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Acrylic Fiber
• The Fiber that contain the concentration of ACRYLONITRILE up to 85 %.
MOD-Acrylic
• The Fiber That Contain the concentration of ACRYLONITRILE between 35-85%.
Basic Structure
• Structure of AcrylonitrileCH2 CH
CN
Single Unit of Acrylonitrile
Manufacturing of Acrylonitrile
• Using HCN:
– Ethylene & HCN– Acetylene & HCN– Acetaldehyde & HCN
Ethylene & HCN
• Steps Involve:
– It is a Two Stage Process:
• Ethylene Oxide + HCN Cyanohydrene
• Ethylene Cyanohydrin Acrylonitrile + H2OCH2 = CH -- CN + H2O
At Last Fractional Distillation is used to separate Acrylonitrile
• Catalyst Involve:– Magnesium Carbonate
• Temperature:– Max 55 60
Ethylene & HCN
Acetylene & HCN
• Steps Involve:
– One Step Process:Acetylene + HCN Acrylonitrile
C2 H2 + HCN CH2 == CH-CN
• Catalyst Involve:– CuCl2 & NH4Cl
Because CuCl2 is not much soluble that’s why NH4Cl is used.
• Temperature:– Max 80 90C
Fractional Distillation is also used here.
Acetylene & HCN
Acetaldehyde & HCN
• Steps Involve:
– Two Step Process:
• Acetaldehyde+ HCN LactonitrileCH3 CHO + HCN CH3 CHO HCN
• Lactonitrile AcrylonitrileCH3 CHO HCN CH2 == CHCN +H2O
Distillation used here also
• Catalyst Involve:– Phosphoric Acid
• Temperature:– Max 600 700C
Acetaldehyde & HCN
Manufacturing of Acrylonitrile
• Using Propylene:
– The Sohio Process– The DuPont Process– The Distillers Process
The Sohio Process
• Steps Involve:
• One Step Process:• Ammonoxidation of Propylene is preformed here
CH2=CHCH3 + NH3 + 1.5O2 CH2=CHCN + 3H2O
• Catalyst Involve:– Bismuth Phosphomolybdate
• Temperature:– Max 425 510 C
• Pressure:– 2 3 atm
The Sohio Process
The DuPont Process
• Steps Involve:
– One Step Process:
• Propylene react with NO here:4CH2=CHCH3 + 6NO 4CH2=CH – CN + N2 + 6H2O
• Catalyst:– Ag except silica
• Temperature:– Max 460 500 C
The DuPont Process
The Distillers Process
• Steps Involve:
– Two Stage Process:• Oxidation of Propylene is preformed here to give
AcroleinCH2–CH=CH2 O=CHCH=CH2
• Acrolein Acrylonitrile:O=CHCH=CH2 + NH3 + CH=CH2
• Catalyst:– Molybdenum Oxide
• Temperature:– Max 380 C
The Distillers Process
Polymerization
• The process of joining together monomers to produce a molecular chain called polymerization.
• Bulk PolymerizationPolymerization without any catalyst is called bulk polymerization you may call it step growth polymerization.
• Solution PolymerizationA polymerization process in which monomers and catalyst are dissolved in non reactive solvent.
Polymerization
Properties of Acrylonitrile
• SolubilityAcrylonitrile is not easily soluble in water and other solvents temperature and strong acids or bases are used for this purpse.
Properties of MOD-Acrylic
• Resistance to HeatSensitive to heat, melt above 220C, require great care in ironing.
• Moisture AbsorptionQuite insensitive to water at room temperaturemaximum absorption of one of mod acrylic type is 3.0-3.5% but absorption will never effect mechanical properties.
Properties of MOD-Acrylic
• Mechanical PropertiesMax Tenacity of any type is 2.0-3.5g/denElastic recovery %---100% at double and 98% at 5 times.
• Resistance to ChemicalsHigh resistance to chemicals because of high crystallinity and less amorphous part. Crystalline part is from 75-85% and the rest is amorphous.
Properties of MOD-Acrylic
• Resistance to:
» Insects» Fungus» Bacteria
• High resistance to all of above because of its crystallinity, elasticity and mechanical strength
Manufacturing Processes
• Wet Spinning• Dry Spinning • Extruded in Melted State
Manufacturing Process
• Spinning Solution:
– Solvent
– Dissolving Polyacrylonitrile• Lumps: Irregular shape is called lump
– Main Concept• Solute & Solvent
Dimethylformamide, Dimethylacetamide
• Wet Spinning:
– Filtration of Solution• Holes for filtration are---- min 1000, max 30000
– Spinning Bath• To remove impurities this process is used
Rate at which it is preformed 5 & 20 meter/min
Manufacturing Processes
• Spinning Bath– Coagulating Bath: To remove impurities
– Washing: Washing is washing nothing special
– Stretching: To enhance mechanical properties
– Finishing: To make resulted yarn useable
– Crimping: The process of creation of Crimps (Ziq-Zag)
Manufacturing Processes
Wet Spinning of Acrylics
• Washing: Defined in wet spinning above
• Stretching: Defined in wet spinning above
• Tow: To dry the product
• Crimp: Defined in wet spinning above
Dry Spinning
Dry Spinning
Properties & Uses
• Apparel:
– Socks– Sweaters– Fleece Wear– Sports-Wear– Children's-Wear
• Home Furnishing:
– Blankets– Awnings– Area Rugs– Upholstery– Out-Door Furniture
Properties & Uses
Properties & Uses
• Socks:
Properties & Uses
• Sweaters:
Properties & Uses
• Fleece Wear:
Properties & Uses
• Blankets:
Properties & Uses
• Awnings:
Properties & Uses
• Rugs:
Properties & Uses
• Upholstery:
• Out-Door Furniture:
Properties & Uses
Danger To Wool
• Acrylics are Dangerous to
Wool