Are Chemical Treatments Essential in Handmade Papermaking?

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Discussion Overview

The discussion revolves around the necessity of chemical treatments in the handmade papermaking process, specifically whether such treatments are essential for converting raw plant materials into pulp or if mechanical processes suffice. The conversation explores the implications of lignin presence in paper and the effects of various treatments on the final product.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants question whether chemical treatments like boiling in soda ash are necessary for pulping, suggesting that mechanical processes may be sufficient.
  • One participant notes that while mechanical pulping is essential, chemical delignification may not be required if the goal is to produce paper that will yellow over time.
  • Another participant mentions that reduced washing can exacerbate yellowing and degradation of paper, highlighting the importance of acid-free paper for preservation.
  • It is proposed that lignin can remain in mechanically pulped paper, and alternative chemical treatments can be used to remove color-causing molecules without dissolving cellulose or lignin.
  • A participant shares personal experience with making paper from amaranthus, noting the stickiness of the pulp and questioning whether the soda ash treatment effectively accomplishes delignification or merely removes impurities.
  • Concerns are raised about the role of sodium carbonate in increasing pH and its effects on dye uptake, with uncertainty about its impact on lignin dissolution.

Areas of Agreement / Disagreement

Participants express differing views on the necessity and role of chemical treatments in handmade papermaking, indicating that multiple competing perspectives remain without a clear consensus.

Contextual Notes

Participants highlight uncertainties regarding the definitions of "impurities" and the specific effects of chemical treatments on lignin and cellulose, indicating a lack of clarity in the processes involved.

Stephen Tashi
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In handmade papermaking, are the chemical treatments ( e.g. boiling in soda ash, soaking bamboo in lime juice) necessarily for turning raw plant material into pulp? Or is the creation of the pulp just a mechanical process of breaking up the material with a "hollander beater" or some other machine?

For example, the current Wikipedia article on lignin says that the paper used in making newsprint contains most of the original lignin in the plants. Does this imply that chemical treatments to dissolve lignin aren't needed to create pulp, if one is satisfied with producing paper that will yellow?
 
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FWIW - yellowing and paper falling apart with age are made worse by reduced washing. Hence more residual acid in the paper. This is why acid free paper is a must for musuem quality work, and why restorers may attempt to remove acid from older valuable documents.
 
Stephen Tashi said:
Does this imply that chemical treatments to dissolve lignin aren't needed to create pulp, if one is satisfied with producing paper that will yellow?

That's right, mechanical pulping is necessary for papermaking, but chemical delignification isn't always necessary for bleaching or brightening the paper. The lignin can be left in the mechanically pulped batch, then chromophores or color-causing molecules can be removed from the lignin with a different chemical treatment (doesn't dissolve the cellulose or lignin), which is more cost-effective as chemical delignification removes more bulk product. Also, some plants like Hemp have little lignin, so no chemicals are needed to make Hemp paper and it doesn't yellow.
 
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The craft-oriented descriptions of making paper by hand say (for many common plants) to boil the plants in soda ash to "remove impurities". It isn't clear to me if this accomplishes delignification or whether "impurities" refers to something else.

I tried making paper with some amaranthus ("pig weed") that grows in my yard. It was boiled in soda ash and pulped in a blender. The pulp is slightly sticky - unlike pulp I've made from copier paper. It makes a reasonable sheet of paper, but it tends to glue itself to any surface it is drying upon.
 
Stephen Tashi said:
The craft-oriented descriptions of making paper by hand say (for many common plants) to boil the plants in soda ash to "remove impurities". It isn't clear to me if this accomplishes delignification or whether "impurities" refers to something else.

I tried making paper with some amaranthus ("pig weed") that grows in my yard. It was boiled in soda ash and pulped in a blender. The pulp is slightly sticky - unlike pulp I've made from copier paper. It makes a reasonable sheet of paper, but it tends to glue itself to any surface it is drying upon.

It looks to me as if the sodium carbonate is used to increase the pH in order for the dye to take (probably removing waxes or hydrophobic impurities). It isn't breaking the cellulose down, and chemicals that break down lignin also break down cellulose, so, I'm not sure if it is dissolving the lignin.