Synthesis of styrene‐g‐polyisoprene nanoparticles by emulsion polymerization and its effect on properties of polyisoprene composites

Abstract

The graft copolymerization of styrene onto nanosized polyisoprene (PIP) was carried out by using cumene hydroperoxide and tetraethylene pentamine as redox initiators. The high conversion and high degree of grafting could be achieved when a small particle was used as the core polymer. The grafting efficiency and monomer conversion increased with increasing reaction temperature and monomer concentration. Transmission electron microscopy indicated that the small PIP nanoparticles were completely coated with polystyrene (PS) by grafting resulting in a core shell morphology of nanosized graft PIP. Nanosized PIP and nanosized PS‐g‐PIP could be used as compatibilizers for vulcanized rubber latex. The addition of nanosized PIP and PS‐g‐PIP strongly influenced the mechanical properties of the natural rubber (NR)‐based compound. Incorporation of nanosized PIP and PS‐g‐PIP resulted in an improvement of the resistance of the compounds to heat aging. Copyright © 2011 John Wiley & Sons, Ltd.

Synthesis of polybutadiene-silica nanoparticles via differential microemulsion polymerization and their hydrogenated nanoparticles by diimide reduction

“…At a high monomer to water ratio (above 0.2), the monomer conversion and grafting efficiency decreased dramatically. This implied that at higher monomer to water ratio, polymerization of BD is more pronounced than graft polymerization onto SiO 2 since the grafting has a lower active surface area at the reaction site [24]. Moreover, most of the further added monomer molecules could diffuse into the existing polymer particles, which were larger than the newly nucleated particles, and monomer diffusion into the polymer particles required more time resulting in a decrease in monomer conversion [25].…”

Effect of structural factors on the physicochemical properties of functionalized polyanilines

“…An increase in the initiator decomposition rate results in a higher nucleation rate. [142][143][144] The use of ultrasonic or microwave radiation in the oxidative polymerization of aniline and its derivatives is an important way for achieving a nanoscale supramolecular structure in PANI and its derivatives. By changing the irradiation power and the reaction temperature, it is possible to control the size of the resulting particles, which is very important for the practical use of materials.…”

Effect of Impact Modifiers on Strength and Fracture Toughness of CFRPs

“…Specifically, in the tensile and flexural tests, 8 layers of G0926 fabric are used, in the fracture toughness and shear tests of UDC415 12 layers and finally in the impact test UDC415 10-layer fabric. In all The specimens for bend and tensile test have an average thickness of 3.05 mm, while the characteristics of the G0926 fabric used are nominal weight 375 g / m 2 and density 1.76 g / cm 3 . Thus, the fibre content of these composites is 55.89%.…”

“…For shear tests and fracture toughness, as mentioned above, a 12-layer UD fabric was used. The nominal weight of its surface is 415 g / m 2 , the specimens have an average thickness of 4.5 mm, while the density of the fabric is 1.82 g / cm 3 . Thus, the fibre content is 60.8%.…”

“…The introduction of the core-shell rubbers (CSR) in the fibre-matrix composite can absorb a larger quantity of energy and thus extend the life of the materials and their strength. The impact strength of the composites after the addition of CSR is improved through their ability to absorb the vibrations of the composites and terminate the propagation of cracks [3]. Despite the improved performance on fracture, this addition can negatively affect Young's modulus of the cured epoxy polymer, increase the viscosity of the resin or even decrease the glass transition temperature, resulting in harder processability and application of these composites.…”