Hydroxypropylmethylcellulose (HPMC) chinhu chave chinhu chikuru mumaindasitiri mazhinji nekuda kwemabasa ayo akawanda. Inowanzoshandiswa sechikafu chinowedzera, chinosimbisa muzvizoro, uye kunyange sechinhu chekurapa mumishonga yakawanda. Chinhu chakasiyana cheHPMC maitiro ayo ethixotropic, ayo anoibvumira kushandura maitiro ekupenya uye kuyerera kwemvura pasi pemamwe mamiriro. Pamusoro pezvo, HPMC ine simba iri, inoratidza thixotropy kunyangwe iri pasi petembiricha yegel.
Thixotropy inoitika muHPMC kana mhinduro ikatanga kuonda kana kumanikidzwa kwaiswa kana kumutswa, zvichikonzera kudzikira kwekusimba kwesimba. Maitiro aya anogonawo kudzoserwa shure; kana kusimba kwabviswa uye mhinduro ikasiyiwa kuti igare, kusimba kwesimba kunodzokera zvishoma nezvishoma pakakwirira. Hunhu uhwu hwakasiyana hunoita kuti HPMC ive chinhu chinokosha mumaindasitiri mazhinji sezvo ichibvumira kushandiswa zviri nyore uye kugadziriswa kuri nyore.
Semushonga usiri weionic hydrocolloid, HPMC inozvimba mumvura kuti igadzire gel. Kukura kwekuzvimba uye gelling kunoenderana nehuremu hwemamorekuru uye huwandu hwepolymer, pH uye tembiricha yemushonga. HPMC ine huremu hwakawanda uye inogadzira gel ine huremu hwakawanda, nepo HPMC ine huremu hwakaderera uye inogadzira gel isina kusimba zvakanyanya. Zvisinei, pasinei nekusiyana uku mukushanda, mhando dzese dzeHPMC dzinoratidza thixotropy nekuda kwekuchinja kwemaumbirwo kunoitika padanho remamorekuru.
Maitiro e-thixotropic eHPMC anokonzerwa nekurongeka kwemacheni epolymer nekuda kwekusvuta kweshear. Kana shear stress ikashandiswa kuHPMC, macheni epolymer anorongeka akananga kune stress inoshandiswa, zvichikonzera kuparadzwa kwechimiro chenetwork chetatu-dimensional chaivepo pasina stress. Kukanganiswa kwenetwork kunoita kuti viscosity yesolution iderere. Kana stress ikabviswa, macheni epolymer anorongwazve akanangana nekwaaive pakutanga, achivakazve network uye achidzorera viscosity.
HPMC inoratidzawo thixotropy iri pasi petembiricha yegelling. Tembiricha yegel ndiyo tembiricha iyo polymer chains inobatana nayo kuti igadzire network ine mativi matatu, ichigadzira gel. Zvinoenderana nehuwandu, huremu hwemolecular uye pH yemhinduro yepolymer. Gel inobuda ine viscosity yakakwira uye haichinji nekukurumidza kana yamanikidzwa. Zvisinei, pasi petembiricha yegelation, mhinduro yeHPMC yakaramba iri mvura, asi ichiri kuratidza maitiro ethixotropic nekuda kwekuvapo kwechimiro chenetwork chakagadzirwa zvishoma. Network inoumbwa nezvikamu izvi inoputsika kana yamanikidzwa, zvichikonzera kudzikira kwe viscosity. Maitiro aya anobatsira mumashandisirwo mazhinji apo mhinduro dzinofanira kuyerera zviri nyore kana dzamutswa.
HPMC ikemikari inoshandiswa zvakasiyana-siyana ine hunhu hwakasiyana, chimwe chazvo chiri maitiro ayo ethixotropic. HPMCs dzine hunhu uhwu, dzichiratidza thixotropy kunyangwe tembiricha iri pasi pejeli. Hunhu uhwu hunoita kuti HPMC ive chinhu chakakosha mumaindasitiri mazhinji anoda mhinduro dzinobata kuyerera kuri nyore kuti ive nechokwadi chekuti kushandiswa kwayo kwakanyatsonaka. Pasinei nekusiyana kwehunhu pakati peHPMCs dzine hunhu hwakanyanya uye husina kusimba, hunhu hwadzo hwethixotropic hunoitika nekuda kwekurongeka uye kukanganiswa kwechimiro chenetwork chakagadzirwa zvishoma. Nekuda kwehunhu hwadzo hwakasiyana, vaongorori vanogara vachiongorora mashandisirwo akasiyana-siyana eHPMC, vachitarisira kugadzira zvigadzirwa zvitsva uye kupa mhinduro dziri nani kune vatengi pasi rese.
Nguva yekutumira: Nyamavhuvhu-23-2023