Study On The Mechanism Of Gelation Of β-carboxypropionate Hydroxypropylmethyl Cellulose In An Aqueous Solution

Cellulose derivatives have important applications value due to the gelation of their aqueous solution. But people have different opinion about its gelation mechanism. In this paper, we prepared five differentβ-carboxypropionate hydroxypropylmethyl cellulose(CPHPMC) and study its gelation mechanism.In this work, we study the gelation behaviour of aqueous solutions ofβ-carboxypropionate hydroxypropylmethyl cellulose ether with the method of rheology,UV-vis and conductance etc. Furthermore, we study the process of gelation by using additives and rectifing pH to change condition of CPHPMC solution. Then explore the mechanism of gelation of CPHPMC. The result show that the carboxypropionate make CPHPMC had lower gelation temperature than HPMC. The gelation process is depand on the content and distributing of carboxypropionate, and some factor like additive and pH condition can also affect it. Therefore, we point out our mechanism of CPHPMC gelation process which depend on the macromolecular assembly theory that the gelation of CPHPMC is due to the assemble interaction of chain segments and chain nodes within/inter polymeric chains driverd via hydrogen-bonded(H-bonding), hydrophobic effect and Van der Waals force etc. This assembly can make physical entanglement nodes between polymer chain and form network structure with water medium as the gelation process of CPHPMC aqueous solution begin. The degree of gelaton process is depend on the ability of chain segments assembly within/inter CPHPMC polymers. Further more, the results show that temperature, pH value, ion concentration, outside force and addtives could affect this assembly process that lead the change of gelation process and hydrogel properties.