The influence of micro-graphite addition on nucleation efficiency and isothermal crystallization kinetics of thermoplastic polyurethane (TPU)

Publication date: Available online 23 January 2020Source: Materials Today: ProceedingsAuthor(s): Kavita A. Deshmukh, Pranjali Khajanji, Swamini Chopra, Abhay Deshmukh, D.R. PeshweAbstractOne of the key requirements in semi-crystalline polyester based polymers is to understand the mechanisms to achieve the level of control on crystallization rate and nucleation efficiency; which is one of the challenges in crystallization kinetics. Thus, in present study the thin films of Thermoplastic Polyurethane (TPU) with addition of micro-graphite were prepared via solution method and significant changes observed in the structural, mechanical and thermal properties due to accelerated rate of nucleation were investigated. Paper mainly focuses on the overall isothermal crystallization kinetics using Polarized Light Optical Microscopy (PLOM) which is supported by Avrami model. The influence of different weight % addition of graphite on nucleation efficiency of TPU has been examined by Differential Scanning Calorimetry (DSC). It was observed through XRD, DSC and PLOM that addition of graphite significantly affects the crystallite size, crystallinity and nucleation density of TPU. Spherulite formation because of selectively preferential nature of graphite to attract the hard segment of TPU over the soft segments was observed from PLOM and SEM and was indeed predicted by Young’s equation. The graphite acts as a strong heterogeneous nucleating agent which induces incision and formation of new ...
Source: Materials Today: Proceedings - Category: Materials Science Source Type: research