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In dry-formed polymer-bonded networks of cellulose fibers and in other types of nonwovens, the fiber-polymer joint is considered to be the primary factor determining the ultimate properties of the network structure. In an attempt to develop a model describing the joint failure, the well-known fiber pullout test has been applied to a system consisting of regenerated cellulose fibers and three different polymer matrices: a styrene–acrylate copolymer, poly(vinyl alcohol), and high density polyethylene. For each system, the interfacial bond strength was evaluated. The results are, to some extent, discussed in relation to the mechanical behavior of dry-formed networks bonded with similar polymeric materials. It is suggested that both the interfacial properties and the cohesive strength of the polymer binder are of importance for the mechanical strength of the bonded network.

Paper can be regarded as a network of cellulosic fibres, especially at lower basis weights. When the elastic behaviour of paper sheets is modelled, it is normally essential to know or to assume how the stresses (and strains) are distributed at the fibre level. This article presents an attempt to estimate how the stresses are transferred throughout a simple fibre network using the finite element method (FEM). Attention is mainly focused on the axial fibre stress distribution when the network is uniaxially deformed. The presence of fibre ends is found to induce local stress increases (“stress concentrations”) in the deformed network, which presumably have a bearing on the ultimate properties of the sheet. The influence of the properties of the bonds between crossing fibres on the mechanical properties is also investigated. It is noted that the bond stiffness has no significant effect on the stress transfer between fibres provided that the stiffness is above a critical value. Below this value the stress transfer deteriorates rapidly.