Yan Liu

In this study, the influence of polyol type and molecular weight on the performance of Waterborne polyurethanes (WPUs) was systematically investigated. WPUs systems modified with long fatty side chains were successfully prepared by innovatively introducing terminal hydroxyl silicone oils to construct a heterostructure and using glycerol monostearate as a functional chain extender. Characterization via FTIR, TGA, SEM, and contact angle testing confirmed that when polytetrahydrofuran ether diol (PTMG) with a molecular weight of 2000 g/mol was selected as the soft segment, the resulting material exhibited significant synergistic effects. Its water contact angle reached 108.7°, and the 72 h water absorption rate was only 10.78% markedly lower than that of WPUs derived from other polyols. Additionally, when the film was heated to 250℃, only 5 wt% decomposed. This material combines excellent hydrophobicity, low water absorption, good thermal stability, and mechanical properties. The significantly enhanced water resistance effectively addresses the application limitations of traditional waterborne coatings in humid environments. It provides a theoretical foundation and process reference for developing high-performance eco-friendly protective coatings, particularly suitable for ship anticorrosion, outdoor building materials, and other harsh weathering applications.

Phase change materials (PCMs) are regarded as highly efficient energy storage media with significant application value in thermal energy management. However, they often face challenges such as leakage, poor thermal conductivity, supercooling, and corrosion in practical applications. To address these challenges, this study employed interfacial polymerization to prepare microencapsulated phase change materials with polyurethane (PU) as the shell and octadecane as the core material (O@PU). These microcapsules were then incorporated, along with graphene, into a waterborne polyurethane (GWPU) emulsion to fabricate a series of composite film materials (GWPU-PCMs) endowed with photothermal conversion and temperature regulation capabilities.This study investigated the effects of core-to-shell ratio on the morphology, thermal properties, and stability of the microcapsules. The results indicated that at a core-to-shell ratio of 1:2, the microcapsules exhibited a regular spherical structure, high phase change enthalpy, and good cycling stability. Observations via transmission electron microscopy (TEM) and scanning electron microscopy (SEM) confirmed that the microcapsules possessed a complete core-shell structure, with the polyurethane shell effectively encapsulating the core material and preventing leakage. Thermogravimetric analysis (TGA) revealed that the main decomposition of the microcapsules occurred within the range of 300–400°C, and the shell structure maintained certain stability at high temperatures. Furthermore, O@PU microcapsules were blended with graphene in a GWPU matrix to prepare composite films with varying PCMs content. Thermal conductivity tests showed that when the PCMs content reached 40%, the thermal conductivity of the composite peaked at 0.25 W·m−1·K−1, representing an approximately 108% improvement compared to pure GWPU. This enhancement was attributed to the construction of a graphene-based thermal conduction network and the synergistic effect of the microcapsules. Photothermal conversion performance tests demonstrated that under simulated sunlight irradiation, the composite exhibited a significant temperature buffering effect. Higher PCMs content resulted in a more pronounced temperature plateau during heating and a slower cooling process, reflecting its intelligent "heat storage-release" regulatory capability. Additionally, infrared thermal imaging and human contact experiments indicated that the composite material exhibited uniform temperature distribution and good thermal comfort in thermal management applications.

In this study, waterborne polyurethane (WPU) microcapsules encapsulating bendiocarb were successfully prepared by interfacial polymerization for sustainable mosquito control. A high encapsulation efficiency of 94% was achieved by systematically optimizing the emulsifier concentration (2% PVA), core-to-wall ratio (1:2), reaction temperature (50°C), and reaction time (6 h). Comprehensive characterization confirmed the uniform spherical morphology (particle size 1–3 µm), core-shell structure, and thermal stability of the microcapsules. Importantly, a core-to-wall ratio threshold of 2:1 was determined: microcapsules with core-to-wall ratios ≤ 2:1 have a dense cross-linked network that provides dual core protection (physical barrier + thermal dissipation; initial decomposition temperature T₀ ≥ 163°C), while ratios > 2:1 lead to shell discontinuities and thermal channeling (T₀ ≤ 145°C), and the protective effect of the walls on the core is lost. Long-term efficacy of the microencapsulated fabrics was demonstrated by bioassays: 27% residual drug retention after 20 washes and the drug residue after 28 days of cumulative release (at a constant temperature of 40°C) was 30.8%. This study establishes an ecologically sound framework for the targeted application of pesticides based on the World Health Organization guidelines on pesticide residues.

In this paper, a string of waterborne polyurethane (WPU) emulsions synergistically modified with PDMS and GMS were successfully prepared by incorporating Polydimethylsiloxane (PDMS) into the soft segments of waterborne polyurethanes, and using glycerol monostearate (GMS) as a chain extender. FTIR, TGA, SEM, particle size test, water contact angle and other tests were used to characterize the effects of variable GMS contents on the structure and function of WPUs. The experimental tests showed that the WPUs synthesised with 30% PDMS-8% GMS synergism had better overall performance. The water contact angle could reach 115.4 °, and the water absorption was reduced to 10.52% at 72 h. Furthermore, this innovative WPU film had excellent thermal stabilization, and this study provided a new approach to improve waterproofing performance, hydrophobicity and thermal stability of waterborne polyurethanes, which is expected to be applied in coatings, adhesives and water-resistant agents.