What type of structure does poly have?
Polymers have very large molecules . The atoms in a polymer molecule are joined together by strong covalent bonds in long chains. There are variable numbers of atoms in the chains of a given polymer. One example of a polymer is poly(ethene).
How is polyethylene formed GCSE?
When alkenes join together to form a polymer with no other substance being produced in the reaction, the process is called addition polymerisation. Plastics are polymers and are made by polymerisation. Example: poly(ethene) (often called polythene) is made by polymerising the simplest alkene, ethene.
What are the structures and properties of polymers?
Polymers always have at least two phases namely, amorphous and crystalline. It is not its Tg, but rather its crystallinity that determines whether the material is a plastic or rubber. The crystals (hard phases) and rubbery (soft phases) make the PE behave as a plastic with toughness, and not as a rubber.
What are the properties and uses of Polyethene?
Low-density polyethylene Its melting point is approximately 110 °C (230 °F). Principal uses are in packaging film, trash and grocery bags, agricultural mulch, wire and cable insulation, squeeze bottles, toys, and housewares.
Is polypropylene a simple molecular structure?
Polypropylene is part of a greater group of materials known as polymers. A polymer is a great molecule composed of many simple chemical units generally called structural units or monomers. Polypropylene is one of the most versatile thermoplastic polymers in the market.
What is polymeric structure?
2.2 Polymer Structure. The polymer molecule consists of a “skeleton” (which may be a linear or branched chain or a network structure) and peripheral atoms or atom groups. Polymers of a finite size contain so-called end groups, which do not form part of the repeating structure proper.
How is plastic made GCSE?
Polymerisation process Some small molecules, called monomers, can join together to make very long molecules, called polymers – this process is called polymerisation. Many polymers are made from chemicals obtained from crude oil, eg molecules of ethane can join together to make polythene.
What are polymers GCSE?
Polymers are very large molecules made when many smaller molecules join together, end to end. The smaller molecules are called monomers. In general: lots of monomer molecules → a polymer molecule.
What are 2 structures of polymers?
The four basic polymer structures are linear, branched, crosslinked, and networked. Diagrams of linear, branched, crosslinked, and networked polymer structures.
What is difference between polyethylene and polypropylene?
Polypropylene is not as sturdy as polyethylene. Polypropylene is stiffer and resistant to chemicals and organic solvents compared to polyethylene. Polypropylene is pure, non-stretching and generally more rigid than polyethylene.
How does a polyethylene plant work?
This film is used for packaging and making plastic bags. Polyethylene is derived from either modifying natural gas (a methane, ethane, propane mix) or from the catalytic cracking of crude oil into gasoline. In a highly purified form, it is piped directly from the refinery to a separate polymerisation plant.
What is the structure of polypropylene?
(C3H6)nPolypropylene / Formula
How is polypropylene made?
Generally, polypropylene is produced via a chain-growth polymerization reaction involving propylene. This polymer is known to be a thermoplastic polymer, i.e. it softens upon heating and can, therefore, be remoulded.
How strong is polypropylene?
Compared to many materials, polypropylene’s structure has a good tensile strength—somewhere around 4,800 psi. This allows the material to withstand fairly heavy loads, despite being lightweight.
What is the chemical formula of polypropylene?
Polypropylene is a polymer whose monomer is propylene (an organic hydrocarbon with the chemical formula C 3 H 6 ). The chemical formula of polypropylene is (C 3 H 6) n. This polymer is also known as polypropene and is often denoted by the abbreviation ‘PP’.
What are the basic chain structures of polypropylene (PP)?
Upon polymerization, PP can form three basic chain structures depending on the position of the methyl groups: Atactic (aPP) – Irregular methyl group (CH 3) arrangement Isotactic (iPP) – Methyl groups (CH 3) arranged on one side of the carbon chain Syndiotactic (sPP) – Alternating methyl group (CH 3) arrangement