Results 1 - 10 of 2093
Results 1 - 10 of 2093. Search took: 0.029 seconds
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[en] Process for preventing the modification of a polymer whose molecule contains a halogen, under the effect of an ionizing radiation, consisting in adding to this polymer a heat stabilizing metal-based agent, and a mercaptan, characterized in that hydroquinone is also added
[fr]Procede pour empecher l'alteration d'un polymere dont la molecule renferme un halogene, sous l'effet d'un rayonnement ionisant, qui consiste a incorporer a ce polymere un stabilisant a la chaleur, a base de compose metallique, et un mercaptan, caracterise en ce qu'on incorpore egalement de l'hydroquinone
[en] Sugarcane bagasse is divided into two major components. They are pith and rind. Pith is the inner part of sugarcane bagasse while rind is the outer part of it. In this study, the flexural properties of pith reinforced poly (vinyl chloride) composites were compared to that of rind composites with the same matrix in variation of fibre content. The composites were produced by compression moulding method. The fibre contents were 10%, 20%, 30%, 40%, and 50% in weight. Three-point bending tests were carried out to measure the flexural properties of the composites. It has been found that, in general, the addition of fibre improved the flexural modulus of the materials. Meanwhile, the rind composites were of superior flexural properties compared to the pith composites.
[en] The complexation of N,N'-4,5-(ethylenedioxy)benzenebis(salicylideneimine), (salphenH2) with uranyl ion was studied in acetonitrile solution spectrophtometrically, and the formation constant of the resulting 1 : 1 complex was evaluated. The salphenH2 ligand was used as an ionophore in plasticized poly(vinyl chloride) (PVC) matrix membrane sensor for uranyl ion. The prepared sensors exhibited a near Nernstian response, 28.0-30.9 mV/decade for uranyl ion over the concentration range 1.0 x 10-2 to 1.0 x 10-6 M with a limit of detection of 3.2 x 10-7 M. The proposed electrode could be used at a working pH range of 1.5-4.0
[en] The studies presented enable to evaluate the survival rate of the protozoons in contact with the studied polymers-folis, from polyethylene PE, polyvinyl chloride P-25, polyester E1 and irradiated collagen L7. It can also be established whether the change of certain morphodynamic parameters could be used to evaluate biological usefulness of plastics. Stereometric method and factor analysis were used in the studies. On the basis of the obtained data polyvinyl chloride P-47 was well assessed, while irradiated collagen L7 showed most negative features. (author)
[en] The use of biobased plasticizers with low toxicity and good compatibility with polyvinyl chloride (PVC) has become more attractive in the recent years in contrast with phthalate derivatives. In this study, a glycerol derivative plasticizer (triacetin—TAG) was tested as a secondary plasticizer for PVC. TAG was added to PVC formulations from 10 up to 20 phr. The increase of the plasticizer content had a great influence on the properties of PVC samples. The good miscibility and therefore the efficient plasticization action of the TAG were supported by DMA results, since narrow peaks of tan (δ) curves and reduction of the Tg values for the samples were observed. The ensuing PVC demonstrated good rheological properties and thermal stability up to 200 °C. Finally, the presence of TAG reduces the hardness of materials and does not increase their density.
[en] Up to 1980 the cable industry has used halogen-containing compounds on a large scale which have excellent properties, but are hazardous if fire breaks out. Hence halogen-free compounds have an increasing share in today's market. Halogen-free polymer developments have shown difficulties optimizing interdependent properties such as cross-linking, to meet the German standards and ease of extrusion. Cross-linking by radiation, e.g. electron beam, allows changing of specific properties to meet special requirements. 1 tab
[en] Full Text: In field of few (0,1 - 10 mass%) components concentration an electrical aging of PEVC-PP mixture gained from fusion and PS-PVC prepared from solution has been under research. It's discovered that a few addition of PE (1-2 mass%) to PP considerably intensifies the electrical properties changing and PP erosion. It's also observed a quick abnormal destruction of PS-PVC during addition of PVC with concentration of 1% mass but few of PS don't influence a collapse of PVC
[en] Avocados were irradiated with gamma rays (Cs-137) and subjected to thermal treatment. Relative humidity (RH) is an important factor in this preservation; the higher the RH the longer the shelf-life. PVC was used to maintain the humidity of the fruits
[en] Complete text of publication follows. The widely using of organotin compounds in polyvinyl chloride (PVC) stabilization, antifouling paints and biocides has resulted in serious problems. In order to monitor and assess the contamination of organotin compounds in the environment, an accurate, simple and cost-effective speciation method is imperative. Atomic fluorescence spectrometry (AFS), as a very sensitive and selective method for determination of some elements, was frequently coupled to GC or LC for speciation analysis in recently years. However, except for As, Hg and Se, AFS is seldom used for speciation of other elements (such as tin and lead etc.), even though it is also sensitive and selective for determination of them. In this work, a laboratory-established capillary GC-AFS system was attempted to analyze butyltin species in water samples. The butyltin compounds were extracted and pre-concentrated with headspace solid-phase microextraction (SPME) technique after hybridization using KBH4. The experimental conditions, including the carrier gas, argon and hydrogen flow rates and the lamp current were optimized in detail. Under the optimum conditions, the detection limits for monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT), calculated as three times of the standard deviation of the baseline noise, were 10, 0.2 and 0.1 ng Sn mL-1, respectively. The relative standard deviations (RSD) of five replicates were 5.2%, 7.4% and 7.1% for MBT, DBT and TBT, respectively. The linear dynamic ranges of MBT, DBT and TBT were found very long. The recoveries of MBT, DBT and TBT in three different water samples (seawater, tap water and wastewater) were between 72.1% and 97.9%, indicating that the proposed method was accurate and feasible to speciation analysis of butyltin compounds in water samples.