双酚A型氰酸酯/端羧基丁腈橡胶共混物的制备工艺和性能

 采用液体端羧基丁腈橡胶(CTBN)与氰酸酯树脂(BCE)共混以改善氰酸酯树脂的韧性,利用凝胶时间法、示差扫描量热法(DSC)和傅立叶红外光谱法(FTIR)确定BCE/CTBN的固化工艺,通过透射电子显微镜对微相结构进行了分析,研究了不同制备工艺对改性后树脂体系微相结构和力学性能的影响规律。结果表明,分别采用固化前对BEC/CTBN施加高速剪切力和预聚氰酸酯的方法可有效解决CTBN增韧BCE树脂中存在的宏观相分离问题;施加高速剪切力后,体系(每100份BCE中含10份CTBN)冲击韧性可达到14.4kJ·m^-2,比改性前(冲击韧性为6.0kJ·m^-2)提高了140%;预聚氰酸酯后,体系冲击韧性可达到12.1kJ·m^-2,比改性前提高了102%。研究还发现,工艺改进后,共混体系中以分散相存在的CTBN粒子形成胞状结构,这些含有包埋物的胞状CTBN颗粒有利于提高BCE树脂基体的韧性和强度。

Curing Process and Properties of BCE/CTBN Blends

Carboxyl terminal functionality on liquid butadiene-acrylonitrile(CTBN) is used to improve the mechanical properties of cyanate ester resin by blending with bisphenol A dicyanate ester(BCE).The curing process is based on gel time of BCE/CTBN blends and analysis of differential scanning calorimetry(DSC) and Fourier transform infrared(FTIR).The influence of curing process on structures and properties of BCE/CTBN are studied.Morphology of broken specimens are examined by transmission electron microscopy(TEM).Firstly,it is shown that macroscopical phase separation of BCE/CTBN blends can be improved by two ways,which are applying fast force to the BCE/CTBN blends and pre-polymerizing the BCE before curing process.Secondly,the modified system shows much higher impact thoughness.The two ways mentioned above lead to 140% and 102% increase in impact thoughness,respectively.Thirdly,it is shown that the modified system includes typical cystiform CTBN particulates,which is beneficial to increasing the flexural strength and impact thoughness of BCE.