Presentation on theme: "Introduction to Engineering Plastics. During this unit we will review: Classifications of Plastics, Characteristics of thermoplastics, Definitions of."— Presentation transcript:
Introduction to Engineering Plastics
During this unit we will review: Classifications of Plastics, Characteristics of thermoplastics, Definitions of polymers and polymerization, Thermoplastic processing, Types of thermoplastics, Basic applications of thermoplastics, Recycling plastics,
Classification of Plastics Since WWII, polymers have been the fastest growing segment of the chemical industry in the United States, A modern automobile contains approximately 200 pounds of plastics, Plastics are used for all types of products that we use everyday,
Classification of Plastics Major advantages of using plastics are: Light weight, Ease of fabrication, Lower processing temperature, Lower cost,
Classifications of Plastics There are two basic types of plastics available today, Thermoplastics, Polymers that soften when heated and regain their solid form when cooled, Thermosets, Can only be softened, or melted, once. Heating causes a thermoset to undergo a curing, or setting, reaction. It cannot be re- melted.
Thermoplastic Processing Extrusion Is a process for making a product by forcing a material through a die. Injection Molding Injection molding is a major processing technique for making thermoplastic products. During injection molding, molten plastic is forced into a mold cavity to form a product.
Thermoplastic Processing Blow Molding Utilizes compressed air to inflate molten plastic to conform to the the mold cavity. Used for making hollow containers such as milk containers, Rotational Molding Or centrifugal casting, utilizes a rotating mold cavity to form a hollow product,
Recycling Plastics A major concern of using any plastics is the impact on our environment, Plastics occupy approximately 20% of the space in our landfills, Thermoplastics can be remelted and reprocessed, Thermosets cannot,
Recycling Plastics The problem with thermoplastic reprocessing (recycling) is that the properties of the plastic material change if different types of plastics are mixed together. It is important to keep the types of plastics separated in any recycling program,
Internet Activity Lab Complete the Internet Activity on Plastic Resin Codes, and upload it to your instructor via the classroom website.