Performance characteristics of materials Performance characteristics of papers and boards - Performance characteristics of polymer based sheet and film — AQA A-Level Design and Technology: Product Design
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Performance characteristics of materials Performance characteristics of papers and boards - Performance characteristics of polymer based sheet and film explained
Polymer-based sheet and film are supplied in named forms you must be able to identify: foam board, fluted polypropylene (PP), translucent PP, styrofoam, low-density polyethylene (LDPE) sheet, plastazote, cellulose acetate and polylactide (PLA).
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For each, describe performance characteristics: hardness (how resistant the surface is to scratching), density (mass per unit volume, so how light a given thickness feels), food and drink safety (whether it can contact food without contaminating it), thermal conductivity (how readily heat passes through, relevant to insulation), electrical insulation (whether it blocks current) and weather resistance (how well it survives UV, rain and temperature change). For example, styrofoam is low density and a good thermal insulator, LDPE sheet is flexible and moisture resistant, and cellulose acetate is a clear, fairly hard film.
Your focus
- Name the specified polymer-based sheet and film types.
- Describe the performance characteristics of each named sheet and film.
- Match a named sheet or film to a product need using its characteristics.
Performance characteristics of materials Performance characteristics of papers and boards - Performance characteristics of polymer based sheet and film exam tips
Marking Points
- Names the required polymer-based sheet and film types: foam board, fluted PP, translucent PP, styrofoam, LDPE sheet, plastazote, cellulose acetate and polylactide.
- Describes hardness, explaining that it concerns surface resistance to scratching or indentation rather than overall strength.
- Describes density as mass per unit volume and links low density to lightweight products such as styrofoam packaging.
- Describes food and drink safety, identifying which sheet or film can safely contact food and drink.
- Describes thermal conductivity, explaining insulation value such as styrofoam or plastazote limiting heat transfer.
- Describes electrical insulation, explaining that polymers such as LDPE sheet resist the passage of current.
- Describes weather resistance, explaining how a material withstands UV, moisture and temperature change outdoors.
Examiner Tips
- 💡Learn the named list as a set and rehearse matching each material to at least one performance characteristic.
- 💡When describing a characteristic, define it briefly and then apply it, for example 'low thermal conductivity means styrofoam insulates'.
- 💡Keep the six characteristics in mind as a checklist: hardness, density, food and drink safety, thermal conductivity, electrical insulation and weather resistance.
Common Mistakes
- Substituting unlisted materials such as acrylic, HIPS or polycarbonate for the required named sheet and film: correct this by learning the specified list, including foam board, fluted PP, translucent PP, styrofoam, LDPE sheet, plastazote, cellulose acetate and polylactide.
- Confusing hardness with strength or toughness: correct this by describing hardness as surface resistance to scratching or indentation.
- Giving a property without linking it to a named material or use: correct this by pairing each characteristic with a specific sheet or film and a product context.