scholarly journals Influence of the adhesive formulation on the mechanical properties and bonding performance of polyurethane prepolymers

Holzforschung ◽  
2011 ◽  
Vol 65 (6) ◽  
pp. 835-844 ◽  
Author(s):  
Sebastian Clauß ◽  
Joseph Gabriel ◽  
Alexander Karbach ◽  
Mathias Matner ◽  
Peter Niemz

Abstract Only small amounts of additives are needed to formulate one-component polyurethane (1C PUR) adhesives for various applications. The current study illuminates the effects of the formulation on the mechanical properties of pure adhesives, on the one hand, and their performance in bonded wood joints on the other. Tensile shear tests on bonded wood joints, tensile tests on adhesive films, and nanoindentation measurements in the interphase region of the bond were performed. Analyses by means of infrared, atomic force, and electron microscopy provided the explanatory basis for the results obtained. Additionally to laboratory made 1C PUR, unmodified commercial 1C PUR, melamine-urea-formaldehyde (MUF), and phenol-resorcinol-formaldehyde (PRF) were tested for comparison. The results obtained confirm that the mechanical properties of 1C PUR adhesives are significantly affected by their prepolymer composition. The adhesive formulation by means of additives, on the other hand, does not affect the mechanical properties but is to a large extent responsible for the bonding performance.

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1661
Author(s):  
Katarzyna Adamiak ◽  
Katarzyna Lewandowska ◽  
Alina Sionkowska

Collagen films are widely used as adhesives in medicine and cosmetology. However, its properties require modification. In this work, the influence of salicin on the properties of collagen solution and films was studied. Collagen was extracted from silver carp skin. The rheological properties of collagen solutions with and without salicin were characterized by steady shear tests. Thin collagen films were prepared by solvent evaporation. The structure of films was researched using infrared spectroscopy. The surface properties of films were investigated using Atomic Force Microscopy (AFM). Mechanical properties were measured as well. It was found that the addition of salicin modified the roughness of collagen films and their mechanical and rheological properties. The above-mentioned parameters are very important in potential applications of collagen films containing salicin.


1999 ◽  
Author(s):  
Takeru Ohki ◽  
Shinya Ikegaki ◽  
Ken Kurasiki ◽  
Hiroyuki Hamada ◽  
Masaharu Iwamoto

Abstract In this study, fracture behavior and strength in the flat braided bar with a circular hole were investigated by static and fatigue test. Two type of specimens were prepared. They are a braided flat bar with an integrally-formed braided hole and a braided flat bar with a machined hole. Moreover, we also examined a specimen that had a metal pin inserted at the circular hole. This specimen was subjected to a static tensile test. The results of the tensile tests indicate that the strength of the flat bar with a braided hole was larger than that of the one with the machined hole. Furthermore, from the results of the fatigue tests, the flat bar with the braided hole showed higher fatigue property than that of the one with the machined hole.


2000 ◽  
Vol 122 (4) ◽  
pp. 420-424 ◽  
Author(s):  
Takeru Ohki ◽  
Shinya Ikegaki ◽  
Ken Kurasiki ◽  
Hiroyuki Hamada ◽  
Masaharu Iwamoto

In this study, fracture behavior and strength in the flat braided bar with a circular hole were investigated by static and fatigue test. Two types of specimen were prepared. They are a braided flat bar with an integrally formed braided hole and a braided flat bar with a machined hole. Moreover, we also examined a specimen that had a metal pin inserted at the circular hole. This specimen was subjected to a static tensile test. The results of the tensile tests indicate that the strength of the flat bar with a braided hole was larger than that of the one with the machined hole. Furthermore, from the results of the fatigue tests, the flat bar with the braided hole showed higher fatigue property than that of the one with the machined hole. [S0094-4289(00)02604-9]


Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1069 ◽  
Author(s):  
Gabriele Nanni ◽  
José A. Heredia-Guerrero ◽  
Uttam C. Paul ◽  
Silvia Dante ◽  
Gianvito Caputo ◽  
...  

Poly(furfuryl alcohol) (PFA) is a bioresin synthesized from furfuryl alcohol (FA) that is derived from renewable saccharide-rich biomass. In this study, we compounded this bioresin with polycaprolactone (PCL) for the first time, introducing new functional polymer blends. Although PCL is biodegradable, its production relies on petroleum precursors such as cyclohexanone oils. With the method proposed herein, this dependence on petroleum-derived precursors/monomers is reduced by using PFA without significantly modifying some important properties of the PCL. Polymer blend films were produced by simple solvent casting. The blends were characterized in terms of surface topography by atomic force microscopy (AFM), chemical interactions between PCL and PFA by attenuated total reflection-Fourier transform infrared (ATR-FTIR), crystallinity by XRD, thermal properties by differential scanning calorimetry (DSC), and mechanical properties by tensile tests and biocompatibility by direct and indirect toxicity tests. PFA was found to improve the gas barrier properties of PCL without compromising its mechanical properties, and it demonstrated sustained antioxidant effect with excellent biocompatibility. Our results indicate that these new blends can be potentially used in diverse applications ranging from food packing to biomedical devices.


Author(s):  
Samuel Oluyinka Olaniran ◽  
Gaspard Clerc ◽  
Etienne Cabane ◽  
Andreas J. Brunner ◽  
Markus Rüggeberg

Abstract Rubberwood is widely planted for latex production. At the cessation of latex yield it becomes a viable timber source in the wood industry. While good bonding performance of rubberwood has been reported, quantitative information to support this statement is missing. In this study, the tensile shear strength (TSS) and wood failure percentage (WFP) of unmodified and acetylated rubberwood in both wet and dry conditions were examined. Three frequently used adhesives were selected: one-component polyurethane (1C PUR), melamine-urea-formaldehyde (MUF), and phenol-resorcinol-formaldehyde (PRF). Furthermore, fatigue behaviour was analysed for PRF-bonded samples by cyclic loading. Results showed that in dry state, the TSS and WFP of acetylated rubberwood is comparable to the unmodified samples for all adhesives. In wet condition, the performance of bonded rubberwood was improved by acetylation. Cyclic loading revealed comparable fatigue behaviour of bonded unmodified and acetylated rubberwood. This investigation provides first quantitative information on the performance of bonded rubberwood, which can be a valuable input for the production of laminated timber products for structural purposes.


2008 ◽  
Vol 591-593 ◽  
pp. 252-257 ◽  
Author(s):  
Bernardo N. Nobrega ◽  
Tiago Eberle ◽  
Waldyr Ristow

A PADS (Plasma Assisted Debinding and Sintering) reactor developed by Lupatech S.A. has been employed to MIM process two Ni-based superalloys under Argon, at temperatures in the 1280 -1310 °C range, and for 2 to 3 hours. Both materials have chemical compositions similar to that of standard Nimonic® 90 but differ considerably in their powder characteristics. One type of powder was gas-atomized whereas the other was water-atomized. Samples of both materials in as-sintered states as well as subject to different HIP and heat treating conditions have been characterized mechanically in tensile tests and by HV measurements. The best overall results are attained by the water-atomized material sintered at lower temperatures. The PADS processing of these superalloys shows marked advantages over more conventional PM processing technologies. These results are particularly relevant to the development of turbine components for the automotive and aerospace industries.


1973 ◽  
Vol 8 (4) ◽  
pp. 267-276 ◽  
Author(s):  
P S Theocaris

The internal structure of the stress-optical coefficients, as they are related to various direct interferometric methods, has been analysed and the nature of their components studied. It is shown that the stress-optical coefficients are composed of two parts. The one part depends on the variation of the mechanical properties; the other is related to the variation of the refractive index of the polymer. The influence of the mechanical properties is considerable and comparable to the influence of the optical properties. The study of the mechanical and optical contributions to the values of the stress-optical coefficients included not only the linear, but also the non-linear viscoelastic behaviour of the polymers. It is concluded that the corresponding limits of linearity of these coefficients do not coincide. Furthermore, the influence of the mechanical properties on the stress-optical coefficients is increasing relatively to the influence of the optical properties in the non-linear region.


Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5862
Author(s):  
Ingo Ortlepp ◽  
Jaqueline Stauffenberg ◽  
Eberhard Manske

This paper deals with a planar nanopositioning and -measuring machine, the so-called nanofabrication machine (NFM-100), in combination with a mounted atomic force microscope (AFM). This planar machine has a circular moving range of 100 mm. Due to the possibility of detecting structures in the nanometre range with an atomic force microscope and the large range of motion of the NFM-100, structures can be analysed with high resolution and precision over large areas by combining the two systems, which was not possible before. On the basis of a grating sample, line scans over lengths in the millimetre range are demonstrated on the one hand; on the other hand, the accuracy as well as various evaluation methods are discussed and analysed.


Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2650
Author(s):  
Thibault Lemaire ◽  
Erica Gea Rodi ◽  
Valérie Langlois ◽  
Estelle Renard ◽  
Vittorio Sansalone

In recent years the interest in the realization of green wood plastic composites (GWPC) materials has increased due to the necessity of reducing the proliferation of synthetic plastics. In this work, we study a specific class of GWPCs from its synthesis to the characterization of its mechanical properties. These properties are related to the underlying microstructure using both experimental and modeling approaches. Different contents of Miscanthus giganteus fibers, at 5, 10, 20, 30 weight percent’s, were thus combined to a microbial matrix, namely poly (3-hydroxybutyrate)-co-poly(3-hydroxyvalerate) (PHBHV). The samples were manufactured by extrusion and injection molding processing. The obtained samples were then characterized by cyclic-tensile tests, pycnometer testing, differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and microscopy. The possible effect of the fabrication process on the fibers size is also checked. In parallel, the measured properties of the biocomposite were also estimated using a Mori–Tanaka approach to derive the effective behavior of the composite. As expected, the addition of reinforcement to the polymer matrix results in composites with higher Young moduli on the one hand, and lower failure strains and tensile strengths on the other hand (tensile modulus was increased by 100% and tensile strength decreased by 23% when reinforced with 30 wt % of Miscanthus fibers).


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 662
Author(s):  
L.A. Can-Herrera ◽  
A.I. Oliva ◽  
M.A.A. Dzul-Cervantes ◽  
O.F. Pacheco-Salazar ◽  
J.M. Cervantes-Uc

The aim of this work is to investigate the effect of the applied voltage on the morphological and mechanical properties of electrospun polycaprolactone (PCL) scaffolds for potential use in tissue engineering. The morphology of the scaffolds was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and the BET techniques for measuring the surface area and pore volume. Stress-strain curves from tensile tests were obtained for estimating the mechanical properties. Additional studies for detecting changes in the chemical structure of the electrospun PCL scaffolds by Fourier transform infrared were performed, while contact angle and X-ray diffraction analysis were realized for determining the wettability and crystallinity, respectively. The SEM, AFM and BET results demonstrate that the electrospun PCL fibers exhibit morphological changes with the applied voltage. By increasing the applied voltage (10 to 25 kV) a significate influence was observed on the fiber diameter, surface roughness, and pore volume. In addition, tensile strength, elongation, and elastic modulus increase with the applied voltage, the crystalline structure of the fibers remains constant, and the surface area and wetting of the scaffolds diminish. The morphological and mechanical properties show a clear correlation with the applied voltage and can be of great relevance for tissue engineering.


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