Influence of different components in a TPV PP/EPDM based with low hardness

Abstract

Thermoplastic vulcanizates (TPVs) are a class of polymeric material obtained by dynamic vulcanization of an elastomer in a melted thermoplastic matrix. This work intend to evaluate different variables in the production of low hardness TPVs made of polypropylene (PP) and ethylene propylene rubber (EPDM), as well the optimization of the variables looking for TPVs with improved performance. In the Study I the influence of PP crystallinity were evaluated, in the Study II the effects of different amounts of dicumyl peroxide (DCP) were evaluated and in the Study III the amount of the phenolic resin were evaluated. This extended abstract presents, in a more detailed way, the results considering the curative phenolic resin content (Study III). The others results and discussions are briefly described in the results and discussions section. The compounds were obtained in a closed mixing chamber and their processability properties, swelling, hardness and tensile strength were evaluated. With the results obtained were possible to evaluate the influence of different ingredients in the TPVs properties. The results were discussed and presented looking for a better understanding of the influence of this variable in the final product, as well the correlation between then.

Cross-linking of rubber in the presence of multi-functional cross-linking aids via thermoreversible Diels-Alder chemistry

“…At constant PK-FU content the cross-link density increases with the degree of furan-functionalization of PK (and corresponding equivalent of BM). Similar behavior has been reported for rubber-based systems compounded with phenolic resins, either interpenetrating [30][31][32] or chemically bonded to the rubber matrix [33][34][35][36][37][38]. PK-BU is not able to form any DA adduct and, indeed, the reference blends with PK-BU show the lowest apparent cross-link densities, which are…”

“…During the vulcanization stage, the phenolic resins are cured independently from the rubber, forming an interpenetrating polymer network [30][31][32]. Depending on the structure of the phenolic resins, covalent bonds can be formed between the two networks and, thus, phenolic resins can also be viewed as rigid cross-linking agents [33][34][35][36][37][38].…”

Elasto-Plastic Materials based on EPDM Rubber, LDPE, Plasticized Starch and OMMT

“…It is observed that the values of the torque in this part are higher in the mixture containing the OMMT nanofiller due to its high strengthening effect. For the sample containing the vulcanization resin, due to the dynamic crosslinking of the elastomer in the LDPE melt, an even greater increase in the torque can be observed, which may indicate an increase in the viscosity of the mixtures due to the crosslinking reactions [15]. In this stage corresponding to the homogenization of the mixtures (Figure 1c), due to the shear forces, the temperature increases exponentially until minimum torque is reached.…”

“…An increase in hardness can be observed due to the reinforcing effect of the nanofiller -the hardness value increases from 33°ShD (mixture B) to 38°ShD (mixture C) by adding 3 parts per 100 parts of rubber (phr) of OMMT nanofiller. Comparing the hardness values of mixtures A, B, C, and D, an increase in hardness can be seen with the increase in the amount of phenolic crosslinking resin, indicating that the crosslinking of the EPDM elastomer in the LDPE melt was achieved with the formation of a three-dimensional network that led to an additional reinforcement of the samples [15]. Values of elasticity or resilience (Schob) are of 16-22% and their decrease (of about 10-27%) is observed when the percentage of elastomer in the mixture decreases, as well as an improvement by dynamic crosslinking (of about 17%) of the elastomer (Figure 3).…”

“…Values of elasticity or resilience (Schob) are of 16-22% and their decrease (of about 10-27%) is observed when the percentage of elastomer in the mixture decreases, as well as an improvement by dynamic crosslinking (of about 17%) of the elastomer (Figure 3). these characteristics are improved by increasing the amount of crosslinking agent as a result of increasing the degree of crosslinking of the elastomer [15], as well as by adding OMMT which leads to the formation of a nanocomposite by intercalating the polymer melt between the layers of OMMT [16].…”