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For styrene-butadiene rubber (SBR) compounds filled with the same volume fraction of carbon black (CB), precipitated silica and carbon–silica dual phase filler (CSDPF), filler-rubber interactions were investigated thru bound rubber content (BRC) of the compounds and solid-state1H low-field nuclear magnetic resonance (NMR) spectroscopy. The results indicated that the BRC of the compound was highly related to the amount of surface area for interaction between filler and rubber, while the solid-state1H low-field NMR spectroscopy was an effective method to evaluate the intensity of filler-rubber interaction. The silica-filled compound showed the highest BRC, whereas the CB-filled compound had the strongest filler-rubber interfacial interaction, verified by NMR transverse relaxation. The strain sweep measurements of the compounds were conducted thru a rubber process analyzer; the results showed that the CSDPF-filled compound presented the lowest Payne effect, which is mainly related to the weakened filler network structure in polymer matrix. The temperature sweep measurement, tested by dynamic mechanical thermal analysis, indicated that the glass transition temperature did not change when SBR was filled with different fillers, whereas the storage modulus in rubbery state and the tanδ peak height were greatly affected by the filler network structure of composites. [ABSTRACT FROM AUTHOR]

Epoxidized natural rubber (ENR) was introduced into rectorite (REC)/carbon black/natural rubber (NR) nanocomposites by two ways: (1) the direct incorporation of ENR and (b) the incorporation of a spray-dried REC/ENR compound. Transmission electron microscopy and X-ray diffraction analysis showed that the REC layers presented a nanodispersion structure in the REC/ENR compound. The vulcanization characteristics indicated that ENR increased the crosslinking density of the composites. The stronger reaction between the REC layers and ENR was verified by Fourier transform infrared spectroscopy in the spray-dried REC/ENR compound blended with NR versus that in the REC/NR master batch blended with ENR. As a result, the physical properties, such as the mechanical properties, cutting and chipping resistance, and abrasion resistance, of the composites were greatly increased by the addition of the REC/ENR compound. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

Rectorite (REC) powders modified by butadiene-styrene-vinyl pyridine rubber (VPR) were prepared by spray drying, designated as REC-VPRs. X-ray diffraction (XRD), Scanning electron microscope (SEM), and transmission electron microscopy (TEM) analyses showed that in the REC-VPRs, VPR did not intercalate into the intergallery of layers. However, compared with REC, the layers of REC-VPRs had more wrinkles and piled loosely. To strengthen the interfacial interaction between VPR and REC, a REC-VPR was treated by volatilized hydrochloric acid, resulting in the formation of ion bonds between REC and VPR, according to Fourier transform infrared spectra measurements. XRD analyses revealed that the intercalated structure emerged in acid treated REC-VPR filled styrene-butadiene rubber (SBR). However, the better dispersion was observed for the SBR composite filled with REC-VPR without acid treatment, indicating that a proper interfacial interaction between REC and VPR is the key to improve the dispersion of REC layers in SBR. Acid treatment did not improve the tensile and tear strengths of the SBR composite filled with REC-VPR. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2012 [ABSTRACT FROM AUTHOR]

A novel, effective approach to improve the cutting and chipping resistance (CCR) of carbon black (CB)-filled styrene butadiene rubber (SBR) composite was reported in this study. CCR of SBR was dramatically improved more than 30% by addition of 4 phr nanodispersed clay (NC), while not decreasing the stress at 100% and the Shore A hardness of the composite. The curing characteristics, loss tangent (tan δ), and the strength of filler network of the composites were further measured by a Disk Oscillating Rheometer and a rubber processing analyzer, respectively. It was found that the addition of NC led to a slightly lower crosslink density, higher tan δ, and stronger filler network, which contributed to the higher CCR. Therefore, the novel layered NC is more efficient in improving CCR when compared with CB. The results are expected to promote the application of NC in rubber industry. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

The article presents information on a study which examined the influence of in situ modification of silica with bis-(3-triethoxysilyl)-propyl)-tetrasulfide (TESPT) on filler network in silica filled solution styrene-butadiene rubber (SBR) compound. A review of the related literature is given. It presents the reagents and methods used including rubber processing analyzer (RPA) to characterize the filler network. A detailed discussion of the research findings is presented.

Aim: To investigate the effects of transforming growth factor-beta1 (TGF-beta1) and signal protein Smad3 on rat myocardial hypertrophy., Methods: The total protein was analysed by flow cytometer assay to judge the hypertrophy of myocardial cell incubated with different level of TGF-beta1 in cultured myocardial cells of neonatal rats. The models of rat cardiac hypertrophy were produced with constriction of the abdominal aorta. At the different time after the operation, the rats were killed, and the left ventricular mass indexes (LVMl) were investigated. The mRNA expressions of TGF-beta1 and Smad3 of cultured cells and hypertrophic left ventricles were assessed by RT-PCR, the protein expressions of Smad3 were assessed by Western blot., Results: In cultured neonatal myocardial cells, different level TGF-beta1 could significantly increase the total protein, and TGF-beta1 (3 ng/ml) could increase the expression of mRNA and protein of Smad3 and continued for 8 h of cultured cardiomyocytes. The LVMI and the expression of TGF-beta1 mRNA and Smad3 mRNA/protein of hypertrophic left ventricle were increased at the 3rd day after the operation and continued for 4 weeks. The peak expression of them was in 2 weeks after operation., Conclusion: TGF-beta1 has the effects on rat myocardial hypertrophy, signal protein Smad3 is included in the pathologic progress of rat myocardial hypertrophy.