Poly(1-methylpyrrol-2-ylsquaraine) (PMPS) particles are a fine blue-black insoluble powder. Scanning electron microscopy (SEM) pictures reveal that the PMPS particles are microspheres with diameters ranging from 1.3 - 4 micrometers (distribution peaking at 1.9 micrometers). The absorption capacity values of PMPS particles were studied for a large majority of the elements in the periodic table in order to establish a pattern or trend in absorption. The elements specifically targeted at the beginning of the research were the biological elements vital to sustain life and the heavy metals that pose a threat to the environment via pollution and poisoning. Fifty-four elements were investigated in total and all absorbed in varying amounts ranging from 0.01 mmol/g for caesium up to 5.66 mmol/g for phosphorous. It was found that varying the initial elemental compound, temperature and solvent concentrations vastly altered the amount of element absorbed. The majority of elements absorbed best when dissolved in hot concentrated hydrochloric acid at 50oC, some preferred cold conditions (4oC) and/or a neutral solvent (water). The freshness of the elemental compound had a huge impact on the absorption capacities, i.e. new compounds absorbed much better than old stock. A comparison between chloride salts and the hydroxides of Group 1 alkali metals revealed that the hydroxides absorbed much better than the salts, sometimes with more than a ten-fold increase. Release profiles were studied for PMPS particles containing eleven different elements when subjected to an aqueous medium. The study focused on some of the elements that are commonly utilised in industry and also the soft acids and bases primarily because they had some of the highest sorption values and the fact that the majority are known to be particularly toxic to man. The amount of ions released varied enormously ranging from 0% release for selenium up to 83% for arsenic. It was interesting to observe that arsenic had the highest percentage release despite having the lowest sorption uptake and selenium had the lowest (zero) percentage release despite having one of the highest sorption uptakes. Analysis of the release data revealed that there appears to be two types of profile emerging. In the first type of profile the metallic ions leached out of the PMPS particles slowly over a period of time until equilibrium was reached whereupon no more ions were released. This happened for the arsenic, copper, lead, mercury, cadmium, silver and gold ions. In the second type of profile all of the free ions were released as soon as water was added, in the first 2 mL aliquot. This happened for the manganese, sodium and caesium ions. It would appear that the ions that have the gradual release profile are the heavier ions on the right hand side of the periodic table, which also means that they are soft acids or bases. The ions that have the second type of profile, where release was achieved in the first aliquot are situated on the left hand side of the periodic table and were all found to be hard acids. Over-coating studies using PMPS particles containing copper and sodium were separately investigated. The results revealed that PMPS-Cu particles when overcoated with a polymer do appear to have a slow release profile.

This paper analysis the cost-utility, measured in cost per QALY gained, of impact absorbent flooring that reduce hip fractures among institutionalized elderly in comparison to standard flooring. The study is based on experimental data from an elderly institution, where the absorbing floor was installed in 2010. Using a decision tree, the costs and benefits related to the new flooring are calculated on a one year basis, resulting in an incremental cost per QALY of 713327 SEK for the base case. Although the experimental data shows that there is an impact of the new flooring in reducing hip fractures a conclusion whether the policy is cost-effective or not can hardly be drawn. Sensitivity analysis based on a simulation of 5000 cases suggests that the result is robust. / Effektsamband i Samhället

Höftfrakturer är ett stort problem för äldre i dagens samhälle och för samhället i stort. Många drabbas vilket leder till stort lidande och för samhället höga kostnader. Detta har Professor Peter Apell vid Chalmers University of Technology uppmärksammat. Han har startat upp flera projekt inom området Innovative textiles in healthcare för att hitta nya och bättre lösningar på problem relaterade till vård och hälsa. Det här projektet är ett av de projekt som uppkommit genom hans engagemang. Projektets fokus har varit att undersöka dämpning och spridning av kraft samt energiupptagningsförmåga hos tredimensionell väv i kombination med non woven. Samma typ av undersökning har utförts på ett polymert material kallat D3O. D3O används i nuläget i viss typ av skyddsutrustning men inte inom området höftskydd för äldre. De olika materialens egenskaper har därefter jämförts. Intresset för att undersöka 3D-textil i sammanhanget skyddsmaterial är grundat i att det kan ha flera fördelar i förhållande till de material som används i befintliga skydd idag. Många höftskydd på marknaden har skumgummi som skyddsmaterial. En fördel med textila skydd är möjligheten att producera skydd och hållare för skyddet i ett och samma material vilket förenklar framtida återvinning. Med textila skyddspaneler finns även möjligheten att framställa lätta och flexibla skydd för ökad komfort. Projektets största begränsning har varit testutrustning och testmetoder, en begränsning för hela industrin inom utveckling av höftskydd. Den testutrustning som använts i projektet har varit en fallrigg med tillhörande fallkropp i form av en kula, hos företaget Industritextil Job i Kinna, samt två olika dragprovare med speciellt framtagna hållare och klämmor vid Textilhögskolan i Borås. De textila konstruktionerna som undersökts under projektet har framställts av författarna med hjälp av maskiner och textila material som varit tillgängliga på Textilhögskolan. Flera bindningar togs fram, dessa vävdes och studerades. Två varianter av distansvävar med stående distanser ansågs ha potential tillsammans med två olika konstruktioner av non woven. D3O-materialet köptes in i form av färdiga höftskydd. Projektet har resulterat i att de konstruktioner som tagits fram i väv och non woven har potential men i nuläget troligtvis inte tar upp tillräckligt mycket av kraften för att undvika en frakturskada. Undersökningen har dock visat att det finns mycket att utveckla och forska vidare på inom området 3D-textil. Det polymera skyddet D3O visade goda resultat teoretiskt och praktiskt i den utsträckning det kunde undersökas med tillgänglig testutrustning. Mer arbete med utformning av materialet rekommenderas för att ta fram ett skydd som är bra ur både komfort- och funktionssynpunkt. Det krävs ytterligare tester med bättre anpassad testutrustning innan skyddseffekten kan bekräftas vara tillräcklig. / Hip fractures are a big problem for the elderly in today's society and a problem for our society as a whole. A lot of people get affected by it and it leads to suffering and a large cost for society. This is something Professor Peter Apell at Chalmers University of Technology has noticed. He has started several projects within the field of Innovative textiles in healthcare to find new and improved solutions to issues related to health and welfare. This project is one of the projects started because of his commitment to the cause. The focus of the project has been to explore the attenuation of force, dispersion of force and energy absorption of distance weaves in combination with non woven materials. The same type of exploration has been applied to a polymer material called D3O. D3O is already being used in some types of protective gear but not within the area of hip protection for the elderly. The different materials characteristics have thereafter been compared. The base of the interest in exploring 3D textile protection is that it could provide certain advantages which some of the hip protection products of today lacks. Many of the products today use foam rubber as the base of protection. An advantage with protective panels made by textiles is the possibility that the whole of the protective product can be made in one and the same material throughout which will simplify future recycling. Another advantage with textile protective panels is the possibility of light and flexible constructions for increased comfort. The most influential restriction to the project has been equipment for performing tests on the materials, which is a big restriction in the whole business of developing hip protection. The testing equipment used in this project has been a setup for performing drop testing with a cylindrical impact body, at the company Industritextil Job in Kinna, and two different tensile machines with specially made clamps at the University of Borås. The textile constructions examined during the project has been manufactured with the use of machines and materials available at the Swedish School of Textiles at the University of Borås. Different weaves were constructed, produced and studied. Two of the three dimensional weaves were regarded as having potential if combined with two different non woven structures. The D3O material was bought, readymade, in the form of hip protection panels. The project has shown that the contextures produced have potential but as of now probably is not enough to protect the hip from fracturing. They did show that there is a lot to explore further within the area of 3D-textiles. D3O, showed good results theoretically and practically to the extent possible to test with the available equipment. More work is advised concerning the shape of the protection panel to make it comfortable and effective in its protection. Further testing with other more adapted testing equipment is required before it can be said with certainty that the protective panel reduces applied forces enough for it to avoid a fractured hip.

Ces travaux de thèse consistent à formuler des nanocomposites électriquement conducteurs pour des applications micro-ondes. L’objectif principal est la mise en œuvre de matériaux absorbant les ondes radar, plus particulièrement sur la bande X (8-12 GHz). La polyaniline et les nanotubes de carbone, dispersés dans une matrice époxyde, ont été sélectionnés pour apporter les propriétés d’absorption aux fréquences visées. Différentes morphologies de polyaniline ont été synthétisées afin d’étudier leur influence sur les propriétés d’absorption des composites. L’utilisation d’une polyaniline à morphologie feuillet, présentant une forte anisotropie et un facteur de forme élevé, permet d’augmenter la conductivité et les pertes diélectriques des composites. De plus, leur association avec des nanotubes de carbone améliore significativement les propriétés d’absorption aux fréquences micro-ondes. Des écrans absorbants radar performants qui présentent des coefficients de réflexion inférieurs à -20 dB ont pu être modélisés et mis en œuvre, confirmant le potentiel de ces matériaux pour des applications de furtivité radar. / This thesis deals with the formulation of electrically conductive nanocomposites for microwave applications. The main purpose is to process radar-absorbent materials, more particularly at the X band. (8-12 GHz). Polyaniline and carbon nanotubes, dispersed in an epoxyde matrix, have been selected. Different morphologies of polyaniline have been synthesized to study its impact on the absorption properties of composites. Using flake-like polyaniline showing high anisotropy and aspect ratio increases conductivity and dielectric losses of composites. Moreover, its association with carbon nanotubes significantly improves the absorption properties at microwaves frequencies. Efficient radar absorbing screens, showing reflection losses lower than -20 dB, have been calculated and processed confirming the potential of these materials for stealth applications.

Syftet med arbetet är att få en förståelse för moss-sedumtakets bullerdämpande egenskaper. Jag kommer även att försöka förutsäga med hjälp av akustikteori vilken utav de två olika uppbyggnadssystemen av moss-sedumtak som ger den bästa bullerdämpande effekten. Mätningarna kommer att bestå i att registrera ljudtrycksnivån i rummet, vid varje oktavband i frekvensområdet 125-4000 Hz. Först utan moss-sedummattan och sedan med moss-sedum mattan. Storleken på differensen i ljudnivån ger en bild av i vilket frekvensområde som ljudabsorptionen är effektivast. För att ytterliggare öka förståelsen för hur moss-sedum absorberar ljud så kommer även absorptionsfaktorn att beräknas. Utifrån resultaten kan man se en tydlig bild på hur xeroflor moss-sedum mattan absorberar i frekvenserna 125-4000 Hz. Den har sin bästa absorption i området 500-4000 Hz och i detta område så är det runt 1000 Hz som den absorberar effektivast.   Om vi tittar på de två olika systemen som Veg Tech använder för att bygga upp ett sedumtak på så sker dämpningen i XMS 0-4 med hjälp av luftspalten och i system XMS 2-27 i VT-filten. Men i detta fall så är luftspalten endast 25 mm så en märkbar ökad dämpning är svårt att föreställa sig. VT-filten som används i XMS 2-27 har öppna celler och kan liknas vid mineralull, som är en bra absorbent. Min slutsats är att 10 mm VT-filt ger bättre dämpning än en luftspalt på 25 mm.

<p></p><p>Syftet med arbetet är att få en förståelse för moss-sedumtakets bullerdämpande egenskaper. Jag kommer även att försöka förutsäga med hjälp av akustikteori vilken utav de två olika uppbyggnadssystemen av moss-sedumtak som ger den bästa bullerdämpande effekten.</p><p>Mätningarna kommer att bestå i att registrera ljudtrycksnivån i rummet, vid varje oktavband i frekvensområdet 125-4000 Hz. Först utan moss-sedummattan och sedan med moss-sedum mattan. Storleken på differensen i ljudnivån ger en bild av i vilket frekvensområde som ljudabsorptionen är effektivast. För att ytterliggare öka förståelsen för hur moss-sedum absorberar ljud så kommer även absorptionsfaktorn att beräknas. Utifrån resultaten kan man se en tydlig bild på hur xeroflor moss-sedum mattan absorberar i frekvenserna 125-4000 Hz. Den har sin bästa absorption i området 500-4000 Hz och i detta område så är det runt 1000 Hz som den absorberar effektivast.</p><p> </p><p>Om vi tittar på de två olika systemen som Veg Tech använder för att bygga upp ett sedumtak på så sker dämpningen i XMS 0-4 med hjälp av luftspalten och i system XMS 2-27 i VT-filten. Men i detta fall så är luftspalten endast 25 mm så en märkbar ökad dämpning är svårt att föreställa sig. VT-filten som används i XMS 2-27 har öppna celler och kan liknas vid mineralull, som är en bra absorbent. Min slutsats är att 10 mm VT-filt ger bättre dämpning än en luftspalt på 25 mm.</p><p> </p>

Diss. (sammanfattning) Umeå : Univ., 2007. / Härtill 4 uppsatser.

Orientadores: Paulo César Giraldo, Angélica Espinosa Barbosa Miranda / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T14:22:13Z (GMT). No. of bitstreams: 1 Piassarolli_VirginiaPianessole_D.pdf: 3263446 bytes, checksum: f4dd848409151c430a17771f37ef8dd8 (MD5) Previous issue date: 2014 / Resumo: A higiene é o conjunto de cuidados corporais, do ambiente e de um modo de viver, de se vestir e de habitar para evitar doenças com o objetivo de conservar e fortificar a saúde. Em se tratando de saúde genital, a relação não poderia ser outra, uma vez que esta é parte integrante e inseparável da saúde geral do indivíduo. Estas ações são dependentes da condição social da população e previnem complicações e desconfortos, especialmente na área genital feminina, porém ainda não foram bem estudadas. Objetivo: Avaliar hábitos de higiene e cuidados com a genitália de mulheres no menacme e associá-los com fatores sociodemográficos. Sujeitos e Métodos: Foi realizado um estudo de corte transversal de base populacional, por amostragem, em todas as 28 Unidades de Saúde de Vitória, Espírito Santo, Brasil. Foram incluídas aleatoriamente 474 mulheres, admitidas em seus domicílios, no período de Julho de 2012 a Dezembro 2013. Um questionário auto-respondido foi preenchido de maneira sigilosa contendo 56 perguntas relacionadas ao tema, divididas nos seguintes domínios: I ¿ Limpeza genital; II ¿ Uso de absorventes higiênicos; III ¿ Práticas depilatórias; IV ¿ Uso de piercings e tatuagens genitais; V ¿ Tipo de Indumentária e VI ¿ Práticas sexuais. Além das variáveis relacionadas à higiene, foram considerados fatores sociodemográficos como idade, nível de escolaridade e renda familiar mensal, e algumas variáveis clínicas. A análise dos dados empregou o teste exato de Fisher para averiguar associação entre as variáveis; e regressão múltipla logística para verificar a chance de complicações clínicas e ginecológicas. O nível de significância considerado foi p<0,05. Resultados: A média da idade das participantes foi de 31 anos (± 7,7), 54% eram não caucasianas, casadas ou com parceiros (56,8%), com renda familiar inferior a R$ 1500,00 (53,7%) e 69,6% haviam cursado até o Ensino Médio. As análises sobre os hábitos de higiene demonstraram que 57,4% das mulheres tomavam dois banhos por dia, entretanto 51% lavavam a vulva mais de três vezes ao dia. O uso de lenços umedecidos foi relatado por 13,5% e somente 17,9% das entrevistadas realizavam corretamente a higiene após evacuação. Ducha vaginal foi descrita por 47% dos casos, quase 20% faziam esfoliação na região vulvar e 44,5% relataram corrimento vaginal frequentemente. O uso frequente do protetor diário ocorreu em 38,9% da população, entretanto somente 40,7% destas usavam o protetor sem película plástica. Mulheres mais jovens (p<0,0001) e com maiores níveis de escolaridade (p=0,0390) usavam menos absorventes internos. Observou-se que quanto maior a troca diária do número de absorventes durante o período menstrual, menor foi a chance de aparecimento de fissuras como complicação [OR=0,11 (IC95%:0,02-0,48)]. Quanto ao uso de vestimentas, o tipo de calcinha menos utilizada foi a sintética (5,5%) e os modelos fio dental ou tanga foram os mais relatados (68,6%), principalmente entre as mais jovens (p<0,0001). Cerca de metade da amostra referiu o uso frequente de calças apertadas (51,1%), o que esteve associado às mulheres jovens (p=0,0002) e com maior nível de escolaridade (p=0,0173), além de ser uma variável que identificou uma chance quase duas vezes maior do aparecimento de corrimento vaginal relatado pelas participantes [OR=1,95 (IC95%:1,35-2,81)]. Verificou-se que 97,9% das mulheres realizavam depilação íntima e 65,4% acreditavam ser importante para higiene. Em geral, mulheres com baixa escolaridade e renda utilizavam a lâmina de barbear como principal método. A depilação genital de forma "completa" foi relatada por 52,1% das participantes. Conclusão: Os hábitos de higiene e cuidados com a genitália ainda são inadequados em um percentual muito elevado de mulheres brasileiras. Fatores sociodemográficos como idade, nível de escolaridade e renda familiar mensal associaram-se com diversos aspectos na prática destes hábitos / Abstract: Hygiene is the set of body care, of the environment and a way of living, dressing and inhabits to prevent diseases with the goal of preserving and strengthening the health. In terms of genital health, the relation could not be different, since this is an integral and inseparable part of the overall individual health. These actions are dependent on the social status of the population and prevent complications and discomfort, especially in the genital area, but have not been well studied. Objective: To evaluate hygiene and care genitalia among women in menacme and associate them with sociodemographic factors. Subjects and methods: A population-based study was conducted, by sampling at all 28 health units in Vitoria, Espirito Santo, Brazil. Randomized 474 women were included, admitted in their homes between July 2012 to December 2013. A self-administered questionnaire was completed confidentially containing 56 questions related to the subject, divided into the following areas: I - Genital cleaning; II - Use of sanitary pads; III - Depilatory practices; IV - Use of genital piercings and tattoos; V -Clothing type and VI - Sexual practices. Apart from hygiene-related variables were considered sociodemographic factors such as age, education level and monthly family income, and some clinical variables. Fisher Exact Test was used to assess associations between variables; and multiple logistic regression to verify the chance of gynecological and clinical complications. Significance level was set at p <0.05. Results: The average age of participants was 31 years (± 7.7), 54% were not caucasian, married or had partners (56.8%), with family income less than R $ 1500.00 (53.7%) and 69.6% had attended high school. Analyses of hygiene habits showed that 57.4% of women took two baths per day, however 51% washed the vulva more than three times daily. The use of wet wipes was reported by 13.5% and only 17.9% of respondents performed correctly hygiene after defecation. Vaginal douching was reported by 47% of cases, almost 20% did exfoliation in vulvar region and 44.5% reported vaginal discharge frequently. The frequent use of the panty liners occurred in 38.9% of the population, however only 40.7% of these used without plastic layer. Younger women (p<0.0001) and with higher levels of education (p = 0.0390) used less tampons. It was observed that the greater the number of daily change of the absorbent during the menstrual period, the lower chance of appearance of fissures as genital complication [OR=0.11 (CI95%:0.02-0.48)]. Regarding the use of clothes, the type of underwear was less synthetic (5.5%) and the models thong or string were the most common (68.6%), especially among the youngest (p<0.0001). Approximately half of the sample reported frequent use of tight pants (51.1%) which was associated with young women (p=0.0002) and higher educational level (p=0.0173), as well as being a variable which identified almost twice the chance of appearance of vaginal discharge reported by participants [OR=1.95 (CI95%:1.35-2.81)]. It was verified that 97.9% of women performed pubic hair removal and 65.4% did because they believe it is important for hygiene. Generally, the razor blade was the main method used by women with low education and income. The "complete" genital hair removal was related by 52.1% of participants. Conclusion: Hygiene habits and genitalia care are still inadequate in a very high percentage of Brazilian women. Sociodemographic factors such as age, education level and monthly family income were associated with several aspects in practice of these habits / Doutorado / Fisiopatologia Ginecológica / Doutora em Ciências da Saúde

Recently, due to the unique properties and structures such as large geometric surface area, electrical conductivity and light weight, 3D structured carbon materials have been attracting extensive attention from scientists. Moreover, the materials, which can provide well-defined pathways for reactants to easily access active sites, are extremely useful for energy conversion as well as environmental and catalysis applications. To date, many precursors have been used for fabrication of 3D structured carbon materials including pitch, carbon nanotubes, graphene, and polymer foams. This thesis, as shown in the thesis title, focus on two main aspects: the study of the characteristics of melamine based carbon foam synthesized at different conditions and their applications. In paper I, it was revealed that through a simple, one-step pyrolysis process, flexible carbon foam synthesized from melamine foam (BasotectÒ, BASF) was obtained. Additionally, through a pyrolysis-activation process, activated carbon foam which possesses hydrophilic nature and high surface area was successfully synthesized. The characteristics of carbon foam such as the hydrophobic/hydrophilic nature, electrical conductivity, mechanical properties and surface chemistry were studied. It was shown that carbon foam could be successfully used as an absorbent in environmental applications e.g. removing of spill oil from water (paper I) or as support for heterogeneous catalysts, which in turn was used not only in gas phase reactions (paper I and IV) but also in an aqueous phase reaction (paper II). Importantly, when combined with a SpinChem® rotating bed reactor (SRBR) (paper II), the monolithic carbon foam/SRBR system brought more advantages than using the foam alone. Additionally, the work in paper III showed the potential of carbon foam in an energy conversion application as anode electrode substrate in alkaline water electrolysis. In summary, the versatility of the carbon foam has been proven through abovementioned lab scale studies and due to the simple, scalable and cost effective pyrolysis and activation processes used for the production, it has potential to be used in large-scale applications.

Este trabalho relata o uso de polpa etanol /água de medula em um estudo que visa obter e caracterizar carboximetilcelulose substancialmente insolúvel, destinada a aplicação como material absorvente. Em um experimento típico a reação de carboximetilação de polpa etanol / água branqueada de medula de bagaço foi realizada em suspensão de isopropanol /água de 1: 8 (mim) a 80&#176C por 4 horas empregando relação molar de celulose / hidróxido de sódio / ácido monocloroacético de 1 /5.4 / 8.8. Os produtos foram caracterizados quanto à presença de grupos funcionais característicos; grau médio de substituição (DS); solubilidade em água e em solução aquosa alcalina; capacidade de retenção de água e de solução salina; morfologia e estabilidade térmica. As técnicas instrumentais empregadas nessas caracterizações incluem as espectroscopias de ressonância magnética nuclear (RMN) e de infravermelho (i.r); microscopia eletrônica de varredura (MEV); termogravimetria (ATG) e calorimetria diferencial de varredura (DSC). O material com melhores características foi obtido quando a condição acima descrita para a reação de carboximetilação foi aplicada e corresponde a um produto muito pouco solúvel (SH20 < 2%) com características absorventes superiores às da matéria-prima. Foram realizadas outras oito sínteses empregando diferentes concentrações de ácido monocloroacético e outros tempos de reação. Todos os produtos apresentam o efeito polieletrólito, mas suas capacidades de inchamento não dependem de forma simples dos graus médios de substituição. As capacidades de\' retenção de água apresentadas pelos produtos deste trabalho parecem resultar de um compromisso entre variáveis da reação, quantidade e distribuição de grupos iônicos ao longo das cadeias e grau de intercruzamento. Nossos resultados não permitem concluir se os materiais correspondem a cadeias poliméricas intercruzadas física ou covalentemente, pois a ocorrência de ligações de intercruzamento do tipo éster não pode ser descartada, mas a confirmação de sua presença por espectroscopia de infra-vermelho é prejudicada pela extensa superposição de bandas na região de interesse. Apesar do emprego de fontes convencionais de celulose em condições semelhantes de síntese resultar em produtos com características muitos superiores àquelas apresentadas pelos produtos deste trabalho, consideramos que nossos resultados são promissores. Por um lado, devem ser consideradas a disponibilidade e abundância da matéria-prima que podem significar um custo relativamente baixo quando comparado ao de fontes convencionais de celulose. Por outro lado, o emprego de polpas de bagaço em lugar de madeiras pode ter um impacto ecológico muito positivo dada a possibilidade de preservação de reservas florestais. Finalmente é necessário ressaltar que a qualidade dos produtos obtidos depende das características da matéria-prima empregada, principalmente grau de polimerização da celulose obtida por polpação. Nesse sentido, o emprego de outros processos de polpação e branqueamento que reduzam a degradação das cadeias de celulose melhorarão as características das polpas de medula e, por consequência, as propriedades absorventes da carboximetilcelulose insolúvel obtida. / This work describes the use of ethanol / water pulps of pith in a study aiming the obtention and characterization of substantially insoluble carboxymethylcellulose for application as an absorvente material. In a typical experiment the carboxymethylation reaction of bleached ethanol / water pulp occurred at 80&#176C for 4 hours in isopropanol/ water suspension 1 : 8 (w/w) employing a cellulose / sodium hydroxide / monochloroacetic acid molar ratio of 1.0/5.4 / 8.8. Characterizations were made through the determinations of the presence of characteristic functional groups; degree of substitution (DS); solubility in pure water and alkaline aqueous solution; water and saline aqueous solution retention capacity; morphology and thermal stability of the obtained products. Infra-red (i.r.) and nuclear magnetic ressonance (NMR) spectroscopies; scanning electronic microscopy (SEM); thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were employed for these characterizations. The material with the best absorbent characteristics was obtained through the application of the condition above described for the carboxymethylation reaction. This is a very insoluble product (S IDO < 20/0) with a much higher water retention capacity than unreacted pulp employed as raw material. Other eight products were prepared through the application of different concentrations of monochloroacetic acid and variable reactions times. AlI products manifested the polyelectrolyte effect, but their water retention capacities seem to depend on the degree of substitutions in a complex way. Water retention capacities of the products of this work seem to be the result of a compromise among the parameters of the carboxymethylation reaction, the content and distribution of ionic groups and the degree of crosslinking. From our results it cannot be concluded if the materials correspond to physically or covalently crosslinked polyffiericchains since the occurrence of ester bonds as crosslinkers can not be discarded, but its detection in the infra-red spectra is difficult as a consequence of the extensive superposition of bands in the region of interest. Although the use of conventional sources of cellulose in conditions similar to those described here result in products of superior quality we believe that pith can be a good altemative raw material for the obtention of carboxyffiethyl ceIlulose with absorbent characteristics. In Brazil it is available as a very abundant and low cost raw material derived from the industries which process sugar cane for the production of ethanol and sugar and its utilization in place of wood pulps may also represent ecological advantages as forest preservation will be favoured. Finally it is worthwhile to remember that the quality of the products also depends on the raw material characteristics, mainly the degree of polyffierization of the cellulose obtained after pulping. So the use of the other pulping and bleaching processes which minimize chain degradation wiIl certainly result in better pulps from pith and as a consequence materials with better absorbent characteristics will be prepared.