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A stable aqueous nanocomposite dispersion containing cellulose whiskers and a polymer matrix was prepared via miniemulsion polymerization. We were able to prepare a stable dispersion with a 250 wt % solid content and a cellulose whiskers content ranging from 1 up to 5 wt % based on polymer content. Cellulose nanocrytals suspension was mixed with monomers phase in presence of anionic or cationic surfactant and a stabilizing additive acting as a hydrophobe. After sonication for a short time to obtain a stable emulsion of small droplet polymerisation reaction was trigged by the addition of the initiator. The nanocomposite dispersion was characterized using dynamic light scattering, ζ-potential measurement, transmission electron microscopy (TEM), atomic force microscopy (AFM) and FE-SEM. It was found that the particle size of the prepared suspensions is in the range of 90-600 nm, and the final nanocrystals composite is stable for months.Films obtained by casting followed by water evaporation and particle coalescence were analyzed by differential scanning calorimetry, dynamic mechanical analysis, and tensile testing. The nanocomposite maintained high transparency, and their storage elastic modulus increased tediously with the increasing nanowhiskers content. / Des dispersions de nanocomposites stables à matrice polymérique et à base de whiskers de cellulose ont été préparées par polymérisation en miniémulsion, dont on peut atteindre 5 % en masse. Ce procédé permet d’obtenir une distribution homogène des nanofibres autour des particules de polymère, et empêche ainsi les risques d’agglomération.La caractérisation de ces dispersions a été réalisée en recourant à divers techniques comme la diffusion dynamique de la lumière, zetamètrie, le microscope électronique à transmission (MET), à force atomique (AFM) et à effet de champs. Nous avons montré que l’accroissement du taux de nanoparticules s’accompagne par une augmentation de la taille des particules de polymères.Les propriétés des films de nanocomposites, obtenus après évaporation de l’eau et coalescence des particules ont été analysées par calorimétrie différentiel à balayage (DSC), analyse mécanique dynamique (DMA) et par essai de traction.

Call number: LD2668 .T4 1964 B15 / Master of Science

Thesis (Ph. D.)--Auburn University, 2008. / Abstract. Vita. Includes bibliographical references (p. 107-109).

Thesis (M.S. in neuroscience)--Washington State University, August 2008. / Includes bibliographical references (p. 22-29).

Thesis (Ph. D. in Psychology)--Vanderbilt University, May 2006. / Title from title screen. Includes bibliographical references.

For years, the alloy of choice for electroplating electronic components has been tin-lead (Sn-Pb) alloy. However, the legislation established in Europe on July 1, 2006, required significant lead (Pb) content reductions from electronic hardware due to its toxic nature. A popular alternative for coating electronic components is pure tin (Sn). However, pure tin has the tendency to spontaneously grow electrically conductive Sn whisker during storage. Sn whisker is usually a pure single crystal tin with filament or hair-like structures grown directly from the electroplated surfaces. Sn whisker is highly conductive, and can cause short circuits in electronic components, which is a very significant reliability problem. The damages caused by Sn whisker growth are reported in very critical applications such as aircraft, spacecraft, satellites, and military weapons systems. They are also naturally very strong and are believed to grow from compressive stresses developed in the Sn coating during deposition or over time. The new directive, even though environmentally friendly, has placed all lead-free electronic devices at risk because of whisker growth in pure tin. Additionally, interest has occurred about studying the nature of other metal whiskers such as zinc (Zn) whiskers and comparing their behavior to that of Sn whiskers. Zn whiskers can be found in flooring of data centers which can get inside electronic systems during equipment reorganization and movement and can also cause systems failure.Even though the topic of metal whiskers as reliability failure has been around for several decades to date, there is no successful method that can eliminate their growth. This thesis will give further insights towards the nature and behavior of Sn and Zn whiskers growth, and recommend a novel manufacturing technique that has potential to mitigate metal whiskers growth and extend life of many electronic devices.

Call number: LD2668 .T4 1959 J64

by Chan To = 電鍍錫在銅質底材上晶鬚生長的硏究 / 陳濤. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / by Chan To = Dian du xi zai tong zhi di cai shang jing xu sheng chang de yan jiu / Chen Tao. / Abstract --- p.i / 論文摘要 --- p.ii / Acknowledgements --- p.iii / Table of Content --- p.v / Chapter Chapter 1 --- INTRODUCTION / Chapter 1.1 --- Lead-free movement and the problem of whisker --- p.1-1 / Chapter 1.2 --- Properties of tin and tin-copper intermetallics --- p.1-2 / Chapter ´Ø --- Tin --- p.1-2 / Chapter ´Ø --- Tin-copper intermetallics --- p.1-2 / Chapter 1.3 --- Literature Review of Whisker --- p.1-4 / Chapter 1.3.1 --- Feature of the whisker --- p.1-4 / Chapter 1.3.2 --- Conditions prone to whisker growth --- p.1-8 / Chapter 1.3.3 --- Growth mechanism of the whisker --- p.1-10 / Chapter 1.3.4 --- Methods to prevent or remove whisker --- p.1-11 / Chapter 1.4 --- Motivation & Aims of Studies --- p.1-12 / Chapter Chapter 2 --- EXPERIMENTAL & INSTRUMENTATION / Chapter 2.1 --- Sample Preparation --- p.2-1 / Chapter ´Ø --- Electroplating process --- p.2-1 / Chapter 2.2 --- Instrumentation --- p.2-6 / Chapter 2.2.1 --- Scanning Auger Microscope (SAM) analysis --- p.2-6 / Chapter ´Ø --- Experimental conditions --- p.2-9 / Chapter ´Ø --- Sample preparation for Auger analysis --- p.2-10 / Chapter ´Ø --- Depth profile analysis --- p.2-11 / Chapter ´Ø --- Mapping --- p.2-11 / Chapter ´Ø --- Line scan --- p.2-12 / Chapter 2.2.2 --- X-ray diffractometer (XRD) --- p.2-12 / Chapter 2.2.3 --- Scanning Electron Microscope (SEM) --- p.2-13 / Chapter Chapter 3 --- INFLUENCE OF CATHODIC/ANODIC ELECTROCHEMICAL CLEANING ON THE WHISKER GROWTH / Chapter 3.1 --- Introduction --- p.3-1 / Chapter 3.2 --- Theory --- p.3-2 / Chapter ´Ø --- Reactions occurring at the anode/cathode --- p.3-3 / Chapter 3.3 --- Sample description --- p.3-5 / Chapter 3.4 --- Results and discussion --- p.3-5 / Chapter ´Ø --- Surface morphology before electroplating --- p.3-5 / Chapter ´Ø --- Whisker observation --- p.3-7 / Chapter 3.5 --- Summary --- p.3-18 / Chapter Chapter 4 --- INFLUENCE OF COPPER CONCENTRATION IN THE PLATING BATH ON COPPER DIFFUSION AND WHISKER FORMATION / Chapter 4.1 --- Introduction --- p.4-1 / Chapter 4.2 --- Theory and Literature Review --- p.4-2 / Chapter ´Ø --- Diffusion kinetic --- p.4-2 / Chapter ´Ø --- Influence of solute atoms --- p.4-5 / Chapter 4.3 --- Sample description --- p.4-6 / Chapter 4.4 --- Results and discussion --- p.4-6 / Chapter ´Ø --- SEM observations --- p.4-6 / Chapter ´Ø --- Cross-sectional analysis --- p.4-8 / Chapter ´Ø --- Surface and depth profile analysis --- p.4-15 / Chapter ´Ø --- XRD analysis --- p.4-21 / Chapter 4.5 --- Summary --- p.4_24 / Chapter Chapter 5 --- ANNEALING EFFECT ON THE WHISKER GROWTH / Chapter 5.1 --- Introduction --- p.5-1 / Chapter 5.2 --- Theory and Literature Review --- p.5-2 / Chapter 5.3 --- Sample description --- p.5-3 / Chapter 5.4 --- Results and discussion --- p.5-4 / Chapter ´Ø --- SEM whisker observation --- p.5-4 / Chapter ´Ø --- Cross-sectional Auger analysis --- p.5-4 / Chapter ´Ø --- Surface and depth profile analysis --- p.5-16 / Chapter 5.5 --- Summary --- p.5-27 / Chapter Chapter 6 --- FORMATION MECHANISM OF THE STRIATION ON WHISKER / Chapter 6.1 --- Introduction --- p.6-1 / Chapter 6.2 --- Results and discussion --- p.6-2 / Chapter ´Ø --- Texture of the striation --- p.6-2 / Chapter ´Ø --- Time evolution in the surface morphology --- p.6-6 / Chapter ´Ø --- Stage of whisker growth --- p.6-6 / Chapter 6.3 --- Summary --- p.6-12 / Chapter Chapter 7 --- CONCLUSIONS & FUTURE STUDIES / Chapter 7.1 --- Conclusions --- p.7-1 / Chapter 7.2 --- Future studies --- p.7-3 / Reference