Cov kab hmoov txheej yog dab tsi?

Cov kab hmoov txheej yog dab tsi? Cov hmoov txheej txheej yog tsim los siv cov txheej txheem tiv thaiv thiab kho kom zoo nkauj polymer txheej rau ntau yam khoom siv hlau, nrog rau cov rooj tog zaum, cov khoom siv hauv tsev, cov khoom siv hauv tsheb thiab kev ua liaj ua teb, cov qhov rooj armored, cov khoom lag luam, cov khoom siv vaj tsev vaj tsev, thiab lwm yam.