Comparative Properties of Silica- And Carbon Black-Reinforced Natural Rubber in the Presence of Epoxidized Low Molecular Weight Polymer

Abstract

This work investigates the effect of epoxidized low molecular weight natural rubber (ELMWNR) in silica- and carbon black-filled natural rubber (NR) compounds on processing and mechanical and dynamic mechanical properties. The ELMWNRs with different mol% epoxide content were prepared from depolymerization of epoxidized NR using periodic acid in latex state to have a molecular weight in a range of 50 000–60 000 g/mol. Their chemical structures and actual mol% of epoxide were analyzed by 1H NMR. The ELMWNRs were added to the filled NR compounds as compatibilizers at varying loadings from 0 to 15 phr. The addition of ELMWNR decreases compound viscosity and the Payne effect, that is, filler–filler interaction, of the silica-filled compound. In the silica–silane compound and the compound with 28 mol% epoxide (ELMWNR-28), the compound viscosities are comparable. The optimal mechanical properties of silica-filled vulcanizates are obtained at the ELMWNR-28 loading of 10 phr. In contrast, the addition of ELMWNR to a carbon black-filled compound shows only a plasticizing effect. The incorporation of ELMWNR into NR compounds introduces a second glass transition temperature and affects their dynamic mechanical properties. Higher epoxide contents lead to higher loss tangent values of the rubber vulcanizates in the range of the normal service temperature of a tire.

The behavior of natural rubber–epoxidized natural rubber–silica composites based on wet masterbatch technique

“…10,12 Although its application has been limited by its high cost and poor aging properties, [13][14][15] there are still reports of ENR being employed as a compatibilizer for silica-filled rubber. 10,12,16,17 The results show a substantial improvement in silica dispersion and mechanical properties, but still lower than when using Si-69. As a matter of fact, the interfacial bonding between ENR and silica was mainly achieved by long-term dry mixing under high temperature.…”

Use of TBzTD as Noncarcinogenic Accelerator for ENR/SiO2 Nanocomposites: Cured Characteristics, Mechanical Properties, Thermal Behaviors, and Oil Resistance

“…In addition, all the g values of the vulcanized samples followed the same trend as those of the unvulcanized samples (Table 1). Among the nanocomposites, the ENR 40 filled with 2 phr nSiO 2 exhibited the lowest g owing to a better dispersion of nSiO 2 that caused a decrease of the ENR 40 being trapped within the nSiO 2 network and so resulted in a higher mobility of the rubber chain segments; hence g decreased [30,31]. tan max (height of tan peak) values are also listed in Table 1.…”

Silica nanoparticles reinforced natural rubber latex composites: The effects of silica dimension and polydispersity on performance

“…Meanwhile, it was observed a decrease in viscosity of compounds after adding TESPT into silica. This may be due to the plasticizing effect induced by the silane coupling agent and the chemical reaction between TESPT and silanol group on the silica surface …”

“…In the field of rubber processing, as being the largest representative, natural rubber (NR) is usually required to be reinforced with fillers to satisfy necessary strengths and mechanical properties for most applications . The commonly used reinforcing fillers in the current industry are carbon black and silica.…”