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Amine Light Stabilizers (amine + light_stabilizer)

Distribution by Scientific Domains

Polymers and Materials Science	80%

Kinds of Amine Light Stabilizers

hindered amine light stabilizer

Selected Abstracts

Facile synthetic route to polymerizable hindered amine light stabilizers for transition-metal-catalyzed olefin copolymerization

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2004
M. Auer
Abstract This work describes a facile method by which a polymerizable hindered amine light stabilizer, 4-(10-undecylidene)-2,2,6,6-tetramethylpiperidine, was prepared in a single-step procedure by means of a Wittig reaction. The monomer was successfully copolymerized with ethylene with a rac -[dimethylsilylenebis(4,5,6,7-tetrahydro-1-indenyl)]zirconium dichloride/methylalumoxane catalyst system. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1350,1355, 2004 [source]

Quantitative analysis of an oligomeric hindered amine light stabilizer in polypropylene by matrix-assisted laser desorption/ionization mass spectrometry using a solid sampling technique

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2006
Yoshihiko Taguchi
A small amount of an oligomeric hindered amine light stabilizer (HALS) (Adekastab LA-68LD) in polypropylene (PP) materials was directly determined by solid sampling matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) using an internal standard method. First the matrix reagent (dithranol), 20,mg, and the empirically selected internal standard, angiotensin I (MW,=,1296.5), 5,µg, were premixed in the solid state. The matrix mixture was then co-ground with the PP sample containing the HALS in liquid nitrogen using a freezer mill. The powdered sample mixture was spotted on the sample plate, suspended in ion-exchanged water, dried to adhere on the plate, and subjected to MALDI-MS. Three series of the HALS components accompanied by the oxidized species were clearly observed as their molecular ions (M.+) along with that of the internal standard in the mass spectra. A fairly good linear relationship (R2,=,0.9991) with a relative standard deviation of ca. 11% was observed between the relative peak intensities of the HALS components and the HALS contents ranging from 0.1,2.5,wt%, which could be used as the calibration line to determine the HALS content in PP composites directly by MALDI-MS. The UV-exposed PP composite samples were evaluated by this method to interpret the photostabilizing action of HALS in the PP materials based on the observed change in the relative abundances of the original and oxidized HALS components as a function of UV-exposure time. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Photostability of isotactic polypropylene containing monoazo pigment

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008
Zahra Ahmadi
Abstract The photodegradation of isotactic polypropylene (PP) films containing a monoazo pigment and hindered amine light stabilizers (HALS) has been undertaken. PP films were exposed to medium pressure mercury lamp radiation in the laboratory for periods of up to 8 weeks and the degree of degradation (oxidation/deterioration) was examined using FTIR spectroscopy and differential scanning calorimetry (DSC) as well as by measuring changes in the mechanical properties, contact angle, and density. The results of these measurements indicate that unstabilized PP films degraded after only 240-h irradiation. By adding an organic pigment to PP films along with antioxidant and HALS, the photostability of PP films increased to the 1500-h level. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source]

Facile synthetic route to polymerizable hindered amine light stabilizers for transition-metal-catalyzed olefin copolymerization

Synergistic profiles of chain-breaking antioxidants with phosphites and hindered amine light stabilizers in styrene,ethylene,butadiene,styrene (SEBS) block copolymer

JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2006
Cristina Luengo
The photostabilization of poly(styrene- b -ethylene- co -butylene- b -styrene) (SEBS) by phosphite/p -hydroxybenzoate antioxidants and hindered phenol/hindered amine light stabilizers (HALS) was studied by using a variety of spectroscopic methods, including FTIR, UV, and luminescence spectroscopy coupled with crosslinking and hydroperoxide analysis. The results were compared with those obtained for hindered phenols and their combinations with phosphite antioxidants. All the stabilizing packages stabilized the SEBS in terms of the inhibition of discoloration and the formation of hydroperoxides, acetophenone, and oxidation products, as well as chain scission and disaggregation of the styrene units. Although phosphite/p -hydroxybenzoate combinations appeared to reduce the formation of oxidation products, they did not show any remarkable enhancement in long-term stabilization with respect to phenolic/phosphite antioxidants. On the other hand, strong synergistic profiles were found with the HALS. Mobility and diffusion impediments in the polymeric material appeared to play an important role in the stabilizing activity of the HALS. J. VINYL. ADDIT. TECHNOL. 12:8,13, 2006. © 2006 Society of Plastics Engineers [source]

Effect of hindered piperidine light stabilizer molecular structure and UV absorber addition on the oxidation of HDPE.

JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 4 2004
Part 2: Mechanistic aspects, electron spin resonance spectroscopy study, molecular modeling
The first in this series of papers explored the effect of the structural characteristics of 2,2,6,6-tetramethylpiperidine-based hindered amine light stabilizers (HALS) on the thermal and photostabilization of high-density polyethylene. In the second part, the energies (stabilities) of the nitroxyl radicals and various intermediate species have been predicted using AccuModel® and related to stabilization performance and electron spin resonance (ESR) spectral data. Nitroxyl radicals with low predicted stability generally afforded improved thermal and photostabilization. ESR spectra were used to obtain values of nitroxyl radical concentration ([>NO·]) and g -factor as a function of pre-aging time for combinations of pre-aged HDPE and >NH HALS. Demethylation reactions of > N-methyl HALS resulted in uselessly weak ESR spectra. The HALS that afforded poor thermal oxidative stabilization gave rise to pronounced minima in [>NO·] that coincided with a maximum in hydroperoxide concentration. The g -factor values indicated that a predominant nitroxyl canonical form generally promoted superior thermal oxidative stabilization, whereas a predominance of the dipolar N·+O, form promoted superior photo-oxidative stabilization. These trends may be related to greater radical-scavenging and peroxide-trapping effects, respectively. Molecular modeling and ESR spectra can therefore provide valuable insight into the effectiveness of HALS and stabilization mechanisms. J. Vinyl Addit. Technol. 10:159,167, 2004. © 2004 Society of Plastics Engineers. [source]

Effect of hindered piperidine light stabilizer molecular structure and UV-absorber addition on the oxidation of HDPE.

JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2004
Part 1: Long-term thermal, photo-oxidation studies
This series of papers explores the effect of structural characteristics of 2,2,6,6-tetramethylpiperidine-based hindered amine light stabilizers (HALS) on the long-term (40 months) thermal (110°C in air) and photo-stabilization (Microscal unit wavelength >300 nm) performance characteristics of high-density polyethylene formulations. Possible synergism with a triazine functional UV absorber is also explored. Under thermal degradation (measured by carbonyl index) the polymeric HALS performed best, mainly because of reduced volatilization. Additionally, >N-methyl HALS generally showed superior performance under thermal degradation. There was no synergism between an N-CH3 polymeric HALS and the UV1164 triazine additive. However, the equivalent N-H polymeric HALS interacted in a complex manner with UV1164, giving synergism and antagonism, depending on HALS/UV1164 ratio. Strong synergism was evident with the monomeric HALS when the total stabilizer level was 0.2% w/w. Reduction in the overall stabilizer level to 0.05% w/w eliminated the synergism. The UV1164 alone led to rapid and intense yellowing; however, the rate and intensity of yellowing reduced dramatically upon combination with HALS, particularly when the UV1164 level was above 0.1% w/w. When the formulation was under UV attack, the molar mass and the type of N-substitution had no influence on stabilization performance because of the relatively low temperature of testing (leading to reduced volatilization), and the similarly effective UV-stabilization routes for N-methyl HALS and N-H HALS. Under UV attack, yellowing reached a maximum and then decreased to approximately the initial level, while HALS/UV1164 combinations generally showed weak antagonism. J. Vinyl Addit. Technol. 10:79,87, 2004. © 2004 Society of Plastics Engineers. [source]

Factors influencing the adsorption of stabilizers onto carbon black: Flow microcalorimetry studies

JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 2 2000
J. M. Peñta
The surface activity of various kinds of carbon black toward phenolic antioxidants and hindered amine light stabilizers (HALS) was examined by using flow microcalorimetry (FMC). Phenolic hydroxyl and ester groups were found to be the moieties responsible for the adsorption activity of primary phenolic antioxidants onto the carbon black surfaces. Furthermore, a difference in the degree of phenolic hydroxyl hindrance by alkyl groups was found to be the main factor affecting the adsorption activity of the phenol group. A difference in the degree of substitution of the piperidine amine, as well as the number and type of functionality per molecule, are important factors that were found to influence the adsorption activity of HALS. Data from adsorption studies using model compounds, some of which represented functional portions of the stabilizer molecules, reflected behavior sin ilar to that observed with the stabilizers. In addition, these latter results showed that FMC analysis can yield potentially useful information beyond that given by the usual parameters such as BET surface area, I2, DBP, and CTAB adsorption values. Differences in the behavior between types of carbon black were evident and showed that the specific surface area is not the most important factor in the adsorption/desorption activity, but also the chemical nature of the surface. From the activity observed for model compounds, it was deduced that the presence of secondary and tertiary amine in the backbone and branch structures also has an important role in the adsorption activity of polymeric HALS. In general, the observed quantities can be related to the values of adsorption/desorption energy and to the molar mass of the probe. [source]