Ma'anar yanayin canjin gilashin
Gilashin-Transition Temperature (Tg) ， shine zafin jiki wanda polymer ya canza daga yanayin roba zuwa yanayin gilashi zuwa yanayi mai ƙarfi sosai ko daga na ƙarshe zuwa na farko. Shi ne mafi ƙarancin zafin jiki wanda sassan macromolecular na amorphous polymers zasu iya motsawa cikin yardar kaina. Yawancin lokaci Tg. Ya bambanta dangane da hanyar aunawa da yanayi.
Wannan alama ce mai mahimmanci na aikin polymers. Sama da wannan zafin jiki, polymer yana nuna elasticity; a ƙasa da wannan zafin jiki, polymer yana nuna brittleness. Dole ne a yi la'akari da shi lokacin da aka yi amfani da shi azaman robobi, roba, filaye na roba, da dai sauransu. Misali, canjin gilashin gilashin polyvinyl chloride shine 80 ° C. Koyaya, ba shine babban iyakar zafin aikin samfurin ba. Alal misali, zafin aiki na roba dole ne ya kasance a sama da zafin jiki na gilashin, in ba haka ba zai rasa babban ƙarfinsa.
Saboda nau'in polymer har yanzu yana kula da yanayinsa, emulsion kuma yana da zafin canjin gilashin, wanda ke nuna alamar taurin fim ɗin da aka kafa ta hanyar emulsion na polymer. A emulsion tare da babban gilashin canji zafin jiki yana da wani shafi tare da high tauri, high sheki, mai kyau tabo juriya, kuma ba sauki ga gurbata, da sauran inji Properties ne daidai da mafi alhẽri. Koyaya, yanayin canjin gilashin da ƙaramin zafinsa na samar da fim shima yana da girma, wanda ke kawo wasu matsaloli don amfani da ƙarancin zafi. Wannan sabani ne, kuma lokacin da emulsion na polymer ya kai ga wani zafin canjin gilashin, yawancin kaddarorinsa za su canza mahimmanci, don haka dole ne a sarrafa zafin canjin gilashin da ya dace. Dangane da batun turmi da aka gyara na polymer, mafi girman yanayin canjin gilashin, mafi girman ƙarfin matsawa na turmi da aka gyara. Ƙananan zafin canjin gilashin, mafi kyawun aikin ƙarancin zafin jiki na turmi da aka gyara.
Mafi ƙarancin fim ɗin ma'anar yanayin zafi
Mafi ƙarancin Fim ɗin Zazzabi yana da mahimmancimai nuna busasshen turmi gauraye
MFFT yana nufin ƙananan zafin jiki wanda ƙwayoyin polymer a cikin emulsion suna da isasshen motsi don haɓakawa da juna don samar da fim mai ci gaba. A kan aiwatar da polymer emulsion forming wani m shafi fim, da polymer barbashi dole ne samar da wani a hankali cushe tsari. Sabili da haka, ban da rarrabawar emulsion mai kyau, yanayin da aka tsara don ƙirƙirar fim mai ci gaba kuma ya haɗa da lalata ƙwayoyin polymer. Wato, lokacin da matsa lamba na ruwa na ruwa ya haifar da matsa lamba mai yawa tsakanin nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i)).
Lokacin da barbashi suka haɗu da juna, matsa lamba da aka haifar ta hanyar canzawar ruwa yana tilasta barbashin da za a matse su kuma su lalace don haɗawa da juna don samar da fim ɗin rufewa. Babu shakka, don emulsion tare da ingantattun wakilai masu wuyar gaske, yawancin ƙwayoyin polymer sune resin thermoplastic, ƙananan zafin jiki, mafi girma da taurin kuma da wuya zai zama nakasa, don haka akwai matsala na ƙananan zafin jiki na fim. Wato, ƙasa da wani zafin jiki, bayan ruwan da ke cikin emulsion ya ƙafe, ƙwayoyin polymer har yanzu suna cikin yanayi mai hankali kuma ba za a iya haɗa su ba. Saboda haka, da emulsion ba zai iya samar da wani m uniform shafi saboda evaporation na ruwa; kuma Sama da wannan ƙayyadaddun zafin jiki, lokacin da ruwa ya ƙafe, ƙwayoyin da ke cikin kowane ƙwayar polymer za su shiga, watsawa, lalata, da tarawa don samar da fim mai gudana mai gudana. Wannan ƙananan iyaka na zafin da za a iya samar da fim ana kiransa mafi ƙarancin yanayin zafin fim.
MMFT alama ce mai mahimmancipolymer emulsion, kuma yana da mahimmanci musamman don amfani da emulsion a lokacin ƙananan yanayin zafi. Ɗaukar matakan da suka dace na iya sanya emulsion na polymer ya sami mafi ƙarancin zafin jiki na fim wanda ya dace da bukatun amfani. Alal misali, ƙara mai filastik zuwa emulsion na iya yin laushi da polymer kuma ya rage ƙananan zafin jiki na fim na emulsion, ko daidaita ƙananan zafin jiki na fim. Higher polymer emulsions amfani da additives, da dai sauransu.
MFFT na LongouVAE mai sake rarrabuwar latex fodaGabaɗaya yana tsakanin 0 ° C da 10 ° C, mafi yawanci shine 5 ° C. A wannan yanayin, dapolymer fodayana gabatar da fim mai ci gaba. Akasin haka, a ƙarƙashin wannan zafin jiki, fim ɗin foda na polymer foda ba zai ci gaba ba kuma ya karye.Saboda haka, mafi ƙarancin zafin jiki na fim shine mai nuna alama wanda ke wakiltar zafin aikin ginin. Gabaɗaya magana, ƙananan ƙarancin zafin jiki na fim, mafi kyawun aiki.
Bambance-bambance tsakanin Tg da MFFT
1. Gilashin canjin yanayin zafi, yanayin zafi wanda abu ya yi laushi. Yawanci yana nufin yanayin zafin da amorphous polymers suka fara yin laushi. Ba wai kawai yana da alaƙa da tsarin tsarin polymer ba, har ma da nauyin kwayoyinsa.
2.Taushi
Dangane da ƙungiyoyin motsi daban-daban na polymers, yawancin kayan polymer yawanci suna iya kasancewa a cikin jihohi huɗu na zahiri (ko jihohin injiniyoyi): yanayin gilashi, yanayin viscoelastic, yanayin roba mai ƙarfi (jihar roba) da yanayin kwararar viscous. Canjin gilashin shine sauyawa tsakanin yanayin daɗaɗɗen ƙarfi da yanayin gilashi. Daga yanayin tsarin kwayoyin halitta, zafin canjin gilashin wani yanayi ne na annashuwa na ɓangaren amorphous na polymer daga yanayin daskararre zuwa yanayin narke, sabanin lokacin. Akwai zafi canjin lokaci yayin canji, don haka canjin lokaci ne na biyu (wanda ake kira canji na farko a cikin injiniyoyi masu ƙarfi na polymer). A ƙasa da yanayin canjin gilashin, polymer yana cikin yanayin gilashi, kuma sassan kwayoyin halitta da sassan ba za su iya motsawa ba. Ƙwayoyin halitta (ko ƙungiyoyi) waɗanda ke haɗa kwayoyin halitta ne kawai ke rawar jiki a ma'auninsu; yayin da ke cikin yanayin canjin gilashin, ko da yake sassan kwayoyin halitta Ba zai iya motsawa ba, amma sassan sassan sun fara motsawa, suna nuna manyan kaddarorin roba. Idan yanayin zafi ya sake karuwa, duk sarkar kwayoyin za su motsa kuma su nuna kaddarorin kwararar danko. Gilashin canjin zafin jiki (Tg) shine muhimmin kayan jiki na polymers amorphous.
Canjin canjin gilashi yana ɗaya daga cikin yanayin yanayin yanayin polymers. Ɗaukar zafin canjin gilashin a matsayin iyaka, polymers suna nuna kaddarorin jiki daban-daban: a ƙasa da zafin jiki na gilashin, kayan polymer shine filastik; sama da gilashin canjin zafin jiki, kayan polymer shine roba. Daga hangen aikace-aikacen aikin injiniya, babban iyaka na zafin amfani da gilashin canjin zafin jiki na filastik injiniyoyi shine ƙananan iyaka na amfani da roba ko elastomers.
Lokacin aikawa: Janairu-04-2024