nkhani

Kodi polyolefin ndi chiyani?

Polyolefins ndi banja la polyethylene ndi polypropylene thermoplastics.Amapangidwa makamaka kuchokera kumafuta ndi gasi wachilengedwe ndi njira ya polymerization ya ethylene ndi propylene motsatana.Kusinthasintha kwawo kwawapanga kukhala amodzi mwa mapulasitiki otchuka omwe amagwiritsidwa ntchito masiku ano.

Makhalidwe a polyolefins

Pali mitundu inayi ya polyolefins:

• LDPE (polyethylene yotsika kwambiri): LDPE imatanthauzidwa ndi kuchuluka kwa 0.910-0.940 g/cm3.Imatha kupirira kutentha kwa 80 °C mosalekeza ndi 95 °C kwakanthawi kochepa.Zopangidwa mosiyanasiyana kapena zowoneka bwino, zimakhala zosinthika komanso zolimba.
• LLDPE (linear low-density polyethylene): ndi polyethylene yozungulira kwambiri, yokhala ndi nthambi zazifupi zambiri, zomwe zimapangidwa ndi copolymerization ya ethylene yokhala ndi ma olefin aatali.LLDPE ili ndi mphamvu zolimbikira kwambiri komanso kukhudzika kwambiri komanso kukana nkhonya kuposa LDPE.Imasinthasintha kwambiri komanso imakulitsa kupsinjika.Itha kugwiritsidwa ntchito popanga mafilimu owonda kwambiri ndipo imakhala yolimbana bwino ndi mankhwala.Ili ndi mphamvu zamagetsi zamagetsi.Komabe, sikophweka kukonza ngati LDPE.
• HDPE (high-density polyethylene): HDPE imadziwika ndi chiŵerengero chachikulu cha mphamvu ndi kachulukidwe.Kuchulukana kwa HDPE kumatha kuchoka pa 0.93 mpaka 0.97 g/cm3 kapena 970 kg/m3.Ngakhale kachulukidwe wa HDPE ndi wokwera pang'ono kuposa wa polyethylene yotsika kwambiri, HDPE ili ndi nthambi yaying'ono, zomwe zimapatsa mphamvu zama intermolecular komanso mphamvu zolimba kuposa LDPE.Ndiwolimba komanso wosawoneka bwino ndipo imatha kupirira kutentha pang'ono (120 ° C kwakanthawi kochepa).
• PP (polypropylene): Kuchulukana kwa PP kuli pakati pa 0.895 ndi 0.92 g/cm³.Choncho, PP ndiye pulasitiki yamtengo wapatali yomwe imakhala yotsika kwambiri.Poyerekeza ndi polyethylene (PE) ili ndi zida zapamwamba zamakina komanso kukana kwamafuta, koma kukana kwa mankhwala.PP nthawi zambiri imakhala yolimba komanso yosinthika, makamaka ikapangidwa ndi ethylene.

Kugwiritsa ntchito polyolefins

Makhalidwe apadera amitundu yosiyanasiyana ya ma polyolefin amadzikongoletsa kuzinthu zosiyanasiyana, monga:

• LDPE: filimu yotsamira, zikwama zonyamulira, filimu yaulimi, zokutira zamakatoni amkaka, zokutira chingwe chamagetsi, matumba olemera a mafakitale.
• LLDPE: filimu yotambasula, filimu yonyamula mafakitale, zotengera zokhala ndi mipanda yopyapyala, ndi matumba olemetsa, apakati ndi ang'onoang'ono.
• HDPE: mabokosi ndi mabokosi, mabotolo (zazakudya, zotsukira, zodzoladzola), zotengera zakudya, zoseweretsa, matanki a petulo, zokutira zamafakitale ndi filimu, mapaipi ndi zinthu zapakhomo.
• PP: zoyikamo chakudya, kuphatikiza yoghuti, mapoto a margarine, zokutira zotsekemera ndi zokhwasula-khwasula, zotengera zosagwira ntchito mu microwave, ulusi wa kapeti, mipando ya m’munda, zotengera zamankhwala ndi zida zamagetsi, katundu, zida zakukhitchini, ndi mapaipi.