10 documents found, page 1 of 1
Cellulose micro and nanofibrils as coating agent for improved printability in o...
Lourenço, Ana F.; Gamelas, José A. F.; Sarmento, Pedro; Ferreira, Paulo Jorge TavaresThe use of nanocelluloses is being conducted for the most diverse applications. Their performance as coating agent has been mainly explored to improve barrier properties, as they emerge as perfect candidate for plastic substitution, but it is also important to explore their potential to improve printing quality. In the present work, the influence of different nanocelluloses, obtained through mechanical, enzymat...
On the toxicity of cellulose nanocrystals and nanofibrils in animal and cellula...
Ventura, Célia; Pinto, Fátima V.; Lourenço, Ana Filipa; Ferreira, Paulo Jorge Tavares; Louro, Henriqueta; Silva, Maria JoãoThe need for reaching environmental sustainability encourages research on new cellulose-based materials for a broad range of applications across many sectors of industry. Cellulosic nanomaterials obtained from different sources and with different functionalization are being developed with the purpose of its use in many applications, in pure and composite forms, from consumer products to pharmaceutics and health...
Influence of initial chemical composition and characteristics of pulps on the p...
Ehman, N V; Lourenço, A. F.; McDonagh, B H; Vallejos, M. E.; Felissia, F.E.; Ferreira, Paulo Jorge Tavares; Chinga-Carrasco, G.; Area, M. C.This work aimed to study the influence of the initial chemical composition (glucans, lignin, xylan, and mannans), intrinsic viscosity, and carboxylate groups of pulps on the production process and final properties of lignocellulosic nanofibers (LCNF). Pulps of pine sawdust, eucalyptus sawdust, and sugarcane bagasse subjected to conventional pulping and highly oxidized processes were the starting materials. The ...
A comprehensive study on nanocelluloses in papermaking – the influence of commo...
Lourenço, Ana F.; Gamelas, José A. F.; Sarmento, Pedro; Ferreira, Paulo Jorge TavaresNanocelluloses are being explored and produced at an impressively increasing pace. Due to their good characteristics as reinforcement agent, their application in the most diverse fields has proven to be very beneficial. Their use in papermaking has been investigated in several studies, but the industrial implementation is still in a preliminary stage. In the present study, the influence of nanocelluloses, produ...
Tuning rheology and aggregation behaviour of TEMPO-oxidised cellulose nanofibri...
Alves, L.; Ferraz, E.; Lourenço, A. F.; Ferreira, Paulo Jorge Tavares; Rasteiro, M. G.; Gamelas, J. A. F.The present work intends to study the variations in the rheological properties and aggregation behaviour of TEMPO-oxidised cellulose nanofibrils (CNF) aqueous suspensions, as a function of changes in concentration and systematic changes in the pH, by addition of acids with different anions. It was found that CNF suspensions form strong gels at mass fractions higher than 0.35 % and the gel point is ca. 0.18 %. O...
Nanoceluloses na indústria papeleira: produção, propriedades, caracterização e ...
Ferreira, Paulo Jorge TavaresSumário da Lição apresentada para provas de agregação em Engenharia Química, conforme a alínea c) do artº 5º e a alínea c) do artº 8º do DL 239/2007.
Ciência e tecnologia do papel
Ferreira, Paulo Jorge TavaresRelatório da unidade curricular apresentado para provas de agregação em Engenharia Química, conforme a alínea b) do artº 5º e a alínea b) do artº 8º do DL 239/2007.
Enzymatic nanocellulose in papermaking – The key role as filler flocculant and ...
Lourenço, Ana F.; Gamelas, José A. F.; Sarmento, Pedro; Ferreira, Paulo Jorge TavaresNanocelluloses have been increasingly used in composites since their reduced size, high aspect ratio and stiffness confer great strength to the materials. In papermaking, it has been proved that harsh and expensive chemical pre-treatments to generate nanofibrils, such as TEMPO-mediated oxidation, are not the most favourable and therefore the use of cellulose microfibrils (CMF) have gained extra attention, espec...
Características do papel reprográfico produzido com fibras de eucalipto e suas ...
Mendes, Afonso Henrique Teixeira; Park, Song Won; Almeida, Fábio Sérgio; Ferreira, Paulo Jorge TavaresLike any material made from wood fibers, paper also exhibits dimensional changes as a result of variations in moisture content. This property, called hygroexpansivity, is very important both in the papermaking and in the printing processes. The present work studies the hygroexpansivity of reprographic paper produced with eucalyptus kraft pulp, measuring this property during the process in an industrial paper ma...
Effect of surface sizing on the surface chemistry of paper containing eucalyptu...
Moutinho, Isabel Maria Teixeira; Kleen, Anne Marjatta; Figueiredo, Maria Margarida Lopes; Ferreira, Paulo Jorge TavaresThe effect of different surface sizing formulations on the chemical features of surfaces of the papers produced from Eucalyptus kraft pulp was studied. The surface analysis techniques, electron spectroscopy for chemical analysis and time-of-flight secondary ion mass spec- trometry were applied. An uncoated base paper, the ref- erence material, was sized with blends of cationic starch with either co-acrylonitril...