Phase Separation and Rheological Behavior of Rubber-Modified Systems

Phase Separation and Rheological Behavior of Rubber-Modified Systems 

As the stmcture-property relationship was more involved during the early stages of these studies, rheological measurements were always applied as an auxiliary method. An example was that of Pucdariello et al. [43], who used a rheological method to monitor the gel time of mbber-modified epoxy resins. 

Kwak et al. [44] used an isothermal steady shear test to monitor the copolymerization of sUoxane-containing oligomers and diglycidylether of bisphe-nol A (DGEBA) epoxy. The gel time of the blends was obtained from values of the storage modulus (G ) and loss modulus (G ). Based on the concept of Eq. (4.3), 

Mondragon et al. [45] were the first to conduct a systematic study of rubber-modified systems, in which a liquid elastomer poly(oxypropylentriamine) (POPTA) was used to modify a DGEBA epoxy. Based on the concept that the relative concentrations of both the epoxy monomer and the hardeners may differ from that in the initial formulation (which leads to a departure from stoichiometry), these authors studied the kinetics and rheology of systems with different ratios of epoxies to hardeners. 

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