Polymers (Materials option)
Gbogbo ọrọ náà
Polymers are the materials that quietly shape modern life: the casing of your phone, the bottle your water comes in, the insulation around every cable in your home. The word itself tells the story - a polymer is built from many (poly) repeating units (mers) joined into long molecular chains. How those chains are arranged, and whether they can be re-melted or are locked permanently, decides everything about how a polymer behaves and how a designer can work with it.
This note covers the 0445 Materials-option polymer objectives in depth: how polymers are classified, the stock forms they are bought in, their key properties and environmental impact, the named thermoplastics from nylon and HDPE through to PLA, the two thermosetting resins you must know, and the growing family of biopolymers. Concrete product examples run throughout so you can justify a material choice, not just name one.
Ebumnobi
- demonstrate knowledge of polymers, including biopolymers, and understand their classification, stock forms, properties, environmental impact and uses
- demonstrate knowledge of thermo polymers, for example: - nylon - low- and high-density polyethylene (LDPE and HDPE) - polyethylene terephthalate (PET) - polyvinyl chloride (PVC) - acrylic (PMMA) - polystyrene (PS) - polypropylene (PP) - acrylonitrile-butadiene-styrene (ABS) - polylactic acid (PLA)
- demonstrate working knowledge of the following thermosetting polymers: - polyester resin - epoxy resin.
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Nnyocha Ọmụmụ
Ekele diri gi maka imecha ihe karịrị na Polymers (Materials option). Ugbu a na ị na-enyochakwa isi echiche na echiche ndị dị mkpa, ọ bụ oge iji nwalee ihe ị ma. Ngwa a na-enye ụdị ajụjụ ọmụmụ dị iche iche emebere iji kwado nghọta gị wee nyere gị aka ịmata otú ị ghọtara ihe ndị a kụziri.
Ị ga-ahụ ngwakọta nke ụdị ajụjụ dị iche iche, gụnyere ajụjụ chọrọ ịhọrọ otu n’ime ọtụtụ azịza, ajụjụ chọrọ mkpirisi azịza, na ajụjụ ede ede. A na-arụpụta ajụjụ ọ bụla nke ọma iji nwalee akụkụ dị iche iche nke ihe ọmụma gị na nkà nke ịtụgharị uche.
Jiri akụkụ a nke nyocha ka ohere iji kụziere ihe ị matara banyere isiokwu ahụ ma chọpụta ebe ọ bụla ị nwere ike ịchọ ọmụmụ ihe ọzọ. Ekwela ka nsogbu ọ bụla ị na-eche ihu mee ka ị daa mba; kama, lee ha anya dị ka ohere maka ịzụlite onwe gị na imeziwanye.
- Which statement about thermosetting polymers is correct? A. They soften every time they are heated B. They can be re-melted and recycled repeatedly C. They cure permanently and cannot be reshaped by heating D. They are always made from renewable plant sources Answer: C
- Which polymer is best suited to a transparent, weather-resistant sign that must be polished to a clear finish? A. Acrylic (PMMA) B. Low-density polyethylene (LDPE) C. Nylon D. Polypropylene (PP) Answer: A
- LDPE is softer and more flexible than HDPE mainly because: A. LDPE is a thermoset and HDPE is a thermoplastic B. LDPE chains are branched and pack less tightly than HDPE chains C. LDPE contains a plasticiser and HDPE does not D. HDPE is made from plants and LDPE from oil Answer: B
- Which property makes nylon a good choice for small gears and bearings? A. It is optically transparent B. It is biodegradable C. It is tough, hard-wearing and self-lubricating with low friction D. It melts at a very low temperature Answer: C
- Which statement about PLA is correct? A. It is an oil-based thermoset B. It is bio-based and biodegradable but composts best in industrial conditions C. It cannot be used in 3D printing D. It is the toughest polymer in the syllabus Answer: B
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Rue ajuju ndi a n'ime ngwa ahu
Akwụkwọ A Na-atụ Aro
Meecha Ajụjụ Ule Ọmarịcha
Ị chọrọ ime ajụjụ ule ọmarịcha gbasara Polymers (Materials option)? Budata ngwa Green Bridge CBT iji nweta ajụjụ ule ọmarịcha na nyocha zuru ezu gbasara isiokwu a.
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Ihe nile ichoro iji nwee ihe ịga nke ọma na JAMB, WAEC & NECO.
