RESUMEN
Recycling mixed polyolefin plastics is a significant challenge due to the limitations in sorting and degraded mechanical properties of blends. Nonreactive compatibilization by adding a small amount of polymeric additive is a widespread approach to restoring the performance and value of recycled plastics. Over the past several decades, synthetic advances have enabled access to low-cost copolymers and precision architectures for deepening the understanding of compatibilization mechanisms in semicrystalline polyolefins. This review covers the design parameters of a polymeric compatibilizer, the testing of blends, the synthetic methods of producing economically viable additives, and surveys the literature of blends of compatibilized HDPE, LLDPE, LDPE, and iPP. From this, readers should gain a comprehension of the polymer mechanics, synthesis, and macromolecular engineering of processable polyolefin blends, along with the field's future directions.
RESUMEN
High-density polyethylene (HDPE) is utilized in a multitude of commercial products worldwide due to its broad spectrum of physical properties and low production costs. Molecular weight and dispersity (D) are known to affect the tensile and rheological properties of HDPE, but little is known about the influence of the molecular weight distribution (MWD) shape on these properties. In this work, we investigate this matter through the temporal regulation of initiation in a living coordination-insertion polymerization of ethylene. This method provides precise control over the MWD shape which, in turn, offers a systematic study on the influence of MWD shape on the physical properties of HDPE. Through rheological testing, we observe a difference in complex viscosity and shear thinning with opposite MWD skew. However, tensile testing reveals that the MWD skew does not impact the strain at break, signifying the ability to influence HDPE processing without compromising material strength.
RESUMEN
Design and synthesis of a Ni(ii) "sandwich" α-diimine complex (1) resulted in a switchable catalyst for the living polymerisation of ethylene over a range of temperatures and pressures. Varying these conditions produced a well-defined tetrablock copolymer comprising branched and highly linear polyethylenes. This copolymer improved the toughness of a phase separated LDPE/HDPE blend by nonreactive interfacial compatibilisation.