Upcycling Recycled PET into High-Performance Polyurethane Coating and Engineering Materials: Effect of NCO Index on Mechanical, Stability, and Surface Properties
Abstract
Upcycling of polyethylene terephthalate (PET) waste into high-value polymeric materials offers a promising pathway toward circular and sustainable polymer engineering. In this work, polyurethane (PU) films were synthesized from recycled PET (rPET)-based polyols, and the influence of the isocyanate index (NCO index: 100-200) on the network structure and functional properties of the resulting materials was investigated. FT-IR results supported the formation of urethane linkages between the rPET-based polyol and polymeric methylene diphenyl diisocyanate (PMDI), indicating successful network formation. Increasing the NCO index significantly enhanced cross-link density, reflected by an increase in gel content from 54.97 to 93.46% and a decrease in swelling ratio from 254.58% to 133.30%. This structural evolution led to improved mechanical performance, with tensile strength and Young's modulus reaching 7.26 and 5.29 N/mm 2 , respectively. Thermal analysis further revealed an increase in glass transition temperature (-32.05-0.93 °C) and enhanced thermal stability with higher char yields (17.57-24.71%). Surface analyses demonstrated smoother, denser, and more hydrophobic morphologies at elevated NCO indices. An optimal balance of mechanical, thermal, and surface properties was achieved at NCO indices of 150-175, highlighting the potential of rPET-based PU films as sustainable coating and engineering materials for advanced applications.
Related
- Effects of Mepiquat Chloride Application Timing and Concentration on Soybean Plant Architecture and Stem Mechanical Properties
- Associations of age, sex, and bicuspid aortic valve with biaxial mechanical properties and circumferential residual stress in ascending thoracic aortic aneurysm
- Variation and adaptation in the mechanical properties of primate molar tooth enamel
- Microstructure determines the difference between the mechanical properties of melanized and non‐melanized domestic pigeon feathers
- Mechanical-acoustic-optical response properties in uniaxial compression failure of rock masses with different dissolution degrees
BibTeX
@article{thusanaphoom2026upcycling,
title = {{Upcycling Recycled PET into High-Performance Polyurethane Coating and Engineering Materials: Effect of NCO Index on Mechanical, Stability, and Surface Properties}},
author = {Panachai Thusanaphoom and Jureeporn Yuennan and Wichain Chailad and Sineenard Songsri and Vanchai Laemlaksakul and Jennifer Rodon-Fores and Yutthana Wongnongwa and Nathapong Sukhawipat},
journal = {ACS Polymers Au},
year = {2026},
month = aug,
doi = {10.1021/acspolymersau.6c00147},
url = {https://hal.science/hal-05772449v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Upcycling Recycled PET into High-Performance Polyurethane Coating and Engineering Materials: Effect of NCO Index on Mechanical, Stability, and Surface Properties
AU - Panachai Thusanaphoom
AU - Jureeporn Yuennan
AU - Wichain Chailad
AU - Sineenard Songsri
AU - Vanchai Laemlaksakul
AU - Jennifer Rodon-Fores
AU - Yutthana Wongnongwa
AU - Nathapong Sukhawipat
PY - 2026
DA - 2026/08/06
JO - ACS Polymers Au
DO - 10.1021/acspolymersau.6c00147
UR - https://hal.science/hal-05772449v1
AB - Upcycling of polyethylene terephthalate (PET) waste into high-value polymeric materials offers a promising pathway toward circular and sustainable polymer engineering. In this work, polyurethane (PU) films were synthesized from recycled PET (rPET)-based polyols, and the influence of the isocyanate index (NCO index: 100-200) on the network structure and functional properties of the resulting materials was investigated. FT-IR results supported the formation of urethane linkages between the rPET-based polyol and polymeric methylene diphenyl diisocyanate (PMDI), indicating successful network formation. Increasing the NCO index significantly enhanced cross-link density, reflected by an increase in gel content from 54.97 to 93.46% and a decrease in swelling ratio from 254.58% to 133.30%. This structural evolution led to improved mechanical performance, with tensile strength and Young's modulus reaching 7.26 and 5.29 N/mm 2 , respectively. Thermal analysis further revealed an increase in glass transition temperature (-32.05-0.93 °C) and enhanced thermal stability with higher char yields (17.57-24.71%). Surface analyses demonstrated smoother, denser, and more hydrophobic morphologies at elevated NCO indices. An optimal balance of mechanical, thermal, and surface properties was achieved at NCO indices of 150-175, highlighting the potential of rPET-based PU films as sustainable coating and engineering materials for advanced applications.
SN - 2694-2453
ER -