Fluid gel production and tribological behaviour of alginate and agar

• Main Author: Fernández Farrés, Isabel
• Published: University of Birmingham 2015
• Subjects: 660; TP Chemical technology
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.665777

This thesis aims to develop a better understanding of both the formation and properties of fluid gels using the microstructural engineering approach. In general terms, the two main outcomes of this research are: (1) advancing the knowledge on the structuring processes for fluid gel design and (2) developing new models for the structure-function relationship for fluid gels. There is currently a lack of understanding on the formation of thermo-stable fluid gels due to the absence of processing techniques for their production. In this thesis, two processing techniques were developed to produce thermo-stable fluid gels from alginates. The first technique is a continuous process comprising a pin stirrer device with a Ca2+-injection system. The second production technique used a cup and vane rheometer combined with an internal gelation method. With this technique, the kinetics of fluid gel formation was studied as function of applied shear rate, calcium concentration and alginate molecular weight. With regard to the structure-function relationship, the lubricating behaviour of agar fluid gels was explored using a new approach which consisted in decoupling the contributions of the continuous phase and the particulate gelled phase. The effect of added co-solutes on lubricating properties of agar fluid gels was also explored.