Effects of Annealing on the Thermomechanical Properties and Crystallization Behavior of FDM-Printed High-Temperature PLA and Glass Fiber PLA Composites
Polymer Engineering and Science, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1002/pen.70848
- Dergi Adı: Polymer Engineering and Science
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Applied Science & Technology Source, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Engineering Source (EBSCO), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Anahtar Kelimeler: additive manufacturing, crystallization, glass fiber reinforcement, HT-PLA, thermal annealing, thermomechanical characterization
- Manisa Celal Bayar Üniversitesi Adresli: Evet
Özet
Polylactic acid (PLA) combines renewable sourcing and reliable printability with limited stiffness retention near its glass-transition region. This study examines how annealing at 90°C, 110°C, 130°C, and 150°C for 30 min affects FDM-printed high-temperature PLA (HT-PLA) and 12 wt% glass-fiber-reinforced HT-PLA (HT-PLA-GF). Differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, orientation-dependent mechanical tests, tensile-fracture SEM, and three-point-bending dynamic mechanical analysis were evaluated together. DSC calculations showed that the homocrystalline contribution of neat HT-PLA increased from 26.14% as printed to 50.33% at 110°C, whereas HT-PLA-GF approached a plateau near 38% between 110°C and 150°C. At 150°C, longitudinal tensile strength decreased by 25.1% for HT-PLA and 40.4% for HT-PLA-GF, while transverse flexural strength decreased by 37.0% and 49.5%, respectively. SEM revealed layer-related discontinuities in transverse neat HT-PLA and a mixed composite failure morphology involving fiber pull-out, fiber fracture, sockets, and matrix tearing. Annealing nevertheless improved elevated-temperature stiffness retention. The DMA-derived apparent HDT-1.80 MPa increased from 65.7°C to 85.7°C for neat HT-PLA and from 66.9°C to 114.6°C for HT-PLA-GF. The results demonstrate that improved thermal stiffness does not imply improved failure strength. Within the investigated conditions, 90°C provided the most balanced response, whereas 150°C maximized apparent heat-deflection resistance at the cost of substantial tensile and flexural penalties.