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- Gómez-Heincke, Diana, et al.
(författare)
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Improvement of mechanical and water absorption properties of plant protein based bioplastics
- 2017
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X .- 1873-7137. ; 73, s. 21-29
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Tidskriftsartikel (refereegranskat)abstract
- Bioplastics deriving from plant proteins are becoming an increasingly popular source of raw material for plastic products since they are not only biodegradable but renewable resources. However, these bioplastics require improved mechanical and water absorption properties to be suitable for many applications, such as packaging. For this reason, this study considers potato and rice proteins as a new source for the manufacture of bioplastics. The proteins were mixed with different glycerol concentrations followed by thermomoulding at temperatures from 60 to 180 °C. The resulting bioplastic is characterized in terms of thermo-mechanical properties, water absorption and molecular weight distribution. Compared to well-known wheat gluten, these bioplastics required higher temperatures for their thermomoulding. However, both of them were more structured materials and exhibited less water absorption (e.g. as low as 9 wt.%) than those obtained for wheat gluten blend. Potato protein-based bioplastics showed complex modulus values comparable to synthetic polymers such as Low Density Polyethylene (LDPE).
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| 2. |
- Mauri, Massimiliano, 1987, et al.
(författare)
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Click chemistry-type crosslinking of a low-conductivity polyethylene copolymer ternary blend for power cable insulation
- 2020
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Ingår i: Polymer International. - : Wiley. - 1097-0126 .- 0959-8103. ; 69:4, s. 404-412
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Tidskriftsartikel (refereegranskat)abstract
- High-voltage direct-current power cables are vital for the efficient transport of electricity derived from renewable sources of energy. The most widely used material for high-voltage power cable insulation - low-density polyethylene (LDPE) - is usually crosslinked with peroxides, a process that releases unwanted by-products. Hence, by-product-free crosslinking concepts that mitigate the associated increase in electrical conductivity are in high demand. Click chemistry-type crosslinking of polyethylene copolymer mixtures that contain glycidyl methacrylate and acrylic acid co-monomers is a promising alternative, provided that the curing reaction can be controlled. Here, we demonstrate that the rate of the curing reaction can be adjusted by tuning the number of epoxy and carboxyl groups. Both dilution of copolymer mixtures with neat LDPE and the selection of copolymers with a lower co-monomer content have an equivalent effect on the curing speed. Ternary blends that contain 50 wt% of neat LDPE feature an extended extrusion window of up to 170 degrees C. Instead, at 200 degrees C rapid curing is possible, leading to thermosets with a low direct-current electrical conductivity of about 10(-16) S cm(-1) at an electric field of 20 kV mm(-1) and 70 degrees C. The conductivity of the blends explored here is comparable to or even lower than values measured for both ultraclean LDPE and a peroxide-cured commercial crosslinked polyethylene grade. Hence, click chemistry curing represents a promising alternative to radical crosslinking with peroxides. (c) 2019 Society of Chemical Industry
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