Isifundo Sokuguqulwa kwe-EVA

I-ethylene-vinyl acetate copolymer, efushaniswe ngokuthi i-EVA, iyipulasitiki eyakhiwe ngama-non-polarity, ama-crystalline vinyl monomers kanye nama-non-crystalline vinyl acetate (VA) monomers. Ukuguquguquka, ukuqina, ukumelana nokuqhekeka kokucindezeleka, ukucaca, kanye nokuhambisana nama-filler kungcono kune-polyethylene (PE). I-EVA ingenziwa ibe imikhiqizo ehlukahlukene ngezinqubo zokubumba ezifana nokukhipha.

Ngobuchwepheshe bokuguqula ingxube, ukusebenza kwe-EVA kungathuthukiswa ngempumelelo, futhi ububanzi kanye nokuzivumelanisa nezimo kokusetshenziswa kwayo kungandiswa. Ukuze wonke umuntu aqonde ukuxuba nokuguqula i-EVA, uXiaobian uqoqe izinto ezifanele ukuze wonke umuntu azifunde.

Izici ezithonya ukusebenza kwe-EVA.

01. Umphumela Wokuqukethwe kwe-VA Ekusebenzeni kwe-EVA

Umthelela wokuqukethwe kwe-VA ekusebenzeni kwe-EVA ubonakala kakhulu ezicini ezimbili.

① Amaqembu aseceleni e-Va abhubhisa isifunda sekristalu esakhiwe yisigaba se-polyethylene chain, ngokwanda kokuqukethwe kwe-VA, ubukristalu be-EVA buyancipha kancane kancane, lapho okuqukethwe kwe-VA kuqhubeka nokwanda kufika ku-40% kuya ku-50%, i-EVA copolymer iba isakhiwo esingahleliwe ngokuphelele;

② Njengoba i-VA iyiqembu eliyi-polar, ngokwanda kokuqukethwe kwe-VA, i-polarity ye-EVA iba nkulu, kangangokuthi izici zayo eziningi zishintshile, njengamandla okudonseka, ukumelana nokuguquguquka kokushisa, ukumelana nokugqwala kwamakhemikhali nezinye izakhiwo zehlile, kuyilapho i-permeability friction coefficient, ukumelana nokuqhekeka kokucindezeleka kwemvelo kanye nezinye izakhiwo zithuthukile.

02. Umphumela Wokusatshalaliswa Kwesisindo Sama-Molecular Ekusebenzeni Kwe-EVA

I-EVA enokusatshalaliswa kwesisindo sama-molecule okubanzi, amaketanga amade kulula ukuwahlanganisa kunemaketanga amafushane, futhi ama-molecule amaketanga amade angamunca iningi lamandla okuguqulwa futhi abonise impendulo ephezulu yokunwebeka, ngakho-ke i-EVA enokusatshalaliswa kwesisindo sama-molecule okubanzi inokubonakala okukhulu uma ibhekene nesenzo esincane sokucheba, okungelula ukugeleza, kodwa okulula ukugeleza. Ekucutshungulweni nasekukhiqizweni kwangempela, lobu budlelwano be-viscosity/shear ngenxa yokusatshalaliswa kwesisindo sama-molecule okuhlukene buzoba nomthelela othile ekukhethweni kwezinto zokusetshenziswa ze-EVA.

Ngaphezu kwalokho, lapho isisindo sama-molecule se-EVA sanda, amandla okushisela okushisa, ukuncibilika okuncibilikayo, ukuphambuka, ukuqina, ukumelana nokuqhekeka kokucindezeleka nokunye kwe-EVA kuyathuthuka.

03. Iqiniso Lokuhlukaniswa Kwezinga Le-Molecular Chains Ekusebenzeni Kwe-EVA

Uma kuqhathaniswa nama-molecule e-EVA kanye ne-PE, i-EVA iphazamisa isimo sokuqala sokukristala ngenxa yokwethulwa kwamagatsha amafushane akhiwe ngamaqembu e-polar kumaketanga amagatsha ama-molecule, ukuze i-EVA ithambekele "ekukhiqizeni ipulasitiki", yandise ibanga phakathi kwamaketanga ama-molecule e-polymer, ngaleyo ndlela inciphise ukukristala kwe-polymer, okwenza i-EVA ithambe futhi inwebeke kakhulu kune-PE; isithiyo sendawo sokwakheka kweqembu le-CH3COO kuketanga lama-molecule e-EVA senza ukukristala kanye nokushisa kwengilazi kuhluke kokwe-polyethylene ephansi (LDPE). Ukuzinza kokushisa, ukuguga kanye nezinye izakhiwo zomzimba nezemishini ze-EVA nazo ziyathinteka.

Indlela Yokuguqula ye-EVA

01. Ukugcwalisa Kushintshiwe

Ukugcwalisa kuyindlela elula nephumelelayo yokuguqula i-polymer, engakwazi nje ukugcina izinzuzo ze-polymer ngokwayo, kodwa futhi isebenzise umphumela wokuhlanganisa ukuthuthukisa amaphutha, ukufeza umgomo wokuthuthukisa ukusebenza okuphelele kwe-polymer. Njengamanje, ukuguqulwa kokugcwalisa kwe-EVA kunendlela yobuchwepheshe bokuguqula ubuso be-nano-functionalization kanye nokugcwalisa.

① Ukugcwalisa i-EVA ngamatshe e-hydrotal (LDHs) kungathuthukisa amandla okugoba kwe-EVA.

②Ukugcwalisa i-EVA nge-magnesium hydroxide (Mg(OH)2) kungathuthukisa ukuzinza kokushisa kwe-EVA, kuthuthukise amandla okunamathela kanye nokugeleza kokucubungula.

③ Ukuguqulwa kwe-EVA hot melt adhesive ngezinhlayiya ze-ferric oxide (Fe3O4) kungathuthukisa ukunamathela kwe-hot melt adhesive futhi kuthuthukise ukugeleza kwayo kokuncibilika ngaphakathi kobubanzi obuthile.

④ I-NANO-SiO2 enengxenye yokugcwalisa eyi-volumetric engu-4% ingakhulisa amandla okudonseka kwezinto ezihlanganisiwe ze-EVA/SiO2.

Izinhlobo zezigcwalisi ezisetshenziswa ekuguqulweni kwezigcwalisi ze-EVA ziyanda kakhulu, kodwa kusenezinkinga eziningi ekuguqulweni kwezigcwalisi, indlela yokuthuthukisa ukusabalala kwezigcwalisi ku-matrix ye-EVA, njll. Ukuxazululwa kwalezi zinkinga kusiza ekuthuthukiseni ukusebenza kwe-EVA.

02. Ukuguqulwa Kokuxuba

Ukuhlanganisa nokuguqula i-EVA kungathuthukisa ukuhlanganiswa kwezakhiwo zama-polymer ahlukene, ukuze i-EVA ikwazi ukuthola izakhiwo ezintsha futhi ithuthukise ukusebenza kwesici esithile. Ukuhlanganisa i-EVA namanye ama-polymer anokuhambisana okuhle kuyisici esibalulekile socwaningo lokuguqulwa kwe-EVA eminyakeni yamuva.

① Uma i-15% EVA-g-MAH ingezwa ohlelweni lokuxuba lwe-EVA/halogen-free flame retardant copoly polyester (P-PET), ukuhambisana kwayo, ukugeleza kwenqubo kanye nokuncipha komlilo kungathuthukiswa.

② Kuhlelo lokuxuba lwe-EVA/high-density polyethylene (HDPE), lapho okuqukethwe kwe-HDPE kungu-15%, izakhiwo zomshini zokuphotha kanye nemicu exubile yizona ezingcono kakhulu.

③ Kuhlelo lokuxuba lwe-EVA/NBR, izinga lokushisa eliphakeme kakhulu lokubola kokushisa lingatholakala ngokungeza i-oxidized diisobenzotride (DCP).

Ngokuthuthuka kwesizukulwane sesithathu sobuchwepheshe be-polymer alloy, njengobuchwepheshe benethiwekhi ye-polymer engene ngaphakathi, ubuchwepheshe be-dynamic vulcanization,ubuchwepheshe bokukhipha ukusabela, ubuchwepheshe obuhlanganisiwe bama-molecule, njll., ukusebenza okungcono nangcono kakhulu kwezinto zokuxuba i-EVA kuzothuthukiswa ukuze kuhlangatshezwane nezidingo zobuchwepheshe obuhlukahlukene bobunjiniyela bezinto zokwakha.

03. Ezinye Izinguquko

Ngaphezu kocwaningo lwendabuko mayelana nokugcwalisa nokuguqula ukuxuba kwe-EVA, kube nenqubekela phambili enkulu yocwaningo ekuhlanganisweni kwamakhemikhali kanye nokuxhumanisa i-EVA eminyakeni yamuva nje, okubeke isisekelo esihle sokuthuthukiswa kwezinhlobo eziningi zemikhiqizo ye-EVA.

① I-Benzoyl peroxide (BPO) isetshenziswa njenge-ejenti yokuxhumanisa ukuze kuthuthukiswe izinga lokubuyiselwa kwesimo sento.

② I-polymer ye-EVA-g-PU itholakale ngendlela yokuxubha encibilikisayo, eyathola amandla okudonsa nokunwebeka okungcono lapho iphuka kunezinto zokusetshenziswa. Futhi ukwengezwa kwama-prepolymer e-PU nakho kungathuthukisa ngempumelelo ukusebenza kokuqina kokushisa kwe-EVA.