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Thermal degradation behavior and flammability of polyurethanes blended with poly(bispropoxyphosphazene)
October/No~,enlher
ABSTRACTS Engineering Information’s Compendex database reviewed for additives’ literature in 1999-2000
The following abstracts from 1999-2000 are drawn from Compendex via Elsevier Advanced Technology’s sister company Engineering Information (Ei). For further information concerning Ei and its services such as the Engineering Village, please consult the homepage at: www.ei.org.
An extremely useful technique for studying polymer degradation Wilkitj, Churles A..Marquette Univer,vity,Mil\\wukee, USA in Polymer Degrudution und Stubility, Volume 66 tss~w 3, 1999. Thermogravimetric analysis coupled to Fourier transform infrared spectroscopy, TGA/FTIR, has been used to probe the degradation of several polymeric systems. These include poly( methyl methacrylate) in the presence of various additives, graft copolymers of acrylonitrile-butadiene-styrene and styrene-butadiene with sodium methacrylate and styrene with acrylonitrile, blends of styrene-butadiene block copolymers with poly(vinylphosphonic acid) and poly(vinylsulfonic acid), and cross-linked polyslyrenes. Additives may interact with poly(methyl methacrylate) by coordination to the carbonyl oxygen to a Lewis acid and the subsequent transfer of an electron from the polymer chain to the metal atom or by the formation of a radical which can trap the degrading radicals before they can undergo further degradation. When an inorganic char-former is graft copolymerized onto a polymer, there is a good correlation between TGA behavior in an inert atmosphere and thermal stability in air, but this is not true when the char is largely carbonific.
02000 Elsevier Science
Additives fiw Polvmers
Thermal degradation behavior and flammability of polyurethanes blended with poly(bispropoxyphosphazene) Wung, Pin-Sheng, Chiu, Wen- Yen, Chen, Leo- Wang, Denq, Bar-Long, Don, Trong-Ming, Chiu, Yie-Shun, National Taiwan Crniversity, Taipei, Taiwan in Polymer Degradation and Stabiliv, Vol66 No 3, 1999. Polyurethanes containing different amount of flame retardant, poly(bispropoxyphosphazene). were synthesized by a two-step polymerization.The thermal degradation behaviors of these polyurethanes were then studied by the thermal gravimetric analysis (TGA), TGA coupled with Fourier transform infrared analysis and elemental analysis. A limiting oxygen index was used to evaluate the flammability of these polyurethanes. For these modified polyurethanes under nitrogen, a two-stage thermal degradation behavior was observed. The first stage was caused by the degradation of hard segments. whereas the soft segments were responsible for the second-stage degradation. The thermal degradation activation energies were calculated by using Ozawa’s method. It was found that the addition of flame retardant caused a decrease of the activation energy in the first stage, but an increase in the second stage. which was probably due to the formation of a thermal stable structure. As for the flame retardany, the modified poly-urethanes have a higher char yield at 550$DGR@C, and a higher limiting oxygen index than the neat polyurethane.
Effect of coagent in reactive surface treatment for calcium carbonate filler in polypropylene Tabtinng, A., Vuubles, R.A., Mahidol Unitersif[)‘,Bangkok. Thailand in Plastics, Rubber and Composites, Vol28 Issue 1, 1999. Calcium carbonate as a filler for polypropylene has been modified with a reactive coupling system comprising acrylic acid (AA) and dicumyl peroxide(DCP), to promote coupling through grafting at the surface of the filler during melt compounding, in conjunction with trimethylolpropane trimethacrylate coagent (TMP) to limit degradation. The main effects and interactions between these three additives have been assessed via their influence upon selected characterization data. Inferences from
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ABSTRACTS Engineering Information’s Compendex database reviewed for additives’ literature in 1999-2000
The following abstracts from 1999-2000 are drawn from Compendex via Elsevier Advanced Technology’s sister company Engineering Information (Ei). For further information concerning Ei and its services such as the Engineering Village, please consult the homepage at: www.ei.org.
An extremely useful technique for studying polymer degradation Wilkitj, Churles A..Marquette Univer,vity,Mil\\wukee, USA in Polymer Degrudution und Stubility, Volume 66 tss~w 3, 1999. Thermogravimetric analysis coupled to Fourier transform infrared spectroscopy, TGA/FTIR, has been used to probe the degradation of several polymeric systems. These include poly( methyl methacrylate) in the presence of various additives, graft copolymers of acrylonitrile-butadiene-styrene and styrene-butadiene with sodium methacrylate and styrene with acrylonitrile, blends of styrene-butadiene block copolymers with poly(vinylphosphonic acid) and poly(vinylsulfonic acid), and cross-linked polyslyrenes. Additives may interact with poly(methyl methacrylate) by coordination to the carbonyl oxygen to a Lewis acid and the subsequent transfer of an electron from the polymer chain to the metal atom or by the formation of a radical which can trap the degrading radicals before they can undergo further degradation. When an inorganic char-former is graft copolymerized onto a polymer, there is a good correlation between TGA behavior in an inert atmosphere and thermal stability in air, but this is not true when the char is largely carbonific.
02000 Elsevier Science
Additives fiw Polvmers
Thermal degradation behavior and flammability of polyurethanes blended with poly(bispropoxyphosphazene) Wung, Pin-Sheng, Chiu, Wen- Yen, Chen, Leo- Wang, Denq, Bar-Long, Don, Trong-Ming, Chiu, Yie-Shun, National Taiwan Crniversity, Taipei, Taiwan in Polymer Degradation and Stabiliv, Vol66 No 3, 1999. Polyurethanes containing different amount of flame retardant, poly(bispropoxyphosphazene). were synthesized by a two-step polymerization.The thermal degradation behaviors of these polyurethanes were then studied by the thermal gravimetric analysis (TGA), TGA coupled with Fourier transform infrared analysis and elemental analysis. A limiting oxygen index was used to evaluate the flammability of these polyurethanes. For these modified polyurethanes under nitrogen, a two-stage thermal degradation behavior was observed. The first stage was caused by the degradation of hard segments. whereas the soft segments were responsible for the second-stage degradation. The thermal degradation activation energies were calculated by using Ozawa’s method. It was found that the addition of flame retardant caused a decrease of the activation energy in the first stage, but an increase in the second stage. which was probably due to the formation of a thermal stable structure. As for the flame retardany, the modified poly-urethanes have a higher char yield at 550$DGR@C, and a higher limiting oxygen index than the neat polyurethane.
Effect of coagent in reactive surface treatment for calcium carbonate filler in polypropylene Tabtinng, A., Vuubles, R.A., Mahidol Unitersif[)‘,Bangkok. Thailand in Plastics, Rubber and Composites, Vol28 Issue 1, 1999. Calcium carbonate as a filler for polypropylene has been modified with a reactive coupling system comprising acrylic acid (AA) and dicumyl peroxide(DCP), to promote coupling through grafting at the surface of the filler during melt compounding, in conjunction with trimethylolpropane trimethacrylate coagent (TMP) to limit degradation. The main effects and interactions between these three additives have been assessed via their influence upon selected characterization data. Inferences from
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