Investigation of Effects of a Polymeric Chain Extender on the Properties of Recycled Poly (Butylene Terephthalate)

Abstract

Poly (butylene terephthalate) (PBT) is one of the most used polyesters today; however, the attempts to convert PBT wastes into value-added products are still limited in the recycling context. One of the major drawbacks of the PBT recycling is thermal degradation during multiple melt processing cycles that leads to deterioration in molecular weight and properties of the polymer. In this study, recycled PBT (rPBT) was compounded with a polymeric chain extender (Joncryl ADR 4368) at different loadings (0.5, 1, 1.5 wt%) in a twin-screw extruder. The rheological, mechanical, and thermal properties of the samples were investigated using different characterization techniques. The rheological results showed that addition of chain extender improved the viscoelastic properties of rPBT due to recoupling of the broken chains. The profound effect of chain extender on upgrading properties of rPBT was also confirmed by tensile test results. The samples containing chain extender showed enhancement in elastic modulus and tensile strength, whereas the strain at break values decreased due to chain branching. The samples containing chain extender showed enhancement in elastic modulus and tensile strength, whereas the strain at break values decreased due to chain branching. The effect of chain extender on branched structure of the samples was also observed from the lower crystallinity values. Thermogravimetric analysis indicated that the chain extender increased thermal decomposition temperature of the PBT. The improvement in the properties of the samples containing chain extender became more significant with increase in chain extender concentration.

Keywords

• Poly(butylene terephthalate)
• Recycling
• Thermal Degradation
• Chain Extender
• Extruder

Polimerik Bir Zincir Uzatıcının Geri Dönüştürülmüş Poli(Bütilen Tereftalat)’ın Özelliklerine Etkilerinin İncelenmesi

Abstract

Poli(bütilen tereftalat) (PBT) günümüzde en fazla kullanılan poliesterlerdendir, ancak PBT atıkların geri dönüşüm kapsamında katma değerli ürünlere dönüşmesine yönelik girişimler hala sınırlıdır. PBT geri dönüşümünün en önemli zorluklarından birisi çoklu eriyik işleme döngüleri sırasındaki termal bozunma olup, polimerin molekül ağırlığı ve özelliklerinde kayıplara yol açmaktadır. Bu çalışmada geri dönüştürülmüş PBT (Gd. PBT) farklı yükleme oranındaki (%ağ. 0.5, 1, 1.5) polimerik bir zincir uzatıcı (Joncryl ADR 4368) ile çift vidalı ekstrüderde harmanlanmıştır. Örneklerin reolojik, mekanik ve termal özellikleri farklı karakterizasyon yöntemleri ile incelenmiştir. Reolojik sonuçlar zincir uzatıcının eklenmesiyle kopan zincirlerin tekrar bağlanarak Gd. PBT’nin viskoelastik özelliklerinin geliştiğini göstermiştir. Zincir uzatıcının Gd. PBT’nin özelliklerine olan önemli etkisi çekme testi sonuçlarından da doğrulanmıştır. Zincir uzatıcı içeren örneklerin elastik modül ve çekme dayanımları artış gösterirken, kopmadaki uzama değerleri zincir dallanmasına bağlı olarak düşmüştür. Zincir uzatıcının örneklerin dallanmış yapısına etkisi düşük kristalinite değerlerinden de gözlemlenmiştir. Termogravimetrik analiz zincir uzatıcının Gd. PBT’nin termal bozunma sıcaklığını arttırdığını göstermiştir. Zincir uzatıcı içeren örneklerin özelliklerindeki iyileşme artan zincir uzatıcı konsantrasyonu ile daha belirgin olmuştur.

Keywords

• Poli(bütilen tereftalat)
• Geri Dönüşüm
• Termal Bozunma
• Zincir Uzatıcı
• Ekstrüder

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