On a novel method to synthesize POSS-based hybrids: An example of the preparation of TPU based system

• Main Authors: O. Monticelli, A. Fina, D. Cavallo, E. Gioffredi, G. Delprato
• Format: Article
• Language: English
• Published: Budapest University of Technology 2013-12-01
• Series: eXPRESS Polymer Letters
• Subjects: Nanocomposites; POSS; TPU
• Online Access: http://www.expresspolymlett.com/letolt.php?file=EPL-0004679&mi=cd

A novel method to prepare polymer/polyhedral oligomeric silsesquioxanes (POSS) hybrids by melt reactive blending is proposed in this paper, by the controlled polymer chain scission and reaction of chain ends with functional silsesquioxanes. Application to thermoplastic polyurethanes (TPU) is addressed, taking advantage of the polyurethane chain scission equilibrium reaction, leading to the formation of highly reactive isocyanate and hydroxyl chain ends. Despite the isocyanate chemistry has been widely studied for the preparation of polymer/POSS hybrids by in situ copolymerisation, the exploitation of similar chemical processes in an industrially viable and environmental friendly melt blending process is currently an open research field. In this work, the reaction in the molten state of dihydroxyl-functionalised POSS with the polyurethane chain is demonstrated to produce a TPU/POSS hybrids. The effect of POSS concentration on nanomorphology, thermal properties and surface properties is studied, showing significant changes compared to pristine TPU. In particular, an increase of glass transition temperature is observed in the presence of reactive POSS (ΔT up to about 10°C in the presence of 10 wt% loading). Furthermore, an increase of surface water wettability, evidenced by the decrease of water contact angle from 95° for pristine TPU to 70° in TPU containing 10"wt% of reactive POSS, is found.