How much weighs the swelling pressure

Abstract

We are presenting a new method to study the swelling of gels by following the apparent weight increase during confined swelling. This method, compared to other procedures, is characterized by its simplicity and versatility to study the influence of the experimental conditions such as composition of the swelling agent and temperature. Examples are given for poly(acrylic acid) and poly(N-isopropyl acrylamide) hydrogels and the influence of ethanol content, pH, and temperature in the water pool.

Studies on swelling of wood with water and ionic liquids

“…The weighing method as described recently (Höhne and Tauer 2014) is an easy to use and versatile tool to study the swelling behavior of wood. The measuring system is open, and hence, during the measurements the composition of the swelling agent can be changed without interrupting the data recording.…”

“…(1). For a discussion of the relation of this method to study swelling of polymeric gels to other methods, the reader is referred to a former publication (Höhne and Tauer 2014). For the data evaluation, one should always consider that the chemical composition of wood fluctuates not only from species to species but for a given species with the particular conditions of growth (nature of soil and climate) and even along a single tree (Pettersen 1984).…”

“…It should be noted that in contrast to polymer gels where the samples must be confined in a container with walls permeable only for the swelling agent (Höhne and Tauer 2014), the wood pieces were used without confinement. Due to the firmness of the wood, isochoric conditions are preserved to a great deal; at least the small changes that happen do not limit the meaningful conclusions of the measurements.…”

“…The readout of the balances (Entris 6202-1S or Practum 5101-1S both from Sartorius, Germany) was transferred and continuously recorded with the MultiControl software on a computer. Details of the measurements applied to polymeric gels have been recently communicated (Höhne and Tauer 2014). Two different constructions were used for the fixation of the wood sample on the weighing pan.…”

“…Results are presented with respect to the interaction of spruce and beech wood with water, ILs, and mixtures of both using a recently described experimental procedure to follow the swelling behavior of synthetic polymer gels (Höhne and Tauer 2014). This experimental method is different to the classical experimental techniques following the interaction of wood with solvents which have been developed over the years such as following the dimensional changes by size measurements (Mantanis et al 1994a(Mantanis et al , b, 1995a or changes in the wood cells by X-ray tomographic investigations (Derome et al 2011;Patera et al 2013) and microscopic studies (Kanbayashi and Miyafuji 2013, 2015Miyafuji and Suzuki 2012).…”