Study On Modification Of Cyanate Resin By Liquid Butadiene-acrylonitrile Rubbers

Cyanate ester (CE) resins are among the most important engineering thermosetting polymers and have received attention because of their outstanding dielectric, mechanical and processing properties. However their main drawback is brittleness. The liquid butadienecrylonitrile rubber has been proved to be the most effective toughener for cyanate ester resin. The toughness of CE blends depends on the content, molecular weight, acrylonitrile content and the functional terminated group of the liquid butadiene-acrylonitrile rubber. Former researches only involved in the different toughening effects affected by various content of liquid butadiene-acrylonitrile rubber in the blends.This work mainly focuses on the different modification effects caused by addition of carboxyl terminated liquid butadiene-acrylonitrile rubber (CTBN) with different acrylonitrile content and liquid butadiene-acrylonitrile rubber with different functional terminated groups. The phase separation, morphology of fracture surface and physical properties of the blends are studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA).It is testified that the compatibility and toughness between CE and CTBN had a positive correlation with the acrylonitrile content of CTBN. The different compatibility between CE and CTBN induce different phase structure and morphology of the blends. When the acrylonitrile content of CTBN in the blends increases, the compatibility between CE and CTBN becomes better and the impact strength of the blends is improved at the same time. The different compatibility between CE and CTBN caused by various acrylonitrile content in liquid carboxyl terminated rubber also affect the dynamic mechanical and thermal properties of the blends. The initial storage modulus of the blends increases but the thermal stability of the blend deteriorates when the acrylonitrile content increases.It is also concluded that the compatibility between CE and of liquid butadiene-acrylonitrile rubber varied by different active terminated groups. Thecompatibility between CE and CTBN is much better than that between CE and the amine terminated butadienecrylonitrile rubber(ATBN). The different compatibilities caused by various active terminated groups of liquid butadiene-acrylonitrile rubbers also induce different phase structure and morphology, modification effects, dynamic mechanical properties of CE/CTBN and CE/ATBN blends. But the thermo stability of CE/liquid butadiene-acrylonitrile rubber blend isn't affected by various terminated groups.