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Made available in DSpace on 2014-12-17T14:07:16Z (GMT). No. of bitstreams: 1 AntonioCAM_DISSERT.pdf: 2526278 bytes, checksum: 858d8dc4858eb48a9d6ce6faab8763d4 (MD5) Previous issue date: 2014-02-26 / Universidade Federal do Rio Grande do Norte / Epoxy based nanocomposites with 1 wt % and 3 wt % of nanographite were processed by high shear mixing. The nanographite was obtained by chemical (acid intercalation), thermal (microwave expansion) and mechanical (ultrasonic exfoliation) treatments. The mechanical, electrical and thermal behavior of the nanocomposites was determined and evaluated as a function of the percentage of reinforcement. According to the experimental results, the electrical conductivity of epoxy was not altered by the addition of nanographite in the contents evaluated. However, based on the mechanical tests, nanocomposites with addition of 1 wt.% and 3 wt.% of nanographite showed increase in tensile strength of 16,62 % and 3,20 %, respectively, compared to the neat polymer. The smaller increase in mechanical strength of the nanocomposite with 3 wt.% of nanographite was related to the formation of agglomerates. The addition of 1 wt.% and 3 wt.% of nanographite also resulted in a decrease of 6,25 % and 17,60 %, respectively, in the relative density of the material. Thus, the specific strength of the nanocomposites was approximately 33,33 % greater when compared to the neat polymer. The addition of 1 wt.% and 3 wt.% of nanographite in the material increased the mean values of thermal conductivity in 28,33 % and 132,62 %, respectively, combined with a reduction of 26,11 % and 49,80 % in volumetric thermal capacity, respectively. In summary, it has been determined that an addition of nanographite of the order of 1 wt.% and 3 wt.% produced notable elevations in specific strength and thermal conductivity of epoxy / Nanocomp?sitos a base de resina ep?xi e nanografite foram processados por mistura de alto cisalhamento, com concentra??es de 1 % e 3 % p/p de refor?o. O nanografite foi obtido atrav?s de tratamentos: qu?mico (intercala??o ?cida), t?rmico (expans?o por microondas) e mec?nico (esfolia??o por ultrassom). Os comportamentos mec?nico, el?trico e t?rmico dos materiais obtidos foram analisados em fun??o da porcentagem de refor?o. De acordo com os resultados obtidos, n?o foram verificadas altera??es na condutividade el?trica do ep?xi com a adi??o de nanografite, nos percentuais estudados. Entretanto, com base nos ensaios mec?nicos observou-se que os nanocomp?sitos com adi??o de 1 % p/p e 3 % p/p de grafite expandido apresentaram aumento na resist?ncia ? tra??o de 16,62 % e 3,20 % respectivamente, em rela??o ao pol?mero puro. O menor aumento de resist?ncia mec?nica para os nanocomp?sitos com 3 % p/p de nanografite foi relacionado com a forma??o de aglomerados. A adi??o de 1 % p/p e 3% p/p de nanografite tamb?m resultou em uma diminui??o de 6,25 % e 17,60 %, respectivamente, na densidade relativa do pol?mero. Portanto, a eleva??o da resist?ncia espec?fica dos nanocomp?sitos foi de aproximadamente 33,33% para os dois nanocomp?sitos, em rela??o ao pol?mero puro. A adi??o de 1 % p/p e 3 % p/p de nanografite no material aumentou os valores m?dios de condutividade t?rmica em 28,33 % e 132,62 %, respectivamente, combinado com uma redu??o de 26,11 % e 49,80 %, respectivamente, na capacidade t?rmica volum?trica. Em resumo, verificou-se que uma adi??o de nanografite da ordem de 1 % e 3 % p/p produziram eleva??es not?veis na resist?ncia mec?nica espec?fica e condutividade t?rmica do ep?xi

This thesis deals with processing of nanocellulose originating from pulps, with focus on mechanical pulp fibres and fines fractions. The nanocellulose materials produced within this research project were tested for different purposes ranging from strength additives in paper and paperboard products, via composite films to foam materials. TAPPI (Technical Association of Pulp &amp; Paper Industry) has recently suggested a standard terminology and nomenclature for nanocellulose materials (see paper I). In spite of that we have decided to use the terms nano-ligno-cellulose (NLC), microfibrillated cellulose (MFC), nanofibrillated cellulose (NFC) and nanocellulose (NC) in this thesis . It is well-known that mainly chemical pulps are used as starting material in nanocellulose production. However, chemical pulps as bleached sulphite and bleached kraft are quite expensive. One more cost-effective alternative can be to use fibres or fines fractions from thermo-mechanical pulp (TMP) and chemi-thermomechanical pulp (CTMP).   In paper II-IV, fractionation has been used to obtain fines fractions that can easily be mechanically treated using homogenisation. The idea with this study was to investigate the possibility to use fractions of low quality materials from fines fractions for the production of nanocellulose. The integration of a nanocellulose unit process in a high-yield pulping production line has a potential to become a future way to improve the quality level of traditional products such as paper and paperboard grades.   Paper III describes how to utilise the crill measurement technique as a tool for qualitative estimation of the amount of micro- and nano-material produced in a certain process. The crill values of TMP- and CTMP-based nanocelluloses were measured as a function of the homogenisation time. Results showed that the crill values of both TMP-NLC and CTMP-NLC correlated with the homogenisation time. In Paper V pretreating methods, hydrogen peroxide and TEMPO are evaluated. Crill measurement showed that hydrogen peroxide pretreatment (1% and 4%) and mechanical treatment time did not improve fibrillation efficiency as much as expected. However, for TEMPO-oxidised nanocelluloses, the crill value significantly increased with both the TEMPO chemical treatment and mechanical treatment time. In paper V-VII TEMPO-mediated oxidation systems (TEMPO/NaBr/NaClO) are applied to these fibres (CTMP and Sulphite pulp) in order to swell them so that it becomes easy to disrupt the fibres into nanofibres with mechanical treatment.   The demand for paperboard and other packaging materials are steadily increasing. Paper strength properties are crucial when the paperboard is to withstand high load. A solution that are investigated in papers IV and VI, is to use MFC as an alternative paper strength additive in papermaking. However, if one wish to target extremely higher strength improvement results, particularly for packaging paperboards, then it would be fair to use MFC or cationic starch (CS). In paper VI CS or TEMPO-based MFC was used to improve the strength properties of CTMP-based paperboard products. Results here indicate significant strength improvement with the use of different levels of CS (i.e., 20 and 10 kg t–1) and 5% MFC. The strengthening impact of 5% MFC was approximately equal to that of 10 kg t–1 of CS.   In paper VII, NFC and nanographite (NG) was used when producing composite films with enhanced sheet-resistance and mechanical properties. The films produced being quite stable, flexible, and bendable. Realising this concept of NFC-NG composite film would create new possibilities for technological advancement in the area of high-yield pulp technology.  Finally, in paper VIII, a new processing method for nanocellulose is introduced  where an organic acid (i.e., formic acid) is used. This eco-friendly approach has shown to be successful, a nanocellulose with a uniform size distribution has been produced. / <p>Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 5 och 7 inskickade, delarbete 6 och 8 manuskript.</p><p>At the time of the doctoral defence the following papers were unpublished: paper 5 and 7 submitted, paper 6 and 8 manuscripts.</p>

Due to the rapid development of technology, electrical products are being shipped all over the world. The electronic components have gotten greater in capacity but are smaller in size, making them sensitive to electrostatic discharge (ESD). ESD packaging protects sensitive components from electrostatic discharge and electrical fields. There are different types of packaging solutions depending on the sensitivity of the product. Rigid packaging of insulating paperboard, impregnated with a thin, conductive carbon layer was used in this study. The conductive material is supposed to lead the static electricity away from the product, to the packaging which is insulated, where it safely can discharge. The inside of the packaging, normally dressed in a foam to protect the device inside, is supposed to be replaced with paperboard. The purpose of this master thesis is to investigate whether or not an ESD-packaging can be created by coating a paperboard with a dispersion containing nanographite and nanocellulose. Solid Bleached Board is a paperboard made by the mill Iggesund Paperboard, used for graphical products and packaging of high quality. Paperboard is made from cellulose, an environmentally sustainable raw material from the forest. Classifications of materials used in ESD packaging-solutions are divided into how quickly electricity moves through the material. Carbon is normally within the range of 10^2 to 10^6 Ω for sheet- and volume resistance. Maximal charge and maximal electrical discharge of the packaging are by standard not supposed to exceed 100 V and 50 nJ. Two different nanographite dispersions with different binders (polyvinyl alcohol and cellulose nanofibres) have been made. These have been coated onto the paperboard using a bench-coater. Measurements of ESD- and paperboard-properties have been performed onto the paperboard. The measured values were within the range of what was considered acceptable to be able to create an ESD packaging. The prototype was designed materially with solid bleached board, coated with a dispersion made of 220g nanographite, 22g cellulose nanofibres and 3791g water with a solid content of 8,2%. The design has been developed with the company's existing packaging in mind together with information about the already existing ESD packages. The results from the measurements show that it is fully possible to create and produce ESD-packaging, but needs further testing after this thesis. Societal, ethical and environmental aspects have been considered during the entire study. / På grund av den snabba tekniska utvecklingen transporteras elektriska produkter över hela världen. Elektroniska komponenter har fått större kapacitet men är mindre i storleken vilket gör dem känsliga för elektrostatisk urladdning (ESD). ESD-förpackningar skyddar känsliga komponenter från elektrostatisk urladdning och elektriska fält. Det finns olika typer av förpackningslösningar beroende på produktens känslighet. Styva förpackningar av isolerande kartong, impregnerade med ett tunt, elektriskt ledande kolskikt användes i denna studie. Det ledande materialet leder den statiska elektriciteten bort från produkten, till förpackningen som är isolerad, där den säkert kan urladdas. Förpackningens insida, som normalt är klädd med ett skum för att skydda produkten inuti, är tänkt att ersättas med kartong. Syftet med examensarbetet är att undersöka om en ESD-förpackning kan skapas genom att bestryka ett kartongark med en dispersion innehållande nanografit och nanocellulosa. Homogen helblekt kartong (Solid Bleached Board, SBB) är en kartong tillverkad av pappersbruket Iggesund Paperboard, som används för grafiska produkter och förpackningar av hög kvalitet. Kartong är tillverkad av cellulosa, ett miljövänligt och hållbart material från skogen. Klassificeringar av material som används i ESD-förpackningar är indelade i hur snabbt elektricitet rör sig genom materialet. Kol ligger normalt inom intervallet 10^2 till 10^6 Ω för yt- och volymresistans. Maximal uppladdning och maximal elektrisk urladdning av förpackningen ska inte överstiga 100 V och 50 nJ. Två olika dispersioner med olika bindemedel (polyvinylalkohol och cellulosa nanofibrer) har tillverkats. Dessa har bestrukits på kartongen med en bänkbestrykare. Mätningar av ESD- och kartong-egenskaper har utförts på kartongen. Mätdata låg inom det intervall som ansågs vara acceptabelt för att kunna skapa en ESD-kartong. Prototypen, sample B, är designad materiellt med homogen helblekt kartong, bestruken med en dispersion gjord av 220g nanografit, 22g cellulosa nanofibrer och 3791g vatten med en torrhalt på 8,2%. Designen har utvecklats med företagets befintliga förpackningar i åtanke tillsammans med information om de redan existerande ESD-förpackningarna. Resultaten från mätningarna visar att det är fullt möjligt att skapa och producera ESD-kartong, men det kräver ytterligare tester efter denna studie. Samhälleliga-, etiska- och miljöaspekter kommer att beaktas under hela studien.