Search results for "Branching"

Molecular modifications—Mechanical behaviour relationships for gamma irradiated LLDPE/PA6 blends

1994

Abstract The molecular modifications, due to γ radiation under vacuum, of linear low density polyethylene/polyamide 6 blends are presented and related to their mechanical behaviour. Solubility and melt viscosity tests indicate that in blends the polyethylene component undergoes mainly crosslinking phenomena, whereas the main effect on polyamide is chain branching. According to these molecular modifications, the most relevant effect is the increase of the tensile modulus for the polyethylene rich blends and the increase of the impact strength for the polyamide rich blends.

Ferrocenyl-functionalized long chain branched polydienes

2009

A convenient two-step approach for the synthesis of ferrocenyl-functionalized long chain branched polydienes, based on both butadiene and isoprene, respectively, is presented. Classical living anionic polymerization was used to synthesize different AB n type poly(diene) macromonomers with moderate molecular weights between 1700 and 3200 g/mol and narrow polydispersity. Quantitative end-capping with chlorodimethylsilane resulted in the desired AB n macromonomer structures. In the ensuing Pt-catalyzed hydrosilylation polyaddition, branched, functionalized polydienes were obtained by a concurrent AB n + AR type of copolymerization with mono-and difunctional ferrocenyl silanes (fcSiMe 2 H or fc…

Synthesis of reactive hyperbranched and star-like polyethers and their use for toughening of vinylester–urethane hybrid resins

2004

A vinylester – urethane hybrid resin (VEUH) was toughened by adding various vinyl-functionalized branched polyethers in 10 and 20 wt%. Two sets of hyperbranched polymers (HBPs) with different branching density were compared with a set of six-arm star polymers. Besides the architecture, the polymers also varied in their characteristics (molecular mass and mass distribution, vinyl/hydroxy ratio). The morphology of the modified VEUH was studied by dynamic-mechanical thermal analysis (DMTA), transmission (TEM) and scanning electron microscopy (SEM). The toughness was characterized by the fracture energy ðGcÞ determined on compact tension specimens at room temperature. It was established that th…

Üuber die kationische polymerisation von äthylensulfid, initiiert durch SO3

1971

SO3 verursacht eine heftige Polymerisation von Athylensulfid in wasserfreien, inerten organischen Losungsmitteln. Die kinetischen Daten, die chemische Analyse der Endgruppen und die IR-spektroskopische Untersuchung des Polymerisats sprechen gegen eine Cokatalyse und fur einen direkten zwitterionischen Initiierungsschritt unter Bildung von Die kationischen aktiven Zentren werden rasch durch Reaktion mit den Sulfidgruppen des Oligomeren unter Bildung nicht wachstumsfahiger, acyclischer Sulfoniumionen desaktiviert; dadurch bleiben die kinetischen Kettenlangen klein, und es entsteht ein verzweigtes oder vernetztes, unlosliches Produkt. SO3 is a vigorous initiator of the cationic polymerization …

1983

Water soluble polyamides with iminoethylene and oxyethylene units in the main chain were obtained by condensation polymerization of diethylenetriamine and triethylenetetramine with suitable dimethylesters containing two or three oxyethylene units. The molecular weights were in the range of Mn = 5000–7000. By potentiometric and conductometric titration only 80–85% of the expected amount of basic groups was found which was probably caused by branching. Durch Polykondensation von Diethylentriamin und Triethylentetramin mit Dimethylestern von Sauren, die zwei oder drei Oxyethyleneinheiten enthalten, wurden wasserlosliche Polyamide mit Iminoethylen- und Oxyethyleneinheiten in der Hauptkette erha…

Influence of long chain branching on the elongational behaviour of different polyethylenes and their blends

1986

Elongational data on a series of polyethylenes with different structure and on their blends are presented in order to correlate the extensional behaviour with the long chain branching degree.

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.

Chimney and Periscope Grafts: Mid-term Results in 77 Consecutive Patients with Complex Aortic Aneurysms

2012

Not applicable

Measurements of the top quark branching ratios into channels with leptons and quarks with the ATLAS detector

2015

Measurements of the branching ratios of top quark decays into leptons and jets using events with t[bar over t] (top antitop) pairs are reported. Events were recorded with the ATLAS detector at the LHC in pp collisions at a center-of-mass energy of 7 TeV. The collected data sample corresponds to an integrated luminosity of 4.6  fb[superscript −1]. The measured top quark branching ratios agree with the Standard Model predictions within the measurement uncertainties of a few percent.

Experimental study of $^{100}$Tc $\beta$ decay with total absorption $\gamma$-ray spectroscopy

2017

International audience; The β decay of Tc100 has been studied by using the total absorption γ-ray spectroscopy technique at the Ion Guide Isotope Separator On-Line facility in Jyväskylä. In this work the new Decay Total Absorption γ-ray Spectrometer in coincidence with a cylindrical plastic β detector has been employed. The β intensity to the ground state obtained from the analysis is in good agreement with previous high-resolution measurements. However, differences in the feeding to the first-excited state as well as weak feeding to a new level at high excitation energy have been deduced from this experiment. Theoretical calculations performed in the quasiparticle random-phase approximatio…