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[posted 01.10.2001]



SEVEN SYMBOLS EMBOSSED ON the surface of disposable consumer products tether modern Western civilization from slipping into the damnation of the Third Circle, the realm of Hell Dante reserved for lazy asses (though I believe he technically called it sloth). The seven titan categories are recognized by a triangular loop with arrows (or some modification of such) to indicate the material’s reyclability, an acronym to indicate which plastic it is and a number as a double failsafe.

Ignorance of the recycling esoterica is no excuse for achieving a 100 percent inability to put the plastic bottle in the receptacle next to the garbage can. The reward for such ineptness is to end up mired in a snake-infested inferno with a neverending supply of warm backwashed Mountain Dew, drunk from the same sticky clear plastic bottle day after day until the end of time. Not to get medieval and 1960s on you, but there is a certain karmic circulation manifesting itself on how comfortable each individual is based on the physical environment, aggregating and normalizing to an average comfort level per head in our civilization. If we take this average individual value over time, and we consider that the world’s population is increasing exponentionally, then if each of us doesn’t recycle at least some, life will become a real pain in the ass in our lifetime.

If we consider the proposition that recycling is an individual effort summing to one solid effort by civilization, and that by recycling we prevent life from becoming a pain in the ass (not to mention to prevent a funky aroma from all the landfills and incinerators that will exist), then we must consider recycling an important part of civic virtue.


“If we all do a little, we can all do a lot.”

This sometimes nauseating public service announcement is heard on American noncommercial radio in association with a variety of environmental causes.

Recycling is not a perfect art. Recycling plastics is tricky. But why?

A plastic is an organic polymeric solid. A plastic is carbon-based (_organic_) material combined in various quantities with other such elements as hydrogen, nitrogen, oxygen, sulfur, chlorine and boron, synthesized into long chains (_polymeric_) with carbon as the backbone and other so-called structural groups attached like tree branches. A common analogy used in science classrooms is that a polymer is like a giant bunch of spaghetti.

Plastics generally retain structural integrity in the temperature range of -100 degrees Celsius to 200 degrees Celsius. In this temperature range — roughly, as cold as it’s ever going to get anywhere on Earth and about as hot as one needs an oven to cook a Boboli — plastics are famous for their durability and strength.

Below this temperature range, plastics turn into glasses and shatter. A fun trick if you work in a profession in which you have access to liquid nitrogen is to coat a raquetball in it for a minute or so, then — wearing thick gloves and safety glasses — slam the ball into a tile or concrete floor and watch it shatter like Robert Patrick in Terminator 2. Above the temperature range, plastics melt or dissociate and eventually burn up (light a plastic beer cup on fire for a real world demonstration).

Why is recycling so difficult? The basic chemical truth is that most polymers act like Italian salad dressing when they are mixed together as liquids. They just don’t dissolve in one another at all. Recycling is the process of melting down discarded bottles and containers to remold them into new bottles and containers. This is fairly easy to accomplish with the pure six magic materials and a few “others,” but about 90 percent of the “stuff” out there in the world is made from organic material. Compared to plastic, glass, paper and metal are a piece of cake. America is really in a nacsent recycling Ur considering the infinite number of plastics that can be produced and the relative newness of the plastics industry.


The fact remains that recycling is a pain in the ass. More important however than the common New Year’s Eve resolution-style effort of the individual consumer/waster is the actual technology behind recycling each specific plastic. In the immortal words of George Carlin, man was put on Earth to make plastic. I can hear the breathy baritone of the DeBeers spokesvoice now: “A plastic is forever.”

Accepting this as true, it might pay to get to know your everyday plastics. A list says it all.

1 — poly(ethylene terephthalate) or PET 2 — high density poly(ethylene) or HDPE or PEHD 3 — poly(vinyl chloride) or PVC 4 — low density poly(ethylene) or LDPE or PELD 5 — poly(propylene) or PP 6 — poly(styrene) or PS 7 — “other”

Category seven — other — is reserved for materials that are making headway in the recycling industry but are not yet produced in such massive quanities as to warrant their own categories. It is also important to emphasize that just because a plastic is recycl_able,_ that doesn’t mean that it’s made from recycl_ed_ plastic.


PET is first on the list. It’s sometimes abbreviated as PETE, equally easy to remember because your brother and/or neighbor has the same name. One Whinfield and Dickson discovered this material in the 1940s. The stuff from which the regal two-liter soda bottle is made — in the parlance — is produced from a two-step condensation reaction of the dimethyl ester of terephthalic acid and ethylene glycol. Sadly, this discovery was not at that time heralded by the media, which tended to focus on issues like World War II, Communist subversives and Humphrey Bogart films.

This lack of limelight did not deter its development into a cheap and durable plastic. The U.S. patent office issued pat. no. 2,465,319 to du Pont in 1949, and in the subsequent two decades, PET became known under different monikers in the synthetic clothing and carpet fiber industry: Dacron, Amilar, Fiber V, Diolen, Enkalene, Fortrel, Tergal, Tental, Terlenka, Trevira and Mylar.

Soda containment really makes PET a profitable material. Its introduction into the market in the 1980s — along with the high-quality soda containment supplied a decade earlier by the exploding field of aluminum cans — saw the demise of the glass bottle. (Which means, sadly, that soda companies don’t make the eight-pack of 16-oz. glass bottles any more. Those are the kings of all soda containment as far as a satisfying drink is concerned. Nothing beats an ice cold Dr. Pepper in a glass bottle on a dense-hot day.)

Polyester shirts, overhead transparencies and packaging materials were important PET products as well — but recycling efforts were focused on bottles because of the sheer quantity produced. So, to all the urban hipster Diet Coke drinkers reading this, thank your lucky stars for PET. Without it, you might not have the ubiquitous 20-oz. bottle now found everywhere anything is sold.

PET bottles are also commonly advertised as “unbreakable” food containers — an alternative to that pesky glass ketchup bottle with its tendency to fall right off the over-packed refrigerator shelf and cause a messy, messy ketchupy mess. Cheap liquor, cooking oils, Pine-Sol, peanut butter, mouthwash, shampoo, conditioner and now even select brands of macrobrew beer all use PET bottles.

PET could be confused with polycarbonate. Both are tough, clear plastics, but polycarbonate is generally a stronger and more expensive material. It supplies the clear plastic housing of the Macintosh G4, for example.

DuPont makes a high-tech plastic in this category called “Rynite® PET thermoplastic polyester resin.” Forget about soda bottles, folks; this stuff is used for housings and covers, support brackets, bicycle components, pump parts, electrical sensor housings, motor parts, lamp sockets, terminal blocks, switches, bobbins, oven handles and control panels, small appliance housings, automotive support brackets and luggage racks.

Finally, PET is a tough bastard to recycle. It tends to dissociate before it melts. This is not a favorable quality to have as a recyclable product, considering some of the noxious shit that organic materials can emit.

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Next Time:

Poly(ethylene) takes over the milk business in the 1970s! And glass tries to reclaim the milk industry in the late 1990s in a showdown at Whole Foods.
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mark e. greene is working on his ph.d. in materials science and engineering at northwestern university. he lives in chicago and mindlessly babbles on to no logical conclusion about the impact of materials on mankind to his friends. he hopes to hold many patents for new materials of his own design and creation so that he may have an impact on mankind. woo! haha haha….