HS2339 Week Five Polymer Quiz Flashcards
1
Q
Structure and components of an epoxy resin. Forms a N____ Polymer, by C________. Made up of two components, which are?
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2
Q
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- Formation of C=O carbonyl groups at C-C backbone cause yellowing
Oxidation forms oxyl radical (disproportionation just means the element
involved is oxidised and reduced – gives and electron and shares an
electron. In this instance oxygen shares an electron with carbon and carbon
shares an electron with oxygen so each element provides and accepts an
electron – reduction + oxidation. - Prone to oxidation
- Free radical process through oxyl radical
- Formation of carbonyl groups
- Absorbs light -> yellowing
3
Q
Yellowing of Epoxy Resins as seen on graph
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Epoxy oxidation- forms a carbonyl group which can absorb light, hence yellowing
Bonds absorb energy at different wavelengths, peaks on graph change with addition of new bonds (conjugated double bond makes things yellow)
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5
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6
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7
Q
Structure of cellulose nitrate
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8
Q
How cellulose nitrate becomes celluloid
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9
Q
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10
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11
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12
Q
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- Oxygen, ozone, light and UV
- Cross linking, Chain scission, double bond cleavage
13
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