Polymer is a immense molecule besides known as supermolecule composed of retroflexing structural units linked by chemical bonds of covalent.
Polymers are considered in the Fieldss of polymer natural philosophies, polymer scientific discipline and polymer chemical science. Natural Polymers ( from the Grecian poly intending “ many ” and meros intending “ parts ” ) are found in many signifiers such as horns of animate beings, tortoise shell, shellac ( from the lac beetle ) , rosin ( from pine trees ) , asphalt, and pitch from distillment of organic stuffs. One of the most utile of the natural polymers was gum elastic, obtained from the sap of the Hevea tree. ( Rubber was named by the chemist Joseph Priestley who found that a piece of coagulated latex gum was good for rubbing out pencil Markss on paper.
In Great Britain, erasers are still called “ gum elastics ” . ) Natural gum elastic had merely limited usage as it became brittle in the cold and melted when warmed. In 1839, Charles Goodyear discovered, through a lucky accident, that by heating the latex with S, the belongingss were changed doing the gum elastic more flexible and temperature stable. That procedure became known as vulcanisationAnother common name for many man-made polymers is plasticA which comes from the Greek word “ plastikos ” , suited for modeling or determining. Many objects in day-to-day usage from packing, wrapper, and edifice stuffs include half of all polymers synthesized. Other utilizations include fabrics, Television ‘s, Cadmium ‘s, cars, and many other all are made from polymers.
Get downing in 1811, Henri Braconnot did open uping work in derivative cellulose compounds, possibly the earliest of import work in polymer scientific discipline. The development of vulcanisation subsequently in the 19th century improved the lastingness of the natural polymer gum elastic, meaning the first popularized semi-synthetic polymer. In 1907, Leo Baekeland created the first wholly man-made polymer, Bakelite, by responding phenol and methanal at exactly controlled temperature and force per unit area. Bakelite was so publically introduced in 1909.
Its original usage was to do billiard balls. Rayon, the first man-made fibre was developed as a replacing for silk in 1911.Although many polymers were made in the undermentioned old ages, the engineering to mass bring forth them was non developed until World War II, when there was a demand to develop man-made gum elastic for tyres and other wartime applications and nylon for parachutes.
Since that clip, the polymer industry has grown and diversified into one of the fastest turning industries in the universe. Today, polymers are normally used in 1000s of merchandises as plastics, elastomers, coatings, and adhesives. They make up approximately 80 % of the organic chemical industry with merchandises produced at about 150 kilograms of polymers per individual yearly in the United States.
RUBBER, A Natural Polymer: :
Natural latex is found in the interior bark of many trees, particularly those found in Brazil and the Far East. The white gluey sap of workss such as silkweed and blowballs is besides a latex. Latex will turn into a rubbery mass within 12 hours after it is exposed to the air. The latex protects the tree or works by covering the lesion with a rubberlike stuff like a patch.
Natural gum elastic is a polymer of isoprene ( 2-methyl-1,3-butadiene, see Figure 1 ) in the signifier of folded polymeric ironss which are joined in a web construction and have a high grade of flexibleness ( See Figure 2 ) . Upon application of a emphasis to a gum elastic stuff, such as blowing up a balloon or stretching a gum elastic set, the polymer concatenation, which is indiscriminately oriented, undergoes bond rotary motions leting the concatenation to be extended or elongated ( See Figure 3 ) . The fact that the ironss are joined in a web allows for elastomeric recoverability since the cross-linked ironss can non irreversibly slide over one another.
The alterations in agreement are non constrained by concatenation rigidness due to crystallisation or high viscousness due to a glassy province.Since latex will solidify in air, a stabilizer is added to forestall polymerisation if the latex is to be stored or shipped in liquid signifier. The stabilizer is normally 0.
5 to 1 % ammonium hydroxide. When the ammonium hydroxide is removed by vaporization or by neutralisation, the latex will solidify into gum elastic.Figure 2: Conventional study of a typical Figure 3: Elastic distortionelastomeric web. of a gum elastic concatenation.
Make a Rubber Ball from Rubber Latex:
Wear safety goggles at all times in the research lab.When observing the olfactory property of the gum elastic latex, cup your manus and pennant the bluess toward you.
Make nontake a deep breath of the stuff.Make sure the gum elastic ball is submerged under H2O when squashing out the extra liquid toprevent it force outing onto anyone.
Rubber latexVinegarStiring rodPaper cupMeasuring devices
Measure 20 milliliter of gum elastic latex into a paper cup.Carefully, smell the stuff. Describe its olfactory property.Pour a few beads of latex onto the thenar of your manus. Spread it out utilizing yourfingure.
Observe any alterations that take topographic point.Add 20 milliliter of H2O to the latex in the cup and splash.Add 20 milliliter of acetum to the cup and stir the mixture.Remove the mass from the cup and stirring rod with your fingers. Carefullysquash the mass while rinsing it submerged. Form the mass into a ball byrepeatedly revolving it and squashing it.Dry the gum elastic with a paper towel.Drop the gum elastic on the floor and depict what happens.
BAKELITE, The First Synthetic Polymer:
Bakelite, a phenol-formaldehyde polymer, was the first wholly man-made plastic, foremost made by Leo Baekeland in 1907. Baekeland and an helper started their research in 1904 looking for a man-made replacement for shellac. Bakelite was commercially introduced in 1909. Bakelite was foremost used to do billiard balls, but, subsequently, was used to do shaped insularity, valve parts, boss, buttons, knife grips, many types of molded plastic containers for wirelesss and electronic instruments, and more.
Wear safety goggles at all times in the research labFormalin is an thorn to the tegument, eyes, and mucose membranes.Phenol is toxic via skin contact. It is listed as a carcinogen.Glacial acetic acid is an irritant and can do Burnss on contact.
Work under a goon and wear baseball mitts and protective vesture when workingwith these stuffs
Phenol-formaldehyde reaction mixture ( newly prepared solution should beavailable. The reaction mixture is made by blending 25 g 36-40 %methanal + 20 g phenol + 55 mL glacial acetic acid. )Hydrochloric acid, HCl, concentrated150-mL beakerstirring rod
Under a goon, step 25 milliliter of the phenol-formaldehyde reaction mixtureinto a 150-mL beaker. Put the beaker on a white paper towel.
Add 10 milliliter of concentrated hydrochloric acid, easy, with stirring.Add extra hydrochloric acid, dropwise, with stirring. ( You will necessitateabout 2 milliliters of HCl. ) As the polymerisation point is reached, a whiteprecipitate will organize and fade out. At the point where polymerisation begins,the white precipitate will non fade out.Continue to stir as the plastic signifiers and becomes pink in coloring material.Wash the plastic good before managing.Describe the belongingss of the plastic.
RAYON, The First Synthetic Fiber:
What may be considered as the first precursor to Rayon, Louis Marie Hilaire Bernigaut, Comte de Chardonnet worked on a procedure of bring forthing togss of an “ artifical silk ” made from collodion in 1884. Chardonnet ‘s silk was eventually marketed in 1891, but was short-lived after a immature lady ‘s ball gown when up in a whiff of fume after being touched by the lit cigar of her bodyguard. Charles F. Cross and Edward J. Bevan patened their expression for cellulose xanthate, a cellulose polymer, in 1892 and were shortly fabricating points of their new Viscoid. The first viscose yarn was made by Charles Topham Jr. and commericially produced in 1899. Rayon, made from regenerated cellulose in 1926, marketed by Du Pont, was eventually used as a replacing for silk.
Wear safety goggles at all times in the research lab.Ammonia exhausts are annoying eyes, and mucose membranes. Work in a well ventilatedcountry.
Copper ( II ) sulphate pentahydrate, CuSO4a‹…5 H2OAmmonia, NH3, concentratedSulfuric acid, H2SO4, 5 % solutionFilter paperFunnelsPlastic dropperStiring rod
Dissolve 5.0 g of Cu ( II ) sulphate pentahydrate in 25 milliliter of deionized H2O. Working under a goon, add concentrated ammonia solution dropwise, with stirring, toorganize a light bluish green Cu ( II ) hydrated oxide, Cu ( OH ) 2, precipitate persists. Let the precipitate to settle for a few proceedingss. The staying liquid should be light blue or colorless. If necessary, add an extra bead or two of the ammonia solution to look into for completeness of precipitation of the Cu ( II ) sulphate.
Avoid an surplus of ammonium hydroxide. Roll up the precipitate by gravitation filtration. Wash the solid with two 5 mL parts of cold H2O.Transfer the precipitate to a 150-mL beaker.
The filtrate can be discarded.Under a goon, add 25 milliliter of concentrated ammonia solution to the beaker. Srit to fade out thesolid.
Obtain two pieces of filter paper. Tear them into pieces and add them to the dark bluish copperammonia solution. Stir to fade out the filter paper.Obtain 100 milliliter of 5 % sulphuric acid in a 250-mL beaker.Fill a fictile dropper with the bluish cellulose-copper-ammonia solution. Put the tip of thedropper below the surface of the 5 % sulphuric acerb solution and force out its contents into the solution.Dark bluish togss will organize which will easy decolor to white.
Repeat with the remainder of thecellulose-copper-ammonia solution.Wash the rayon good with H2O before managing.Record your observations of the rayon.
POLYSTYRENE, An Addition Polymer:
Polystyrene is used to do many types of containers such as videocassette instances, compact disc gem boxes, tableware ( forks, knives and spoons ) , and cafeteria trays. A foamed signifier of polystyrene is used to do java cups, food market shop meat trays, and edifice insularity.
To minimise exhausts in the research lab, this process uses a cinnamene projecting rosin.
Wear safety goggles at all times in the research lab. Styrene is harmful by inspiration. It is an thorn to the eyes and respiratory system.
Work in a good ventilated country. Methyl ethyl ketone is an thorn. Work in a good ventilated country.
Styrene casting rosinProjecting rosin accelerator, methyl ethyl ketoneOne-half of a little petri dishStiring rodOptional: A clean dry coin, such as a penny
Measure 15 milliliter of cinnamene projecting rosin into a paper cup.Add 5 beads of accelerator to the rosin. Stir good.Pour the rosin mixture into a clean half of a petri dish. Let the mixture to sit, undisturbed, for about one hr or until difficult.
If desired, a clean, dry penny can be added to the rosin after it has set for about 5 proceedingss. Toavoid air bubbles, coat the penny with a little sum of the assorted rosin before adding it to the rosin mixture in the petri dish.
NYLON, A Condensation Polymer:
Nylon was the consequence of research directed by Wallace Hume Carothers at du Pont. The research squad was interested in doubling the features of silk.
Nylon gained rapid credence for usage in stockings and in doing parachutes. Carothers, nevertheless, was capable to turns of depression and in 1937, shortly before du Pont placed nylon stockings on the market, Carothers committed self-destruction by imbibing nitrile.
Wear safety goggles at all times in the research lab.The stuffs in this experiment are considered toxic. They are thorns to the eyes and mucose membranes. Wear baseball mitts and work in a good ventilated country.
Hexamethylenediamine ( 1,6-hexanediamine ) , 5 % aqueous solution Sebacoyl chloride ( or adipyl chloride ) , 5 % solution in cyclohexane Sodium hydrated oxide, NaOH, 20 % aqueous solutionBeaker, 50 milliliterForcepssStiring rod.
Pour 10 milliliter of hexamethylenediamine solution into a 50 milliliter beaker.Add 10 beads of 20 % Na hydroxide solution. Stir.Carefully add 10 milliliter of sebacoyl chloride solution by pouring it down the wall of the atilt beaker.
Two beds should be apparent in the beaker and there should be an immediate formation of a polymer movie at the interface between the two liquids.Using forceps, pick up the mass at the centre and easy pull out the nylon, leting a “ rope ” to be formed. Use a stirring rod to wrap the rope and go on to draw it easy from the mixture interface.Wash the nylon good with H2O before managing.Stir any staying solutions left in the beak to organize extra polymer.
Wash the nylon good with H2O.Commercially, nylon is made by blending the constituents in majority. Nylon yarn, rod, and sheet are made by runing and organizing or squeeze outing the polymer.
SODIUM POLYACRYLATE, A Copolymer:
Superabsorbants were originally developed by the United States Department of Agriculture in 1966. This stuff consisted of a grafted copolymer of hydrolyzed starch-polyacrylonitrile ( polyacrylonitrile is normally known as Acrilan, Orion, or Creslan ) . The intended usage was for additives for boring fluid in off-shore secondary oil recovery operations and as agricultural thickenings.
These stuffs were followed by man-made superabsorbants that arepolyacrylic and polyacrylonitrile based. Some of these stuffs are capable of absorbing up to 2000 times their weight of distilled H2O.When a starch-hydrolyzed polyacrylonitrile superabsorbant is assorted with glycerol or ethene ethanediol, the resulting house gel has a rubbery texture and is really strong and resilient. This stuff can absorb approximately 300 to 400 times itsweight in distilled H2O and can “ turn ” many times its original size. This stuff was formed into assorted forms and sold under names such as “ Grow Creatures ” .
The procedure is reversible and, on standing in air, the grow animal will shrivel about to its original size on drying. It can be grown and dried many times.A utile application of “ Super Slurper ” is in the line drives of Pampers and other disposable nappies. Under this application, the polymer gel can absorb up to 90 times its weight in liquid.Super-absorbent stuff, sold under the name “ Water Grabber ” or “ Water Lock ” is available from garden supply shops and can be found in the garden section of some assortment shops.
There are no safety jeopardies with the stuffs used in this experiment.
Sodium polyacrylateSodium chloride, NaCIPaper cup, 5 ozStiring rodDisposable nappyNewspaper
Measure a degree A? teaspoon of superabsorbent stuff and topographic point the stuff in a 5 oz paper or fictile cup.Add 100 milliliter of H2O to the cup.
Record your observations.Add 1/2 teaspoon of salt, Na chloride, to the mixture. Record your observations.
Sodium polyacrylate from a disposable nappy:
To obtain the superabsorbant stuff from a disposable nappy: Obtain an ultra-absorbent nappy. Spread out some newspaper on a table top or the floor.Slowly, take the diaper apart. Observe the different beds. What is the map of each bed?Shake the cotton good to take any superabsorbent stuff.
Throw the waste cotton into the rubbish. Rub the outside line drive of the nappy to take any superabsorbent stuff adhering to the plastic.Transfer the pulverization and cotton on the newspaper to a 5 oz.
plastic or paper cup. Remove any loose cotton, go forthing the pulverization in the cup. Add 50 milliliter of H2O to the pulverization in the cup and splash. Detect the stuff in the cup for about a minute. Record your observations.Testing a disposable nappy: Open a disposable nappy on the bench top.Add H2O, 100 milliliter at a clip, until the nappy does non keep extra H2O.
Record the sum of H2O held by the nappy.
Some Inorganic Polymers:
Some illustrations of-Inorganic Polymers: ( Ref. : H. R. Allcock, Scientific American, 230, 66, March 1974 )Glass: made of rings and ironss of reiterating silicate units. Glass fibres ( fibreglass ) are used in fabrics and in many building stuffs.
Bricks, concrete and ceramics are 3-dimensional polymers.Polyphosphazenes: general expression ( NPCl2 ) N. Formed from responding NH4Cl with PCl5 at 250A°C for several hours. Can be substituted to change belongingss.
It is recommended that a hot home base be used in heating the S in this readying. This will forestall the S from lighting and firing to organize toxic S dioxide, a strong thorn. Keep the beaker of sulfur covered with a ticker glass to minimise sulfur bluess get awaying from the beaker.
Heat ordinary S to a temperature between 140-170A°C.
The S will turn ruddy and become syrupy above 159A°C. At 175A°C, the viscousness of the liquefied S begins to diminish.Pour the hot thaw into H2O in a thin watercourse. When cool, it forms rubberlike fibres of the Polymeric S. The polymer is non stable at room temperature and it will finally indurate, returning to its normal xanthous colour, when the molecules reform into 8-membered rings.
SILLY PUTTY, An Inorganic Polymer:
Silly Putty is a silicone polymer marketed by Binney & A ; Smith Inc. Easton, PA 18042, and with similar merchandises marketed under other names by other companies.
It comes packaged in little elliptic containers and is normally pink in colour. Some signifiers of Silly Putty contain phosphorescent stuff that will let it to glow in the dark.Silly Putty is a non-Newtonian fluid which has dilantant belongingss.
That is, it tends to distend ( or expand ) when sheared ensuing in an increased viscousness under emphasis. For this ground, Silly Putty has some alone belongingss:a ) Under low emphasis, such as easy drawing the Silly Putty apart, the putty flows organizing thin strands.B ) Under high emphasis, such as a crisp pull, the putty interruptions.degree Celsius ) If rolled into a ball and dropped, the putty will resile.vitamin D ) If the ball of putty is placed on a table top and hit with your manus, the ball will barely be deformed. If hitwith a cock, the putty will shatter.
Yet, if you squeeze gently, the ball will flatten.vitamin E ) If you stuff the putty through a tubing, it will swell as it emerges from the unfastened terminal. This is known as dieswell.( This works good with newly prepared putty as the putty tends to indurate with age. )
The Preparation of Silly Putty
dimethyldichlorosilane, SiCl2 ( CH3 ) 2diethyl quintessence, anhydrous, ( C2H5 ) 2ONa H carbonate, NaHCO3, saturated aqueous solutionboracic oxide, B2O3 sometimes called boracic acid, fused )Na sulphate, Na2SO4, anhydroussafety shieldflask, 250-mL, and 125-mLseparatory funneltrial tubing, Pyrex, 25 ten 250 millimeterstirring rod
Wear safety goggles at all times in the research lab.Dimethyldichlorosilane reacts violently with H2O to bring forth heat and toxic and caustic exhausts ( HCl ) .
Avoid tegument contact and utilize it merely in a fume goon.Ether is highly flammable, avoid the usage of fires in the research lab during this process.When rinsing the ether solution with Na H carbonate, C dioxide is released constructing up force per unit area in the separatory funnel.
Vent the funnel frequently.
This process must be carried out in a fume goon or in an country with first-class airing and behind a safety shield.To a 250-mL flask add 20 milliliter of dimethyldichlorosilane and 40 milliliter of anhydrous quintessence. Hydrolyze the solution by adding 40 milliliter distilled H2O DROPWISE, leting the reaction to discontinue before adding extra H2O. ( If H2O is added excessively quickly, the reaction will continue smartly and may splatter from the flask. Avoid inhaling any bluess from the flask. )After the H2O add-on is complete, reassign the reaction mixture to a separatory funnel and run out away and fling the H2O bed. Wash the staying ether solution with 10 mL parts of concentrated Na H carbonate, venting frequently, until it is no longer acid ( and no more CO2 signifiers ) , so wash with 10 milliliter of distilled H2O.
Drain the quintessence bed into a 125-mL flask incorporating 2 gms Na2SO4 and let to dry for 15-20 proceedingss.Filter the solution into a 100-mL beaker and transportation to a H2O bath or steam bath to vaporize the quintessence.Determine the mass of the residuary silicone oil. Add about 5 % of the silicone oil ‘s mass of boracic oxide, and splash for a few proceedingss. Transfer the mixture to a Pyrex trial tubing and heat in an oil bath at 200`C for three hours. Let the cockamamie putty to chill.Note: Initially, the cockamamie putty will be a clear, colorless to somewhat xanthous stuff.
It will bring around within one hebdomad to a white solid with belongingss closer to the commercially available Silly Putty. As it is used, it will pick up foreign affair and go grey in colour easy bettering its belongingss.
Application and future prospective:
Macromolecular scientific discipline has had a major impact on the manner we live.
It is hard to happen an facet of our lives that is non affected by polymers. Merely 50 old ages ago, stuffs we now take for granted were non-existent. With farther progresss in the apprehension of polymers, and with new applications being researched, there is no ground to believe that the revolution will halt any clip shortly.Wood cellulose, a versatile and renewable natural resource, has potency for usage as a support for man-made organic polymers. During the past 80 old ages a figure of stuffs utilizing the reenforcing belongingss of wood cellulose have found major markets. Forms of wood cellulose proposed as supports include: wood fibres, cellulose fibres, microfibillar, and microcrystalline cellulose. Recent attending has been given to them as fillers/reinforcements in thermoplastics and elastomers. Most cellulosic complexs derive their being from their relatively low stuffs cost and the filling instead than reenforcing belongingss of cellulose.
However, cellulose ironss have a possible stiffness much higher than glass and in the same scope as superstiff aramid fibres.In this paper I examined different utilizations and readying for different polymers. And at last Icame to the decision that polymers are utile to human being in every facet of life. Almost all the substances we use for our convenience are made of different types of polymers.