基于静止空气热阻增强机制的新型保温材料研究进展OA

In cold environments,the human body relies on increasing clothing thickness or using HVAC systems to maintain thermal comfort.However,the former is bulky and inconvenient,while the latter exacerbates energy consumption and global warming.Thus,developing new thermal insulation textiles with personal thermal management functions holds significant importance.Centered on the thermal resistance enhancement mechanism of static air,this study aims to systematically sort out the design concepts,preparation methods,structural characteristics,and thermal insulation principles of new passive thermal insulation materials based on fibers,fiber aggregates,and finished garments,so as to provide theoretical support and design references for the development of high-performance thermal insulation materials. During the research,a systematic analysis was conducted following the hierarchy of"fibers-fiber aggregates-finished garments."At the fiber level,the focus was on thermal fibers with single hollow structures,porous structures,and hierarchical porous structures.Among natural fibers,kapok,calotropis gigantea,and milkweed fibers achieve excellent thermal insulation through high hollowness;chemical fibers are modified to form hollow structures(such as hollow polyester and hollow viscose),and bionic porous fibers and hierarchical porous fibers are prepared via freeze-spinning,wet-spinning,electrospinning,and other technologies to optimize static air storage capacity.At the fiber aggregate level,five types of materials—yarns,fabrics,waddings,aerogels,and sponges—are covered.Thermal insulation is enhanced by increasing hollowness and porosity,optimizing internal structures(e.g.,3D spacing and layered porosity),while addressing issues such as structural collapse and insufficient mechanical properties.At the finished garment level,there are mainly two types:inflatable temperature-regulating clothing and shape-memory temperature-regulating clothing.The former adjusts thermal insulation by inflating to change air chamber thickness,while the latter utilizes the environmental responsiveness of shape-memory materials to form air layers,achieving dynamic temperature regulation. The study adopted a combination of literature review,structural characterization,and performance testing to systematically analyze the impact of the micro∕macro structures of different materials on thermal insulation performance.By comparing the effects of various preparation processes(e.g.,freeze-spinning vs.wet-spinning)and structural parameters(e.g.,pore size and hollowness)on key indicators such as thermal conductivity and thermal resistance of textiles,optimal strategies for improving thermal insulation performance at each hierarchical level were derived.The results show that fiber diameter and porous structure,the bulkiness and structural design of aggregates,and the static air content inside garments are the core influencing factors for the thermal insulation performance of materials at each level.Hierarchical porous structures,nano-scale fibers,and composite modification technologies can significantly improve material insulation efficiency—for instance,gradient nanostructured aramid aerogel fibers have a thermal conductivity as low as 0.022 8 W∕(m·K);inflatable temperature-regulating clothing has a thermal resistance 14-15 times higher than ordinary fabrics,and shape-memory materials can form air layers up to 18 mm thick,effectively enhancing thermal insulation.It is found that constructing air layers to enhance thermal resistance is the core strategy for improving thermal insulation performance:material structures have evolved from hollow fiber structures to hierarchical porous structures,scales have advanced from micro to nano ones,and preparation technologies have become more diversified and precise.The innovations of this study lie in three aspects:first,establishing a"structure-performance"correlation system to clarify the key roles of static air storage and heat transfer path blocking;second,systematically analyzing the preparation methods of hollowed natural fibers,bionic porous fibers,and multi-scale thermal insulation aggregates;third,introducing simulation techniques(such as CFD fluid dynamics analysis)into the research,providing new insights into the internal temperature regulation mechanism of textiles. Future research on new thermal insulation materials will focus on the following areas:first,using software simulation technologies to deeply explore the internal heat transfer mechanisms and surface air flow characteristics of materials,so as to provide theoretical support for material structure optimization;second,improving the wash resistance and mechanical properties of thermal insulation materials to further enhance their practical wearability and application scenarios;third,enriching the diversification of garment components such as shape-memory materials,optimizing wearability and environmental response accuracy,and realizing the design of thermal insulation clothing with high comfort,precision and durability.