吸附制冷用混合吸附剂导热性能的研究

用水溶液挤压法制备了24个CaCl2/ENG成型混合吸附剂样品,利用目前闪光扩散法测量导热系数最先进的仪器——LFA447激光导热仪对样品进行了导热系数的测试。研究表明:挤压法制备的样品垂直于压力方向上的导热系数高于平行于压力方向上的,大约是其1.1~1.2倍,具有各向异性;在一定范围内,随着固化密度的增加导热系数不断增加,随着氯化钙和膨胀石墨质量比的减小导热系数也不断增大;在氯化钙和ENG的质量比为2∶1,固化密度从600kg/m3增加到700kg/m3的过程中导热系数增加得最为明显,固化密度和膨胀石墨的含量对成型吸附剂样品的导热系数的影响有耦合作用。     

吸附剂之间及其与铜表面之间的传热强化研究

测试了颗粒吸附剂（沸石／聚苯胺复合物）、成型吸附剂与铜表面之间的接触热阻以及导热胶对吸附剂与铜表面之间的接触热阻的影响。结果表明,成型吸附剂能有效地强化吸附剂与铜表面之间的传热, 导热胶能进一步强化吸附剂与铜表面之间的传热。     

一种能同时提高固体吸附制冷吸附剂

通过在沸石分子筛中添加膨胀石墨和发泡剂并固结成型进行处理,使吸附剂的导热系数和渗透性有了显著提高,并测定了几种吸附剂的导热系数,采用SEM观察了发泡前后的沸石分子筛的晶体结构和微观形貌的变化,分析了膨胀石墨所具有的特性是使其成为合适的添加剂的原因.通过TGA测试表明吸附剂的传质性能有提高.     

一种能同时提高固体吸附制冷吸附剂传热传质性能的方法

通过在沸石分子筛中添加膨胀石墨和发泡剂并固结成型进行处理,使吸附剂的导热系数和渗透性有了显著提高,并测定了几种吸附剂的导热系数,采用SEM观察了发泡前后的沸石分子筛的晶体结构和微观形貌的变化,分析了膨胀石墨所具有的特性是使其成为合适的添加剂的原因。通过TGA测试表明吸附剂的传质性能有提高。     

吸附式制冷中吸附剂传热传质的强化

对吸附式制冷系统中吸附剂的两种关键性能－有效吸附量及导热系数进行了实验及理论研究。测量了几种吸附剂的上述性能并进行了数据拟合,分析了吸附剂吸附性能及导热系数对吸附制冷系统效率的影响,提出了以吸附制冷最佳经济效率为目标函数的吸附剂性能强化手段,并进行了一些实验研究,取得了较好的效果。     

盐湖铝系提锂吸附剂成型条件的影响研究

铝系锂吸附剂成型颗粒在盐湖卤水提锂工业应用过程中存在吸附容量低、吸附速率慢和吸附剂粉末脱落等问题。基于现有反溶剂法挤压成型工艺,对盐湖铝系提锂吸附剂成型条件的影响进行了系统性研究。实验结果显示吸附剂成型颗粒粒径越小,达到吸附平衡越快,当颗粒直径d<1 mm时,吸附剂颗粒可在24 h左右达到吸附平衡;降低黏结剂浓度可有效加快吸附剂颗粒的吸附速率,但黏结剂浓度过低会导致其对粉末的包裹性下降;吸附剂颗粒的吸附速率与致孔剂添加比例成正比,当致孔剂添加比例为20%时,吸附剂颗粒能在4 h内完成快速吸附阶段,吸附平衡时对察尔汗高镁锂比盐湖卤水中锂的吸附容量可达4.97 mg·g^-1。     

瓷质砖坯体的导热系数及其影响因素

探讨了温度、成型压力、含湿率、添加剂对坯体导热系数的影响。试验结果表明：对于相同化学组成的瓷质砖坯体,在保证同一实验平均温度的情况下,其导热系数随着成型压力和含湿量的增加而非线地增大;在低温段,其导热系数随着温度的升高而减小;添加物对坯体导热系数影响比较复杂。     

硬脂酸修饰MoS_2纳米颗粒的制备及其强化传热性能

以硬脂酸为表面修饰剂,采用表面修饰法制备了硬脂酸修饰MoS_2(SA-MoS_2)纳米颗粒,并合成了导热油基MoS_2纳米流体,对产物进行了表征和测定了纳米流体的高温导热系数。结果表明,硬脂酸通过化学反应修饰在MoS_2纳米颗粒表面,SA-MoS_2纳米颗粒具有很好的亲油性,在导热油中具有良好的分散稳定性;SA-MoS_2纳米颗粒属于无定型非晶态,为不完全规则的球形纳米颗粒,尺寸约为30~90 nm;在40~120℃,纳米流体的导热系数随着温度的增大而略有减小,而温度大于120℃,导热系数与温度的变化呈正比;SA-MoS_2纳米颗粒对导热油的导热系数具有显著的强化作用,导热系数提高率与纳米颗粒的质量浓度呈正比,仅添加0.60 wt%的SA-MoS_2纳米颗粒时,纳米流体的导热系数比基础油提高了34.3%~51.2%。这种强化传热特点在高温传热工质和热能工程中具有重要的应用价值。     

吸附器中导热胶热传导系数的研究

本文在研究吸附式热泵吸附器传热性能的特性基础上，发现导热胶能有效降低吸附剂与吸附换热器表面间的接触热阻，阻后研制并测试了导热胶对颗粒吸附剂与吸附换热器表面之间以及成型吸附剂与吸附换热器表面之间接触热阻的影响。实验结果表明，导热胶是降低吸附剂与金属表面之间接触热阻的一种有效方法，可以提高吸附剂与金属表面之间的传热性能，而对吸附剂的吸附性能影响不大，为强化两种不同介质之间的传热提供了新的技术途径。     

改性沸石对气态汞吸附的实验研究

为了获得消耗量小、性能高效的燃煤烟气脱汞吸附剂,采用活性MnO2浸渍、FeCl3浸渍和不同温度下渗硫等方法,对沸石进行了改性,制得一系列改性沸石吸附剂。采用固定床吸附的方式,对吸附剂在不同条件下的吸附效果进行了测试,筛选出一种高效、廉价的MnO2浸渍沸石吸附剂,和原沸石吸附剂相比,改性沸石吸附剂对汞蒸气的吸附能力有较大提高,有效吸附时间大大增加,在有效吸附时间内,穿透率大大降低。改性后的沸石吸附能力大大提高的原因在于其吸附过程中,除了物理吸附,还发生了化学吸附。     

导电聚苯胺复合纤维的研制

利用氧化聚合法，在室温、常压下快速将苯胺聚合在极性纤维表面，从而赋予纤维优良的导电性能，其表面电阻达到１０￣３Ω／ｃｍ。同时对导电性能的耐洗牢度进行了初步研究。     

In situ polymerization of aniline on acrylamide grafted cotton

In this article, polyaniline (PANI)/cotton composite were prepared by in situ polymerization on the grafted cotton. First, acrylamide was grafted onto cotton cellulose using a radical graft polymerization process and some influencing factors were studied. Then polyaniline/cotton conductive composite fabrics were prepared by chemical in situ polymerization on the grafted cotton. The influences of the concentration of ammonium persulfate, aniline, hydrochloric acid, and the reaction time to the conductivity and K/S of composite fabric were studied. By contrasting, graft brought on an improvement of about one order of magnitude to the conductivity of composite fabric. The strength, TG, FTIR‐ATR, and SEM of prepared fabric were measured. The thermal stability and tear strength of composite fabric reduced, whereas PANI exhibited a rough but uniform, coherent PANI coating on surface of cotton fiber. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

导电聚吡咯／聚酯复合织物研究

采用吡咯气固相沉积聚合法制备导电聚吡咯／聚酯复合织物，研究了处理工艺对聚酯织物结构与性能的影响。结果表明，聚酯织物先经碱减量处理60 min，再经1.0 mol／L氧化剂处理30 min，吡咯单体气固相沉积聚合8次可制得具有较好导电性能的聚吡咯聚酯复合织物，其表面电阻约为330 Ω／cm，其力学性能的降低程度不大，聚吡咯均匀致密地沉积在聚酯织物表面。     

Conductive fibers based on poly(ethylene terephthalate)–polyaniline composites manufactured by electrochemical polymerization

A novel method of manufacturing composite conductive fibers was developed through electrochemical polymerization with an apparatus consisting of insulating fibers, cotton fabrics as electrolytic solution holders, an electrolytic solution, and planer electrodes. By this method, poly(ethylene terephthalate) (PET) fibers coated with polyaniline (PAN) were prepared readily and yielded PET–PAN composite conductive fibers (PPCFs). The content of PAN in PPCFs increased with an increase in both the aniline concentration in the electrolytic solution and the polymerization voltage, although it did not depend on the load applied to the electrodes. Observations of the PPCF surface by scanning electron microscopy confirmed that the formation processes of PPCFs could be divided into three steps: (1) fine (nanometer‐size) granular PAN was generated from the anode and adsorbed onto the PET fiber surface, (2) the size of the granular PAN increased up to about 90 nm in a short time, and (3) the granular PAN was linked together to form networks. The conductivity of PPCFs increased with an increasing content of PAN networks. The surface resistance of the PPCF fabric was about 3 × 10⁵ Ω/□ at a PAN content of approximately 2 wt %. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1073–1078, 2003     

“SmFeO<Subscript>3</Subscript>-Polyanaline Composite: Synthesis and Its Various Characterizations”

Polyaniline-SmFeO₃ composite are prepared by chemical oxidative polymerization method. Structural, vibrational, morphological, thermal, optical, magnetic and dielectric properties of the samples are explored by X-ray diffraction, Fourier Transform Infrared (FTIR), Scanning Electron Microscope (SEM), Thermo Gravimetric Analysis, UV–Vis, Vibrating Sample Magnetometer, and dielectric measurements. Crystalline nature of the composite has been obtained due to the presence of SmFeO₃ particles in polyaniline and retains orthorhombic structure with Pbnm space group. A noticeable impact on various parameters (grain size, stress and dislocation density) can be observed. FTIR analysis confirms the formation of polyaniline. The obtained vibrational bands of polyaniline structure changes due to the presence of SmFeO₃ particles. Surface/particle morphology of the composite has been observed from SEM micrographs. The thermal stability of polyaniline is considerably enhanced in composite format. From the evaluation of optical absorption data, a reduction in optical band gap (E_g) is observed. The real and imaginary part of dielectric constant was found to follow the universal dielectric response. From the ac conductivity investigations, charge carriers follow the correlated barrier hopping transport mechanism.     

Synthesis of high conductivity Polyaniline/Ag/graphite nanosheet composites via ultrasonic technique

A new process for the synthesis of high conductivity polyaniline/Ag/graphite nanosheet (PANI/Ag/NanoG) composites was developed. Graphite nanosheet was prepared by treating the expanded graphite in aqueous alcohol solution using sonication, and a uniform silver film about 470 nm thick was obtained on graphite nanosheet surface via an improved electroless plating method. Then PANI/Ag/NanoG composites were fabricated via in situ polymerization of aniline monomer in the presence of silver coated graphite nanosheet through using ultrasonic technique. The sliver particles and composites were evidenced by scanning and transmission electron microscopy examinations, the results showed that the silver coated graphite nanosheet particles played an important role in forming conducting bridge in polyaniline matrix. According to the electrically test, the conductivity of the PANI/Ag/NanoG composites was dramatically increased compared with pure PANI. From the thermogravimetric analysis, the PANI/Ag/NanoG composites exhibited a beneficial effect on the thermal stability of pure PANI.     

聚合物/新型导热填料复合电介质的研究进展

综述了非常规新型导热粒子如纳米金刚石、碳化物、铁电陶瓷及其他无机功能粒子及其填充聚合物电介质的最新研究进展，重点探讨了新型导热粒子的含量、表面改性、加工方式等对聚合物复合材料的导热及介电性能的影响。介绍和分析了基于有机分子晶体为连续声子传递通路改性聚合物导热性能的研究及机理;在基体树脂内利用无机导热粒子及有机分子晶体可构筑连续的声子导热通路，从而达到降低界面热阻、提高体系热导率的目的。相比传统导热粒子，新型导热粒子在提高绝缘聚合物热导率的同时，还赋予体系其他物理性能如磁性、优良介电性能及储能等性能。     

绝缘导热Si_3N_4/LLDPE复合材料的研制

用粉末法制备了Si3N4增强线型低密度聚乙烯(LLDPE)导热材料,研究了填料Si3N4对LLDPE熔融温度、结晶度、热导率、电绝缘性能及力学性能的影响.结果表明,加入Si3N4粒子,提高了LLDPE的熔融温度和结晶度;当w(Si3N4)为30%时,体系热导率达基体的6～7倍,热导率随Si3N4粒径的减小而增大,此时体系仍然具有较高电阻率及良好的介电性能,但力学性能明显下降.     

聚合物基热界面材料与导热性能研究进展

随着电子产品的小型化、集成化和功能化发展,功率密度及热流密度急剧上升,器件内巨大的散热和温压压力使电子设备的寿命和可靠性受到影响,因此对器件在运行过程中如何有效散热提出了更为苛刻的要求。开发及使用高性能导热基复合材料（热界面材料,TIM）降低接触热阻是解决电子设备散热问题的有效途径之一,热界面材料创新与优化备受关注。本文从基本的导热机理出发,阐述聚合物基热界面材料结构及导热强化方面最新进展,讨论导热填料和聚合物基体对复合材料性能的影响。重点对微纳结构的导热强化（协同）作用、构筑3D高导热微结构、导热填料和基质间的界面微结构和导热互穿网络结构等进行讨论,为设计高性能导热结构、制备开发新型高性能TIM提供参考。