The effect of polyhedral oligomeric silsesquioxane fillers in non‐isocyanate polyurethane hybrid resins

Abstract

Polyhedral oligomeric silsesquioxane (POSS) is added to poly(hydroxyurethane) (PHU) prepolymers to create hybrid PHUs (HPHUs) with enhanced mechanical and thermal properties. These hybrid materials were then further functionalized with 3‐Isocyanatopropyl(trimethoxy) silane (IPTMS) via the pendent hydroxyl bonds within the backbone of the polymers to obtain a final cured film comparable to conventional polyurethanes (PU), using less isocyanate‐functional material. The incorporation of POSS into PHU prepolymers to obtain HPHUs was supported by gel permeation chromatography, fourier tranform infrared spectroscopy (FTIR) and nuclear magnetic resonance analysis. Furthermore, the thermal degradation of the HPHUs was significantly improved with increasing POSS concentration compared to their PHU counterparts as the degradation temperatures at 50% weight loss increased from 263°C for the PHU to 341°C for the HPHU. Gel content tests in tetrahydrofuran (THF), water, and toluene were performed and gel contents of 87%–99% in THF were observed for the cured films. Water swelling, and contact angle tests confirmed that the POSS‐modified films exhibited hydrophobic behavior. Finally, mechanical properties of the cured films were investigated. The Young's modulus and tensile strength were improved with increasing POSS concentration (from 2.0 to 3.1 MPa and from 0.82 to 1.32 MPa, respectively) and elongations at break up to 41.6% were observed. When compared to a conventional PU sealant, the HPHU achieved a tensile strength that was two‐fold greater and a comparable elongation at break (increasing from 24.8% to as high as 41.6%).

AB-type monomer of polyhedral oligomeric silsesquioxane

“…2 Among these, the cage-type silsesquioxane, known as polyhedral oligomeric silsesquioxane (POSS), stands out for its suitability for precise molecular design. 3 Polymers containing POSS are typically categorized into four types based on the point of introduction: main chains, 4 side chains, 5 end points, 6 and cross-linking points. 7 Of these, main chain-type POSS polymers have garnered significant attention owing to their superior performance and distinctive properties.…”

Examining the Water–Polymer Interactions in Non-Isocyanate Polyurethane/Polyhedral Oligomeric Silsesquioxane Hybrid Hydrogels

“…Generally, the physical blending of POSS in a polymer matrix is associated with partial agglomeration of POSS since there is a high surface free energy and a high affinity of nanoparticles [35][36][37]. As the modification of polyurethanes leads to advantageous results, the impact o different types of additives on the properties of NIPUs has been studied [15][16][17][18][19], includin polyhedral oligomeric silsesquioxanes (POSS) [20][21][22][23][24]. POSS consists of a group of hybrid (organic/inorganic) molecules that are characterized by a well-defined silica cage core tha is usually functionalized by reactive or non-reactive substituents (Figure 2) [25].…”

“…Recent studies on NIPU modification with POSS focus mainly on systems wher POSS is introduced covalently into the polymer chain [3,[20][21][22][23][24][43][44][45][46][47][48][49]. The impact o chemically incorporated POSS in such systems on mechanical and thermal properties ha As the modification of polyurethanes leads to advantageous results, the impact of different types of additives on the properties of NIPUs has been studied [15][16][17][18][19], including polyhedral oligomeric silsesquioxanes (POSS) [20][21][22][23][24]. POSS consists of a group of hybrid (organic/inorganic) molecules that are characterized by a well-defined silica cage core that is usually functionalized by reactive or non-reactive substituents (Figure 2) [25].…”

“…As the modification of polyurethanes leads to advantageous results, the impact of different types of additives on the properties of NIPUs has been studied [ 15 , 16 , 17 , 18 , 19 ], including polyhedral oligomeric silsesquioxanes (POSS) [ 20 , 21 , 22 , 23 , 24 ]. POSS consists of a group of hybrid (organic/inorganic) molecules that are characterized by a well-defined silica cage core that is usually functionalized by reactive or non-reactive substituents ( Figure 2 ) [ 25 ].…”

“…Recent studies on NIPU modification with POSS focus mainly on systems where POSS is introduced covalently into the polymer chain [ 3 , 20 , 21 , 22 , 23 , 24 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ]. The impact of chemically incorporated POSS in such systems on mechanical and thermal properties has been widely studied.…”