Dangantakar Tsarin Tsarin PTFE

Hanya don fahimtar tasirin fluorine shine bincika bambance-bambance tsakanin polyethylene na layi (PE) da PTFE wanda shine madaidaicin fluoropolymer dangane da kaddarorin da halaye.

Akwai mahimman bambance-bambance tsakanin kaddarorin PE da na PTFE:

• * PTFE yana ɗaya daga cikin mafi ƙasƙanci na makamashin polymers
• *PTFE shine mafi yawan juriya na sinadarai
• *PTFE yana ɗaya daga cikin mafi yawan ƙarfin ƙarfin polymers
• *Matsayin narkewa da takamaiman nauyi na PTFE sun ninka na polyethylene

Bambance-bambancen PTFE da PE ana iya danganta su ga bambance-bambancen shaidun CeF da CeH.Bambance-bambance a cikin kayan lantarki da girman F da H suna haifar da abubuwan lura masu zuwa:

• *F shine mafi yawan electronegative na dukkan abubuwa (4 Paulings)
• *F yana da nau'i-nau'i na lantarki marasa rabawa
• *F yana da sauƙin juyawa zuwa Fe
• *Ƙarfin haɗin gwiwa na CeF ya fi CeH
• *F ya fi H girma

Electronegativity na carbon a 2.5 Paulings ya ɗan fi na hydrogen kuma ƙasa da electronegativity na fluorine.Sakamakon haka, madaidaicin haɗin CeF ya saba wa na CeH bond, kuma haɗin CeF ya fi karkata sosai.A cikin haɗin CeF, ana cajin ƙarshen haɗin fluorine mara kyau idan aka kwatanta da haɗin CeH wanda a cikinsa ake cajin carbon mara kyau.

Bambanci a polarity na CeH da CeF yana shafar kwanciyar hankali na daidaitattun sarƙoƙin polymer guda biyu.Crystallization na polyethylene yana faruwa a cikin tsarin tsari da canzawa.Ana iya tilasta PTFE cikin irin wannan jujjuyawar tare da matsanancin matsin lamba.PTFE, ƙasa da 19 C, yayi crystallizes azaman helix tare da 0.169 nm a kowane maimaita nisa: yana ɗaukar atom 13 C don juyawa 180 don kammala.Sama da 19 C, nisan maimaitawa yana ƙaruwa zuwa 0.195 nm wanda ke nufin ana buƙatar atom ɗin carbon 15 don juyawa 180.A sama da 19 C sarƙoƙi suna da ikon juyawa na kusurwa, wanda ke ƙaruwa sama da 30 C har zuwa lokacin narkewa (327 C).

Sauya F don H a cikin haɗin CeH yana haɓaka ƙarfin haɗin gwiwa daga 99.5 kcal/mole don haɗin CeH zuwa 116 kcal/mole don haɗin CeF.Sakamakon haka, kwanciyar hankali na thermal da juriya na sinadarai na PTFE ya fi PE girma saboda ana buƙatar ƙarin kuzari don karya haɗin CeF.Ƙarfin haɗin gwiwa da ƙarfin haɗin gwiwar CeF yana ba da injin abstraction F atom don reshe mai wahala.Sabanin haka, ana iya haɗa polyethylene mai rassa sosai (> 8 rassa a cikin 100 carbon atom).Tsarin reshe azaman kayan aiki don daidaita crystallinity ba aiki bane ga PTFE.A maimakon haka, masu haɗin gwiwa tare da ƙungiyoyin da aka lanƙwasa dole ne a yi musu polymerized tare da TFE.

Crystallinity na PTFE da ba a taɓa narkewa ba yana cikin kewayon 92e98%, daidai da tsarin sarkar da ba a haɗa shi ba.FEP, wani copolymer na TFE da HFP, yana da as-polymerized crystallinity na 40e50%.A cikin FEP, ƙungiyar CF3 mai raɗaɗi tana haɗe da carbon na uku wanda ba shi da kwanciyar hankali fiye da na farko da na biyu na carbon atom.Ƙimar ƙazantawa suna nuna raguwar yanayin zafi na 300 C don FEP (0.02% asarar nauyi) da 425 C don PTFE (0.03% asarar nauyi).