I have a USB memory stick that I use to record TV and its permanent home is the USB plug of the TV set. However, after a period of time (which I do not recall the length), the plastic casing has become somewhat sticky. There is no evidence of any foreign substance on the device, and it would seem that the plastic itself has become degraded. I’m curious about what materials would degrade in such a manner.
KJW said:
I have a USB memory stick that I use to record TV and its permanent home is the USB plug of the TV set. However, after a period of time (which I do not recall the length), the plastic casing has become somewhat sticky. There is no evidence of any foreign substance on the device, and it would seem that the plastic itself has become degraded. I’m curious about what materials would degrade in such a manner.
What brand?
or is it Genetic, no branding
CrazyNeutrino said:
What brand?or is it Genetic, no branding
Essentials, which I think is Woolworths.
I also come across a pair of manicure scissors that I never use with plastic coated handles that have also become sticky. Washing the plastic with a household cleaner doesn’t remove the stickiness.
KJW said:
CrazyNeutrino said:
What brand?or is it Genetic, no branding
Essentials, which I think is Woolworths.
I also come across a pair of manicure scissors that I never use with plastic coated handles that have also become sticky. Washing the plastic with a household cleaner doesn’t remove the stickiness.
Why not take them to Woolworths, see what they say?
doing a google search this seems to be a common problem with plastic products made in China. dunno what types of plastics they are though.
KJW said:
CrazyNeutrino said:
What brand?or is it Genetic, no branding
Essentials, which I think is Woolworths.
I also come across a pair of manicure scissors that I never use with plastic coated handles that have also become sticky. Washing the plastic with a household cleaner doesn’t remove the stickiness.
Have noticed plastic degrading by becoming sticky, and can confirm that no amount of washing makes it better.
I’ve never known why, but my first guess is that the polymer is breaking down into shorter-chain versions of the same plastic.
I don’t know if this would work, or make things worse, but with spectacle frames made of acetate a quick careful wipe with acetone will restore the shine/polish. But you can’t leave it on, it melts the plastic. Not recommended for all plastics though, we only do it if we are pretty sure of the material.
ChrispenEvan said:
doing a google search this seems to be a common problem with plastic products made in China. dunno what types of plastics they are though.
prastics…
mollwollfumble said:
my first guess is that the polymer is breaking down into shorter-chain versions of the same plastic.
I would say that is probably a good guess. Short-chain polymers do tend to be high-viscosity liquids (ie sticky). The environment wasn’t such that hydrolysis would be a mechanism of degradation (many plastics are dehydration products).
a piece of sticky plastic
(someone had to do it)
maybe cover the usb port with masking tape and then paint glue over the sticky bits
look for a glue for plastics
then when the glue dries
paint over it with an acrylic paint
buffy said:
I don’t know if this would work, or make things worse, but with spectacle frames made of acetate a quick careful wipe with acetone will restore the shine/polish. But you can’t leave it on, it melts the plastic. Not recommended for all plastics though, we only do it if we are pretty sure of the material.
I had not tried a more aggressive solvent. I know acetone is one of the better solvents for organic compounds.
CrazyNeutrino said:
maybe cover the usb port with masking tape and then paint glue over the sticky bitslook for a glue for plastics
then when the glue dries
paint over it with an acrylic paint
I’m still using the device.
Maybe I should try WB&D. :-P
some sites offer tips to repairing flash drives
flashdrivepros
wikihow
How to Repair a USB Flash Drive
alternatively take it out of the plastic case and build a wooden case around it like this one
http://www.ebay.com/itm/16GB-Wooden-USB-2-0-Flash-Pen-Drive-Memory-Storage-Oval-U-Disk-Wood-Case-/152225435322
Have a quick look here to see if there’s something you recognise.
https://en.m.wikipedia.org/wiki/Polymer_degradation
“Today there are primarily seven commodity polymers in use: polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polystyrene, polycarbonate, and poly(methyl methacrylate) (Plexiglas). These make up nearly 98% of all polymers and plastics encountered in daily life. Each of these polymers has its own characteristic modes of degradation and resistances to heat, light and chemicals. Polyethylene, polypropylene, and poly(methyl methacrylate) are sensitive to oxidation and UV radiation, while PVC may discolor at high temperatures due to loss of hydrogen chloride gas, and become very brittle. PET is sensitive to hydrolysis and attack by strong acids, while polycarbonate depolymerizes rapidly when exposed to strong alkalis.
For example, polyethylene usually degrades by random scission—that is by a random breakage of the linkages (bonds) that hold the atoms of the polymer together. When this polymer is heated above 450 Celsius it becomes a complex mixture of molecules of various sizes that resemble gasoline. Other polymers—like polyalphamethylstyrene—undergo ‘specific’ chain scission with breakage occurring only at the ends; they literally unzip or depolymerize to become the constituent monomers.”
There is also photo – induced degradation.
I vaguely remember that there is one commonly used plastic that is so unstable that it has to be loaded with a very large number of proprietary additives to be stable enough to sell. Get the additives wrong and it breaks down very rapidly.
If you feel up to it, you can test which type of plastic it is by cutting off a little and holding it in a gas flame. Here we go, look at this website. I’ve used it to identify a urea based plastic for example. http://www.boedeker.com/burntest.htm
some tips from instructables
http://www.instructables.com/id/DIY-Teak-USB-drive/
http://www.instructables.com/id/Tiny-Wooden-USB-Drive/
http://www.instructables.com/howto/replacing+usb+covers/
http://www.instructables.com/id/USB-2/
Lots of polymers degrade over time as a result of of contact with things like solvents, gases, heat and light; it is a common problem,
my bet for a usb stick is a combination of solvents (in the form of oils and water) on your fingers combined with high temperatures associated with being plugged into a computer.
diddly-squat said:
my bet for a usb stick is a combination of solvents (in the form of oils and water) on your fingers combined with high temperatures associated with being plugged into a computer.
Nah, it’s Big Petrochemicals spraying contrails to slowly dissolve plastics and make us buy more.
party_pants said:
diddly-squat said:my bet for a usb stick is a combination of solvents (in the form of oils and water) on your fingers combined with high temperatures associated with being plugged into a computer.
Nah, it’s Big Petrochemicals spraying contrails to slowly dissolve plastics and make us buy more.
I thought postie was was on facebook at the moment…
Could be a cross linked polymer and the heat is causing cross linking breakdown, the stickiness is due to the large unlinked molecules of polymer, like a rubber tyre – heats up and gets sticky.
KJW said:
I have a USB memory stick that I use to record TV and its permanent home is the USB plug of the TV set. However, after a period of time (which I do not recall the length), the plastic casing has become somewhat sticky. There is no evidence of any foreign substance on the device, and it would seem that the plastic itself has become degraded. I’m curious about what materials would degrade in such a manner.
its probably a symptom of endless cost cutting in the process
Just to bump my own post.
“Test which type of plastic it is by sawing or slicing off a little and holding it in a gas flame. Here we go, look at this website. http://www.boedeker.com/burntest.htm
If you don’t have natural gas on in your house, even a cigarette lighter will do.
The plastic is determined using the odour, colour of flame, whether it drips, how quickly it burns, and whether it continues to burn after the gas flame is removed, whether it generates sparks or soot, and whether it floats on water. Putting it together you can identify virtually any commercial plastic.
Last time I had something made of plastic that went sticky over time I threw it out. It’s not something that can be easily fixed – unless you happen to have an appropriate catalyst handy. For example, polyester thermoset plastics catalyse using benzoyl peroxide, which you can pick up at some hardware stores.
mollwollfumble said:
Just to bump my own post.“Test which type of plastic it is by sawing or slicing off a little and holding it in a gas flame. Here we go, look at this website. http://www.boedeker.com/burntest.htm
If you don’t have natural gas on in your house, even a cigarette lighter will do.
The plastic is determined using the odour, colour of flame, whether it drips, how quickly it burns, and whether it continues to burn after the gas flame is removed, whether it generates sparks or soot, and whether it floats on water. Putting it together you can identify virtually any commercial plastic.
Last time I had something made of plastic that went sticky over time I threw it out. It’s not something that can be easily fixed – unless you happen to have an appropriate catalyst handy. For example, polyester thermoset plastics catalyse using benzoyl peroxide, which you can pick up at some hardware stores.
Although the scissors handle would be good to fix, my main interest is in the chemistry of the stickiness. The two objects are in somewhat different environments which provides some information (by elimination) about what could be causing the problem.
KJW said:
mollwollfumble said:
Just to bump my own post.“Test which type of plastic it is by sawing or slicing off a little and holding it in a gas flame. Here we go, look at this website. http://www.boedeker.com/burntest.htm
If you don’t have natural gas on in your house, even a cigarette lighter will do.
The plastic is determined using the odour, colour of flame, whether it drips, how quickly it burns, and whether it continues to burn after the gas flame is removed, whether it generates sparks or soot, and whether it floats on water. Putting it together you can identify virtually any commercial plastic.
Last time I had something made of plastic that went sticky over time I threw it out. It’s not something that can be easily fixed – unless you happen to have an appropriate catalyst handy. For example, polyester thermoset plastics catalyse using benzoyl peroxide, which you can pick up at some hardware stores.
Although the scissors handle would be good to fix, my main interest is in the chemistry of the stickiness. The two objects are in somewhat different environments which provides some information (by elimination) about what could be causing the problem.
What is causing the problem is already known. It’s due to poor quality control in the addition of additives during the plastic’s manufacture leading to “chain scission”. As for the chemistry of the stickiness, do the burn test. Once you know which plastic it is, you can figure out whether the degradation is thermal, UV, oxygen or ozone catalyzed.
If you want to go further, then look up
https://en.wikipedia.org/wiki/Stabilizer_for_polymers
to find out which stabiliser was mishandled during the production process.
KJW said:
I have a USB memory stick that I use to record TV and its permanent home is the USB plug of the TV set. However, after a period of time (which I do not recall the length), the plastic casing has become somewhat sticky. There is no evidence of any foreign substance on the device, and it would seem that the plastic itself has become degraded. I’m curious about what materials would degrade in such a manner.
Found an item in my house with a similar problem. It’s an umbrella handle. It has the appearance of a rubber-like compound that hasn’t been properly vulcanised. Insufficient or improperly mixed thiocarbanilide additive.
Does yours look like that, or does it look like a hard plastic? I’ve seen both.
mollwollfumble said:
Found an item in my house with a similar problem. It’s an umbrella handle. It has the appearance of a rubber-like compound that hasn’t been properly vulcanised. Insufficient or improperly mixed thiocarbanilide additive.Does yours look like that, or does it look like a hard plastic? I’ve seen both.
Hard plastic. Also, they remain hard when they become sticky.