Chapter 24
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polymers designed to improve upon properties found within their natural counterparts
synthetic polymers
how did synthetic polymers originate? why is it important to know this?
synthetic polymers, like many other things in science, originated as an accident. it is important to recognize how greatly they have developed, their uses expanding from basic combinations of natural polymers to hydrocarbons and more.
how are properties changed in synthetic polymers? how do these methods compare to those of hydrocarbons? think about their composition: why do these similarities make sense?
synthetic polymers, like hydrocarbons, change their properties through chemical rearrangement (including the addition or reduction of branches) and substitution. these similarities are likely more prominent in synthetic polymers developed from hydrocarbons, although they may also apply to those that aren’t.
name the properties of plastic. why are they so prevalent in everyday life?
plastic is generally lightweight, resistant to blunt damage, strong, and waterproof, although these properties do vary depending on the polymers in use. humans, relying on a lifestyle of work and constant movement, find these qualities desirable because they reduce the amount of effort that we must put into everyday tasks.
name some common examples of synthetic fibers
nylon, polyester, acrylic, and polypropylene
why are synthetic fibers applicable to almost any situation?
they can be easily mass produced and their properties easily altered, allowing for wide coverage in needs.
nylons that are used for fireproof and bulletproof materials
aramids
what pattern does nylon mimic at the molecular level? why is this so?
nylon mimics silk, a natural polymer, at the molecular level. originally, nylon was created to serve as an easily-accessible alternative to silk, a very scarce material. this similar arrangement of polymers allows for similar properties between the two materials, considering that the molecular structure of polymers (and by extension hydrocarbons) determines the properties within it.
sticky synthetic polymers modified to fit specific needs
adhesives
name a few examples of adhesives, and briefly explain their usage
• industrial adhesives: used for cars, buildings, aircrafts and other structures • ultraviolet-cured adhesives: used by orthodontists to seal structures (like brackets) on teeth
name an example of a synthetic polymer that is also a surface coating, and a synthetic polymer that is elastic
surface coating: polyurethane (or varnish) elastic material: synthetic rubber
layers of synthetic polymers
composites
what do composites do, in terms of altering existing polymers? name some examples of each
composites typically involve the combination of two or more polymers for the purpose of neutralizing a negative property or to enhance a desired property in the material. a. fiberglass reinforces plastic, making it stronger b. glass fibers in plastic neutralize/account for material’s original brittleness
where are composites often used in industry? what kinds of composites are used in these situations?
industry, including the construction of automobiles, spacecrafts, and aircrafts. the materials making up these structures are typically lightweight and durable, since they play a large role in industry and require very specific conditions to perform at their best.