Effect of polydimethylsiloxane on oxidation of isotactic polypropylene

Монахова, Т. В.; Bogaevskaya, T. A.; Shlyapnikov, Yu.A.

doi:10.1016/s0141-3910(99)00057-9

Cited by 13 publications

(6 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…That is to say, with increasing PDMS content, the char increases, implying that the TPIU/PDMS copolymers with higher PDMS content are more thermally stable. This may be ascribed to the movement of free radicals into the inclusions of siloxane in TPIU/PDMS, and is consistent with the results of Monakhova et al, who reported that PDMS could delay the thermal oxidative aging of polypropylene.…”

Section: Resultssupporting

confidence: 91%

Investigations of Thermoplastic Poly(imide-urethanes) Flame-Retarded by Hydroxyl-Terminated Poly(dimethylsiloxane)

Tang

Yang

2014

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

Author: A series of novel intrinsically flame-retardant thermoplastic poly(imide-urethanes) (TPIUs) has been synthesized by 4,4′-diphenylmethane diisocyanate (MDI), poly(tetrahydrofuran) (PTMG), pyromellitic anhydride (PMDA), and hydroxyl-terminated poly(dimethylsiloxane) (PDMS) used as flame retardants. The obtained TPIU/PDMS exhibited good tensile strength and elongation at break. TPIU/PDMS has a higher thermal decomposition temperature than that of commercial PTMG−MDI−1,4-butanediol-based thermoplastic polyurethane (TPU) according to thermal gravimetric analysis. The total heat released and peak heat release rate of TPIU/12.4%PDMS were found to be lower than those of the pure TPIU by 8.0% and 26.3%, respectively, based on cone calorimeter testing. The condensed phase of TPIU/PDMS has been investigated by scanning electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive X-ray spectroscopy. The results indicate that the good flame retardancy of TPIU/PDMS can be attributed to thermally stable compounds with Si−O structures on the surface of its char layers.

show abstract

Section: Resultssupporting

confidence: 91%

Investigations of Thermoplastic Poly(imide-urethanes) Flame-Retarded by Hydroxyl-Terminated Poly(dimethylsiloxane)

Tang

Yang

2014

Ind. Eng. Chem. Res.

View full text Add to dashboard Cite

show abstract

“…In polymeric substances, there is a substantial increase in the role of the cage effect compared to that in their low‐molecular analogs, which results in a decrease in the yield of hydroperoxides from approximately 100% in hydrocarbons to 5–30% in polyolefins 1, 2. The irregularities in polymer chain arrangement in the polymers are stable and may be considered the second component dissolved in the polymeric substance 3.…”

mentioning

confidence: 99%

“…In polymers, these products are either neighboring groups of the same macromolecule or are present on neighboring molecules. In both cases, these groups are for a long time situated aside and interact with high probability, for example, as As a result, the yield of hydroperoxide per oxygen consumed decreases from 1 (100%) to a much smaller value and depends on oxygen concentration because the reaction with R• oxygen transforms these radicals into RO 2 •, which cannot decompose hydroperoxide groups 1, 2. It is more convenient to describe the process by the following scheme: The usual antioxidants, alkylated phenols and aromatic amines, more rapidly react with molecular oxygen than hydrocarbons and monomeric units of the polymer,1, 4 and the initiating step in the oxidation process becomes the interaction of the antioxidant with oxygen.…”

mentioning

confidence: 99%

Variation of inhibited oxidation parameters in polyethylene melting

Shlyapnikov

Kolesnikova

2006

J of Applied Polymer Sci

View full text Add to dashboard Cite

ABSTRACT:The oxidation of low-density polyethylene by molecular oxygen was studied in the temperature range 80 -210°C. In the curves of temperature dependence of several parameters of inhibited oxidation, breaks were observed at the melting temperature, near 110°C. At this temperature, the preexponential factor calculated from the temperature dependence of the rate constant of inhibitor consumption changed 105 times, sharply increasing at the transition from the polymer melt to the solid polymer. This indicated that an essential difference existed between the properties of the intercrystalline amorphous polymeric substance and the completely molten one. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 978 -981, 2006 Key words: polyethylene; melting point; antioxidants; phase behavior; crystallization Polymeric substances differ from their low-molecular analogs in several ways, the most essential for the investigation of polymer oxidation processes are the virtual zero pressure of the polymer vapors and the combination of an extremely low transition mobility of their macromolecules and a high vibrational mobility. Polymer melting proceeds in relatively wide temperature range in which the amorphous substance coexists with the crystalline one. It was interesting to compare this intercrystalline amorphous substance with completely the molten polymeric one.In this study, we used the simplest polymer, lowdensity polyethylene. As the method of investigation, we used the inhibited oxidation of the polymer in the temperature range 80 -210°C, which included the melting temperature of this polymer (110°C). The antioxidant was 2,2Ј-methylene-bis(4-methyl-6-methylcyclohexylphenol) (MBP). A relatively high molecular mass of this antioxidant decreased the role of antioxidant evaporation in the course of oxidation. On the other hand, difficulties in the quantitative extraction of this heavy antioxidant caused us to use an indirect method to calculate the rate constants of antioxidant consumption from the concentration dependence of the induction period of inhibited oxidation.In polymeric substances, there is a substantial increase in the role of the cage effect compared to that in their low-molecular analogs, which results in a decrease in the yield of hydroperoxides from approximately 100% in hydrocarbons to 5-30% in polyolefins.1,2 The irregularities in polymer chain arrangement in the polymers are stable and may be considered the second component dissolved in the polymeric substance. 3 In crystalline polymers below their melting temperatures, crystalline structures appear, whose contents increase with decreasing temperature. In some cases, these structures behave as free-radical traps (more correctly, traps for free valences). It was interesting to examine whether the intercrystalline amorphous substance differed in its properties from the same substance in a completely molten polymer.The main steps of hydrocarbon polymer oxidation are analogous to those of low-molecular hydrocarbons:However, in the second step, RO 2 ⅐ ϩ ...

show abstract

“…CPE can provide performance and cost advantages over other elastomer systems, such as polychloroprene, nitrile rubber (NBR), chlorosulfonated polyethylene, NBR/PVC blends 6. Blends of CPE and other polymers have received wide attention in the literature 7–13. The role of CPE as a compatibilizer has also been investigated 14.…”

Section: Introductionmentioning

confidence: 99%

A study on the compatibility and physical properties of chlorinated polyethylene rubber/nitrile rubber blends

Zhang

Chen

Gao

et al. 2010

J of Applied Polymer Sci

View full text Add to dashboard Cite

The miscibility and some physicomechanical characteristics of chlorinated polyethylene rubber (CPE) and nitrile rubber (NBR) blends have been investigated. Calculation of the heat of mixing, differential scanning calorimetry, and scanning electron microscopy analysis showed that CPE was miscible with NBR in all proportions. The cure and scorch times decreased with the increase in NBR content, whereas the maximum torque increased. The tensile strength, 100% modulus, elongation at break, tear strength, and compression set decreased with increasing of NBR content. After aging, hardness and tensile strength increased, and there was no drastic change in elongation at break on aging. The thermal aging resistance and the abrasion resistance of NBR are improved after blending with CPE, but the oil resistance decreased.

show abstract

Effect of polydimethylsiloxane on oxidation of isotactic polypropylene

Cited by 13 publications

References 2 publications

Investigations of Thermoplastic Poly(imide-urethanes) Flame-Retarded by Hydroxyl-Terminated Poly(dimethylsiloxane)

Investigations of Thermoplastic Poly(imide-urethanes) Flame-Retarded by Hydroxyl-Terminated Poly(dimethylsiloxane)

Variation of inhibited oxidation parameters in polyethylene melting

A study on the compatibility and physical properties of chlorinated polyethylene rubber/nitrile rubber blends

Contact Info

Product

Resources

About