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Bis(acetanilido)-tris(acetato)dicuprate(ii), [Cu2(C7H8N2O)2(CH3CO2−)3], is incorporated into MY721, a commercial epoxy resin recognised as an ‘industry standard’. Infrared spectroscopy and thermogravimetry are employed to examine the structure and thermal dissociation behaviour of the newly prepared complex. Multivariate analysis techniques (e.g.principal components analysis) are used to examine the spectral data to corroborate the dissociation temperature. The shelf life and cure characteristics of the commercial epoxy/curing agent formulation are determined using differential scanning calorimetry and vibrational spectroscopy.

A detailed study is presented of the high‐temperature cure of the difunctional monomer N‐(2‐biphenylenyl)‐4‐[2′‐phenylethynyl]phthalimide (BPP) and the thermal properties of the resulting homopolymer. Although the phenylethynyl groups are consumed within 1 h at 370 °C, other reactions continue well after this, leading to a cured polymer whose glass transition temperature (Tg) is highly dependent on cure time and temperature. A Tg of 450 °C is achieved after a 16 h cure at 400 °C. Use of chemometrics to analyse the infrared spectra of curing BPP provides evidence for changes in the aromatic moieties during cure, perhaps indicative of co‐reaction between the biphenylene and phenylethynyl groups; however, other processes also contribute to the overall complex cure mechanism. Despite the high Tg values, BPP homopolymer exhibits unacceptably poor thermo‐oxidative stability at 370 °C, showing a weight loss of about 50 % after 100 h ageing. This is perhaps a result of formation of degradatively unstable crosslink structures during elevated‐temperature cure. Copyright © 2004 Society of Chemical Industry

The vibrational spectra of norbornene (bicyclo[2,2,1]hept-2-ene) and nadic anhydride (cis-endo-5-norbornene-2,3-dicarboxylic anhydride) have been investigated by infrared, Raman and inelastic neutron scattering spectroscopies and density functional theory (DFT). For norbornene, the five missing fundamentals have been located. In the C–H stretch region, the infrared and Raman spectra synthesised from the DFT calculations are shown to be in poor agreement with the experimental spectra. Visualisation of the C–H stretch modes shows that assignments made on the basis of group frequency correlations are incorrect. Nadic anhydride has not been previously investigated by vibrational spectroscopy. This paper demonstrates that with state-of-the-art inelastic neutron scattering spectra it is possible to successfully analyse complex systems that have not been studied before.

A series of complexes incorporating diamine (o-phenylene diamine and 2-aminobenzylamine) ligands and containing the acetato and chloro salts of Ni(II) and Cu(II) was incorporated into two commercial epoxy resins recognized as industry standards (MY721 and MY750). The cure properties of the complexes are assessed alongside commercial curative systems. Thermal analysis (principally differential scanning calorimetry) shows that the nature of the cure mechanism can be dramatically affected by the nature of the transition metal and counterion (and the level of curing agent incorporation). For example, by using a nickel(II) acetato complex rather than its chloro analog, the onset of the cure reaction of MY721 may be reduced by 40 K. Thermogravimetric analysis, and visible, infrared, and electron spin resonance spectroscopy are employed to determine the point at which the complexes undergo dissociation. The data show that Cu(2-ABA)2(ac)2 appear to dissociate at temperatures between 70 and 80°C in octan-1-ol. A multivariate approach is applied to the analysis of infrared data obtained for solvated complex samples subjected to a heating program and the results are consistent with the dissociation temperature obtained from the other spectral data. The data suggest that the aromatic amino function in the complex undergoes dissociation from the metal at a lower temperature than the aliphatic amine. The 2-ABA-based complexes containing chloride counterions undergo gelation at higher temperatures than their acetato analogs (for both commercial epoxy systems). The newly prepared complexes generally display ηmin values comparable with the commercial curative systems [the exceptions being Cu(2-ABA)2Cl2 and Ni(OPD)3Cl2, which produce markedly higher values of 14 and 10 P, respectively], but it is believed that this is due to agglomeration and settling of the complex as the resin viscosity decreases during the heating cycle. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2411–2424, 2002

The ability to determine the molar mass of a polymer is of fundamental importance to describe polymer molecular characteristics. Conventional methods for measuring molar mass include viscometry, osmometry, light scattering and analytical gel permeation chromatography (GPC). Although high quality data can be obtained by these methods, the results can be significantly affected by sample preparation, and they are often time consuming and unsuitable for real‐time on‐line processing.In this paper, we demonstrate the potential of determining polymer molar mass using optical spectroscopy combined with chemometric analysis. This is technically attractive because optical spectroscopy is routinely used to collect process data on‐line and some refineries routinely monitor and control blending using near‐infrared (NIR) spectroscopy. A comparable development to monitor polymer molar masses on‐line from systems already being used to measure density and melt index, would be of potential value to many sectors of the polymer production and processing industry.Chemometrics is a multivariate methodology that allows the information from entire spectra to be used; it can be considered as a maximal compression technique. Extracted ‘factors’ can then be regressed against property data by using a well‐characterized set of ‘training’ samples to produce predictive regression models. We will show that simple spectroscopic methods, such as the Raman technique discussed in this paper, when coupled with chemometrics, are capable of providing molar mass and distribution information. We will illustrate this with reference to poly(dimethylsiloxane)s (PDMSs) in the liquid phase.© 2000 Society of Chemical Industry

We have studied the Raman spectrum of β-carotene using excitation wavelengths from visible (514.5 nm) to near-infrared (1064 nm). Qualitatively, the spectrum appears independent of the choice of excitation wavelength, although this is not true in detail; in particular, the ratio of the intensities of the νC-Cand νC=Cfundamentals to their overtones and combinations varies with the excitation wavelength. The inelastic neutron scattering spectrum shows no evidence for unusual dynamics in this system, and the UV/vis/NIR spectrum shows that there are no allowed electronic transitions from the ground state beyond ∼700 nm. These observations provide strong evidence for the existence of a different mechanism for the enhancement of the bands. Indirect evidence suggests that, with these longer excitation wavelengths, the intensities of the νC-Cand νC=Cpeaks are at least two orders of magnitude smaller than those from resonance enhancement with the use of excitation into the visible absorption bands. The implications for the characterization of polyenes in polymers are discussed.

High resolution, high signal-to-noise ratio Fourier transform Raman (1 cm) and infrared spectra of perdeutero-polyethylene have been measured Observation of the residual isolated C&z.sbnd;H stretch modes has been used to derive a C&z.sbnd;H bond distance in reasonable agreement with experimental data. Some combination and overtone modes are observed and assigned for the first time. The high resolution has allowed upper limits for the correlation splitting of the Raman bands to be set. Curve resolution of the broadest band, 1251 cm has allowed observation of the correlation split components and a third band that is assigned to the amorphous region of the polymer.

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