[Topic 8] Plastic Industry Flashcards
Are synthetic materials made from a wide range of organic polymers such as polyethylene, PVC, nylon, etc., that can be molded into shapes while soft and then set into a rigid or slightly elastic form.
Plastics
Any natural or synthetic organic compound consisting of a noncrystalline or viscous liquid that can be converted into polymers.
Resins
A substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits.
Polymer
Subunits of polymers
Monomers
Are combination of two or more materials with different physical or chemical properties.
Composite materials
Are plastics which are strengthened with fibers, fillers, particulates, powders and other matrix reinforcements to provide improved strength and/or stiffness.
Plastic composites
Is a manufacturing process of shaping materials into desired forms.
Molding
A matrix that dictates the shape and size of the final product.
Mold
Types of molding (4)
- Blow Molding
- Foam Molding
- Compression Molding
- Transfer Molding
Uses air pressure to transform plastic into hollow objects.
Blow Molding
Done by mixing a polymer with a gas under pressure, then allowing it to expand within a mold.
Foam Molding
Material is placed in a heated mold cavity and then a pressure is applied to force the material in contact with all the mold areas, and heat and pressure are maintained until the molding material has cured.
Compression Molding
The molding material is initially placed into a pre-molding stabilizing chamber. Then, under heat and pressure, the material is forced into the mold cavity.
Transfer Molding
It involves a chemical reaction that creates crosslinks between polymer chains, transforming the material from a soft or liquid state into a hard, infusible solid.
Curing
A heat treatment method used to eliminate any unacceptable stress that may result from the manufacturing process, improve dimensional stability, or increase the degree of crystallinity.
Annealing
Raw materials for plastic making (6)
- Filler
- Binder
- Catalyst
- Plasticizer
- Dyes and Pigments
- Lubricants
May be added to increase strength.
Filler
This is usually a resin or cellulose derivative used to bind molding composites.
Binder
Used to initiate the polymerization of monomers.
Catalyst
Are added to vary the properties of the cellulose derivatives and certain other thermoplastic resins to produce tough and resilient products.
Plasticizer
Added to give color of the plastic product
Dyes and pigments
used particularly in cold-molding compounds to facilitate the molding operation.
Lubricants
Inventor of Bakelite
Leo H. Baekeland
The first commercial plastic
Bakelite
Supply most of the basic needs for phenol, formaldehyde, dyes, solvents, maleic and phthalic anhydrides, and many other organic chemicals.
Coal mines and petroleum industry
They are obtained from fusible intermediates which, under the influence of heat, pressure, and a catalyst, undergo chemical changes of condensation and polymerization to form a rigid final shape.
Thermosetting resins
Once cured, it cannot be re-melted.
Thermosetting plastic
They are typically formed by the reaction of compounds containing at least two active hydrogen atoms and epichlorohydrin.
Epoxy resins
They are used to create products like boat hulls and electrical components.
Epoxy resins
Are made from phenolic and aldehyde compounds.
Phenolic resins
It is mainly used for circuit boards and other electrical applications due to its excellent electrical characteristics.
Phenolic resins
Are man-made elastomers with networks of oxygen and silicon atoms.
Silicone resins
It is mainly used in electrical insulations
Silicone resins
Mostly obtained from substituted derivatives of ethylene which can be made to polymerize under the influence of heat and catalysts.
Thermoplastic resins
They have linear and branched structures, which allows them to soften when heated and harden when cooled.
Thermoplastic polymers
These types of plastics can be heated and remolded repeatedly.
Thermoplastics
A plastic material made from the polymerization of ethylene monomer.
Polyethylene
The most produced plastic but is also the most difficult to manufacture.
Polyethylene
Cross-linking agent in the production of polyethylene.
Oxygen
Are synthetic materials made from compounds having the vinyl (-CH-CH2) group.
Vinyl resins
Fully acetylated cellulose is partly hydrolyzed to give an acetone-soluble product.
Cellulose acetate
It is made by the pyrolysis of ethylbenzene, which is synthesized from ethylene and benzene.
Styrene resins or monomeric styrene
PET or PETE
Polyethylene Terephthalate
HDPE
High-density Polyethylene
PVC
Polyvinyl Chloride
LDPE
Low-density polyethylene
PP
Polypropylene
PS
Polystyrene
Commonly recycled plastics (2)
- PET or PETE
- HDPE
Sometimes recycled plastics (2)
- PVC
- LDPE
Occasionally Recycled plastic (1)
PP
Commonly recycled plastic but difficult to do (1)
PS
Decomposition time of PET or PETE
5-10 years
Decomposition time of HDPE
100 years
Decomposition time of PVC
Never
Decomposition time of LDPE
500-1000 years
Decomposition time of PP
20-30 years
Decomposition time of PS
50 years
Examples of miscellaneous plastics (2)
- Shellac
- Lignin Plastics
Obtained from a resinous material secreted by an insect, which is native in India.
Shellac
Are made from woody materials.
Lignin plastics
Is the binding material for the cellulose in live plants and in a few plastics.
Lignin
