Are newer plastics more brittle?

The niece and her kids from Florida are visiting over Winter Break this winter and want the full “northern winter” experience. Was reasearching snow sleds, and there’s been a lot of complaints about the new plastic ones breaking after only a couple of uses. I saw a few unsourced statements that “plastics are more brittle” then when say I was a kid in the 80s now because of A) recycled materials being used B) smaller pellets being used, C) They can’t use some chemical making them like they used to.

I get that a $10 plastic sled is something you use until it breaks and then you just get another one, but I am curious about this, also wonder if the plastic used is the type that gets brittle over time, wondering if plastics really are more brittle now, how my 1980s sled that’s been sitting in the garage all these years would hold up compared to a new one I buy from Menards.

As a bonus question, I saw they have something all called “Snowboogie” sleds that look like a water boogie board with a slick bottom. Are these an improvement over your basic red pastic toboggan like have been around forever or is it just something cool looking to get parents to spend money on?

I can factually report on a little bit. Nylon is a common material used in injection molding products. If too much regrind is used in the mix, the parts do become more brittle. As I recall, when the mix went over 25% regrind this started causing some issues. The other things, is storage of nylon products in too low of a humidity can also cause brittleness.

More on regrind, click to read

Regrind is typical failed parts and especially runners. If you can remember back to getting games like Life, the parts in the box came still attached to the molding runners and had to be detached. Also commonly seen for model kits.

Recycled material should work similar to regrind, 100% recycled if nylon would be a fairly big problem, but I don’t think this is a practice. Who recycles nylon?

I don’t know the properties of any other plastics. But I would think there were some similar issues.

Nylon falls under Symbol 7 (OTHER) for recycling.

Reminder, this is FQ, please provide factual answers and not opinions.

I don’t think newer plastics are more brittle as they can still make them as hard or soft as they want and as thick as they want. I think it’s more a matter of the manufacturers not making them as thick as they used to to save a buck.

It’s not newer plastics; just cheaper ones. Those snow discs used to be made of the same kind of polyethylene still used for things like modern molded kayaks. It’s very impact and weather resistant. Those kayaks are pretty pricy for what’s essentially just 50 lbs of molded plastic. There’s no way you could price a snow saucer made of that material for under $20 now.

One thing I’ve learned from my interest in fountain pens is that there is a huge range of substances called “plastic,” so a lot depends on which specific plastic or at least which plastic family you’re talking about. Generalizations are probably not going to be very accurate for a very large percentage of plastics.

Those slick bottoms are good. We used to get them more as discs or flexible boards than sleds, but they worked well. Didn’t clog as much when the snow was heavy and wet.

This may be referring to chemicals like phthalates, which have been used to soften plastics such as PVC, but which may be an “endocrine disruptor” in the human body, and may cause cancers and reproductive issues. My understanding is that some manufacturers have been voluntarily phasing out the use of phthalates.

+1 for “wrong plastics used”.

Some years ago, I had a chinese scooter (scooter as: think Vespa, not kick-scooter) … and the plastic parts were extremely brittle, b/c the were made from the wrong (=cheaper?) kind of plastic.

A motocross-motorcycle has its fender made of plastic that can withstand an incredible amount of abuse and still pretty much bounce back … my scooter not so much … fell over once in the garage and I had substancial cracks in the plastic fenders.

So when using the right plastic, those are as good as ever. - but things coming out of china, often save pennies to a degree that they render a product inoperable after short time (b/c they are throw away items) and nobody files a claim - so in a way “poor quality” becomes good enough.

… and that might filter into this perception of plastics are poorer.

and as mentioned above: the lighter (less material) … the cheaper it gets … fwiw: I just held a pet beverage bottle in hand that I really needed to support it with my other hand, or it would have collapsed when pouring a glass, so thin was the plastic.

^ This.

Manufacturers using less plastic in an object to save themselves money and drive up profits.

I used to work for several manufacturing plants and was told this: A significant amount of money goes into the tooling and molds to manufacture an item, such as a unique bottle. Once you’ve done that, your costs are mostly materials, shipping, and a bit of labor. It is a big temptation for the owners (especially new owners who just bought your production line) to see just how far they can push cheaper materials and still have the tooling and molds work. If a cheaper, less durable plastic is available, but it requires thicker walls to be strong enough, the owner will definitely not find it cost-effective to change the tools and molds to make the product thicker. This is also true of molded parts in electronic equipment, toys, cooking implements, etc. Saving 5 cents using plastic D instead of plastic A really adds up.

Okay, years back, they woke up and decided that plastics shouldn’t lay around forever. They did something to them that now causes them to break down over time. Is that true for all plastics, and is that the reason why plastics seem to be much less resilient than we would like?

Sorry, if you’re asking me (and I’m not clear how your question relates to what I posted), I don’t know the answer. I had thought that such efforts as you describe were focused on single-use plastics (plastic cutlery and straws, single-use bags and wraps, etc.).

This isn’t true of all plastics. Manufacturers can buy all sorts of different resins and resins plus fillers (most plastic articles have filler in them). There may be specific examples that are made biodegradable, and at least some of those degrade by becoming brittle and crumbling during exposure to the sun – if you’ve ever tried to gather old litter, you’ve seen some of the plastic bags and whatnot just falling apart. But for plastics overall, no, there are plenty that aren’t made biodegradable.

I inferred “brittle” as being a form of vulnerability, so the thought was that it was a designed vulnerability so that the plastic wouldn’t last for too long of a time.

You may be right. On the other hand, long term use items still get discarded over time. It just takes longer.

Didn’t know this. I thought it was a law uniform to all plastics.

Nope! They don’t want your acrylic or polycarbonate windows to biodegrade, or your PVC pipes!

And especially not your bodily implants…

I guess I flunked my plastics engineering test. LOL

Now that the technical, factual answers are in, I’m too.

It seems to me over the past few years I’ve experienced plastic failure at an alarming rate. Numerous and varied household items from gripper handles to ladles to trash cans to spring clamps to SAK handles to game calls have snapped or cracked from ordinary use, out of the blue, usually leaving me in a bind. The plastic parts, that is.

I no longer have any trust in plastic items / components keeping over an extended period of time. It’s almost like they have an expiry date set in years, at most.

Constrast this to the wood, metal, glass etc. items in similar uses that are up to 100 years old, still in everyday use by me, and show no sign of giving up the ghost.

Out of necessity, I’m in the process of de-plastifying my life. I can’t afford not to.