Chemically-Modified Recycled PET/PBT Blends and Their Radio Frequency Welded Bead Foam Structures
Macromolecular Materials and Engineering, cilt.311, sa.7, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 311 Sayı: 7
- Basım Tarihi: 2026
- Doi Numarası: 10.1002/mame.70277
- Dergi Adı: Macromolecular Materials and Engineering
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Directory of Open Access Journals, Academic Search Ultimate (EBSCO), Natural Science Collection (ProQuest), Biological Science Database (ProQuest), Engineering Source (EBSCO), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Anahtar Kelimeler: bead foam welding, bead foaming, Joncryl chain extender, polybutylene terephthalate, recycled polyethylene terephthalate
- Yıldız Teknik Üniversitesi Adresli: Evet
Özet
This study investigates the rheological, thermal, bead foaming, and welded bead foam behaviors of recycled polyethylene terephthalate (rPET)/polybutylene terephthalate (PBT) blends modified with a multifunctional epoxy-based Joncryl chain extender. Three blend weight ratios (75/25, 50/50, and 25/75) were evaluated with and without 1.0 wt.% Joncryl. Bead foams were produced using CO2 physical blowing agent through continuous extrusion bead foaming. Melt rheological analysis revealed that PBT addition and Joncryl modification increase the complex viscosity and storage modulus of the blends. Differential scanning calorimetry (DSC) and hyper-DSC analyses confirmed that while co-crystallization occurs at slow cooling rates, fast cooling of 300°C/min induces crystalline phase immiscibility. This results in clear double-crystal melting peak formation in all blends and particularly in 50/50 blends. During the radio-frequency welding, the low- and high-melting-peak crystals facilitate strong bead-to-bead welding and maintain the overall foam structure, respectively. Flexural, tensile, and compressive mechanical analyses demonstrated the presence of stronger inter-bead welding of the modified 50/50 blends. At this blend ratio, specifically toughness, tensile strength, and strain at break were notably enhanced. Fracture surface analysis of welded bead foams confirmed intra-bead fracture resulting from high inter-bead weld strength in all blends.