| 1. |
- Lindberg, Henrik, et al.
(författare)
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Chlorine loss and mass loss from Polyvinylchloride and polyvinylidenchloride under the electron beam
- 1985
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Ingår i: Journal of Materials Science. - 0022-2461 .- 1573-4803. ; 20:6, s. 2225-2232
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Tidskriftsartikel (refereegranskat)abstract
- The loss of chlorine during the irradiation of PVC and PVDC in the electron microscope has been measured by the decay of the X-ray chlorine Kα signal. A number of factors affecting the measured beam damage curves have been considered and the experimental errors reduced to ±10%. The results show that the chlorine decay curves can be best described by the sum of two exponentials, corresponding to the two different chlorine decay processes, these being: the dehydrochlorination of the polymer molecules and the dehydrochlorination of the polyene structure formed by the beam damage. The higher initial chlorine content of PVDC compared to PVC will result in a larger amount of chlorine atoms reacting with the polyene structure, which is more stable in the electron beam than the undamaged polymer. The chlorine loss, measured by X-ray analysis, has been compared to the mass loss, measured by energy loss analysis, and also with the volume changes of isolated spherical PVC particles. It has been concluded that the mass loss is almost entirely due to chlorine loss and that the residual structure has a density similar to the undamaged PVC.
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| 2. |
- Lindberg, Henrik, et al.
(författare)
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Effects of the addition of a multiblock copolymer to an incompatible blend
- 1990
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Ingår i: Plastics and Rubber Processing and Applications. - 0144-6045. ; 14:7, s. 195-202
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Tidskriftsartikel (refereegranskat)abstract
- The morphology and mechanical properties of the immiscible blend HDPE/PA6 have been studied with respect to the effects of the addition of small amounts of a PA6--PB multiblock copolymer. The copolymer was found to interact with the binary blend. The particle size of the dispersed PA6 phase was reduced. Melt viscosity measurements showed strong phase interaction. TEM studies showed that the copolymer was located in interfacial areas, but not covering the surface of the PA6 phase. Moreover, some copolymer was distributed within the PA6 phase and the HDPE matrix and small amounts also formed a separate phase. Stress, strain and creep properties were not improved by the addition of the block copolymer with the exception of an improved elongation at break. Though the copolymer has not been found to act as a powerful compatibilizer, the results indicate that multiblock copolymers with short blocks have a potential as interesting modifers in immiscible blends.
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| 3. |
- Lindberg, Henrik, et al.
(författare)
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Electron beam damage of some chlorine containing polymers and PVC blends
- 1989
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Ingår i: Journal of Materials Science. - 0022-2461 .- 1573-4803. ; 24:8, s. 2825-2832
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Tidskriftsartikel (refereegranskat)abstract
- The electron beam damage of PVC, PVDC, chlorinated PE, chlorosulphonated PE (Hypalon) and chloroendic acid polyester has been studied by chlorine loss and mass loss measurements. The mass loss decay curves have been recalculated for true mass loss and correlated with the X-ray measurements of chlorine loss. It is shown that the major mechanism of degradation in these polymers is dehydrochlorination. The rate of dehydrochlorination is dependent on the chemical structure of the polymer, and in particular on the availability of hydrogen for HCl formation. However, in case of chloroendic acid polyester, more complicated volatile chlorinated compounds are also formed. The dehydrochlorination rate and mass loss of miscible PVC blends, namely PVC with organotin stabilizer, PMMA, PCL and SAN have been studied. The rate of chlorine loss from PVC was found to be unchanged for all blends except for PMMA and PCL, where it slightly increased due to the chemical reaction between the molecular fragments of both polymers. The differences between the thermal degradation and electron beam damage are also discussed.
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| 4. |
- Lindberg, K. A. H., et al.
(författare)
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Morphology of polyamide 6-polybutadiene multiblock copolymers
- 1991
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Ingår i: Journal of Materials Science. - 0022-2461 .- 1573-4803. ; 26:16, s. 4383-4388
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Tidskriftsartikel (refereegranskat)abstract
- The morphology of polyamide 6-polybutadiene multiblock copolymers, commonly used for reaction injection moulding, have been investigated using transmission electron microscopy, dynamic mechanical techniques, calorimetry and wide angle X-ray diffraction. Phase separation is found to be almost complete and the crystallization of the PA6 blocks is slightly higher than in pure PA6. The morphology shows similarities to what has been reported for segmented polyether-esters. The PA6 lamellar dimensions found in the micrographs agree with dimensions calculated from melting point depression and X-ray data.
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| 5. |
- Sathik, J., et al.
(författare)
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A multilevel inverter topology using diode half-bridge circuit with reduced power component
- 2021
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 14:21
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a new multilevel converter with a reduced number of power components for medium voltage applications. Both symmetric and asymmetric structures of the presented multilevel converter are proposed. The symmetric topology requires equal dc source values, whereas the asymmetric topology uses minimum switch count. However, both structures suffer from high blocking voltage across the switches. To reduce the blocking voltage on switches, an optimal topology is presented and analyzed for the selection of the minimum number of switches and dc sources, while maintaining a low blocking voltage across the switches. A comparative analysis with recently published topologies was performed. The simulation results, as well as the comparative analysis, validated the robustness and effectiveness of the proposed topology in terms of the reduced power loss, lowered number of components, and cost. Furthermore, in addition to the simulation results, the performance of the proposed topology was verified using experimental results of 9, 17, and 25 evels.
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