Binary and ternary blends of high-density polyethylene with poly(ethylene terephthalate) and polystyrene based on recycled materials

Super-Robust Polylactide Barrier Films by Building Densely Oriented Lamellae Incorporated with Ductile in Situ Nanofibrils of Poly(butylene adipate-co-terephthalate)

Remarkable combination of excellent gas barrier performance, high strength, and toughness was realized in polylactide (PLA) composite films by constructing the supernetworks of oriented and pyknotic crystals with the assistance of ductile in situ nanofibrils of poly(butylene adipate-co-terephthalate) (PBAT). On the basis that the permeation of gas molecules through polymer materials with anisotropic structure would be more frustrated, we believe that oriented crystalline textures cooperating with inerratic amorphism can be favorable for the enhancement of gas barrier property. By taking full advantage of intensively elongational flow field, the dispersed phase of PBAT in situ forms into nanofibrils, and simultaneously sufficient row-nuclei for PLA are induced. After appropriate thermal treatment with the acceleration effect of PBAT on PLA crystallization, oriented lamellae of PLA tend to be more perfect in a preferential direction and constitute into a kind of network interconnecting with each other. At the same time, the molecular chains between lamellae tend to be more extended. This unique structure manifests superior ability in ameliorating the performance of PLA film. The oxygen permeability coefficient can be achieved as low as 2 × 10(-15) cm(3) cm cm(-2) s(-1) Pa(-1), combining with the high strength, modulus, and ductility (104.5 MPa, 3484 MPa, and 110.6%, respectively). The methodology proposed in this work presents an industrially scalable processing method to fabricate super-robust PLA barrier films. It would indeed push the usability of biopolymers forward, and certainly prompt wider application of biodegradable polymers in the fields of environmental protection such as food packaging, medical packaging, and biodegradable mulch.

Effects of SEBS-g-MA on Rheology, Morphology and Mechanical Properties of PET/HDPE Blends

The effects of additive styrene/ethylene-butylene/styrene copolymer grafted with maleic anhydride (SEBS-g-MA) were investigated on the rheology, morphology and mechanical properties of a polyethylene terephthalate (PET)/high density polyethylene (HDPE) blend. The ratio of the two components was changed in small increments to track phase inversion. The rheology measurements show that SEBS-g-MA acts differently on HDPE and PET, as different morphologies are formed due to viscosity ratio change. With the help of electron microscopy various phases after extrusion and after injection molding were revealed and identified. Because of the high viscosity of HDPE the co-continuous morphology was immediately formed when PET reached 30 vol%. The range of the co-continuous structure of the blend was wider when SEBS-g-MA was added, and the elongation at break also improved as additive content increased, without a significant strength decrease. The divergence of the mechanical properties from the theoretical value, i.e. the value determined by the mixing rule, can be explained by the changing phase structure.