Mechanically Robust Hybrid POSS Thermoplastic Polyurethanes with Enhanced Surface Hydrophobicity

Abstract

A series of hybrid thermoplastic polyurethanes (PUs) were synthesized from bi-functional polyhedral oligomeric silsesquioxane (B-POSS) and polycaprolactone (PCL) using 1,6-hexamethylene diisocyanate (HDI) as a coupling agent for the first time. The newly synthesized hybrid materials were fully characterized in terms of structure, morphology, thermal and mechanical performance, as well as their toughening effect toward polyesters. Thermal gravimeter analysis (TGA) and differential scanning calorimetry (DSC) showed enhanced thermal stability by 76 °C higher in decomposition temperature (Td) of the POSS PUs, and 22 °C higher glass transition temperature (Tg) when compared with control PU without POSS. Static contact angle results showed a significant increment of 49.8° and 53.4° for the respective surface hydrophobicity and lipophilicity measurements. More importantly, both storage modulus (G’) and loss modulus (G’’) are improved in the hybrid POSS PUs and these parameters can be further adjusted by varying POSS content in the copolymer. As a biodegradable hybrid filler, the as-synthesized POSS PUs also demonstrated a remarkable effect in toughening commercial polyesters, indicating a simple yet useful strategy in developing high-performance polyester for advanced biomedical applications.

Hybrid nanocomposites of elastomeric polyurethane containing halloysite nanotubes and POSS nanoparticles: tensile, hardness, damping and abrasion performance

“…The improvement in mechanical performance of TPU following the inclusion of HNT and modified POSS in smaller amounts resulted from the enhanced compatibility between the polymer matrix and surfaces of the additives. Previous work has shown that surface free energies of TPU, aminopropylisobutyl-POSS and HNT are ~40 mJ/m 2 (Pötschke et al , 2002; Król & Król, 2012; Primel et al , 2017; Díez-García et al , 2020), 60 mJ/m 2 (Turri & Levi, 2005; Misra et al , 2007; Song et al , 2019; Zhang et al , 2019), and 50 mJ/m 2 (Hope & Kittrick, 1964; Owoseni et al , 2015; Cheng et al , 2018), respectively. The narrow range of surface-energy values between phases creates strong adhesion of fillers to the TPU matrix.…”

“…Improvement of mechanical performance of TPU by the inclusion of HNT and modified POSS with their lower amounts was arising from the enhanced compatibility between polymer matrix and additive surfaces. According to literature, surface free energies of TPU, aminopropylisobutyl-POSS and HNT are nearly 40 mJ/m 2 (Díez-García et al, 2020;Król & Król, 2012;Pötschke et al, 2002;Primel et al,2017), 60 mJ/m 2 (Misra et al, 2007;Song et al, 2019;Turri & Levi, 2005;Zhang et al, 2019), and 50 mJ/m 2 (Cheng et al, 2018;Hope & Kittrick, 1964;Owoseni et al,2015), respectively. The narrow range of surface energy values between phases donates strong adhesion of fillers to TPU matrix.…”

POSS Compounds as Modifiers for Rigid Polyurethane Foams (Composites)

“…Hybrid nature and nanometric size scale make silsesquioxanes extremely attractive materials used as nanofillers [45]. It was shown in previous studies that the introduction of POSS compounds to the polymeric material may increase the temperature of use and decomposition, affect the glass transition temperature, increase the resistance to oxidation of the composite, improve mechanical strength, affect surface hardening, reduce flammability and heat [43,46,47].…”

Molecular structure development in silsesquioxane−urethane thin film hybrids: A small‐angle neutron scattering investigation

“…Not surprisingly, significant property enhancements have been reported for some of these POSS hybrid systems, including increased toughness, decreased flammability, high ultraviolet stability, and increased oxidation resistance. To date, POSS molecules have been successfully incorporated into many pure organic polymer systems, including epoxies, imides, methacrylates, cyanates and rubber compounds, as well as urethanes …”