Effect of tincal and borax pentahydrate additives on the physical and mechanical properties of PU foams

Abstract

Polyurethane foams are widely used in the construction, automotive, home appliance, and furniture industries due to their superior properties, such as thermal, acoustic, and moisture insulation. Due to their lightweight structure, high energy absorption capacity, and low thermal conductivity, they are particularly preferred in sandwich panel systems. However, improving the physical, thermal, and mechanical properties of these materials is important for enhancing their performance. In this study, the effects of adding tincal and borax pentahydrate in varying proportions to a polyurethane matrix were investigated with the aim of improving the physical, thermal, and mechanical properties of polyurethane foams used as core materials in sandwich panels. Tincal and borax pentahydrate were separately added to polyurethane foam samples at concentrations of 1%, 2%, and 3% by weight, and the density, thermal conductivity, compressive strength, and tensile strength properties of the resulting samples were examined. In addition, the effects of additive type and ratio on the foam structure were investigated by analysing the stress-strain curves and SEM images of selected samples. According to the findings, the addition of tincal significantly reduced the density of the polyurethane foams compared to the reference sample, while the addition of borax pentahydrate maintained the density at levels closer to the reference value. In terms of thermal conductivity, the lowest value among the tincal-added samples was obtained in the sample containing 1% tincal, whereas the lowest value in the borax pentahydrate-added group was measured in the sample containing 2% borax pentahydrate. While the reference sample exhibited the highest compressive strength, among the boron-containing samples, the foams containing 2% tincal and 1% borax pentahydrate demonstrated higher performance. In terms of tensile strength, the highest result was obtained in polyurethane foams containing 2% tincal, showing a 19% increase compared to the reference value. Furthermore, it was determined that foams containing 1% borax pentahydrate provided 13.7% higher tensile strength compared to the reference sample. SEM images showed that cell size, cell distribution, and cell wall integrity changed depending on the type of boron dopant. It was concluded that, in improving the performance of polyurethane foams, the type of boron compound is as important as the additive ratio; in particular, a 2% addition of tincal stood out in terms of tensile performance, while certain boron additive ratios also contributed positively to thermal insulation performance.

Keywords

• Borax pentahydrate
• Cellular structure
• Mechanical properties
• Polyurethane foam
• Sandwich panel
• Tincal

Tinkal ve boraks pentahidrat katkılarının PU köpüklerin fiziksel ve mekanik özellikleri üzerindeki etkisi

Abstract

Özet Poliüretan köpükler; ısı, ses ve nem yalıtımı gibi üstün özellikleri sayesinde inşaat, otomotiv, beyaz eşya ve mobilya sektörlerinde yaygın olarak kullanılmaktadır. Hafif yapısı, yüksek enerji emme kapasitesi ve düşük ısı iletkenliği nedeniyle sandviç panel sistemlerinde tercih edilmektedir. Ancak, bu malzemelerin mekanik dayanım ve çevresel sürdürülebilirlik açısından geliştirilmesi gerekmektedir. Bor mineralleri, yüksek ısıl kararlılık, alev geciktiricilik ve kimyasal direnç kazandırma özellikleriyle polimer matrislerin performansını artıran çevre dostu katkı maddeleri olarak öne çıkmaktadır. Bu çalışmada, sandviç panellerin çekirdek malzemesi olarak kullanılan poliüretan köpüklerin mekanik ve fiziksel özelliklerinin geliştirilmesi amacıyla, farklı oranlarda bor minerali katkılarının etkisi incelenmiştir. Bu kapsamda, poliüretan matrisine ağırlıkça %1, %2 ve %3 oranlarında tinkal ve boraks pentahidrat ilave edilmiştir. Elde edilen numuneler üzerinde yapılan deneysel çalışmalar sonucunda, %2 tinkal katkısının poliüretan köpüğün çekme dayanımını yaklaşık %20 oranında artırdığı, buna karşılık yoğunluğunu %24 oranında azalttığı belirlenmiştir. Diğer yandan, poliüretan içerisine %1 boraks pentahidrat ilavesinin çekme dayanımında %14 artışa, yoğunlukta ise %5 azalmaya neden olduğu tespit edilmiştir. Sonuçlar, bor türevlerinin poliüretan yapısına entegrasyonunun köpük malzemenin hafifliğini korurken mekanik dayanımını iyileştirebileceğini göstermektedir. Bu bulgular, bor mineralleriyle modifiye edilmiş poliüretan köpüklerin, yüksek performanslı ve sürdürülebilir kompozit panel uygulamaları için potansiyel taşıdığını ortaya koymaktadır.

Keywords

• Boraks pentahidrat
• Hücresel yapı
• Mekanik özellikler
• Poliüretan köpük
• Sandviç panel
• Tinkal

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