Isintu sisebenzise izinto zemvelo ze-polymeric njengokhuni, isikhumba noboya kusukela ekuqaleni komlando, kodwa ama-polymers okwenziwa angenzeka kuphela ngemva kokuthuthukiswa kobuchwepheshe benjoloba ngawo-1800.I-Ž yokuqala yokwenziwa kwe-polymer material, i-celluloid, yasungulwa nguJohn Wesley Hyatt ngo-1869, isuka ku-cellulose nitrate kanye ne-camphor.Impumelelo enkulu kuma-polymer okwenziwa kwakuwukusungulwa kwe-Bakelite ngu-Leo Hendrik Baekeland ngo-1907. Umsebenzi ka-Hermann Staudinger ngawo-1920 wabonisa ngokusobala imvelo yama-macromolecular yamaketango amade amayunithi aphindaphindayo.1 Igama elithi 'polymer' livela kwelesiGrikhi, futhi lisho 'okuningi. izingxenye'.Ukukhula okusheshayo kwemboni ye-polymer kwaqala ngaphambi nje kweMpi Yezwe Yesibili, ngokuthuthukiswa kwama-polymers e-acrylic, i-polystyrene, inayiloni, i-polyurethanes kanye nokwethulwa okulandelayo kwe-polyethylene, i-polyethylene terephthalate, i-polypropylene namanye ama-polymers ngawo-1940 kanye nawo-1950.Nakuba kuphela amathani ayizigidi ezingu-1 akhiqizwa ngo-1945, ukukhiqizwa kwamapulasitiki ngevolumu kudlula okwensimbi ngo-1981, futhi igebe belilokhu likhula ngokuqhubekayo kusukela ngaleso sikhathi.
Ama-polymer ahlanzekile awavamile ukucutshungulwa ngokwawo.Ahlanganiswa nezinye izinto, ngokuvamile ngokuxuba kwemishini noma ukuncibilika kwesimo ukuze kukhiqizwe amapellets, izimpushana noma ama-kes azosetshenziswa ekucubunguleni okulandelayo.2 Imikhiqizo enjalo ehlanganisiwe ibizwa ngokuthi 'ipulasitiki', okusho ukuthi 'okuphendulekayo' ngesiGreki.Izinhlanganisela zingase zibandakanye ama-Ž llers (ukunciphisa izindleko), iziqinisi, amanye ama-polymer, ama-colorants, ama-ame retardants, ama-stabilizer (ukuvimbela ukuwohloka kokukhanya, ukushisa noma ezinye izici zemvelo) kanye nezinsiza ezihlukahlukene zokucubungula.
Ama-polymer okwenziwa angahlukaniswa ngezigaba ezimbili.I-Thermoplastics (ivolumu enkulu kakhulu) ingancibilika ngokushisisa, iqiniswe ngokupholisa futhi incibilikiswe ngokuphindaphindiwe.Izinhlobo ezinkulu i-polyethylene (PE), i-polypropylene(PP), i-polystyrene (PS), i-polyvinyl chloride (PVC), i-polycarbonate (i-PC), i-polymethyl methacrylate (PMMA), i-polyethylene terephthalate (PET) ne-polyamide (PA, inayiloni).Ama-Thermosets enziwa lukhuni ukusetshenziswa kokushisa nokucindezela, ngenxa yokuphambana, okungukuthi ukwakhiwa kwamanethiwekhi angunaphakade ezinhlangothi ezintathu.Azikwazi ukuthanjiswa ngokushisisa ukuze zicutshungulwe kabusha.I-Bakelite, i-epoxies kanye nama-polyurethanes amaningi ama-thermosets.
Ukubuka konke kwamanje kunikezelwe kuphela ekucutshungulweni kwe-thermoplastics.I-Thermoplastics yezentengiselwano ihlelwe ngokuya ngokusebenza kwayo 'njengempahla' (ukusebenza okuphansi, okufana ne-PE, PP, PS ne-PVC), 'Engineering' (njenge-PC, inayiloni ne-PET) noma 'okuthuthukisiwe' (ukusebenza okuphezulu, njengokusebenza okuphezulu, njenge i-liquid crystal polymers (LCPs), i-polyphenylene sulphide (PPS) kanye ne-polyetheretherketone (PEEK)).Ukukhula kokuqhuma obekulindelwe kwezobunjiniyela nama-polymer athuthukile akuzange kwenzeke.Ukusetshenziswa kwamapulasitiki bekulokhu kukhula ngokuqhubekayo phakathi namashumi amathathu eminyaka edlule, kodwa ikakhulukazi esigabeni sempahla.Njengamanje, ama-polymers ezimpahla afinyelela ku-88% wevolumu ekhiqizwayo, amapulasitiki obunjiniyela ama-3 ~ 12% futhi athuthuke ngaphansi kuka-1%.Nakuba amanani entengo yama-polymer athuthukile ngekhilogremu ephakeme kakhulu kunalawo ama-polymers wempahla, ukubaluleka kwawo emhlabeni jikelele emnothweni kusekuncane kakhulu.
Amapulasitiki ezinto ezithengiswayo anamandla aphansi nokuqina uma eqhathaniswa nezinsimbi noma izitsha zobumba, futhi avame ukukhombisa ukungena ngaphansi kwamandla asetshenzisiwe.Futhi zinemikhawulo yokushisa ekusebenziseni kwazo njengama-solids (iningi liyancibilika ebangeni elingu-100–250°C).I-tensile moduli yamapulasitiki wempahla ingu ~1 GPa (uma kuqhathaniswa no-210 GPa wensimbi).Ukuthuthukiswa kwe-Signi-Ž cant kungafinyelelwa ngokuhambisana kwamaketanga e-polymer.Empeleni, amabhondi e-carbon–carbon anamandla kakhulu, futhi ama-polyethylene eyodwa ye-Ž lament akhiqizwa enamanani e-modulus adlula awensimbi.Ukuma okuphezulu kungafinyelelwa ngamasu okucubungula akhethekile, isibonelo i-extrusion kanye nokudweba okulandelayo emazingeni okushisa aphansi.Emazingeni okushisa aphansi amaketanga e-polymer anokunyakaza okulinganiselwe, futhi umumo usala ngemva kokwelula.Okutholwe kwakamuva kanye nokuthuthukiswa kwesayithi elilodwa, ama-catalyst asekelwe ku-metallocene kubangele amabanga amasha ama-polymers wempahla alawule ukwakheka kwamangqamuzana anezakhiwo ezithuthukisiwe.
Ukukhiqizwa komhlaba wonke kwama-polymers kukhuphuke3 kusuka kumathani ayizigidi ezingama-27 ngo-1975 kuya ~ kumathani ayizigidi ezingama-200 ngonyaka ngo-2000 futhi kusakhula.Ngokombiko wakamuva, ukuthunyelwa okungu-4 kwemikhiqizo yepulasitiki e-USA ngo-2000 kwafinyelela ku-$330 billion, kanti izimboni ezihlinzeka ngempahla esezingeni eliphezulu zadayiswa ngamaRandi ayizigidi eziyizinkulungwane ezingama-90, okwenza isamba saminyaka yonke safinyelela ku-$420 billion.Isamba sokuqashwa silinganiselwa ezigidini ezi-2 .4 - cishe ama-2% abasebenzi base-US.Ukukhula kwemboni ye-polymer kuwumphumela wenhlanganisela eyingqayizivele yezakhiwo zemikhiqizo yepulasitiki, ehlanganisa ukubunjwa okulula nokwakhiwa, ukuminyana okuphansi, ukumelana nokugqwala, ukufakwa kukagesi nokushisa, kanye nokuqina okuvumayo kanye nokuqina ngeyunithi ngayinye yesisindo.
Isikhathi sokuthumela: Feb-04-2018