Polyimide Aerogels Cross-Linked with Aminated Ag Nanowires: Mechanically Strong and Tough.

Tianyi Zhang,Yan Zhao,Kai Wang

doi:10.3390/polym9100530

Abstract

In this study, polyimide (PI)/Ag nanowire (AgNW) nanocomposite aerogels with extremely high mechanical performance have been fabricated utilizing amine-modified AgNWs as mechanical nanoreinforcement particulates and crosslinking agents. Initially, AgNWs were fabricated and surface modified by p-aminothiophenol (PATP), then the aminated AgNWs were dispersed into polyamide acid solution and aerogels were prepared by supercritical CO2 drying. Raman and X-ray photoelectron spectroscopy (XPS) spectrometry were carried out on A-AgNWs (aminated Ag nanowires) to prove the successful modification. This functional nanoparticle greatly enhanced the strength and toughness of aerogels without evident increase in densities. Comparing to pure PI aerogels, samples with 2.0 wt % of A-AgNWs had a 148% increase in compression strength and 223% increase in Young’s modulus, which equates to 2.41 and 27.66 MPa, respectively. Simultaneously, the tensile test indicated that aerogels with 2.0 wt % of A-AgNWs had a breaking energy of 40.18 J/m3, which is 112% higher than pure PI aerogels. The results presented herein demonstrate that aminated AgNWs are an innovative cross-linker for PI aerogels and can improve their strength and toughness. These aerogels have excellent potential as high-duty, lightweight porous materials in many areas of application.

Highlights

As one of the most popular organic aerogels, polyimide (PI) aerogels have attracted considerable attention in recent years
Surface appearance showed hardly after the modification, Raman spectromentry and X-ray photoelectron spectroscopy (XPS) are required to further verify the any change after the modification, Raman spectromentry and XPS are required to further existence of PATP on the surface of A-Ag nanowires (AgNWs) as well as their binding state
Polyimide aerogels cross-linked with aminated Ag nanowires (A-AgNWs) were prepared by Polyimide aerogels aerogels cross-linked cross-linked with with aminated aminated Ag

Summary

Introduction

As one of the most popular organic aerogels, polyimide (PI) aerogels have attracted considerable attention in recent years. Comparing to the conventional silica aerogels [1,2], PI aerogel possesses the typical properties of aerogels [3], such as low density, high porosity, good insulativity and small pore size [4], and shows the excellent advantage of flexibility [5], combined with outstanding thermostability and fire resistance [5] unlike other conventional polymer aerogels [6], such as syndiotactic polystyrene [7], polyurethane [8,9,10], polyurea, cellulose [11], poly(vinyl alcohol) [12], polyamide [13,14], chitin [15] etc. The results showed that the density of the PI aerogel could be as low as 0.14 g/cm and the specific surface area could be as high as 512 m2 /g.

Methods

Results

Conclusion