1 / 26

www.tradenote.net

ENMAT101A Engineering Materials and Processes Associate Degree of Applied Engineering (Renewable Energy Technologies) Lecture 19 – Plastics materials and rubbers. www.tradenote.net. Plastics materials and rubbers. EMMAT101A Engineering Materials and Processes.

duc
Download Presentation

www.tradenote.net

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ENMAT101A Engineering Materials and ProcessesAssociate Degree of Applied Engineering (Renewable Energy Technologies)Lecture 19 – Plastics materials and rubbers www.tradenote.net

  2. Plastics materials and rubbers EMMAT101A Engineering Materials and Processes

  3. Plastics materials and rubbers Note: This lecture closely follows text (Higgins Ch19) Geomembrane liner: http://www.fabtech.com.au EMMAT101A Engineering Materials and Processes

  4. 19.2 Types of plastics (Higgins 19.2) READ HIGGINS Ch19.2 Thermoplastic materials, Thermosetting materials, Elastomers 19.2.1 Raw materials 19.2.2 Composition of plastics EMMAT101A Engineering Materials and Processes

  5. 19.2 Types of plastics (Higgins 19.2) (i) Linear polymers: These are polymers in which monomeric units are linked together to form linear chain. Tend to pack well and have high intermolecular forces of attraction, giving high densities, high tensile strength and high melting points. Some common example of linear polymers are HDPE, nylon, polyester, PVC, PAN, PS, PMMA. PTFE etc. (ii) Branched chain polymers: These are polymers with side chains or branches of different lengths. These cause irregular packing and therefore, they have low tensile strength, low density, boiling point and melting points thancomparable linear polymers. Examples include low density polythene, modified linear polymers. http://www.lbl.gov/MicroWorlds/Kevlar/KevClue1Act1.html http://courses.chem.psu.edu/chem112/materials/polymers.html EMMAT101A Engineering Materials and Processes

  6. Alkanes Covalent bonding of C atoms with H atoms. The most basic type of hydro-carbon, usually derived from fossil fuels (esp crude oil). They all burn with oxygen to produce C02 + water. Bio-fuel (ethanol) is an alcohol, so it has oxygen in it. http://www.3rd1000.com Ethanol above Oil refinery right Wikipedia EMMAT101A Engineering Materials and Processes

  7. Alkanes Increasingmolecule size. Gas has 1 to 4 C. Petrol contains 5 to 12 C. Wikipedia EMMAT101A Engineering Materials and Processes

  8. Alkanes Increasing molecule size increases boiling point and viscosity (thickness or resistance to flow). Eventually you get wax at a few hundred C atoms. Then, at about 1200 C atoms, you have plastic: Polyethylene. http://www.3rd1000.com EMMAT101A Engineering Materials and Processes

  9. Plastics Unlike metals where the outer-shell electrons can travel freely, the outer-shell electrons in covalently bonded substances (like plastics) are securely held to the atoms and cannot move away. So they make great electric insulators. Polyethene was first used as an electrical insulator in electronics equipment used in radar during the Second World War. Higgins 1.4.4 Fig 1.7 Why is it called Polyethylene? Poly-mer means “Many”– “mers”. In the case of Poly-ethylene, the mer (or base unit) looks like methane. The original name given in 1898 was polymethylene. However, it is made from polymerization of ethylene – which is a gas. HDPE bin bcsplastics.com.au EMMAT101A Engineering Materials and Processes

  10. Van der Waals Forces Why do the alkanes get stiffer as the molecules get longer until eventually becoming a solid? The molecules are held together by weak electrical imbalances in adjacent molecules (caused by electron distribution). These forces are too weak to hold short molecules together, but when there are hundreds of Carbon atoms in the chains, the Van der Waal molecular forces increase. This is why HDPE (garbage bin) is harder than LDPE (squeeze bottle). LDPE bottle promotionsonly.com.au HDPE bin bcsplastics.com.au EMMAT101A Engineering Materials and Processes

  11. Gecko feet Biomimicry is when engineers copy ideas from nature. Velcro was copied from seed burrs in 1948. Today we are trying to copy the feet of the gecko because they stick to anything – even glass, but not by suction. The gecko can stick to any smooth surface and also friable sandstone. A gecko can hold it’s entire weight on one toe. http://www.sfu.ca No hooks, no slime, no suction. EMMAT101A Engineering Materials and Processes

  12. Gecko feet. Van der Waals Forces! The secret of the Gecko’s grip is Van der Waal’s forces. The forces are weak, but with enough surface area they become substantial. Wikipedia/CC BY 1.0 The surface area is achieved by splitting the toes into smaller and smaller hairs – until there is about a billion hairs of nanometer size. EMMAT101A Engineering Materials and Processes

  13. Copying Gecko feet. Velcro to Anything! Researchers have developed a robot that can climb vertical surfaces. Other teams are making gecko tape that sticks like 1 sided Velcro. http://www.sfu.ca Sticky gecko feet Space Age Reptiles BBC animals 2:25 min Gecko Tape: http://news.sciencemag.org EMMAT101A Engineering Materials and Processes

  14. 19.2 Types of plastics (Higgins 19.2) READ HIGGINS Ch19.2 Thermoplastic materials, Thermosetting materials, Elastomers 19.2.1 Raw materials 19.2.2 Composition of plastics 19.2.3 General properties of plastics materials Resist atmospheric corrosion Lightweight Reasonably tough and strong Cannot handle much heat Good finish, colours, some transparent Easy to process http://www.dotmar.com.au EMMAT101A Engineering Materials and Processes

  15. 19.3 Thermoplastics (Higgins 19.3) READ HIGGINS Ch19.3 19.3.1 Plasticisers Plasticised PVC cable: www.diytrade.com Rigid PVC pipe: Wikipedia EMMAT101A Engineering Materials and Processes

  16. 19.4 Thermoplastic materials (Higgins 19.4) READ HIGGINS Ch19.4 19.4.1 Vinyl plastics Polyethylene (PE) Polyvinyl chloride (PVC) Polyvinyl acetate (PVA) Polyvinyl acetate/chloride copolymers Polyethylene-vinyl acetate (EVA) Polypropylene (PP) Polypropylene-ethylene copolymers Polystyrene (PS) Acrylonitrile-butadiene-styrene (ABS) PVC boat: Wikipedia EMMAT101A Engineering Materials and Processes

  17. 19.4 Thermoplastic materials (Higgins 19.4) READ HIGGINS Ch19.4 19.4.2 Fluorocarbons 19.4.3 Cellulose-base plastics (cellulose esters) 19.4.4 Polyamides (PA) 19.4.5 Polyesters 19.4.6 Polyacetals 19.4.7 Acrylics 19.4.8 High-temperature thermoplastics Polyimides, Polysulphones, Polyether ether ketone (PEEK), http://www.dotmar.com.au EMMAT101A Engineering Materials and Processes

  18. 19.5 Thermosets(Higgins 19.5) READ HIGGINS Ch19.5 Headlamp Housing http://www.withermoset.com EMMAT101A Engineering Materials and Processes

  19. 19.6 Thermoset Materials (Higgins 19.6) READ HIGGINS Ch19.6 19.6.1 Phenolics Phenol formaldehyde (PF) Urea formaldehyde (UF) Melamine formaldehyde (MF) 19.6.2 Polyester resins 19.6.3 Polyurethanes 19.6.4 Epoxy resins 19.6.5 Polyimides 19.6.6 Silicones http://en.wikipedia.org/wiki/Silicone http://www.glowpaint.com.au EMMAT101A Engineering Materials and Processes

  20. 19.7 Elastomers(Higgins 19.7) READ HIGGINS Ch19.7 19.7.1 Long chain molecules in rubber 19.7.2 Vulcanisation 19.7.3 Engineering elastomers Natural rubber (NR) and polyisoprene (IR) Styrene-butadiene rubber (SBR) Butadiene rubber (BR) Polychloroprene rubber (CR) Acrylonitrile-butadiene rubbers (NBR) Butyl rubber (IIR) Ethylene-propylene rubber (EPM) Silicone rubbers (SI) news.alibaba.com news.alibaba.com EMMAT101A Engineering Materials and Processes

  21. Recycling of plastics Plastic recycling Only thermoplastics can be re-melted. Identification is needed to prevent mixing. Food grade must be virgin (new) – not recycled material. Common plastics can be collected (PET), but specialist polymers are too rare. Product must be simple enough to sort. Recycling Misconceptions: http://www.ecologycenter.org/ptf/misconceptions.html Recycled Polyethylene: http://www.replas.com.au PET: wikipedia EMMAT101A Engineering Materials and Processes

  22. Recycling of plastics Plastic recycling http://learneasy.info/MDME/MEMmods/MEM30007A/polymers/polymers.html EMMAT101A Engineering Materials and Processes

  23. Resources. Polymers Wikipedia: Plastic EMMAT101A Engineering Materials and Processes

  24. Online Resources. http://www.dotmar.com.au/engineered-plastics-products.html http://www.adelaideplastics.com.au/glossary.htm EMMAT101A Engineering Materials and Processes

  25. Glossary Polymer Monomer Polymerisation Thermoplastic Thermosetting Elastomer Copolymer Cross linking Vulcanisation Branched polymer Mer Molecular weight EMMAT101A Engineering Materials and Processes

  26. QUESTIONS Higgins Ch19: Callister Ch4 Moodle XML: Some questions in 10104 Polymers • Define all glossary terms. • Attempt relevant questions from Quiz 10104 Polymers • Which elastomer is used for car tyres? What are the strong and weak points of this polymer? • Explain the different uses of the terms vulcanisation and cross-linking. • Using their molecular features, explain the physical differences in the range of polyethylenes. What type of molecular force is responsible for this change? • Make comparisons of thermoplastic and thermosetting polymers (a) on the basis of mechanical characteristics upon heating, and (b) according to possible molecular structures. • Some of the polyesters may be either thermoplastic or thermosetting. Suggest one reason for this. • (a) Is it possible to grind up and reuse phenol- formaldehyde? Why or why not? (b) Is it possible to grind up and reuse polypropylene? Why or why not? • Compare the general properties of the four classes of polymeric structures: Linear, branched, cross-linked and network. Gives 2 examples in each type. EMMAT101A Engineering Materials and Processes

More Related