TY - JOUR
T1 - Tuning Thermal, Morphological, and Physicochemical Properties of Thermoplastic Polyurethanes (TPUs) by the 1,4-Butanediol (BDO)/Dipropylene Glycol (DPG) Ratio
AU - Ernzen, Juliano R
AU - Romoaldo, Carlos H
AU - Gommes, Cedric
AU - Covas, José A
AU - Marcos-Fernández, Angel
AU - Fiorio, Rudinei
AU - Bianchi, Otávio
N1 - Funding Information:
The authors thank the Brazilian agency Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for their financial support. OB thanks the National Council for Scientific and Technological Development (CNPq) fellows (grant number 308567/2018-8 and 305814/2021-4). AMF thanks the Spanish Ministerio de Economía e Innovación (project PID2020-119047RB-I00) for partial financial support. The authors also acknowledge the Brazilian Synchrotron Light Laboratory (LNLS) for the use of its facilities (SAXS1 beamline).
Funding Information:
This research was funded by Brazilian National Council for Scientific and Technological Development (CNPq) grant numbers 308567/2018-8 and 305814/2021-4. Spanish Ministerio de Economía e Innovación grant numbers PID2020-119047RB-I00 funded the APC.
Publisher Copyright:
© 2022 by the authors.
PY - 2022/8/3
Y1 - 2022/8/3
N2 - Thermoplastic polyurethanes (TPUs) are versatile polymers presenting a broad range of properties as a result of their countless combination of raw materials-in essence, isocyanates, polyols, and chain extenders. This study highlights the effect of two different chain extenders and their combination on the structure-property relationships of TPUs synthesized by reactive extrusion. The TPUs were obtained from 4,4-diphenylmethane diisocyanate (MDI), polyester diols, and the chain extenders 1,4-butanediol (BDO) and dipropylene glycol (DPG). The BDO/DPG ratios studied were 100/0, 75/25, 50/50, 25/75, and 0/100 wt.%. The TPUs were characterized by size exclusion chromatography (SEC), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), UV-vis spectroscopy, and physical-mechanical properties. The results indicate that DPG promotes compatibility between rigid (HS) and flexible (SS) segments of TPUs. Consequently, increasing DPG content (>75 wt.%) reduced the organization of the rigid segments and the degree of phase separation, increasing the polydispersity of the interdomain distance and the transparency in the UV-visible spectrum of the TPUs. Furthermore, increasing DPG content also reduced the amount of hydrogen bonds present in the rigid phase, reducing or extinguishing its glass transition temperature (TgHS) and melting temperature (Tm), and increasing the glass transition temperature of the flexible phase (TgSS). Therefore, increasing DPG content leads to a deterioration in mechanical properties and hydrolysis resistance.
AB - Thermoplastic polyurethanes (TPUs) are versatile polymers presenting a broad range of properties as a result of their countless combination of raw materials-in essence, isocyanates, polyols, and chain extenders. This study highlights the effect of two different chain extenders and their combination on the structure-property relationships of TPUs synthesized by reactive extrusion. The TPUs were obtained from 4,4-diphenylmethane diisocyanate (MDI), polyester diols, and the chain extenders 1,4-butanediol (BDO) and dipropylene glycol (DPG). The BDO/DPG ratios studied were 100/0, 75/25, 50/50, 25/75, and 0/100 wt.%. The TPUs were characterized by size exclusion chromatography (SEC), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), UV-vis spectroscopy, and physical-mechanical properties. The results indicate that DPG promotes compatibility between rigid (HS) and flexible (SS) segments of TPUs. Consequently, increasing DPG content (>75 wt.%) reduced the organization of the rigid segments and the degree of phase separation, increasing the polydispersity of the interdomain distance and the transparency in the UV-visible spectrum of the TPUs. Furthermore, increasing DPG content also reduced the amount of hydrogen bonds present in the rigid phase, reducing or extinguishing its glass transition temperature (TgHS) and melting temperature (Tm), and increasing the glass transition temperature of the flexible phase (TgSS). Therefore, increasing DPG content leads to a deterioration in mechanical properties and hydrolysis resistance.
KW - COATINGS
KW - DSC
KW - MICROPHASE SEPARATION
KW - PARAMETERS
KW - POLYMER BLENDS
KW - SEGMENTED POLYURETHANES
KW - TRANSPARENT
KW - chain extender
KW - polyurethane thermoplastics
KW - reactive extrusion
KW - transparency
U2 - 10.3390/polym14153164
DO - 10.3390/polym14153164
M3 - Article
C2 - 35956679
SN - 2073-4360
VL - 14
JO - Polymers
JF - Polymers
IS - 15
M1 - 3164
ER -