Isimiso nezimpawu zamakhemikhali ashaya amakhemikhali

Amakhemikhali ashaya amakhemikhali Ama-ejenti amakhemikhali afuthwayo nawo angahlukaniswa abe yizinhlobo ezimbili eziyinhloko: amakhemikhali aphilayo namakhemikhali angavamile. Kunezinhlobo eziningi zamakhemikhali ashaya amakhemikhali angokwemvelo, kuyilapho ama-ejenti wokushaya amakhemikhali angaphili. Amakhemikhali okuqala okushaya amakhemikhali (cishe ngo-1850) ayengama-carbonate nama-bicarbonate. Lawa makhemikhali akhipha i-CO2 lapho efudunyezwa, futhi ekugcineni afakwa esikhundleni senhlanganisela ye-bicarbonate ne-citric acid ngoba eyokugcina inomphumela omuhle kakhulu wokubikezela. Ama-ejenti amagwebu anamuhla amahle kakhulu anezinto zamakhemikhali ezifanayo nezingenhla. Ziyi-polycarbonates (eyokuqala yiPoly-carbonic
acids) exutshwe nama-carbonates.

Ukubola kwe-polycarbonate kuyindlela yokuphela komzimba, ngo-320 ° F
Kungakhishwa cishe i-100cc ngegramu ye-asidi. Lapho i-CO2 yesobunxele nangakwesokudla iqhutshelwa phambili ifinyelela ku-390 ° F, kuzokhishwa igesi eyengeziwe. Isimo sokuphela kokuphendula kokubola kungaletha izinzuzo ezithile, ngoba ukushabalalisa ukushisa ngesikhathi senqubo yegwebu kuyinkinga enkulu. Ngaphezu kokuba ngumthombo wegesi okhihliza amagwebu, lezi zinto zivame ukusetshenziswa njengama-nucleating agents wezinto ezenziwa amagwebu ngokomzimba. Kukholakala ukuthi amangqamuzana okuqala akhiwa lapho i-ejenti yamakhemikhali eshaya abola ahlinzeka indawo yokufuduka kwegesi ekhishwa yi-ejenti yokushaya ngokomzimba.

Ngokuphambene nama-ejenti amagwebu angajwayelekile, kunezinhlobo eziningi zama-organic chemical foam agents ongakhetha kuzo, futhi amafomu awo omzimba nawo ahlukile. Eminyakeni embalwa edlule, kuhlolwe amakhulu emakhemikhali aphilayo angasetshenziswa njengama-blower agents. Kunezinqubo eziningi ezisetshenziselwa ukwahlulela. Okubaluleke kakhulu yilezi: ngaphansi kwezimo zejubane elilawulekayo kanye nokushisa okungaqagelwa, inani legesi elikhishwayo alilikhulu nje kuphela, kodwa futhi liyazala; amagesi nokuqina okukhiqizwa ukusabela akunabuthi, futhi kuhle ukwenza i-polymerization ekhihlizayo. Izinto akufanele zibe nemiphumela emibi, njengombala noma iphunga elibi; ekugcineni, kunenkinga yezindleko, nayo ebaluleke kakhulu. Labo bantu abasebenza amagwebu abasetshenziswe embonini namuhla bahambisana kakhulu nalezi zindlela.

I-ejenti ene-foam enezinga lokushisa eliphansi ikhethwa kuma-ejenti amaningi atholakala ngamakhemikhali. Inkinga enkulu okufanele ibhekwe ukuthi ukushisa kokubola kwe-ejenti enegwebu kufanele kuhambisane nokushisa okusebenzayo kwepulasitiki. Ama-ejenti amabili wokushaywa kwamakhemikhali aphilayo amukelwe kabanzi ngamazinga aphansi okushisa i-polyvinyl chloride, i-polyethylene ephansi kakhulu kanye nezinhlaka ezithile ze-epoxy. Owokuqala yi-toluene sulfonyl hydrazide (TSH). Le yimpuphu ephuzi futhi enoshukela onokubola okubalelwa ku-110 ° C. Igremu ngalinye likhiqiza cishe i-115cc ye-nitrogen nomswakama othile. Uhlobo lwesibili izimbambo ze-bis (benzenesulfonyl), noma i-OBSH. Le ejenti enegwebu ingasetshenziswa kakhulu ezinhlelweni zokusebenza ezinokushisa okuphansi. Le nto ingu-powder omhlophe omhlophe futhi ukushisa kwayo okujwayelekile kokubola kungu-150 ° C. Uma i-activator efana ne-urea noma i-triethanolamine isetshenziswa, leli zinga lingancishiswa lifike ku-130 ° C. Igremu ngalinye lingakhipha ugesi oyi-125cc, ikakhulukazi i-nitrogen. Umkhiqizo oqinile ngemuva kokubola kwe-OBSH yi-polymer. Uma isetshenziswa kanye ne-TSH, inganciphisa iphunga.

Isisebenzisi esinamagagasi aphezulu asezingeni lokushisa eliphezulu, njenge-ABS engamelana nokushisa, i-polyvinyl chloride eqinile, amanye amapulasitiki we-polypropylene aphansi nobunjiniyela, njenge-polycarbonate nenayiloni, qhathanisa ukusetshenziswa kwama-ejenti afutha ngamazinga okushisa aphezulu wokubola afanelekile. I-Toluenesulfonephthalamide (TSS noma i-TSSC) iyimpuphu emhlophe enhle kakhulu enokushisa kokubola okungaba ngu-220 ° C nokukhishwa kwegesi okungu-140cc ngegramu ngayinye. Ngokuyinhlanganisela enkulu ye-nitrogen ne-CO2, nenani elincane le-CO ne-ammonia. Le ejenti yokushaya ivame ukusetshenziselwa i-polypropylene ne-ABS ethile. Kepha ngenxa yokushisa kokubola kwayo, ukusetshenziswa kwayo ku-polycarbonate kunqunyelwe. Enye i-tetrazole (5-PT) esezingeni eliphakeme lokushisa eshisiwe isetshenziswe ngempumelelo ku-polycarbonate. Iqala ukubola kancane cishe ku-215 ° C, kepha ukukhiqizwa kwegesi akukukhulu. Isamba esikhulu segesi ngeke sikhishwe kuze kufike izinga lokushisa kuze kufike ku-240-250 ° C, futhi leli banga lokushisa likulungele kakhulu ukucubungulwa kwe-polycarbonate. Ukukhiqizwa kwegesi cishe
175cc / g, ikakhulukazi i-nitrogen. Ngaphezu kwalokho, kukhona okunye okuphuma ku-tetrazole okwenziwa. Banokushisa okubolile okuphezulu futhi bakhipha igesi engaphezulu kwe-5-PT.

Ukushisa okucubungula kwama-thermoplastics amakhulu kakhulu ezimboni ze-azodicarbonate kunjengoba kuchaziwe ngenhla. Ibanga lokushisa lokucubungula le-polyolefin eminingi, i-polyvinyl chloride ne-styrene thermoplastics ingu-150-210 ° C
. Ngalolu hlobo lweplastiki, kukhona uhlobo oluthile lokushaywa oluthembekile ongalusebenzisa, okungukuthi, i-azodicarbonate, eyaziwa nangokuthi i-azodicarbonamide, noma i-ADC noma i-AC ngamafuphi. Esimweni sayo esimsulwa, iyimpuphu ephuzi / e-orange cishe ku-200 ° C
Qala ukubola, futhi inani legesi elikhiqizwe ngesikhathi sokubola ngu
I-220cc / g, igesi ekhiqizwayo ikakhulukazi i-nitrogen ne-CO, nenani elincane le-CO2, futhi iqukethe ne-ammonia ngaphansi kwezimo ezithile. Umkhiqizo wokubola oqinile uyi-beige. Ayikwazi ukusetshenziswa kuphela njengenkomba yokubola okuphelele, kepha futhi ayinamphumela omubi kumbala wepulasitiki opholile.

I-AC isiphenduke i-ejenti ekhiqiza amagwebu esetshenziswa kabanzi ngezizathu eziningi. Mayelana nokukhiqizwa kwegesi, i-AC ingenye yezinto ezisebenza ngempumelelo kakhulu ezinegwebu, kanti igesi eliyikhiphayo inekhono eliphakeme kakhulu elenza amagwebu. Ngaphezu kwalokho, igesi ikhishwa ngokushesha ngaphandle kokulahlekelwa ukulawula. I-AC nemikhiqizo yayo eqinile yizinto ezinobuthi obuphansi. I-AC futhi ingesinye sezinto ezishibhile zokushaya amakhemikhali, hhayi kuphela ekusebenzeni kahle kokukhiqizwa kwegesi ngegramu ngayinye, kepha futhi kusuka ekukhiqizeni igesi ngedola kushibhile impela.

Ngaphezu kwezizathu ezingenhla, i-AC ingasetshenziswa kabanzi ngenxa yezici zayo zokubola. Izinga lokushisa nejubane legesi ekhishiwe lingashintshwa, futhi lingashintshwa libe ngu-150-200 ° C
Cishe zonke izinhloso ezingaphakathi kwesilinganiso. Ukwenza kusebenze, noma izithasiselo zesenzo zishintsha izici zokubola zamakhemikhali ashaya amakhemikhali, le nkinga kuxoxwe ngayo ekusetshenzisweni kwe-OBSH ngenhla. I-AC isebenza kangcono kakhulu kunanoma iyiphi enye i-ejenti yokushaya amakhemikhali. Kunezithasiselo ezahlukahlukene, okokuqala, usawoti wensimbi unganciphisa ukushisa kokubola kwe-AC, futhi izinga lokwehla kuncike kakhulu ohlotsheni nenani lezithasiselo ezikhethiwe. Ngaphezu kwalokho, lezi zithasiselo zineminye imiphumela, njengokushintsha izinga lokukhishwa kwegesi; noma ukudala isikhathi sokulibaziseka noma sokungeniswa ngaphambi kokuqala kokuphendula kokubola. Ngakho-ke, cishe zonke izindlela zokukhishwa kwegesi kule nqubo zingahle zenziwe ngokungeyena.

Usayizi wezinhlayiya ze-AC uphinde uthinte inqubo yokubola. Ngokuvamile, ekushiseni okunikeziwe, kukhulu ubukhulu besilinganiso sezinhlayiyana, kuhamba kancane ukukhishwa kwegesi. Lesi simo sibonakala kakhulu kumasistimu anezishoshovu. Ngalesi sizathu, ubukhulu bezinhlayiya ze-AC yokuhweba ngama-microns angu-2-20 noma amakhulu, futhi umsebenzisi angakhetha ngokuthanda kwakhe. Amaprosesa amaningi athuthukise izinhlelo zawo zokwenza kusebenze, kanti abanye abakhiqizi bakhetha izingxube ezahlukahlukene ezenziwe ngaphambi kokusebenza ezinikezwe abakhiqizi be-AC. Kunama-stabilizers amaningi, ikakhulukazi lawo asetshenziselwa i-polyvinyl chloride, futhi izingulube ezithile zizosebenza njengezishoshovu ze-AC. Ngakho-ke, kufanele uqaphele lapho ushintsha ifomula, ngoba izici zokubola ze-AC zingashintsha ngokufanele.

I-AC etholakala embonini inamamaki amaningi, hhayi kuphela ngosayizi wezinhlayiyana nohlelo lokuqalisa, kepha futhi nangokuya ngamanzi. Isibonelo, ukufaka okufakiwe ku-AC kungakhuphula uketshezi nokusabalalisa kwe-AC powder. Lolu hlobo lwe-AC lulungele kakhulu i-PVC plastisol. Ngoba i-ejenti enegwebu ingasakazeka ngokuphelele ku-plastisol, lokhu kuyinkinga esemqoka yekhwalithi yomkhiqizo wokugcina wepulasitiki. Ngaphezu kokusebenzisa amamaki ane-fluidity enhle, i-AC nayo ingahlakazeka ku-phthalate noma kwezinye izinhlelo zokuphatha. Kuzoba lula ukuphatha njengoketshezi.


Isikhathi Iposi: Jan-13-2021