Cellulose fibers are advantageous reinforcing materials for bio-based composites because of their... more Cellulose fibers are advantageous reinforcing materials for bio-based composites because of their availability and good mechanical properties. Several chemical processes have been developed to turn the native fibers into micro- (MFC) or nanofibrillated (NFC) cellulose fibers. These nanocomponents are believed to even have stronger reinforcing capacity because of surface interaction effects at the nanoscale and formation of a fine web structure. During further processing of fibrillated cellulose in combination with a biopolymer matrix, however, there is evidence of agglomeration due to the hydrophilic nature of the fibers and incompatibility with the polymer matrix. In our approach, surface modification of the micro- and nanofibrillated cellulose is done by the in-situ deposition of hydrophobic nanoparticles onto the fiber surface, allowing to tune the required hydrophobicity of the cellulose additives and to make them compatible with extrusion applications, as demonstrated for PLA biopolymers.
The coefficients of friction and wear rates of thermoset polyester matrix composites with plain w... more The coefficients of friction and wear rates of thermoset polyester matrix composites with plain woven polyester fabric reinforcement were studied during reciprocating sliding under adhesive line contact at 50 to 200 N normal loads and 0.3 to 1.2 m/s sliding velocities. The samples were prepared along different orientations of the fabric relatively to the sliding surface and sliding directions, including 0°, 30°, 45°, 60° and 90° in-plane directions and thickness z direction. The coefficients of friction and wear rates were maximum along 90° and minimum along 45° for pure and polytetrafluoroethylene-filled composites. For the latter, overload conditions were minimized, and friction and wear became low for perpendicular fabric orientations. Although sliding is controlled by solid lubrication of polytetrafluoroethylene, the fiber orientations remain dominating the friction under mild sliding conditions. The differences between friction properties along weft and warp orientations could be correlated with mechanical properties along those directions. However, a systematic study in parallel with interpretation of the thermal heating could provide better insights in dry sliding properties. By considering the effects of thermal heating, thermo-mechanical sliding conditions in the interface controlled self-lubricating properties of polytetrafluoroethylene. The wear mechanisms along 0° and 90° directions were mainly determined by the fabric reinforcement, and the sliding along off-axis 45° and thickness directions was mainly controlled by the matrix and polytetrafluoroethylene deposits.
Abstract The interest in nanomaterials for papermaking industry has strongly increased in the lat... more Abstract The interest in nanomaterials for papermaking industry has strongly increased in the latest decade in order to improve the properties of existing paper products or create new functionalities to papers. In this chapter, a broad overview of nanomaterials derived from paper products or nanofillers used during papermaking is given. The recent advances in producing nanocellulose as microfibrillated cellulose or cellulose nanowhiskers are discussed, together with the preparation routes for a range of inorganic and organic nanofillers. The electrospinning of paper constituents is an alternative way for the creation of nanostructured materials. Some novel trends include the in situ modification of nanofibers and nanofillers in order to tune their surface properties. However, most prominent challenges remain associated with the definition of suitable processing conditions, which are evaluated in terms of rheology and retention properties of nanomaterials. The benefits of nanofillers and nanopigments to create several functionalities to the paper bulk or surface are shortly discussed.
Cellulose fibers are advantageous reinforcing materials for bio-based composites because of their... more Cellulose fibers are advantageous reinforcing materials for bio-based composites because of their availability and good mechanical properties. Several chemical processes have been developed to turn the native fibers into micro- (MFC) or nanofibrillated (NFC) cellulose fibers. These nanocomponents are believed to even have stronger reinforcing capacity because of surface interaction effects at the nanoscale and formation of a fine web structure. During further processing of fibrillated cellulose in combination with a biopolymer matrix, however, there is evidence of agglomeration due to the hydrophilic nature of the fibers and incompatibility with the polymer matrix. In our approach, surface modification of the micro- and nanofibrillated cellulose is done by the in-situ deposition of hydrophobic nanoparticles onto the fiber surface, allowing to tune the required hydrophobicity of the cellulose additives and to make them compatible with extrusion applications, as demonstrated for PLA biopolymers.
The coefficients of friction and wear rates of thermoset polyester matrix composites with plain w... more The coefficients of friction and wear rates of thermoset polyester matrix composites with plain woven polyester fabric reinforcement were studied during reciprocating sliding under adhesive line contact at 50 to 200 N normal loads and 0.3 to 1.2 m/s sliding velocities. The samples were prepared along different orientations of the fabric relatively to the sliding surface and sliding directions, including 0°, 30°, 45°, 60° and 90° in-plane directions and thickness z direction. The coefficients of friction and wear rates were maximum along 90° and minimum along 45° for pure and polytetrafluoroethylene-filled composites. For the latter, overload conditions were minimized, and friction and wear became low for perpendicular fabric orientations. Although sliding is controlled by solid lubrication of polytetrafluoroethylene, the fiber orientations remain dominating the friction under mild sliding conditions. The differences between friction properties along weft and warp orientations could be correlated with mechanical properties along those directions. However, a systematic study in parallel with interpretation of the thermal heating could provide better insights in dry sliding properties. By considering the effects of thermal heating, thermo-mechanical sliding conditions in the interface controlled self-lubricating properties of polytetrafluoroethylene. The wear mechanisms along 0° and 90° directions were mainly determined by the fabric reinforcement, and the sliding along off-axis 45° and thickness directions was mainly controlled by the matrix and polytetrafluoroethylene deposits.
Abstract The interest in nanomaterials for papermaking industry has strongly increased in the lat... more Abstract The interest in nanomaterials for papermaking industry has strongly increased in the latest decade in order to improve the properties of existing paper products or create new functionalities to papers. In this chapter, a broad overview of nanomaterials derived from paper products or nanofillers used during papermaking is given. The recent advances in producing nanocellulose as microfibrillated cellulose or cellulose nanowhiskers are discussed, together with the preparation routes for a range of inorganic and organic nanofillers. The electrospinning of paper constituents is an alternative way for the creation of nanostructured materials. Some novel trends include the in situ modification of nanofibers and nanofillers in order to tune their surface properties. However, most prominent challenges remain associated with the definition of suitable processing conditions, which are evaluated in terms of rheology and retention properties of nanomaterials. The benefits of nanofillers and nanopigments to create several functionalities to the paper bulk or surface are shortly discussed.
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Papers by Pieter Samyn