Hello Kholqillah,

Through my experience, I think you'd better to make the solution with the concentration of silane depended on the weight of fiber. That is because the nature of the chemical treatment is through the reactions between the silane and the oxide functions (-OH or -COOH) on the surface of particles. I read a paper before which said the amount of silane should be no more than10% weight ratio of the particles when you do the chemical modification.

Regards,

Dahang

Kholqillah,

Here are some recent articles that might answer your concern.  I think type of natural fiber that you want to treat is also important. 

Regards,

Ali Amiri

http://www.sciencedirect.com/science/article/pii/S1359835X16000361

http://www.sciencedirect.com/science/article/pii/S0142941817300922

thank you for the answers