Durability Of Plastic

The plastic components in household appliance was not designed or intended to last. but I do have a plastic record player and portable radio bought in about 1965 that is still in perfect condition.

Plastics are formulated for a specific purpose. ABS - Acrylonitrile Butadiene Styrene for example is a very durable (recyclable) plastic.

I saw some ABS boxes capable of withstanding the harsh environment in a mine with high temperatures at deep levels. Even a Methane explosion did not cause much damage.

As part of the advertisement the manufactures performed a 2m drop test and submerged it in water(with electronics inside).

Alternatively open your cars bonnet and inspect the plastic components. The relays in my 1991 Camry (with 380000 km on the clock) has not reached their half-life yet.

In most new home construction, plastic boxes are used for electrical wiring devices. Plastic is used as a covering for electrical wires. Plastic is used for water, sewer and drains. Window frame systems are made of plastic. Even the wood used for framing, flooring and outdoor decks can be plastic; the right plastic for the right job.

Your question is too general in nature, and not well informed.

For every broken plastic part you can name, I'll name 10 that have survived their intended life cycle.

Some plastic parts may be used where they are not well suited, or under engineered for the intended function, but most do a fine job.

I've got a 1985 Chevy K5 Blazer with many plastic parts that still look and work like new. It has spent many years in the Arizona desert when it is 110°F outside.

Wow Lyn!

"For every broken plastic part you can name, I'll name 10 that have survived their intended life cycle"

... lame, absolutely lame.

Perhaps you can add some enlightenment to the topic, instead of empty criticism.

You assume "not subject to load or harsh environement, no direct sunlight, no water wetting, no chemical exposure etc, just normal home environement".

Reflected or diffuse sunlight contains plenty of UV.
Fluorescent lamps emit plenty of UV.
Home environment provides aerosol insecticide sprays, detergents, other chemicals.

The detergents in most home cleaning chemicals can kick the tripe out of many plastics not chosen for ESCR (environmental stress cracking resistance). Intelligently and responsibly specified plastics can easily outlast you! Casually specified plastics may have quite a short domestic life.

Mark Bingham
Relativity PL

No, not all plastics, just most of them.

In my experience, the most long-lived plastic is Teflon. I have Teflon antenna insulators that have been in the sun, rain, wind, snow, etc. for 40 years and show no signs of degradation whatsoever. On the other hand, Teflon is soft, so it would be almost useless for making gears or similar parts.

Bakelite is also quite durable, but it is brittle. I have a 1951 soldering gun with a Bakelite case. I think I replaced its broken case somewhere in the 1970's. It still works, although a few pieces of the case are missing.

There are many newer plastics, such as Delrin, that will probably have longer lives, but they are relatively expensive, so aren't used in your $50 printer...

Manufacturing processes are not perfect. I work in an industry in which thermoset vinyl is a big part of the business. Getting the correct ratio of plasticizer, pigment and the base vinyl is essential, as are curing time and temperature. It would be nice to be able to say that all these parameters are perfectly met for any given product, and quality control IS a big part of our business. But reality happens and products do occasionally get out the door which might have slight parameter discrepancies. And not everyone in the industry is as quality conscious as we hope that we are. So what you may be seeing might be partly quality control issues.