Authors:T. Vilics, H. A. Schneider, Virginia Manoviciu, and I. Manoviciu
A new criterion for evaluating different plasticizers the ability of suppression of the Β transition in plasticized PVC blends. Accordingly, the Β suppression ability is proportional to the PVC-plasticizer compatibility, expressed either by the critical solution temperature, CST, or by the interaction parameter related to the difference between the solubility parameters of the blend components. The criterion is, however, valid for low plasticizer contents (<5%w/w) only, as long as the Β transitions are not overlapped by the α transitions, shifted towards lower temperatures due to the effect of the plasticizer. For higher plasticizer contents the α transition starts to overlap the Β transition and the Β suppression ability of the plasticizer depends increasingly on the efficiency of the plasticizer i.e. on the depression of the glass transition temperature of PVC (related to theTg of the plasticizer). Accordingly, plasticizers with both good efficiency (lowTg) and compatibility are more effective in the Β suppression than plasticizers which have only a higher compatibility but also a highTg (i.e. reduced efficiency).
Authors:F. Pruneda, J. J. Suñol, F. Andreu-Mateu, and X. Colom
Summary Nitrile butadiene rubber (NBR) and NBR/PVC blends were produced using 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) or not as antioxidant. Controlled ozone degradation was performed in several samples. Thermal, compositional and morphological analysis was performed by means of differential scanning calorimetry, thermogravimetry, chemical analysis and scanning electron microscopy. Thermogravimetry analysis shows four mass loss processes related to plastizicer, complex rubber degradation and metallic oxides and other additives. In NBR (NBR/PVC blends) the onset temperature of the first degradation process varies between 227-231°C (259-262°C) and the apparent activation energy between 26 and 36 kJ mol-1 (36-57 kJ mol-1), the NBR/PVC samples non degraded presents the higher thermal stability.
Authors:Asma Afzal, Muhammad Akhtar, and Lars-Gunnar Svensson
A series of blends of dodecylbenzenesulfonic acid (DBSA)-doped polyaniline (PANDR) and PVC were synthesized by solution blending
technique and investigated by heatflow microcalorimetry (HFC) for thermal and oxidative stability and for PVC–PANDR compatibility.
FTIR results provided evidence for strong dipole–dipole interactions between PANDR and PVC. The energy of the oxidation is
independent of the composition. The interaction energy and thermal stability increased with the increase of PANDR content
in the blend. The activation energies calculated by using Arrhenius relationship can be employed for accelerated ageing of
the synthesized blends. It has been observed that the average degradation of PANDR component is higher than that of PVC.
Authors:Vadim V. Krongauz, Yann-Per Lee, and Anthony Bourassa
-ethylhexyl)phthalate (DEHP) (Sigma-Aldrich), or tris(2-ethylhexyl) trimellitate (TOTM) (Eastman) plasticizer and PVCblend extruded as a 0.3 mm thick film at 170 °C. Small constant amount of epoxydized oils was present in DEHP and TOTM-plasticized samples
The influence of some irregularities in polystyrene (PS) and polyvinyl chloride (PVC) chains on their thermal stability was investigated. UV irradiation caused an increase in the content of these irregularities in the polymers. It was found that the presence of carbonyl groups and crosslinking of the polymer chains hamper the thermal dehydrochlorination of PVC and the total decomposition of both polymers. On the other hand, weak peroxy linkages (which facilitate degradation processes) and conjugated double bonds decrease the temperature of total decomposition of PS and PVC blends.
Authors:K. Agarwal, M. Prasad, A. Chakraborty, C. B. Vishwakarma, R. B. Sharma, and D. K. Setua
, EVA, or CSM. However, the addition of PVC shows a decrease in the maximum rate of expansion. For contraction and maximum rate of contraction, the absolute values were reduced in NBR for all its blends with minimum in the case of NBR/CSM. The NBR/PVC
Authors:S. H. Murphy, G. A. Leeke, and M. J. Jenkins
. However, in recent years, the use of infrared spectroscopy as a method of characterisation of crystallinity has grown in prominence. In the case of PCL, one of the first and often cited studies concerned the study of a PCL/PVCblend system using FTIR