Materials - Plastics

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What are plastics?
Plastics are organic, all based on carbon with synthetic plastics made from crude oil with monomer building blocks polymerised to make polymers. Additives make polymers plastics.
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What is electronegativity?
Electronegativity - ability to attract electronics. C,H, N, O, P and S all polymers with electronegativity around 2.5. Difference in electronegativity (large=ionic bonds), (small=covalent
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What is crude oil made of?
Polymers made from 100% covalent C-C bonds. Crude oil made from hydrocarbons (aliphatics C1-C60, aromatics C6H5, naphthenes (cycloalkanes, monocyclic rings with C-C bonds). Nonhydrocarbons: <8% S, <1% N, <3% O, metallics 100ppm
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What are homologous polymers?
Polymers can be homologous where they have the same components in bonding
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How do unbranched alkane boiling points compare to branched?
Unbranched alkanes have greater boiling point than branched due to a greater surface area
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What are the temperatures for fractional distillation of crude oil products?
20 degrees, petroleum gas, 150- gasoline, 200 - kerosene, 300 - diesel, 370- industrial fuel oil, 400 - lubricating oil, paraffin wax, asphalt
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What are examples of alkanes, aromatics, cycloalkanes, alkenes, and alkynes?
Alkanes: methane, ethane, propane, butane etc, aromatics: Benzene, napthalene, cycloalkanes : Cyclohexane, alkenes: ethylene, butene etc, (double bond, more reactive), alkynes (acetylene) - unsaturated, double bond
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What are petrochemical feedstocks? What is peak oil?
Petrochemical feedstocks are made for manufacturing polymers. Peak oil is idea that oil is a finite reserve
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How does polymerisation of ethylene work?
Ethylene (n*A)-> heat, pressure, catalyst -> polyethylene (An) - C=C bonds become C-C
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How do molecular weight and amount of polymer vary in crude oil?
In crude oil, molecular weight and amount of polymer vary, with amount of polymer (y) increasing with molecular weight then dropping. There's a chain size average and weight average. Weight depends on conditions of distillation.
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What are different types of crystal phase?
Polyethylene has cystalline and amorphous regions, semi-crystalline. Polymers can be crystalline or amorphous. Crystal phase affects properties
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What are thermosets and thermoplastics?
Thermoplastics soften and melt when heated, can be moulded into new shape and reheated/moulded many times. Thermosets set when first cooled and won't soften when reheated, damage when heated too much.
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What is thermoplastic bonding?
Thermoplastics such as polyethylene, polystyrene etc are held by weak intermolecular bonding, side chains reduce density as distance to main C-C chain increased and intermolecular attraction falls
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What are bonds in thermosets like?
Thermosets like bakelite, epoxy resins, and polyester are held by strong covalent bonds. Initial heating causes polymer to undergo chemical reaction that locks monomer chains. More heating destroys bonds like cross links
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What are copolymers?
Copolymers made from different types of polymer. There's random, alternating (one polymer then next continuously), blocked (one group of polymers then next in line), and grafted (different polymers on side chains)
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What are syndiotactic and actactic arrangements in polystyrene?
Syndiotactic - regular side chains allows crystalline structure, actactic - side chains not regular, less crystalline
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What are polymer properties?
Combustible, low bp/mp, low water solubility, high molecular weight, variable molecular size, low compressive strength/stiffness, high toughness, low density, durable, low thermal conductivity, electrical insulators, low permeability, ease of process
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What is ideal ductile behaviour in polymers?
Hard and tough behaviour is ideal
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How is plastic industry doing?
300 million tonnes per year of plastics made, 1/3 for packaging, 1/4 for construction, also use in electronic goods, vehicles, foam insulators, etc
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What are different high vol plastics used for?
Polyethylene (containers, pipes, landfill liners etc), PVC (window frames, pipe, flooring), polypropylene (pp - films, fibres, etc), polystyrene (PS- packaging, thermal insulation), PET bottles,film, PU - adhesive, trainer soles, ABS - weather sheet,
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What is needed with polymers for plastics?
Additives make plastic: plasticisers, fillers, antioxidants, pigments.
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What is extrusion process? (for pipes)
Extrusion involves polymer granulate entering hopper, being heated and pressurised, then being extruded as wire.
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What are injection and compression moulding?
Ram pushes screw and barrel, hopper passes polymer to heaters which passes nozzle and enters mold. Compression moulding - Thermosets/thermoplastics compressed in mold
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What is the main plastic used in Civ Eng?
PVC is main plastic for construction/building, accounts for >50% plastic used in Western europe, half for construction plastics and pipes, 30% insulators, rest for window/floor cover
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How is HDPE and LDPE used in Civ Eng?
LDPE forms flexible membrane liners above venting sand, graded fill and waste. HDPE used in pipes
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What are properties of bitumen?
Bitumen viscous, formed from crude oil polycyclic aromatic hydrocarbons. Heaviest oil fraction with highest mp, thermoplastic, good water proofing / adhesive and can be found in oil sands. Mostly C,H,O,S,N and organic salt metal traces
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How does bitumen filling affect asphalt properties?
Low asphalt filling, bitumen acts as a binder and aggregate main property determiners, almost filled - stone and bitumen contribute to properties, need compacting, volume of bitumen>solids - bitumen dominates. Used in asphalt road surface and paving
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What are main components of bitumen?
Asphaltenes and maltenes (saturates, resins, aromatics)
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Other cards in this set

Card 2

Front

What is electronegativity?

Back

Electronegativity - ability to attract electronics. C,H, N, O, P and S all polymers with electronegativity around 2.5. Difference in electronegativity (large=ionic bonds), (small=covalent

Card 3

Front

What is crude oil made of?

Back

Preview of the front of card 3

Card 4

Front

What are homologous polymers?

Back

Preview of the front of card 4

Card 5

Front

How do unbranched alkane boiling points compare to branched?

Back

Preview of the front of card 5
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