Polyamide thermal recycling

Sukri, S. M., Suradi, N. L., Arsad, A., Rahmat, A. R., Hassan, A., Green composites based on recycled polyamide-6/recycled polypropylene kenaf composites mechanical, thermal and morphological properties. J Polym Eng, 32(4-5), 291-299 (2012). 

Recently the pyrolysis of polymer mixtures has become a focus of interest due to the increasing role of plastics recycling. Many researchers have investigated the thermal decomposition of various polymers in the presence of PVC. Kniimann and Bockhom [25] have studied the decomposition of common polymers and concluded that a separation of plastic mixtures by temperature-controlled pyrolysis in recycling processes is possible. Czegfny et al. [31] observed that the dehydrochlorination of PVC is promoted by the presence of polyamides and polyacrylonitrile however, other vinyl polymers or polyolefins have no effect on the dehydrochlorination. PVC generally affects the decomposition of other polymers due to the catalytic effect of HCI released. Even a few per cent PVC has an effect on the decomposition of polyethylene (PE) [32], HCI appears to promote the initial chain scission of PE. Day et al. [33] reported that PVC can influence the extent of degradation and the pyrolysis product distribution of plastics used in the... 

Hassan, M. M., Badway, N. A., Gamal, A. M., Elnaggar, M. Y, Hegazy E.-S. A., Studies on mechanical, thermal and morphological properties of irradiated recycled polyamide and waste rubber powder blends. Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 2010, 268, 1427-1434. 

Recycling has a dramatic influence on the mechanical and thermal properties of unstabilised polyamide 66. However, glass fibre reinforced polyamide 66 may be recycled up to four times without any significant deterioration in the performance of the material. Proper amounts and combinations of processing additives and antioxidants, together with optimised processing parameters, make it possible to recycle polyamides without significant losses of mechanical properties. 

Another new product is Saytex HP-7775. This is an extruded blend of brominated polyst5rene (HP-7010 from Albemarle) and Sb203 in a ratio of 77.5/22.5. It comes as dust-free, fi ee-flowing granules. It provides outstanding thermal stability and electrical performance, making it ideal for polyamides and polyesters in electrical applications. It has excellent mechanical properties, flow, non-blooming and, not least, recyclability, all similar to the basic brominated polystyrene. 

Effect of Thermal-Oxidative Ageing on Mechanical, Chemical, and Thermal Properties of Recycled Polyamide 66, Journal of Applied Polymer Science, 65 (1997), p. 1619 - 1630... 

There are forms of recycling that are less familiar —in that they do not directly recycle the materials into new artifacts. Tertiary recycling breaks down the plastic to its component monomers, which can be repolymerized. This requires pyrolysis of the materials, sometimes called thermal cracking, and is most easily accomplished with step growth polymers such as polyamides and polyesters but is also possible for poly(methyl methacrylate). The processes require specialized plant, so are capital intensive, and a large-scale operation is necessary for economic viability. 

MORPHOLOGICAL, THERMAL AND MECHANICAL PROPERTIES OE GREEN COMPOSITE BASED ON RECYCLED POLYETHYLENE/ POLYAMIDE-6/KENAE COMPOSITES... 

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