Preparation and Characterization of Biodegradable Polyurethane Composites Containing Attapulgite Nanorods

Abstract

In this study, polyurethane (PU) is synthesized using 4,4,-diphenylmethane diisocyanate as the hard segments and polytetramethylene glycol and polycaprolactone diol as the soft segments. In addition, attapulgite (AT)/PU nanocomposites are prepared by adding AT into PU matrix. The structure and morphology of AT/PU nanocomposites are examined using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDS). The TEM results show that AT maintains its rod-like structure in the PU matrix. The FT-IR results show that there is no significant change in the FT-IR spectrum after a small amount of AT is added into the PU matrix. The XRD results show that the main crystallization peaks of AT become more apparent with increasing AT content, and the EDS results show that the intensity of the Si peak also increases with increasing AT content. In addition, the mapping shows that AT nanorods are poorly dispersed when the AT content reaches 5 wt%. The thermal and mechanical properties of the AT/PU nanocomposite with an AT content of 2 wt% are optimal, and when the AT content surpasses 5 wt%, an aggregation phenomenon occurs, resulting in reductions in the thermal and mechanical properties of the AT/PU nanocomposite. The contact angle test and atomic force microscopy results show that the surface of the nanocomposite becomes more rough and hydrophobic with increasing AT content. The scanning electron microscopy observations of the hydrolytic degradation of the AT/PU nanocomposites show that their hydrolytic degradation was affected by the test temperature, test time, and AT content. The moisture absorption test shows that the moisture absorption of the AT/PU nanocomposite increases with increasing AT content and ambient humidity.