Bülent AYDEMİR, Şenol ŞAHİN, Tülin ŞAHİN

Effect of Particle Size of Calcium Carbonate on the Short-Term Tensile Creep Properties of Polypropylene Block Copolymer (PPB)

Polypropylene block copolymer (PPB) composite materials consist of polypropylene and micro particle mineral filled materials that is calcium carbonate (CC). The samples to be used in the tests were formed by adding calcium carbonate (CC) mineral in three different particle sizes. The different commercial CC minerals average particle sizes are 1.65 μm, 2.15 μm, 5 μm. The PPB composite materials are prepared at constant quantities of CC with content of 17.5 percentage of the volume ratio (or 38.89% in weight). In this study, the short time tensile creep behavior of 17,5 vol. % different particle sizes CC filled PPB materials were investigated for different stress levels. Stress levels were selected from the stress below its yield strength. The stress levels are at 8 MPa, 16 MPa. As a result, it was found that the creep elongation or strain drop (∆ε) values decrease in the CC filled PPB materials according to the unfilled PPB material. In addition, it has been found that the absorbed energy levels reduce as the particle size increases.

Anahtar Kelimeler:

Creep, PPB, Particle size, Calcium carbonate

Polipropilen Kopolimerinde (PPB) Kalsiyum Karbonat Tane Boyutunun Kısa Süreli Çekme Sürünme Özellikleri Üzerine Etkisi

Polipropilen blok kopolimer (PPB) kompozit malzemeler, polipropilen ve mikro tane boyutlu mineral dolgulu malzemelerinden, yani kalsiyum karbonattan (CC) oluşur. Testlerde kullanılacak numuneler, üç farklı tane boyutunda kalsiyum karbonat (CC) mineralinin eklenmesiyle oluşturulmuştur. Farklı ticari CC minerallerinin ortalama tane boyutları 1.65 um, 2.15 um, 5 um'dir. PPB kompozit malzemeler, hacim oranının % 17.5'i (veya ağırlıkça % 38.89) içeriğinde sabit miktarda CC ile hazırlandı. Bu çalışmada, hacimce %17,5 olan ve farklı boyutlarda CC katkılı PPB kompozit malzemelerin kısa süreli çekme tip sürünme özellikleri farklı gerilme seviyeleri için incelenmiştir. Gerilme seviyeleri, akma dayanımının altındaki gerilmelerden seçilmiştir. Gerilme seviyeleri 8 MPa ve 16 MPa'dır. Sonuç olarak, katkısız PPB malzemeye göre CC katkılı PPB malzemelerde, sürünme uzaması veya uzama düşüşü (∆ε) değerleri azaldığı tespit edilmiştir. Ayrıca, tane büyüklüğü arttıkça depolanan enerji seviyelerinin azaldığı da bulunmuştur.

Keywords:

Sürünme, Polipropilen blok kopolimer (PPB), Tane boyutu, Kalsiyum karbonat (CC),

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