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    EFFECT OF ACCELERATED AGEING ON SOME SURFACE PROPERTIES OF UV-COATED HACKBERRY (Celtis australis L.) WOOD PARQUET
    (Inst Technol Drewna, 2021) Ayata, Umit; Esteves, Bruno; Gurleyen, Levent; Cakicier, Nevzat; Ferreira, Jose; Domingos, Idalina; Turk, Mutlu
    The importance of UV-curable coatings is currently increasing. In the parquet industry, where UV systems are applied, it is beneficial to investigate new tree species as potential raw materials. This study was carried out to determine the effect of accelerated ageing on some surface properties of hackberry (Celtis australis L.) wood treated with UV system parquet varnish. UV system parquet varnishes were applied to hackberry wood surfaces in three and five layers, according to the requirements of industrial applications. The varnished surfaces were then exposed to UV rays for 252 and 504 h using UVA-340 lamps in a QUV ageing device. Glossiness, colour parameters, pendulum hardness and adhesion strength (pull-off) (MPa) were determined for the coated samples before and after ageing, and the results for the aged and unaged test samples were compared. Analysis of variance showed that the results were significant for all tests. The results for all tests varied by ageing time.
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    Effect of Heat Treatment on Shore-D Hardness of Some Wood Species
    (North Carolina State Univ Dept Wood & Paper Sci, 2021) Esteves, Bruno; Sahin, Sirri; Ayata, Umit; Domingos, Idalina; Ferreira, Jose; Gurleyen, Levent
    Hardness is an important wood property for several applications. Typically, it is necessary to use traditional methods, such as a universal test machine, to determine a wood's hardness value. This work reports the hardness of some wood species before and after heat treatment (ThermoWood method) using the Shore-D hardness method. The Shore-D hardness value of untreated wood ranged between 35.3 for Limba wood and 77.2 for Santos wood. With heat treatment, hardness decreased, and the decrease was greater for samples that underwent harsher treatment (2 h at 212 degrees C). The decrease of hardness was highest for Sipo wood (14%) and the lowest for Afrormosia wood (2.5%). Analysis of variance tests showed that there was a significant difference between wood species, heat treatment, and the interaction between both variables at the chosen level of significance (P <= 0.05). Results showed that Shore-D hardness could be used to measure hardness directly in a production line or in small wood companies without using a universal test machine.