Melt processing and domain morphology of PMMA/HDPE polymer blends prepared from powder precursors

Powder polymer processing was used to prepare immiscible PMMA/HDPE blends from micrometer sized polymer spheres that were physically mixed prior to compression molding to a fused blended film. This two-stage mixing approach, initially as dry powders and subsequently during compression molding, seeks to minimize the time/temperature/shear to which delicate thermoplastic polymers would otherwise be exposed by conventional extrusion processing. The powder processing route effectively generates fine domain blends (3–10 μm) similar to extruded blends, although some coalescence was present. Conformational effects were observed by FTIR at high wavenumbers, indicating intimate interfacial proximity. The spectral effects are similar to those observed in extruded pellet blends. This powder processing route will be useful for molding delicate thermoplastic polymers found in certain biomaterial, pharmaceutical, and cosmetic applications.

EDS chemical analysis was used to differentiate the domains present in the immiscible polymer blend of PMMA/HDPE. The outlined material was identified and image analysis was performed and subsequently plotted to qualitatively express the domain sizes of the blend. FTIR analysis was employed to identify perturbations at the domain interfaces.Figure optionsDownload as PowerPoint slideHighlights
► Fine polymer powders of PMMA and HDPE were blended and compression molded.
► Premixing minimizes the temperature, shear rate, and time of melt processing.
► Domain sizes of the powdered blends are comparable to extruded composites.
► FTIR spectra indicate conformational effects and good interfacial proximity.
► The powder route enables melt processing of fragile thermoplastic polymers.