PKG 221 Final Exam Questions and
answers | Updated 2024/25
metals - aluminum and steel II II II II II II
II ceramics - glass, brick and concrete II II II II II II II
Natural Glass - High heat events; volcano, lightning
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Obsidian, volcanic origin. Fulgurite, lightning origin. II II II II II
Found and used by early man II II II II II
Glass beads - Probably formed accidentally
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Around 3500 BCE II II II
Early hollow glass production II II II
Egypt about 1500 BCE II II II
II Glass Packaging Production Market by Sector - 82% Beverage
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Glass characteristics - 1.An inorganic non-crystalline (amorphous) solid formed by
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cooling from its liquid state
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2.Glass does not have a melting point as temp increases but rather a range at which it is
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viscous
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Advantages of Glass - Upscale image
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Is fairly chemical inert, impermeable to gases and water vapor
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Is transparent. But we can also add color into the glass
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Can be recycled, microwaved, heated, cooled
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Acceptable for direct food contact (although it can leach out some trace amounts of II II II II II II II II II II II II II
chemicals, not affecting food)
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Rigid structure that does not change under vacuum or pressure.
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Moldable, there are a variety of shapes and designs possible II II II II II II II II II
What is the melting point of glass? - Molecular structure of liquid
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Physical characteristics of solid II II II
No distinct melting point
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Disadvantages of Glass - Heavy compared to plastic for same volume
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160 lb/ft3vs. 55 lb/ft3for plastics
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Therefore it can cost more to distribute II II II II II II
Fuel cost, handling cost, etc.
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Expensive and high energy compared to plastics II II II II II II
Fragile, susceptible to thermal shock II II II II
Not biodegradable (advantage? disadvantage?)
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Somewhat limited direct printability II II II
, Salts can dissolve out, but very small amount
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Glass Composition - Silica Sand (Silicone oxide, SiO2)
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Glass former (backbone) 68 to 73% II II II II II
Limestone (Calcium carbonate, CaCO3) II II II
Increases chemical durability 10 to 13% II II II II II II
Soda ash (Sodium carbonate, Na2CO3) II II II II
Promotes melting 12 to 15% II II II II
Fining agents - Makes CO2 gas, combines with other to make bigger bubbles
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Carbon, Saltcake II
Decolorizes - Flint (clear) has some iron in it naturally
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Iron makes it slightly green
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Add selenium to make it slightly pink
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Pink and green makes gray, appears clear
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II Colorizers - most are metal oxides II II II II II II II
Amber Glass - Iron + Sulfur + Excess Carbon
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Made by the "reduced" process (less oxygen available)
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Absorbs <450nm wavelength II II
Light protection - beer, pharma, other
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Cullet - recycled glass - 2 types: Plant Cullet (internal) - defects, testing. Ecology Cullet -
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post consumer. II
Furnace usage is 15-90%. Average is 34%. II II II II II II
10 states have bottle deposit bills, including Michigan
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Cullet size is approximately 3/8" pieces II II II II II
Much less energy to melt, process at 2400F vs 2800F
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Every 10% = 2-3% energy cost reduction II II II II II II
Every 6 tons used = 1 ton reduction of CO2footprint
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1 recycled bottle = computer power for 30 minutes.
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30 day cycle, bottle to bottle
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II Pharmaceutical Glass - Type 1, Type 2, Type 3 II II II II II II II II II II
Type 1 - this glass is a borosilicate glass and has the most stringent extractable
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standards. A disadvantage is the higher melting point of this glass type
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70% silica II
10% boron oxide II II
8% sodium oxide II II
8% potassium oxide
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1% calcium oxideII II
Used for pharma packaging, lab ware, telescopes, guitar slides, etc
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