Cross⁃linked microcapsules were prepared by suspension polymerization with polystyrene as the wall material and 58# paraffin as the core material. The effects of polymerization temperature, initiator dosage, crosslinker type and core⁃wall ratio on microcapsules were investigated. The structure, morphology, heat storage performance and thermal stability of microcapsules were characterized by FT⁃IR, SEM, DSC and TG. The experimental results show that the microcapsules prepared by the polymerization temperature of 80 ℃ and the initiator AIBN 2% have good spherical shape. The microcapsules prepared by the cross⁃linking agent DVB have less clastic debris, no agglomeration and good thermal stability. The microcapsules prepared by the core wall ratio of 3∶1 have a phase transition enthalpy of 152.2 J/g, a core material content of 82.2%, and the best heat storage performance.

Acrylic resin is widely used in construction, leather chemicals and other fields because of its low cost, good weather resistance and excellent film formation. However, its surface energy is high and its mechanical properties are poor, which limits its application. In order to improve this deficiency, acrylate was used as the main monomer, dodecafluoroheptyl methacrylate was used as a functional monomer, and trimethylolpropane triacrylate (TMPTA) was used as a crosslinking agent, the hydrophobic fluorinated acrylic resin was synthesized by a shell emulsion polymerization method. The reaction conditions were investigated. The stability and particle size of the emulsion as well as the tensile strength, hardness, hydrophobic angle, chemical structure and thermal stability of the emulsion film were characterized. The results indicate that the addition of TMPTA can effectively improve the tensile strength, hardness and thermal stability of the emulsion film. When TMPTA accounts for 2% of shell monomer mixture, the average particle size of the emulsion is 157.2 nm, and the conversion rate is 97.7%. The comprehensive performance of the emulsion film is best: the water absorption rate is 12.3%, and the decomposition temperature is 394 °C when the weight loss rate is 50%. The angle is 98.9°, the tensile strength is 3.5 MPa, and the hardness is 71.2 HA. Compared with the fluorine⁃containing acrylic resin, the tensile strength is increased by 159.2%, and the thermal stability can be improved by 34.6 °C.

Phase change material microcapsules (MicroPCMs) with polystyrene as shell material and paraffin as core material were prepared by suspension polymerization. The influence of emulsifying time, the dosages of crosslinking agent (DVB), polymerization times and the mass ratios of core and shell has been studied on the properties of phase change microcapsules, such as chemical compositions, surface morphologies, thermal storage properties and stabilities of the microcapsules were characterized by fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The results showed that the emulsifying time had no significant influence on the thermal properties of microcapsules. The microcapsule showed better morphology with less wrinkles and less debris when the dosage of divinybenzene(DVB) was 6∶1. The microcapsule prepared with the polymerization time of 3 h had good morphology, relatively uniform size, high latent heat of phase change and high content of core wax. As the mass ratio of the core and wall material increases, the melting temperature of the content of core material (paraffin) increases successively. When the mass ratio of the core and wall material is 3∶1, the latent heat of prepared microcapsule with good thermal stability increases to 125.2 J/g and the content of core material(paraffin) reaches up to 80.9%.

The phase change microcapsules with methyl methacrylate as the shell material and 58# paraffin as the core material were prepared by suspension polymerization. The effects of some factors on the properties of the microcapsules were studied, such as the amounts of emulsifiers and initiators, the mass ratios of the core and shell materials. Chemical compositions, surface morphologies, thermal properties and stabilities of the microcapsules were characterized by Fourier transform infrared (FT⁃IR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The results showed that when the mass fractions of emulsifier PVP and initiator AIBN were 7.0% and 3.9%, respectively, the microcapsules had the best morphology. When the mass ratio of the core and shell material was 3∶1, the microcapsule had a regular spherical shape with a smooth surface. At the same time, the microcapsule with the high enthalpy of phase change had a high heat storage property and stability. The quantity of heat involved in phase transition was 126.97 J/g and the content of paraffin wax as the core material was 85.4%.

Alkylphenol polyoxyethylene ether surfactants have good emulsifying properties and are common raw materials for silicone oil emulsifiers, however, the by-products and their final metabolites in the production process are highly toxic and can not meet the EU requirements on environmentally friendly surfactants. The non-ionic surfactant complex system without alkylphenol polyoxyethylene ether as silicone oil emulsifier was studied in this paper. The experiments were designed and optimized with uniform design software. Under the condition that the quality fraction of emulsifier was 7%, different kinds of non-ionic surfactants were used as emulsifiers to determine the value range of each factor and set an appropriate level within this range. According to factor number and level number, the appropriate uniform design table was selected for factor horizontal data arrangement, and the experimental points in the uniform design table were tested. The obtained experimental data were analyzed by regression analysis, the regression model was established, and the optimized experimental points of the regression equation were verified experimentally. The synergistic effect of surfactants and the effect on the stability of emulsified silicone oil were investigated. The optimal environmentally friendly nonionic silicone oil emulsifier without alkylphenol polyoxyethylene was obtained.

Microcapsules consisting of 58# paraffin wax used as the cores and melamineformaldehyde resin used as the shell were synthesized by the insitu polymerization, and the improvement of apparent morphology and core content of microcapsules was researched. The effects of pH adjustment method, the type of curing agent and stratified treatment on morphology and thermal storage property of microcapsule were studied by SEM, PSDA and DSC. It indicates that pH adjustment is an important factor to microcapsules' morphology and the overall property of microcapsules is greatly improved when NaCl is used as curing agent. After stratified processing, particle sizes of the microcapsules show unimodal distribution and core material content is up to 86.1%.