1, Qhov sib txawv tseem ceeb ntawm LDPE (tsis tshua muaj ntom ntom polyethylene) thiab HDPE (siab ntom ntom polyethylene) nyob hauv lawv qhov ntom ntom, lub cev, siv, thiab lwm yam. , thaum qhov ceev ntawm HDPE nyob nruab nrab ntawm 0.940-0.976g / cm³. L...
Nyeem ntxiv