反应性树脂体系化学增黏和物理减黏机制的分离

采用等温差示扫描量热(DSC)法,研究了CTD-128环氧树脂与GA-327(DDM改性芳胺)的固化度-时间变化关系;采用AR2000EX型旋转流变仪,测试了上述体系的等温黏度-时间关系.比较等温条件下的固化度-时间关系和黏度-时间关系,建立了等温条件下的黏度-固化度的等时对应关系,结果表明在纯化学增黏机制影响下,树脂体系的黏度随固化度增加先缓慢增加,当固化度增大到一定程度后黏度快速增加.将等温条件下的黏度-固化度关系进行变换,得到恒定固化度下的黏度-温度关系,揭示了在物理减黏机制影响下,树脂体系黏度随温度的增加而降低,并且黏度降低幅度随固化度的增加而增大.两种黏度影响机制分离的实现,为反应性树脂体系实时黏度的准确预测提供了技术支持.

Separation of Chemical Mechanism of Viscous Increase and Physical Mechanism of Viscous Falling for Reactive Resin System

The isothermal differential scanning calorimetry (DSC) method was used to determine the relationship between curing degree and time of a epoxy resin of CYD-128 with GA-327 as curing agent. An AR 2000EX rolling rheometer was used to measure the resin viscosity in a range of isothermal temperatures. Comparing the isothermal conversion-time relation with that of the isothermal viscosity-time, the isochronous relation of the isothermal viscosity-conversion was set up correspondingly. Results suggest that under the individual influence of the chemical mechanism of viscous increase, the viscosity of the resin system slowly increases with the ineresse of isothermal conversion, and then increases quiddy when the conversion reaches a certain extent. Changing the isothermal viscosityconversion relation to the relation of viscosity-temperature under the constant conversion, it shows that under the individual influence of the physical mechanism of viscous falling, the resin viscosity decreases with the temperature increased, and the viscosity descendent extent of the resin system increases with the conversion increased. These two mechanisms are separated from each other, which is the technical base of the accurate prediction for the reactive resin system,