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