Preparation And Properties Of Micro And Nano Capsule Phase Change And Heat And Moisture Of Gypsum Composite Materials

In the field of energy-saving construction techniques, the phase change materialsexchange and store energy using latent heat in phase change process to control theambient temperature. However, due to the presence of leaking, phase separation andcorrisive issures of phase change materials, to develop micro-nano phase changecapsule building composites with temperature/humidity-adjusting functions becomesone of the difficulties. The composites will utilize their own energy to meet thecomfort living conditions requirements.This paper selects different types of phase-change material as the core,polystyrene material as the inner and hydrophilic chitosan as the shell. A fineminiemulsions interfacial polymerization had been used to obtain good performance ofdouble-shell micro-nano phase change capsules and the various factors affecting theperformance of micro and nano capsules preparation phase transitions were tested andanalyzed. Determine the best process parameters: shell/core ratio of1:1, emulsifier of3%, phaco time10min, co-emulsifier of0.3%, initiator of0.1%, the initial reactiontemperature is40?, stirring speed is500r/min.The structures, morphologies, particle sizes of double-shelled capsules wereseparately characterized by Infrared Spectroscopy, SEM, Laser particle size Analyzerand other methods, etc. Test results showed that: The hydrophilic chitosan on the outershell of double-shell capsules grafted well with methyl methacrylate on the inner shell,showing a large number of produced spherical capsules with sphericity integrity. The core materials were of densed structure wrapped by the outer shell, including nanoscale particles.In addition, the thermal wet performance of double shell capsuleswere tested by DSC, Saturated saline solution method. Both single and double-shellcapsules contain a suitable phase transition temperature and enthalpy; compared withthe single-shell micro-nano capsules, double-shell capsules showed better moistureabsorption and desorption capacity. When the relative humidity was97.3%, moisturecontent reached0.1797g/g and when relative humidity is11.3%, desorption amountwas0.1415g/g.The thermal wet performance of gypsum-based composite phase change weretested. The results showed that: The heat storage capacity increased of gypsum-basedphase-change composite capsule with micro-nano phase change by increasing itsincorporation, and closely related to the content of the core material; The moistureabsorption and desorption capacity and rate increased of gypsum-based phase-changecomposite capsule with micro-nano phase change by increasing its incorporation. Theabsorption rate is a significant increase when the content is30%and within20h, tendsto balance and maximum the rate in20~40h. Same time, the mechanism of temperatureand humidity of gypsum-based phase change were discussed. The micro-nano phasechange capsule of gypsum-based main regulated temperature on the environment,without being micro-nano phase change capsule filling pore and a hydrophilic shellcapsules main regulated on the relative humidity of the surrounding environment.