Vulcanization Characteristics and Dynamic Mechanical Behavior of Natural Rubber Reinforced with Silane Modified Silica

Abstract

Two silane coupling agents were used for hydrolysis-condensation reaction modification of nanosilica surfaces. The surface characteristics were analyzed using Fourier transform infrared spectroscopy (FTIR). The vulcanization kinetics of natural rubber (NR) + silica composites was studied and compared to behavior of the neat NR using differential scanning calorimetry (DSC) in the dynamic scan mode. Dynamic mechanical analysis (DMA) was performed to evaluate the effects of the surface modification. Activation energy E(a) values for the reaction are obtained. The presence of silica, modified or otherwise, inhibits the vulcanization reaction of NR. The neat silica containing system has the lowest cure rate index and the highest activation energy for the vulcanization reaction. The coupling agent with longer chains causes more swelling and moves the glass transition temperature T(g) downwards. Below the glass transition region, silica causes a lowering of the dynamic storage modulus G', a result of hindering the cure reaction. Above the glass transition, silica-again modified or otherwise-provides the expected reinforcement effect.

Antidegradation and reinforcement effects of phenyltrimethoxysilane- or N-[3-(trimethoxysilyl)propyl]aniline-modified silica particles in natural rubber composites

“…The scorch (t s2 ) and curing (t c90 ) times of the NR vulcanizates increased after filling with any of the different types of silica particles, which is because the silanol groups on the silica surface could react with the activator as well as the accelerator, resulting in the reduction of the number of active sulfurating agents for vulcanization [28,60]. It is important to note that the t s2 and t c90 values of Ce20V was longer than those of Ue20V, which again supported that the silica particles generated via a solegel reaction contained a lower density of silanol groups on the silica surface, in agreement with the EDS results (Section 3.1).…”

“…In order to solve this problem of silica aggregation, modification of the silica particles was evaluated in this research. Several kinds of organoalkoxysilane have previously been used to modify the silica surface, such as methyltriethoxysilane [18,19], vinyltriethoxysilane [19,20], phenyl triethoxysilane [20e25], phenyltrimethoxysilane (PhTMS) [22,26,27], 3-mercapto trimethoxysilane [18,28e31] and N- [3-(trimethoxysilyl)propyl]aniline (ATMS) [32e34] to improve the wettability [22,27,32,35e37], dispersibility [26,28,33,34,38] and selective adsorption [23e25,29e31]. The important factors that determine the ability of the modifying agent(s) to improve these properties of NR include the type and polarity of the modifying agent and the size of its substituted groups.…”

Ketahanan n-pentana dan sifat mekanis vulkanisat karet perapat dari campuran karet alam/akrilonitril-butadiena dengan kompatibiliser

“…Hasil rheometer tersebut menyajikan karakteristik pematangan pada masing-masing kompon yang meliputi; torsi maksimum (S max ) dan minimum (S min ), delta torsi (S max -S min ), waktu optimum vulkanisasi (t 90 ) dan indeks kecepatan reaksi (cure rate index/ CRI). CRI dihitung berdasarkan perbedaan t 90 dan waktu scorch vulkanisasi (t s2 ) dengan persamaan (1) berikut (Chonkaew et al, 2011 Pengujian sifat mekanis dan pengusangan vulkanisat Pengujian sifat mekanis vulkanisat karet perapat sesuai dengan SNI 7655:2010. Sifat mekanis vulkanisat yang diukur antara lain kekerasan, kuat tarik, perpanjangan putus dan pampatan tetap.…”

Microstructure, thermal stability, and mechanical properties of modified polycarbonate with polyolefin and silica nanoparticles

“…Silica (SiO 2 ) nanoparticles (NPs) have been widely incorporated into the polymer matrix to improve the mechanical and thermal properties of nanocomposites (NCs) structures as well as their surface resistances . Furthermore, the SiO 2 is an appropriate candidate as reinforcement particles to improve the fracture toughness properties of amorphous brittle polymers .…”