Babban matsin lamba -ƙananan polyethylene (HP{1}}LDPE, wanda aka gajarta a matsayin LDPE) an haɓaka masana'antu fiye da shekaru 70, kodayake tare da ganowa da haɓaka abubuwan haɓakawa na olefin polymerization, iri-iri da fitowar polyethylene sun kasance babba. Koyaya, babban matsi{4} polyethylene har yanzu yana da matsayi mai mahimmanci. Ethylene an polymerized zuwa babban nauyin kwayoyin polyethylene ta hanyar radical free a ƙarƙashin babban zafin jiki da matsa lamba, wanda yana da halaye masu zuwa:
(1) A ethylene polymerization dauki tsari ne mai karfi exothermic tsari. The zafi na polymerization na ethylene ne game da 93.5kJ / mol (ko 3.3kJ / g), da kuma takamaiman zafi iya aiki na ethylene a 235MPa da 150 ~ 300 digiri ne 2.51 ~ 2.85J / (g · digiri). Idan zafi na dauki ba za a iya cire a cikin lokaci, duk lokacin da Polymerization na 1% ethylene zai ƙara yawan zafin jiki da 12 zuwa 13 digiri. Idan zafin jiki ya yi yawa, zai kuma haifar da ethylene zuwa rubewa.
(2) Ƙarƙashin matsa lamba, an matsa ethylene zuwa wani lokaci na iska tare da nauyin 0.5g/mL, wanda yayi kama da ruwa wanda ba za a iya matsawa ba. A wannan lokacin, nisa tsakanin kwayoyin ethylene yana raguwa sosai, ta haka yana kara yawan radicals da kwayoyin ethylene. Yiwuwar karo yana da girma, don haka halayen polymerization yana da saurin faruwa.
(3) Ayyukan gyare-gyare na kyauta na sarkar girma a babban zafin jiki yana da girma, kuma hanyar canja wurin sarkar yana da wuyar faruwa, kuma polymer ɗin da aka samu yana da tsarin layi mai layi tare da ƙarin sassan sassan. Yawancin lokaci kowane 1000 carbon sarkar atom ya ƙunshi 20-30 rassan, crystallinity ne 45% -65%, yawa ne 0.910-0.925g / ml, haske nauyi, m, low zafin jiki juriya da kuma tasiri juriya.