Influence of silica addition on the properties of epoxidised natural rubber/polyvinyl chloride composite membrane

Abstract

Flexible and porous epoxidised natural rubber (ENR)/polyvinyl chloride (PVC) membranes were prepared via phase inversion technique. The pore formation on ENR/PVC membranes was initiated with the introduction of inorganic particles (silica). Two types of silica, microsilica (microcrystalline silica powder) and nanosilica [generated from Tetraethoxysilane (TEOS)] were used. Effects of silica addition on the membrane structure are investigated by means of FTIR, SEM, TGA, and UTM. FTIR results showed the presence of signature peak of SiAOASi at 1102 and 1088 cm À1 for ENR/PVC/SiO 2 and ENR/PVC/TEOS membrane, respectively. Morphological studies showed that pores developed in ENR/PVC/TEOS membranes were more homogenous as compared to ENR/ PVC/SiO 2 membranes. Thermal and mechanical stability of the membranes improved with the incorporation of silica. ENR/PVC/SiO 2 membrane exhibited better mechanical and thermal properties as compared to ENR/PVC/TEOS membranes. CO 2 and N 2 gas permeation of silica-filled membranes increased with increasing silica content and the permeability of ENR/PVC/SiO 2 membrane toward N 2 and CO 2 gasses was higher than ENR/PVC/TEOS membrane.

Gas permeability of ENR/PVC membrane with the addition of inorganic fillers

“…This could be resulted as the fillers were leached out from the membranes during the phase inversion process. SiO 2 and MgO degrade at temperature higher than 600 °C, explaining the residues left and confirming that fillers addition resulted in the improvement of thermal stability of the polymer [11]. …”

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

“…However, the decrease in the mechanical properties of the nanocomposite at 3 phr nSiO 2 may be owing to the agglomeration of an excess nSiO 2 , leading to a poor dispersion of nSiO 2 in the ENR 40 matrix, a reduction in contact area between nSiO 2 and ENR 40, and also a filler-rubber interaction. However, the percentage retention in mechanical properties of all the ENR 40 nanocomposites was higher than that of the neat ENR 40, owing to a very high thermal resistance of the nSiO 2 [25,26].…”

“…The mol% epoxidation was calculated from (1) using data from the FT-IR peaks at 870 and 835 cm −1 [14,26].…”

“…The characteristic peaks of NR (Figure 1(a)) that appeared at 3037, 2850, 1660, 1450, 1375, and 835 cm −1 are assigned to the =C-H stretching, C-H stretching, C=C stretching, C-H bending of CH 2 , C-H bending of CH 3 , and =C-H bending, respectively [3,8,15,24]. The new characteristic peaks that appeared at 1240 and 870 cm −1 (Figure 1(b)) are assigned to the symmetric stretching and asymmetric stretching of epoxide ring, respectively [5,8,15,16,18,[24][25][26][27]. This confirmed the formation of epoxide or oxirane rings from the reaction of performic (generated in situ by the reaction of HCOOH and H 2 O 2 ) with the C=C on the NR molecules.…”

“…The peak at 1590 cm −1 is attributed to the bending vibration of the O-H bond in the adsorbed water molecules on nSiO 2 surfaces. The intensive peaks at about 1083 cm −1 , together with the less intensive peaks at 800 and 455 cm −1 , are attributed to the asymmetric stretching vibration, symmetric stretching vibration, and asymmetric bending vibration of Si-O-Si, respectively [24][25][26].…”