Dear Balsam mahmood Shaker, it depends on the properties you want to reach. Please have a look at the following documents. My Regards

https://doi.org/10.1016/j.procs.2019.05.003

https://doi.org/10.1016/j.compositesb.2016.06.051

Thank you professor Abdelkader BOUAZIZ

No thanks, though you didn't added more details, I extend a little bit my previous answer. If mechanical properties such as resistence in tension, fibers are more suitable, however if friction/abrasion is you goal, powdered reinforcing filler is to be used. Best of success in your work

Hi Dr Balsam mahmood Shaker . I hope the following link might help:Article Natural fiber-mediated epoxy composites – A review

Also, see the following link; Article Tough, natural-fibre composites based upon epoxy matrices

Kindly, see the following link too: Article Recent advances in epoxy resin, natural fiber-reinforced epo...

This answer helped a lot.. I just started the idea of the work.. I appreciate you time thank you professor Abdelkader BOUAZIZ

Thank you professor Aref Wazwaz

You are most welcome dear

Dr Balsam mahmood Shaker .

Wish you the bes always.

Hello Balsam mahmood Shaker,It depends on type of natural fiber that you are utilizing where its aspect ratio play predominating role over the matrix and also properties you are looking for in the developed composite.

Fabrics are best.

It depends on the product you want to use if you need an isotropic material (same property in all directions) then use the chopped fibers, if you need an anisotropic property such as in rods or cap then use the whole fiber. you can use it unidirectional or 0/90 direction or 0/+45/-45/0

Respected Sir,

http://dx.doi.org/10.1155/2021/6078155

http://dx.doi.org/10.1002/pc.26326

hope this would be helpful!