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Melting temperature tests

This topic contains 25 replies, has 18 voices, and was last updated by  Nick 3 weeks ago.

2
Dave Hakkens davehakkens

Melting temperature tests

25/01/2016 at 21:24

There are different types of plastic and each plastic has its own melting temperature. You can easily find this online. However there is a big difference between the melting range between different temperatures, does it get liquid when it melts and what if you burn it? There a re a lot of stages the material can be molded. We want to visualise this. Making it easier to understand the behaviors of plastic on a specific temperature.
Plan: Make a few simple molds which will be filled with 50 Gram of Plastic(from different types) They will be heated for 40 minutes at different temperatures to see how it behaves

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warrior
28/01/2016 at 23:47
3

Took a bit before I figured out a consistent workflow i can keep repeating. I need this to make sure its only the temperature that changes, and nothing else. Got a good routine, now lets start melting

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warrior
04/02/2016 at 23:05
3

This turns out the be more works than expected. But keen on getting it done, very interesting to see the behaviours of the different types

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warrior
11/02/2016 at 21:21
4

Finished all the experiments from 130 to 260 degrees. Useful that its a very clear overview of the different properties at certain temperatures. Next will turn it into a document which is easy to share with you guys. Hopefully it will be useful for others!

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new
28/02/2016 at 04:42
0

Dave,

What would you say is the best temperature to make PET malleable?
My senior design team is making a similar, automated machine, to recycle from home.

Thanks

warrior
29/02/2016 at 00:43
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Depends a little bit what kind of technique/machine you are using. The metling temperature is around 260 degrees. However compared to others types of plastic with PET this is very crucial. Couple of degrees above or below make it unnamable –is that a word? You got a picture of your machine?

new
06/05/2016 at 09:45
1

hi Dave, how long does it take to melt once temperature is set? how to know once it has melted and can turn off the oven.

starter
15/06/2016 at 03:35
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This post has been wikified and added to the Plastics Overview.

helper
22/01/2017 at 19:13
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The link above is dead^
Has the document been created yet? I am currently struggling to find useful information on these in general.

helper
08/03/2017 at 00:12
1

in donwload you should find this table

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starter
20/03/2017 at 16:53
3

Does melting plastic emit toxic gases or something? Or only when melted at a certain temperature? Does this add to our carbon footprint

new
23/03/2017 at 06:01
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Where I can get melting temperature table?

warrior
22/04/2017 at 21:44
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@putripewe, here is the link to Download the files – the table is in the last folder “5. Create” 🙂

starter
07/07/2017 at 11:56
2

I am interesting in this question.

Does melting plastic emit toxic gases or something? Or only when melted at a certain temperature?

Could somebody answer please? Thank you!!

starter
04/12/2017 at 22:09
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this is very helpful! love the pictures, so much easier to grasp with pictures 😉

starter
04/12/2017 at 22:12
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ditto! feel like this information is probably easily available for people who understand these things, but for someone with no chemistry background, i don’t even know where to look to get answers!

starter
04/12/2017 at 22:14
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also interested in this… ‘bump’ 🙂
if anyone knows where we can get information about this, be a dear and post a link pretty please!

Does melting plastic emit toxic gases or something? Or only when melted at a certain temperature?

new
20/01/2018 at 06:18
3

Dave:

I have considerable experience with extrusion of incompatible plastics (polymers), such as where certain plastics are difficult to sort out. Ideally you want to combine polymers than have similar polarity, from a chemistry standpoint. But that’s not always possible.

Certain polymers are not compatible under ordinary circumstances, so we use “coupling agents” or compatibilizers. Some of the more popular are maleic anhydride (MA), titanium/zirconium chemistry such as Ken React, and ethylenevinyl acetate (EVA) often with glycidylmethacrylate / butyl acrylate such as DuPont Elvaloy 4170.

I favor Ken React CAPOW by Kenrich, typically used at less than 1% by weight. Really ugly incompatibilities might use up to 2% Ken React. We mix it up a suspension in alcohol (keep shaking it) and spray it over the mixed plastic grind, tumbling it to get a more even mix, then feed it into the extruder. A bit lower temperatures than normal and a bit more torque work best. Some characterize this process as “Reactive Extrusion”, since a chemical / physical reaction is taking placing under high torque shear stress and heat.

I’ll post a polymer polarity chart for all.

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new
20/01/2018 at 06:25
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Looking back that chart might be a bit confusing to some as it includes plasticizers (chemistry to soften plastics generally).

So I deleted the plasticizers to make it simplier. Here’s the new chart:

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starter
17/02/2018 at 23:13
0

Hiya, I’m struggling to find the temp chart. Is there a valid link?

warrior
17/02/2018 at 23:42
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@geezergarage
Have a look at @katharinaelleke ‘s post a bit above^^ 😉

helper
18/02/2018 at 05:05
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@flo-2

that link does not work anymore

warrior
18/02/2018 at 18:03
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@basman @geezergarage
oh yeah, true! Here’s the most recent one: https://preciousplastic.com/en/videos/download.html
Have fun! 😉

starter
03/05/2018 at 00:37
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Hi all:

I am struggling to understand the message of @blueholediver. Thank you very much for the chart by the way. But honestly, don´t get the use of “coupling agents”! jeje

In my case, I am just starting and while structuring the plan, I am searching about the use of plastic weathered by sun and sea water because I would like to reintegrate some of the debris found at beaches and the sea.

I understand that plastics already very weathered would be difficult to clasify by types, so the temperture would be also no determined. Apart of that obstacle, somebody knows about the loss of properties among plastics while weathering and some alternatives to reuse them?

Thank you,

 

 

new
19/10/2018 at 05:33
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hi Dave, thanks for this wonderful project.

What do you know about the temperatures and speeds appropriate for the filament extrusion for 3d printers?

thank you very much again.

helper
25/10/2018 at 22:00
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This is wonderful, however I’m having trouble interpreting the results.

It seems that once the temperature is sufficiently above the melting temp, the inside is too runny and oozes out when laid on its side, rather than keeping its shape.

I suppose the goal, in order to conserve energy (and $$), is to use a temperature that is minimally sufficient to melt the plastic completely. However, especially in compression molding of larger parts, air pockets are a risk.

So, my question is: is there any problem with melting plastic above its melting temperature in order to make it less viscous, so long as you don’t burn the plastic?

To be specific, HDPE seems to form a smooth block around 150. Is there any harm in going to, say, 170?

A side note: a document in the Precious Plastic Kit lists HDPE’s melting temp from 130-137, and PP at 168-175. But those temperatures seem too low when looking at these visuals – again, HDPE seems better around 150 and PP at 190.

Given this, I suppose the best practice is to just use this as a guideline and then experiment with each plastic that we have to find what works for our process?

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