The Experts below are selected from a list of 33 Experts worldwide ranked by ideXlab platform
Tonka Kovačić - One of the best experts on this subject based on the ideXlab platform.
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Influence of MBS on the thermooxidative degradation of stabilized and nonstabilized PVC/MBS blends
2020Co-Authors: Branka Andričić, Tonka KovačićAbstract:The thermooxidative degradation of PVC/MBS blends with/without thermal Stabiliser for PVC was investigated by dynamic thermogravimetry in air. Thermooxidative degradation proceeds through three main degradation steps. The first one corresponds to the dehydrochlorination (DHC) of PVC followed by the polyene oxidation ; the second and the third steps correspond to the simultaneous degradation of PVC and MBS. It was found that, besides PVC, the thermal Stabiliser stabilises MBS, too. The mass loss in the first degradation step is a few percents higher in stabilised PVC/MBS samples. Comparison of experimental and theoretical TG curves of the blends shows the stabilising effect of MBS on dehydrochlorination and the opposite effect on further degradation. This is more pronounced in stabilised blends with higher amount of MBS. Relative DHC rate in the blends with respect to pure PVC differs in stabilised and nonstabilised blends and implies additional stabilising effect of MBS in the stabilised blends. The kinetic parameters of the first degradation step were estimated by Kissingers equation. In both blend series the linear relationship between Arrhenius parameters E and A was found and the compensation parameter Sp* was taken as a measure of system reactivity, although there are many controversies about Sp*. Generally, the higher value of the parameter means the lower reactivity of the system. The lowest Sp* is exhibited by the samples with 15 and 20 phr of MBS in nonstabilised blends, and with 20 and 30 phr of MBS in stabilised ones. Glass transition temperature (Tg) of PVC in the blends, determined by DSC, shows no interaction of PVC with glassy phase of MBS. PVC in stabilised blends has lower Tg than in unstabilised blends due to the presence of Heat Stabiliser as a low molecular component miscible with PVC.
Maatoug A. Maatoug - One of the best experts on this subject based on the ideXlab platform.
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Effect of interface modification on the photo-stability of pigmented polyethylene films
Polymer Degradation and Stability, 2015Co-Authors: Péter Anna, Gy. Bertalan, Gy. Marosi, I. Ravadits, Maatoug A. MaatougAbstract:The deterioration of differently stabilised and pigmented high density polyethylene films was investigated by DSC and UV spectroscopy methods in the course of accelerated photo-ageing and compared to earlier XPS and gel-content results. Unexpectedly quick destruction of phthalocyanine containing film was observed and explained by the adsorptive removal of the Stabiliser from the polymer matrix. In the pigment (filler)-solvent-Stabiliser model systems the high susceptibility of hindered phenol type Heat-Stabiliser to adsorb on talc and phthalocyanine pigment was proved by UV spectroscopic measurements. Surface coating of the talc and pigment with a reactive surfactant considerable reduced the adsorption capacity and thus improved the photo-stability of the pigmented film.
Baby Kuriakose - One of the best experts on this subject based on the ideXlab platform.
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Studies on epoxidised rubber seed oil as secondary plasticiser/Stabiliser for polyvinyl chloride
Plastics Rubber and Composites, 2004Co-Authors: Rani Joseph, K. N. Madhusoodhanan, Rosamma Alex, Siby Varghese, K. E. George, Baby KuriakoseAbstract:Abstract Rubber seed oil (RSO) and epoxidised rubber seed oil (ERSO) were used as secondary plasticiser cum Heat Stabiliser in polyvinyl chloride (PVC). High temperature mixing studies, dynamic mechanical analysis, hot air aging tests and colour stability tests indicated that ERSO could be used as a less volatile secondary plasticiser and Heat Stabiliser for PVC in combination with dioctyl phthalate (DOP). The tensile properties of the compound containing 50 : 10 DOP/ ERSO were found to be comparable to that containing 60 parts of DOP per 100 parts PVC.
Branka Andričić - One of the best experts on this subject based on the ideXlab platform.
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Influence of MBS on the thermooxidative degradation of stabilized and nonstabilized PVC/MBS blends
2020Co-Authors: Branka Andričić, Tonka KovačićAbstract:The thermooxidative degradation of PVC/MBS blends with/without thermal Stabiliser for PVC was investigated by dynamic thermogravimetry in air. Thermooxidative degradation proceeds through three main degradation steps. The first one corresponds to the dehydrochlorination (DHC) of PVC followed by the polyene oxidation ; the second and the third steps correspond to the simultaneous degradation of PVC and MBS. It was found that, besides PVC, the thermal Stabiliser stabilises MBS, too. The mass loss in the first degradation step is a few percents higher in stabilised PVC/MBS samples. Comparison of experimental and theoretical TG curves of the blends shows the stabilising effect of MBS on dehydrochlorination and the opposite effect on further degradation. This is more pronounced in stabilised blends with higher amount of MBS. Relative DHC rate in the blends with respect to pure PVC differs in stabilised and nonstabilised blends and implies additional stabilising effect of MBS in the stabilised blends. The kinetic parameters of the first degradation step were estimated by Kissingers equation. In both blend series the linear relationship between Arrhenius parameters E and A was found and the compensation parameter Sp* was taken as a measure of system reactivity, although there are many controversies about Sp*. Generally, the higher value of the parameter means the lower reactivity of the system. The lowest Sp* is exhibited by the samples with 15 and 20 phr of MBS in nonstabilised blends, and with 20 and 30 phr of MBS in stabilised ones. Glass transition temperature (Tg) of PVC in the blends, determined by DSC, shows no interaction of PVC with glassy phase of MBS. PVC in stabilised blends has lower Tg than in unstabilised blends due to the presence of Heat Stabiliser as a low molecular component miscible with PVC.
Galo Le A C Roux - One of the best experts on this subject based on the ideXlab platform.
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development of a mixture design methodology for problems with incomplete information application to pvc Heat Stabiliser design
Computer-aided chemical engineering, 2006Co-Authors: Ulisses G Da Cruz, Galo Le A C RouxAbstract:Abstract The objective of this work is to optimize the formulations of Heat stabilizers for PVC (Poly Vinyl Chloride) by means of mixture design techniques extended to deal with problems with incomplete information. The mixture design problem consists in minimizing the cost of the formulation while obtaining a product that satisfies technical and market specifications. In the case studied, the formulations are mixtures of 8 to 10 components chosen out from 16 basic compounds. Each of the compounds confers different characteristics to the final formulation, and there can be interactions between them. The mixture characteristics of interest are obtained from assays performed in a standard torque rheometer for different stabilizer, formulations. Data from a database, in which many different test and commercial formulations are recorded, were used in order to build models that correlate the properties with the compositions. As the number of data points that would be needed in order to obtain the necessary information for a complete description of the mixture would be prohibitive, mixture models were built using Principal Components Regression (PCR). The mixture design problem can be expressed as Linear and Nonlinear depending on the type, of model used. In order to avoid extrapolation problems that would result from the poor availability of information, additional equations that confines the solution to the subset where information is available (the space spanned by the main principal components retained for correlation) are added to the problem. This is an extension to the standard mixture design problem. Solutions obtained are compared to validation experiments which shows that the methodology is very promising for industrial design problems.