Eser SÖZEN

Hızlandırılmış UV Yaşlandırma ile Odunda Meydana Gelen Renk, FTIR ve Mikroskobik Değişimlerin Belirlenmesi

Yağmur, güneş, rüzgâr gibi doğal şartlar ahşap malzemenin fiziksel, kimyasal ve mekanik özelliklerinde değişimlere neden olmaktadır. Bu değişimler çoğunlukla olumsuz olarak nitelendirilmektedir. Ancak, bazı durumlarda bu olumsuz değişimler doğallığı ifade etmesi veya bir sonraki işlem için gerekli olmasında dolayı tercih edilebilmektedir. Bazı mobilya ve iç mekan tasarımlarında eskitme olarak nitelendirilen ahşaplar özellikle tercih edilmektedir. Bu çalışmada, kayın (Fagus orientalis L.) odununda hızlandırılmış UV yaşlandırma testi sonrasında renk değişimi, lignin oranı ve hücre çeperinde meydana gelen değişimler incelenmiştir. Renk ölçümü, ISO 7724 (1984) standartlarına uygun olarak UV yaşlandırma testi öncesinde ve sonrasında yapılmıştır. FTIR analizi sonucunda 945-1132 absorbans değerleri arasındaki hemiselüloz ve lignin oranında kontrol örneklerine göre %14,78 azalma meydana geldiği görülmüştür. Hücre çeperinde meydana gelen değişimler SEM analizleri ile enine kesit ve teğette ayrı ayrı incelenmiştir. Enine kesitte UV sonrası kontrol örneklerine göre belirgin çatlakların oluştuğu görülmüştür. Boyuna yönde ise paranşim hücrelerinde dağılmaların olduğu saptanmıştır.

Anahtar Kelimeler:

Hızlandırılmış UV yaşlandırma, FTIR, lignin, SEM, hücre çeperi

Determination of Color, FTIR and Microscopic Changes in Wood by Accelerated UV Aging

Natural conditions such as rain, sun, wind cause changes in the physical, chemical and mechanical properties of the wood material. These changes are often described as negative. However, in some cases, these negative changes may be preferred because they express naturalness or are necessary for the next process. In some furniture and interior designs, woods described as aging are especially preferred. In this study, color change, lignin ratio and changes in cell wall after accelerated UV aging test in beech (Fagus orientalis L.) wood were investigated. Color measurement was done before and after UV aging test in accordance with ISO 7724 (1984) standards. As a result of FTIR analysis, it was seen that there was a decrease of 14.78% in the ratio of hemicellulose and lignin between the absorbance values of 945-1132 compared to the control samples. Changes in the cell wall were examined separately in cross section and tangent by SEM analysis. Significant cracks were observed in the cross section compared to the post-UV control samples. In the longitudinal direction, it was determined that there are dispersions in the parenchyma cells.

Keywords:

Accelerated UV aging, FTIR, lignin, SEM, cell wall,

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