8 research outputs found
Preparation of thermoset rubbery epoxy particles as novel toughening modifiers for glassy epoxy resins
By curing of in water dispersed droplets of an aromatic or aliphatic epoxy resin, respectively, glassy or rubbery thermosetting epoxy spheres can be prepared in a relatively easy way. The rubbery epoxy particles can successfully be applied as a toughening agent for glassy epoxy matrices. The advantage of these preformed modifiers is the control over the final morphology as the size and concentration of the dispersed rubber phase can be chosen independently. The improvement in fracture toughness and the morphological features of the fracture surfaces are identical to standard, but also more complex, toughening routes, such as the application of liquid rubbers [Sultan JN, Laible RC, McGarry FJ. Appl. Polym. Symp. 1971;16:127; Sultan JN, McGarry FJ. Polym. Eng. Sci. 1973;13:29]. The use of this new class of rubber modifiers is not restricted to glassy epoxy resins, but may also be applied to produce impact-modified thermoplastics with a predetermined particle size and rubber content
Microphase separation:enabling isosorbide-based polycarbonates with improved property profile
\u3cp\u3eMicrophase separation of bio-based soft blocks in a hard isosorbide polycarbonate enabled the preparation of a transparent bio-based engineering plastic with improved mechanical properties and processability at milder conditions. The ability to process these isosorbide-containing polycarbonates at lower temperatures in combination with a lower polymerization temperature due to the use of the activated bis(methyl salicyl) carbonate as the carbonate source avoided the undesired elimination of β-hydrogens, which is commonly observed in isosorbide-containing polymers. Preparation of a wide range of custom samples with varying combinations of soft blocks, followed by characterization and statistical analysis, enabled the identification of the correlations between composition and mechanical and thermal properties, resulting in an optimized engineering plastic with facile processing, transparency, and ductility combined with >84% renewable content.\u3c/p\u3