A waterborne polyurethane (WPU) prepolymer was synthesized with poly(tetramethylene glycol) to form the soft segment, dimethylolpropionic acid as a hydrophilic chain extender, and isophorone diisocyanate. Moreover, the graft and block copolymer emulsification of WPU-polysiloxane and their films was carried out through reactions between the WPU prepolymer, aminoethyl aminopropyl dimethicone (AEAPS), and a linear polyether-blocked amino silicone (LEPS), respectively. The properties of the structure and formed films of the WPU were characterized with Fourier transform infrared spectrometry, gel permeation chromatography, X-ray diffraction, thermogravimetric analysis, dynamic thermomechanical analysis, and X-ray photoelectron spectroscopy; the measurement of the water contact angle; the testing of the water absorption; and so on. The WPU-polysiloxane emulsion showed a high stability, and the molecular weight of WPU increased. Moreover, the glass-transition temperature (T g ) of the soft segment of polysiloxane that was incorporated into the WPU shifted to a lower temperature range, whereas the T g of the hard segment shifted to a higher temperature range, and the crystallinity of the WPU-polysiloxane film was reduced. There was a greater degree of crosslinking and accumulation of polysiloxane segments on the surface of the WPU emulsion that was modified with AEAPS in comparison to the LEPS-modified WPU emulsion. Therefore, the water resistance of the AEAPS-modified WPU was higher than that of the LEPS-modified WPU. The rigidity and elasticity of the WPU-polysiloxane film improved, whereas its tensile strength did not change much after AEAPS was used. However, this was not true after LEPS was used, as the tensile strength decreased significantly. Nevertheless, the flexibility and plasticity of the WPU-polysiloxane film were enhanced after LEPS was used.

In the preparation of microencapsulated phase change materials (MicroPCMs) with a three-composition shell through interfacial polymerization, the particle size, phase change behaviors, core contents, encapsulation efficiency morphology, thermal stability and chemical structure were investigated. The compactness of the MicroPCMs was analyzed through high-temperature drying and weighing. The effect of the core/shell ratio and stirring rate of the system was studied. The results indicated that the microcapsules thus-obtained possessed a spherical shape and high thermal stability and the surfaces were intact and compact. Furthermore, in the emulsification stage, the stirring speed had a significant influence on the microcapsules’ particle size, and smaller particles could be obtained under the higher stirring speed, and the distributions were more uniform in these cases. When the core/shell ratio was lower than 4, both the core content and the encapsulation efficiency was high. Additionally, when the core/shell ratio was higher than 4, the encapsulation efficiency was decreased significantly. The three-composition shell greatly increased the compactness of microcapsules, and when the core/shell ratio was adjusted to 3, the mass loss of the MicroPCMs was lower than 6% after drying at 120 °C for 1 h. After the microencapsulation, double exothermic peaks appeared on the crystallization curve of the MicroPCMs, the crystallization mechanism was changed from the heterogeneous nucleation to the homogeneous nucleation and the super cooling degree was enhanced.

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Porous poly(vinyl alcohol) (PVA)/phase change microcapsule composites with shape memory properties were prepared by physical foaming, cycles of freezing-thawing and freeze drying. The effects of phase change microcapsules on pore structure, phase change energy storage capacity, thermal stability, crystallinity, mechanical properties, shape memory properties and water absorption and retention of the porous composites were investigated. With an increase of the proportion of phase change microcapsules, the pore density, pore size and water absorption and retention of the porous composite materials were decreased, while the phase change energy storage performance was improved and ΔH m was up to 31.22 J g −1 . The phase change energy storage of the porous composites was stable even after 50 phase transition cycles. Meanwhile, the thermal stability of the porous composites was also not affected by the addition of phase change microcapsules. The entanglement of PVA molecular chains in the porous composites was affected by the microcapsules embedded in the matrix of PVA during freezingthawing cycles, resulting in a change of crystallinity and mechanical properties of the porous composites. The porous composites with phase change energy storage capacity also showed good shape memory performance with shape recovery rate of 100% even after multiple deformation, which was expected to expand the multi-field application of dual-functional materials.