Overview• A plastic is a material that contains a polymerizedorganic substance of large molecular weight as anessential ingredient, is solid in its finished state, and atsome stage in its manufacture or its processing intofinished articles can be shaped by flow.• The plastic industries have developed and grown then,since their discovery. Plastics can be used in variousapplications because of their toughness, waterresistance, excellent resistance to corrosion, ease offabrication, and remarkable color range.
History• The development of commercial phenolic resin in 1909 byBaekland was the start of the synthetic plastic industry. Hisdiscovery stimulated the search for other plastics.• The first plastic of industrial significance was cellulosenitrate (Celluloid) and was discovered about the middle ofthe nineteenth century. It was first used in 1869 by Hyattwho was searching for an ivory substitute.
Classification• Thermosetting plastics are processed by heatcuring to produce an infusible or insolubleproduct.• Thermoplastics are processed by heating tosoften them and cooling to harden them.• On the basis of derivation, they may also begrouped as natural resins, cellulose derivatives,protein products, and synthetic resins.
Applications and UsesCommon Resin Types and ApplicationsResin Type ApplicationsPolyesters Construction, auto repair putty, laminates, skis,fishing rods, boats and aircraft component,coatings, decorative fixtures, bottlesPolyurethanes Insulation, foam inner liners for clothing, rocket fuelbinders, elastomers, adhesivesPolyethers Coatings, pump gears, water-meter parts, bearingsurfaces, valves
Applications and UsesCommon Resin Types and ApplicationsResin Type ApplicationsEpoxies Laminates, adhesives, flooring, linings, propellers,surface coatingsPolyethylene Packaging films and sheets, containers, wire cableinsulation, pipe, linings, coatings, molds, toys,housewaresPolypropylene Housewares, medical equipment (can be sterilized),appliances, toys, electronic components, tubings andpipes, fibers and filaments, coatings
Applications and UsesCommon Resin Types and ApplicationsResin Type ApplicationsPolyvinyl chloride Pipe and tubing, pipe fittings, adhesives, raincoatsand baby pants, building panelsAcrylics Decorative and structural panels, massive glazingdomes, automotive lens systems, illuminatedtranslucent floor tiles, windows, and canopiesPolystyrene Insulation, pipe, foams, cooling towers, thin-walledcontainers, appliances, rubbers, automotiveinstruments and panels
Raw Materials• Monomers: vinyl chloride, ethylene, propyleneand similar simple hydrocarbons• Chemical intermediates : phenol, formaldehyde,hexamethylenetetramine, phthalic anhydride,methyl acrylate and methacrylate• Other raw materials: plasticizers, fillers, andreinforcements are also added to alter theproperties of the plastic products.
Manufacturing Processes• is carried out in the liquid or vapor state.• The monomers and activator are mixed in a reactorand heated or cooled as needed.BulkPolymerization• is used when the exothermic heat is too great to becontrolled in bulk polymerization.• The monomer and initiator are dissolved in anonreactive solvent which serves to slow thereaction and thus moderate the heat given off.SolutionPolymerization
Manufacturing Processes• is the process where the monomer is suspended inwater by agitation.• stabilizers (i.e. talc, fuller’s earth, and bentonite) areadded to stabilize the suspension and preventpolymer globules from adhering to each other.SuspensionPolymerization•is similar to suspension polymerization but the monomeris broken up into droplets that form aggregates calledmicelles.•The monomer is on the interior of the micelles, and theinitiator is in the water. Soap or another emulsifying agentis used to stabilize the micelles.EmulsionPolymerization
Polyethylene• It is the first and the largest in production ofpolyolefin plastic.• High-density polyethylene (HDPE), produced bylow-pressure methods, is used mainly for blow-molded containers and injection-molded articlesand pipe.• Low-density polyethylene (LDPE), produced byhigh-pressure methods, is used mainly for plasticfilms.
Individual Process Descriptions1. Demethanization and Deethanization – Thefeed for the process is a mixture of methane,ethane, and ethylene. Since ethylene is themonomer to be used ethylene has to beseparated from methane and ethane. Highpurity ethylene is used (99.8%).
Individual Process Descriptions2. Compression of Ethylene and Catalyst -Ethylene and the catalyst (free-radical yieldingsuch as oxygen or peroxide) are compressedto operating pressure (150 MPa).
Individual Process Descriptions3. Solution Polymerization – In a tubular reactormaintained at 190°C, solution polymerizationoccurs to convert ethylene to polyethylene.About 30% conversion is achieved per pass.
Individual Process Descriptions4. Pressure Separation– At this stage, theunconverted ethylene isremoved and recycled.
Individual Process Descriptions5. Extrusion and Pelletizing – The polyethyleneis extruded and pelletized.
Individual Process Descriptions6. Quench Cooling – This hardens thepolyethylene pellets by addition of cold water.
Individual Process Descriptions7. Water Separation and Drying – These involvethe removal of water from the pellets toobtain the final product.
ClassificationAccording to Spinning Procedures• Melt spinning involves pumping molten polymer throughcapillaries or spinnerets and the polymer streams thatemerge are solidified by quenching in cool air.• In dry spinning, the polymer is dissolved in a suitableorganic solvent. The solution is forced through spinneretsand dry filaments are formed upon evaporation of thesolvent.• Wet spinning involves spinning of a solution of polymerand coagulation of the fiber in a chemical bath.
Overview• Fibers were originally of natural origin and wereproduced from wool, silk, cotton, flax, and similarmaterials.• The first man-made fibers were made by Swan in1883 when he squirted a solution of cellulosenitrate in acetic acid through holes.• Fibers have three important general properties:length, crimp and denier.
Synthetic Fibers and theirApplications• Polyamides –They are used in home furnishings,especially carpets.• Acrylics and Modacrylics – polyacrylonitrile is themajor component of several industrial textilefibers.• Spandex – It is used in foundation garments,hose, swimwear and other elastic products.
Vinyls and Vinylidines• Saran is the copolymer of vinyl chloride and andvinylidene chloride. It is resistant to mildew, bacterialand insect attack. Automobile seat covers and homeupholstery are its prime applications.• Vinyon is the trade name of copolymers of 90% vinylchloride and 10% vinyl acetate.Resistance to acids and alkalies, sunlight, and agingmakes Vinyon useful in heat-sealing fabrics andclothing.
Other Synthetic Fibers• Polyolefins – They excel in special cases, such as ropes,laundy nets, carpets, blankets and backing for tuffedcarpets, but are difficult to dye and their melting pointis low.• Fluorocarbons – It is widely used in pump packings andshaft bearings.• Glass Fibers – are used for electrical insulation inmotors and generators, structural reinforcement ofplastics, fire-proof wall coverings and tire cords.
Multicomponent fibers• Multicomponent fibers have been preparedwhich possess superior properties to eithercomponent if spun alone.• They correspond to• better dyeability,• permanent crimp, or• silk like feel, etc.
Finishing and Dyeing of Textiles• Dyeing, bleaching, printing, and special finishing (such as for creaserecovery, dimensional stability, resistance to microbial attack andultraviolet light) involve unit operations such as filtering, heating, cooling,evaporation and mixing.
Films• are made fromdifferentpolymers such aspolyesters,polyvinyl chloride,etc.
3 Common Types of Film Processing• Slit-die process – produces flat sheets by extruding themolten polymer through a slit-die into a quenchingwater bath or onto a chilled roller.• Blow-extrusion Process – produces tubular film byusing air pressure to force the molten polymer arounda mandrel.• Calendering – preparation of film is produced byfeeding a plastic mix of polymer, stabilizer, andplasticizers between two heated roll where it issqueezed into a film.
Nylon 6.6• Nylon 6.6 was the first all-synthetic fiber madecommercially and opened up the entire field.• It is the product resulting from thepolymerization of adipic acid andhexamethylene diamine.
Raw Materials• The raw materials for fiber production are justthe same as in plastics production and willdepend on the type of material the fiber is madeup of.• For the production of nylon yarn, however, theraw materials cited are adipic acid andhexamethylene diamine (“hexa”).• Utilities such as steam and water will also beused.
Individual Process Description1. Nylon Salt Formation - The reaction between equimolar proportionsof the two raw materials produces nylon salt solution. Acetic acid isadded to the (“hexa”) to to stabilize chain length.
Individual Process Description2. Evaporation – The water produced from the reaction is evaporated in anevaporator and a jacketed autoclave.• In the jacketed autoclave, pure nitrogen at 175-345 kPa forces thematerial downward. TiO2 dispersion is also added.
Individual Process Description3. Casting Wheel – Each 900-kg batch is extruded as rapidly as possible.• A ribbon of polymer about 30 cm wide and 6 mm thick flows on the 1.8-m catdrum.• Water sprays on the inside cools and harden the underside of the ribbon, theouter is cooled by air and water.
Individual ProcessDescription4. Blender and Hopper – The ribbons are cut intosmall chips or flakes, blended and emptied tohoppers.
Individual Process Description• Melt Spinning – A typical spinning unit is composed of a metal vesselsurrounded by a Dowtherm vapor heated jacket which keeps thetemperature of the vessel above melting temperature (263°C).• As the nylon flake enters the vessel, it strikes a grid, where it melts andflows through to the melt chamber below.• The molten polymer passes through the portholes in this chamber to gearspinning pump.• They deliver it to a sand filter, which is followed by screens and a spinneretplate.• The filaments are solidified by air and passed in a bundle through steam-humidifying chamber.
Individual Process Description6. Cold Drawing – After lubrication ona finish roll, the yarn is stretchedor drawn to the desired degree.7. Bobbin – The nylon yarn passesthrough a bobbin system and isshipped to various manufacturersfor processing.
NEWS: Drydens Outlines of Chemical Technology-For the 21stCentury,... OverviewAn unrivaled library of information for the chemical industry. TheFourth Edition will be completely revised and will include many newsubjects reflecting the growth and changes in chemical technologythrough the 1990s. It will consist of 27 volumes which will be issuedat the rate of approximately four volumes per year. In addition toupdating traditional subjects, the new edition will include expandedcoverage of biotechnology, materials science, computer technology,energy sources and conversion techniques, and environmentalissues such as pollution control, toxicology, and recycling technology.The Fourth Edition will bring together over 1000 articles byrecognized experts in their areas of chemical technology, and willdeal with industrial products, natural materials, and processes in suchfields as: agricultural chemicals, chemical engineering, coatings andinks, composite materials, cosmetics and pharmaceuticals, dyes,pigments and brighteners, ecology and industrial hygiene, energyconservation and technology, fats and waxes, fermentation andenzyme technology, fibers, textiles
ReferenceChemicals From Petroleum by A L WaddamsChemical Publishing Book - HardbackPub Date: Jul 28, 1969, 260 pagesBackground to petroleum chemicals - Introduction -Characteristics of Petroleum Chemical Manufacture -Raw Materials - Petroleum chemical products andtheir Applications
ReferenceAn introduction to industrial organicChemistry by Peter Wiseman, Wiley Interscience, 1972Publisher: Elsevier Science Ltd; 2nd edition (July 1979)
References: 1) Austin, G.T. Shreve’s Chemical ProcessIndustries (5th Ed). New York: McGraw-Hill, Inc., 1984.2) Industrial organic chemistry / Klaus Weissermel ;Hans- Jiirgen Arpe. Transl. by Charlet R. Lindley. ~ 3.,completely rev. ed. ~ Weinheim : VCH, 19973) Drydens Outlines of Chemical Technology-For the21st Century, 3/e, M Gopala Rao, Affiliated East WestPress Pvt. Ltd. New Delhi