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Topic: Collagen for musical strings  (Read 401 times)

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Offline Enthalpy

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Collagen for musical strings
« on: February 19, 2019, 11:08:16 AM »
Hello dear friends!

The best musical strings are still made from gut, possibly spun with metal wire. Gut is often replaced with PA11 polyamide or with metal, but nothing provides the crispy, profound and long sound of gut, for reasons not fully understood. Strength per mass unit is mandatory, very low mechanical losses too, density and bendability are useful, and I believe elastic strain matters.

"Catgut" is one sheath of the lower part of the intestine of sheep, sometimes goats or cows, after mechanical and chemical processing which I understand leave only the collagen, in fibres oriented essentially lengthwise
https://www.gamutmusic.com/new-page
http://web.mit.edu/3.082/www/team1_f02/collagen.htm

The upper part of the intestine made sausage casings, but for decades collagen widely replaces it because the process is simpler
https://en.wikipedia.org/wiki/Collagen#Uses

Similarly, it would be nice to make musical strings of collagen, where at some process step collagen would be a homogeneous melt or solution, to obtain more easily strings of repeatable properties. The cited Wiki paragraph, brief and not quite clear about it, mentions:
"It is widely used in the form of collagen casings for sausages, which are also used in the manufacture of musical strings."
but I've never heard about a musical string made of collagen, far less a good string, so there must be hurdles.

What are your thoughts, please?

Do you imagine sausage casings are just molten natural collagen extruded in tube shape?

How difficult would it be to orient the macromolecules of collagen? PA11 achieves thick monofilament strings of good strength, but if this is impossible with collagen, string makers can assemble fibres into a string. To my understanding, very thin extrusion or stretching is what makes ultra-strong Dyneema fibres and ropes from banal polyethylene.

Thank you!

Offline Enthalpy

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Re: Collagen for musical strings
« Reply #1 on: February 20, 2019, 03:17:35 PM »
Yarn from collagen exists already and serves for medicine. Citing subchap 2.4 of:
   Biomaterials Science: An Introduction to Materials in Medicine
   By Allan S. Hoffman, Frederick J. Schoen, Jack E. Lemons
"Reconstituted collagen is obtained by enzymatic chemical treatment of skin or tendon followed by reconstitution into fibrils. These fibrils can then be spun into fibres..."

Gut is a raw material long enough for strings, but to spin fibres, tendon seems an interesting alternative. Or continue with gut if the strings are better.

Wiki suggests that the exact spinning method is paramount to stretch and orient the macromolecules and transform weak polyethylene into ultra-strong Dyneema and Spectra
https://en.wikipedia.org/wiki/Ultra-high-molecular-weight_polyethylene#Fiber
https://en.wikipedia.org/wiki/Spinning_(polymers)#Gel_spinning
it seems logical: the lower exit temperature in gel spinning keeps the order acquired by the macromolecules in the spinneret.

Whether this achieves strings as good as gut?

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