1. Sebenzisa udidi

Ngokweempawu ezahlukeneyo zokusetyenziswa kweeplastiki ezahlukeneyo, iiplastiki zihlala zahlulwe zibe ziintlobo ezintathu: iiplastiki eziqhelekileyo, iiplastiki zobunjineli kunye neeplastiki ezikhethekileyo.

①Iplastiki ngokubanzi

Ngokubanzi ibhekisa kwiiplastiki ezinemveliso enkulu, ukusetyenziswa okubanzi, ukwakheka okuhle kunye nexabiso eliphantsi. Kukho iintlobo ezintlanu zeplastiki ngokubanzi, ezizezi i-polyethylene (PE), i-polypropylene (PP), i-polyvinyl chloride (PVC), i-polystyrene (PS) kunye ne-acrylonitrile-butadiene-styrene copolymer (ABS). Ezi ntlobo zintlanu zeplastiki zibalwa uninzi lwezinto ezisetyenziswa kwiplastiki, kwaye ezinye zinokwahlulwa zibe ziintlobo zeplastiki ezikhethekileyo, ezifana ne: PPS, PPO, PA, PC, POM, njl., azisetyenziswa kakhulu kwiimveliso zemihla ngemihla, ikakhulu zisetyenziswa kwiindawo eziphezulu ezifana noshishino lobunjineli kunye netekhnoloji yokhuselo lwesizwe, njengeemoto, i-aerospace, ulwakhiwo, kunye nonxibelelwano. Ngokwendlela yokwahlulahlula iplastiki, iiplastiki zinokwahlulwa zibe zii-thermoplastics kunye neeplastiki ze-thermosetting. Kwiimeko eziqhelekileyo, iimveliso ze-thermoplastic zinokuphinda zisetyenziswe, ngelixa iiplastiki ze-thermosetting zingenako. Ngokweempawu ezibonakalayo zeplastiki, zinokwahlulwa zibe zizinto ezibonakalayo, ezikhanyayo nezingabonakaliyo, ezifana nePS, PMMA, AS, PC, njl.njl. eziziiplastiki ezibonakalayo, kwaye uninzi lwezinye iiplastiki ziplastiki ezingacacanga.

Iimpawu kunye nokusetyenziswa kweplastiki ezisetyenziswa rhoqo:

1. I-Polyethylene:

I-polyethylene esetyenziswa rhoqo inokwahlulwa ibe yi-polyethylene enoxinano oluphantsi (LDPE), i-polyethylene enoxinano oluphezulu (HDPE) kunye ne-polyethylene enoxinano oluphantsi oluthe ngqo (LLDPE). Phakathi kwezi zintathu, i-HDPE ineempawu ezingcono zobushushu, zombane nezoomatshini, ngelixa i-LDPE kunye ne-LLDPE zinokuguquguquka okungcono, iimpawu zempembelelo, iimpawu zokwenza ifilimu, njl. I-LDPE kunye ne-LLDPE zisetyenziswa kakhulu kwiifilimu zokupakisha, iifilimu zezolimo, ukuguqulwa kweplastiki, njl., ngelixa i-HDPE inoluhlu olubanzi lwezicelo, ezifana neefilimu, iipayipi, kunye neemfuno zemihla ngemihla zokujova.

2. I-Polypropylene:

Ngokuthe ngqo, i-polypropylene ineentlobo ngeentlobo, iindlela ezisetyenziswa ngayo zintsonkothile, kunye noluhlu olubanzi lweendawo. Ezi ntlobo ziquka i-homopolymer polypropylene (homopp), i-block copolymer polypropylene (copp) kunye ne-random copolymer polypropylene (rapp). Ngokwesicelo, i-Homopolymerization isetyenziswa kakhulu kwiindawo zokuzoba ucingo, i-fiber, i-injection, ifilimu ye-BOPP, njl. I-Copolymer polypropylene isetyenziswa kakhulu kwiindawo zokujova izixhobo zasekhaya, izinto ezilungisiweyo, iimveliso zokujova zemihla ngemihla, iipayipi, njl. njl., kwaye i-random polypropylene isetyenziswa kakhulu kwiimveliso ezibonakalayo, iimveliso ezisebenza kakhulu, iipayipi ezisebenza kakhulu, njl.

3. I-Polyvinyl chloride:

Ngenxa yexabiso layo eliphantsi kunye neempawu zokuzibamba umlilo, inoluhlu olubanzi lokusetyenziswa kwicandelo lokwakha, ngakumbi kwiipayipi zomsele wamanzi amdaka, iingcango zeplastiki kunye neefestile zentsimbi, iipleyiti, ulusu olungeyolwenziweyo, njl.

4. I-Polystyrene:

Njengohlobo lwezixhobo ezingabonakaliyo, xa kukho imfuneko yokukhanya, inoluhlu olubanzi lokusetyenziswa, njengezikhanyiso zezibane zeemoto, iindawo ezibonakalayo zemihla ngemihla, iikomityi ezibonakalayo, iithini, njl.njl.

5. I-ABS:

Yiplastiki yobunjineli eguquguqukayo eneempawu ezibalaseleyo zoomatshini nezobushushu. Isetyenziswa kakhulu kwizixhobo zasekhaya, iiphaneli, iimaski, iindibano, izixhobo, njl.njl., ingakumbi izixhobo zasekhaya, ezinje ngoomatshini bokuhlamba, ii-air conditioner, iifriji, iifeni zombane, njl.njl. Inkulu kakhulu kwaye inoluhlu olubanzi lokusetyenziswa ekuguquleni iplastiki.

②Iiplastiki zobunjineli

Ngokubanzi ibhekisa kwiiplastiki ezinokumelana namandla athile angaphandle, ezineempawu ezilungileyo zoomatshini, ukumelana nobushushu obuphezulu nobuphantsi, kwaye zinozinzo oluhle nobukhulu, kwaye zingasetyenziswa njengezakhiwo zobunjineli, ezifana ne-polyamide kunye ne-polysulfone. Kwiplastiki yobunjineli, yahlulwe yangamacandelo amabini: iiplastiki zobunjineli ngokubanzi kunye neeplastiki zobunjineli ezikhethekileyo. Iiplastiki zobunjineli zinokuhlangabezana neemfuno eziphezulu ngokweempawu zoomatshini, ukuqina, ukumelana nokugqwala, kunye nokumelana nobushushu, kwaye kulula ngakumbi ukuzicubungula kwaye zinokuthatha indawo yezinto zesinyithi. Iiplastiki zobunjineli zisetyenziswa kakhulu kumbane nakwi-elektroniki, kwiimoto, kulwakhiwo, kwizixhobo zeofisi, koomatshini, kwi-aerospace nakwamanye amashishini. Ukutshintsha iplastiki endaweni yentsimbi kunye neplastiki endaweni yomthi kuye kwaba yindlela yehlabathi.

Iiplastiki zobunjineli ngokubanzi ziquka: i-polyamide, i-polyoxymethylene, i-polycarbonate, i-modified polyphenylene ether, i-thermoplastic polyester, i-ultra-high molecular weight polyethylene, i-methylpentene polymer, i-vinyl alcohol copolymer, njl.

Iiplastiki zobunjineli ezikhethekileyo zahlulwe zibe ziintlobo ezidityanisiweyo nezingenadityanisiweyo. Iintlobo ezidityanisiweyo zezi: i-polyamino bismaleamide, i-polytriazine, i-polyimide edityanisiweyo, i-epoxy resin engangeni bushushu njalo njalo. Iintlobo ezingezizo ezidityanisiweyo zezi: i-polysulfone, i-polyethersulfone, i-polyphenylene sulfide, i-polyimide, i-polyether ether ketone (PEEK) njalo njalo.

③Iiplastiki ezikhethekileyo

Ngokubanzi ibhekisa kwiiplastiki ezinemisebenzi ekhethekileyo kwaye zingasetyenziswa kwizicelo ezikhethekileyo ezifana neenqwelo moya kunye neenqwelo moya. Umzekelo, ii-fluoroplastics kunye nee-silicones zinokumelana okugqwesileyo nobushushu obuphezulu, ukuzithambisa kunye neminye imisebenzi ekhethekileyo, kwaye iiplastiki eziqinisiweyo kunye neeplastiki ezinefoam zineempawu ezikhethekileyo ezifana namandla aphezulu kunye nokucushwa okuphezulu. Ezi plastiki ziphantsi kodidi lweeplastiki ezikhethekileyo.

a. Iplastiki eqinisiweyo:

Izinto ezisetyenzisiweyo zeplastiki eziqinisiweyo zinokwahlulwa zibe ziigranular (ezifana neplastiki eqinisiweyo yecalcium), iifayibha (ezifana nefayibha yeglasi okanye iplastiki eqinisiweyo yelaphu leglasi), kunye ne-flake (ezifana neplastiki eqinisiweyo ye-mica) ngokubonakala. Ngokwezinto ezisetyenzisiweyo, zinokwahlulwa zibe ziiplastiki eziqinisiweyo ezisekelwe ngelaphu (ezifana neplastiki eqinisiweyo yerag okanye iplastiki eqinisiweyo ye-asbestos), iiplastiki ezizaliswe yiminerali ezingaphiliyo (ezifana ne-quartz okanye iiplastiki ezizaliswe yi-mica), kunye neeplastiki eziqinisiweyo zefayibha (ezifana neplastiki eqinisiweyo ye-carbon fiber).

b. Igwebu:

Iiplastiki zefoam zinokwahlulwa zibe ziintlobo ezintathu: ifoam eqinileyo, eqina kancinci kunye neguquguqukayo. Ifoam eqinileyo ayinakuguquguquka, kwaye ubunzima bayo boxinzelelo bukhulu kakhulu. Iya kuguquguquka kuphela xa ifikelela kwixabiso elithile loxinzelelo kwaye ayinakubuyela kwimeko yayo yokuqala emva kokuba uxinzelelo luphelile. Ifoam eguquguqukayo iyaguquguquka, inobunzima obuphantsi boxinzelelo, kwaye kulula ukuyiguqula. Buyisela imeko yokuqala, ukuguquguquka okushiyekileyo kuncinci; ukuguquguquka kunye nezinye iimpawu zefoam eqinileyo ziphakathi kwefoam eqinileyo nethambileyo.

Ezimbini, udidi lwezinto ezibonakalayo nezekhemikhali

Ngokweempawu ezahlukeneyo zomzimba nezekhemikhali zeplastiki ezahlukeneyo, iiplastiki zinokwahlulwa zibe ziintlobo ezimbini: iiplastiki zethermosetting kunye neeplastiki zethermoplastic.

(1) I-Thermoplastic

Iithermoplastics (iiplastiki zeThermo): zibhekisa kwiiplastiki eziya kunyibilika emva kokufudumeza, zinokungena kwimold emva kokuphola, zize zinyibilike emva kokufudumeza; ukufudumeza nokupholisa kungasetyenziselwa ukuvelisa utshintsho oluguqukayo (ulwelo ←→oluqinileyo), ewe Oku kubizwa ngokuba lutshintsho lomzimba. Iithermoplastics zeenjongo ngokubanzi zinobushushu obusetyenziswa rhoqo obungaphantsi kwe-100°C. I-Polyethylene, i-polyvinyl chloride, i-polypropylene, kunye ne-polystyrene nazo zibizwa ngokuba ziiplastiki ezine zeenjongo ngokubanzi. Iiplastiki zeThermoplastic zahlulwe zaba zii-hydrocarbons, iivinyls ezinee-polar genes, ubunjineli, i-cellulose kunye nezinye iintlobo. Iba thambile xa ishushu, kwaye iba lukhuni xa ipholile. Inokuthanjiswa ngokuphindaphindiweyo kwaye iqine kwaye igcine imo ethile. Iyanyibilika kwiisolvents ezithile kwaye inepropathi yokunyibilika nokunyibilika. Iithermoplastics zine-insulation yombane egqwesileyo, ngakumbi i-polytetrafluoroethylene (PTFE), i-polystyrene (PS), i-polyethylene (PE), i-polypropylene (PP) inelahleko ephantsi kakhulu ye-dielectric constant kunye ne-dielectric. Kwizixhobo ze-insulation ze-frequency ephezulu kunye ne-voltage ephezulu. Ii-thermoplastics kulula ukuzibumba nokuzicoca, kodwa zinokumelana nobushushu obuphantsi kwaye kulula ukuzicoca. Ubungakanani bokucoca buyahluka ngokomthwalo, ubushushu bendalo, i-solvent, kunye nokufuma. Ukuze koyiswe obu buthathaka be-thermoplastics kwaye kuhlangatyezwane neemfuno zezicelo kwicandelo letekhnoloji yesithuba kunye nophuhliso lwamandla amatsha, onke amazwe aphuhlisa ii-resins ezingamelana nobushushu ezinokunyibilikiswa, ezifana ne-polyether ether ketone (PEEK) kunye ne-polyether sulfone (PES). , i-Polyarylsulfone (PASU), i-polyphenylene sulfide (PPS), njl. Izinto ezidityanisiweyo ezizisebenzisa njenge-matrix resin zineempawu eziphezulu zoomatshini kunye nokumelana neekhemikhali, zinokufakwa kwi-thermoform kwaye zifakwe kwi-weld, kwaye zinamandla angcono okucoca phakathi kwe-interlaminar kune-epoxy resin. Umzekelo, ukusebenzisa i-polyether ether ketone njenge-matrix resin kunye ne-carbon fiber ukwenza izinto ezidityanisiweyo, ukumelana nokudinwa kudlula oko kwe-epoxy/carbon fiber. Inokumelana okuhle nempembelelo, ukumelana okuhle kokucoca kubushushu begumbi, kunye nokusebenza kakuhle. Ingasetyenziswa rhoqo kwi-240-270°C. Yinto efanelekileyo yokukhusela ubushushu obuphezulu. Izinto ezidityanisiweyo ezenziwe nge-polyethersulfone njenge-matrix resin kunye ne-carbon fiber zinamandla aphezulu kunye nobunzima kwi-200°C, kwaye zinokugcina ukumelana okuhle kwempembelelo kwi--100°C; azinatyhefu, azitsha, azinamsi msi, kwaye azinakumelana nemitha. Ewe, kulindeleke ukuba zisetyenziswe njengecandelo eliphambili lenqwelo-moya, kwaye zinokubunjwa zibe yi-radome, njl.njl.

Iiplastiki ezidityaniswe nge-formaldehyde ziquka iiplastiki ze-phenolic, iiplastiki ze-amino (ezifana ne-urea-formaldehyde-melamine-formaldehyde, njl.njl.). Ezinye iiplastiki ezidityaniswe nge-cross-linked ziquka ii-polyester ezingagcwaliyo, ii-epoxy resins, kunye nee-phthalic diallyl resins.

(2) Iplastiki yokuseta ubushushu

Iiplastiki ze-thermosetting zibhekisa kwiiplastiki ezinokunyangeka phantsi kobushushu okanye ezinye iimeko okanye ezineempawu ezinganyibilikiyo (ukunyibilika), ezifana neeplastiki ze-phenolic, iiplastiki ze-epoxy, njl. Iiplastiki ze-thermosetting zahlulwe ngohlobo lwe-formaldehyde oludityanisiweyo kunye nezinye iintlobo ezidityanisiweyo. Emva kokucubungula ubushushu kunye nokubumba, imveliso ecociweyo enganyibilikiyo nenganyibilikiyo yenziwa, kwaye iimolekyuli ze-resin zidityaniswe kwisakhiwo senethiwekhi ngesakhiwo esithe nkqo. Ubushushu obandayo buya kubola butshabalalise. Iiplastiki ze-thermosetting eziqhelekileyo ziquka i-phenolic, i-epoxy, i-amino, i-unsaturated polyester, i-furan, i-polysiloxane kunye nezinye izinto, kunye neeplastiki ezintsha ze-polydipropylene phthalate. Zineengenelo zokuxhathisa ubushushu obuphezulu kunye nokuchasana nokuguquguquka xa kushushu. Ingxaki kukuba amandla oomatshini ngokubanzi akaphezulu, kodwa amandla oomatshini anokuphuculwa ngokongeza izizalisi ukwenza izinto ezifakwe i-laminated okanye izinto ezibunjiweyo.

Iiplastiki ze-thermosetting ezenziwe nge-phenolic resin njengezinto eziphambili zokwenza izinto, ezifana neplastiki ebunjiweyo ye-phenolic (eyaziwa ngokuba yiBakelite), zihlala ixesha elide, zizinzile ngokwemilinganiselo, kwaye ziyamelana nezinye izinto zeekhemikhali ngaphandle kwe-alkalis ezinamandla. Ii-fillers ezahlukeneyo kunye nezongezo zingongezwa ngokweemfuno ezahlukeneyo. Kwiintlobo ezifuna ukusebenza okuphezulu kobushushu, i-mica okanye i-glass fiber ingasetyenziswa njenge-filler; kwiintlobo ezifuna ukumelana nobushushu, i-asbestos okanye ezinye ii-fillers ezimelana nobushushu zingasetyenziswa; kwiintlobo ezifuna ukumelana nokushukuma komhlaba, iifayibha ezahlukeneyo ezifanelekileyo okanye irabha zingasetyenziswa njenge-fillers Kwaye ezinye ii-agents zokuqinisa ukwenza izinto ezinzima. Ukongeza, ii-phenolic resins eziguquliweyo ezifana ne-aniline, i-epoxy, i-polyvinyl chloride, i-polyamide, kunye ne-polyvinyl acetal nazo zingasetyenziselwa ukuhlangabezana neemfuno zezicelo ezahlukeneyo. Ii-phenolic resins zingasetyenziselwa ukwenza ii-phenolic laminates, ezibonakaliswa ngamandla aphezulu oomatshini, iipropati ezilungileyo zombane, ukumelana nokugqwala, kunye nokucutshungulwa okulula. Zisetyenziswa kakhulu kwizixhobo zombane eziphantsi kwamandla.

Ii-Aminoplast ziquka i-urea formaldehyde, i-melamine formaldehyde, i-urea melamine formaldehyde njalo njalo. Zineengenelo zokubumba okuqinileyo, ukumelana nokukrwela, ukungabi nambala, ukukhanya okukhanyayo, njl. Ukongeza izinto zombala kunokwenziwa iimveliso ezinemibala, ezaziwa ngokuba yi-electric jade. Ngenxa yokuba ayichaphazeleki yioyile kwaye ayichaphazeleki zii-alkalis ezibuthathaka kunye nezinyibilikisi ze-organic (kodwa ayimelani ne-asidi), ingasetyenziswa kwi-70°C ixesha elide, kwaye inokumelana ne-110 ukuya kwi-120°C kwixesha elifutshane, kwaye ingasetyenziswa kwiimveliso zombane. Iplastiki ye-Melamine-formaldehyde inobunzima obuphezulu kuneplastiki ye-urea-formaldehyde, kwaye inokumelana namanzi okungcono, ukumelana nobushushu, kunye nokumelana ne-arc. Ingasetyenziswa njengezinto zokukhusela ezimelana ne-arc.

Kukho iintlobo ezininzi zeplastiki ze-thermosetting ezenziwe nge-epoxy resin njengezinto eziphambili zokwenza imveliso, apho malunga ne-90% isekelwe kwi-bisphenol A epoxy resin. Inamathela kakuhle, i-insulation yombane, imelana nobushushu kwaye izinzile kwiikhemikhali, iyancipha kwaye ifunxa amanzi, kwaye inamandla afanelekileyo oomatshini.

Zombini i-polyester engagcwaliyo kunye ne-epoxy resin zinokwenziwa zibe yi-FRP, enamandla kakhulu oomatshini. Umzekelo, iplastiki eqinisiweyo yefayibha yeglasi eyenziwe nge-polyester engagcwaliyo ineempawu ezilungileyo zoomatshini kunye noxinano oluphantsi (i-1/5 ukuya kwi-1/4 yentsimbi kuphela, i-1/2 ye-aluminium), kwaye kulula ukuyicubungula kwiindawo ezahlukeneyo zombane. Iimpawu zombane kunye noomatshini zeplastiki ezenziwe nge-dipropylene phthalate resin zingcono kunezo zeplastiki ze-phenolic kunye ne-amino thermosetting. Ine-hygroscopicity ephantsi, ubungakanani bemveliso obuzinzileyo, ukusebenza kakuhle kokubumba, ukumelana ne-asidi kunye ne-alkali, amanzi abilayo kunye nezinye izinyibilikisi ze-organic. I-compound yokubumba ifanelekile ukuvelisa iindawo ezinesakhiwo esintsonkothileyo, ukumelana nobushushu kunye nobushushu obuphezulu. Ngokubanzi, ingasetyenziswa ixesha elide kuluhlu lobushushu oluyi--60 ~ 180℃, kwaye umgangatho wokuxhathisa ubushushu unokufikelela kwi-F ukuya kwi-H grade, ephezulu kunokumelana nobushushu kweplastiki ze-phenolic kunye ne-amino.

Iiplastiki zesilicone ezikwimo yesakhiwo se-polysiloxane zisetyenziswa kakhulu kwi-elektroniki nakwitekhnoloji yombane. Iiplastiki ze-silicone ezifakwe i-laminate ziqiniswa kakhulu ngelaphu leglasi; iiplastiki ezibunjiweyo ze-silicone zizaliswe kakhulu yi-fiber yeglasi kunye ne-asbestos, ezisetyenziselwa ukuvelisa iindawo ezimelana nobushushu obuphezulu, ii-frequency ephezulu okanye ii-submersible motors, izixhobo zombane, kunye nezixhobo ze-elektroniki. Olu hlobo lweplastiki lubonakaliswa yi-dielectric constant yayo ephantsi kunye nexabiso le-tgδ, kwaye aluchaphazeleki kangako yi-frequency. Isetyenziswa kumashishini ombane kunye ne-elektroniki ukumelana ne-corona kunye nee-arcs. Nokuba ukukhupha kubangela ukubola, imveliso yi-silicon dioxide endaweni ye-conductive carbon black. . Olu hlobo lwezinto lunokumelana nobushushu okubalaseleyo kwaye lungasetyenziswa rhoqo kwi-250°C. Iingxaki eziphambili ze-polysilicone ngamandla aphantsi oomatshini, ukunamathela okuphantsi kunye nokumelana neoyile okuphantsi. Iipolymers ezininzi ze-silicone eziguquliweyo ziye zaphuhliswa, ezifana neeplastiki ze-silicone eziguquliweyo ze-polyester kwaye zisetyenziswe kwitekhnoloji yombane. Ezinye iiplastiki ziplastiki ze-thermoplastic kunye ne-thermosetting. Umzekelo, i-polyvinyl chloride ngokubanzi yi-thermoplastic. IJapan iphuhlise uhlobo olutsha lwe-polyvinyl chloride engamanzi eyi-thermoset kwaye inobushushu bokubumba obuyi-60 ukuya kwi-140°C. Iplastiki ebizwa ngokuba yiLundex eMelika ineempawu zokucubungula i-thermoplastic, kunye neempawu zomzimba zeplastiki ze-thermosetting.

① Iiplastiki zeHydrocarbon.

Yiplastiki engeyiyo i-polar, eyahlulwe yaba yi-crystalline kunye ne-non-crystalline. Iiplastiki ze-hydrocarbon ze-crystalline ziquka i-polyethylene, i-polypropylene, njl.njl., kwaye iiplastiki ze-hydrocarbon ezingeyiyo i-crystalline ziquka i-polystyrene, njl.njl.

②Iiplastiki zeVinyl eziqulethe iijini ze-polar.

Ngaphandle kwee-fluoroplastics, uninzi lwazo zizinto ezibonakalayo ezingabonakaliyo ngekristale, kuquka i-polyvinyl chloride, i-polytetrafluoroethylene, i-polyvinyl acetate, njl. Uninzi lwee-vinyl monomers lunokufakelwa i-polymer ngee-radical catalysts.

③Iiplastiki zobunjineli be-thermoplastic.

Ikakhulu ziquka i-polyoxymethylene, i-polyamide, i-polycarbonate, i-ABS, i-polyphenylene ether, i-polyethylene terephthalate, i-polysulfone, i-polyethersulfone, i-polyimide, i-polyphenylene sulfide, njl. I-Polytetrafluoroethylene. I-polypropylene eguquliweyo, njl. nazo zibandakanyiwe kolu luhlu.

④ Iiplastiki ze-thermoplastic cellulose.

Iquka ikakhulu i-cellulose acetate, i-cellulose acetate butyrate, i-cellophane, i-cellophane njalo njalo.

Singasebenzisa zonke izinto zeplastiki ezingentla.
Phantsi kweemeko eziqhelekileyo, i-PP yodidi lokutya kunye ne-PP yodidi lwezonyango zisetyenziselwa iimveliso ezifana neamacephe. Ipipetteyenziwe ngezinto zeHDPE, kwayeityubhu yokuvavanyangokubanzi yenziwe ngezinto ze-PP okanye ze-PS zodidi lwezonyango. Sisenazo iimveliso ezininzi, sisebenzisa izinto ezahlukeneyo, kuba singabantuumngundoumenzi, phantse zonke iimveliso zeplastiki zinokuveliswa