Reef Chemistry Question of the Day #231 Stability of Polyethylene

[Randy Holmes-Farley]

Reef Chemistry Question of the Day #231

Brute trash cans and many other containers we use in reefing are made of polyethylene. Which of the following situations (long term) would be expected to be most damaging to a polyethylene container such as a Brute trash can?

A. The super low pH of concentrated (37%) hydrochloric acid (muriatic acid; pH about -1)
B. The super high pH of 30% sodium hydroxide in water (pH about 15)
C. The highly hydrophobic character of diesel oil
D. Exposure to 2% ozone in air

Good luck!




















.














.

 

[SDReefer]

I'm going to guess C due to diesel oil's aromatic hydrocarbons.

 

[Grey Guy]

D for sure

 

[Newb73]

Following.

Been thinking about changing my auto top off Resovoir to acrylic for a while now.

 

[billw]

D

 

[dragon99]

It seems that ozone in air doesn't play well with PE, but I'm also seeing that diesel shouldn't be stored in PE long term... hmm

D, 2% ozone seems really high

 

[ksed]

D

 

[Centerline]

D

 

[zsuzsu]

gimme d

 

[rkpetersen]

Hmm, hydrocarbons and polyethylene is a big no no, especially aromatics, which can plasticize it. PE is generally resistant to O3, although that's a significant concentration.

Still -- I'll go with C. I think you'll have problems fastest with that one.

 

[ksed]

Jerry cans are made of polyethylene. You can store diesel in those.

http://www.scepterconsumer.com/

 

[MnFish1]

D

 

[Caseyoidae]

I want to say a but i think I may be missing something. I'll go with d just in case. There should be a reef jeopardy on here lol

 

[SDReefer]

Diesel oil is 25% aromatic hydrocarbons. According to the HDPE Chemical Resistance Guide, aromatic hydrocarbons are labeled as "U - Unsatisfactory." Ozone, on the other hand, is labeled as "O - some attack." If we're dealing with 25% aromatic hydrocarbons, wouldn't that cause more damage than 2% ozone?

 

[rkpetersen]

So I'm new here, how does this work? How long does each thread go before we get the official right answer?

 

[Randy Holmes-Farley]

So I'm new here, how does this work? How long does each thread go before we get the official right answer?

A few days, typically.

 

[Jeff Hall]

So your saying my tuperware ATO may not be the best choice?

 

[SDReefer]

So your saying my tuperware ATO may not be the best choice?

Well, I don't think you're storing Hydrochloric acid, Sodium hydroxide, diesel oil, or ozone in your ATO, so you should be fine, especially if it's food grade tupperware.

 

[Hitmans reef]

C would b more damaging to the container long term. I work in a shop with diesel everyday I have several jugs around the shop holding diesel which they do well they are also polyethylene .....but having said that these containers will start to drip either thru the PE valve or container lid after about a year or so of use.

Look at the cap and valve both over time the diesel will start to seep through

 

[IonicBond]

I'm going to say oxidation is the biggest risk factor for HDPE breakdown.