Unsaturated Polyester Resin Nanocomposites Containing ZnO Modified with Oleic Acid Activated by N,N'-Carbonyldiimidazole.

Xiaoxue Tian,Hengzhi Chen,Jing Liu

doi:10.3390/polym10040362

Abstract

Hydrophobic zinc oxide (ZnO) nanoparticles were produced through grafting aminopropyltriethoxysilane (APS) and oleic acid (OA), which was activated by N,N′-carbonyldiimidazole (CDI). The functional group containing ZnO nanoparticles were incorporated into unsaturated polyester (UP) resin, and their dispersibility in the UP matrix and effects on the properties of UP/ZnO nanocomposites were investigated. ZnO nanoparticles modified by APS and OA activated by CDI, (CDI–OA–APS–ZnO), can be homogeneously dispersed as supported by transmission electron microscopy (TEM) investigations and had been encapsulated in the UP resin. CDI–OA–APS–ZnO nanoparticles were embedded in the net structure of the UP composites through chemical bonds between oleic acid, styrene, and polyester resin, which significantly influence the cure reaction of UP resin and the properties of UP composites. Thermogravimetric analysis (TGA) results show that the incorporation of ZnO nanoparticles could improve the thermal stability of UP when thermal cracking temperature exceeds 365 °C. The exothermic peak and the initial temperature of cure reaction of the UP resin decreased with increasing ZnO content. The tensile strength and bending strength of UP/CDI–OA–APS–ZnO nanocomposites increased by 91.4% and 71.3% when 3 wt % CDI–OA–APS–ZnO nanoparticles was added into the composites, respectively, compared with pure UP resin.

Highlights

Unsaturated polyester resins (UPs) are a type of thermosetting resin that are important for their versatility in properties, flexibility in processing, and low cost [1]
The tensile strength and bending strength of UP/CDI–oleic acid (OA)–APS–zinc oxide (ZnO) nanocomposites increased by 91.4% and 71.3% when 3 wt %
The peak at 1510 cm−1 corresponds to the deformation vibration of the NH group of the APS molecule [26], which illuminates that APS was introduced on the surface of the nano-ZnO through chemical bindings, as shown in R1. (Figure 1d) shows the characteristic bands of –COOH and –CH=CH– of OA at 1710 and 1485 cm−1, respectively

Summary

Introduction

Unsaturated polyester resins (UPs) are a type of thermosetting resin that are important for their versatility in properties, flexibility in processing, and low cost [1]. Because of such shortcomings, such as low strength, poor toughness, and large shrinkage, polyester resins should be improved to promote their performance. Scattering inorganic nanoparticles into the polymer is considered an effective measure to promote mechanical properties and heat resistant performance [2,3,4]. Inorganic nanoparticle/polymer composites have received increasing concern and interest in recent years [5,6,7]. ZnO nanoparticles have been widely used in scientific research and practical applications because of their non-toxic nature and ability to block UV radiation

Methods

Results

Conclusion