Abstract:Abstract. The photo-oxidation of ethylene propylene diene monomer (EPDM)/ layered double hydroxide (LDH) composites as well as EPDM/LDH with stabilizers is studied under accelerated UV irradiation (λ ≥ 290 nm) at 60°C for different time intervals. The development of functional groups during oxidation was monitored by FT-IR spectroscopy. The photodegradation of the pristine polymer and composites take place and the increase in hydroxyl and carbonyl groups with irradiation times, was estimated. EPDM filled LDH s… Show more
“…Ionic elastomers based on carboxylated nitrile rubber (XNBR) and magnesium aluminum layered double hydroxide (hydrotalcite) [5][6][7][8][9], acrylonitrile-butadiene rubber (NBR) [10], chloroprene rubber (CR) [11], silicone rubber (SR) [12,13], and polyurethane PU [14][15][16] and solution styrenebutadiene rubber (SSBR) [17]. However, in the literature, there is no information on the impact of high loadings of unmodified magnesium aluminum layered double hydroxide used as a filler and a curing agent on the crosslinking process in XNBR.…”
Abstract. The presence of carboxyl groups in carboxylated nitrile butadiene rubber (XNBR) allows it to be cured with different agents. This study considers the effect of crosslinking of XNBR by magnesium aluminum layered double hydroxide (MgAl-LDH), known also as hydrotalcite (HT), on rheometric, mechano-dynamical and barrier properties. Results of XNBR/HT composites containing various HT loadings without conventional curatives are compared with XNBR compound crosslinked with commonly used zinc oxide. Hydrotalcite acts as an effective crosslinking agent for XNBR, as is particularly evident from rheometric and Fourier transform infrared spectroscopy (FTIR) studies. The existence of ionic crosslinks was also detected by dynamic mechanical analysis (DMA) of the resulting composites. DMA studies revealed that the XNBR/HT composites exhibited two transitions -one occurring at low temperature is associated to the T g of elastomer and the second at high temperature corresponds to the ionic transition temperature T i . Simultaneous application of HT as a curing agent and a filler may deliver not only environmentally friendly, zinc oxide-free rubber product but also ionic elastomer composite with excellent mechanical, barrier and transparent properties.
“…Ionic elastomers based on carboxylated nitrile rubber (XNBR) and magnesium aluminum layered double hydroxide (hydrotalcite) [5][6][7][8][9], acrylonitrile-butadiene rubber (NBR) [10], chloroprene rubber (CR) [11], silicone rubber (SR) [12,13], and polyurethane PU [14][15][16] and solution styrenebutadiene rubber (SSBR) [17]. However, in the literature, there is no information on the impact of high loadings of unmodified magnesium aluminum layered double hydroxide used as a filler and a curing agent on the crosslinking process in XNBR.…”
Abstract. The presence of carboxyl groups in carboxylated nitrile butadiene rubber (XNBR) allows it to be cured with different agents. This study considers the effect of crosslinking of XNBR by magnesium aluminum layered double hydroxide (MgAl-LDH), known also as hydrotalcite (HT), on rheometric, mechano-dynamical and barrier properties. Results of XNBR/HT composites containing various HT loadings without conventional curatives are compared with XNBR compound crosslinked with commonly used zinc oxide. Hydrotalcite acts as an effective crosslinking agent for XNBR, as is particularly evident from rheometric and Fourier transform infrared spectroscopy (FTIR) studies. The existence of ionic crosslinks was also detected by dynamic mechanical analysis (DMA) of the resulting composites. DMA studies revealed that the XNBR/HT composites exhibited two transitions -one occurring at low temperature is associated to the T g of elastomer and the second at high temperature corresponds to the ionic transition temperature T i . Simultaneous application of HT as a curing agent and a filler may deliver not only environmentally friendly, zinc oxide-free rubber product but also ionic elastomer composite with excellent mechanical, barrier and transparent properties.
“…62 Pristine polymer was more stable but the presence of hydrotalcite was preferential if material was to operate exposed to UV radiation in an acidic environment. 62 Combination of phosphites and hydrotalcite gives better stability to poly(ethylene terephthalate).…”
Section: Acid Neutralizationmentioning
confidence: 98%
“…62 Pristine polymer was more stable but the presence of hydrotalcite was preferential if material was to operate exposed to UV radiation in an acidic environment. 62 Combination of phosphites and hydrotalcite gives better stability to poly(ethylene terephthalate). 63 It should be noticed that phosphites are also acid scavengers, but they are not hydrolytically stable, and most likely hydrotalcite prevents their hydrolysis.…”
Section: Acid Neutralizationmentioning
confidence: 98%
“…61 Hydrotalcite acid-scavenging mechanism is presented in Figure 3.17. 62 In addition to hydrotalcite, calcium and zinc stearates are known as popular acid scavengers.…”
“…The photooxidation of EPDM/LDH composites as well as EPDM/LDH with stabilizers was studied under accelerated UV irradiation [116]. EPDM filled LDH showed higher degradation rate than pristine EPDM.…”
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