---
title: "The characters of plastics"
slug: the-characters-of-plastics
url: https://listedarticles.com/articles/the-characters-of-plastics
canonical_url: https://yarchive.net/blog/plastics/
content_type: essay
language: en
published_at: 2026-10-04T05:15:03.514Z
updated_at: 2026-10-04T05:15:03.514Z
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publisher: "yarchive.net"
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topics: ["science", "engineering", "hardware", "history"]
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reading_minutes: 7
citation: "yarchive.net. \"The characters of plastics.\" 4 Oct 2026. https://yarchive.net/blog/plastics/ (all-rights-reserved)"
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# The characters of plastics

> An essay comparing commodity and engineering plastics to literary character types—why “polymer” is often marketing spin, and how chemistry shapes toughness, clarity, heat tolerance, and reputation.

# The characters of plastics

“It’s made of plastic” is a common put-down. Marketers selling
higher-end bits made of plastic (like gun parts) try to evade the
stigma by calling it “polymer”, but that’s just a stupid
euphemism: every plastic is a polymer, though not every polymer
is a plastic. The word “polymer” says nothing to indicate that
this might be a superior sort of plastic. Yet there are superior
sorts; plastics vary widely in their characters. Some analogies
between plastic and human characters:

Polyethylene, polypropylene: Snow White (simple, pure, weak).
These are the cheapest and most common plastics, and are made of
just hydrogen and carbon atoms. Ethylene (two carbons and four
hydrogens) is polymerized to make polyethylene, and the quantity
of ethylene made each year is measured in cubic miles. They can
of course have pigments added to them to give them color, but are
commonly used in uncolored, nearly-pure form. Chemically they
are unreactive, which makes them good for containers of all
sorts; they are even used for chemistry beakers. That same
unreactivity makes them very hard to glue, and means they don’t
deteriorate with time. Leave them out in sunlight, though, and
the UV quickly weakens them to where they crack easily.

Nylon: Arnold Schwartzenegger (strongman). Plastic nuts and
bolts, which need to be strong, are usually nylon, as is
monofilament fishing line and womens’ hosiery (delicate, but
still strong for its weight). Nylon adds nitrogen to the list of
atoms it contains; it’s chemically known as a “polyamide”, a
class which also includes proteins.

Nylon with 30% glass fiber reinforcement: Arnold Schwartzenegger
on steroids. It’s as strong as cast aluminum (though extruded
aluminum can be much stronger). When guns are made of plastic,
this is usually the plastic they use; likewise for the plastic
housings of electric drills and other power tools.

Polycarbonate: Achilles (warrior with a fatal weakness).
Polycarbonate is what they make bulletproof windows from, and
safety glasses, and the transparent fronts of car headlights. Its
weakness is chemical attack: a splash of acetone, and it
instantly “crazes”, a network of fine cracks appearing across its
surface as built-in stresses are relieved. (If the part has any
built-in stresses, that is; molded parts probably do, but flat
sheets might not.) Polycarbonate is often protected by a surface
coat to block chemical attacks. It’s the main plastic that gives
off the notorious bisphenol A (BPA), which is probably not so bad
as it’s reputed to be. But it still doesn’t make sense for food
containers to be made from polycarbonate, since they don’t need
to be bulletproof and polycarbonate is pricey.

Polyvinyl chloride (PVC): Dr. Jekyll and Mr. Hyde (a character
who varies wildly depending on which drugs he takes, with more
than a bit of evil in him). PVC is normally rigid, and is used
in that form for house siding and sewage pipes, but can be pumped
full of plasticizer to make it flexible; in that state it’s used
for inflatable boats, shower curtains, imitation leather, and
even sex toys. In pure form it’s not a stable chemical; its
staying good depends on added “stabilizers”, which themselves can
be somewhat evil: they often contain the toxic element lead,
which normally is locked in the plastic but is unleashed when the
plastic deteriorates or is burned. Burning it also gives off a
variety of toxic chlorine-containing substances. The
plasticizer, if used, evaporates away over years (in cars,
landing on the inside of the windshield and producing an annoying
haze which has to be wiped away), and eventually the remaining
plastic gets brittle and cracks. The plasticizer is often a
phthalate, another notorious class of chemical and also probably
not as bad as popular repute would have it, but still not good
for you and a pain to clean up. (People commonly regard soft
plastics in cars as good and hard ones as bad and cheap, but I
don’t think they’ve made the connection between having soft
plastics around and needing to clean off the inside of the
windshield, or for that matter having phthalates in the air they
breathe when getting into a car on a hot day.)

Polyurethane: an android from the movie Blade Runner (strong,
versatile, dangerous, doomed). Polyurethane can be made either
hard or flexible, with the flexible varieties used to make
rubbers and foams, but polyurethanes have a tendency to decide
“now it’s time to die”, losing almost all of their strength,
with foams crumbling or turning to goo and rubber parts cracking.
They are made using isocyanates, in a reaction which could be
thought of as Nazi chemistry since it was in fact invented in
Germany during that era and since isocyanates are quite toxic.
(That’s just a resemblance, of course; in reality Nazi ideology
had nothing to do with chemistry.) Though toxic (methyl
isocyanate killed thousands of people in the Bhopal disaster),
isocyanates are not cyanides (which are even worse), and in
finished polyurethane there are only traces of isocyanates left,
though they might be the cause of the annoying smell that new
polyurethane foam often has. But burning polyurethane does
produce some hydrogen cyanide, and polyurethane foam burns
unusually vigorously, unless it’s been treated with flame
retardants, which thus have been mandated by law in some places
but which themselves might be a health issue.

Bakelite, aka phenol-formaldehyde: well, nobody really comes to
mind as a corresponding character, but it’s rigid, brittle, and
can take a lot of heat. Bakelite was one of the first plastics,
and is thermosetting: it doesn’t melt but rather has to be formed
from its ingredients (phenol and formaldehyde) into its finished
shape (requiring a mold, heat, and pressure). With it we’re back
to things that contain only the safer elements (carbon, hydrogen,
and in this case oxygen). Phenol and formaldeyhde are each
nasty, but their nastiness is consumed when they react together.
Bakelite’s brittleness can be mitigated by using appropriate
fillers, particularly fibrous ones. Its heat resistance is such
that, mixed with high-temperature fibers, it is used for heat
shields for reentry from space (which burn away but do so slowly
enough that they don’t burn through). It also sees a lot of use
in things like electrical circuit breakers, where other plastics
might melt into a blob and let their metal parts short-circuit.

Polystyrene: Joe Sixpack (common, cheap, weak, nasty). It’s not
heat-resistant, not chemical-resistant (it dissolves in a wide
variety of solvents), and is brittle. But it can easily be blown
into a foam (styrofoam), which because of the bubbles is a good
insulator; being a foam also mitigates its brittleness. When
heated it de-polymerizes and gives off styrene, which has a
distinctive acrid smell. It can be improved into “ABS” by adding
large proportions of acrylonitrile and butadiene into the
polymerization process; ABS has the same distinctive smell when
heated but is considerably tougher, making it suitable for a wide
variety of consumer products (though it’s still much weaker than
nylon). Legos are ABS. If there’s a plastic which really
deserves the putdown “it’s made of plastic”, it’s ABS: it’s
common enough to be the sort of thing people think of when they
hear “plastic”, and is generally mediocre. But as human
analogies go it’s a step above Joe Sixpack; call it Joe Blow.

Teflon: Queen Victoria. “Nobility” in chemistry means a lack of
reactivity, an immunity to chemical attack; “noble metals” are
noble not because they’re expensive, but because they snootily
look down their noses at other chemicals and refuse to have
relationships with them. In plastics it’s harder to get nobler
than teflon (polytetrafluoroethylene; PTFE), which differs from
polyethylene by having all its hydrogens replaced with fluorines,
which are much more difficult to dislodge. Fluorine chemistry
being a difficult and dangerous sort of chemistry, PTFE doesn’t
come cheap. It’s used to coat nonstick pans, where its
nonreactivity translates into things not sticking to it. As best
I can tell (though information on this is scarce), even the newer
“ceramic” nonstick coatings often have an imperceptibly-thin
layer of a molecule with a highly-fluorinated tail that resembles
PTFE; the ceramic gets the publicity but the highly-fluorinated
chemical does the work of making the coating nonstick… until it
wears off, which because of the thinness of the layer happens
more quickly than it does with the older sort of pan which has a
visible layer of PTFE. (Modern nonstick pans are often regarded
with suspicion; but the old mainstay in that department, cast
iron, gets its nonstickness by being “seasoned”: coated with a
layer of burnt, polymerized oil, no doubt containing many
carcinogens.)

Those are just some highlights of a complicated subject; I
haven’t even mentioned some major plastics, and there are a host
of minor ones, as well as innumerable subvarieties of the major
ones. (Take polyethylene, normally weak, react it until the
molecular chains are long, then stretch it until they are
aligned, and you get an extremely strong fiber, suitable for
high-strength ropes or bulletproof vests: not Snow White but
Wonder Woman.) With such a varied cast of characters, it’s a
pity that they all get lumped together as “plastic” in common
usage. I suppose it’s somewhat inevitable, since you can’t just
look at a piece of plastic and tell what sort it is. But more
public awareness of the differences would be nice.

 

 
 

 
 
 
 
 
 
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