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Would you describe glass as a natural material? Synthetic Material? Renewable? Biobased? Petroleum-based Material?
natural
How would you describe metals using the descriptors above?
natural material? Synthetic Material? Renewable? Biobased? Petroleum-based Material?
natural
What are two challenging aspects of glass with regards to sustainability? (Think weight and energy)
glass is more dense and requires more 15-30x more material
requires high amounts of energy and energy prices
What main advantage does glass have with respect to plastic or paper? (Think barrier properties)
it has high barrier properties, can create air tight seals
there is no additional need for a liner, no leaching of glass substrate
How does glass rank among the most recycled materials?
higher than plastic but lower than paper
If the height and width of a bottle is 10 x 3 x 3 cm (its cube dimensions) and the actual bottle is 40 cm3, what is its cube efficiency?
V= 40 cm³
10×3×3= 90 cm³
40/90 × 100= 44.4%
What is the biggest emissions component of glass manufacturing?
CO2?
What is the Environmental Kuznits Curve?
describes how environmental degradation typically reaches a peak before new innovations take over to decreased impacts
When GDP increases for a country what happens to the sustainability of products?
It increases, as more income allows for redesign for sustainability
What are two reasons for the decline of reusable glass bottles?
Cheap plastic and aluminum, cost of transport, recycling of plastic and aluminum etc.
What is the #1 priority for the EPA with regard to pollution prevention?
source reduction
What are two pollution prevention practices?
reduce
reuse
What is cullet?
Recovered glass to be recycled
What recycling rate did the Glass Products Institute find that offset the shipping emissions of recycled glass?
50% recycling rate
In the LCA of different collections systems by Simon et al., they found that deposit and return systems had the highest impacts. Why was this so? Is their assumption about personal transport to the supermarket valid?
they included the emissions of transportation to the grocery store
this is debatable because you’re usually grocery shopping when you go to the store, therefore you were going anyway and it’s not an additional trip
Why did larger glass containers have lower impacts than smaller containers?
?? GHGs remarkably increase when container size goes down due to higher specific weight of the container
Do you agree with the recycling credit given in their study? Justify your answer
How does a “sea of electrons” make metals recyclable?
The sea of electrons is what occurs when several metal atoms bond with each other.
Overlapping atomic orbitals allow the electrons of each atom to move freely among all the different bonded atoms
this allows the metals to be re-worked and recycled bc the bonds don’t break
What is unique about aluminum recycling in terms of its value?
it has a higher material value than glass or plastic at $991/ton as a waster material
covers collection and processing costs
Which packaging material has the highest closed loop recycling rate: Aluminum, glass, or PET?
aluminum (~93%)
Calculate the recycling rate given the following data: Domestic recycling 1.0 billion lbs, exported recycled 45 million lbs, imported recycled 30 million lbs. Virgin Domestic production 2.5 billion, exported production 45 million, imported production 50 million.
recycled + exported - imported
production + imported - exported
Are aluminum cans competitive with PET and Glass with regards to GHG emissions?
yes, emission not as great as glass and PET b/c aluminum is so light
Why does flexed aluminum film have similar barrier properties to flexed metalized PET but much higher barrier properties when un-flexed?
similar properties due to pinholes in flexed material
better properties when unflexed bc there are no pinholes present
What property does steel have a 2-3 times higher value of?
Density is higher than Al
Why are coatings used on steel?
to prevent rusting
What is one drawback of using polyester over BPA coatings in food containers? What is one advantage?
drawback: susceptible to acid attack in foods
advantage: can be mixed/blended to become inert and lower migration
What is the difference in a basic oxygen furnace and an electric arc furnace? What is the advantage of an electric arc furnace?
BOF: oxygen reacts with carbon to produce steel from iron
EAF: electrodes melt down scrap with electricity
advantage of EAF: can make steel from 100% scrap whereas BOF is only 25%
In a fiber reinforced composite, how do the added fibers strengthen the material?
by transferring loads put on the polymer
What are two advantages of fiber reinforced composites?
Higher Strength to weight ratio
lower corrosivity
Why is carbon fiber so strong? I.e. what is graphite?
CF is produced from PAN or pitch, through wet spinning, and sequential heating above 2000o C to create graphitic carbon
graphitic C responsible for strength
graphite is highly crystalline carbon
What is an advantage and disadvantage of natural fibers in composites?
adv: less expensive
disadv: can have high water adsorption
Why is the interfacial region so important for composites?
without interfacial adhesion you can get microcracks that weaken the composite
Why are carbon fibers and aramid fibers often etched?
improves off-axis strength
To improve adhesion of the fiber to the matrix
Describe the sustainability challenges of multilayer packaging. What is one way of recycling these materials?
difficult to recycle the packaging bc the avg consumer can’t separate the layers and there is no single stream for multilayer packaging
turning the MLP into something else such as gravel for landscaping or material similar to concrete blocks
Note 
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