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The influence of paper surface sizing on inkjet
Costa, Tiago G.; Gamelas, José A.; Moutinho, Isabel M.; Figueiredo, M. Margarida; Ferreira, Paulo J.The effect of paper surface sizing on inkjet pigment penetration was evaluated by studying four different paper samples: one taken as reference, without surface sizing (paper RP), one surface sized with cationic starch (RPS1), one with a mixture of cationic starch and poly(styrene-co-maleic anhydride) (RPS2), and one with a mixture of cationic starch and poly(styreneco- acrylate) (RPS3). Assessment was based on...
Application of FT-IR-ATR Spectroscopy to Evaluate the Penetration of Surface Si...
Ferreira, Paulo J.; Gamelas, José A.; Moutinho, Isabel M.; Ferreira, Ana G.; Gómez, Nuria; Molleda, Cristina; Figueiredo, M. MargaridaIt is widely recognized that the surface properties of paper depend on the fibrous matrix and the final surface treatment applied to the paper. Regarding chemical paper surface treatments, an important issue is the evaluation of the penetration of chemical compounds into the fibrous matrix, as the chemicals can potentially cause changes in the intrinsic properties of paper. The work presented here aimed to use ...
Rheological Study of Genipin Cross-Linked Chitosan Hydrogels
Moura, M. José; Figueiredo, M. Margarida; Gil, M. HelenaThis paper reports the rheological behavior of chitosan solutions that have been cross-linked with different amounts of genipin, at body temperature and physiological pH. The effect of the cross-linker loading on the rheological properties of hydrogels has been evaluated. The oscillatory time sweep method was used to monitor the dynamic viscoelastic parameters during in situ (i.e., in the rheometer) gelation ex...
A comparative study of two automated techniques for measuring fiber length
Carvalho, M. Graça; Ferreira, Paulo J.; Martins, Alexandre A.; Figueiredo, M. MargaridaMeasurements from two automated fiber analyzers—Kajaani FS-200 and Galai CIS-100—are compared.The FS-200 measures fiber length and coarseness via an indirect optical method.The CIS-100 measures fiber length and width by analyzing video images of fibers. Length-weighted average fiber lengths for the FS-200 were 10–20% lower than those for the CIS-100. Reference measurements from microscopic image analysis sugges...
Calculating Shape Factors from Particle Sizing Data
Barreiros, Fátima M.; Ferreira, Paulo J.; Figueiredo, M. MargaridaIt is well established that particle size and shape substantially influence the bulk properties of powdered materials. Although these characteristics are closely interrelated, the tendency has been to analyse the particle size independently from particle shape. The aim of this work was the assessment of particle shape through particle sizing data. For this purpose, three different particle shape materials - gla...
Mass Calibration of the Coulter Counter Model ZM
Figueiredo, M. Margarida; Rasteiro, M. Graça; Santos, Cristina; Monteiro, CristinaThe calibration of electrical sensing zone instruments is normally achieved by using spherical particles with a certified size. An alternative and more fundamental procedure, known as mass or self-calibration, is to use particles of the material under test.This work concerns the mass calibration technique, in particular the equations used to calculate the mass calibration constant. It is demonstrated that some ...
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