Ta yaya cikar yake shafar halayen lu'ulu'u na polymer?

Gano kyawawan halaye na haɗakar nailan 6/laka a shekarun 1980 ya haifar da bincike mai yawa kan haɗakar polymer da aka cika da kuma sake fahimtar rawar da masu cikawa ke takawa a cikin polymers. Ga yadda masu cikawa ke tasiri kan halayen haɗakar polymers.

Tasirin abubuwan cikawa akan yanayin lu'ulu'u na polymers

Ƙarin abubuwan cikawa yana shafar yanayin lu'ulu'u na polymer:

Polymers na lu'ulu'u suna samar da siffofi daban-daban na lu'ulu'u a ƙarƙashin yanayi daban-daban na lu'ulu'u, kuma lu'ulu'u masu siffar ƙwallo suna ɗaya daga cikin siffofin da aka fi sani na lu'ulu'u na lu'ulu'u. A ƙarƙashin yanayin gyare-gyare da sarrafawa na yau da kullun, polymers na lu'ulu'u galibi suna samar da siffofi na lu'ulu'u masu siffar ƙwallo.

Ƙara abubuwan cikawa yana taka rawa wajen haɓaka nucleation da kuma tace hatsi iri-iri:

Manyan lu'ulu'u masu siffar ƙwallo da ƙananansu suna zama ƙanana da ƙanana, kuma gyaran lu'ulu'u masu siffar ƙwallo da kuma inganta ƙarfin kayan abu suna da amfani kuma suna iya zama hanya mai tasiri don ƙarfafa polymers.

Dacewar filler tare da matrix na resin shima yana da tasiri akan yanayin kristal:

Misali, Qiao Fang da abokan aikinsa sun gano cewa montmorillonite mai tsari yana lalata tsarin lu'ulu'u mai siffar zobe na nailan 6, galibi saboda kwayoyin nailan 6 suna da tasirin haɗin gwiwa mai ƙarfi tare da ƙwayoyin montmorillonite masu tsari, don haka motsi na sassan sarkar kwayoyin nailan 6 yana da cikas a cikin tsarin lu'ulu'u, kuma yana da wuya a girma cikin tsari mai daidaituwa da na yau da kullun tare da alkiblar radial, don haka tsarin girma lu'ulu'u yana da cikas, don haka yana haifar da lu'ulu'u marasa cikas.

A lokacin tsarin ƙera kayan haɗin polymer masu cike da fibrous, zaruruwan na iya taka rawar nucleation kuma lu'ulu'u masu siffar ƙwallo ba su da yanayin girma mai girma uku yayin tsarin girma, wanda daga nan zai ɗauki siffar girma mai siffar ƙwallo, watau, girma mai girma ɗaya wanda ke samar da lu'ulu'u masu juyawa.

Misalai:

Sinadaran Nucleating wani nau'in abubuwa ne da za su iya canza halayen lu'ulu'u na resins da kuma canza yanayin ƙwayoyin polymers don ba su sabbin halaye da ayyuka, kuma batu ne da ake tattaunawa a yanzu a gida da waje.

Tsarin aiki: A yanayin narkewa, yayin da wakilin nucleating ke samar da ƙwayoyin da ake buƙata, polymer yana canzawa daga nucleation iri ɗaya zuwa nucleation iri-iri, wanda ke hanzarta ƙimar lu'ulu'u kuma yana inganta tsarin hatsi, kuma yana inganta tauri na samfurin.

Ana iya raba sinadaran nucleating zuwa ga sinadaran nucleating marasa tsari, sinadaran nucleating na halitta da kuma sinadaran nucleating na polymer. Sinadaran nucleating na Nanoparticle sun zama wuri mai zafi don binciken sinadaran nucleating saboda yawancin cibiyoyinsu masu aiki a saman, waɗanda za a iya haɗa su da substrate kuma suna da daidaito mafi kyau, kuma ƙwayoyin ba sa rabuwa cikin sauƙi idan aka fuskanci ƙarfin waje.

Tasirin abubuwan cikawa akan kinetics na polymer crystallization

Tsarin lu'ulu'u na polymer ya ƙunshi matakai biyu: nucleation da girma. Yawanci ana amfani da lissafin Avrami don bayyana tsarin lu'ulu'u na isothermal na polymers, kuma ta hanyar gano ma'aunin Avrami n da kuma daidaitaccen ƙimar lu'ulu'u K, ana iya samun tsarin girma na lu'ulu'u da ƙimar girma.

Mucha M da abokan aikinsa a cikin bincikensu kan kinetics na crystallization na carbon black filling PP sun gano cewa akwai wani abu mai matakai biyu na crystallization: a farkon matakin crystallization da ya shafi nau'ikan nucleation daban-daban na PP, nucleation a saman barbashi masu launin carbon, babu wani karo na nuclei da ya faru a farkon matakin crystallization kuma girma bai iyakance ba; sai kuma a hankali matakin crystallization inda aka rage saurin girma ta hanyar karo tsakanin lu'ulu'u. A farkon matakin crystallization, n ya kasance kusan 2.0, yayin da a matakin ƙarshe na crystallization, n ya kasance kusan 3.0. An kuma gano cewa ƙarin adadin carbon black daban-daban yana da tasiri daban-daban akan ƙimar K da n. A daidai wannan zafin crystallization, ƙimar K ta ƙaru tare da ƙaruwar ƙarin carbon black.

A bisa ga lissafin Avrami, ƙimar n ya kamata ta zama lamba mai kyau ƙasa da 4 ko daidai da ita. A aikace, ƙimar n na tsarin lu'ulu'u na polymers yawanci lamba ce mai lamba goma kuma tana kama da 5, wanda ke nuna cewa ainihin tsarin lu'ulu'u ya karkace daga lissafin Avrami kuma abin da ke faruwa na lu'ulu'u na biyu ko karo na lu'ulu'u mai siffar ƙwallo yana faruwa.

Tsarin tsarin lu'ulu'u na polymers masu cike da lu'ulu'u

A cikin 'yan shekarun nan, ka'ida da gwaje-gwaje sun nuna sarai cewa akwai yankin canji tsakanin yankunan lu'ulu'u da kuma yankunan da ba su da tsari na lu'ulu'u. polymers, watau, wani yanki mai tsaka-tsaki, wanda ake kira lu'ulu'u - matakin tsaka-tsaki mara tsari.

An yi nazarin tasirin talc akan tsarin yankin crystalline, yankin amorphous da matsakaicin matakin polyethylene mai ƙarancin yawa (LDPE) ta hanyar amfani da na'urar hangen nesa ta infrared mai girma biyu. Sakamakon ya nuna cewa ƙara talc yana yin wasu canje-canje a cikin tsarin crystalline na LDPE, kuma an kammala da cewa talc yana da alaƙa da yankin crystalline amma ba tare da yanayin amorphous ba, wanda ke haifar da tsarin tsarin da aka ƙaddara.

Nazarin tasirin abubuwan cikawa akan halayen lu'ulu'u na polymers na iya haifar da fahimtar tsarin lu'ulu'u da kuma tsarin lu'ulu'u na polymers na kristal. Bugu da ƙari, halayen lu'ulu'u na polymers da aka cika na iya shafar halayen abubuwan haɗin kai tsaye, don haka ya kamata a kula da wannan.

Duk da cewa an sami ɗan ci gaba a nazarin tasirin abubuwan cikawa akan halayen lu'ulu'u na polymers, har yanzu akwai ƙarancin bincike mai zurfi, tsari da cikakken bayani, kuma idan za a iya tsara wannan ɓangaren, ya kamata ya haifar da babban matakin bincike a cikin shirye-shiryen kayan aiki da kaddarorin.