Come learn 2000+ kanji and 6000+ vocabulary words with WaniKani.
Fibers that have been changed from other materials are synthetic fibers. They aren't natural because they were something else once. Like plastic, or kittens.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
I use a synthetic fiber broom for sweeping.