General formula for hygroexpansion of paper

Uesaka, Tetsu

doi:10.1007/bf00363429

Cited by 50 publications

(58 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result is analogous to a bi-layered beam under thermal expansion, but instead of a thermal strain, this model uses the hygroexpansive strain (ε h ) defined as the ratio between the changes in length to initial length as a function of moisture content (m c ). In certain regions ε h is a linear, and reversible, function of the moisture content [37] described by Equation 2 where β is defined as the hygroexpansion coefficient, and Δm c is the change in the moisture content.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Electrically Activated Paper Actuators

Hamedi

Campbell

Rothemund

et al. 2016

Adv Funct Materials

148

153

View full text Add to dashboard Cite

This paper describes the design and fabrication of electrically controlled paper actuators that operate based on the dimensional changes of that occur in paper when the moisture absorbed on the surface of the cellulose fibers changes. These actuators are called "Hygroexpansive Electrothermal Paper Actuators" (HEPAs). The actuators are made from paper, conducting polymer, and adhesive tape. They are lightweight, inexpensive, and can be fabricated using simple printing techniques. The central element of the HEPAs is a porous conducting path (used to provide electrothermal heating) that changes the moisture content of the paper and causes actuation. This conducting path is made by embedding a conducting polymer (PEDOT:PSS) within the paper, and thus making a paper / polymer composite that retains the porosity and hydrophilicity of paper. Different types of HEPAs (straight, pre-curved, and creased) achieved different types of motions (e.g., bending motion, accordion type motion). A theoretical model for their behavior is proposed. These actuators have been used for the manipulation of liquids, and for the fabrication of an optical shutter.

show abstract

Section: Resultsmentioning

confidence: 99%

“…[37,38] By using Equation 1, and the largest curvature that we measured (0.12 cm -1 ), we calculated ε h = 0.3% for a HEPA with L:W =10:1 (see SI). This value is in agreement with the reported values for the hygroexpansion of paper.…”

Section: Resultsmentioning

confidence: 99%

Electrically Activated Paper Actuators

Hamedi

Campbell

Rothemund

et al. 2016

Adv Funct Materials

148

153

View full text Add to dashboard Cite

show abstract

“…As a result, the shrinking of the whole fiber is assumed to be anisotropic. In order to link the single fiber hygroexpansion to the sheet hygroexpansion, Heyden, Gustafsson [179] and Uesaka [4] introduced stress transfer factors that describe the efficiency of stress transfer in the network. Simulations successfully reproduced the measured hygroexpansion values.…”

Section: Single Fiber Hygroexpansionmentioning

confidence: 99%

“…In all cases, the performance can be influenced by the hygroexpansion of paper. Hygroexpansion is the dimensional change due to fluctuations of the relative humidity of the surrounding atmosphere which affects the moisture content of the paper [4]. Due to hygroexpansion, laminates and labels can separate, wrinkle or curl, the distance between printing fiducial marks can be altered and the noble appearance of metallized paper can be diminished.…”

Section: Introductionmentioning

confidence: 99%

Factors affecting the hygroexpansion of paper

Lindner

2017

J Mater Sci

View full text Add to dashboard Cite

Paper is a widely used packaging material and is nowadays regaining importance, e.g., as bio-based and biodegradable material. Moreover, new technologies such as polymer-fiber composites, printed electronics and the deep drawing of paper are developing. The process stability and also the resulting quality of paper converting processes such as coating, metallization, printing, and the printing of electronics are highly affected by the hygroexpansion of paper. In order to reduce production instability and to choose and develop paper substrates with ideal characteristics, critical parameters need to be known. This paper offers an extensive overview of those parameters, starting at a molecular and microscopic level with the effect of the constituents and morphology of single fibers, before moving on to paper contents, chemical modifications and additives and finally concluding with paper production and fiber network modification. It was found that the major influences are single fiber sorption, inter-fiber contacts, microfibril angle, fiber morphology (length, width, curliness) and fiber orientation. This review gives new ideas and insights for technologists working in research, development and production optimization of paper-based products.

show abstract

“…Nonlinear elastic models, orthotropic elasto-plastic approaches and viscoelastic models have been used for studying bending, buckling, failure, tensile response, and creep and relaxation behavior of paper sheet, see, for example [11,12,13,14,15,16] and [17,18,19,20,21,22,23,24]. The formula for the hygroexpansion of paper has been derived from the hygroexpansion of a single fiber and the efficiency of the stress transfer between fibers in [25]. In the reference [26], the traditional theory for linear thermoelasticity was applied to estimate hygroexpansion strains.…”

Section: Introductionmentioning

confidence: 99%