Koyarwar Gyara ta EVA

Ethylene-vinyl acetate copolymer, wanda aka rage wa suna EVA, filastik ne da aka yi da monomers marasa polarity, crystalline vinyl monomers da monomers marasa crystalline vinyl acetate (VA). Sassaucin EVA, tauri, juriyar tsagewar damuwa, bayyana gaskiya, da kuma dacewa da abubuwan cikawa sun fi polyethylene (PE) kyau. Ana iya yin EVA zuwa samfura daban-daban ta hanyar tsarin ƙira kamar extrusion.

Ta hanyar fasahar gyaran gauraya, ana iya inganta aikin EVA yadda ya kamata, kuma za a iya faɗaɗa iyawar amfani da shi da kuma daidaitawarsa. Domin kowa ya fahimci haɗakar EVA da gyaranta, Xiaobian ta tattara kayan aiki masu dacewa don kowa ya karanta.

Abubuwan da ke tasiri ga aikin EVA.

01. Tasirin Abubuwan VA akan Ayyukan EVA

Tasirin abun ciki na VA akan aikin EVA galibi yana bayyana ne ta fuskoki biyu.

① Ƙungiyoyin gefe na Va suna lalata yankin lu'ulu'u da sashin sarkar polyethylene ya samar, tare da ƙaruwar abun ciki na VA, lu'ulu'u na EVA yana raguwa a hankali, lokacin da abun ciki na VA ya ci gaba da ƙaruwa zuwa 40% zuwa 50%, copolymer na EVA ya zama tsari gaba ɗaya bazuwar;

② Tunda VA rukuni ne na polar, tare da ƙaruwar abun ciki na VA, polarity na EVA ya zama mafi girma, don haka da yawa daga cikin kaddarorinsa sun canza, kamar ƙarfin tensile, juriyar nakasassu na zafi, juriyar lalata sinadarai da sauran halaye sun ragu, yayin da coefficient na gogayya mai shiga, juriyar fasawa na damuwa da muhalli da sauran halaye sun inganta.

02. Tasirin Rarraba Nauyin Kwayoyin Halitta akan Aikin EVA

EVA tare da rarraba nauyin kwayoyin halitta mai faɗi, dogayen sarƙoƙi suna da sauƙin haɗawa da juna fiye da gajerun sarƙoƙi, kuma dogayen sarƙoƙi na iya ɗaukar yawancin kuzarin nakasa kuma suna nuna mafi girman amsawar roba, don haka EVA tare da rarraba nauyin kwayoyin halitta mai faɗi yana da babban danko lokacin da aka yi masa ƙarancin aikin yankewa, wanda ba shi da sauƙin gudana, amma yana da sauƙin gudana. A cikin sarrafawa da samarwa na ainihi, wannan alaƙar danko/yanka saboda rarrabuwar nauyin kwayoyin halitta daban-daban zai yi tasiri ga zaɓin kayan albarkatun EVA.

Bugu da ƙari, lokacin da nauyin kwayoyin halitta na EVA ya ƙaru, ƙarfin walda na thermal, danko na narkewa, karkacewa, tauri, juriya ga karyewar damuwa da sauransu na EVA suna inganta.

03. Infact na Matsayin Rassa na Sarkokin Kwayoyin Halitta akan Aikin EVA

Idan aka kwatanta da ƙwayoyin EVA da PE, EVA tana wargaza yanayin kristal na asali saboda gabatar da gajerun rassan da suka ƙunshi ƙungiyoyin polar a cikin sarƙoƙin ƙwayoyin halitta masu reshe, don haka EVA tana da "tasirin filastik", tana ƙara tazara tsakanin sarƙoƙin ƙwayoyin polymer, ta haka rage lu'ulu'u na polymer, yana sa EVA ta yi laushi da laushi fiye da PE; toshewar sitaci na sararin samaniya na samuwar ƙungiyar CH3COO akan sarƙoƙin ƙwayoyin EVA yana sa lu'ulu'u da zafin gilashi ya bambanta da na polyethylene mai ƙarancin yawa (LDPE). Haka kuma yanayin kwanciyar hankali na zafi, tsufa da sauran halayen jiki da na inji na EVA suma suna shafar.

Hanyar Gyaran EVA

01. An Gyara Cika

Cikowa hanya ce mai sauƙi kuma mai tasiri ta gyaran polymer, wadda ba wai kawai za ta iya kiyaye fa'idodin polymer ɗin kanta ba, har ma za ta iya amfani da tasirin haɗakarwa don inganta lahani, don cimma burin inganta cikakken aikin polymer. A halin yanzu, gyaran cika EVA yana da yanayin zuwa fasahar nano-functionalization da gyaran saman filler.

① Cika EVA da duwatsun hydrotal (LDHs) na iya inganta ƙarfin lanƙwasa na EVA.

②Cika EVA da magnesium hydroxide (Mg(OH)2) na iya inganta yanayin zafi na EVA, inganta ƙarfin juriya da kuma sauƙin sarrafawa.

③ Gyaran manne mai zafi na EVA tare da barbashi na ferric oxide (Fe3O4) na iya inganta manne mai zafi na narkewa da kuma inganta ruwan narkewa a cikin wani takamaiman iyaka.

④ NANO-SiO2 tare da ƙaramin kashi 4% na cikawa zai iya ƙara ƙarfin taurin kayan haɗin EVA/SiO2.

Nau'ikan cikawa da ake amfani da su wajen gyaran cikawa na EVA suna ƙara ƙaruwa, amma har yanzu akwai matsaloli da yawa a gyaran cikawa, yadda ake inganta watsawar cikawa a cikin matrix na EVA, da sauransu. Magance waɗannan matsalolin yana taimakawa wajen ƙara inganta aikin EVA.

02. Gyaran Haɗawa

Haɗawa da gyara EVA na iya inganta haɗin halayen polymers daban-daban, ta yadda EVA za ta iya samun sabbin halaye da kuma inganta aikin wani ɓangare. Haɗa EVA da sauran polymers tare da kyakkyawan jituwa muhimmin bangare ne na binciken gyaran EVA a cikin 'yan shekarun nan.

① Idan aka ƙara 15% EVA-g-MAH a cikin tsarin haɗakar EVA/halogen-free flame retardant copoly polyester (P-PET), za a iya inganta jituwarsa, kwararar tsari da kuma hana harshen wuta.

② A cikin tsarin haɗakar EVA/mai yawan polyethylene (HDPE), idan abun cikin HDPE ya kai kashi 15%, halayen injina na zare masu juyawa da haɗe-haɗe sune mafi kyau.

③ A cikin tsarin haɗakar EVA/NBR, ana iya samun mafi girman zafin jiki na thermal ta hanyar ƙara oxidized diisobenzotride (DCP).

Tare da haɓaka fasahar polymer alloy ta ƙarni na uku, kamar fasahar hanyar sadarwa ta polymer da aka haɗa, fasahar vulcanization mai ƙarfi,fasahar fitar da martani, fasahar haɗa ƙwayoyin halitta, da sauransu, za a haɓaka kayan haɗin EVA masu inganci da inganci don biyan buƙatun fasahar injiniya daban-daban don kayan aiki.

03. Sauran Gyara

Baya ga binciken gargajiya kan cikawa da haɗa EVA, an kuma sami babban ci gaba a bincike a fannin dasa sinadarai da haɗa EVA a cikin 'yan shekarun nan, wanda ya kafa harsashi mai kyau don haɓaka ƙarin nau'ikan samfuran EVA.

① Ana amfani da Benzoyl peroxide (BPO) a matsayin wakili mai haɗa kai don inganta saurin dawo da siffar kayan.

② An samo polymer na EVA-g-PU ta hanyar narkewar dasawa, wanda ya sami ƙarfi mai ƙarfi da tsawaitawa a lokacin karyewa fiye da kayan da aka yi amfani da su. Kuma ƙara prepolymers na PU kuma yana iya inganta aikin kwanciyar hankali na zafi na EVA yadda ya kamata.