Phase Change Microcapsule Composite Material with Intelligent Thermoregulation Function for Infrared Camouflage 一种具有智能调温功能的相变微胶囊复合材料用于红外伪装
Ying Su ^(1){ }^{1}, Xiaoming Zhao ^(1,2,3,**){ }^{1,2,3, *} and Yue Han ^(1){ }^{1} 苏英 ^(1){ }^{1} 、赵晓明 ^(1,2,3,**){ }^{1,2,3, *} 和韩玥 ^(1){ }^{1}1 School of Textile Science and Engineering, Tiangong University, Tianjin 300387, China 1 天津300387天津大学纺织科学与工程学院2 Tianjin Key Laboratory of Advanced Textile Composites, Tiangong University, Tianjin 300387, China 2 天津市先进纺织复合材料天津市重点实验室,天津3003873 Tianjin Municipal Key Laboratory of Advanced Fiber and Energy Storage, Tiangong University, Tianjin 300387, China 3 天津市先进纤维与储能天津市重点实验室,天津300387* Correspondence: texzhao@163.com * 对应方式:texzhao@163.com
Citation: Su, Y.; Zhao, X.; Han, Y. Phase Change Microcapsule Composite Material with Intelligent Thermoregulation Function for Infrared Camouflage. Polymers 2023, 15,3055. https://doi.org/ 10.3390/polym15143055 引自:Su, Y.;赵 X.;Han, Y. 具有红外伪装智能温度调节功能的相变微胶囊复合材料。聚合物 2023, 15,3055。https://doi.org/ 10.3390/polym15143055
Academic Editors: Jiangtao Xu and Sihang Zhang 学术编辑:徐江涛、张思航
Received: 19 June 2023 收稿日期: 2023-06-19
Revised: 9 July 2023 修订日期:2023 年 7 月 9 日
Accepted: 14 July 2023 录用日期: 2023-07-14
Published: 15 July 2023 发布日期:2023 年 7 月 15 日
The infrared camouflage textile materials with soft and wear-resistant properties can effectively reduce the possibility of soldiers and military equipment being exposed to infrared detectors. In this paper, the infrared camouflage textile composites with intelligent temperature adjustment ability were prepared by different methods, using phase change microcapsule as the main raw material and high polymer polyurethane as the matrix, combining the two factors of temperature control and emissivity reduction. It was tested by differential scanning calorimeter, temperature change tester, infrared emissivity tester, and infrared imager. The results show that the temperature regulation effect of textile materials finished by coating method is better than dip rolling method, the temperature regulation ability and presentation effect are the best when the microcapsule content is 27%27 \%. When the bottom layer of infrared camouflage textile composite is 27%27 \% phase change microcapsule and the surface layer is 20%20 \% copper powder, its infrared emissivity in the band of 2-22 mum2-22 \mu \mathrm{~m} is 0.656 , and the rate of heating and cooling is obviously slowed down. It has excellent heat storage and temperature regulation function, which can reduce the skin surface temperature by more than 6^(@)C6^{\circ} \mathrm{C} and effectively reduce the infrared radiation. This study can provide reference for laboratory preparation and industrial production of infrared camouflage composite material. The infrared camouflage textile composite prepared are expected to be used in the field of military textiles. 具有柔软耐磨性能的红外迷彩纺织材料可以有效降低士兵和军事装备暴露在红外探测器下的可能性。本文以相变微胶囊为主要原料,以高分子聚氨酯为基体,结合控温和降低发射率两个因素,通过不同方法制备了具有智能温度调节能力的红外伪装纺织复合材料。通过差示扫描量热仪、温度变化测试仪、红外发射率测试仪和红外成像仪进行了测试。结果表明:涂层法整理的纺织材料温度调节效果优于浸渍轧制法,当微胶囊含量 . 27%27 \% 当红外伪装纺织复合材料的底层为 27%27 \% 相变微胶囊,表层为 20%20 \% 铜粉时,其波段内的红外发射率 2-22 mum2-22 \mu \mathrm{~m} 为0.656,加热和冷却的速度明显减慢。具有优良的蓄热和温度调节功能,可使皮肤表面温度降低以上 6^(@)C6^{\circ} \mathrm{C} ,有效减少红外辐射。本研究可为红外伪装复合材料的实验室制备和工业生产提供参考。制备的红外迷彩纺织复合材料有望应用于军用纺织品领域。
Matter is generally divided into three phases: solid, liquid, and gas. The transition between different phase states of the same material is called phase transition [1]. The substance whose state can be changed is called phase change material (PCM). When the phase change occurs, there is a significant energy exchange between the material and the environment, which will be strongly coupled with the heat transfer, so that the material has a certain temperature control and heat release function [2,3]. With this capability of phase change materials, the temperature around the working source or materials can be adjusted and controlled to reduce the mismatch between energy supply and demand in time and speed [4]. Therefore, phase change materials are applied broadly in the field of energy storage and temperature regulation [5,6]. However, phase change materials have problems such as large volume changes, easy leakage, and low thermal conductivity. Microencapsulation of phase change materials is an advanced application method. Microcapsule phase change material (MPCM), also known as phase change microcapsule, is a new type of composite phase change material with core-shell structure. It is coated with a stable polymer film on the surface of solid-liquid phase change material particles. 物质通常分为三个相:固体、液体和气体。同一材料的不同相态之间的转变称为相变 [1]。状态可以改变的物质称为相变材料 (PCM)。当相变发生时,材料与环境之间存在显着的能量交换,这种交换将与传热强耦合,使材料具有一定的温度控制和热释放功能 [2,3]。借助相变材料的这种能力,可以调整和控制工作源或材料周围的温度,以减少能源供需在时间和速度上的不匹配 [4]。因此,相变材料在储能和温度调节领域得到了广泛的应用[5,6]。然而,相变材料存在体积变化大、易泄漏、导热系数低等问题。相变材料的微胶囊化是一种先进的应用方法。微胶囊相变材料(MPCM),又称相变微胶囊,是一种具有核壳结构的新型复合相变材料。它在固液相变材料颗粒表面涂有一层稳定的聚合物膜。
The shell structure of microcapsules can provide good protection for phase change core materials, improve the stability of phase change materials, prevent chemical reactions with the outside world and leakage during long-term cyclic use, and significantly increase the contact area with the matrix material to improve thermal conductivity, thereby improving the working performance of phase change materials [7-9]. When the external temperature changes, the core material in the microcapsule will undergo phase change. The phase change material absorbs or releases a large amount of heat, and the temperature of the microcapsule itself remains constant, to achieve the effect of intelligent temperature regulation [10-13]. Phase change microcapsules with temperature regulation ability are widely used in construction [14-18], solar energy [19], food industry [20], textile [21,22], and other fields 微胶囊的壳结构可以为相变核心材料提供良好的保护,提高相变材料的稳定性,防止与外界发生化学反应和长期循环使用时的泄漏,并显著增加与基体材料的接触面积,提高导热系数,从而提高相变材料的工作性能[7-9]。当外部温度发生变化时,微胶囊中的芯材会发生相变。相变材料吸收或释放大量热量,微胶囊本身的温度保持恒定,达到智能调温的效果[10-13]。具有温度调节能力的相变微胶囊广泛应用于建筑[14-18]、太阳能[19]、食品工业[20]、纺织[21,22]等领域
In the modern battlefield, the infrared radiation energy of general military targets is higher than the background, so it is easy to find out by using infrared detectors. According to Stefan Boltzmann’s Law (1) [23], the total infrared radiation energy of an object is directly proportional to the fourth power of its emissivity and absolute temperature. Therefore, the possibility of the target being discovered by the infrared detector can be reduced by reducing the emissivity and controlling the temperature, to achieve its camouflage effect in the infrared band. Therefore, infrared camouflage materials that protect military targets without changing the shape and structure of the target have attracted extensive attention in the national defense and military industry [24]. Various infrared camouflage materials developed around fibers and fiber products are called infrared camouflage textile materials. Infrared camouflage textile materials are soft, portable, and wearable. They are the main raw materials of infrared camouflage clothing, backpacks, camouflage nets and tents. They can provide guarantee for the survival of soldiers and weapons and equipment, and plays an extremely important role in the battlefield [25,26]. In terms of reducing infrared emissivity, it mainly includes developing new low emissivity fibers [27-30], modifying existing fibers [31-33] or coating low infrared emissivity coatings [34-36]. In terms of temperature control, in addition to thermal insulation and structural design [37-40], the temperature regulating textile [41-44] and infrared camouflage textile [45-47] are prepared by combining phase change microcapsules with textile, which can effectively reduce the infrared radiation energy of the target [48-50]. However, it is difficult to use phase change microcapsules for infrared camouflage alone. Its phase change temperature, latent heat of phase change, and thermal conductivity can hardly meet the requirements of thermal camouflage. Only by combining with other functional materials can infrared camouflage be better realized [51]. According to Kirchhoff’s law, opaque objects with high reflectivity generally have low emissivity. Metal is a typical low-emissivity material, which is generally used in the field of infrared camouflage in the form of coating. Among them, copper and aluminum have become the main force of metal fillers due to their low cost and easy availability, excellent performance, and wide application. In this paper, phase change microcapsules are finished on the fabric, and the temperature-regulated fabric is obtained by changing different parameters. On this basis, the infrared camouflage fabric was prepared by adding low emissivity materials. Then its temperature adjustment ability, infrared camouflage effect, and mechanism are analyzed systematically. Compared with the untreated fabric, the prepared textile has a certain degree of infrared camouflage ability, which can delay the speed of temperature rise and effectively reduce the infrared thermal radiation. 在现代战场中,一般军事目标的红外辐射能量高于背景,因此使用红外探测器很容易发现。根据斯特凡·玻尔兹曼定律 (1) [23],物体的总红外辐射能量与其发射率和绝对温度的四次方成正比。因此,可以通过降低发射率和控制温度来降低目标被红外探测器发现的可能性,从而在红外波段达到其伪装效果。因此,在不改变目标形状和结构的情况下保护军事目标的红外伪装材料在国防和军工工业中引起了广泛关注 [24]。围绕纤维和纤维制品开发的各种红外伪装材料称为红外伪装纺织材料。红外迷彩纺织材料柔软、便携、耐磨。它们是红外迷彩服、背包、迷彩网和帐篷的主要原材料。它们可以为士兵的生存和武器装备提供保障,在战场上发挥着极其重要的作用[25,26]。在降低红外发射率方面,主要包括开发新的低发射率光纤[27-30]、改性现有光纤[31-33]或涂覆低红外发射率涂层[34-36]。在温度控制方面,除了保温和结构设计[37-40]外,通过将相变微胶囊与纺织品相结合,制备了调温纺织品[41-44]和红外迷彩纺织品[45-47],可有效降低目标的红外辐射能量[48-50]。 然而,单独使用相变微胶囊进行红外伪装是困难的。它的相变温度、相变潜热和导热系数很难满足热伪装的要求。只有与其他功能材料结合,才能更好地实现红外伪装 [51]。根据基尔霍夫定律,具有高反射率的不透明物体通常具有低发射率。金属是一种典型的低辐射率材料,一般以涂层的形式用于红外伪装领域。其中,铜和铝因其成本低廉、易得、性能优良、应用广泛而成为金属填料的主力军。在本文中,在织物上完成相变微胶囊,并通过改变不同的参数获得温度调节织物。在此基础上,通过添加低发射率材料制备了红外迷彩织物。然后,系统分析了其温度调节能力、红外伪装效果和机理。与未经处理的织物相比,制备的织物具有一定的红外伪装能力,可以延缓升温的速度,有效减少红外热辐射。
E=sigma epsiT^(4)E=\sigma \varepsilon T^{4}
where EE is the infrared radiation (J//(s*m^(2))),sigma\left(\mathrm{J} /\left(\mathrm{s} \cdot \mathrm{m}^{2}\right)\right), \sigma is Stefan Boltzmann constant, epsi\varepsilon is the emissivity of the target surface, and TT is the thermodynamic temperature of the target surface (K). 其中 EE 是红外辐射 (J//(s*m^(2))),sigma\left(\mathrm{J} /\left(\mathrm{s} \cdot \mathrm{m}^{2}\right)\right), \sigma 是斯特凡·玻尔兹曼常数, epsi\varepsilon 是目标表面的发射率, TT 是目标表面的热力学温度 (K)。
2. Materials and Methods 2. 材料和方法
2.1. Materials 2.1. 材料
The fabric used in the experiment was cotton fabric, which was purchased from Hongfei Textile Manufacturing, Baoding, China. Phase change microcapsules are prepared 实验中使用的面料是棉织物,购自中国保定市鸿飞纺织制造有限公司。制备相变微胶囊
by in-situ polymerization with paraffin as core material and urea-formaldehyde resin as wall material. Urea and formaldehyde aqueous solutions were purchased from Meryer (Shanghai) Chemical Technology, Shanghai, China. Paraffin, OP emulsifier, triethanolamine, citric acid and petroleum ether were purchased from Beijing enokai Technology, Beijing, China. Polyurethane resin was purchased from Guangzhou Yuheng environmental protection materials, China. Hollow glass beads were purchased from Henan Bairun casting materials, Zhengzhou, China. Silicon dioxide was purchased from Jiangsu Tianxing’s new materials, Huaian, China. The copper powder was purchased from Nangong Xindun alloy welding material spraying, Xingtai, China. Aluminum powder was purchased from Shanghai Aladdin Biochemical Technology, Shanghai, China. All reagents were of analytical grade and used directly without further purification. The details are shown in Table 1. 以石蜡为芯材,脲醛树脂为壁材的原位聚合。尿素和甲醛水溶液购自中国上海的 Meryer (Shanghai) Chemical Technology。石蜡、OP 乳化剂、三乙醇胺、柠檬酸和石油醚购自中国北京 Enokai Technology。聚氨酯树脂购自中国广州禹衡环保材料有限公司。空心玻璃珠购自中国郑州的河南百润铸造材料公司。二氧化硅购自中国淮安的江苏天兴新材料公司。铜粉购自中国邢台市南工欣盾合金焊接材料喷涂有限公司。铝粉购自中国上海上海阿拉丁生化科技公司。所有试剂均为分析级试剂,无需进一步纯化即可直接使用。详细信息如表 1 所示。
Table 1. Material Information. 表 1.材料信息。
Material 材料
Particle Size/Model 粒径/型号
Manufacturer 制造者
Hollow glass beads 空心玻璃珠
30-100 mum30-100 \mu \mathrm{~m}
Henan Bairun casting materials, China 中国河南百润铸造材料
Silicon dioxide 二氧化硅
20 nm 20 纳米
Jiangsu Tian xing's new materials, China 中国江苏天兴新材料
Shanghai Aladdin Bio-chemical Technology, China 上海阿拉丁生化技术有限公司
Polyurethane 聚氨酯
PU2540
Guangzhou Yuheng environmental protection materials, China 广州禹衡环保材料有限公司,中国
Defoamer 消 泡 剂
AFE-1410
Shandong Yousuo Chemical Technology, China 山东优索化工科技,中国
Thickener 增 稠 剂
7011
Guangzhou Dianmu Composite Materials Business Department, China 中国广州电木复合材料业务部
Dispersant 分散 剂
5040
Shandong Yousuo Chemical Technology, China 山东优索化工科技,中国
Meryer (Shanghai) Chemical Technology, China Meryer (Shanghai) Chemical Technology, 中国
Urea, Formaldehyde aqueous solutions 尿素、甲醛水溶液
Beijing enokai Technology, China 北京 enokai Technology, 中国
Paraffin, OP emulsifier, Triethanolamine, 石蜡、OP 乳化剂、三乙醇胺、
Citric acid, Petroleum ether 柠檬酸、石油醚
Material Particle Size/Model Manufacturer
Hollow glass beads 30-100 mum Henan Bairun casting materials, China
Silicon dioxide 20 nm Jiangsu Tian xing's new materials, China
Copper powder 38 mum Nangong Xindun alloy welding mate-rial spraying, China
Aluminum powder 25 mum Shanghai Aladdin Bio-chemical Technology, China
Polyurethane PU2540 Guangzhou Yuheng environmental protection materials, China
Defoamer AFE-1410 Shandong Yousuo Chemical Technology, China
Thickener 7011 Guangzhou Dianmu Composite Materials Business Department, China
Dispersant 5040 Shandong Yousuo Chemical Technology, China
Meryer (Shanghai) Chemical Technology, China
Urea, Formaldehyde aqueous solutions Beijing enokai Technology, China
Paraffin, OP emulsifier, Triethanolamine,
Citric acid, Petroleum ether | Material | Particle Size/Model | Manufacturer |
| :---: | :---: | :---: |
| Hollow glass beads | $30-100 \mu \mathrm{~m}$ | Henan Bairun casting materials, China |
| Silicon dioxide | 20 nm | Jiangsu Tian xing's new materials, China |
| Copper powder | $38 \mu \mathrm{~m}$ | Nangong Xindun alloy welding mate-rial spraying, China |
| Aluminum powder | $25 \mu \mathrm{~m}$ | Shanghai Aladdin Bio-chemical Technology, China |
| Polyurethane | PU2540 | Guangzhou Yuheng environmental protection materials, China |
| Defoamer | AFE-1410 | Shandong Yousuo Chemical Technology, China |
| Thickener | 7011 | Guangzhou Dianmu Composite Materials Business Department, China |
| Dispersant | 5040 | Shandong Yousuo Chemical Technology, China |
| Meryer (Shanghai) Chemical Technology, China | | |
| Urea, Formaldehyde aqueous solutions | | Beijing enokai Technology, China |
| Paraffin, OP emulsifier, Triethanolamine, | | |
| Citric acid, Petroleum ether | | |
2.2. Methods 2.2. 方法
2.2.1. Preparation of Phase Change Microcapsules 2.2.1. 相变微胶囊的制备
Mix urea and formaldehyde aqueous solution in a certain proportion, drop triethanolamine to adjust the pH value of the solution to be weakly alkaline, react at 70^(@)C70{ }^{\circ} \mathrm{C} for 1 h , and add deionized water to form a stable urea/formaldehyde prepolymer solution. Add a certain amount of OP emulsifier and paraffin into deionized water, heat and melt, emulsify and disperse for 30min(3000r//min)30 \mathrm{~min}(3000 \mathrm{r} / \mathrm{min}) at 60^(@)C60^{\circ} \mathrm{C}, and form a stable emulsion. Drop the prepolymer solution into the emulsion and stir for 20 min after dropping. Then slowly add citric acid solution, adjust the final pH value of the solution to be acidic, keep the temperature at 60^(@)C60^{\circ} \mathrm{C} for reaction for 1 h , and then raise the temperature to 90^(@)C90^{\circ} \mathrm{C}, and keep the temperature for reaction for 2 h . After the reaction, the microcapsule lotion was poured out, cooled, separated and filtered. The obtained microcapsules were washed twice with petroleum ether and deionized water, and dried to obtain white powder microcapsules. 将尿素和甲醛水溶液按一定比例混合,滴加三乙醇胺调节溶液的pH值呈弱碱性,反应 70^(@)C70{ }^{\circ} \mathrm{C} 1 h,加入去离子水,形成稳定的尿素/甲醛预聚物溶液。在去离子水中加入一定量的OP乳化剂和石蜡,加热熔融,乳化分散, 30min(3000r//min)30 \mathrm{~min}(3000 \mathrm{r} / \mathrm{min})60^(@)C60^{\circ} \mathrm{C} 形成稳定的乳液。将预聚物溶液滴入乳液中,滴加后搅拌 20 分钟。然后缓慢加入柠檬酸溶液,将溶液的最终pH值调节为酸性,保持反应温度1 60^(@)C60^{\circ} \mathrm{C} h,然后升温至 90^(@)C90^{\circ} \mathrm{C} ,保持反应温度2 h。反应结束后,将微胶囊化妆水倒出,冷却,分离,过滤。所得微胶囊用石油醚和去离子水洗涤两次,干燥,得白色粉末微胶囊。
2.2.2. Preparation of Phase Change Microcapsule Temperature Regulating Textile by Dip Rolling 2.2.2. 浸轧制备相变微胶囊调温纺织品
Disperse the phase change microcapsule particles in water, add dispersant, adhesive, and penetrant, mix evenly to obtain the phase change microcapsule solution. The cotton fabric with 10 xx10cm^(2)10 \times 10 \mathrm{~cm}^{2} was washed and dried. Put it into a beaker containing phase change microcapsule solution and fully wet it, with a bath ratio of 1:20. The phase change microcapsule fabric was obtained by two dipping and two rolling processes, drying at 80^(@)C80^{\circ} \mathrm{C} for 5 min , and then baking at 120^(@)C120^{\circ} \mathrm{C} for 2 min . Two groups of phase change microcapsule fabrics were prepared by changing the microcapsule content and adhesive content respectively. 将相变微胶囊颗粒分散在水中,加入分散剂、胶粘剂和渗透剂,混合均匀,得到相变微胶囊溶液。棉 10 xx10cm^(2)10 \times 10 \mathrm{~cm}^{2} 布经过洗涤和干燥。将其放入盛有相变微胶囊溶液的烧杯中,充分润湿,浴比为 1:20。相变微胶囊织物经两次浸渍和两次轧制工艺得到,干燥 80^(@)C80^{\circ} \mathrm{C} 5 min,然后烘烤 120^(@)C120^{\circ} \mathrm{C} 2 min。通过改变微胶囊含量和胶粘剂含量,制备了两组相变微胶囊织物。
2.2.3. Preparation of Phase Change Microcapsule Temperature Regulating Textile by Coating Method 2.2.3. 涂布法制备相变微胶囊调温纺织品
Disperse the phase change microcapsule particles in water, add adhesive, thickener, dispersant and defoamer, and stir evenly to obtain phase change microcapsule coating. 将相变微胶囊颗粒分散在水中,加入胶粘剂、增稠剂、分散剂和消泡剂,搅拌均匀,得到相变微胶囊包衣。