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Questions and Answers
Which of the following best describes a plastic?
Which of the following best describes a plastic?
- A simple element found on the periodic table.
- A material composed of large molecules that are synthetically made or modified. (correct)
- A naturally occurring mineral compound.
- A material composed of small, naturally occurring molecules.
What happens to thermosetting plastics when heated?
What happens to thermosetting plastics when heated?
- They turn to ash and cannot be used to make new objects. (correct)
- They become more flexible and elastic.
- They melt and can be reformed.
- They soften and can be reshaped.
Which of the following is a characteristic of thermoplastics?
Which of the following is a characteristic of thermoplastics?
- They are only suitable for single-use applications.
- They decompose upon heating.
- They soften when heated and can be reshaped. (correct)
- They maintain a rigid shape regardless of temperature.
In what year was Polyethylene first created?
In what year was Polyethylene first created?
Which of the following is an application of Fluorocarbon?
Which of the following is an application of Fluorocarbon?
Which polymer is used in living hinges and safety helmets?
Which polymer is used in living hinges and safety helmets?
Acrylonitrile-Butadiene-Styrene (ABS) was first made in 1948, what is it commonly used in?
Acrylonitrile-Butadiene-Styrene (ABS) was first made in 1948, what is it commonly used in?
What makes plastics useful in the automotive industry?
What makes plastics useful in the automotive industry?
Which of the following is a common application of blow molding?
Which of the following is a common application of blow molding?
Which molding process is most suitable for creating complex, three-dimensional parts such as plastic model kits and bottle caps?
Which molding process is most suitable for creating complex, three-dimensional parts such as plastic model kits and bottle caps?
Which of the following processes involves forcing a melted plastic through a die or nozzle?
Which of the following processes involves forcing a melted plastic through a die or nozzle?
Which of the following products is commonly made using extrusion?
Which of the following products is commonly made using extrusion?
What adaptation has influenced blow molding technology?
What adaptation has influenced blow molding technology?
Which polymer is primarily utilized in gears?
Which polymer is primarily utilized in gears?
Which processes involves injecting molten polymer material between two closed halves of a mold?
Which processes involves injecting molten polymer material between two closed halves of a mold?
What is the approximate value of plastic materials used in the medical field in the United States as of 2000?
What is the approximate value of plastic materials used in the medical field in the United States as of 2000?
Which characteristics of Polycarbonate make it suitable for eye protection?
Which characteristics of Polycarbonate make it suitable for eye protection?
What is the primary purpose of the 'screw' component in the extrusion process?
What is the primary purpose of the 'screw' component in the extrusion process?
In the melt spinning process, what is the role of the cooling air?
In the melt spinning process, what is the role of the cooling air?
Which of the following properties makes silicone suitable for use in gaskets, tubing, and utensils?
Which of the following properties makes silicone suitable for use in gaskets, tubing, and utensils?
Which of the following factors primarily contributes to the increased use of plastics in the aviation industry?
Which of the following factors primarily contributes to the increased use of plastics in the aviation industry?
Which of the following materials are injection molded?
Which of the following materials are injection molded?
Which polymer is a key component of milk jugs?
Which polymer is a key component of milk jugs?
What aspect of plastic usage is most applicable to medicine?
What aspect of plastic usage is most applicable to medicine?
What properties make polymers suitable for foam cushions?
What properties make polymers suitable for foam cushions?
How does increasing the use of plastics in automobiles affect fuel efficiency?
How does increasing the use of plastics in automobiles affect fuel efficiency?
Which of the following statements accurately describes the relationship between the cooling cycle and the mold in injection molding?
Which of the following statements accurately describes the relationship between the cooling cycle and the mold in injection molding?
What is the role of the 'spinneret' in the melt spinning process?
What is the role of the 'spinneret' in the melt spinning process?
Why is understanding the thermal properties of different types of plastics, such as their glass transition temperature (Tg), crucial in selecting a manufacturing process?
Why is understanding the thermal properties of different types of plastics, such as their glass transition temperature (Tg), crucial in selecting a manufacturing process?
In the context of polymer classification, what distinguishes elastomers from thermoplastics and thermosets?
In the context of polymer classification, what distinguishes elastomers from thermoplastics and thermosets?
During which stage of injection molding would issues such as 'short shots' (incomplete filling of the mold cavity) most likely be detected?
During which stage of injection molding would issues such as 'short shots' (incomplete filling of the mold cavity) most likely be detected?
Which material is used in skin packages and golf balls?
Which material is used in skin packages and golf balls?
You are tasked with selecting a plastic for a component that must withstand high temperatures and maintain its structural integrity. Which material would be the most suitable?
You are tasked with selecting a plastic for a component that must withstand high temperatures and maintain its structural integrity. Which material would be the most suitable?
A design engineer is creating a new type of medical implant that requires a material that is both biocompatible and can be precisely shaped. Which manufacturing process would be MOST appropriate?
A design engineer is creating a new type of medical implant that requires a material that is both biocompatible and can be precisely shaped. Which manufacturing process would be MOST appropriate?
A company is looking to reduce the environmental impact of its packaging by using a material that can be repeatedly softened and reshaped. Which plastic should they choose?
A company is looking to reduce the environmental impact of its packaging by using a material that can be repeatedly softened and reshaped. Which plastic should they choose?
If you melt two distinct thermoplastic polymers together, what outcome is MOST probable regarding the properties of the resulting material?
If you melt two distinct thermoplastic polymers together, what outcome is MOST probable regarding the properties of the resulting material?
If you needed to optimize the 'cooling cycle' in injection molding, what action would MOST directly influence and shorten this phase?
If you needed to optimize the 'cooling cycle' in injection molding, what action would MOST directly influence and shorten this phase?
Flashcards
What is a plastic?
What is a plastic?
Materials composed of large molecules which are synthetically made or modified.
Thermosetting plastic
Thermosetting plastic
A type of plastic that does not melt when heated; it turns to ash and cannot be reshaped.
Thermoplastic
Thermoplastic
A type of plastic that softens when heated and can be reshaped into new objects.
Extrusion
Extrusion
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Injection Molding
Injection Molding
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Blow Molding
Blow Molding
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Melt Spinning
Melt Spinning
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Thermoplastic
Thermoplastic
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Thermoset Polymers
Thermoset Polymers
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Elastomers
Elastomers
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Study Notes
- Plastics are materials composed of large molecules that are synthetically made or modified
- Thermosetting plastics and Thermoplastics are the two main types of plastic
- Thermosetting plastics do not melt when heated and turn to ash, and therefore, cannot be used to make new objects
- Thermoplastics soften when heated, can be reshaped, and can be used to make new objects
History of Polymers
- 1942: Polyester was used for clothing and boat hulls
- 1942: Polyethylene was utilized for milk jugs
- 1943: Fluorocarbon was used for industrial gaskets and non-stick liners
- 1943: Silicone was used for gaskets, tubing, and utensils
- 1947: Epoxy was used for glues
- 1948: Acrylonitrile-Butadiene-Styrene was used for luggage
- 1954: Polyurethane or Urethane was used for foam cushions, shoe soles, and wheels
- 1956: Acetal was used for automotive and toilet parts
- 1957: Polypropylene was used for living hinges and safety helmets
- 1957: Polycarbonate was used for water bottles and eye protection
- 1964: Ionomer was used for golf balls and skin packages
- 1964: Polyimide was used for gears
Plastic Uses
- Plastics are used in automobiles for weight reduction (mileage)
- Plastics are used in aviation, such as the 767/787 and Voyager/Space Ship One
- Plastics are everywhere
Plastic Intensive Vehicles
- Corvette
- Lotus
Medical Plastics and Composites Use
- Containers like bottles and bags
- Drug delivery systems, including IV bags, syringes, tubing and surgery tools
- Implants and artificial skins
- The use of plastic materials in the medical field amounts to about $4 billion in 2000 (US)
Classification of Polymers
- Polymers
- Thermoplastics
- Thermosets
- Elastomers
Extrusion Process
- Extrusion involves forcing a melted plastic through a "die" or nozzle
- Dry plastic powder or granules endure heat and pressure as they go through an extruder
- Parts are fed to a hopper with polymer pellets, a screw then rotates to move the molten polymer through heaters
- Extruded products include auto trim, vinyl window frames, house siding, pipes, tubing, fibers, films (bags, coverings, and laminates), and coatings
Injection Molding Process
- Injection molding is the most important commercial method for transforming thermoplastics into useful products
- Injection molded items are computer keyboards, plastic model or hobby kits, plastic bottle caps, circuit breakers, power tools, and tableware
- The process includes a filling cycle, cooling cycle, mold opening, and part ejection
Melt Spinning
- Melt spinning is a process that utilizes a heating plate, gear pump, filter pack, spinneret, cooling air, roller, and winder
Blow Molding Process
- Blow molding technology was adapted from the glass industry for molding hollow containers from thermoplastic materials
- Widely known blow molded objects are bottles , jars, and containers for beverage, cosmetic, medical, pharmaceutical, and home product industries
- Step 1: Melted polymer material is injected between two closed halves of a mold
- Step 2: Air enters the cavity to push the polymer into the shape of the mold
- Step 3: The mold opens, and the hollow product is removed and trimmed
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