Q. Is it better to use a taalis made of silk that is of an impure worm sheretz origin or better use rayon which originates from cellulose from permitted wood and plants?
Can you use Lanital artificial wool (created from milk) for tzitzis is that the same as synthetic or is it like cotton?
A. Shulchan Aruch (O.H. 9: 3), maintains that silk can be used for the taalis and the tzitzis. Although Magen Avraham (586: 3) asserts that the whole Torah is compared to Tefilin, on which the Torah demands that they should be made only from "what is permitted for your mouth," in reality it does not apply to all mitzvos, rather only to the ones that have inherent kedusha on them or a special mitzva holiness or sanctity like a shofar but not a taalis. (Ran - Rosh Hashana 28a, See Noda Beyehuda O.H. 2: 3 and others).
However, some Poskim are doubtful and opine that on the onset both tzitzis and taalis should be made from "what is permitted for your mouth" (Artzos Hachaim 9: 3, Kaf Hachaim ibid.).
Torah Lishma (4) quotes Rabbenu Bachya (Shemos 25: 3) that we do not find silk being donated for the Mishkan, as it originates from an impure animal. He adds that although there is a notable difference between the Mishkan and tzitzis, he recommends that on the onset one should choose a spiritual pure source material.
Igros Moshe (O.H. 2: 1) mentions rayon as an artificial material and following his opinion he does not allow it for a taalis or tzitzis, however as was mentioned in the question above, other Poskim disagree.
Horav Shlomo Miller's Shlit'a opinion is as mentioned in the prior question that clothing made from synthetic threads is liable for tzitzis and one can recite a brocho on them.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a
Important Numbers
