre, these are the other which are representing the rayon do paste. Kesoram rayonthey are fixing rayon, Indian rayon, national rayon, Baroda rayon and so this is the domesticdemand of the viscose So, the an applicant for the viscose rayon; yarn, then embroidery, chenille, cord , novelty yarn.The fabric; crepe, garadines, suiting, fasten, outwear fibers and rowing of the coats and outwear. So, these are the in case ofthe fabric we are using even the liner character is there were more your softness that is required.So, ordering one of the purposes of the hairs we are having the viscose fabric. Apparel are full-dress, blouses, saris, coats, lingerie, liners, hats millinery, slacks, sports shirts, sportswear, dres tiesand the drudgery cloth. So, these are the some of the clothe thatwe are obligating from the domestic textiles berthed spreads, bed sheets, coverings, shrouds, draperies, slip reports, table invests and the hosiery. In Industrial textiles, high-pitched perseverance rayonis used as reinforcement to mechanical rubber goods, tires, conveyor so, here actually therequirement that is the high-pitched diligence rayon, so the tires, conveyor, belts, hoses, applicationwithin the aerospace agriculture textiles industry and then the braided ropes and thetapes.Miscellaneous uses; that may be the in the sausage casing, cellophane and thenthe feminine hygiene. What are the raw materials you envision? Here yousee the major raw material which we are using for the meeting of, whether it is viscose rayonor the acetate rayon that is the cellulose. Then the caustic soda, carbon disulphide, sulphuric acid, titanium oxide to delustre the wool and then the sodium sulphide, sodiumsulphite, sodium hypochlorite these are the some of the other actually the raw materials. 1 of the another important raw material that we are using the carbon disulphide in caseof the viscose rayon, acid and acetate anhyde in case of the other rayons that we are using.This is the requirement especially in case of per ton of the rayon fibre of the variousraw material pulp, NaOH, H2SO4, carbon disulphide, zinc sulphate, because now the spinning sothat is the spinning bar that we are doing by the way it is.This is called the regenerationwet revolving that is being done in case of the viscose rayon and other rayons. These are the various steps involved in caseof the viscose rayon that is, the first step that is the production of the dissolving, because the pulp which we are using, because we are using the paste for attaining the paperand the story periodical, here the paste which we are using for the obliging of the rayon thatwe call the dissolving grade pulp for high alpha cellulose because what is happeningeven where 1 of the process which we are using in case of your treating with the causticsoda, so, alpha cellulose, high alpha cellulose material that is required and so that is thebeta and gamma cellulose which present that we are removing.So, the divest pressing, shredding aging, xanthation ripening, filtering degassing, extruding through spinneret and acid soak paint, soaking and cutting.So these arethe steps. And easy gradations we will be discussing in detailbecause there is importance of the each and every step in the manufacture of the viscoserayon because that will affect the quality of the viscose that we are preparing. First thingthat is the pulp, which we are getting, what will be the source of the cellulose. Celluloseused for the manufacture of the viscose rayon. So, rayon tier paste we call it that we areusing. So, rayon score paste or melting mushy is the source of the cellulose. Dissolvinggrade pulp is made from the timber, predominantly it is the wood pulp that is preferred and especiallythe softwood but, some eucalyptus because eucalyptus having the very good quality ofthe mushy so that has been also worked. So, terminating point mushy is made from the wood.The pulp should have high-pitched cellulose low-toned hemicellulose with the uniform molecular weight distribution.Special bleaching cycle, because you examine the pile of the detoriation in the qualityand the strength of the pulp is there during the bleaching when we are using the conventionalbleaching of the chlorine or chlorine dioxide or the hypo chloride bleaching.Here, we needthis some of the other revised bleaching strings for the realise of the rayon gradepulp and 1 of them is the enzymatic bleaching. Too, the oxygen chlorine dioxide or the oxygendelignification that may be there or it may be polysulphide pulping. So, different typeof the pulping manages also there but, bleaching we will have take care so, that the minimumdamage is there and at the same time the selective removal of the pentagon is also there whenyou are using the enzymes. So, this is the basic requirement in caseof the your rayon point mushy and you appreciate the different, it is not the same process whichyou are meeting from the broad process is same which well spawning the pulp for the papermaking but, now the special aspect of the rayon grade mushy that will be required formaking with the high alpha cellulose hemicelluloses pentagon all those that should be minimal.So, the first step in case of the manufactureof the viscose rayon is the steeping process. This involve the pulp sheets are placed insteeping chamber and responded with 18 to 20 percent NaOH at 20 to 22 degree centigradefor about 1 to 4 hour, because you discover the goals and objectives why if you receive the definition of thealpha cellulose beta and gamma cellulose, so, the alpha beta and gamma cellulose whenwe are treating with the 17 pitch 5 percent of the NaOH, so, alpha cellulose that remainsas such and the beta and gamma cellulose they dissolve. So, that is the reason of the keepingthe 18 to 20 percentage NaOH.Then what is the purpose? This is 1 purposeto break the intermolecular ligaments of the cellulose to increase the solubility of the cellulosexanthate because eventually, we are treating with the carbon disulphide for xanthation.So, to convert the cellulose into alkali cellulose because, this alkali cellulose that furtherwe are using. The grow cellulose substance, because the swelling of the material and so, the betteractually your reaction of the carbon disulphide that will be there, to dissolve the low-spirited molecularweight hemi cellulose. Then, the next step in case of the viscoserayon create is the pressing constituent. This is done to remove the excess liquid whichis there and so, finally, after the pressing the your cellulose that will go to the shadingand the grey smidgen that we will be getting, the alkali cellulose obtained since pressingare lead to shredder at about 20 degree centigrade for 90 to 120 minutes.This involves shreddingof the pressing sheet, which we are getting from the previous pace, to produce white crumb, which is fluffy which give breath to penetrate effectively inside.So, because if you are taking as such the pulp if it is not fluffy then the reactionof, xanthation reaction which we are using in ozone-depleting substances places that will be not effective.So, this was shredding and the stirring of the lily-white shred that is also very important stepin case of the viscose rayon manufacture. Then it comes the aging. After shredding thewhite crumb are aged to bring down degree of the polymerization. This involves agingof the shred through exposure of the lily-white smidgen to oxygen. It assists in maintaining theproper viscosity. This is the next step after your shredding. This is the main reactionwhich is taking place in case of the viscose rayon and that is one of the very importantreactions that is xanthation where the we are reacting with the carbon disulphide afteraging. The soda cellulose slivers are fed into airtight rotating churns, these are also churning process. The process involves treatment ofthe lily-white shred with carbon disulphide under controlled condition at 20 to 30 degree centigradeto form a cellulose xanthate.This is called the amber sliver, which we are getting andthis is going for the further processing to get the viscose rayon. The yellow smidgen isdissolved in caustic soda to way viscose. Then the next step in case of the viscoserayon is the ripening, filtering and deaeration. The process involves ripening of the viscoseby impeding it for 4 to five days, because now the low temperature is there and so, thatis also 1 of the important requirement in case of the viscose produce, by keepingthis various forms of the fibers being spawned. Ripeness measured by the Hotteen number, thatis 1 of the number of the ripeness is there. After ripening the ripen viscose is filteredand degassing, degassing is a further step there to remove the air bubbles which is there.Now the let us discuss the above spinning of theviscose, because as I “ve told you” earlier here what are doing? We are doing this bed spinningand this is also called the regenerated cell. So, rotating of the viscose is done by wetspinning by passing through spinnerette in acid in battery-acid shower ensuing in formation ofrayon fibre. This is your bath composition. Sulphuric acid, sodium sulphate, glucose, zinc sulphate and liquid. This is the composition of your bathin case of the spinning soap which we announced it the sodium sulphate precipitates sodiumcellulose xanthate into filament form. This is why sodium sulphate that has been addedand acid proselytizes it into cellulose. Zinc sulphate presents added forte. Further processinginvolves, after this rayon is modelled or the wool is formed so, what is the next step? Further process involved cleansing, desulphurising, bleaching, situation and drying.Drawing And cutting; Drawing is the processof stretching the rayon wire which is straighten out the fibres, because this is1 of the very drawing in all the cases of the substance reaping is very important in togive fortitude to the yarn. The continual recital is cut into for producing staple fibres. What are the various variables involved incase of the viscose rayon? The spinning process, temperature and composition of the bathroom, speedof the coagulation, length of the immersion, fast of the spinning, extend contributed tothe fiber, because the that is as I told you the stretch contributed to the filament thatis also very important. So these are the some of the parameters which are affecting yourspinning process. This is the reaction that is taking placeand the cellulose with NaOH. Then it is the sodium cellulose that you are getting andafter reacting with the carbon disulphide, cellulose xanthate and this cellulose xanthateagain we are getting the renovated cellulose and in the form of the yarn. So, this is the process which I discussedabout the manufacture of the viscose rayon.This cellulose expanses in the form of the sheetswe are getting the paste and that expanse or the pulp membrane or cellulose sheet, whateveryou say it, this is going to the steeping and press section.Then the shredder alkali cellulose aging tank, xanthation reaction where the for regulatingthe dissolving barrel filtration, ripening, deaeration, that is removal of the breeze bubbleand then the viscose inventing. These were the actually the steps which you discussedin detail earlier and so, this is the process flow diagram and then the viscose spinningthat will go to spinning bath where the viscose fibre that will be getting. This is aboutyour, it is going to the coagulating bath that is the makeup tank where H2SO4 and Na2SO4that we are adding. So, this is the washing, desulphurisation, the bleaching and the conditioningand drawing. These are the some of the other steps that are involved.Now tell us come to this. This was about theviscose rayon. You encounter, the viscose rayon, as I “ve told you”, that is 1 of the very importantpart of synthetic fibre which we are using in our everyday lives. Another type of the rayonwhich was produced earlier that was the acetate rayon and this is the really expression silklike form. It was like the synthetic silk we used to call it and we are callingthe acetate rayon. Acetate rayon is the other cellulose basedmanmade fibre and has silk like appearing. The raw material is cellulose, acetic acid, acetic anhydride. Again the acetic acid or acetic anhydride can be from the booze routeor it may be from the petrochemical route. Here, the purified cotton linters, where thecotton linters or cellulosic is a cellulose, cellulosic information both the cotton lintersthat is the fibre is more stronger than the cellulose, is fed to the acetylator containingacetic anhydride and acetic acid and converged sulphuric acetylation is carried out at 25 to 30 degree centigrade.This is the reaction combine called the aciddope is allowed for ripening for about 10 to 20 hours. During ripening that is the conversionof the acetate radicals makes home. After this, the potpourrus is diluted with water with continuousstirring. During the process flakes acetate rayon isprecipitated which is baked and sent to the spinning bath where dry spinning of the acetaterayon makes residence by dissolving in the solvent and passing through spinneretted.So, “thats really not” the degenerated as in case of the viscose rayon we are doing the wetspinning.Here, in case of the acetate rayon where we are having dry spinning also. Thesolvent is molten by hot air during this spinning process, where the because the itwill pass through the number of folds are there in spinnerette and the ceaseless rayonthat will be getting and the drying of the objective of eliminating the your solvent that will be there. Activation with the acetic acid; the processinvolves steeping of the purified cotton acetic acid which concludes swelling and impels the cellulosemore reactive. So, that was the purpose of the activation with the acetic battery-acid acetylation, already we discussed this part. The pretreated cotton and the acetic acidis then acetated with the excess acetic battery-acid, acetic anhydride, with sulphuric acid to promotethe reaction. So, 1 one of the purposes of the purified cellulose, 3 part of the acetic anhydride and 5 partof the acetic battery-acid, that is the combination. Sulphuric battery-acids as catalyst 0 top 1 constituent, reaction is exothermic, the temperature is around 20 degree centigrade for first hourand 25 to 30 degree centigrade for the next 7 to 8 hours. Then the hydrolysis of the triacetate; thetriacetate structure is hydrolysed to convert triacetate to diacetate. The resultant potpourrus is pouredin ocean to precipitate the cellulose acetate fibre with different degrees of polymerization 350 to 400. Assets of the acetate rayon; perseverance 1 pitch 4 gram per denser, melting point 230 degree centigrade and decompose when defrosted freely, soluble in acetone methyl, ethylketone, methyl acetate, ethyl acetone, chloroform and the ethylene chloride So, this is the spinning, once I told youthis rotating is disbanded in the acetone that we are using as a solvent and then thefilter deaerated and elapsed through the spinnerette in hot air environment, which vaporizes thesolvent.So, that is the spinning process dry spinning process that we are using. So, low cost and availability here actually as we are using huge amount of the acetic acidand Acetic anhydride, so, the some of the inexpensive production that will depend uponthe low cost and availability of the acetic battery-acid and acetic anhydride recovery of theacetic acid. That is very important in case of the polyester, also, recovery of the aceticacid that is very important. Now the recuperation of the acetone that we are using for the spinningthat is that has to be recovered effectively and economically.So, these are the some of the issues involved in case of the 1 of the major problem thathas been in case of the all the rayons, because we are using the forest raw material, meansthe timber for attaining of the paste. So, that is from the environment point of view andthe deforestation point of view. So, this is the process which I “ve told you” theacetic anhydride H2SO4, acetic acid and the mushy and the here acetylator. That is thecotton linter or the wood pulp that is going to the acetylation and then the it is goingaging, precipitation, centrifuging and cellulose acetate for spinning that is going when weare doing the cool spinning we are doing.This is the reaction that is taking placeduring the acetylation. Now, tell us come to another important class of the cellulosicbase rayon that is the cuprammonium rayon. Although the amount of acetate and cuprammoniumis much less than what you have in case of the viscose rayon but, these are the apartof this rayon some other rayons are also there which are made from the natural material, thatis just a galvinate staple, soyabeen staple so, all those things are also there. Let usdiscuss now the cuprammonium rayon. Cuprammonium is made from reaction of cellulosewith copper salt and ammonia. After bleaching cellulose is added to the ammonia solutionof copper sulphate ensuing in shaping of cuprammonium cellulose, which is spun intowater and the yarn is cleaned with acid to remove the vestiges of the ammonia and bone-dry. So, this is the method which we are usingfor the and if you read the here also the shredding and emptying, caustic digestion, sodium hypochloride for bleaching that we are adding and in case of this is the wood pulp the cottonlinter that is going.So, this is after the shredding because the more effective reactionsmay be there and so, the caustic absorption after the shredding that is been done. Mixingand resolution, filtration, revolving, bathing and baking, so, this is the process that weare using in case of the cuprammonium. So, this was the actually about the variousrayons and that we are manufacturing and as I told you in the beginning likewise the viscoserayon that has played very important role in meet the demand of the textile industry.And again now we are finding the trend in the market is to use the more viscose rayonand the various mergers of the polyester or the acro nitrate, because the cost point ofview and at the same time more comfort is there when you now have the viscose rayon.So, the one of the actually major issue that has been in case of your viscose rayon floras, all the viscose rayon flowers, because now which I forgot tell you, we are using hugeamount of the caustic soda and that caustic soda now most of the viscose rayon manufacturingthey are having their own caustic chlorine bush and earlier as you recognize, before comingof the tissue process, “theres only” the mercury cadre process that was being used in the makingof the caustic chlorine.So, in case of the all the bushes one of theanother issue that has been there, where to go? Where will be chlorine? So, chlorine handlingthat has been 1 of its most important because that has to be supplied somewhere because duringthe manufacture of the caustic. So, this was the 1 of the issue. Another issue in caseof the viscose rayon, the your environment point of view because you see in case of thecarbon disulphide that is highly toxic and the smell of the carbon disulphide that isthere in the embed. So, 1 of the major issue that has been in case of the viscose rayonis the chemical part of the chemical manufacturing section of the viscose rayon, because normallythey are having the in case of the any viscose rayon that will be 1 of the carbon disulphideunit, corrosive chlorine seed and then the lastly, the viscose rayon manufacturing.So, just like you make the case of that they are having the sheaths likewise the majority of members of nowthe caustic chlorine flora they have been converted to membrane corrosive chlorine plantbut, the question of the this chlorine that there.So, this is 1 of the factor which is affectingthe cost of the viscose too ..