Search results for "Polymer blend"

Photooxidative behaviour of polyethylene/polyamide-6 blends

2010

International audience; The photochemical behaviour of several polyethylene/polyamide-6 blends was studied under conditions of artificial accelerated weathering. Particular attention was paid to five different compositions ranging from pure polyethylene to pure polyamide with blends of PE/PA-6 of various compositions: 75/25, 50/50 and 25/75 wt/wt%. Analysis by infrared spectroscopy of the chemical modifications caused by photooxidation showed that exposing the polyethylene/polyamide-6 blends to UV-light irradiation led to the formation of oxidation photoproducts in both polymer phases. In agreement with both the mechanical and spectroscopic analyses, the photooxidation rate of the blends wa…

Tissue engineered vascular grafts based on poly-lactic acid blends

2013

A great deal of research has been pursued in the last decade with the goal of developing blood vessel substitutes. Tissue engineering has emerged as a promising approach to address the shortcomings of current options. One of the major tasks in this research field is the possibility to tune the biodegradability of the implantable devices (scaffolds). After implantation, the scaffold has to be replaced by extra cellular matrix; with this respect, it is crucial that this replacement takes place with appropriate dynamics and a well-defined timescale. In this work tissue-engineered vascular graft were produced, utilizing several PLLA/PLA blends (100/0, 90/10, 75/25 wt/wt) in order to tune their …

Reprocessing of polyethyleneterephthalate and characterisation of monopolymer blends of virgin and recycled polymers

1997

Recycling of polyethyleneterephthalate (PET from bottles is considered by changing both reprocessing machines and the effect of humidity. The rheological and mechanical properties of this recycled material remain very close to that of the virgin material provided that a careful drying is carried out before any melt operation. The reprocessing has been carried out mainly in view of the use of this secondary material in blends with virgin PET-monopolymer or homopolymer blends. Indeed, this use is a common industrial practice to reuse plastic scraps. Most monopolymer blends show properties between those of the two components but in some cases lower than those expected on the basis of an additi…

Nanofilled Thermoplastic-Thermoplastic Polymer Blends

2014

Poly lactic acid based foams prepared via thermally induced phase separation (TIPS): A method to tune the crystallinity

2012

Blends of Poly-L-Lactic Acid (PLLA) with two Poly-Lactic Acid (PLA) in different proportions (90/10 and 70/30) were utilized in order to produce biodegradable and biocompatible scaffolds for soft tissue engineering applications. The scaffolds were produced via thermally induced phase separation (TIPS) starting from ternary systems where dioxane was the solvent and water the non-solvent. Morphology was evaluated by Scanning Electron Microscopy (average pore size and interconnection). Moreover a DSC analysis was carried out on the as-obtained scaffold in order to obtain information about theirs thermal properties (enthalpy of melt and crystallization). The results showed that is possible to p…

Comparison of the solidification of a commercial PBT-PET blend with the behaviour of the constituents

2009

Phase separation of flowing polymer solutions

2008

Monte Carlo studies of polymer interdiffusion and spinodal decomposition: A review

1991

Abstract Putting a layer of polymer A on top of a layer of polymer B, the broadening of the interfacial profile is observed in the framework of a lattice model (‘bond fluctuation method’). The interdiffusion constant is studied as a function of chain length, vacancy concentration, and interaction energy between unlike monomers, and a comparison with pertinent theoretical predictions is made. A lattice model where polymers are represented as self-avoiding walks on a simple cubic lattice is used to model ‘spinodal decomposition’, i.e. phase separation by ‘uphill diffusion’ in the unstable part of the phase diagram of a polymer mixture. For chain lengths N ≤ 32, the linearized Cahn-like theory…

Combined SANS and SAXS experiments in polyolefins-hydrogenated oligocyclopentadiene (HOCP) blends

1998

Abstract Lamellar morphology in semicrystyalline polymer blends (iPP/HOCP and HDPE/HOCP) is investigated by means of Small Angle X-ray Scattering (SAXS) and Small Angle Neutron Scattering (SANS). The investigated blends present a complex phase diagram, as they show a miscibility gap. SAXS scattering curves of blends lying outside the miscibility gap can be analysed in the frame of the psuedo two phase model. In order to describe the complex morphology of blends lying inside the miscibility gap, the SANS technique revealed necessary. In this paper a novel method to describe the morphology of these complex systems by means of SANS is presented.

Monte Carlo simulation of polymers at interfaces

1993

Abstract Polymers at interfaces pose challenging problems to statistical physics because their configurations often differ greatly from the bulk. Computer simulation of coarse-grained models then gives valuable insight and allows stringent tests of various theoretical predictions. Three examples are briefly treated: chain configurations of B-chains in the surface-enriched B-rich layer of an (AB) binary polymer mixture; “frustrated” lamellar ordering in ultra-thin block-copolymer films; and the collapse of polymer brushes in bad solvents.