TAFE NSW -Technical and Further Education Commission ENMAT101A Engineering Materials and Processes Associate Degree of Applied Engineering (Renewable Energy Technologies) Lecture 20 – Properties of plastics

TAFE NSW -Technical and Further Education Commission Properties of plastics EMMAT101A Engineering Materials and Processes Reference TextSection Higgins RA & Bolton, Materials for Engineers and Technicians, 5th ed, Butterworth Heinemann Ch 20 Reference TextSection Callister, W. Jr. and Rethwisch, D., 2010, Materials Science and Engineering: An Introduction, 8th Ed, Wiley, New York. Ch 4

TAFE NSW -Technical and Further Education Commission Properties of plastics EMMAT101A Engineering Materials and Processes Note: This lecture closely follows text (Higgins Ch20) Blowmoulded Polycarbonate

TAFE NSW -Technical and Further Education Commission 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. EMMAT101A Engineering Materials and Processes LDPE bottle promotionsonly.com.au HDPE bin bcsplastics.com.au This is why HDPE (garbage bin) is harder than LDPE (squeeze bottle).

TAFE NSW -Technical and Further Education Commission 20.2 Crystal and glass states (Higgins 20.2) EMMAT101A Engineering Materials and Processes READ HIGGINS Ch20.2 In thermoplastics materials, these molecules are attracted to each other by relatively weak van der Waals forces, whilst in thermosetting plastics they are joined to each other by strong, permanent covalent bonds Melting points of polymers Glass transition temperature Vicat softening temperature Higgins Wikipedia/CC BY 1.0

TAFE NSW -Technical and Further Education Commission 20.2 Crystal and glass states (Higgins 20.2) EMMAT101A Engineering Materials and Processes Amorphous / crystalline structures of Thermoplastics Periodic Table of Polymers Reduced version of Periodic Table of Polymers Periodic Table of Polymers Reduced version of Periodic Table of Polymers Copyright: Tangram Technology Ltd. ( The table may be freely reproduced provided full acknowledgement of the copyright is given.

TAFE NSW -Technical and Further Education Commission 20.3 Mechanical properties (Higgins 20.3) EMMAT101A Engineering Materials and Processes (i) Low elastic modulus, low yield stress, e.g. PVA and PTFE. (ii) High elastic modulus, low elongation, e.g. PF, PMMA and PS. (iii) Low elastic modulus, low yield stress but high elongation and high stress at break, e.g. PE and plasticised PVC. Higgins

TAFE NSW -Technical and Further Education Commission 20.3 Mechanical properties (Higgins 20.3) EMMAT101A Engineering Materials and Processes (iv) High elastic modulus, high yield stress, high tensile strength and low elongation, e.g. rigid PVC and modified PS. (v) High elastic modulus, high yield stress, high tensile strength and high elongation, e.g. nylons and polycarbonates, Higgins (vi) Very low elastic modulus, low yield stress and low tensile strength but very high elastic elongation, e.g. natural rubber and other elastomers.

TAFE NSW -Technical and Further Education Commission 20.3 Mechanical properties (Higgins 20.3) EMMAT101A Engineering Materials and Processes Higgins

TAFE NSW -Technical and Further Education Commission 20.3 Mechanical properties (Higgins 20.3) EMMAT101A Engineering Materials and Processes 1 Bond bending of the carbon-carbon covalent bonds in the polymer chain - this is manifested as the ordinary elasticity and is an instantaneous deformation. 2 Uncoiling of the polymer chains - this gives rise to high elasticity and is very time dependent. 3 Slipping of polymer chains past each other - this produces irreversible plastic flow and is also very time dependent.

TAFE NSW -Technical and Further Education Commission 20.3 Mechanical properties (Higgins 20.3) EMMAT101A Engineering Materials and Processes Higgins

TAFE NSW -Technical and Further Education Commission 20.3 Mechanical properties (Higgins 20.3) EMMAT101A Engineering Materials and Processes Higgins

TAFE NSW -Technical and Further Education Commission 20.3 Mechanical properties (Higgins 20.3) EMMAT101A Engineering Materials and Processes Hardness tests Higgins

TAFE NSW -Technical and Further Education Commission 20.3 Mechanical properties (Higgins 20.3) EMMAT101A Engineering Materials and Processes Impact tests Higgins

TAFE NSW -Technical and Further Education Commission 20.3 Mechanical properties (Higgins 20.3) EMMAT101A Engineering Materials and Processes Creep Higgins

TAFE NSW -Technical and Further Education Commission 20.3 Mechanical properties (Higgins 20.3) EMMAT101A Engineering Materials and Processes Other mechanical tests Higgins

TAFE NSW -Technical and Further Education Commission 20.4 Additives (Higgins 20.4) EMMAT101A Engineering Materials and Processes Fillers Anti-static agents Flame retardants Friction modifiers Other additives Foamed or 'expanded' plastics materials Higgins

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes Calendering Higgins Calandered PVC fabric: Wikipedia

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes 20.S.2 Extrusion Higgins Extruded Plasticised PVC cable:

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes Moulding Compression-moulding (Figure 20.11) Higgins Compression Moulded Rubber Tyres news.alibaba.com

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes Injection-moulding (Figure 20.12) Higgins PP crate

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes Transfer-moulding (Figure 20.13) Higgins Thermosets: sinotech.com

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes Blow moulding (Figure 20.14) Higgins PE bottle:

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes Blow moulding by preform (PET) PET bottles: Injection Moulded Preform: Blow Moulding explanation x

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes Film-blowing (Figure 20.15) Bags? For making film too. Higgins Plastic bag recycling?

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes Vacuum-forming (Figure 20.16) Higgins Wikipedia

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes Casting Slush-moulding Dip moulding Roto Moulding Dip Moulding: Roto Moulded 34 kL Polyethylene Tank

TAFE NSW -Technical and Further Education Commission 20.5 Shaping plastics (Higgins 20.5) EMMAT101A Engineering Materials and Processes Other: Machining Machined Acrylic

TAFE NSW -Technical and Further Education Commission EMMAT101A Engineering Materials and Processes Videos: 1.Plastics in manufacturing [videorecording] Davis, John. Warriewood, NSW : Classroom Video, c videodisc (21 min.) : sd., col. ; 4 3/4 in. + teacher's notes. Explains injection moulding, rotational moulding, and vacuum and pressure forming of plastic products. DVD /PLAS /PLAS 2. Forming of plastics. Part A [videorecording] Scutt, Don. Chadstone, Vic. : Double D Technical Productions, c videodisc (29 min.) : sd., col. ; 4 3/4 in. This video examines compression and injection moulding of thermosetting materials, physical properties of polymers and how these vary with temperature changes, compounding, extrusion of sheet tube, cross head and co extrusion, blow moulding, blown film and printing, production of fibres and printing on plastics. DVD /FORM PART A /FORM PART A 3. Forming of plastics. Part B [videorecording] Scutt, Don. Chadstone, Vic. : Double D Technical Productions, c videodisc (29 min.) : sd., col. ; 4 3/4 in. This video examines the injection moulding process for a range of products, injection blow moulding, using preforms, production of flexible foams, rotational moulding, extrusion compression moulding, thermoforming and the computer modelling and production of stadium seat. DVD /FORM PART B /FORM PART B

TAFE NSW -Technical and Further Education Commission EMMAT101A Engineering Materials and Processes Wikipedia: Plastic Resources. Polymers

TAFE NSW -Technical and Further Education Commission Glossary EMMAT101A Engineering Materials and Processes Compounding Extrusion Cross head and co extrusion Blow moulding Blown film Printing on plastics Production of fibres Injection blow moulding Preforms Flexible foams Rotational moulding Extrusion compression moulding Thermoforming Injection moulding Vacuum and pressure forming

TAFE NSW -Technical and Further Education Commission QUESTIONS Higgins Ch20 Moodle XML: Polymers 1.Complete Quiz Polymers 2.Explain what crystallinity means in polymers. Outline the effects of increasing crystallinity in thermoplastic polymers. 3.Describe the differences between blow moulding processes of PET and PE containers. Referring to the properties of each plastic, explain why the processes are different. 4.Research the cost of an injection moulding tool for a common object of medium to large size: e.g. milk crate, plastic chair, garbage bin. 5.A nylon gear can be made by machining or injection moulding. Machining setup is $500 with per part / labour costs of $80/hr. Production is 10 per hour. Injection moulding tooling costs $20000 with running costs of $100/hr. Cycle time is 20 seconds. Determine the break-even quantity. EMMAT101A Engineering Materials and Processes