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1.
The influence of photodegradation and weathering on the water vapour sorption kinetic behaviour of scots pine earlywood and latewood 总被引:1,自引:0,他引:1
Victoria Sharratt Callum A.S. HillJalaludin Zaihan Darwin P.R. Kint 《Polymer Degradation and Stability》2011,96(7):1210-1218
The effect of weathering or accelerated photodegradation on the water vapour sorption kinetics of Scots pine (Pinus sylvestris) has been studied. The sorption kinetics were analysed using the parallel exponential kinetics (PEK) model and the parameters obtained used as input into a Kelvin-Voigt thereby providing values for the wood cell wall stiffness and viscosity. Differences in kinetic behaviour were found between earlywood and latewood samples, and between samples which had been photodegraded or weathered when compared to unexposed samples. The values for the cell wall stiffness are in general agreement with values previously published in the literature. 相似文献
2.
The sorption mechanism of Al3+ on chelating resins by means of mathematical analysis of sorption isotherms using nonlinear mean square software was studied. This method should yield more detailed information than classical thermodynamics and should be more flexible than the statistical-mechanical method, so that it would make it possible to obtain fairly easily relations directly applicable in practice. This model defined the specific potential ΦAlR for the ion in a resin (which depends on properties of resin and ion). On the basis of this model, N and PO isotherms were derived. To study the sorption mechanism, the Freundlich, Langmuir, N and PO equations (models) of isotherms were used. It was estimated that the functional groups (8-hydroxyquinoline and salicylate) in the studied chelating resins influence ΦAlR and thus their mechanism and sorption capacity. 相似文献
3.
Victoria Sharratt Callum A.S. Hill Darwin P.R. Kint 《Polymer Degradation and Stability》2009,94(9):1589-1594
A detailed study of early colour change in Scots pine (Pinus sylvestris) due to accelerated simulated sunlight exposure was undertaken focusing on the first 24 h of change. Colour changes were monitored with a Datacolor check spectrophotometer and compared with a set of controls. Measurements on both samples and controls were performed hourly for the first 24 h and there after daily until 168 h’ exposure with extra measurements at 200, 350 and 500 h. A subset of samples was extracted prior to exposure to check the effects of any colour change due to the presence of extractives. Data was analysed using the reflectance spectra (400–700 nm) as well as the CIE-L*a*b* system and ΔE. The majority of colour changes were found to occur within the first 24 h. This was unaffected by the removal of extractives from the wood and was independent of temperature. Mechanical properties and weight changes were also monitored to allow a comparison of sensitivity between the differing methods. 相似文献