Effect of methacrylic acid on the mechanical properties of peroxide-cured SBR vulcanizates filled with Al(OH)(3)

Methacrylic acid (MAA) was used as an additive for the modification of pero xide-cured styrene-butadiene rubber (SBR) highly filled with Al(OH)(3) fill er. The experimental results show that the introduction of MAA can improve the mechanical properties of the SBR vulcanizates to a great extent and tha t the mechanical properties of the SBR vulcanizates depend greatly on the M AA and Al(OH)(3) contents. At the Al(OH)(3) content of 150 phr, the hardnes s, modulus, tensile strength and tear strength of the SBR vulcanizates incr ease with increase in the MAA content. When the MAA content is 40 phr, the tensile strength, elongation at break and tear strength of the SBR vulcaniz ates are 15.7 MPa, 212%, and 38.7 kN/m, respectively. The oxygen index of t he SBR vulcanizates depends on the Al(OH)(3) content and is less affected b y the MAA content. The SBR vulcanizates have good thermal aging-resistance. Scanning electron microscope (SEM) study reveals the changes in the fractu red surfaces of the Al(OH)(3) filled SBR vulcanizates after using MAA, whic h is related to the changes in the mechanical properties.