Influence of the Organoclay Content on the Structure, Morphology, and Surface Related Properties of Novel Poly(dimethylsiloxane)-Based Polyurethane/Organoclay Nanocomposites

• Published in: Industrial & engineering chemistry research 2017-05, Vol.56 (17), p.4970-4983
• Main Authors: Pergal, Marija V, Stefanović, Ivan S, Poręba, Rafał, Steinhart, Miloš, Jovančić, Petar, Ostojić, Sanja, Špírková, Milena
• Format: Article
• Language: English
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.6b04913

Novel poly­(dimethylsiloxane)-based polyurethane nanocomposites (TPU-NCs) were synthesized using in situ polymerization with the nanoclay Cloisite 30B. Differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical thermal analysis showed that TPU-NCs with an organoclay content of ≤5 wt % exhibited increased thermal stability, storage modulus, and hard-segment melt temperatures but decreased degrees of crystallinity. TPU-NCs displayed increased surface hydrophilicity and enhanced surface free energy with increasing organoclay content. Small- and wide-angle X-ray scattering confirmed intercalated formations of organoclays in the nanocomposites. Individual clay particles on the surfaces of TPUs with lower organoclay loadings (1 or 3 wt %) or organoclay agglomerates in TPUs with higher amounts of organoclay (≥5 wt %) were detectable using scanning electron microscopy. The relatively smooth and homogeneous character of pure TPU and the distinctly heterogeneous and rough surfaces of TPU-NCs were detected via atomic force microscopy. Among the nanomaterials prepared, TPU-NCs with 1 wt % organoclay provided the best balance between the organoclay concentration and the functional properties desired in biomedical applications.