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Heat and moisture treatments were shown to affect restoration of the capillary-porous structure of paper folders that was lost during drying. Thermodynamic functions of cellulose water of hydration were calculated for hydrothermal treatment over broad ranges of time and temperature. The effects of saturated vapor with high state parameters on paper strength were demonstrated. [ABSTRACT FROM AUTHOR]

This article introduces a method to validate heat of sorption measurements from isotherms by comparing them to direct measurements using reaction calorimetry. We have evaluated some frequently used single-temperature isotherm models (BET, GAB) as well as two multi-temperature isotherm equations (Anderson, Heikkilä). It turned out that the isotherm models with better isotherm curve fitting characteristics did not deliver the best results for the heat of sorption. Multi-temperature isotherm models such as the Heikkilä equation are able to deliver good results in terms of modelling the isotherm data and determining the heat of sorption. Single-temperature models fit the isotherm data better than multi-temperature models, but failed to deliver correct values for the heat of sorption. We specifically investigated the heat of sorption at very low moisture content, which is most relevant for paper drying. The resulting heat of sorption curves were analyzed with respect to their saturation behavior, which is expected to occur below BET monolayer moisture. The heat of sorption from the Heikkilä’s model was the only one to show the expected saturation at very low moisture content. [ABSTRACT FROM PUBLISHER]

Abstract: This paper considers calcined paper sludge as an alternative source of metakaolin, an established supplementary cementitious material. Calcination of the sludge generated in the recycling of newsprint paper at 700 °C yields a product with pozzolanic properties. The effects of this recycled metakaolin on the rheology and conduction calorimetry of cement pastes have been studied and compared to the effects of commercial metakaolin. The effects are similar and the results show that calcined paper sludge has the potential to be used as a supplementary cementitious material. This offers a route for utilising this waste material, as an alternative to the increased environmental burden associated with the production of metakaolin from natural kaolinite resources. [Copyright &y& Elsevier]