Iimpawu zeekhemikhali ze-HPMC

IHydroxypropyl Methylcellulose (HPMC)yi-non-ionic cellulose ether, eyimveliso eguqulwe ngokweekhemikhali eyenziwe yi-reaction ye-cellulose yendalo ene-propylene oxide kunye ne-methyl chloride emva kwe-alkalization. I-HPMC izinzile kakuhle ngokwasemzimbeni nangokweekhemikhali kwaye isetyenziswa kakhulu kumayeza, izixhobo zokwakha, ukutya, izinto zokuthambisa kunye nezinye iindawo. Iimpawu zayo zeekhemikhali zezi zilandelayo:

1. Iimpawu zesakhiwo se-molecular

Isiseko esisisiseko se-HPMC sivela kwi-cellulose yendalo, eyenziwe ziiyunithi zeglucose ezidityaniswe ziibhondi ze-β-1,4-glycosidic ukwenza uthotho lwe-macromolecular oluthe ngqo. Ukungeniswa kwamaqela e-hydroxypropyl kunye ne-methoxy kuthatha indawo yamaqela e-hydroxyl (-OH) kwi-cellulose molecular chain, ngaloo ndlela kuyinika iipropati ezikhethekileyo. Eli nqanaba lokutshintshwa (oko kukuthi, inqanaba lokutshintshwa kwamaqela e-methoxy kunye ne-hydroxypropyl) linempembelelo ebalulekileyo ekunyibilikeni, kwiimpawu zejeli kunye nokuzinza kwe-HPMC.

2. Ukunyibilika

I-HPMC yipolymer eqhelekileyo enyibilikayo emanzini engeyiyo i-ionic enokuvuvukala ngokukhawuleza emanzini abandayo kwaye yenze isisombululo se-colloidal esicacileyo okanye esikhanyayo. Nangona kunjalo, emanzini ashushu, i-HPMC ayilula ukuyinyibilikisa kwaye iya kwenza ijeli kumaqondo obushushu aphezulu. Le propati yejeli eguqulwayo ngomnye weempawu ezibalulekileyo zomzimba nezekhemikhali ze-HPMC. Ukongeza emanzini, i-HPMC inokunyibilikiswa nakwizinyibilikisi ezithile ze-polar organic, ezifana nesinyibilikisi esixutyiweyo se-ethanol namanzi, i-dimethylformamide, njl.

3. Uzinzo lobushushu kunye nokufakwa kwe-gel

I-HPMC inozinzo oluhle kakhulu kubushushu. Njengoko ubushushu bunyuka, ii-molecular chain ze-HPMC kwisisombululo samanzi ziya kudibana nokuphelelwa ngamanzi emzimbeni ukuze zenze isakhiwo senethiwekhi esinemilinganiselo emithathu, kwaye kuya kwenzeka utshintsho ukusuka kwisisombululo ukuya kwijeli. Ubushushu be-gelation buxhomekeke kumxholo kunye nobunzima be-molecular yezinto ezithatha indawo. Ngokubanzi, i-HPMC enomxholo ophezulu we-hydroxypropyl inobushushu obuphezulu be-gelation, ngelixa i-HPMC enomxholo ophezulu we-methoxy inobushushu obuphantsi be-gelation.

I-Gelation iyaguqulwa, kwaye ijeli iya kunyibilika ibuyele kwimeko yolwelo emva kokuba ipholile. Le propati ye-thermogel eyahlukileyo yenza i-HPMC isoloko isetyenziswa njengesixhobo esikhutshwa rhoqo kwishishini lamayeza kwaye isetyenziswa kwishishini lezinto zokwakha ukuphucula ukusebenza kolwakhiwo lwe-mortar.

4. Uzinzo lwe-pH

I-HPMC igcina uzinzo oluhle kuluhlu lwe-pH oluyi-3 ~ 11. Olu luhlu lubanzi lozinzo lwe-pH luvumela ukuba lusetyenziswe kwiindawo ezahlukeneyo ngaphandle kokuwohloka okanye ukuna kwemvula. Xa ixabiso le-pH lingaphantsi kwe-3 okanye ngaphezulu kwe-11, isisombululo sinokonakala okanye sinciphe ngenxa yoxinzelelo olukhulu lwee-ion ze-hydrogen okanye ii-ion ze-hydroxide, nto leyo ekhokelela ekuncipheni kokusebenza.

5. Ukusabela kweekhemikhali

Ngenxa yokuba kukho amaqela e-hydroxyl angafakwanga endaweni yawo kwi-molecule ye-HPMC, isagcina umsebenzi othile weekhemikhali kwaye ingafumana ezi mpendulo zilandelayo:

Impendulo ye-Esterification: Phantsi kweemeko ezifanelekileyo, i-HPMC inokusabela kunye ne-acyl chloride, ii-anhydrides, njl.njl. ukwenza ii-esters;

Impendulo ye-Etherification: Amaqela e-hydroxyl aseleyo angaqhubeka nokusabela kunye nee-etherifying agents (ezifana nee-epoxides) ukutshintsha ngakumbi izinga lokutshintshwa kunye nokusebenza kwe-HPMC;

Impendulo ye-oxidation: Xa kukho ii-oxidants ezinamandla (ezifana ne-potassium permanganate, i-sodium hypochlorite), uthotho lweemolekyuli ze-HPMC lunokwaphuka, nto leyo ebangela ukuncipha kwe-viscosity;

I-Hydrolysis reaction: Phantsi kwesenzo se-asidi ezinamandla okanye iziseko ezinamandla, i-hydroxypropyl kunye ne-methoxy side chains zinokufakelwa i-hydrolyzed, nto leyo ebangela utshintsho kwisakhiwo se-molecular kunye nokuwohloka kokusebenza.

Ngokubanzi, phantsi kweemeko eziqhelekileyo zokusetyenziswa, iipropati zeekhemikhali ze-HPMC zizinzile.

6. Ukubola kwezinto eziphilayo

I-HPMC ivela kwi-cellulose yendalo, ngoko ke inokonakala ibe ziishukela ezincinci zemolekyuli kwindawo ethile yebhayoloji (njengokuba isetyenziswa ziintsholongwane), ize ekugqibeleni ibole ibe yi-carbon dioxide namanzi. Oku kubola kakuhle kwenza i-HPMC ihlangabezane neemfuno zezinto ezinobuhlobo nokusingqongileyo.

7. Ukuhambelana nezinye izinto

Njenge-polymer engeyiyo i-ionic, i-HPMC ihambelana kakuhle neentlobo ngeentlobo zezongezo ze-ionic okanye ezingezizo i-ionic (ezifana nezinye iipolymer, ii-surfactants, izithambisi, njl.njl.). Ingakumbi kwinkqubo yokwenza, ingasebenza neentlobo ngeentlobo zezithako zamayeza, izondlo, imibala, njl.njl. ngaphandle kwemvula okanye ukuhluzwa.

Uzinzo lwe-HPMC kwindawo enoxinzelelo oluphezulu lwe-electrolyte luya kuchaphazeleka, kwaye ityuwa eninzi ye-inorganic inokubangela ukuba i-viscosity yesisombululo inciphe okanye ide ifikelele.

8. Ukumelana nee-enzyme

Xa kuthelekiswa ne-cellulose yendalo,I-HPMCinokumelana okuphezulu kwi-cellulase ngenxa yokutshintshwa kwamanye amaqela e-hydroxyl, kwaye ayiboli lula zii-enzymes eziqhelekileyo. Olu phawu luyinika ithuba lokukhululwa kade kwamayeza kwindawo yesisu.

I-Hydroxypropyl methylcellulose (HPMC) yinto yendalo ye-polymer eguqulwe ngokweekhemikhali enokunyibilika kakuhle kwamanzi, i-heat gelation, uzinzo lwe-pH, uzinzo lweekhemikhali kunye nokubola kwezinto eziphilayo. Ngenxa yesakhiwo sayo esahlukileyo kunye neempawu zeekhemikhali, i-HPMC isetyenziswa kakhulu kwicandelo lezonyango, izixhobo zokwakha, ii-coating, ukutya, izinto zokuthambisa, njl.njl., ngakumbi kwiifomyula ezifuna ukuqina, ukukhululwa okulawulwayo, ukwenziwa kwefilimu, ukumiswa, i-emulsification kunye neminye imisebenzi.