Search results for "Ethylene"

Recycling of heterogeneous plastics wastes. II—The role of modifier agents

1993

Abstract Recycling of mixed plastics waste, mainly composed of PEs, PET and PVC has been carried out by blending with recycled polyethylene. Although the extrusion of these blends has been carried out at high temperatures, the degradation of the PVC was modest due to the short residence times. The mechanical properties of these secondary materials, up to about 30% of mixed plastics waste, are very similar to those of the recycled polyethylene, except for the elongation to break. By adding some modifier agents, the elongation at break and especially the impact strength can be further improved.

Positron Lifetime in Hostaphan

2006

Positron lifetime measurements in hostaphan RNK, used for encapsulation of Na positron sources, were performed. It was found that the parameter of positron lifetime spectra in hostaphan RNK differ markedly from those for other forms of polyethylene terephthalate. The maximum penetration depth of positrons from RNK hostaphan amounts 0.42 mm. The information gained in the present study is of great importance for experimenters using hostaphan RNK for encapsulation of positron sources.

Conformation of polyethylene molecules in the melt as revealed by small-angle neutron scattering

1975

Liquid Crystalline Copolyester Made from Recycled Polyethylene Terephthalate and p-Acetoxybenzoic Acid: Synthesis, Characterization and Blending with…

2013

Influence of molecular parameters on the elongational behaviour of different polyethylenes and their blends

1988

Elongational data on a large number of polyethylene samples with different structures and their blends are presented in order to evaluate the influence of the molecular weight and molecular weight distribution for a given degree of long chain branching. The elongational viscosity rises with the number of branch points and also with molecular weight and molecular weight distribution. Simple relationships between elongational viscosity at a given deformation and molecular parameters are presented.

Studies and Research on the Stress – Strain Analyses of the Polyethylene Pipe-Fitting Assemblies Accidentally Subjected to an External Force

2019

Abstract The paper aims at analyzing the behavior of the polyethylene pipe - fitting assembly in the case of accidental stress due to the accidentally occurring external forces (mechanized excavation in the assembly area). The study will identify the necessary computing relationships and the minimum value of the force to which the analyzed assembly breaks, as well as some solutions for avoiding these accidental stresses. A three-dimensional model of the assembly will be made by applying the external forces on three main directions, following the maximum stresses for the same value of the external force. Also, a welding of a polyethylene pipe-fitting assembly will be carried out and it will …

Thermodynamic theory of finite thickness of polyethylene crystals

1962

1991

Polyfunctional chloroformates were applied to the polymerization of 2-phenyl-2-oxazoline and 2-methyl-2-oxazoline. The use of a trifunctional initiator, viz. the chloroformate of 2,2-bis(hydroxymethyl)-1-butanol, led to three-arm star polymers of 2-oxazolines. Two macromolecular initiators, viz. poly(ethylene oxide) with two chloroformate end groups (α-chloroformyl-ω-chloroformyloxypoly(oxyethylene)) with number-average molar masses 350 g/mol ≤ Mn ≤ 6000 g/mol and α-chloroformyl-ω-methoxypoly(oxyethylene) with Mn = 350 and 750 g/mol were applied for the synthesis of poly(2-oxazoline)-block-poly(ethylene oxide)-block-poly(2-oxazoline) and poly(2-oxazoline)-block-poly(ethylene oxide) copolyme…

Beitrag zur hydroxymethylierung von hydroxyphenylenmethylen-verbindungen sowie IR- und UV-spektroskopische untersuchungen dieser verbindungen

1973

Es wurden hohermolekulare α-Brom- bzw. α-Methyl-ω-hydroxy[(2-hydroxy-5-methyl-1,3-phenylen)methylene] nach LEDERER und MANASSE dargestellt; die hochste erreichte rel. mol. Masse betrug rund 700. Mit steigender rel. mol. Masse wuchsen Zahl und Anteil der Nebenprodukte, so das die Reinigung bis zur dunnschichtchromatographischen Reinheit immer verlustreicher wurde und die Ausbeuten auf 10–15% abfielen. Einige der Nebenprodukte wurden isoliert; ihre Konstitution wurde aufgeklart und durch IR- und UV-Messungen bestatigt. Tetrasubstitutionsbanden, Methylengruppen- und Hydroxylgruppenbanden der IR-Spektren wurden eingehend untersucht. Die HUNTERsche Beziehung wurde bestatigt und ihre allgemeinere…

Polymere ester von Säuren des phosphors, 5. Ringöffnende polymerisation des 2-phenoxy-1,3,2-dioxaphospholan durch Michaelis-Arbuzov-reaktion

1977

2-Phenoxy-1,3,2-dioxaphospholane (14) was polymerized by benzyl halogenides at temperatures between 120 and 200°C. It was found that the main chain consists predominantly of unexpected ethylene 1,2-ethanediphosphonate units 7; only about 10% of the monomer was incorporated as the expected 2-hydroxyethanephosphonate structure. An insertion mechanism, proposed by Harwood and Patel for the analogous polymerization of 2-phenyl-1,3,2-dioxaphospholane, does not agree with our experimental results. A hypothesis is developed involving a two step addition process, which exclusively occurs at the chain end. Alternating, one monomer molecule is added by a normal Michaelis-Arbuzov-reaction, and then a …