scholarly journals Thermal analysis of halogenated rubber cured with a new cross-linking system

2019 ◽  
Vol 138 (6) ◽  
pp. 4395-4405 ◽  
Author(s):  
Anna Dziemidkiewicz ◽  
Magdalena Maciejewska ◽  
Martyna Pingot

Abstract The aim of this work was to examine the influence of new curing agents proposed for brominated butyl rubber (BIIR) on the cross-linking process of rubber compounds and the thermal behavior of the vulcanizates. Rubber blends that were filled with carbon black and contained acetylacetonates of different transition metals in the presence of triethanolamine (TEOA) as new cross-linking agents were prepared. The performed studies showed that metal acetylacetonates (Me(acac)) are effective cross-linking agents for BIIR, which was confirmed by high values of the torque increment (∆M) and significant cross-linking degree of the vulcanizates (α(T)). The most active curing agent seems to be iron acetylacetonate (Fe(acac)). Its application results in a shorter optimal vulcanization time, lower onset vulcanization temperature and similar vulcanization enthalpy compared to the BIIR cured with a sulfur curing system. The BIIR vulcanizates cured with Me(acac) reveal good mechanical properties with tensile strengths in the range of 9–14 MPa and better damping properties comparing to the sulfur-cured rubber. The proposed curing agents do not significantly affect the thermal stability of the BIIR vulcanizates.


Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1374 ◽  
Author(s):  
Tuo Lei ◽  
Yong-Wang Zhang ◽  
Dong-Liang Kuang ◽  
Yong-Rui Yang

To improve the energy dissipation capacity of rubber isolation bearings, it is important to find a new rubber material with good applicability and high damping properties. Two types of blends were prepared using nitrile rubber (NBR), brominated butyl rubber (BIIR) and ethylene-vinyl acetate copolymer (EVA): NBR/BIIR and NBR/BIIR/EVA. The vulcanization, mechanical and damping properties of the blends were analyzed. The results show that both blends exhibit excellent vulcanization plateaus and mechanical properties. For NBR/BIIR, as the BIIR content increases, the complementary effects of NBR and BIIR afforded by blending are enhanced. Two damping peaks appeared in the tanδ-T curve and shifted toward lower and higher temperatures, respectively, which clearly widened the effective damping temperature range. However, the damping value in the valley of the tanδ-T curve was as low as 0.39. For NBR/BIIR/EVA, the addition of EVA greatly increased damping in the valley of the tanδ-T curve to approximately 0.54. EVA was observed to be the optimal polymer for improving the compatibility of the NBR/BIIR blend. Moreover, hot air thermal aging tests showed that both blends demonstrated good stability.



2019 ◽  
Vol 31 (11) ◽  
pp. 2537-2542
Author(s):  
A. Sharma ◽  
S.K. Sharma ◽  
A. Rani

Polyethylene glycol based polyurethane polymer and its fly ash reinforced polyurethane composite were prepared by optimizing the concentration ratio of binders, cross linking agents and curing agents. The components ratio of cross linking agents with the same hydroxyl functionalities i.e. 1,4-butane diol and 1,1,1-trimethylol propane affects the mechanical properties of polymer. The extent of polymerization of polyurethane matrix and fly ash reinforced polyurethane composite was found to be independent of the component ratio of cross linking agents. PEG based polyurethane polymer and their fly ash-reinforced composite can be synthesized at particular ratio by mass of cross linking agents i.e. 0.5 keeping constant w/w ratio 3:2 of binders and curing agents. Effect of w/w ratio variation of cross linking agents on the extent of polymerization has been studied through SEM technique. Cross linking agents, curing agents and polyurethane composite have been characterized by IR spectra. Effect of w/w ratio variation of binary components 1,4-butane diol and 1,1,1-trimethylol propane of cross linking agents on the mechanical properties of fly ash-reinforced polyurethane composite has been studied by evaluating tensile strength and Young modulus of composite material by universal testing machine. Hardness of fly ash-reinforced polyurethane composite with different ratio of 1,4-butane diol and 1,1,1-trimethylol propane of cross linking agents was evaluated by durometer



2011 ◽  
Vol 13 ◽  
pp. 27-32 ◽  
Author(s):  
Zdenĕk Jonšta ◽  
Pavel Koštial ◽  
Ivan Ružiak ◽  
Peter Jonšta ◽  
J. Jurčiová ◽  
...  

In the paper we present measurements of transport physical parameters such as thermal conductivity, diffusivity and specific heat capacity and dc electrical conductivity as well as the mechanical values E*, tg δ for rubber compounds filled by different ratio of silica - carbon black fillers. From presented results it is possible to see that proper filler concentration (rubber blend - silica - carbon black) rising all thermal parameters as well as mechanical properties represented by complex Young’s modulus and so, maintains the good mechanical parameters of the blend and finally it also lowers the electrical resistance. All trends are favourable for the improvement of useful rubber blends properties.



2015 ◽  
Vol 1110 ◽  
pp. 69-72
Author(s):  
Fu Ke Wang ◽  
Chao Bin He

The dispersion and exfoliation of graphene oxides in polymer matrix remains a challenge for graphene oxides based epoxy nanocomposites fabrication. In the present paper, we reported a simple and facile solvent exchange technique to successfully transfer graphene oxides (GOs) from aqueous solution to ethanol. In addition, we found that GO dispersion in epoxy resins was affected by the curing agents. Good dispersion of GOs in epoxy resin together with enhanced thermal and mechanical properties were observed when epoxy was cured with aliphatic curing agents. For aromatic curing agent, high loading of GOs leaded to GOs aggregation, but well dispersed GOs was observed at low loading of GOs. Especially, a 12 °C increase of glass transition temperature of the epoxy resin was observed with only 0.1 wt% GOs was added to the epoxy resin.



Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1324
Author(s):  
Anna Rudawska ◽  
Mariaenrica Frigione

The effects of aging exposures to three non-saline aqueous environments on the compressive mechanical properties of a calcium carbonate-filled bisphenolic epoxy adhesive, cold-cured with the addition of two curing agents suitable for the cure at ambient temperature (i.e., Mannich base and triethylenetetramine), were assessed. The amount of the added filler (CaCO3) varied from 1 to 3 g per 100 g of resin; the immersion times in each of the selected medium varied from 1 to 10 months. It was found that the mechanical properties measured in compression mode on cylindrical specimens of unfilled and CaCO3-loaded epoxy were scarcely influenced by the kind of curing agent employed; only the compressive modulus was limitedly affected by this parameter. Referring to the behavior when aged in water, the CaCO3-filled epoxies displayed noticeable growths in modulus, small reductions in strength, and limited variations in strain, with a certain influence of the exposure time, especially when comparing the properties at the lowest time with those at medium–long times. On the basis of the results of statistical MANOVA analysis, it can be concluded that among the compositional factors (i.e., the type of curing agent employed to cure the epoxy compounds and the micro-filler content), only the amount of CaCO3 filler significantly affects the compressive modulus.



1982 ◽  
Vol 55 (5) ◽  
pp. 1328-1340 ◽  
Author(s):  
L. F. Ramos-DeValle ◽  
R. R. Ramírez

Abstract An experimental study of the mixing and final mechanical properties of blends of guayule rubber with polyolefins was carried out. It was found that (1) variation in total mixing time during blend preparation produced only minor differences in maximum tensile properties; (2) tensile properties of the blends approach those of the plastic at GR concentrations of 50% and lower, those of the rubber at GR concentrations of 70% and higher; (3) tensile properties of partially crosslinked blends improve if the addition of DCP is effected after partial mixing of the pure homopolymers; (4) the partial cross-linking of the blend exerts a strong beneficial influence on the mechanical properties; (5) the addition of carbon black exerts little influence on the mechanical properties of the blend. It can be suggested that, at 60% GR, both polymers (GR and HDPE) show the same tendency to form the continuous or dominant phase. Above 60%, the rubber tends to be the dominant phase, and below 60% the plastic tends to be the dominant phase. The mechanical properties of partially crosslinked GR-HDPE blends are comparable with those of similar commercially available products. This suggests a further alternative in the commercialization of natural guayule rubber, namely, thermoplastic rubbers.



2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Mirosława Prochoń ◽  
Anita Przepiórkowska ◽  
Yves-Herve Tshela Ntumba

The current investigation treats about the influence of waste fodder potato proteins (WFPP) recovered from the starch industry on the mechanical-properties of carboxylated acrylonitrile-butadiene rubber (XNBR). WFPP were characterized and used as a filler of the above mentioned XNBR rubber without or after blending with zinc oxide. The obtained rubber compounds were cured, and mechanical properties such as tensile strength, hardness, and cross-linking density were investigated. It was found that the introduction of WFPP previously blended with zinc oxide into rubber compound increases the cross-linking density of the obtained composites, compared with the vulcanizate without protein, which in turn increases the mechanical properties of the obtained vulcanizates. That occurs thanks to the formation of ion nodes, as testified by equilibrium swelling. The introduction of WFPP into the elastomer matrix also increases the susceptibility of the elastomer to biodecomposition.



2014 ◽  
Vol 1053 ◽  
pp. 257-262
Author(s):  
Mei Li ◽  
Xiang Yu Zhao ◽  
Wei Shao ◽  
Chuan Bao Ma ◽  
Rui Xue Zheng ◽  
...  

An epoxy adhesive and its curing agent are tested using differential scaning calorimetry under different atmospheres and after different exposure times to natural air to analyze its thermal properties. The results show that after the pure epoxy, the curing agent and the adhesive mixture of them are exposed in natural air for different period of time, all show different levels of decline in thermal stability and more complicated reactions when tested in the DSC and TGA in O2 and air, while the thermal properties remain stable when they are tested in an inert gas like N2. And according to the mechanical property tests and SEM results, the mechanical properties of the adhesive mixture in N2 are better than that in air. The results indicate that inert gas can protect the property of this kind of adhesive and thus increase its bond strength.



2014 ◽  
Vol 912-914 ◽  
pp. 390-394 ◽  
Author(s):  
Yan Fang Zhao ◽  
Dan Liu ◽  
Shuang Quan Liao ◽  
Xiao Xue Liao ◽  
Sheng Bo Lin

The research on the mechanical properties and thermal stability of the natural rubber filled with different dosage of Zinc oxide (ZnO). The results showed that with the increase of the content of the ZnO, the tensile strength first increased, then decreased the, but the tear strength showed a trend of increase,the thermal stability had improved; When the amount of ZnO added was 9, damping performance was better.



2011 ◽  
Vol 311-313 ◽  
pp. 1128-1131
Author(s):  
Yan Qin ◽  
Jin Rong Jia ◽  
Zhi Xiong Huang

A new two-component polyurethane adhesive was prepared with castor oil used as main agent and castor oil modified TDI used as curing agent.The effect of castor oil on the mechanical properties, adhesion properties and thermal stability of this adhesive were studied.This paper show us that TDI could be used as curing agent after modification. When the NCO/OH in curing agent and main agent:curing agent were 1.6 and 3:5 respectively, high performance adhesive was obtained.



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