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

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 (T g ). 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 T g 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.

Toughening epoxy resin with blocked isocyanate containing soft chain

“…The morphology pattern of MI cured epoxy [Figure (a)] showed smooth and MI‐ b ‐TDI cured E‐44 showed glassy fractured surfaces with ripples [Figure (b)]. PEG‐MI‐ b ‐TDI cured E‐44 showed very rough [Figure (c,d)] . When PEG content was 1% [Figure (c)], the whole systems were a homogeneous phase structure.…”

Influence of electron beam irradiation on extracellular matrix of the human allogeneic skin grafts

“…Samples from control group and 18 kGy group were more elastic than samples after treatment using higher irradiation doses (25 and 35 kGy). Although DMA is considered the most suitable technique for testing different types of materials, [47][48][49] it is also suitable for monitoring the viscoelastic behavior of human allogeneic skin grafts.…”

Structural and Thermal Properties of Ethylene-Norbornene Copolymers Obtained Using Vanadium Homogeneous and SIL Catalysts

“…Copolymer microstructure and properties are tightly connected with conditions of reaction and type of catalyst. Nowadays, interest in vanadium complexes is currently growing because they enable to obtain polymers of high molecular weight ( M w ) and narrow molecular weight distribution ( M w /M n ), copolymers of ethylene with higher 1-olefins or cyclic olefins with high comonomer incorporation in the copolymer chain [ 1 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. However, a big disadvantage of vanadium compounds is their instability, they are easily reduced to lower, inactive oxidation state.…”