Search results for "Polyolefin"

Oxazoline-containing compatibilizers for polyamide/SAN and polyamide/ABS blends

2002

Polyamide (PA) and acrylonitrile/butadiene/styrene copolymer (ABS) may appear as a mixture in the recycled plastic stream. The incompatibility of these blends results in a blend with poor mechanical properties. The aim of this work is to partially convert the nitrile groups of the acrylonitrile/styrene copolymer (SAN) into oxazoline groups by reaction with aminoethanol (AE). Such modified SAN (SAN-m) can react with the amine or carboxylic acid end groups of PA, and therefore used as compatibilizers for blends of PA with ABS. SAN-m was found to reduce the SAN-domain size in the PA/SAN-blends. The initial acrylonitrile content of SAN-m had a strong influence on the degree of conversion into o…

Preparation and Characterization of Polyolefin-Based Nanocomposite Blown Films for Agricultural Applications

2009

These kinds of filmshave,asaprimaryaim,tocreateafavorablemicro-climateto accelerate the plant growth.Thematerialsfortheseapplicationsmustpossessseveralspecificandpeculiarcharacteristics,suchastheabilitytobeshaped into films (even with wide dimensions and largethickness ranges), good deformability and tear resistancetogetherwithasufficientrigidity,transparencyforUVandIR radiation in particular regions of the spectrum, a goodresistance to photo-oxidative phenomena and for someapplications to provide a barrier for certain gases.Moreover, an important property requested for thematerials used for greenhouse covering is the capabilityto diffuse the light. In fact, according to some studies,diffused l…

Melt stabilisation of high-density film-grade polyethylene

2001

The thermoxidative degradation of a high-density polyethylene stabilised either with standard and novel kinds of antioxidants was examined at many different temperatures. The aim of this work was to investigate the degradation response (crosslinking or chain-breakage) on the polyolefin molecular structure in terms of low shear rate melt viscosity increment and oxidation induction time both studied through steady and dynamic shear flow tests performed in a rotational rheometer. Lactone type antioxidants, especially the one containing P-EPQ phosphite component, exhibit the lowest thermoxidative degradation at high temperatures. Vitamine E, used in blend with a phosphite, appears to be a good …

Olefin polymerization and copolymerization by complexes bearing [ONNO]-Type salan ligands: Effect of ligand structure and metal type (titanium, zirco…

2014

A series of novel titanium(IV) complexes bearing tetradentate [ONNO] salan type ligands: [Ti{2,2′-(OC6H3-5-t-Bu)2-NHRNH}Cl2] (Lig1TiCl2: R = C2H4; Lig2TiCl2: R = C4H8; Lig3TiCl2: R = C6H12) and [Ti{2,2′-(OC6H2-3,5-di-t-Bu)2-NHC6H12NH}Cl2] (Lig4TiCl2) were synthesized and used in the (co)polymerization of olefins. Vanadium and zirconium complexes: [M{2,2′-(OC6H3-3,5-di-t-Bu)2-NHC6H12NH}Cl2] (Lig4VCl2: M = V; Lig4ZrCl2: M = Zr) were also synthesized for comparative investigations. All the complexes turned out active in 1-octene polymerization after activation by MAO and/or Al(i-Bu)3/[Ph3C][B(C6F5)4]. The catalytic performance of titanium complexes was strictly dependent on their structures an…

Recycling of inside upholstery of end-of-life cars

2005

A model study for the recycling of the interior upholstery plastic parts of end-of-life cars has been carried out by reprocessing the homogenized scraps of an upholstery farm in the presence of different compatibilizer precursors, such as an ethylene-glycidylmethacrylate copolymer (EGMA), a maleic anhydride functionalized thermoplastic elastomer (SEBS-MA), etc. The investigated scraps contained recycled polyethylene (from agricultural uses) and poly(ethylene terephthalate), as the main components, plus minor proportions of polypropylene, polyamide-6, and other additives, including an ethylene copolymer (EC), probably an ethylene-acrylic acid copolymer, which is used to compatibilize the car…

Study of thermal properties of polyethylene and polypropylene nanocomposites with long alkyl chain-substituted POSS fillers

2016

The effect of incorporation of octakis({alkyl}dimethylsiloxy)octasilsesquioxanes molecules with n-octyl, n-octadecyl and 4-methyl-hexyl substituents on thermal properties of polypropylene (PP), low-density polyethylene (LDPE) and high-density polyethylene (HDPE) was investigated. Thermal properties of those composite materials were evaluated by means of the differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) methods. The type and mass% content of POSS nanofillers influenced the crystallization and melting properties as well as thermal stability of the obtained polyolefin nanocomposites. The incorporated POSS particles—acting as nucleating agents—improved the crystall…

On the mechanism of compatibilization of polyolefin/liquid crystalline polymer blends with graft copolymers

2000

The compatibilization mechanism of some compatibilizers for blends of polyolefins with a liquid crystalline polymer (LCP) was studied. Polyethylene (PE) and polypropylene (PP) were blended with a semirigid LCP (SBH) in a batch mixer, either with and without compatibilizers. The latter were two commercially available samples of functionalized polyolefins, that is, a PE-g-MA (HDM) and a PP-g-AA (Polybond 1001) copolymer and some purposely synthesized PE-g-LCP and PP-g-LCP copolymers. Microtomed films of the binary and the ternary blends were annealed at 240°C on the hot stage of a polarizing microscope and the changes undergone by their morphology were recorded as a function of time. The resu…

Oxovanadium(IV) complexes with [ONNO]-chelating ligands as catalysts for ethylene homo- and copolymerization

2014

Oxovanadium(IV) complexes with (ONNO)-type tetradentate Schiff base ligands: salen, acacen, aceten, acetph (H2salen = N,N'-ethylenebis(salicylideneimine), H2aceten = N,N'-ethylenebis(2-hydroxyacetophenoneimine), H2acacen = N,N'-ethylenebis(acetylacetonimine), H 2 acetph = N ,N ' -phenylene-1,2-b is (2-hydroxyacetophenoneimine)), were the first time investi- gated in ethylene polymerization and ethylene/1-octene copo- lymerization processes. In general, all these complexes are moderately active precatalyst for ethylene polymerization up- on activation with EtAlCl2 and they give high molecular weight linear polyethylenes. Their activity in copolymeriza- tion was found relatively low. However,…

Influence of the matrix on photo-oxidative degradation of polyolefin based nanocomposite films

2008

Effect of Different Matrices and Nanofillers on the Rheological Behavior of Polymer-Clay Nanocomposites

2010

In this work, a comprehensive study of the rheologi-cal behavior under shear and isothermal and nonisothermal elongational flow of low density polyethylene (LDPE) and ethylene-vinyl acetate copolymer (EVA) based nanocomposites was reported to evaluate their "filmability", that is, the ability of these material to be processed for film forming applications. The influence of two different kinds of organoclay - namely Cloisite 15A and Cloisite 30B - and their concentration was evaluated. The presence of filler clearly affects the rheological behavior in oscil-latory state of polyolefin-based nanocomposites but the increase of complex viscosity and the shear thinning are not dramatic. A larger …