Thermoplastic Polymers with Nanosilver Addition-Microstructural, Surface and Mechanical Evaluation during a 36-Month Deionized Water Incubation Period.

Magdalena Ziąbka,Michał Dziadek

doi:10.3390/ma14020361

Abstract

Three types of thermoplastic polymers, acrylonitrile butadiene styrene (ABS), polymethyl methacrylate acrylic (PMMA) and high-density polyethylene (HDPE), were enriched with silver nanoparticles (AgNPs) of 0.5 wt.% and 1.0 wt.%, respectively. The polymers and the composites were manufactured via injection molding. Regarding the potential of these polymers as matrices for long-term use as biomaterials, the aim of this study was to examine their stability in the in vitro conditions during a three-year incubation period in deionized water. In this work, microstructural observations were performed, and mechanical properties were assessed. Surface parameters, such as roughness and contact angle, were comprehensively investigated. The microstructural evaluation showed that the silver additive was homogeneously dispersed in all the examined matrices. The 36-month immersion period indicated no microstructural changes and proved the composites’ stability. The mechanical tests confirmed that the composites retained comparable mechanical properties after the silver incorporation. The Young’s modulus and tensile strength increased during long-term incubation. The addition of silver nanoparticles did not alter the composites’ roughness. The contact angle increased with the rising AgNP content. It was also shown that the materials’ roughness increased with the incubation time, especially for the ABS- and HDPE-based materials. The water environment conditions improved the wettability of the tested materials. However, the silver nanoparticles’ content resulted in the contact angle decreasing during incubation. The conducted studies confirmed that the mechanical properties of all the polymers and composites did not deteriorate; thus, the materials may be considered stable and applicable for long-term working periods in aqueous environments.

Highlights

Synthetic polymers have rapidly entered the medical market due to their advantageous physical, chemical and biological properties, which make them attractive for regenerative medicine, tissue engineering, arthroscopy and joint reconstruction
The microstructural observations of polymers acrylonitrile butadiene styrene (ABS) (Figure 1), Polymethyl methacrylate acrylic (PMMA) (Figure 2) and high-density polyethylene (HDPE) (Figure 3)) and their silver composites showed that all the samples had smooth surfaces, i.e., free of cracks, holes or any other defects
We studied how silver nanoparticle content affected the mechanical properties of ABS/AgNP, PMMA/AgNP and HDPE/AgNP nanocomposites

Summary

Introduction

Synthetic polymers have rapidly entered the medical market due to their advantageous physical, chemical and biological properties, which make them attractive for regenerative medicine, tissue engineering, arthroscopy and joint reconstruction. PMMA is characterized by high values of scratch resistance, a high transparency factor (up to approximately 92% of visible light) and hardness, which makes it applicable in optical products, e.g., lenses and fibers [5] Another example of a chemically and thermally stable polymer is acrylonitrile butadiene styrene (ABS). ABS is commonly used to produce respiratory device infusion systems and autoinjection devices [8] Another example of a thermoplastic polymer applied in biomedicine is High-Density Polyethylene, which is characterized by very good mechanical properties such as high tensile strength, bending and fatigue strength, hardness and appropriate wear resistance, abrasion resistance and a low friction coefficient [9]. This semicrystalline polymer is widely used in the fabrication of medical devices and implants, e.g., in cranial and facial reconstructions and as an acetabular cup for hip replacements [11]

Objectives

Methods

Results

Conclusion