Modulus Of Paper Research Articles

J0407-1-3 竹単繊維を用いて抄紙する紙の比剛性に及ぼす竹齢の影響(バイオマス由来材料の成形加工と特性評価(1))

J0407-1-3 竹単繊維を用いて抄紙する紙の比剛性に及ぼす竹齢の影響(バイオマス由来材料の成形加工と特性評価(1))

Contactless measurement of the elastic Young's modulus of paper by an ultrasonic technique

The use of a non-contact ultrasonic technique for the characterization of the in-plane elastic Young's moduli of paper is considered. The determination of these moduli from A 0 (fundamental antisymmetric plate wave mode) measurements, using the empirical technique introduced by Luukkala et al. (1971), is discussed: it is shown that the common low frequency approximation is not valid for paper, owing to its orthotropic structure. Numerical simulations are used to evaluate the validity domain of Luukkala's method. A new device was developed, and Young's moduli of various paper sheets were determined from A 0 measurements. These moduli values were found to be in good agreement with those measured using a common laboratory contact ultrasonic technique.

Model for the Moisture Quenching of Solid-Matrix Phosphorescence via the Young's Modulus of Filter Paper

Experimental Young's modulus values were obtained as a function of adsorbed moisture content for filter paper samples with no absorbed salt and with several different types of salt adsorbed on filter paper. The Young's modulus values were correlated with the room-temperature phosphorescence intensities and room-temperature phosphorescence lifetimes of several phosphors adsorbed on filter paper samples with the use of a theory for the Young's modulus of paper and solid-matrix phosphorescence quenching concepts. Phosphorescence intensity ratios changed much more dramatically than phosphorescence lifetime ratios, both with increasing moisture uptake on the filter paper and with decreasing modulus ratio of the filter paper samples. The changes in the phosphorescence parameters, due to the adsorption of moisture on filter paper, were caused primarily by alterations of the hydrogen-bonding network in the amorphous regions of filter paper.

Experimental evaluation of the specific young's modulus of paper.

The specific Young's modulus, Es/(ρs/ρf), was introduced to experimentally evaluate the effectiveness of the stress transfer factor of interfiber bonding in handmade pulpsheet. As a result of the application of this modulus to calendered sheet, no additional interfiber bonding was proved to be formed, although the Young's modulus calculated by the conventional method increased with decreasing thickness. Dimension of the specific Young's modulus, Pa, provides a logical approach in mechanical discussion of paper. A further investigation is needed to study the quantitative treatment of the elastic properties of paper.

引張り試験からの紙のヤング率の実験的算出法

Young's modulus from a conventional elongation test of paper is usually underestimated, mainly because slippage occurs between the specimen and the grips during loading. A more accurate Young's modulus is sometimes required for a precise discussion of paper science or the suitable material design of paper. Although the vibrating reed method and the ultrasonic method have both been proposed for determining Young's modulus of paper, these techniques are limited by the requirement of special devices and a complicated measurement procedure. Therefore, a modified calculation method for Young's modulus from the elongation test is discussed in this study.The apparent deformation (Δd) of paper in a conventional elongation test can be divided into two parts, a real sheet deformation (Δf) and a false deformation which includes the slippage (Δs). The percentage of Δs of the apparent strain becomes larger as span 1 decreases, because for a certain kind of paper at a certain external loading level Δs is considered to be the same regardless of test span. The amount of Δs at a given load can be obtained by extrapolating the relationship between apparent deformation at the load level and test span to zero span. Thus, Young's modulus can be calculated after the correction of sheet strain by the value of Δs.The effect of restraint of lateral contraction near the grips on extensional rigidity was found to be small when calculated by the finite element method, provided that the span is more than twice the sample width. The results suggest that the specimen span should be more than 30 mm.Young's modulus corrected in this way was fairly close to that obtained from the vibrating reed method.

A theory for the elastic modulus of paper

A review has been made of the previous attempts to formulate a theory for the elastic modulus of paper in terms of fibre properties. The suggestion is made that, by considering the case of uniaxial stress, previous authors have attempted a problem that is too complex for the present state of knowledge. It is suggested that the case of equal biaxial strain is theoretically simpler and that verification of such a theory can be made more reliably. The biaxial theory is developed and the elastic modulus is written in terms of the moduli of the fibres and the bonded area of the sheet. The biaxial modulus has been measured for three levels of fibre bonded area for one pulp and these admittedly sparse data are in agreement with the theory.