Effect of Compound Formulation and Processing Conditions on Properties of Extruded EPDM and NR/EPDM Foams

Lewis, Chonlada; Rodlum, Y.; Misaen, B.; Changchum, Sarote; Sims, G. L. A.

doi:10.1177/026248930302200103

Cited by 12 publications

(12 citation statements)

References 5 publications

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“…Figure 4 shows that it is detrimental to the growth of cells at 180°C because the rate of the curing curve is rapid enough to compete the vulcanization. Therefore, the relationship of the rate of POE vulcanization and blowing agent decomposition is a key factor in producing foam materials, and this is similar to the results of some reports 28–30. According to integrated factors, 170°C is the most appropriate temperature for foaming.…”

Section: Resultssupporting

confidence: 71%

Preparation of polyethylene–octene elastomer foams by compression molding

Mao

2008

J of Applied Polymer Sci

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To produce polyethylene-octene elastomer foams with compression molding, the influences of various activators on the thermal decomposition temperature of the chemical blowing agent azodicarbonamide were investigated with thermogravimetric analysis, which showed that the decomposition temperature of azodicarbonamide could be effectively reduced by the addition of zinc oxide/ zinc stearate. The results of a moving die rheometer suggested that the vulcanization and blowing curves were influenced by the content of azodicarbonamide and temperature, and the optimum temperature was about 1708C. The morphology and physical properties of the microcellular polyethylene-octene elastomer were studied. The results indicated that the amount of azodicarbonamide and the processing temperature played important roles in the cell morphology and physical properties of polyethylene-octene elastomer foams.

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Section: Resultssupporting

confidence: 71%

Preparation of polyethylene–octene elastomer foams by compression molding

Mao

2008

J of Applied Polymer Sci

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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%

“…To balance the reaction rate of blowing agent decomposition and compound vulcanization, many work had focused on the two aspects, i.e., compound formulation and vulcanization process , which could enhance the modulus of matrix to be strong enough to withstand the gas pressure when the chemical blowing agents decomposed in the initial stage. Furthermore, previous studies showed the compounds with various blowing agents and cure accelerators was extremely important to the production of sponges with desired morphology. In addition, foam processibility could be improved by adjusting the foaming process, which utilizes two‐stage compression molding that refers to the slow curing process in which no CBA decomposed occurs in lower temperature and then the a mass of CBA decomposed at higher temperature.…”

Section: Introductionmentioning

confidence: 99%

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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“…Regardless of the process employed, the successful production of foamed articles requires control of the entire cure–expansion operation,6, 7 which depends on a very delicate balance of two simultaneously occurring reactions—–the vulcanization of the rubber and the decomposition of the blowing agent. In fact, to balance the reaction rate of decomposition and vulcanization, previous studies have shown the compound8–10 of various blowing agents and cure accelerators is extremely important to the production of sponges with desired morphology. Because of the very complex systems and that various reactions interfere with each other strongly, it is very difficult to understand the two kinds of chemical reactions which take place simultaneously in the blowing process.…”

Section: Introductionmentioning

confidence: 99%

“…It is well known that EPDM has chemical stability, good ageing resistance, high load capacity, and high resistance to breakdown during mechanical operations. Now EPDM finds increasing acceptance for producing cellular sections3, 11, 12 The effects of the EPDM grade, blowing agent type, composition of EPDM blend, and processing conditions on the cell structure and the physical properties of the resultant EPDM foams were investigated 9, 10, 13–15. However for EPDM, which is a slow vulcanizing rubber, the choice of type of vulcanization systems in combination with the blowing agents to produce the optimization of the cell structure and surface appearance is difficult aspect of the compounding technology for EPDM expansion.…”

Section: Introductionmentioning

confidence: 99%

Rheological properties and foam processibility of precured EPDM

Wang

Peng

Zhang

et al. 2006

J of Applied Polymer Sci

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EPDM foam was prepared by dynamically vulcanizing EPDM compound in a HAAKE rheometer firstly, then mixing the partially precured EPDM compound with a blowing agent and a sulfur vulcanizing system on a two roll mill. The compound was extruded through a cold feed extruder, and the extrudate was foamed in a circulating hot air oven. EPDM compound was vulcanized partly in the HAAKE rheometer, the final torque increases with increasing sulfur content. Rheological measurement shows the dynamic storage modulus, the loss modulus, and the complex viscosity of precured EPDM compound increase with increasing sulfur content. Then the partially precured EPDM compound was compounded with a blowing agent and a sulfur vulcanizing systems, Rheometric measurement shows that the rate of vulcanization of partially precured EPDM compound is not affected by the precure. The blowing results show that the foam processibility could be improved and the expansion ratio increases in the same processing condition for optimum partially precured EPDM compound, which indicates the optimum crosslink density for EPDM could enhance the efficiency of blowing agent AC. SEM shows that the foam articles have a closed-cell structure with few open cells, and the large cells inlay among the small cells.

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Effect of Compound Formulation and Processing Conditions on Properties of Extruded EPDM and NR/EPDM Foams

Cited by 12 publications

References 5 publications

Preparation of polyethylene–octene elastomer foams by compression molding

Preparation of polyethylene–octene elastomer foams by compression molding

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

Rheological properties and foam processibility of precured EPDM

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