Search results for " blends"

PREPARATION AND CHARACTERIZATION OF CLAY NANOCOMPOSITES BASED ON COMPATIBILIZED POLYAMMIDE6/POLYETHYLENE BLENDS

2008

Photo-oxidation behaviour of polyethylene/polyamide 6 blends filled with organomodified clay: Improvement of the photo-resistance through morphology …

2010

Abstract The impact of small amounts of organomodified clay (OMMT) on the photo-degradation behaviour of two blends obtained by mixing either low-density polyethylene (LDPE) or high density polyethylene (HDPE) with polyamide 6 (PA6) (LDPE/PA6 and HDPE/PA6 75/25 wt-%) was studied. The complex photo-degradation behaviour was followed by monitoring the main physical–mechanical properties of the blends. In particular, mechanical and spectroscopic tests were performed in conditions of accelerated artificial aging. An accurate mechanical and morphological characterization was previously carried out. The presence of the OMMT promotes the unexpected formation of a co-continuous morphology for the H…

Low-density polyethylene/polyamide/clay blend nanocomposites: Effect of morphology of clay on their photooxidation resistance

2017

The photooxidation behaviour of low-density polyethylene (LDPE)/polyamide (PA) blends, containing polyamide 11 (PA11) or polyamide 6 (PA6), has been investigated in the absence and presence of a small amount of commercial organomodified clay (OMMT). The polymer blends LDPE/PA11 and LDPE/PA6 at 75/25 wt./wt.%, with and without OMMT, have been prepared by a two-step procedure: extrusion and sheet formulation. The formulated complex systems have been subjected to accurate morphological analysis in order to evaluate the effect of the OMMT presence on the refinement of the blend morphology. Furthermore, the produced sheets have been subjected to arterial UVB exposure and the variations of the me…

Modification of EVOH copolymers with e-caprolactone: synthesis and compatibilization effects in PE/PVC blends

2001

Polyethylene-polycaprolactone graft copolymers with different chemical structures (i.e. different number and length of PCL grafts and molecular weight of PE backbone) were synthesized from various EVOH copolymers and e-caprolactone, using Aluminum isopropoxide as catalyst, and were tested for their compatibilizing capability in PE/PVC blends. PE and PCL segments in the graft copolymers were found completely immiscible, while PCL segments of the graft copolymers were found completely miscible with PVC. When graft copolymers were added to PE/PVC blends they proved to be good agents for the dispersion of PVC phase in the PE matrix. SEM showed also improved adhesion between the dispersed PVC ph…

UNEVEN DISTRIBUTION OF ORGANOCLAY IN HDPE/PA6 BLENDS - IMPACT OF MICROSTRUCTURE AND MECHANICAL BEHAVIOUR

2009

Oxazoline functionalization of polyethylenes and their blends with polyamides and polyesters

2001

The compatibilization of blends of polyamide-6 (PA6) with linear low density polyethylene (LLDPE) and of poly(ethylene terephthalate) (PET) with high density polyethylene (HDPE), by functionalization of the polyethylenes with oxazoline groups was investigated. Chemical modification of LLDPE and HDPE was carried out by melt free radical grafting with ricinoloxazoline maleinate. Blends preparation was made either with a two-steps procedure comprising functionalization and blending, and in a single step in which the chemical modification of polyethylene with the oxazoline monomer was realized in situ, during blending. The characterization of the products was carried out by FTIR spectroscopy an…

Effect of adding new phosphazene compounds to poly(butylene terephthalate)/polyamide blends. I: Preliminary study in a batch mixer

2005

Abstract Poly(butylene terephthalate) (PBT) and a sample of polyamide have been melt processed in the presence of two new phosphazene compounds, namely 2,2-dichloro-4,4,6,6-bis[spiro(2′,2″dioxy-1′,1″biphenyl)]cyclotriphosphazene (2Cl-CP) and 2,2-bis-(2-methoxy-4-methyleneoxy-phenoxy)-4,4,6,6,-bis[spiro(2′,2″dioxy-1′,1″biphenyl)]cyclophosphazene (CP-2EPOX). The blends were prepared by using polyamide 6 (PA6) at 25/75 w/w and 75/25 w/w composition. In order to perform a preliminary analysis on the behaviour of the blends, the materials were prepared in a batch mixer. The materials have been completely characterized from a rheological, morphological, mechanical point of view. The results indic…

Synthesis of PP-LCP graft copolymers and their compatibilizing activity for PP/LCP blends

1998

The aim of this work was the synthesis of new graft copolymers consisting of polypropylene (PP) backbones and liquid crystalline polymer (LCP) branches, to be used as compatibilizing agents for PP/LCP blends. The PP-g-LCP copolymers have been prepared by polycondensation of the monomers of a semiflexible liquid crystalline polyester (SBH 1 : 1 : 2), that is, sebacic acid (S), 4,4′-dihydroxybiphenyl (B), and 4-hydroxybenzoic acid (H) in the mole ratio of 1 : 1 : 2, carried out in the presence of appropriate amounts of a commercial acrylic-acid-functionalized polypropylene (PPAA). The polycondensation products, referred to as COPP50 and COPP70, having a calculated PPAA concentration of 50 and…

Effectiveness of organoclays as compatibilizers for multiphase polymer blends - A sustainable route for the mechanical recycling of co-mingled plasti…

2014

We prepare and characterize multiphase systems in which small amounts of recycled polymer, namely polyethylene terephtalate (PET) ground from waste bottles, are dispersed in a co-continuous blend of high-density polyethylene (HDPE) and polypropylene (PP). Some of such ternary systems are also filled with plate-like clay nanoparticles with different polarities, in order to assess their influence on the morphology and mechanical behaviour of the blends. On the basis of preliminary wettability considerations and inspections by means of scanning electron microscopy (SEM), the PET is found to preferentially locate within the PP phase. Such a positioning is desirable in order to minimize the pres…

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 …