二十烷/膨胀石墨复合相变材料的制备及其对卷烟滤嘴温度的调控

Preparation of eicosane/expanded graphite composite phase change material and its role in cigarette filter temperature control during smoking

为了调控卷烟燃吸过程中滤嘴的温度,以二十烷(Eicosane)为相变材料、膨胀石墨(EG)为基体,运用毛细吸附法制备了二十烷/膨胀石墨(EI/EG)复合相变材料,并将所制备的复合相变材料添加于卷烟滤嘴中,考察卷烟燃吸过程中复合相变材料对滤嘴温度的调控作用。采用差示扫描(DSC)、导热系数、扫描电镜(SEM)、X射线衍射(XRD)、傅里叶红外光谱(FT-IR)、氮气吸脱附技术等对复合相变材料的相变热性能和物化结构进行了表征分析;采用卷烟燃吸温度检测系统检测卷烟燃吸过程中的滤嘴温度数据,并运用温度场温度分布和体积平均温度对滤嘴检测区域温度分布特征进行表征分析。结果表明:1当二十烷含量为92%(质量分数)时,二十烷在膨胀石墨内吸附饱和,相变温度为40.2℃,相变焓为162.9 J/g,导热系数为1.304 W/(m·K),所得EI/EG复合相变材料具有优良的相变热性能及导热性能;2二十烷和膨胀石墨之间属于物理复合,没有形成新的物质,这有利于保持各材料组分自身的属性;3当92%EI/EG复合相变材料在卷烟滤嘴中的添加量为40 mg/支时,在ISO抽吸模式下可将卷烟燃吸过程中的滤嘴温度降至30℃以下,并获得均匀的温度分布,实现滤嘴温度的有效调控。

For controlling the temperature in cigarette filter, an eicosane/expanded graphite（EI/EG） composite phase change material was prepared with capillary adsorption method, wherein eicosane was used as phase change material and graphite as carrier material. The prepared material was added into cigarette filter, the effect of its addition on temperature distribution in cigarette filter was investigated during smoking. The physical-chemical structure and thermal properties of the composite phase change material were characterized by DSC, thermal conductivity coefficient detector, SEM, XRD, FT-IR, and nitrogen adsorption-desorption. Thetemperature distribution in filter was detected by the cigarette combustion temperature detection system and characterized with temperature distribution in the temperature field and mean volumetric temperature. The results showed that： 1） At the content of 92%（mass concentration）, eicosane in expanded graphite approached to adsorptive saturation with the phase transition temperature of 40.2 ℃, phase change enthalpy was of 162.9J/g, and the thermal conductivity of 1.304 W/（m·K）; the prepared eicosane/expansion graphite material had high latent heat and excellent thermal conductivity. 2） In the prepared material, eicosane was physically composited with expanded graphite, the attribute of basic material kept unchanged. 3） When adding 40 mg of92% EI/EG phase change material into a cigarette filter, the temperature in filter decreased to below 30 ℃during smoking under ISO regime, the temperature distribution in filter was uniform, it indicated that the temperature in filter was effectively controlled by the material.