Layer multiplication co-extrusion of cross-linked polymer microsphere-filled systems

Layer multiplication co-extrusion allows for creation of advance structures with highly tunable properties, with relative ease. Multi-layer co-extrusion using the layer multiplication technique was used to create 33-layered structures of polymer microsphere-filled layers alternating with unfilled layers. Cross-linked polyurethane (PU) microspheres (of two different rigidities) and ultra-highly cross-linked polymethylmethacrylate (PMMA) microspheres were used to examine the effect of particle rigidity in confinement on overall mechanical properties. Layer structures were successfully created with particle-filled layers; once layer size approaches the particle size, the particles deform the unfilled counter-layer. In certain conditions, impingement of the counter-layer occurs, decreasing the mechanical properties. High-density polyethylene-grafted-maleic anhydride (HDPE-g-MA) was subsequently utilized as a compatibilizer to improve the interface between the particles and the matrix. The HDPE-g-MA was effective in increasing the mechanical performance of the co-extruded product made with the PU microspheres but inefficient in improving the product made with the PMMA microspheres.