Michele Edge

Some of the most important commercial near UV photoinitiators have been analyzed by UV spectroscopy to evaluate the type of electronic transitions occurring upon absorption of light. Photocuring studies have been undertaken by real time infrared spectroscopy (RTIR) in clear and pigmented (black, magenta, cyan, and yellow) systems with UV and visible light at different photoinitiator concentrations in the presence

In a previous paper it was demonstrated for the first time, that carbon black pigments have the ability to operate as effective singlet and triplet quenchers. This work was undertaken directly in the polymer using the inherent long-lived luminescent species as triplet donor species. In order to ascertain the effectiveness of the quenching mechanism and its inter-relationship with carbon black

Abstract 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 ...

Abstract The photostabilization of poly (styrene-b-ethylene-co-butylene-b-styrene)(SEBS), by hindered phenols and their combination with phosphite antioxidants has been studied by using a variety of spectroscopic methods including FTIR, UV, and luminescence ...

The first and second part of this series of papers investigated the interaction between carbon black and stabilisers (phenolic antioxidants and HALS, respectively) and showed that the mechanism was dependent on both the chemical nature of the carbon black surface and the molecular structure of stabilisers. In this third part, the interactions between model compounds, of varying acidity, and the same four carbon blacks, are investigated using flow micro-calorimetry (FMC) and Fourier transform Infrared spectroscopy (FTIR). As with the first and second parts, differences in adsorption behaviour between the four types of carbon black were evident and were principally related to the chemical nature of the surfaces and the adsorbates. In this study further insight in to the nature of the interactions between the carbon black surface functional groups and the acidic and basic probes has been acquired. The main forms of interaction are hydrogen bonding and Lewis and Bronsted acid/base inter...

The interactions between two commercial hindered piperidine compounds, three commercial antioxidants, a secondary antioxidant and two types of furnace carbon blacks (with a different surface area and surface chemistry) in the thermal oxidation of LDPE have been studied using the oxidation induction time test. During thermal degradation the interactions were variable, being both antagonistic and synergistic. Generally, for the primary

Previous work concerning the overall adsorption activity of different stabilisers [primary and secondary antioxidants and hindered amine light stabilisers (HALS) [Peña, JM, Allen, NS, Edge, M, Liauw, CM. Factors influencing the adsorption of stabilisers onto carbon black: flow microcalorimetry studies J Vinyl Add Technol, 2000;6:62–68] [1] onto carbon black has allowed an understanding of the concentration of stabilisers adsorbed after

The radical content and its change under thermal treatment of different types of carbon black (CBs) are examined using electron spin resonance (ESR) through calibration via stable free radicals. In order to characterise a range of different CBs, Fourier transform infrared ...

The thermal and photo-oxidative stabilisation of high styrene–butadiene copolymer (SBC) with high styrene content (K-Resin) has been studied using a variety of analytical and spectroscopic methods including yellowness, luminescence and FT-IR spectroscopy coupled with hydroperoxide analysis in order to understand the nature and effectiveness of the processes involved. The next stage of the program was to evaluate the effects of

The photo-oxidative degradation of poly[styrene-b-ethylene-co-butylene-b-styrene], SEBS, has been studied at wavelengths cut-off below 290nm, and monochromatic light of 254nm and 365nm, using a variety of spectroscopic methods including FTIR, UV and luminescence spectroscopy coupled with crosslinking and hydroperoxide analyses in order to understand the mechanisms involved. A study on polystyrene photodegradation is also compared at varying wavelengths in order to

The interaction between two commercial hindered piperidine compounds, three commercial antioxidants, a secondary antioxidant and two types of furnace carbon black (CB) (with a different surface area and surface chemistry) in the photo-oxidation of LDPE film have been studied using FTIR infrared spectroscopy. The nature of stabiliser-CB interactions has also been analysed through the use of flow microcalorimetry. The stabilisers used are, a commercial polymeric HALS, namely Chimassorb 944®, and Tinuvin 622® LD®, primary and secondary antioxidants, namely Irganox 1010® and Irganox 1076®, Cyanox 1790® and Irgafos 168®. For the fillers, two carbon blacks were chosen with different features as the specific surface particle size and chemistry. During photo-oxidation the interactions are variable, being both antagonistic and synergistic. Generally for the primary antioxidants alone their photostabilising effects on the polymer film are low or negligible and can be related to the stability of the additives. However, in the presence of a hindered piperidine light stabiliser no such correlations between polymer and antioxidant stability exist. In most of the cases, antagonistic interactions were found between HALS and the antioxidants. Differences in the performance of the polymeric type of HALS were evidenced, as well as between the CB grades. Less antagonism was found between primary and secondary antioxidants with CB for two-additive formulations. This effect is overcome by a powerful synergistic interaction in three additive formulations. Antagonism was found between one HALS and CB. It is concluded that the nature of the CB plays an important role in controlling their performances as a stabilising agent alone, as well as their interactions with light stabilisers and antioxidants.

The surface activity of different types of carbon black with secondary antioxidants (aryl phosphites and phosphonites) is examined using flow micro-calorimetry (FMC), X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red spectroscopy (FTIR). Significant differences in both the overall adsorption activity and the levels of probe adsorption are observed. Differences in behaviour between types of carbon black are evident and show

The photoinduced polymerization activities of seven novel phenylthio substituted benzophenones have been determined and compared to that of benzophenone itself in different monomers and prepolymers using real time infra-red (RTi.r.) and pencil hardness methods. Four novel ...