TY  - JOUR
U1  - Zeitschriftenartikel, wissenschaftlich - begutachtet (reviewed)
A1  - Riehle, Natascha
A1  - Athanasopulu, Kiriaki
A1  - Kutuzova, Larysa
A1  - Götz, Tobias
A1  - Kandelbauer, Andreas
A1  - Tovar, Günter
A1  - Lorenz, Günter
T1  - Influence of hard segment content and diisocyanate structure on the transparency and mechanical properties of poly(dimethylsiloxane)-based urea elastomers for biomedical applications
JF  - Polymers
N2  - The effect of hard segment content and diisocyanate structure on the transparency and mechanical properties of soft poly(dimethylsiloxane) (PDMS)-based urea elastomers (PSUs) was investigated. A series of PSU elastomers were synthesized from an aminopropyl-terminated PDMS (M¯n: 16,300 g·mol−1), which was prepared by ring chain equilibration of the monomers octamethylcyclotetrasiloxane (D4) and 1,3-bis(3-aminopropyl)-tetramethyldisiloxane (APTMDS). The hard segments (HSs) comprised diisocyanates of different symmetry, i.e., 4,4′-methylenebis(cyclohexyl isocyanate) (H12MDI), 4,4′-methylenebis(phenyl isocyanate) (MDI), isophorone diisocyanate (IPDI), and trans-1,4-cyclohexane diisocyanate (CHDI). The HS contents of the PSU elastomers based on H12MDI and IPDI were systematically varied between 5% and 20% by increasing the ratio of the diisocyanate and the chain extender APTMDS. PSU copolymers of very low urea HS contents (1.0–1.6%) were prepared without the chain extender. All PSU elastomers and copolymers exhibited good elastomeric properties and displayed elongation at break values between 600% and 1100%. The PSUs with HS contents below 10% were transparent and became increasingly translucent at HS contents of 15% and higher. The Young’s modulus (YM) and ultimate tensile strength values of the elastomers increased linearly with increasing HS content. The YM values differed significantly among the PSU copolymers depending on the symmetry of the diisocyanate. The softest elastomer was that based on the asymmetric IPDI. The elastomers synthesized from H12MDI and MDI both exhibited an intermediate YM, while the stiffest elastomer, i.e., that comprising the symmetric CHDI, had a YM three-times higher than that prepared with IPDI. The PSUs were subjected to load–unload cycles at 100% and 300% strain to study the influence of HS morphology on 10-cycle hysteresis behavior. At 100% strain, the first-cycle hysteresis values of the IPDI- and H12MDI-based elastomers first decreased to a minimum of approximately 9–10% at an HS content of 10% and increased again to 22–28% at an HS content of 20%. A similar, though less pronounced, trend was observed at 300% strain. First-cycle hysteresis among the PSU copolymers at 100% strain was lowest in the case of CHDI and highest in the IPDI-based elastomer. However, this effect was reversed at 300% strain, with CHDI displaying the highest hysteresis in the first cycle. In vitro cytotoxicity tests performed using HaCaT cells did not show any adverse effects, revealing their potential suitability for biomedical applications.
KW  - segmented polyurea elastomers
KW  - poly(dimethylsiloxane)
KW  - structure-property relationship
KW  - diisocyanate structure
KW  - transparency
KW  - mechanical properties
KW  - tensile hysteresis
KW  - in vitro cytotoxicity
KW  - biomedical applications
KW  - biomaterials
Y1  - 2021
UN  - https://nbn-resolving.org/urn:nbn:de:bsz:rt2-opus4-30814
SN  - 2073-4360
SS  - 2073-4360
U6  - https://doi.org/10.3390/polym13020212
DO  - https://doi.org/10.3390/polym13020212
VL  - 13
IS  - 2
SP  - 1
EP  - 37
S1  - 37
PB  - MDPI
CY  - Basel
ER  -