Rheological properties and foam processibility of precured EPDM

Wang, Bi‐Qin; Peng, Zonglin; Zhang, Yong; Zhang, Yinxi

doi:10.1002/app.24059

Cited by 14 publications

(11 citation statements)

References 20 publications

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“…The results demonstrated that the optimum precured degree (30%) for BR/SBR/NR gross rubber could improve its foam processibility and enhance the efficiency of OBSH, which was in agreement with the results revealed by the cure and foaming characteristic. This is similar to the literatures about foaming , in which they prepared rubber foams by adjusting the rate of rubber vulcanization and blowing agent decomposition simultaneously. Although the ways are different from each other, those previous studies showed the initial modulus of the compound is the very important factor for foaming when the blowing agent decomposed at the early stage.…”

Section: Resultssupporting

confidence: 84%

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Effect of precured degrees on morphology, thermal, and mechanical properties of BR/SBR/NR foams

2013

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The ternary composites of 1,4-cis polybutadiene rubbers (BR), styrene-butadiene rubber (SBR), and natural rubber (NR) foams containing chemical blowing agents Oxybis (benzene sulfonyl) hydrazide (OBSH) were prepared by two-stage compression molding technique with various precured degrees. Foam force rheometer indicated that the cure rate was match with foaming rate at precured degree of 30%, which the time of the maximum foaming rate was earlier only 14 s than that of the maximum cure rate. SEM presented that the number of cell was denser at precured degree of 30% than those with other precured degrees. The average cell size declined, cell wall thickness became thicker, and cell distribution became narrower just as precured degree was increasing. The results of crosslinking density was measured by equilibrium swelling technique in good agreement with that of magnetism resonance crosslinking density spectrometer measurement, which crosslinking density was increased as precured degrees increased. Differential scanning calorimeter showed that each curve exhibits two steps in heat capacity for BR/SBR/NR foams. With further increase of precured degrees, the two groups of T g s were all shift to the higher temperature, and the area of the melting peak decreased gradually between 2208C and 2408C. TGA results demonstrated that BR/SBR/NR foams with various precured degrees obtained better thermal stability than those of non-precured foams. The high density of polymeric foams exhibits the high mechanical properties such as tensile strength, tear strength, and elongation at break. The inflection points of density, cell density, and hardness were all appeared at precured degree of 30%. POLYM. COMPOS., 34:849-859, 2013. ª

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Section: Resultssupporting

confidence: 84%

“…Finally, the curing agent S was added. Then, the compounds were discharged from the two‐roll mill and stored at room temperature for 24 h before foaming . The cure characteristics of vulcanizates were determined on a foam force rheometer.…”

Section: Methodsmentioning

confidence: 99%

Effect of precured degrees on morphology, thermal, and mechanical properties of BR/SBR/NR foams

2013

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“…In fact, the crosslinking rate of the rubber melt should be synchronous with the decomposing rate of the blowing agent in order to obtain excellent properties . Moreover, additives to silicone foams, called filler, can add stiffness, and reduce the overall cost …”

Section: Introductionmentioning

confidence: 99%

“…[11,12] Moreover, additives to silicone foams, called filler, can add stiffness, and reduce the overall cost. [14][15][16] Several parameters may have a major effect on the foam properties. Different combinations of processing parameters, rheological, and morphological properties of the formulation can modify cell structure.…”

Section: Introductionmentioning

confidence: 99%

Study of the Coalescence Mechanisms During Silicone Foaming

Jawhar

Blanc

Chaumont

et al. 2013

Macromol. Mater. Eng.

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International audienceA foam sample is assumed to be a set of bubbles embedded into a polymeric matrix with an initial gas overpressure. Silicon foams are produced by a competition between two reactions involving the hydrogenosilane functions carried by the polymer precursor: the first reaction generates gas (initiating cell formation) while the other one, hydrosilylation, well known and controlled in silicon, leads to the crosslinking of the rising foam. Thus, obtaining enhanced foam properties requires a good balance between two reactions, crosslinking and gas generation. On the other hand, the final characteristics of the foam (porosity, bulk density, etc.) largely depend on the rheology of the mix (appropriate elongational properties) as well as the added fillers. Nucleation and cell growth were carried out under optical microscopy. The experiments show that the main phenomenon controlling cell growth is bubble coalescence. Due to the surface effects and the viscoelastic properties, bubbles approach from each other and get deformed giving birth to an intermediate shape before reaching their final geometry. Many parameters have direct effect on foam properties. In fact, dissolved gas in formulae as well as the air introduced during manual mixing, reduce the skin effect and guarantee a homogeneous cell size distribution and a better foam structure. Other factors have also been studied in order to render size distribution more homogeneous and improve certain properties

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“…This effect is also known as the cure rate index (CRI) and is calculated with the following relationship:

CRI = 100 / t_{90} - t_{s}_{2}

where t 90 is the final vulcanization time and t s 2 is the scorch time of the samples, as elaborated in Figure . The scorch time ( t s 2 ) is the time for the premature vulcanization of the polymer up to 2%, and t s 1 is the time between the closure of the dies and the increase in torque up to 1 dN m. Figure also shows a descending trend of the scorch time with increasing carbon black concentration in the EPDM rubber due to viscosity elevation of the composite specimen …”

Section: Resultsmentioning

confidence: 97%

Structural, viscoelastic, and vulcanization study of sponge ethylene–propylene–diene monomer composites with various carbon black loadings

Bashir

Iqbal

Shahid

et al. 2013

J of Applied Polymer Sci

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In this article, we report the effect of various carbon nanoparticle concentrations on the structural, curing, tan δ, viscosity variation during vulcanization, thermal, and mechanical characteristics of ethylene–propylene–diene monomer polymer sponge composites. The purpose of this study was to develop high‐strength, foamy‐structure polymer composites with an optimum filler to matrix ratio for advanced engineering applications. We observed that the structural, vulcanization, viscoelastic, and mechanical properties of the fabricated composites were efficiently influenced with the progressive addition of carbon content in the rubber matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39423.

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Rheological properties and foam processibility of precured EPDM

Cited by 14 publications

References 20 publications

Effect of precured degrees on morphology, thermal, and mechanical properties of BR/SBR/NR foams

Effect of precured degrees on morphology, thermal, and mechanical properties of BR/SBR/NR foams

Study of the Coalescence Mechanisms During Silicone Foaming

Structural, viscoelastic, and vulcanization study of sponge ethylene–propylene–diene monomer composites with various carbon black loadings

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