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In this study, the surface of ultra-high-molecular-weight-polyethylene (UHMWPE) fibers was modified by ozone pretreatment, followed by ultraviolet (UV) grafting, to enhance the interfacial properties of UHMWPE fibers/rubber composites. The fibers were first pretreated by ozone to introduce oxygen-functional groups. The graft polymerization of glycidyl methacrylate (GMA) onto the ozone-treated fibers was implemented by UV irradiation. The effects of time and GMA concentration on the grafting efficiency were investigated. The modified fibers were characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS). The XPS and FTIR results revealed that GMA was successfully grafted onto the fibers with epoxy groups. SEM images confirmed that a continuous layer of poly-(GMA) (PGMA) was grafted onto the fibers. The interfacial adhesion force of UHMWPE fibers with rubber matrix was characterized by H pullout testing, which showed that the maximum force the fibers/rubber composites increased by 79% over that of the untreated fibers. [ABSTRACT FROM PUBLISHER]

New natural rubber (NR)/nitrile butadiene rubber (NBR)/hindered phenol (AO-80) composites with high-damping properties were prepared in this study. The morphological, structural, and mechanical properties were characterized by atomic force microscopy (AFM), polarized Fourier transform infrared spectrometer (FTIR), dynamic mechanical thermal analyzer (DMTA), and a tensile tester. Each composite consisted of two phases: the NR phase and the NBR/AO-80 phase. There was partial compatibility between the NR phase and the NBR/AO-80 phase, and the NR/NBR/AO-80 (50/50/20) composite exhibited a co-continuous morphology. Strain-induced crystallization occurred in the NR phase at strains higher than 200%, and strain-induced orientation appeared in the NBR/AO-80 phase with the increase of strain from 100% to 500%. The composites had a special stress–strain behavior and mechanical properties because of the simultaneous strain-induced orientation and strain-induced crystallization. In the working temperature range of a seismic isolation bearing, the composites (especially the NR/NBR/AO-80 (50/50/20) composite) presented a high loss factor, high area of loss peak (TA), and high hysteresis energy. Therefore, the NR/NBR/AO-80 rubber composites are expected to have important application as a high-performance damping material for rubber bearing. [ABSTRACT FROM AUTHOR]

ABSTRACT Bio-based elastomers used in industry have attracted much attention. We prepared bio-based engineering polyester elastomer (BEE) nanocomposites by mixing bio-based engineering polyester elastomers with carbon (CB). The CB/BEE nanocomposites were exposed to an artificial weathering environment for different time periods. Both its aging behavior changes and aging mechanism were investigated in this article. The tensile strength retention rates were each above 90% after aging at 100°C and 125°C for 72 h. CB/BEE nanocomposites exhibited good anti-aging properties. Furthermore, the chemical changes were detected by Fourier transform infrared spectroscopy and differential scanning calorimetry. The crosslink density changes during aging of BEE were determined as well. A plausible aging mechanism of BEE was proposed. It can be concluded that the thermal oxidation process gives priority to further crosslinking in the initial period of aging. As the aging time increases, chain scission becomes the dominant element in the subsequent thermal oxidation process. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40862. [ABSTRACT FROM AUTHOR]

• Water plays a different role in coal spontaneous combustion before and after the critical temperature. • CO and C 2 H 4 can be selected as the index gases. • The gas production during coal oxidation is related to the relative content of functional groups. To explore the influence of long-term water immersion on the spontaneous combustion characteristics of coal, temperature-programmed test system and In-situ Fourier transform infrared spectroscopy (In-situ FTIR) were used. Differences in gas production of soaked coal and raw coal showed that the process of long-term water immersion played a different role before and after critical temperature. In the stage of surface oxidation, moisture could inhibit the spontaneous combustion of coal, when the critical temperature point was exceeded, it played a promoting role instead. As an explanation in support of the above arguments, the relative contents of active functional groups in raw and soaked coal were compared, which indicated that the process of water immersion could affect relative contents of hydroxyl, aromatic hydrocarbon, aliphatic hydrocarbon and oxygen-containing functional groups, giving rise to an acceleration in the reaction process of coal oxygen and exhibiting higher tendencies toward spontaneous combustion. A practical consequence of this finding is the soaking mechanism should not be neglected in any precautionary or preventive measures to avoid potential spontaneous combustion in overlying goaf of shallowly buried and close distance coal seams. [ABSTRACT FROM AUTHOR]

Due to the chemical inertness of the polyester (PET) fiber surface, it often needs to be immersed in a traditional resorcinol-formaldehyde-latex (RFL) dipping solution before it can be used in rubber composite. However, the RFL dipping system contains toxic components, resorcinol and formaldehyde, and is gradually banned. In this article, a novel resorcinol-formaldehyde-free environmentally friendly adhesion promoter for dipping treatment of PET fiber was synthesized. Specifically, water soluble ethylene glycol diglycidyl ether (EGDE) and diethylenetriamine (DETA) were introduced into the new dipping solution to replace the toxic ingredients of resorcinol and formaldehyde in RFL dipping system. We use polyester fabrics to study the effects of reaction conditions, chemical structures and interfacial adhesion mechanism on the treatment results to achieve the level of conventional RFL treatment. The surface chemical compositions of modified PET fabrics were characterized by attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that the fabric surface was successfully coated with the dipping layer. In addition, interfacial adhesive properties between modified PET fabrics and rubber were studied. The results showed that the peel adhesive strength between the modified PET fabric and the rubber was 17 N/mm, which was comparable to the RFL dipping system. • A novel resorcinol-formaldehyde-free environmentally friendly adhesion for dipping treatment of fibers was synthesized. • Interfacial adhesive properties between modified polyester (PET) fabrics and rubber matrix were studied. • The peel adhesive strength between the modified PET fabric and the rubber matrix was 17 N/mm. [ABSTRACT FROM AUTHOR]

Considering the rapidity and lesser sample amount required, the Fourier Transform Infrared Spectra (FTIR) was often used to quantitatively determine the rubber content of Russian dandelion, guayule, etc. This is because their chemical structure are cis -1,4-polyisoprene (CPI) which has a unique and isolate skeleton stretching vibration peak at 835 cm −1 band, and is convenient for determining the rubber content. However, this method is not suitable for Eucommia Ulmoides (EU) gum which will crystallize easily at room temperature due to the regular chemical structure of trans -1,4-polyisoprene (TPI), that will restrict the skeleton stretching vibration of TPI greatly. As a result, its FTIR spectrum only shows a very small peak at 845 cm −1 band hiding among a number of crystalline peaks around nearby, thus it cannot be used to determine the rubber content of Eucommia ulmoides oliv ( E. ulmoids ) directly. Actually, these crystalline peaks could be eliminated easily by elevating the temperature over 60 °C, and a unique and isolate skeleton stretching vibration characteristic band at 845 cm −1 was left alone in the TPI's FTIR spectrum which can be used expediently to determine the content of EU gum. At the present paper, the Variable Temperature Fourier Transform Infrared Spectroscopy (VTFTIR) was used to determine the rubber content of E. ulmoides . The results indicate that the rubber content of E. ulmoides samples (1–40, 5–35, 22–11) provided by Northwest Agriculture and Forestry University (NAFU) are 4.66%, 4.04%, 4.32% respectively, and the errors of average value were less than 5% compared with Soxhlet Extraction. [ABSTRACT FROM AUTHOR]

The reaction mechanism and the interfacial modulus gradient of the interfacial transition layer between the environmentally friendly dipping system (PAL) and the rubber have not been fully studied. In order to better understand the chemical structures and nano-mechanical properties of the interface between the dip layer and the rubber, we used advanced atomic force microscope (AFM) and nanoscale Fourier transform infrared spectroscopy (nano-FTIR) to perform detailed analysis in this article. The characterization of interfacial nano-mechanical properties and chemical structures is very significant for the illustration of interfacial adhesion mechanism. AFM can effectively characterize the detailed interfacial modulus gradient and the thickness of interface, while nano-FTIR can comprehensively measure the interfacial chemical structures and the distribution of chemical bonds. The results suggest that the thickness of the interface between the PAL dip layer and the rubber matrix is 175 nm, and the crosslinking density of the interfacial layer is high, which explains that the failure location of fiber/rubber composites after pull-out tests occurs on the side of the rubber matrix. Similarly, the microstructure of resorcinol-formaldehyde-latex (RFL) system was also characterized, and the preparation of RFL usually requires carcinogenic and toxic substances such as formaldehyde and resorcinol. [Display omitted] • The reaction mechanism and interfacial modulus gradient of the PAL and the rubber have been fully studied. • Nano-FTIR can measure the interfacial chemical structures and the distribution of chemical bonds. • The thickness of the interfacial transition layer between the PAL and the rubber is about 175 nm. [ABSTRACT FROM AUTHOR]