Chemical Engineering of Polymer

Dr. Jim Silva

Chemical Engineer at GE

Drying Aqueous Salts for Polyetherimide Monomer Synthesis

Basically what Dr. Silva was trying to do was create a thermoplastic  that could retain its structural integrity  up to temperatures of 180 degrees Celsius. He wanted this plastic to be light weight, as well as electro-platable which means it  a very thin surface of metal can be electro-chemically put onto it, giving it  shiny finish without  no corrosion. To make the polymer, he wanted to make a bisphenol into an organic salt. The product needed to be created in water, but because the rest of the process required water-free organic salt, the water had to be removed. It was, however,  fine to have the product floating in a non-aqueous solvent.

When they did the process for one bisphenol, it was well-behaved and resulted in fine crystals. The product was full of water to start with, but they needed  it to be dry. A boiling solvent wasadded and then a chemical was sprayed into the solvent. This caused evaporation and left behind the salt in the remaining solvent.

When this process was repeated with a biphenol, it resulted in big particles and caking on the walls. It was discovered that the new polymer was taking much longer to dry; therefore they needed to make the new polymer at a much higher temperature. With this approach, an extremely large amount of solvent would boil off with the water.

In order to fix this they changed from a short path condenser to a partial reflux condenser that allowed much of the condensate to return to the original mixture. The idea was to condense at a temperature that was warm enough to keep the water if vapor phase but cool enough to condense the solvent and return it to the mixture. But this process is never perfect so some water inevitably gets condensed and returned to the initial mixture.  Because of this, they believed that the partial reflux condenser would not work. They thought with the partial reflux condenser too much water would be left behind in the mixture, but then they did an experiment to see that wasn’t true. They recalled the Gibbs Phase Rule which gave the theoretical reason for what they observed- that by fixing temperature and pressure, the composition in the condenser would necessarily not change. As a result they reduced the wasted solvent by an enormous amount, making the process phenomenally more cost effective.

Terms

• ·         Thermoplastic- a material (usually resin based) that is rigid when cooled, but deformable when heated. The material can repeatedly be heated and cooled.
• ·         Cellulose –Repeating glucose units. Arguably the most common polymer on earth.  Cannot be digested by humans. Starch (easily digestible by humans) is also a  glucose polymer. However cellulose and starch link the repeating units in different ways, making a huge difference!
• ·         Bisphenol- a class of organic chemicals (organic meaning made from carbon, not meaning free of pesticide!) that is characterized by having two hydroxyl-phenyl groups.  Saying something is a “bisphenol” is to categorize it chemically like saying something is a carbohydrate or an alcohol or an ester.
• ·         Biphenol – A subtly different substance from the one referred to as a  bisphenol. Our guest used this to distinguish between two similar substances whose specific names he did not want to disclose.
• ·         Short path condenser – a condenser cools a vapor back into a fluid. A short path condenser removes that fluid from the original mixture. In our example, any solvent that is boiled off with the water gets removed from the process and then needs to be dealt with as recyclable or non-recyclable waste
• ·         Gibbs phase rule - essentially that degrees of freedom or things you can adjust in a process = number of phases minus number of components, plus two. So if T and P are fixed, the relative proportions of the mixture are defined, cannot change.
• ·         Partial reflux condenser –a condenser cools a vapor back into a fluid.  A partial reflux condenser allows some of that condensate back into the initial mixture to be reboiled. Because the solvent and water have different boiling points, the two  can be mostly separated using this process.
• ·         Ppm- parts per million. A term used to describe concentration, similar to percentage (parts per hundred)
• ·         Electroplating- coating something with a thin layer of metal through the use of electricity
• ·         Scale and scaling of a process- the larger the scale of the project, the more money and time it takes. More importantly, scaling a process is not as straightforward as it sounds. In this example doing something in the lab at the gram scale was simple, but doing it at the scale of metric tons posed many complications – large amounts of waste solvent, challenges to mixing and heating, etc. A classic example of scaling comes with the ratio of surface area to volume. Surface area increases at a squared rate, while volume increases at a cubed rate. In the case of mixing or heating, this has major implications.  Imagine how long it takes to heat a 3 x 3 x 3 cube has a surface area of 54 square units and a volume of 27 cubic units. A 30 x 30 x 30 cube has a surface area of 5400 square units but a volume of 27,000 cubic units. You can easily see that heat transfer, fluid dynamics, and many other process variables will be affected by this dramatic shift in ratios.

Connections

·         Dr. Linhardt- The chemical engineering process and scaling

·         Dr. Ullal and Dr. Palermo-  Discussion of polymers

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Polymer process outline

·         Dr. Jim Silva, Chemical Engineer at GE

·        

·         He talked us through a real life problem and how he solved it:

o   Trying to produce a low-weight, electro-platable thermoplastic that could hold up to temperatures of 180 C.

§  Wanted to make a bisphenol into an organic salt that could then go on and be used to make the polymer

§  Creating the product required water but rest of process needed water-free organic salt

§  But it was OK to have desired product floating in a non-aqueous solvent

o   Scaled up a lab process for one particular bisphenol and it worked fine

§  Needed a dry product but it was full of water

§  So add a large amount of boiling solvent

§  Sprayed wet chemical into boiling solvent

§  Water and vapor would evaporate, leaving desired salt behind in remailing solvent.

§  Some of solvent would boil off too, but this was condensed by short path condenser and then treated (not reused in process.) The loss of solvent was OK as it wasn’t so much that the process became cost prohibitive.

o    But when they tried to repeat the process for a different biphenol (not bisphenol) they got big chunks of salt caked to the walls, not fine particles suspended in solvent.

o   Analyzed situation and discovered newer polymer was taking much longer to dry at a given temperature so needed to make the new polymer at a much higher temperature, but this meant way more solvent would boil off with the water. Way more!

o   Came up with a solution (details not listed in this outline)

·         Terms

o   Thermoplastic

o   Cellulose

o   Bisphenol

o   Biphenol

o   R group (as in HO-R-OH)

o   Short path condenser

o   Thermos gravitational analyzer

o   Materials balance

o   Gibbs phase rule – essentially that degrees of freedom or things you can adjust in a process = number of phases minus number of components, plus two. So if T and P are fixed, the relative proportions of the mixture are defined, cannot change.

o   Partial reflux condenser

o   ppm

o   electroplating

o   Scale and scaling of a process

o   Chemistry versus chemical engineering

o  

·         Connections to other guests

o   Linhardt (scaling, process simplification, cost effectiveness etc.) Others:

Bio-diesel

David Connor and Brian Murray and Ray,

Bio-diesel (Chemical Engineering Dept.)    11/20

Terms:

·         Biodiesel-A fuel source produced from vegetable oil, fats, or grease

·         BTU’s-British Thermal Unit equivalent to 1055 joules; amount of energy to raise 1 lb of water 1 degree F

·         Ethanol-Ethyl alcohol, a two carbon alcohol found in fuels and found in liquor. Typically liquor has a maximum of 40% ethanol (diluted with water). The ethanol is very purified through distillation.  Ethanol used for fuel is essentially just ethanol, but not in a very pure form, so it tastes worse than food-grade alcohol (if that’s possible!)  Ethanol is typically mixed into fuel at a 10% content to oxygenate the gasoline so that it can burn more cleanly and meet the Clean Air Act amendments of the early 90’s. Until the mid 90’s MTBE was typically chosen for this purpose but in the late 90’s MTBE was found to be leaking into drinking water. This added a terrible taste to the water. It is unclear if MTBE is carcinogenic.

Social value-Some emissions created by biofuels are  considerably less than that of traditional diesel , reducing pollution produced by vehicles. http://www.crimsonrenewable.com/emissions.php  Specifically, net carbon emissions are less because the carbon in biodiesel comes from plants, a renewable source. (For a gram of carbon  to be released by combustion that same gram of carbon had to be  taken out of the atmosphere by photosynthesis for a net carbon emission of zero.)  This could be a useful alternative for fossil fuels in the case of a shortage or to just reduce green house gas emissions IF the biodiesel is made from used cooking oil. If the biodiesel is made from UNUSED cooking oil, its benefit is likely reversed by the deforestation it causes. (cutting down trees to grow oil-producing crops.)

Government and economics

Biodiesel could potentially reduce the reliance of the US on foreign oil, relieving some political tension.  It may also possibly reduce the cost of fuel, as fatty food wastes are abundant in America. There are about 3 billion gallons of waste fuel oil generated by the US each year.  Americans use 100 billion gallons of gas in the same period. So we would have to grow oil crops. The big issue there is  that there is some risk involved with both our major fuel and food sources being the same.  If there is a shortage then both are in trouble. Also, this would set up a trade off in resources between fuel and food ; some fraction of the water and farmland that could go to produce food would go to produce fuel instead.

Concepts continued:

·         Carbon REcycling International is a company that uses CO2 and water to make methanol products, mostly fuel for flexibly fueled (FF) cars.  One possible issue with FFcars, that I found, is that methanol is slightly corrosive, leading to increased wear on certain parts.  This process also solves the food/fuel source issue, as it is not produced from feedstock, but from CO2 and water.

Connections

o    Borton and Cleanroom and Dehnert (renewable energy,solar)

o    Dr. Silva and Dr. Linhardt (Scaling up production of a product)

Improving Lithium-ion Batteries

Improving Lithium-ion Batteries

Dr. Nikhil Koratkar

Battery Research in the Koratkar Lab at RPI

Materials Science and Nanotech

November 20, 2015

Battery technology is becoming increasingly important to our society. Instead of using batteries to only power simple electronics, we are attempting to engineer better batteries that can power cars, houses, and advanced technology such as cell phones and computers. Since 2012, research in the Koratkar Lab has led to discoveries that improve lithium-ion batteries.

While trying to improve batteries one must consider the charge rate, power/energy density, and weight of the battery. By improving the charge rate, the battery can reach full charge faster. By increasing the energy density. the battery can last longer by storing more energy. In order to be used in portable technology such as phones, the battery must be light weight. By improving these areas a better battery can be made. Although, making improvements means finding a balance between all of the different factors.

At RPI, Dr. Koratkar focused on improving the electrode material within lithium-ion batteries. Since the cathode is made of lithium cobalt oxide and it works very well, he focused mainly on improving the anode which consists of sheets of graphene (layers of graphite that are just one atom thick). When the battery is discharged, lithium ions from the cathode migrate to the graphene. When the batter is recharged, the lithium ions return to the cathode.   Inherently, the graphene sheets can only accept a limited amount of lithium ions. So to improve the battery, one can add more graphene, or find a way to get the graphene to accept more Lithium ions. Dr. Kortakardeveloped a process that creates an open pore structure within the sheets of graphene. This creates more space to store the lithium ions and more surface area for the ions to diffuse into the graphene.

Process

Step 1: allow the graphite to undergo oxidation for 96 hours

Step 2: Ultrasonicate the graphene oxide in water to get graphene oxide paper

Step 3: Remove the oxygen and some carbon (CO₂) by using a thermal shock (quickly heat to 700 degrees Celsius for 45 seconds); this thermal shock can also be delivered by photons (similar to a camera flash)

As the thermal shock removes CO₂ it creates vacancies or defects in the carbon structure of the graphene (the C in the CO₂ comes from the graphene).  The thermal shock also disrupts the graphene structure making it porous. After testing this new material in the lab it was discovered that the capacity greatly increased. The original capacity of the graphite sheets was 370 mAh/g while the capacity of the new porous graphene sheets was 900 mAh/g. This means the new material can hold many more lithium ions in the anode. The reason for this is in the traditional material (graphite sheets) when the positive lithium ions combined with electrons in the anode they did not want to stick to the graphite sheets so they just hovered between them. Since the new material has vacancies, when the lithium ions diffuse into the new material they stick in the spots where the vacancies are. In comparison, the traditional material was LiC₆ while the new material is Li₃C₈. This research in the lab showed that the more defective the anode material (up to a certain point) is the higher the capacity/ energy density.

In addition to improving the energy density, Dr. Koratkar  improved the charge rate. Charging a battery is limited by how fast the lithium ions diffuse into the anode. In the porous material the ions can diffuse everywhere instead of just on the edge like the original graphite sheets. This means the battery can be charged for less time because the ions diffuse faster. This was proven when the charge time was decreased to 24 seconds and the power density increased. Ideally, thisporous anode could eventually be optimized to the point that it could be  used to start a car. Since a lot of power is needed to start a car, in order to use a battery it must have a very high power density in a short amount of time. However, in order to apply this to a realistic situation the volume of the battery had to be normalized. So, in the lab the defected graphene was compressed to a realistic size for an anode. The compression closed some cracks and pores so when a charge was applied the power density was not as great but the energy density was still high. This shows that while designing a new idea some desired results may be compromised. In this case, normalizing volume is not good for graphene when a high power density is desired.

Concepts/ Vocabulary

Energy density- The amount of energy stored in a given system or region of space per unit volume or mass

Power density- the amount of power per unit volume

Power=energy/time

Economies of scale- a proportionate savings in cost gained by an increased level of production

Example: The cost of implementing the process to make graphene porous is justified by the increase in production of these new lithium-ion batteries.  (In this case we would want to produce morebecause they have more advantages then traditional lithium-ion batteries)

Oxidation- combining with oxygen; electrons are lost

Ultrasonicate in water- breaks open the graphene oxide into layers with an ultrasound and water

-Phones need a battery to last 1,000 charge cycles while cars need a battery that can last 10,000 charge cycles

-Patent ideas first then publish

-Ideas are useful but in order to be used in production for manufacturing they must be able to be scaled up

-for the production of drones the battery that powers them must be light weight

Government:

Funding for researching lithium-ion technology comes from grants (National Science Foundation, and NY State energy research development authority)

Connections

SME project/Mr. Chiappone: Scaling up; high rate manufacturing at low costs

Materials Science and Engineering/ Professors Ed Palermo and Chaitanya Ullal: The concept of vacancies in materials; Structure defines function

Dr. Linhardt: scaling up ideas that work on the small scale; using grants to fund research; patenting ideas in order to publish them

Mr. Silva: Improving a traditional version of an idea to make it work better; scaling up ideas for large scale production

Ms. Moldoff: utilizing grants/funding from the government 

Heparin

November 10, 2015

Presenter: Dr. Linhardt

Department: Chemistry & Chemical Biology

Topic: Bioengineering and Metabolic Engineering of Heparin Drugs

Modern medicine would cease to exist without heparin.  Heparin is an anticoagulant (prevents clotting), extensively used during surgery, transplants, and dialysis.  The market for pharmaceutical heparin is approximately worth $7 billion (1 Bill Gates).  It is obtained from pig intestines and the product is unregulated during its early stages, which has led to contamination of the drug (lives lost).  Additionally, a majority of the production is controlled by China (hard to enforce regulations and could mean instability in supply).  There is an essential need for an “alternative and more controlled source of heparin” because it would be nearly impossible to perform complex medical procedures that save lives without heparin.  

Linhardt and his students are using biomolecular engineering and metabolic engineering to attempt to manufacture an alternative source of heparin.  Heparin production would then be reliant on microorganisms which would produce the product by complex a complex metabolic process including the production of enzymes (biomolecular engineering). Heparin is a carbohydrate and therefore not made by ‘simply’ hijacking bacterial DNA in the manner that is used to produce proteins.  The metabolic engineering project is attempting to manufacture heparin through fermentation in bacteria.  The issue is that bacteria are not compartmentalized, and lack a Golgi body, thus making it difficult to organize the processes.  Additionally, a problem with making an alternative source is scalability (increase production in 11 orders of magnitude) and intellectual property (patents).  Once research approaches a certain stage it has to be performed at companies and not universities, because universities require publication and intellectual property protection requires secrecy.

Linhardt’s research for an alternative source of heparin is essential to medicine.  Medicine affects many political and economical decisions.  Heparin could lead to war if the supply became inadequate since it is currently an unstable supply chain.  It can be only be produced at the large scale by pigs and the industry is controlled by China.  Currently, foreign diplomacy is necessary to ensure the product’s supply.  Conflicts with China could lead to a scarcity of the product.  Also, an inefficient process is used to produce Heparin (one pig only gives 2 doses) and diseases (if many pigs were suddenly affected by a disease)) could endanger the product.  Corruption and military takeover (rationing) could result if the quantity of the product becomes insufficient.  The U.S. currently maintains strategic reserves of the product in case of contamination.  The distribution of the drug would have to be prioritized in case of an emergency.  It is also a $7 billion industry so foreign companies are always looking for ways to improve their profit.  Adulteration has previously occurred, risking the purity and safety of the drug (effectiveness).  If a new source for heparin was found, developing nations could also benefit from the drug and modern medicine practices since it may be available in larger quantities.  Additionally, the U.S. would not have to rely on other countries.

Connections: 

·         Ms Moldoff- Government regulations apply in chemical and civil engineering.

·         Clean room/ PN Junctions- It is difficult to manufacture bacteria that produce heparin, because bacteria are at the nanoscale and are alive.  PN Junctions were difficult to produce because they had to be manufactured at the nanoscale.

·         MILL- The goal is to make the U.S. self sufficient, and develop an effective and efficient manufacturing process (preferable assembly line process). It involves research and grant proposals to fund the cost ($2 million/ year).  We are looking to manufacture in large quantities (economies of scale) to make it cheaper.

·         Dr. Silva – chemical engineering process, and scalability issues/complexities

Terms Defined:

·         Dialysis- It is used to purify blood (filter toxins) if kidney is not working properly.

·         Adulteration- To make impure by adding foreign or inferior substance.

·         Natural Product- It is a substance (chemical/ biological elements) derived or obtained from nature. Not all natural substances are good, e.g. radioactive Uranium isotopes and cyanide are both ‘natural’

·         Synthetic Product- It is an artificial compound made through chemical reactions.

Sources

http://www-heparin.rpi.edu/main/files/projects/51c7432f219789.47819866.pdf

High Speed Video

Mr. Dehnert

Nov 4^th 2015

Couriertronics  (Electrical Engineer)

High Speed Video

Social Values:

-          The use of high tech slow motion cameras can apply to many fields of study. Slowing down high speed actions and reactions can help scientists and engineers observe, analyze, and gather data from things like explosions to car crashes. Being able to understand things like car crashes and what happens during such a collision enables engineers to innovate and implement safer vehicle technology to protect everyday lives. Here (just for fun) is a link to a system that can visualize near the speed of light! http://news.mit.edu/2011/trillion-fps-camera-1213

Government and Economics:

-          The use of nanotechnology is heavily linked to the camera industry and slow motion capturing technology. Silicon is one of the main elements used for camera technology to manufacture circuits and image detectors that enables cameras to function. Silicon is also used because it is a very abundant element. The use of this nanotechnology contributes to how expensive some cameras are. Being able to manufacture and produce this technology at large quantities and implementing them into cameras helps find a balance in pricing. That is where economies of scale comes into play.

Terms:

-          Image Detector – made of silicon (1000 x 1000 pixels in slow-mo detector)

-          Pixel – Stands for picture element
-      Voxel - 

-          Blur – Motion across a pixel causes blur

-          Hysteresis – phenomenon of our eyes that remembers a past image while another one is being seen, causing images to look continuous

-          Frame rate – the frequency at which a picture sequence is displayed

o   Frame rate of the human eye – 24-30 frames/second

-          Human blink -  200 milliseconds

-          Photoelectric  effect – electrons that are emitted when light shines upon them (discovered by Albert Einstein)

Concepts:

-          Different materials sensitive to different wavelengths

-          Silicon is sensitive to the same wavelengths our eyes see

-          Difference in charges (of e^-) across a pixel field is relayed by a circuit which is then displayed as an image

-          To get a color image, filters are put over pixels so only desired wavelengths can penetrate

-          Different materials are sensitive to different wavelengths

-          Depth of view gets narrower when capturing high speed images

-          $30,000-$120,000 for high speed capturing cameras

Connections:

SME – high speed cameras can be used to diagnose manufacturing problems

PV cells – also use silicon because Si inherently interacts with light from a very similar wavelength distribution to that of the sun’s light

And a little summary from last year’s student:  Normal cameras capture images at 30 to 60 frames per second (fps).  This is close to the rate at which humans perceive images, making these frame rates appropriate for recording at normal speeds.  Frames are captured when pixels behind the lens of the camera are exposed to light.  These pixels are extremely small, and sensitive to visible light.  Silicon is a good material for this purpose because it absorbs light at visible wavelengths (400 to 700 nanometers).   Photons reflected off of the objects or people being recorded hit the pixels, and the absorbed light is recorded for each pixel.  The image quality depends on the number of pixels and the amount of light that hits the pixels.  High speed cameras, with frame rates of up to millions of fps, are specially designed to move this high quantity of information very quickly.  One way they record so quickly is by moving the information from the pixels that are exposed to layers of pixels underneath that store the information until it can be transferred to a computer.  Recording at high speeds requires more light, so sources of light are often set up to ensure good exposure on the pixels. Mr. Dehnert gave us an analogy of rain and buckets with lids. To take many frames per second, the “lid on each bucket” (pixel) is opened for such a short amount of time that very few “raindrops” (photons) have time to get in, so we need a lot of light.

An Insight to Light Rail

Name of Presenter: Ms. Moldoff

Department: Civil Engineer

Date: October 30, 2015

Social Value:

Civil engineering is the primary drive behind the vast networks of infrastructure across the globe. It is this system of roads, canals, bridges, and the like that allow us to ship a package across the country or drive safely on an interstate. Civil engineering will continue to be the backbone that allows for the success of our global society. Here in our backyard, the promotion of the rail industry will allow for more efficient methods of transportation in the Capital Region,by reducing the amount of congestion on the roads and railroad stations. The development of highways over railways and roads had significant cultural impact and social implications that can be read about here: http://www.uvm.edu/landscape/learn/impact_of_interstate_system.html (No, that's not going to be on the quiz.)

Government/Economics:

There is interesting history about the role of government in promoting interstates over highways. Some can be found here: http://www.history.com/topics/interstate-highway-system .(No, that's not going to be on the quiz.) Here in our backyard, the government funding of the rail industry will allow for more efficient methods of transportation in the Capital Region. This project, which was started in 2008 and is currently in construction, has received ~$680M worth of grants from the state and federal governments. The plan included an additional 17 miles of track on the Albany Schenectady double line as well as the expansion at the Rensselaer Station, among the busiest in the nation. One goal of this project is to reduce the travel time for commuters, but the newly added tracks could also be used for freight trains. Moving goods by train is more efficient than by tractor-trailers on the interstates because greater amounts of material can be shipped by train making for greater fuel efficiency. Also,  large trucks cause greater wear and tear on the roads which costs additional money to replace.

Concepts/terms:

·         Berms: In this case, piles of debris moved during construction that has been covered by a soil fabric. Berms can also mean any natural or artificial embankment or any strip alongside a road.

·         Control Point: A location that controls the positioning of the tracks.

·         Positive Train Control (PTC): Automated system to control the speeds of trains.

·         Trains cannot tolerate a 2% grade.

·         Trains can be as fast as 124 mph and still have at grade intersections. They take several miles to stop and can’t be easily heard from a distance

·         Tracks are laid down at 95 degrees F  to prevent warping

·         Ballast – material (usually crushed rock) that creates friction to stop metal train tracks from moving. (In other context, balance is a heavy weight used for stability)

·         Superbalance – raising up one side in a curve to keep train from tipping or going off track (banking in a turn)

·         Culvert – a tunnel that goes underneath a road or track

Connections:

·         Possibly Dr. Borton with the reduction of fossil fuels being spent on tractor-trailers shipping goods.