论文题目：多孔基导热定型复合相变材料的制备及性能研究

毕业学生：刘志红

指导教师：吴唯

中文摘要：

目前，PCMs已广泛应用于余热回收、热能输送、阳能利用等众多热能存储管理系统。然而，广泛使用的有机相变材料，在使用时通常存在易泄漏、体积变化，导热率较低，以及必须使用特殊的潜热装置等问题，极大地限制其实际应用。因此，制备形态稳定、导热率高 的复合相变材料具 有十分重要的价值。

以回收聚苯乙烯泡沫为原料，采用Scholl偶联法合成超交联聚合物HCFoam-Al，通过不同催化剂用量来调整比表面、孔径，实现增大孔体积的目的，采用真空浸渍法对相变材料棕榈酸，1-十八烷醇和固体石蜡包封固载，筛选出效果最佳时AlCl₃与PS用量为8：1，HCFoam-Al和PCMs的吸附比为6：1。三种复合材料的潜热分别为145.06 J g-1、132.30 J g-1、116.82 J g-1。PA/HCFoam-Al经过100次循环后显示出优良的热可循环性，负载率只下降了1.42 wt%，且导热系数较纯PA提高了12.59 %。

采用外交联剂FDA与芳环发生Friedel-Crafts反应，改善聚合物的交联度，研究PS与FDA用量比对超交联聚合物HCFoam-Fe比表面、孔体积和孔径尺寸的影响，结果表明，随着FDA用量的增加，样品的孔隙结构更完善，比表面、孔体积和孔径尺寸整体呈现增大趋势，最佳分别为1097 m² g^-1、0.96 m³g^-1、3.4 nm。以其为载体，三种复合材料的潜热分别为145.06 J g-1、132.30 J g-1、116.82 J g-1。此外，HCFoam-Fe的加入对相变木材料的导热 率有一定的改善作用。

为进一步提高复合材料的导热率，以HCFoam-Fe4为模板，高温碳化制备了多孔碳4C，研究了碳化温度对4C多孔结构的影响，结果表明，随着温度的升高，4C比表面积，总孔体积呈现增大趋势，孔径 分布更广。最佳工艺参数为：温度800 ^oC，表面积和总孔体积2532 m² g^-1、1.86 cm³ g^-1。DSC测试结果表明，PA、SA、PW在4C-800上的负载率分别为79.93 wt%，81.90 wt%和79.45 wt%。此外，PA/4C的导热率表现出先增 大后减小的趋势，负载率最高的PA/4C-800导热率为0.502 W m^-1 k^-1，较纯PA和PA/HCFoam-Fe4分别有70.75 %和57.86 %的提高。

  Abstract:

At present, PCMs have been widely used in many thermal energy storage and management systems, such as waste heat recovery, heat energy transmission, solar energy utilization and so on. However, the widely used organic phase change materials usually have some problems, such as easy leakage, volume change, low thermal conductivity, and the need to use special latent heat devices, which greatly limit their practical application. Therefore, the preparation of phase change materials with stable morphology and high thermal conductivity is of great value.

In the first part of the project, HCFoam-Al (Foam-based Hypercrosslinked polymer) was synthesized by Scholl coupling method using recycled polystyrene foam as raw material. Adjust the specific surface, pore size and the pore volume by changing the amount of catalyst (AlCl₃). Vacuum impregnation method was used to encapsulate phase change material palmitic acid (PA), Stearyl alcohol (SA) and Paraffin wax (PW). The optimum concentration of AlCl₃ and PS was 8:1, and the adsorption ratio of HCFoam-Al and PCMs was 6:1. The latent heat of the three composites were 145.06 J g^-1, 132.30 J g^-1 and 116.82 J g^-1, respectively. The PA/HCFoam-Al with the best adsorption performance showed excellent thermal cycleability after 100 cycles, the load rate decreased by only 1.4 wt%, and the thermal conductivity increased by 12.59% compared with pure PA.

In the second part, Friedel-Crafts reaction between FDA and aromatic rings was used to improve the crosslinking degree of polymers. The effects of the dosage ratio of PS to FDA on the specific surface, pore volume and pore size of HCFoam-Fe were studied. The results show that with the increase of FDA dosage, the pore structure of the samples was more perfect, and the specific surface, pore volume and pore size of the samples show an overall increasing trend. The optimum parameters were 1097 m² g^-1, 0.96 m³ g^-1 and 3.4 nm, respectively. With it as the carrier, the latent heat of the three composite materials were 145.06 J g^-1, 132.30 J g^-1, and 116.82 J g^-1, respectively. In addition, the addition of HCFoam-Fe has a certain improvement on the thermal conductivity of the phase change material.

In order to further improve the thermal conductivity of the composites, porous carbon 4C was prepared by carbonization at high temperature using HCFoam-Fe4 as template. The effect of carbonization temperature on the porous structure was studied. The results showed that with the increase of temperature, the specific surface area of 4C increased, the total pore volume increased, and the pore size distribution was wider. The optimum carbonization temperature was 800 ^oC, and the surface area and total pore volume of the sample were 2532 m² g^-1 and 1.86 cm³ g^-1. DSC test results show that the load rates of PA, SA and PW on 4C-800 were 79.93 wt%, 81.90 wt% and 79.45 wt% respectively. In addition, the thermal conductivity of PA/4C tends to increase first and then decrease. The thermal conductivity of PA/4C-800 with the highest load ratio was 0.502 W m^-1 k^-1, which was 70.75% and 57.86% higher than pure PA and PA/HCFoam-Fe4 respectively. 

论文题目：热塑性聚氨酯导电复合材料的制备及其性能研究

毕业学生：宗孟静子

指导教师：吴唯

中文摘要：

随着电子产品的小型化和精密电子元件的发展，对于材料防电磁辐射、抗无线电波干扰以及静电防护等功能的需求日益迫切。高分子材料具有密度小、易加工、耐腐蚀及优异的物理机械性能，被广泛应用于电子电气领域。由于大部分高分子材料属于绝缘材料，电磁波很容易透过，因此对高分子材料进行改性，赋予其一定的导电性，从而具有电磁屏蔽防护能力，成为研发的热点之一。

本论文选用炭黑、碳纤维和膨胀石墨作为导电填料，以热塑性聚氨酯弹性体TPU作为树脂基体，制备导电TPU材料，系统研究了不同类型填料对材料导电性能的影响，建立了导电模型，为TPU的导电改性及其在高科技产业的应用提供了理论基础。

分别选用零维纳米级导电炭黑（Carbon Black, CB）、一维微米级导电碳纤维（Carbon Fiber, CF）、二维微米级导电膨胀石墨（Expanded Graphite, EG）以及CB/CF和CB/EG为复配导电填料，以热塑性聚氨酯为高分子基体，经过熔融共混，热压成型分别制备了CB/TPU、CF/TPU、EG/TPU、CB/CF/TPU和CB/EG/TPU复合材料。利用高阻计、四探针和宽频介电阻抗谱仪探究了材料的电性能；通过拉伸试验、扫描电子显微镜（SEM）和热重分析仪（TG）分别测定了材料的力学性能、微观结构和热稳定性。结果表明：上述三种单一填料下，材料的电阻率随填料添加量的变化都符合导电通路理论。其中CB/TPU的逾渗区间为10 ~ 14 phr，EG/TPU为8 ~ 12 phr，CF/TPU为6 ~ 10 phr，呈现CB > EG >CF的规律。复配CB/CF填料对导电性提高不明显，但是复配CB/EG材料对材料的导电性有一定的提高作用。

CB/TPU、CF/TPU和EG/TPU的介电常数、介电损耗等性能在逾渗区间内随填料量的增加而显著增加。CB/CF/TPU的介电性能随CF含量的增加而逐步增长，反映了CB/CF共同作用以构筑导电通路。CB/EG/TPU的介电常数在CB含量为8 phr时，随着EG含量的增加介电常数发生了较大幅度的增长，而当CB含量为12或16 phr时，介电常数随EG含量逐步平缓增加，且随着电场频率增加发生突降。CB/EG/TPU的介电损耗在CB含量为16 phr时，由于电导损耗占据主导，极化损耗变得不明显而表现出电导损耗特征，并且由于材料内部导电通路非常完善，交流电导率随频率增加而出现平台，说明CB/EG复配对材料的电性能有一定的提高作用。

不同于CF或EG，CB的加入能够提高TPU的力学性能，其最大拉伸强度，断裂伸长率和拉伸模量分别达到53.8 MPa和1066.7%和75.0 MPa。相比于单一填料下的CF/TPU材料或EG/TPU材料，CB/CF或CB/EG复配使力学性能有所回升。微观形貌观察到导电通路随填料含量的增加而逐渐形成。另外，CB或CF填料对材料的热稳定性有提高作用。

作为对新型导电填料的探索性实验。采用六羰基钨[W(CO)₆]作为前驱体，使用金属有机化学气相沉积（Metal Organic Chemical Vopour Deposition, MOCVD）技术制备了镀钨玻璃纤维（M-GF@Tungsten）。SEM观察到镀层均匀致密，纳米颗粒平均直径在70 nm左右，EDS和XRD分析表明镀层是β-W，电阻率测试表明M-GF@Tungsten的最小电阻率为4.10×10^-3 Ωžcm。研究成果为抗静电或电磁屏蔽材料的研发或应用提供了一种潜在的解决方案。

  Abstract:

With the miniaturization of electronic products and the increasing demand for precision electronic components, it is increasingly important to protect produtcs from electromagnetic shielding interference, radio wave interference, and electrostatic interference. Polymer materials are widely used in the field of electrical and electronic applications because of their low density, facile processing, corrosion resistance and excellent physical and mechanical properties. Since electromagnetic waves can easily pass through plastic, to modify polymer and impart conductivity for a certain electromagnetic shielding capability becomes a research focus.

In this thesis, carbon black, carbon fiber and expanded graphite were used as conductive fillers, and thermoplastic polyurethane elastomer TPU was used as resin matrix to prepare conductive TPU materials. The effects of different types of fillers on the electrical conductivity of the materials were systematically studied. A conductive model was established for TPU to provide a theoretical basis for conductive modification and its application in high-tech industries.

Zero-dimensional nano-scale conductive carbon black (CB), one-dimensional micro-scale conductive fiber (Carbon Fiber, CF), two-dimensional micro-scale conductive expanded graphite (Expanded Graphite (EG), CB/CF and CB/EG were used as conductive filler, thermoplastic polyurethane was polymer matrix, torque rheometer was used as processing method, CB/TPU, CF/TPU, EG/TPU, CB/CF/TPU and CB/EG/ were prepared by thermoforming. Electrical properties of the materials were investigated by high resistance meter, four-probe and wide-band dielectric impedance spectrometer. The mechanical properties, microstructure and thermal stability of the materials were determined by tensile test, scanning electron microscope (SEM) and thermogravimetric analyzer (TG), respectively. The results show that the conductivity of the three single fillers filled materials accords with the theory of conductive pathways. The percolation interval of CB/TPU, EG/TPU and CF/TPU is 10 ~ 14 phr, 8 ~ 12 phr and 6 ~ 10 phr, respectively, indicating the rule of CB > EG > CF. The conductivity improvement of CB/CF/TPU is not obvious, but the conductivity of CB/EG/TPU has a certain improvement effect.

The dielectric properties such as dielectric constant and dielectric loss of CB/TPU, CF/TPU and EG/TPU are significantly increased in the percolation interval. The dielectric properties of CB/CF/TPU increase gradually with the increase of CF content, reflecting the interaction of CB/CF to construct conductive pathways. The dielectric constant of CB/EG/TPU increases greatly with the increase of EG content when CB content is 8 phr, and the dielectric constant increases smoothly with EG content when CB content is 12 or 16 phr. As the frequency of the electric field increases, a sudden drop occurs. For the dielectric loss of CB/EG/TPU (CB content = 16 phr), the conductance loss dominates, and the polarization loss becomes insignificant, presenting a conductance loss. Since the internal conductive path of the material is quite completed, the AC conductivity performs a plateau, indicating that the electrical properties of the CB/EG compound filler have a certain improvement effect.

Different from CF or EG, the addition of CB can improve the mechanical properties of TPU, and the maximum tensile strength, elongation at break and tensile modulus can reach 53.8 MPa, 1066.7% and 75.0 MPa, respectively. Compared to CF/TPU materials or EG/TPU materials under a single filler, CB/CF or CB/EG can improve the mechanical properties. The microscopic morphology show that the conductive path gradually formed with the increase of the filler content. In addition, CB or CF fillers have an effect on the thermal stability of the material.

As an exploratory experiment on a novel conductive filler, tungsten hexacarbonyl [W(CO)₆] was used as the precursor, and tungsten-coated glass fiber (M-GF@Tungsten) was prepared by metal – organic chemical vapor deposition (MOCVD) in the last part of the study. SEM show that the coating is uniform and dense, and the average diameter of the nanoparticles is about 70 nm. EDS and XRD analysis show that the coating is β-W, and the resistivity test indicates that the minimum resistivity of M-GF@Tungsten is 4.10×10^-3 Ωžcm. This provides a potentially solution for the application of antistatic or diamagnetic shielding materials.

论文题目：聚丙烯酸酯/受阻酚阻尼杂化材料分子间氢键对阻尼性能的影响及热力学相图分析

毕业学生：马仁博

指导教师：吴唯

中文摘要：

丙烯酸酯橡胶（ACM）具有耐寒、耐油等优点，受阻酚杂化有效提升了其阻尼性能，使其在吸能减震领域应用广泛。本研究从氢键的角度，分析了受阻酚结构对氢键强度和数量的影响，探究了氢键与杂化体系相容性及阻尼性能间的关系，为半定量表征氢键与阻尼性能间的关系提供理论支持。

以丙烯酸酯橡胶AR72LS为基体，探究了AO300、TBBP、Irganox1035、AO1010四种结构不同的受阻酚的添加对阻尼性能的影响。通过傅里叶变换红外光谱（FTIR）以及Gaussian分峰拟合探究受阻酚结构对氢键的影响，再通过动态热机械分析（DMA）测试损耗因子（tand），对受阻酚的结构、氢键以及阻尼性能综合分析。研究表明，羟基受阻程度和体积越大，与聚合物形成的分子间氢键越弱，氢键强度AO300 > TBBP > Irganox1035 > AO1010。相对较弱的氢键对tand 的提升更有帮助，但分子间氢键较弱的小分子往往体积较大，易出现相容性差的问题，AO1010与ACM相容性不好。

由于受阻酚在长时间使用中易自聚集析出导致阻尼衰减。为研究受阻酚结构、分子间氢键对小分子自聚集的影响，本研究使用变温红外分别测定了受阻酚在晶区和氢键化的吸收峰，从受阻酚自身间氢键和聚合物-受阻酚间氢键共存且竞争的角度解释受阻酚自聚集现象以及引起杂化体系性能老化的原因。

使用熔点降低法和溶度参数法测定了Flory-Huggins 相互作用参数χ，获得spinodal曲线，并绘制了热力学相图。研究表明，随着温度升高，χ减小，杂化体系呈现上临界共溶温度相行为（UCST）。提高小分子-聚合物间氢键强度可有效降低χ值，增大羟基受阻程度以及范德华体积会使χ变大，影响体系稳定性。相图对于优化杂化体系配方，预测杂化体系相行为具有良好的指导作用。

  Abstract:  

Acrylate rubber (ACM) has the advantages of cold resistance and oil resistance. The hybrid of hindered phenol effectively improves its damping performance and makes it widely used in the field of energy absorption and shock absorption. From the point of view of hydrogen bond, the influence of hindered phenol structure on the strength and quantity of hydrogen bond is analyzed, and the relationship between hydrogen bond and compatibility and damping property of hybrid system is explored, which provides theoretical support for semi-quantitative characterization of the relationship between hydrogen bond and damping property.

The effects of the addition of hindered phenols with four different structures, AO300, TBBP, Irganox1035 and AO1010, on the damping properties of acrylate rubber AR72LS were investigated. Fourier transform infrared spectroscopy (FTIR) and Gaussian peak fitting were used to investigate the effect of hindered phenol structure on hydrogen bond. Dynamic thermomechanical analysis (DMA) was used to test the loss factor (tand), and the structure, hydrogen bond and damping properties of hindered phenol were comprehensively analyzed. The results show that larger hindered degree and volume of hydroxyl group lead to weaker intermolecular hydrogen bond formed with the polymer, and the hydrogen bond strength AO300 > TBBP > Irganox1035 > AO1010. The relatively weak hydrogen bond is more helpful for the enhancement of tand, but the small molecules with weaker hydrogen bond between molecules tend to be larger in volume, and are prone to poor compatibility.

Damping attenuation is caused by the self-aggregation of hindered phenols during long-term use. In order to study the effect of hindered phenol structure and intermolecular hydrogen bond on small molecule self-aggregation, the absorption peaks of hindered phenol in crystalline region and hydrogen bonding were measured by temperature-dependent infrared spectroscopy. The phenomenon of hindered phenol self-aggregation and the aging of hybrid system were explained from the point of view of coexistence and competition of hindered phenol self-hydrogen bond and polymer-hindered phenol hydrogen bond.

The Flory-Huggins interaction parameters χ were measured by melting point reduction method and solubility parameter method. Spinodal curves were obtained and thermodynamic phase diagrams were drawn. The results show that with the increase of temperature, χ decreases, and the hybrid system exhibits the phase behavior of supercritical eutectic temperature (UCST). Increasing hydrogen bond strength between small molecule and polymer can effectively reduce χ value. Increasing hydroxyl hindrance and Van der Waals volume will increase χ and affect the stability of the system. Phase diagrams play a good role in optimizing the formulation of hybrid system and predicting the phase behavior of hybrid system.

论文题目：芳纶纤维表面重铸及其对AF/TPU复合材料增强机理研究

毕业学生：刘江

指导教师：吴唯

中文摘要：

本研究采用表面重铸法对芳纶纤维（AF）表面进行改性，设计出具有不同微观形貌和化学性质的AF，具体改性方法为两步：第一步先对AF表面进行水解，使AF表面产生活性基团-COOH和-NH₂，接着利用水热合成法在AF表面着种ZnO纳米颗粒；第二步利用水热合成法在ZnO-AF表面倒伏生长AACH纳米线。通过傅立叶红外光谱仪，扫描电子显微镜，能谱仪，热重分析仪和电子万能拉力机等仪器对改性前后AF进行了性能测试和表征。研究结果发现：AF的最佳水解时间为40min，ZnO纳米颗粒的最佳着种次数为3次，AACH纳米线的最佳生长时间为16h。

将最佳改性条件下的AF与TPU熔融共混成型，制备AF/TPU，ZnO/TPU，AACH-AF/TPU三种复合材料，测定了不同纤维含量下的拉伸性能。实验结果发现：7%ZnO-AF/TPU复合材料的拉伸强度从纯TPU的33.39 Mpa提高到了38.39 Mpa，断裂伸长率保持在1200%左右；AACH-AF/TPU复合材料的增强效果最明显，当添加量为7%时，其拉伸强度达到最大值44.83 Mpa，但断裂伸长率下降了18.64%。ZnO-AF和AACH-AF都一定程度降低了TPU树脂的热稳定性。并将材料断面SEM图像结合剥离数理论和粗糙表面与光滑表面的弹性接触模型，分析了ZnO-AF/TPU和AACH-AF/TPU复合材料的增强机理。

  Abstract:  

In this study, the surface of aramid fiber (AF) was modified by surface recasting method, and the AF with different micromorphology and chemical properties was designed. The specific modification method contained two steps: the first step was to hydrolyze the AF surface. The active surface groups -COOH and -NH₂ were generated on the AF surface, and then ZnO nanoparticles were seeded on the AF surface by hydrothermal synthesis; the second step was to grow AACH nanowires on the surface of ZnO-AF by hydrothermal synthesis. The performance of the AF before and after modification were tested and characterized by means of Fourier transform infrared spectrometer, scanning electron microscope, energy spectrometer, thermogravimetric analyzer and electronic universal tensile machine. The results showed that the optimal hydrolysis time of AF was 40 min, the optimal seeding number of ZnO nanoparticles was 3 times, and the optimal growth time of AACH nanowires was 16 h.

The AF and TPU, ZnO/TPU and AACH-AF/TPU composites were prepared by melt blending AF and TPU under the optimal modification conditions, and the tensile properties under different fiber contents were determined. The experimental results show that the tensile strength of 7% ZnO-AF/TPU composites increases from 33.39 Mpa of pure TPU to 38.39 Mpa, and the elongation at break remains around 1200%. The reinforcement effect of AACH-AF/TPU composites is most obvious. When the addition amount is 7%, the tensile strength reaches a maximum value of 44.83 MPa, but the elongation at break decreases by 18.64%. Both ZnO-AF and AACH-AF reduce the thermal stability of TPU resin to a certain extent. The reinforcement mechanism of ZnO-AF/TPU and AACH-AF/TPU composites was analyzed by combining the SEM image of the material section with the peeling number theory and the elastic contact model between the rough surface and the smooth surface.