Viscoelastic properties and morphology of dicyanate ester/epoxy co-polymers modified with polysiloxane and butadiene–acrylonitrile rubbers

Urszula Szeluga,Paweł Moryc

doi:10.1007/s10973-012-2899-9

Abstract

Dynamic mechanical analysis was conducted on specimens prepared from cyanate ester (CE) and epoxy (EP) resins cured together at various mass compositions. Increase of amount of epoxy resin in composition was shown to have a disadvantageous effect on glass transition temperature (Tg). It was shown that post-curing procedure was needed to produce a polymer matrix with a single glass transition relaxation, but increase in post-cure temperature up to 250 °C resulted in slight reduction in Tg for epoxy/cyanate copolymers. TG results proved that the presence of epoxy resin reduces thermal stability of the cyanate/epoxy materials. The neat CE and EP/CE systems containing 30 wt% of epoxy resin were modified using epoxy-terminated butadiene–acrylonitrile rubber (ETBN) and polysiloxane core–shell elastomer (PS). The scanning electron microscopy (SEM) results showed the existence of second phase of ETBN and PS modifiers. Only in the case of EP/CE composition modified with ETBN, well-dispersed second phase domains were observed. Analysis of SEM images for other CE- and EP/CE-modified systems revealed the formation of spherical aggregates.

Highlights

Polycyanurates are interesting polymers used in the area of aerospace structures, dielectrics, aircraft, and others requiring special materials
The maximum degradation temperatures (Tm) of the epoxy/cyanate matrices with 30, 50, and 70 wt% epoxy resin are lower than that of neat cyanate. These results prove that the presence of epoxy resin reduces thermal stability of the cyanate materials containing addition of epoxy
The results of the dynamic mechanical analysis (DMA) testing showed that the neat cyanate resin had better thermal properties, showing a higher glass transition temperature, Tg, than its mixtures with epoxy resin

Summary

Introduction

Polycyanurates are interesting polymers used in the area of aerospace structures, dielectrics, aircraft, and others requiring special materials. It was shown that post-curing procedure was needed to produce a polymer matrix with a single glass transition relaxation, but increase in post-cure temperature up to 250 °C resulted in slight reduction in Tg for epoxy/ cyanate copolymers.

Results

Conclusion