Hydroxyethyl cellulose (HEC) ndi polima yopanda ionic, yosungunuka m'madzi yochokera ku cellulose kudzera mukusintha kwamankhwala. Imagwiritsidwa ntchito kwambiri m'mafakitale osiyanasiyana chifukwa cha mawonekedwe ake apadera, monga kukhuthala, kukhazikika, komanso luso lopanga mafilimu. M'magwiritsidwe omwe kukhazikika kwa pH ndikofunikira, kumvetsetsa momwe HEC imachitira pamitundu yosiyanasiyana ya pH ndikofunikira.
Kukhazikika kwa pH kwa HEC kumatanthawuza kuthekera kwake kosunga umphumphu wake, mawonekedwe a rheological, ndi magwiridwe antchito osiyanasiyana a pH. Kukhazikika kumeneku ndikofunikira pakugwiritsa ntchito monga zinthu zosamalira anthu, mankhwala, zokutira, ndi zida zomangira, pomwe pH ya malo ozungulira imatha kusiyana kwambiri.
Kapangidwe:
HEC nthawi zambiri imapangidwa pochita ma cellulose ndi ethylene oxide pansi pamikhalidwe yamchere. Izi zimapangitsa kuti magulu a hydroxyl a msana wa cellulose alowe m'malo ndi magulu a hydroxyethyl (-OCH2CH2OH). Digiri ya m'malo (DS) imasonyeza kuchuluka kwa magulu a hydroxyethyl pa unit ya anhydroglucose mu tcheni cha cellulose.
Katundu:
Kusungunuka: HEC imasungunuka m'madzi ndipo imapanga njira zomveka bwino komanso zowoneka bwino.
Viscosity: Imawonetsa pseudoplastic kapena kumeta ubweya wa ubweya, kutanthauza kuti mamasukidwe ake amachepa akamameta ubweya. Katunduyu amathandizira pakugwiritsa ntchito komwe kumayenda ndikofunikira, monga utoto ndi zokutira.
Kukhuthala: HEC imapereka mamasukidwe akayendedwe ku mayankho, kuwapangitsa kukhala amtengo wapatali ngati wowonjezera mumitundu yosiyanasiyana.
Kupanga filimu: Kutha kupanga mafilimu osinthika komanso owonekera pamene zouma, zomwe zimakhala zopindulitsa pakugwiritsa ntchito monga zomatira ndi zokutira.
pH Kukhazikika kwa HEC
Kukhazikika kwa pH kwa HEC kumakhudzidwa ndi zinthu zingapo, kuphatikizapo kapangidwe ka mankhwala a polima, kuyanjana ndi chilengedwe chozungulira, ndi zowonjezera zilizonse zomwe zilipo popanga.
Kukhazikika kwa pH kwa HEC mumitundu yosiyanasiyana ya pH:
1. Acidic pH:
Pa acidic pH, HEC nthawi zambiri imakhala yokhazikika koma imatha kukhala ndi hydrolysis kwa nthawi yayitali pansi pazovuta za acidic. Komabe, m'zinthu zambiri zothandiza, monga zopangira chisamaliro chaumwini ndi zokutira, kumene acidic pH ikukumana, HEC imakhalabe yokhazikika mkati mwa pH (pH 3 mpaka 6). Kupitilira pH 3, chiwopsezo cha hydrolysis chimawonjezeka, zomwe zimapangitsa kuti pang'onopang'ono kuchepe ndi magwiridwe antchito. Ndikofunika kuyang'anira pH ya mankhwala omwe ali ndi HEC ndikusintha ngati kuli kofunikira kuti mukhale okhazikika.
2. pH yosalowerera ndale:
HEC imasonyeza kukhazikika bwino pansi pa pH ya ndale (pH 6 mpaka 8). Mtundu wa pH uwu ndiwofala pamagwiritsidwe ambiri, kuphatikiza zodzoladzola, mankhwala, ndi zinthu zapakhomo. Mapangidwe opangidwa ndi HEC amasunga mamasukidwe ake, makulidwe ake, komanso magwiridwe antchito mkati mwa pH iyi. Komabe, zinthu monga kutentha ndi mphamvu ya ionic zingakhudze kukhazikika ndipo ziyenera kuganiziridwa pakupanga mapangidwe.
3. pH yamchere:
HEC imakhala yosakhazikika pansi pamikhalidwe yamchere poyerekeza ndi acidic kapena ndale pH. Pama pH apamwamba (pamwamba pa pH 8), HEC ikhoza kuwonongeka, zomwe zimapangitsa kuchepa kwa viscosity ndi kutaya ntchito. Alkaline hydrolysis ya kulumikizana kwa etha pakati pa cellulose msana ndi magulu a hydroxyethyl amatha kuchitika, zomwe zimapangitsa kuti ma chain scission ndichepetse kulemera kwa maselo. Choncho, m'mapangidwe a alkaline monga zotsukira kapena zomangira, ma polima kapena ma stabilizer amatha kukhala abwino kuposa HEC.
Zomwe Zimakhudza Kukhazikika kwa pH
Zinthu zingapo zingakhudze kukhazikika kwa pH kwa HEC:
Degree of Substitution (DS): HEC yokhala ndi DS yapamwamba imakhala yokhazikika pa pH yotakata chifukwa cha kuchuluka kwa magulu a hydroxyl ndi magulu a hydroxyethyl, zomwe zimawonjezera kusungunuka kwamadzi ndi kukana hydrolysis.
Kutentha: Kutentha kokwera kumatha kufulumizitsa machitidwe amankhwala, kuphatikiza hydrolysis. Choncho, kusunga kutentha koyenera ndi kukonza kutentha n'kofunika kuti muteteze kukhazikika kwa pH ya HEC-containing formulations.
Mphamvu ya Ionic: Kuchuluka kwa mchere wa mchere kapena ma ions ena mu kapangidwe kake kungakhudze kukhazikika kwa HEC pokhudza kusungunuka kwake ndi kuyanjana ndi mamolekyu amadzi. Mphamvu ya Ionic iyenera kukonzedwa kuti muchepetse zosokoneza.
Zowonjezera: Kuphatikizika kwa zowonjezera monga zowonjezera, zosungirako, kapena ma buffering agents zingakhudze kukhazikika kwa pH kwa mapangidwe a HEC. Kuyesa kufananiza kuyenera kuchitidwa kuti zitsimikizire kugwirizana kowonjezera ndi kukhazikika.
Zofunsira ndi Zolinga Zopangira
Kumvetsetsa kukhazikika kwa pH kwa HEC ndikofunikira kwa opanga mafakitale osiyanasiyana.
Nazi malingaliro ena okhudzana ndi ntchito:
Zopangira Zosamalira Munthu: Mu ma shampoos, zodzoladzola, ndi zodzoladzola, kusunga pH mkati mwamtundu wofunidwa (kawirikawiri kuzungulira ndale) kumatsimikizira kukhazikika ndi ntchito ya HEC monga wothandizira ndi woyimitsa.
Mankhwala: HEC imagwiritsidwa ntchito poyimitsa pakamwa, njira za ophthalmic, ndi mapangidwe apamutu. Mapangidwe amayenera kupangidwa ndikusungidwa pansi pamikhalidwe yomwe imasunga bata la HEC kuti zitsimikizire kuti zinthu zikuyenda bwino komanso nthawi ya alumali.
Zopaka ndi Paints: HEC imagwiritsidwa ntchito ngati rheology modifier ndi thickener mu utoto wamadzi ndi zokutira. Opanga amayenera kulinganiza zofunikira za pH ndi njira zina zogwirira ntchito monga kukhuthala, kusanja, ndi kupanga mafilimu.
Zida Zomangamanga: Muzitsulo za cementitious, HEC imagwira ntchito yosungira madzi ndikuwongolera ntchito. Komabe, zinthu za alkaline mu simenti zimatha kutsutsa kukhazikika kwa HEC, kufunikira kosankha mosamalitsa ndikusintha kapangidwe.
Hydroxyethyl cellulose (HEC) imapereka mawonekedwe ofunikira komanso magwiridwe antchito pamagwiritsidwe osiyanasiyana. Kumvetsetsa kukhazikika kwake kwa pH ndikofunikira kwa opanga kupanga mapangidwe okhazikika komanso ogwira mtima. Ngakhale HEC imasonyeza kukhazikika kwabwino pansi pa pH ya ndale, kulingalira kuyenera kupangidwira malo a acidic ndi amchere kuti ateteze kuwonongeka ndikuwonetsetsa kuti ntchito yabwino. Posankha giredi yoyenera ya HEC, kukhathamiritsa magawo opangira, ndikukhazikitsa malo oyenera osungira, okonza amatha kugwiritsa ntchito mapindu a HEC kumadera osiyanasiyana a pH.
Nthawi yotumiza: Mar-29-2024