Vim yog cov pa roj carbon dub nqus tau cov dej noo, cov khoom sib xyaw dub PE rhiab heev rau cov dej noo. Lub sijhawm khaws cia ntev lossis qhov chaw khaws cia hnyav yuav ua rau cov dej noo ntau ntxiv. Raws li cov xwm txheej dav dav thiab cov ntawv thov, peb pom zoo kom ua ntej cua sov tsawg kawg 1 teev thiab qhov kub siab tshaj plaws ntawm 90 ° C.