Synthetic Strategies in the Preparation of Polymer/Inorganic Hybrid ...
Synthetic Polymer Industries
Transcript of Synthetic Polymer Industries
-
7/29/2019 Synthetic Polymer Industries
1/52
Synthetic Polymer
Industries
Notes for student use
-
7/29/2019 Synthetic Polymer Industries
2/52
Plastic Industries
-
7/29/2019 Synthetic Polymer Industries
3/52
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 into
finished 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.
-
7/29/2019 Synthetic Polymer Industries
4/52
-
7/29/2019 Synthetic Polymer Industries
5/52
-
7/29/2019 Synthetic Polymer Industries
6/52
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.
-
7/29/2019 Synthetic Polymer Industries
7/52
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.
-
7/29/2019 Synthetic Polymer Industries
8/52
Applications and UsesCommon Resin Types and Applications
Resin Type Applications
Polyesters Construction, auto repair putty, laminates, skis,
fishing rods, boats and aircraft component,
coatings, decorative fixtures, bottles
Polyurethanes Insulation, foam inner liners for clothing, rocket fuel
binders, elastomers, adhesives
Polyethers Coatings, pump gears, water-meter parts, bearing
surfaces, valves
-
7/29/2019 Synthetic Polymer Industries
9/52
Applications and UsesCommon Resin Types and Applications
Resin Type Applications
Epoxies Laminates, adhesives, flooring, linings, propellers,
surface coatings
Polyethylene Packaging films and sheets, containers, wire cable
insulation, pipe, linings, coatings, molds, toys,
housewares
Polypropylene Housewares, medical equipment (can be sterilized),
appliances, toys, electronic components, tubings and
pipes, fibers and filaments, coatings
-
7/29/2019 Synthetic Polymer Industries
10/52
Applications and UsesCommon Resin Types and Applications
Resin Type Applications
Polyvinyl chloride Pipe and tubing, pipe fittings, adhesives, raincoats
and baby pants, building panels
Acrylics Decorative and structural panels, massive glazing
domes, automotive lens systems, illuminated
translucent floor tiles, windows, and canopies
Polystyrene Insulation, pipe, foams, cooling towers, thin-walled
containers, appliances, rubbers, automotive
instruments and panels
-
7/29/2019 Synthetic Polymer Industries
11/52
Plastics in Everyday Life
-
7/29/2019 Synthetic Polymer Industries
12/52
Standard Symbols
-
7/29/2019 Synthetic Polymer Industries
13/52
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.
-
7/29/2019 Synthetic Polymer Industries
14/52
Manufacturing Processes
is carried out in the liquid or vapor state.
The monomers and activator are mixed in a reactor
and heated or cooled as needed.
Bulk
Polymerization
is used when the exothermic heat is too great to becontrolled in bulk polymerization.
The monomer and initiator are dissolved in a
nonreactive solvent which serves to slow the
reaction and thus moderate the heat given off.
SolutionPolymerization
-
7/29/2019 Synthetic Polymer Industries
15/52
Manufacturing Processes
is the process where the monomer is suspended in
water by agitation.
stabilizers (i.e. talc, fullers earth, and bentonite) areadded to stabilize the suspension and prevent
polymer globules from adhering to each other.
Suspension
Polymerization
is similar to suspension polymerization but the monomer
is broken up into droplets that form aggregates called
micelles.
The monomer is on the interior of the micelles, and the
initiator is in the water. Soap or another emulsifying agent
is used to stabilize the micelles.
EmulsionPolymerization
-
7/29/2019 Synthetic Polymer Industries
16/52
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.
-
7/29/2019 Synthetic Polymer Industries
17/52
Polyethylene
-
7/29/2019 Synthetic Polymer Industries
18/52
The Process Flow of LDPE Production
-
7/29/2019 Synthetic Polymer Industries
19/52
Individual Process Descriptions
1. Demethanization and Deethanization The
feed for the process is a mixture of methane,
ethane, and ethylene. Since ethylene is the
monomer to be used ethylene has to be
separated from methane and ethane. High
purity ethylene is used (99.8%).
-
7/29/2019 Synthetic Polymer Industries
20/52
Individual Process Descriptions
2. Compression of Ethylene and Catalyst -
Ethylene and the catalyst (free-radical yielding
such as oxygen or peroxide) are compressed
to operating pressure (150 MPa).
-
7/29/2019 Synthetic Polymer Industries
21/52
Individual Process Descriptions
3. Solution Polymerization In a tubular reactor
maintained at 190C, solution polymerization
occurs to convert ethylene to polyethylene.
About 30% conversion is achieved per pass.
-
7/29/2019 Synthetic Polymer Industries
22/52
Individual Process Descriptions
4. Pressure Separation
At this stage, the
unconverted ethylene is
removed and recycled.
-
7/29/2019 Synthetic Polymer Industries
23/52
Individual Process Descriptions
5. Extrusion and Pelletizing The polyethylene
is extruded and pelletized.
-
7/29/2019 Synthetic Polymer Industries
24/52
Individual Process Descriptions
6. Quench Cooling This hardens the
polyethylene pellets by addition of cold water.
-
7/29/2019 Synthetic Polymer Industries
25/52
Individual Process Descriptions
7. Water Separation and Drying These involve
the removal of water from the pellets to
obtain the final product.
-
7/29/2019 Synthetic Polymer Industries
26/52
Man-Made Fiber and
Film Industries
-
7/29/2019 Synthetic Polymer Industries
27/52
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.
-
7/29/2019 Synthetic Polymer Industries
28/52
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.
-
7/29/2019 Synthetic Polymer Industries
29/52
Synthetic Fibers and their
Applications
PolyamidesThey 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.
-
7/29/2019 Synthetic Polymer Industries
30/52
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 aging
makes Vinyon useful in heat-sealing fabrics andclothing.
-
7/29/2019 Synthetic Polymer Industries
31/52
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 Fibersare used for electrical insulation inmotors and generators, structural reinforcement ofplastics, fire-proof wall coverings and tire cords.
-
7/29/2019 Synthetic Polymer Industries
32/52
Multicomponent fibers
Multicomponent fibers have been prepared
which possess superior properties to either
component if spun alone. They correspond to
better dyeability, permanent crimp, or silklikefeel, etc.
-
7/29/2019 Synthetic Polymer Industries
33/52
Finishing and Dyeing of Textiles
Dyeing, bleaching, printing, and special finishing (such as for crease
recovery, dimensional stability, resistance to microbial attack and
ultraviolet light) involve unit operations such as filtering, heating, cooling,
evaporation and mixing.
-
7/29/2019 Synthetic Polymer Industries
34/52
Films
are made fromdifferentpolymers such aspolyesters,
polyvinyl chloride,etc.
-
7/29/2019 Synthetic Polymer Industries
35/52
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.
-
7/29/2019 Synthetic Polymer Industries
36/52
Nylon 6.6
Nylon 6.6 was the first all-synthetic fiber made
commercially and opened up the entire field.
It is the product resulting from the
polymerization of adipic acid and
hexamethylene diamine.
-
7/29/2019 Synthetic Polymer Industries
37/52
PFD for Nylon Production
-
7/29/2019 Synthetic Polymer Industries
38/52
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.
-
7/29/2019 Synthetic Polymer Industries
39/52
Individual Process Description
1. Nylon Salt Formation - The reaction between equimolar proportions
of the two raw materials produces nylon salt solution. Acetic acid is
added to the (hexa) to to stabilize chain length.
-
7/29/2019 Synthetic Polymer Industries
40/52
Individual Process Description
2. Evaporation The water produced from the reaction is evaporated in an
evaporator and a jacketed autoclave.
In the jacketed autoclave, pure nitrogen at 175-345 kPa forces the
material downward. TiO2 dispersion is also added.
-
7/29/2019 Synthetic Polymer Industries
41/52
Individual Process Description
3. 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 cat
drum.
Water sprays on the inside cools and harden the underside of the ribbon, theouter is cooled by air and water.
-
7/29/2019 Synthetic Polymer Industries
42/52
Individual Process
Description
4. Blender and Hopper
The ribbons are cut into
small chips or flakes, blended and emptied to
hoppers.
-
7/29/2019 Synthetic Polymer Industries
43/52
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 (263C).
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 spinneret
plate.
The filaments are solidified by air and passed in a bundle through steam-humidifying chamber.
-
7/29/2019 Synthetic Polymer Industries
44/52
Melt Spinning
-
7/29/2019 Synthetic Polymer Industries
45/52
Individual Process Description
6. Cold Drawing
After lubrication on
a finish roll, the yarn is stretched
or drawn to the desired degree.
7. Bobbin The nylon yarn passes
through a bobbin system and is
shipped to various manufacturers
for processing.
-
7/29/2019 Synthetic Polymer Industries
46/52
-
7/29/2019 Synthetic Polymer Industries
47/52
-
7/29/2019 Synthetic Polymer Industries
48/52
-
7/29/2019 Synthetic Polymer Industries
49/52
-
7/29/2019 Synthetic Polymer Industries
50/52
-
7/29/2019 Synthetic Polymer Industries
51/52
-
7/29/2019 Synthetic Polymer Industries
52/52
THANQ -
SALAMAT NG MARAMI. =)
Reference
Austin, G.T. Shreves Chemical Process
Industries (5th Ed). New York: McGraw-Hill, Inc., 1984.