Pickering Emulsion-Assisted Construction Of Phase-Change Microcapsules Stabilized Bu Regenerated Bagasse

Biomass materials have received great attention due to their green,eco-friendly,renewable,degradable and biocompatible properties,and have widely used in the fields of papermaking,chemicals,food,medicine,and cosmetics.Bagasse,as a typical biomass material,is a by-product of the sugar industry.The yield of bagasse is large,but the utilization rate is extremely low.In addition,the underutilized bagasse can easily cause environmental pollution and waste of resources.Therefore,it is necessary to explore a way to realize the high value-added application of bagasse.In this dissertation,phosphoric acid was used to dissolve the bagasse to prepare the regenerated bagasse suspension.Pickering emulsion was further prepared by using regenerated bagasse as emulsifier.And the phase change microcapsules were constructed by the Pickering emulsion template method.In the first part,the bagasse was dissolved in phosphoric acid in a water bath at30°C,regenerated in water to obtain regenerated bagasse,and then subjected to high pressure homogenization to prepare a uniformly dispersed suspension.Infrared spectroscopy and X-ray diffraction tests showed that the chemical structure of the regenerated bagasse did not change,and the crystallinity of the regenerated bagasse dropped significantly.In TEM characterization,the regenerated bagasse showed a mixed state of coexistence of short fibers and particles.When the concentration is above 0.7 wt%,the standing stability of the regenerated bagasse suspension becomes poor.In addition,a Pickering emulsion was prepared using regenerated bagasse as a stabilizer and dimethicone as an oil phase.The effects of suspension concentration and oil-water mass ratio on the droplets size and stability of the Pickering emulsion were investigated.The regenerated bagasse can be also used as a stabilizer for other organic solvents such as n-tetradecanol,and n-eicosane,etc.to prepare Pickering emulsion,which confirm that the regenerated bagasse has good emulsifying properties.Based on the above work,in the second part,the phase change microcapsules were prepared by the Pickering emulsion template method by taking advantage of the good emulsifying properties of regenerated bagasse,using n-eicosane and methyl methacrylate as raw materials.The effects of core-shell ratio,different cross-linking agents and different paraffins on the appearance and coating rate of microcapsules were discussed,and the thermal cycle stability and sealing performance of the prepared samples were tested.The prepared phase change microcapsules were added to gypsum and combined with it to prepare phase change microcapsule/gypsum composite materials,and then the microstructure,energy storage and temperature regulation properties of the prepared composite materials were characterized.Results show that:(1)the phosphoric acid system can hydrolyze bagasse at30 °C.After dissolving and regenerating,the regenerated bagasse suspension can be obtained by high-pressure homogenization;(2)the regenerated bagasse suspension has good emulsifying and static stability properties within a certain concentration range.It can emulsify various organic solvents to prepare Pickering emulsion;(3)the regenerated bagasse stabilized Pickering emulsion can assist in the construction of paraffin-based phase change microcapsules with different core-shell ratios,different cross-linking agents and different phase transition temperatures.Most importantly,the resulting phase change microcapsules have good thermal stability and sealing performance;(4)the phase change microcapsule/gypsum composite with excellent energy storage and temperature regulation properties was prepared by using regenerated bagasse stabilized Pickering emulsion.The heating rate of the composites added with 28 wt% of microcapsules is slow,and the microcapsules play the role of energy storage and heat preservation during the heating process.