竹纤维基日间被动辐射制冷膜的制备与性能

Preparation of a bamboo fiber-based film for passive daytime radiative cooling and its properties

为缓解高温天气带来的负面影响,可采用经济节能的冷却材料。以天然竹为原料,采用两步法进行脱木质素处理,通过喷涂法引入SiO_(2)粒子,并根据纤维素和SiO_(2)粒子的多级结构和辐射特性,制备具有日间被动辐射制冷性能的降温材料竹纤维/SiO_(2)复合膜;对竹纤维/SiO_(2)复合膜进行结构表征,探究其光谱特性及降温性能。结果表明:SiO_(2)成功引入竹纤维膜中;与原竹相比,竹纤维/SiO_(2)复合膜的太阳光反射率提高至90.1%;竹纤维/SiO_(2)复合膜在大气窗口范围内的红外发射率约97.9%;在户外条件下,辐照强度为546 mW/cm~2时,竹纤维/SiO_(2)复合膜与原竹相比可降低温度约7.8℃,红外热成像也证明竹纤维/SiO_(2)复合膜具有良好的降温性能。该竹纤维/SiO_(2)复合膜有较好的降温效果,具有较大应用潜力。

Economical and energy-saving cooling materials can be used to alleviate the negative impact of hot weather.Natural bamboo was delignified by two-step method,and SiO_(2) particles were introduced by spraying method.Based on the multiscale structure and natural radiation characteristics of cellulose and SiO_(2) particles,a cooling material bamboo fiber/SiO_(2) composite film with passive daytime radiative cooling(PDRC)performance was prepared.The structure of bamboo fiber/SiO_(2) composite film was characterized.Meanwhile,the spectral properties and cooling performance were explored.The results showed that SiO_(2) was successfully introduced into the bamboo fiber film.Compared with the raw bamboo,the solar reflectivity of bamboo fiber/SiO_(2) composite film was significantly improved and reached to 90.1%.The infrared emissivity of bamboo fiber/SiO_(2) composite film in the atmospheric window was about 97.9%.Under a real outdoor environment,when the irradiation intensity was 546 mW/cm~2,the temperature of the bamboo fiber/SiO_(2) composite film was 7.8℃lower than that of the raw bamboo.Infrared thermal imaging also proves that the bamboo fiber/SiO_(2) composite film has good cooling performance.To sum up,the bamboo fiber/SiO_(2) composite film has good cooling effect and great potential for application.