MMET 206 Test 2
Plastic Recycling
1. PETE or PET - Polyethylene Terephthalate 2. HDPE - High Density Polyethylene 3. V or PVC - Polyvinyl Chloride 4. LDPE - Low Density Polyethylene 5. PP - Polypropylene 6. PS - Polystyrene
Unsaturated HCs (Double C-C bond) 17%
Aromatics ~17% Unsaturated Rings
(TP) Cast Film Extrusion
BOPET, BOPP, BOPA films are made by this method.
Before mixing with a hardener, the epoxy resin that you used in your composite lab is a _____, and the plastic pellets you used in your injection molding lab is a _______.
Matrix Material/Thermoset, Thermoplastic
Metal Matrix Composites (MMC)
Matrix materials: - Aluminum, magnesium, titanium, cobalt, or cobalt-nickel alloy Reinforcing materials: - Continuous fibers - Discontinuous fibers Example: Modern composite cutting tool material - better strength, wear, & heat resistance - WC inserts (WC particles in cobalt*** matrix) MMC Example: WC + Co*** (10 wt %)
Ceramic Matrix Composites (CMC)
Matrix materials: - Carbon, Silicon carbide (SiC) • Reinforcing materials: - Carbon or silicon carbide fibers
Properties required for a reinforcing fiber:
Very high strength • Very high stiffness • Very low density Carbon Fibers 10 times that of metals
PEEK
high strength and stiffness
Polyoxymethylene (POM, Acetal, Delrin)
strength, toughness and low-friction Plastic molded zipper
3. Prepreg - Preimpregnated Fiber Sheet
• Prepreg - Made by impregnating with resin a sheet-like material - Unidirectional tapes, fabrics, or mats - For manual lay up of laminates - Optimal fiber/matrix ratio
Resins (Polymer Matrix) for Composites
• Thermosets - Epoxy*** (most common for carbon fibers) (stiffest and toughest) - Polyester*** (most common for glass fibers) - Vinyl ester (mainly a substitute for polyester) Thermoplastic - PEEK (Polyetheretherketone): still having fiber wetting problem and used only for special applications
Polyisoprene (IR) - the Synthetic NR
- synthetic natural rubber, excellent resistance to compression set*** and heat buildup***
Linear
- the repeating units are joined together end to end in single chain. (structure of a thermoplastic)
Manufacturing Processes Typical for Thermoplastics (TP)
1) Injection Molding*** 2) Extrusions*** (profile, blown film, cast film, sheet) 3) Blow Molding***
Polyester (PET) can be a thermoplastic or thermoset and are used for:
1) Synthetic fibers 2) Soft drink, food, water, and other liquid containers/bottles 3) Engineering plastic, PET films, thermosetting resins for glass-fiber reinforced composites
How are polymers made?
Natural Resource: crude oil or natural gas - Both crude oil & natural gas are mixtures of various hydrocarbons (HCs)
Latex gloves have been used extensively for various purposes. What are latex gloves made from?
Natural Rubber
Which of the following rubbers is the most commonly used by the seal industry for its excellent resistance to petroleum products such as oil, grease, gasoline, etc.?
Nitrile Rubbers (NBR)
Permeability of Plastics
No plastic can completely block O2 or H2O! Need to employ layers of different polymers for blocking different substances
Yachts or Boats
The main material involved in the marine industry is Glass Fiber Reinforced Plastic (GFRP)
olymethylmethacrylate (PMMA) aka Acrylics, Plexiglas, and Lucite
best light transmittance aircraft windows
Cracking of HCs into Monomers
breaking of C-C and/or C-H bonds using the combinations of heat, catalysts, and pressure.
Most composites are combinations of two materials: _____ material + ______ material
reinforcing***, matrix***
(TP) Rotation Molding
Heating while rotating around two mutually perpendicular axes
Most important chemical feedstocks
Ethylene and Propylene 50- 60% of all organic chemicals.
(TP) Vacuum Thermoforming
Like in Lab with a mold
(TP) Blow Molding
(1) A piece of hot, soft plastic is fixed to the end of an air tube and placed between the two parts of the mold. (2) The two sides of the mold are pushed together and this makes an airtight seal at the top and bottom. (3) Air is blown through the air tube. The hot, soft plastic is forced out against the side of the cavity in the mold. (4) The parts of the mold are separated and the new plastic bottle is removed.
Versions of Blow Molding
(1) Extrusion Blow Molding • Uniaxial molecular orientation (parison) (2) Injection Blow Molding • Preform is produced from injection molding. • Uniaxial molecular orientation (3) Stretch Blow Molding • Biaxial molecular orientation (preform)
(TS) Compression molding
(1) With the dies apart, the prepared polymer 'dough' is placed into the cavity 2) With the die closed, the article is formed and the small amount of flashing on each side will be removed later.
Chloroprene/Neoprene Rubber (CR)
- 1st commercialized synthetic rubber - Oil resistant, good all-purpose rubber
Butyl Rubber (IIR)
- A copolymer of isobutylene and isoprene - The only air impermeable rubber - Used as inner liners for sporting balls, tires of all kinds, and vacuum applications.
Three types of composites:
- CMC (ceramic matrix composites) - MMC (metal matrix composites) - PMC (polymer matrix composites) (most common) (Fibrous PMC)
Manufacturing Processes Typical for Thermosets (TS) (often composites)
- Compression Molding - Reaction Injection Molding - Foaming - Resin Transfer Molding (composite) - Pultrusion (composite)
EPDM Rubber (EPDM)
- Ethylene (45-75%) Propylene (balance) Diene (2.5-12%) Monomer Rubber - Outstanding heat (150C), weather, water and steam resistance; excellent electrical insulating properties. - Car weather seals (door, window, trunk) and hoses; pond liner; playground and pool deck surfacing; and roofing for rainwater harvesting (does not pollute the run-off rainwater).
Important Monomers
- Ethylene (C2H4) for Polyethylene (PE); EPDM rubber - Propylene (C3H6) for PP; EPDM rubber - Vinyl Chloride (C2H3Cl) for PVC - Butadiene (C4H6) for ABS, HIPS; BR, SBR, and EPDM rubbers - Styrene (C8H8) for PS, HIPS, ABS; SBR rubber - Ethylene Terephthalate (C10H8O4) for PET
Butadiene Rubber (BR)
- Excellent abrasion and crack resistance
Synthetic Polymers
- Fibers (e.g., aram (Nomex, Kevlar, Nylon), polyester) - Plastics (e.g., acrylics (plexiglass), PET (drink bottle)) - Elastomers or Rubbers (e.g., styrene butadiene (SBR tires))
Important plastics for their excellent barrier properties:
- HDPE*** and PP*** are excellent H2O barriers, - EVOH*** is the most commonly used O2 barrier.
Silicone Rubber (SI)
- Inorganic polymer - Exceptional heat resistance (316C/600F)
Styrene Butadiene Rubber (SBR)
- Main component for auto tires - SBR+NR account for ~90% world rubber consumption - Excellent abrasion, crack, and aging resistance - Low resilience, low tear strength, poor tack (gripping)
1. Individual Fiber & Matrix:
- Matrix (Liquid Resin) • Thermosetting Polymers (Monomer + Hardener) - Fibers: • Milled Fiber • Chopped Fiber • Continuous Fiber - Roving - Fabric & Mat
Highly Amorphous Polymers
- PMMA - Atactic Polystylene (PS) - Polycarbonate (PC) - Polyisoprene (IR) - Polybutadiene (BR)
3 groups of Crude Oil
- Paraffins (~25%), - Naphthenes (~50%), - Aromatics (~17%), and other non-HCs. - Carbon ~ 83-87% - Hydrogen ~ 11-15%
Highly Crystalline Polymers
- Polypropylene (PP) - Nylon (PA) - Kevlar and Nomex - Syndiotactic Polystylene (PS)
Characteristics of Thermosets
- Stiffer & more brittle than thermoplastics - Better creep resistance, long-term thermal and dimensional stabilities with temperature - Used as resins for making composites
Nitrile Rubber (NBR,Buna-N)
- a copolymer of butadiene and acrylonitrile - Excellent resistance to petroleum - Most widely used rubber in the seal industry***
Thermoplastic Polymers Six Commodity Plastics
1. Polyethylene Terephthalate (PET) 2. High Density Polyethylene (HDPE) 3. Polyvinyl Chloride (PVC) 1-3 are Polyolefins (53%)*** 4. Low Density Polyethylene (LDPE) - including LLDPE 5. Polypropylene (PP) 6. Polystyrene (PS)
(TP) Injection Molding
1. The plastic is placed in a hopper so that it falls into the machine as the screw is turned by the gear. 2. The screw is pushed into the machine and this forces the soft plastic through a small hole into the cavity of the die. The die is cooled to harden the plastic. 3. The die is separated and the plastic item is released. The process is then repeated to make another item.
The specific strength of a carbon fiber is about _____ times that of metals (steel and aluminum).
10
Carbon black makes up about _____ of a tire by weight.
30%
rosslinking of UHMWPE improves the wear resistance by _ folds
8***
Natural Gas
A combustible mixture of hydrocarbon gases
(C4) Pultrusion
A continuous process of making composites with constant cross-section.
Plastic Alloys
A mixture of 2 or more polymers (idea: iron + carbon)
Alloys of PS
Acrylonitrile*** PAN weather resistance Butadiene*** BR Tough and ductile Styrene*** PS stiff rigid transparent ABS*** in between all 3
Aerogels
Aerogel is the lightest and lowest-density solid known to exist with the best thermal insulation property. made from Silica
Carbon fibers are produced through a process called pyrolysis which is a process of ______________.
Heating in the absence of oxygen/ carbonization
RTM Examples
Aircraft Nacelles - fiberglass cloth and polyester resin Truck Top
Addition Polymerization
Also called Chain Growth Involves rapid chain reaction of chemically activated monomers Initiation, growth, termination Ex: PE
Condensation Polymerization
Also called Step Growth Involves individual chemical reactions between pairs of reactive monomers Normally with water by-product A much slower process Ex: phenol formaldehyde (PF)
Vulcanization
Amorphous Thermoplastic Rubber -> Crosslinked Thermosetting Rubber
C6) Vacuum Infusion Molding (VIM)
An alteration of vacuum bagging which uses vacuum to pull in and spread resin.
Which of the following rubbers is air impermeable and used as inner liner for auto tires, basket balls, ...etc?
Butyl Rubber
To further improve rubbers' strength and wear resistance, an additive called ___________is added to rubber to achieve that.
Carbon Black
Additives (Modifiers) for Making Synthetic Rubbers
Carbon black*** - strengthen and impart hardness to rubber
Composites for Aircraft
Commercial aircrafts built from composites such as Boeing 787 and Airbus A350 are 20 to 25 percent more fuel efficient than those made of aluminum alloys.
(O2) Spray-up
Continuous strand glass roving and catalyzed resin are fed thru a chopping gun, which deposits the resin-saturated "chop" on the mold.
Step 2: Cracking
Cracking is the most commonly used process for • making a highly demanded HC from other larger HCs, or • making a monomer from a HC
Fractionating column (tower)
Different hydrocarbons in crude oil have different boiling points due to different molecular sizes, which means they can be separated by distillation.
Neoprene Rubber (Oldest)
Divers suit
Stiffness of Unidirectional Composites
EComposite = EFiber VFiber + EMatrixVMatrix Orthotropic*** Material
(C5) Vacuum Bag Molding
Enclose & seal the part in a plastic bag, then pump vacuum. • Can be applied at the atmospheric pressure or higher pressure condition in an autoclave. It will help to - provide more uniform fiber wetting - remove air voids*** to avoid the development of delamination. - remove excess resin*** to achieve higher fiber/resin ratio (eliminate resin rich regions).
The major raw material for synthetic plastic is _______, and for SYNTHETIC rubber is ________.
Ethylene, Isoprene
ABS
Excellent impact resistance excellent dimensional stability The most commonly used 3D printing material.
Reinforcing Material and Matrix
Fibrous Composite -Carbon Fibers + Epoxy -Glass Fibers + Polyester -Kevlar Fibers + Epoxy Particulate Composite -WC Particles + Co -SiC Particles + Al -Al2O3 Particles + Al
(O3) Filament Winding
Filament winding machine wraps the mandrel with resin- impregnated strands with the required amount and orientation to build the designed reinforced structure.
EVA Applications
Fishing Rod Handles Sandals, Flip Flops Bicycle Saddles Solar Cell Encapsulant
Polyurethane (PUR or PU) Foam
Flotation Sound absorber Thermal insulation
PCB - Printed Circuit Board
Glass Fiber/Epoxy
Wind Turbine Blades
Glass Fiber/Polyester Resin
Most Common Reinforcing Fibers
Glass, Carbon, Aramid (Kevlar) - Glass fiber is the most commonly used.
2. High Density Polyethylene (HDPE)
Grocery & Produce Bags HDPE garbage cart
What is the name of the plastic with recycling resin identification code of 2?
HDPE
What is the typical plastic material for making milk jugs?
HDPE
Molecular Structures of the Most Commonly Used Polymers - PEs
HDPE*** Linear Molecule 4 to 10 short side chains per 1000 C-atoms strongest LDPE*** Long chain branching LLDPE*** Linear Molecule 10 to 35 short side chains per 1000 C-atoms weakest
Matrix Material (Binder)
Holds everything together • Ductile or tough material, transferring load from fiber to fiber
The Size of an UHMWPE Molecule
If the degree of polymerization of an UHMWPE is 250,000 mers, the length of its molecule will be: 0.16 nm x (2 x 250,000) = 80000 nm
A critical process for fiber manufacturing: Cold Drawing***
Improving Fibers' Strength by Further Stretching at T > Tg***
Effect of Degree of Polymerization
Increasing degree of polymerization correlates with higher melting temperature and higher mechanical strength including impact resistant Long-chained polymers cause more entanglement of the chains and thereby increase viscosity
Raw Materials for PMC
Individual Fiber & Matrix Molding Compound (Premixed resin/chopped fibers) Prepreg (premixed resin/fibers at optimal ratio)
Sulfur Vulcanization
It cross-links isoprene molecules to become a thermosetting*** rubber -Increases hardness -Reduces oxidation and reaction with other chemicals -Vulcanization can be accomplished in minutes by adding additives (accelerator and activators)
Crude Oil for Making Monomers
Just need a fraction of the crude oil Ex: C5 to C12 (naphtha fraction for monomers)
4 Polymer Molecular Structures
Linear, Branched (TP) Crosslinked Linear, & Networked (TS)
Natural Rubber (NR)
Liquid resin known as latex which is extracted from the inner soft bark layer After exposure to air, it coagulates and becomes a very soft amorphous thermoplastic To make NR useful, it needs to be converted to a lightly cross-linked thermosetting*** polymer by adding sulfur*** to the heated elastomer, called sulfur vulcanization***.
Mechanical Properties of Rubber
Low stiffness, Low strength, Extremely large % elongation
Characteristics of Engineering Plastics
Mainly utilized for replacing the metallic counterparts - Higher stiffness, strength, toughness and impact resistance - Better creep resistance (better dimensional stability) - High strength and stiffness to weight ratios comparable to most metals
(TP) Blown Film Extrusion
Making Plastic Sheets & Films annular die 1. Extruder 2. Blowing the film with air-cooled ring 3. Measuring unit 4. Thickness measuring unit 5. Clamping unit 6. Turning unit 7. Winding up 8. Automation
How synthetic fibers are made?
Melted plastic (or melt) extruded from a spinneret Speeds of up to 42 feet/second
Paraffins
Methane-CH4 Ethane-C2H6 Propane-C3H8
Polyimide (PI, Kapton)
Most heat resistant plastic - withstand ≥ 400C
What kinds of rubbers are used in the auto tires?
NR SBR BR
Olefins
Olefins - synthetic monomers mainly for plastics - are unsaturated hydrocarbons containing one double C=C bond - e.g., ethylene (C2H4), propylene (C3H6), butylene (C4H8),
Composites Manufacturing Processes
Open Molding: laminate is exposed to the atmosphere during the fabrication process Closed Molding: the composite is processed in a two-sided mold set, or within a vacuum bag
Which of the following is a typical material for making green house panels as an alternative to glass:
PC
What is the typical plastic material for making drinking-water or soft drink bottles?
PET
1. Polyethylene Terephthalate (PET)
PET Bottles BOPET*** Film - (Biaxially Oriented PET Film) Polyester Pillow Filler Polyester Fiber
What is the name of the plastic with recycling resin identification code of 1?
PETE
The polymer which is used to make Plexiglass is ___________.
PMMA
6. Polystyrene (PS)
PS Panel (HIPS) + PUR Back Foaming
Which of the following polymers does not contain hydrogen?
PTFE (Teflon)
The typical material for making plastic floor tiles, water pipes, home exterior sidings, garden hoses, and your credit cards is ______________.
PVC
Saturated HCs (Single C-C bond) 75%
Paraffins (25%) Saturated Chains Naphthenes (Cycloparaffins) 50% Saturated Rings
3. Polyvinyl Chloride (PVC)
Plasticiser
Three Most Commonly Used Synthetic Fibers
Polyester (or polyethylene terephthalate (PET) fibers) Polyamide (PA, used for aramid*** fibers which is a family of nylons (1938), including Nomex® (1963) and Kevlar® Polyacrylonitrile (PAN, aka acrylic fibers
Synthetic Rubbers (All Thermosets)
Polyisoprene (IR) - the Synthetic NR Butadiene Rubber (BR) Nitrile Rubber (NBR,Buna-N) Styrene Butadiene Rubber (SBR) Chloroprene/Neoprene Rubber (CR) Silicone Rubber (SI) Butyl Rubber (IIR) Polyurethane Rubber (PU, PUR) EPDM Rubber (EPDM)
(TS) Reaction Injection Molding
Polymerization***, cross-linking***, and formation of the part*** take place in the mold simultaneously
(C3) Resin Transfer Molding (RTM)
Polymerization, cross-linking, and formation of the part take place in the mold simultaneously under heat and pressure.
Homopolymers
Polymers formed with only 1 type of monomers - e.g., PS (styrene), PE (ethylene), PP (propylene), and PVC (vinyl chloride)
Thermoplastic Polymers
Polymers that can be repeatedly melted to a liquid, reshaped, and cooled to a solid; thus making them recyclable. (Examples: PE, PP, PS, Nylon, ABS...) Primary and secondary bonds
Thermosetting Polymers
Polymers that form irreversible covalent bonds during the curing (hardening) process, which will chemically deteriorate when subjected to high heat; thus they can not be remelted and reshaped, and are not recyclable. (Example: Rubbers, PF, Polyurethane) All primary bonds
Polyurethane Rubber (PU, PUR)
Polyurethane Rubber (PU, PUR)
Step 2 for production of Polymers from Crude Oil
Production of monomers with Cracking process
Step 1 for production of Polymers from Crude Oil
Production of needed HCs with Fractional Distillation
Step 3 for production of Polymers from Crude Oil
Production of polymers with Polymerization process
Effects of Carbon Black Filler in Rubber
Pure SBR: Tensile strength = 2.5MPa; no abrasion resistance (will flake under rubbing) • After SBR mixed with 50% of its weight of various carbon black: (i.e., SBR:C = 2:1)
Structure of Composites
Reinforcing Material (filler) - dispersed phase Matrix (binder) - continuous phase Most Common Types: Fibrous*** & Particulate***
Considering only the rubber component, an auto tire sold in a store is a piece of ___________ rubbers.
SBR (Butadiene Rubber)
4. Low Density Polyethylene (LDPE)
Sandwich bag
Step 1: Fractional Distillation
Separate crude oil into various hydrocarbon fractions
Polycarbonate (PC, Lexan)
Shaterproof car lights
2. MoldingCompound (For In-house Consumption)
Sheet Molding Compound (SMC) - Premixed material of short fibers preimpregnated with resin, catalyst, fillers, and additives into a continuous sheet form Bulk Molding Compound (BMC) or Dough Molding Compound (DMC) - Premixed material of short fibers impregnated with resin, catalyst, fillers, and additives, which has no specific form and looks like a paste
Which elastomer is most suitable for medical applications?
Silicone Rubber
Inorganic Polymer: Silicone Rubber
Silicone elastomers exhibit the widest operating temperature range (-100 to 316C) of any elastomer. Silicones can be supplied as liquids, gels, and solid rubber products (sheets, extruded or molded profiles, etc.) Medical applications (minimal reactivity w body)
Plastics with lowest coefficient of friction in order
Teflon, UHMWPE, POM (Acetal, Delrin), HDPE important for bearings and gears
Glass Transition Temperature , Tg
Tg is defined as the critical temperature of an amorphous material at which the material changes its behavior from being 'glassy' (hard, brittle) to being 'rubbery' (viscoelastic, flexible). Only amorphous*** material (glass) and semicrystalline*** materials (polymers) have this property of glass transition temperature.
Military Aircraft
The F-22 Raptor uses composites for more than 1/3 of its structure. PI*** Resin
degree of branching
The more branched a polymer chain, the lower its tensile strength, crystallinity, and density.
Ethylene***
The most important monomer
(TP or TS) Foaming
The plastic becomes very soft and the sodium bicarbonate gives off carbon dioxide gas that forms small bubbles. The plastic expands and the bubbles remain when the plastic is cooled
(TP) Profile Extrusion
The plastic pellets (or granules) is placed in a hopper and then falls into the machine. The shape and size of the extrusion is the same as the shape and size of the hole in the die.
How do we make carbon fibers?
The principal precursor material: - Polyacrylonitrile (PAN***) o Also called "acrylic" fibers Method of production: - A polymer fiber undergoes pyrolysis*** under well-controlled heat, timing, and atmospheric conditions. At some point in the process, the fiber is subjected to tension. - Pyrolysis is the chemical decomposition of organic materials by heating in the absence of oxygen***.
Polystyrene (PS) Foam - Styrofoam®
Thermal Insulation Packaging Flotation
Phenol formaldehyde which is a _______ polymer was used in your lab to make coasters using a method called _______.
Thermosetting, Compression Molding
(C1) Compression Molding
This part is made out of a skirts sheet molding compound.
5. Polypropylene (PP)
Tupperware BOPP*** film
(TP) Sheet Extrusion
Typically, thickness of 0.5 to 25 mm, and widths of 2 to 9 meters
Which polymer has the highest impact strength among those tested in lab?
UHMWPE
As part of the sun rays, ___________ will damage polymers due to the energy it carries is strong enough to break the bonds of polymer chains after long term exposure.
UV Rays
Rubber Aging - Weather Cracking
UV light and heat
Typical Structures of Elastomers
Undeformed Stretched (linear)
Comparison of Specific Strength for Various Composites
Unidirectional Composites 4-5 times that of metals Quasi-isotropic Composite 2 times that of metals
Autoclave Curing Chamber
Used for curing vacuum bag molded composite structures - Filament-wound structures - Manual lay-ups (or Machine assisted lay-ups) • Controlled heating cycles under pressure • Parts sealed in vacuum bag
(C2) Reinforced Reaction Injection Molding (RRIM)
Using milled or chopped fibers
Elements for Better Quality Composites
Vacuum, High Pressure, and Heat
_________ is a process to strengthen rubber by adding _______ to transform it into a thermosetting elastomer.
Vulcanization, Sulfur
Other Usages of (Liquid) Silicone
Water Repellant Liquid or gel lubricant - Ideal for surfaces like rubber and plastics, where petroleum products cannot be used.
(O1) Hand Lay-Up
Wet Lay-Up: - Reinforcing material such as chopped strand mat, woven, knitted, or textile fabric is positioned manually in the open mold and resin is poured, brushed, or sprayed over for each layer Prepreg Lay-Up: - Reinforcing material is pre-coated with resin and no further application of resin is required
Crystallinity of Polymers
When polymer chains (molecules) are arranged in a neat orderly manner Otherwise, we say the polymer is amorphous. In real life, polymers are semi-crystalline*** to varying degrees.
Reasons that Composites Reduce Weight
a) Better strength/stiffness to weight ratio, resulting in light weight • Specific Strength = Tensile Strength/Density • Specific Modulus = Modulus/Density b) Material's property can be tailored
Crosslinked Linear
adjacent linear chains are joined one to another at various positions by covalent bonds. Characteristic of thermosetting*** plastic such as rubbers.
Degree of polymerization
average*** number (N) of repeating mers in a polymer molecule (or chain). N = 100-2000*** for typical commercial polymers For UHMWPE*** (ultra high molecular weight polyethylene), the degree of polymerization may be 100,000 to 250,000 or more.
Copolymers
e.g., SBR rubber (styrene + butadiene), ABS plastics (acrylonitrile + butadiene + styrene), PET
Polytetrafluoroethylene (PTFE, Teflon)
electric insulator water barrier
Foam Plastics
gas or air entrapped in the polymer resins to reduce the density of the material 1. Open cell Flexible 2. Closed cell Rigid Most common: - Polystyrene (PS) (e.g., styrofoam) - Polyurethane (PUR or PU) (e.g., spray foam) - Polyethylene (LDPE)
Networked
having both branching & crosslinking occurred in a polymer, characteristic of thermosets*** such as epoxy, phenol-formaldehyde.
Polymerization
process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks of polymer chains, polymers
Crude Oil (Hydrocarbons)
rude oil is a mixture of HCs of various molecular sizes
Branched
side-branch chains are connected to the main ones. Branching can be achieved by numerous techniques, it sometimes occurs spontaneously during synthesis of polymers. (structure of a thermoplastic)
PU (PUR) and PVC Synthetic Leather
sports balls
Polyamide (PA, Nylon)
strongest plastic
polymer
substance composed of molecules with large molecular mass made up of repeating structural units, or monomers, connected by covalent chemical bonds
Dienes (diolefins)
ynthetic monomers for rubbers - are unsaturated HCs containing two double C=C bonds. - Butadiene (C4H6), isoprene (C5H8)
Reinforcing Material (Filler)
• Embedded in the matrix phase • Strong material, primary load carrier • In the form of particles, fibers ,or sheets
Thermoplastic Rubbers
• Ethylene Vinyl Acetate (EVA) • Styrene-Butadiene-Styrene (SBS) shoe soles, tire treads, molding parts • Styrene-Isoprene-Styrene (SIS) hot-melt glues • Recyclable
Thermosets
• Phenolics (PF) • Amino Plastics (UF, MF) • Unsaturated*** Polyesters (UP) • Vinyl Esters (VE) • Epoxies (EP) • Thermoset Polyimides (PI) • Polyurethane (PU or PUR)
