As far as I know, regular paper has certain orientation, MD and CD. Fibers in paper normally have a preferred orientation. I want to know what kind of paper are completely randomly oriented. How about Whatman filter paper? Thanks.
To my knowledge, the fibers of most papers are quite randomly oriented in the early stages of the process within the plane of the paper. I doubt there is any paper with three dimensional random fibers. The Yankee drum portion of the process in the final drying and pressing stages of making many papers, in particular absorbent materials such as paper towels and toilet paper, leaves a residual stress in the paper and orients the fibers. You can observe this by placing a few water drops on the paper and observing that the wrinkles that form have a preferential orientation.
Scott paper company developed and patented an alternative press that does not leave this residual stress. The water test confirms that there is no consistent pattern in the wrinkles in their paper towels. Papers produced by them and their licensees should have random fiber orientation, at least within the plane of the paper.
I am not sure about Whatman filter paper, but the water test might reveal any residual stress that may be associated with fiber orientation.
Hi Larry,
Thanks very much for your answer. I don't need it to be completely random in three dimensional. My hope is to find paper samples with fibers as random as possible in the plane. Besides, we plan to do some tensile tests, so good strength is very necessary. I guess tissue and paper towel is too weak for us.
Most papers go through a Yankee drum that gives them some orientation and residual stress (except Scott paper). The water test is easy and obvious with paper towel and tissue, but the same thing should happen with nearly all paper.
Cellulosic fibres (all type of fibres: softwood, hardwood, annual plants, etc.) within the papermaking process “build” a matrix and retain the filler (with the help of the retention agent and the sizing system). So, the fibres have a random orientation in all the paper grades. The links between the fibres are stronger or weaker depending on the paper grade, final utilization, additives used within the papermaking process, filler quantity and type, etc.
I think your expectations fulfil a hand-paper prepared by use of hand-sheet testing laboratory device.
All industrial papers manufactured with Fourdrinier paper machine or also vat type machine are oriented preferentially in the so called "machine direction" (MD) which is the direction of manufacture of the web. In general is very difficult to found what the papermakers say a perfect square paper.
As one of the previous colleagues says the best way to have a random orientation is the manufacture of hand sheet papers with a laboratory former. In this case there is no preferential orientation
You may find the article mentioned below useful. Happy new year.
https://www.researchgate.net/publication/315427845_Agricultural_Residues_Wastes_for_Manufacture_of_Paper_Board_and_Miscellaneous_Products_Background_Overview_and_Future_Prospects?_sg=Uu4mwgriwm6wL8ftXpL5UBggMxWBfZLdnE0gR8lNMmTh-fK3gfLEn3bLwrRvsJcAflz1lFUgYF30K-ofvYbpbm0KzDdY0Y-a2v4SLHPD.4stRPO63yIkvIMx1DqCKN-VDQWWyFJkAWRRxRWsUAghOhpup7jYjgG47ZJMXFPGLz3oc9aW6B9i_LZw6DXHkMg