Swapan Kumar Mandal

Impact of surface modification on the properties of sol–gel synthesized nanotitanium dioxide (TiO2)-based styrene butadiene rubber (SBR) nanocomposites

AbstractThe present paper provides a modern route to reinforce styrene butadiene rubber (SBR) nanocomposites by the proper utilization of sol–gel synthesized nanotitanium dioxide (TiO2). In order to achieve proper dispersion within the SBR matrix, the surface of nano-TiO2 is modified by cationic surfactants cetyltrimethylammonium bromide (CTAB) and tetraethylammonium bromide (TEAB). The surface modification of nano-TiO2 is characterized by Fourier transform infrared spectra and field emission scanning electron microscopy. The result reveals that after surface modification, sol–gel derived nano-TiO2 is much more efficient to improve the cure, mechanical and thermal properties of SBR nanocomposites in comparison with unmodified nano-TiO2. This is due to the excellent dispersion of modified nano-TiO2 within the SBR matrix, leading to the good compatibility between SBR and nano-TiO2, as confirmed from morphological analysis. Further, CTAB-treated nano-TiO2 has superior ability to enhance the resulting properties of SBR nanocomposites in comparison with either untreated or TEAB-treated nano-TiO2. Graphical Abstract

A comparison between polyethylene glycol (PEG) and polypropylene glycol (PPG) treatment on the properties of nano-titanium dioxide (TiO2) based natural rubber (NR) nanocomposites

The purpose of the present article is to modify the surface of nano-titanium dioxide (TiO2) and to investigate the reinforcing effect of both unmodified and surface-modified nano-titanium dioxide (TiO2) on the mechanical properties and thermal stability of natural rubber (NR) nanocomposites. Surface of nano-TiO2 is modified by polyethylene glycol (PEG) and polypropylene glycol (PPG). The effective surface modification of nano-TiO2 is evaluated by Fourier transform infrared (FTIR) spectra and field emission scanning electron microscopy (FESEM). The result notifies that the final properties of NR nanocomposites are dramatically improved in the presence of surface-modified nano-TiO2 in comparison to unmodified nano-TiO2. The excellent reinforcing capability of surface-modified nano-TiO2 is due to its better hydrophobicity and uniform dispersion within the NR matrix, as confirmed from morphological analysis. Furthermore, due to its small size PEG is better surface modifier for nano-TiO2 than PPG.

Surface modification of sol–gel derived nano zinc oxide (ZnO) and the study of its effect on the properties of styrene–butadiene rubber (SBR) nanocomposites

Very recently, nano zinc oxide (ZnO) has been successfully introduced as a cure activator for the reduction of ZnO level in the rubber industry. The purpose of the present work is to examine the appropriateness of surface-modified nano ZnO in the vulcanization of styrene–butadiene rubber (SBR). In the experimental part, the surface of nano ZnO is modified by stearic acid and bis[3-(triethoxysilyl)propyl]tetrasulfide (Si-69). Si-69-treated nano ZnO causes considerable enhancement in many properties such as maximum rheometric torque, modulus, tensile strength, elongation at break, cross-linking degree of SBR nanocomposite in comparison to conventional ZnO and unmodified or stearic acid-treated nano ZnO. Thermogravimetric analysis (TGA) reveals that Si-69-treated nano ZnO imposes better thermal stability than untreated or stearic acid-treated nano ZnO in the SBR vulcanizates. Morphological study indicates uniform dispersion of Si-69-treated nano ZnO within the SBR matrix and this fact accounts for better mechanical and thermal properties of SBR nanocomposite in the presence of Si-69-modified nano ZnO. This study concludes that Si-69-modified nano ZnO can be effectively applied as cure activator in place of nano ZnO to reduce the ZnO level in SBR compounds. This will lead to both economic advantages and environmental safety in the rubber industry.

Silica-coated nano calcium carbonate reinforced polychloroprene rubber nanocomposites: influence of silica coating on cure, mechanical and thermal properties

The main objective of the present work is to compare the influence of silica-coated nano calcium carbonate (SNCC) with uncoated nano calcium carbonate (NCC) as filler on the property enhancement of polychloroprene rubber (CR) composites. The CR nanocomposites containing SNCC exhibit superior curing, mechanical and thermal properties in comparison to NCC-filled CR nanocomposites. The fantastic enrichment in the resulting properties of CR nanocomposites containing SNCC is mainly due to better rubber–filler interaction resulting from the reasonably excellent dispersion of SNCC within the CR matrix. The more uniform distribution of SNCC in comparison to NCC within the rubber matrix is also confirmed from morphological analysis. Thus, in this article, we report SNCC as a new type of efficient filler to reinforce the ultimate properties of CR nanocomposites for the first time.

Development of a suitable nanostructured cure activator system for polychloroprene rubber nanocomposites with enhanced curing, mechanical and thermal properties

Nanostructured zinc oxide (ZnO) and magnesium oxide (MgO) are synthesized by sol–gel method and characterized by X-ray diffraction and field-emission scanning electron microscopy. The curing characteristics, mechanical, thermal and aging resistance properties of polychloroprene rubber (CR) composites in presence of both nanostructured and conventional cure activators in different combinations are determined. The CR composite containing 2 phr (parts per hundred parts of rubber) nano-ZnO along with 2 phr nano-MgO shows an excellent improvement in the curing characteristics as well as in the values of modulus and tensile strength in comparison to CR composite containing conventional cure activator system, i.e., 5 phr conventional ZnO along with 4 phr conventional MgO. Morphological analysis confirms the uniform distribution of nanosized cure activators within the CR matrix in comparison to conventional cure activators. Thermogravimetric analysis reveals that rapid degradation region for CR composite starts at higher temperature in presence of nanostructured cure activator system in comparison to conventional cure activator system. This study reveals that only 2 phr nano-ZnO in combination with 2 phr nano-MgO can successfully replace conventional cure activator system containing 5 phr conventional ZnO along with 4 phr conventional MgO with the enhancement of cure, mechanical and thermal properties of CR composites.