Influence of Hard Segments on the Thermal, Phase-Separated Morphology, Mechanical, and Biological Properties of Polycarbonate Urethanes

Rong Zhu,Yiyu Wang,Yi Li,Xinyu Wang,Zongrui Zhang,Jing Yang,Fei Lin,Yuanjing Hou

doi:10.3390/app7030306

Abstract

In this study, we have fabricated a series of polycarbonate polyurethanes using a two-step bulk reaction by the melting pre-polymer solution-casting method in order to synthesize biomedical polyurethane elastomers with good mechanical behavior and biostability. The polyurethanes were prepared using dibutyltin dilaurate as the catalyst, poly(1,6-hexanediol)carbonate microdiols (PCDL) as the soft segment, and the chain extender 1,4-butanediol (BDO) and aliphatic 1,6-hexamethylene diisocyanate (HDI) as the hard segments. The chemical structures and physical properties of the obtained films were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, gel permeation chromatography (GPC), differential scanning calorimeter (DSC), and mechanical property tests. The surface properties and degrees of microphase separation were further analyzed by water droplet contact angle measurements (CA) and atomic force microscopy (AFM). The materials exhibited a moderate toxic effect on the tetrazolium (MTT) assay and good hemocompatibility through hemolytic tests, indicating a good biocompatibility of the fabricated membranes. The materials could be considered as potential and beneficial suitable materials for tissue engineering, especially in the fields of artificial blood-contacting implants or other biomedical applications.

Highlights

Biomedical polyurethane devices, because of their excellent mechanical flexibility, chemical resistance, and good biocompatibility [1,2,3,4], have been deeply investigated and widely used in the medical fields of both engineering and countless biomedical consumer products such as artificial hearts, catheters, injectable gels, pacemaker leads, and biodegradable scaffolds [5,6,7,8,9]
N,N-dimethyl acetamide (DMAc), tetrahydrofuran (THF), dibutyltin dilaurate, and diethyl ether were all purchased from Sinopharm Chemical Reagent Co., Ltd
The range of the number-average molecular weight was 0.88 × 104 –2.66 × 104 Da with the molecular weight distributions between 1.20 and 1.68, indicating that the molecular weight becomes better with a better distribution with increasing the hard segment

Summary

Introduction

Biomedical polyurethane devices, because of their excellent mechanical flexibility, chemical resistance, and good biocompatibility [1,2,3,4], have been deeply investigated and widely used in the medical fields of both engineering and countless biomedical consumer products such as artificial hearts, catheters, injectable gels, pacemaker leads, and biodegradable scaffolds [5,6,7,8,9]. Most polyurethanes are multiblock co-polymers commonly consisting of hard and soft segments. For these types of materials, the various thermal and mechanical properties are determined by these alternating segments, repeating units of urethane linkages made by the reaction of an isocyanate with hydroxyl in polyurethanes, and especially the strong intermolecular forces of the hard domains [10,11]. The elastic deformability of elastomers is of great importance for all kinds of polyurethanes. Their available properties are directly related to the two phase microphase separation morphology caused by their unique structure of alternating hard and soft segments [15]. Investigators have devoted themselves to this field for at least fifty years, and have made great strides in understanding their excellent properties, attributed to their synthetic methods and chemical structures [16,17]

Methods

Results

Conclusion