Umthi wendalo kunye nesinyithi bezizizinto zokwakha ezibalulekileyo ebantwini kangangeminyaka engamawaka. Iipolymers zokwenziwa esizibiza ngokuba ziiplastiki ziyimveliso yakutshanje eyaqhuma kwinkulungwane yama-20.
Zombini iintsimbi kunye neeplastiki zineempawu ezifanelekileyo zokusetyenziswa kwimizi-mveliso nakwezorhwebo. Iintsimbi ziqinile, ziqinile, kwaye zihlala zinyamezela umoya, amanzi, ubushushu, kunye noxinzelelo oluqhubekayo. Nangona kunjalo, zikwafuna izixhobo ezingaphezulu (oko kuthetha ukuba zibiza kakhulu) ukuvelisa nokucoca iimveliso zazo. Iplastiki inika eminye yemisebenzi yesinyithi ngelixa ifuna ubunzima obuncinci kwaye ingabizi kakhulu ukuyivelisa. Iimpawu zazo zinokwenziwa ngokwezifiso phantse kuyo nayiphi na indlela yokusetyenziswa. Nangona kunjalo, iiplastiki zorhwebo ezingabizi kakhulu zenza izinto ezimbi zokwakha: izixhobo zeplastiki azilunganga, kwaye akukho mntu ufuna ukuhlala endlwini yeplastiki. Ukongeza, zihlala zicocwa ngamafutha efosili.
Kwezinye iindlela zokusebenza, imithi yendalo inokukhuphisana neentsimbi kunye neeplastiki. Uninzi lwamakhaya eentsapho akhiwe ngeefreyimu zomthi. Ingxaki kukuba imithi yendalo ithambile kakhulu kwaye yonakaliswa lula ngamanzi ukuba ingathathelwa indawo yiplastiki kunye nesinyithi uninzi lwexesha. Iphepha lakutshanje elipapashwe kwijenali iMatter liphonononga ukudalwa kwezinto zomthi eziqinileyo ezoyisa le mida. Olu phando lufikelele kwisiphelo ekudalweni kweemela zomthi kunye nezikhonkwane. Ingakanani imela yomthi kwaye uza kuyisebenzisa kungekudala?
Ulwakhiwo lwemithi olunemicu luquka malunga ne-50% ye-cellulose, i-polymer yendalo eneempawu zokuqina ezilungileyo ngokwethiyori. Isiqingatha esiseleyo sesakhiwo somthi ikakhulu yi-lignin kunye ne-hemicellulose. Ngelixa i-cellulose yenza imicu emide, eqinileyo enika umthi umqolo wokuqina kwawo kwendalo, i-hemicellulose ayinasakhiwo siqinileyo kwaye ngoko ke ayincedi nganto kumandla omthi. I-Lignin izalisa izithuba eziphakathi kwemicu ye-cellulose kwaye yenza imisebenzi eluncedo kwimithi ephilayo. Kodwa ngenjongo yabantu yokudibanisa umthi kunye nokubopha imicu ye-cellulose ngokuqinileyo, i-lignin yaba ngumqobo.
Kolu phononongo, umthi wendalo wenziwe ngomthi oqinileyo (HW) ngamanyathelo amane. Okokuqala, umthi ubiliswa kwi-sodium hydroxide kunye ne-sodium sulfate ukususa i-hemicellulose kunye ne-lignin. Emva kolu nyango lwamachiza, umthi uba mkhulu ngokuwucinezela kwi-press kangangeeyure ezininzi kubushushu begumbi. Oku kunciphisa izithuba zendalo okanye ii-pores emthini kwaye kuphucula ukubopha kweekhemikhali phakathi kweefayibha ze-cellulose ezikufutshane. Okulandelayo, umthi ucinezelwa kwi-105° C (221° F) kangangeeyure ezimbalwa ukuze kugqitywe uxinano, uze womiswe. Ekugqibeleni, umthi untywiliselwa kwi-oyile yeminerali kangangeeyure ezingama-48 ukuze imveliso egqityiweyo ingangeni manzi.
Enye yeempawu zoomatshini zezinto zokwakha bubulukhuni bokugoba, obuyindlela yokulinganisa amandla azo okumelana nokuguquguquka xa zicinezelwe ngamandla. Idayimani inzima kunentsimbi, inzima kunegolide, inzima kunemithi, kwaye inzima kunefoam yokupakisha. Phakathi kovavanyo oluninzi lobunjineli olusetyenziselwa ukumisela ubulukhuni, njengobulukhuni beMohs obusetyenziswa kwi-gemology, uvavanyo lweBrinell lolunye lwazo. Ingcamango yalo ilula: ibhere yebhola yesinyithi eqinileyo icinezelwa kumphezulu wovavanyo ngamandla athile. Linganisa ububanzi bokugoba okujikelezayo okwenziwe yibhola. Ixabiso lobulukhuni beBrinell libalwa kusetyenziswa ifomula yemathematika; xa sithetha ngokurhabaxa, okukhona umngxuma ibhola iwubetha mkhulu, kokukhona izinto zithambile. Kolu vavanyo, i-HW inzima ngokuphindwe ka-23 kunomthi wendalo.
Uninzi lwemithi yendalo enganyangwanga iya kutsala amanzi. Oku kunokwandisa imithi kwaye ekugqibeleni kutshabalalise iimpawu zayo zokwakha. Ababhali basebenzise ukuntywila kweeminerali iintsuku ezimbini ukwandisa ukumelana namanzi kwe-HW, okwenza ukuba ibe manzi ngakumbi ("yoyike amanzi"). Uvavanyo lokungatyi manzi lubandakanya ukubeka ithontsi lamanzi phezu komphezulu. Okukhona umphezulu umanzi ngakumbi, kokukhona amathontsi amanzi eba yingqukuva. Umphezulu othanda amanzi ("othanda amanzi"), kwelinye icala, usasaza amathontsi ngokuthe tyaba (kwaye emva koko afunxe amanzi ngokulula). Ke ngoko, ukuntywila kweeminerali akupheleli nje ekunyuseni kakhulu ukungatyi manzi kwe-HW, kodwa kukwathintela umthi ekufunxeni umswakama.
Kwezinye iimvavanyo zobunjineli, iimela ze-HW zisebenze ngcono kancinci kuneemela zesinyithi. Ababhali bathi imela ye-HW ibukhali ngokuphindwe kathathu kunemela ethengiswayo. Nangona kunjalo, kukho isilumkiso kwesi siphumo sinomdla. Abaphandi bathelekisa iimela zetafile, okanye oko sinokukubiza ngokuba ziimela zebhotolo. Ezi azijoliswanga ekubeni zibukhali kakhulu. Ababhali babonisa ividiyo yemela yabo isika i-steak, kodwa umntu omdala oqinileyo unokusika i-steak efanayo ngecala elibuthathaka lefolokhwe yesinyithi, kwaye imela ye-steak ingasebenza ngcono kakhulu.
Kuthekani ngezikhonkwane? Isikhonkwane esinye se-HW sinokubethelelwa ngokulula kwisiqwenga samaplanga amathathu, nangona singenazo iinkcukacha njengoko kulula xa sithelekiswa nezikhonkwane zentsimbi. Izikhonkwane zomthi zinokubamba amaplanga kunye, zixhathise amandla aza kuwaqhekeza, ngokuqina okufanayo nezikhonkwane zentsimbi. Nangona kunjalo, kuvavanyo lwazo, amabhodi kuzo zombini iimeko ahluleka ngaphambi kokuba naziphi na izikhonkwane zingasebenzi, ngoko ke izikhonkwane ezomeleleyo azizange zibonakale.
Ngaba iinzipho ze-HW zingcono ngezinye iindlela? Iipegi zomthi zikhaphukhaphu, kodwa ubunzima besakhiwo abubangelwa bubunzima beepegi ezisibambayo. Iipegi zomthi aziyi kugqwala. Nangona kunjalo, aziyi kuthintelwa ngamanzi okanye zibole.
Akukho mathandabuzo ukuba umbhali uphuhlise inkqubo yokwenza umthi ube namandla kunomthi wendalo. Nangona kunjalo, ukusetyenziswa kwezixhobo kuyo nayiphi na imisebenzi kufuna uphando olongezelelekileyo. Ngaba inokuba nexabiso eliphantsi kwaye ingabi nazixhobo njengeplastiki? Ngaba ingakhuphisana nezinto zesinyithi eziqinileyo, ezinomtsalane ngakumbi, nezingasetyenziswa kwakhona ngokungenammiselo? Uphando lwabo luphakamisa imibuzo enomdla. Ubunjineli obuqhubekayo (kwaye ekugqibeleni imakethi) buya kuyiphendula.
Ixesha lokuthumela: Epreli-13-2022
