Tear energy dependence of NR crack tip morphology.

Based on the real-time crack tip morphology monitoring, the influence of silane coupling agent (SCA) on the crackgrowth behavior of silica-filled natural rubber (NR) was analyzed. By using SCA, silica particles can be well dispersed and a fillermatrix network can be formed, which leads to lower crack-growth rate. Results indicate that a dosage of 5 wt % (with respect to silica loading) is the optimal content. The real-time observation and scanning electron microscopy (SEM) analysis proved that thin ligaments and dimples with homogeneous distribution appear on the crack tip. These crack tip morphologies reflect the low crackgrowth rate.

Crack growth mechanism of styrene-butadiene rubber influenced by silica nanoparticles.

In the present work, functionalized liquid isoprene rubber (FLIR) was used to improve the filler dispersion and filler-rubber interaction in the silica filled natural rubber system. By the infrared spectra and scanning electron microscopy, it was proved that the FLIR was successfully grafted on the silica and the functionalized silica was dispersed in the NR matrix homogeneously. Based on the real-time crack tip morphology monitoring method, the influence of FLIR on the crack growth behavior of NR filled with silica was analyzed. By the adding of FLIR, the crack resistance of the natural rubber embedded with functionalized silica is remarkably increased. When the weight ratio of FLIR to silica is 3:10, the NR composite has the best crack resistance. V C 2015 Wiley Periodicals, Inc.J. Appl. Polym. Sci. 2016, 133, 42972.