ABSTRACT The stability of electrical and mechanical properties of two kinds of polymer composites... more ABSTRACT The stability of electrical and mechanical properties of two kinds of polymer composites - polyethylene/carbon black and polyethylene/carbon black modified by polypyrrole - was investigated during slow cycle heating and cooling. Conductivity in composites was measured in heating/cooling cycles in the temperature range from 16°C to 125°C. It was found that the thermal treatment resulted in the conductivity changes and the mechanical properties of treated composites have also been influenced. The effect was explained by increased crystallinity in the polymer matrix of thermally treated composites.
ABSTRACT Crosslinking of polypropylene was investigated when initiated by thermal decomposition o... more ABSTRACT Crosslinking of polypropylene was investigated when initiated by thermal decomposition of organic peroxides. p-Benzoquinone was found to be an effective coagent of crosslinking. The efficiency of benzoquinone is about 5 times higher than that of polyfunctional monomers. Almost complete crosslinking of polypropylene can be reached at proper conditions.
Poly(imide-siloxane) (PIS) block copolymers have been studied with respect to their structure and... more Poly(imide-siloxane) (PIS) block copolymers have been studied with respect to their structure and surface properties relationship. The relatively small amount of siloxane in PIS block copolymer, 10-20 wt.%, increased significantly the contact angle of water due to the surface hydrophobization of the copolymer. The significant decrease of the surface energy of the PIS copolymer due to growth of the siloxane content was observed. The polar component of surface energy shows an intense decrease, whereas its dispersive component increases. The study of the morphology of PIS copolymers characterized by The X-ray Photoelectron Spectroscopy (XPS) analysis showed an excessive increase of Si on the polymeric surface. Scanning electron microscopy (SEM) shows a growth of the surface roughness by increase of the content of siloxane.
ABSTRACT The stability of electrical and mechanical properties of two kinds of polymer composites... more ABSTRACT The stability of electrical and mechanical properties of two kinds of polymer composites - polyethylene/carbon black and polyethylene/carbon black modified by polypyrrole - was investigated during slow cycle heating and cooling. Conductivity in composites was measured in heating/cooling cycles in the temperature range from 16°C to 125°C. It was found that the thermal treatment resulted in the conductivity changes and the mechanical properties of treated composites have also been influenced. The effect was explained by increased crystallinity in the polymer matrix of thermally treated composites.
ABSTRACT Crosslinking of polypropylene was investigated when initiated by thermal decomposition o... more ABSTRACT Crosslinking of polypropylene was investigated when initiated by thermal decomposition of organic peroxides. p-Benzoquinone was found to be an effective coagent of crosslinking. The efficiency of benzoquinone is about 5 times higher than that of polyfunctional monomers. Almost complete crosslinking of polypropylene can be reached at proper conditions.
Poly(imide-siloxane) (PIS) block copolymers have been studied with respect to their structure and... more Poly(imide-siloxane) (PIS) block copolymers have been studied with respect to their structure and surface properties relationship. The relatively small amount of siloxane in PIS block copolymer, 10-20 wt.%, increased significantly the contact angle of water due to the surface hydrophobization of the copolymer. The significant decrease of the surface energy of the PIS copolymer due to growth of the siloxane content was observed. The polar component of surface energy shows an intense decrease, whereas its dispersive component increases. The study of the morphology of PIS copolymers characterized by The X-ray Photoelectron Spectroscopy (XPS) analysis showed an excessive increase of Si on the polymeric surface. Scanning electron microscopy (SEM) shows a growth of the surface roughness by increase of the content of siloxane.
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