Applying high pressure to paper causes it to heat up to the point that its cellulose fibers can undergo partial pyrolysis turning it into a brittle charred mess

Applying high pressure to paper causes it to heat up to the point that its cellulose fibers can undergo partial pyrolysis turning it into a brittle charred mess

Recommended For You

About the Author: livescience


  1. This clip comes from [a video by the hydraulic press folks that]( made it rounds here about year ago. This video came up on /r/askscience where someone asked what exactly happened to the paper. I got curious myself and looked into the question a bit. The short answer is that by pressing the paper so hard it started to heat up eventually the cellulose fibers started to break up at the molecular level (pyrolysis). Eventually this partially burned mess was compacted down into the brittle slab you see at the end.

    In case you are looking for a somewhat more detailed answer, below is my original answer from /r/askscience:


    1) Paper is largely made up of a forest of irregular [cellulose]( fibers, [as shown here at high magnification]( When pressure was first applied, the fibers became compacted together, but their internal structure did not significantly change.

    2) A further increase in pressure caused rapid local heating.

    3) The heating led to [pyrolysis](, i.e. a messy series of reactions that we throw together under the umbrella term “decomposition.” In the end what was probably left was a mess consisting of fibers in domains with different packing, some plastic-like patches, and bits of what is essentially char.

    This result is in line with what materials researchers saw when trying to melt cellulose. For example,take [this paper](^1, where they wanted to study how you can try to transform cellulose into a plastic. As the introduction explains:
    >But when heating pulp or paper, the common experience is that they rather reveal incineration than plastification

    These researchers observed a similar result when they just put cellulose to uniaxial pressure (i.e. pressing it on one axis, like in the video).


    1. Schroeter, J., et al. Melting Cellulose. *Cellulose* 2005: 12, pg 159-165. ([link](

  2. The paper burns? I assumed the grey coloring was from contacting the dirty pressing tools. Meaning I thought it was just metal imbedded in the paper.

  3. Is there a subreddit for vids like this? Crushing things in an hydraulic press? I’d watch the hell outta these vids

  4. Thank you! Ive seen the expolding paper videos on youtube so much but never found an explanation. Really cool, I wonder if people have done studies on paper under high pressure

  5. I accidentally did this as a kid! I was obsessed with the folding paper 7 times thing, so I would fold paper as much as possible and then roll it flat under stuff. I used hammers, put it behind car tires, and even a jewelers anvil. It always crumbled and was covered in black, so I wrote it off as me screwing the experiment up. Years later, imagine my surprise.

  6. Actually, you can fold it up to 11 times if I remember correctly. It was done in Mythbusters, they made the paper bigger so the paper was thinner.

  7. I managed to do that to a bit of paper by sandwiching it in between my calculator and it’s cover on the back for like a month.

  8. I tried using this, plus the whole “bend a paperclip a bunch and feel the heat”, arguments on /r/conspiracy to explain why massive internal ruptures during destruction of the WTC towers on 9/11 could cause some of the heat symptoms of steel deformation in the rubble. Got reported and downvoted into eternity. But it’s right there ^^^^.

Leave a Reply

Your email address will not be published. Required fields are marked *