The objective of this study was to improve the interfacial properties of bamboo fabric (BF)/epoxy (EP) composites and thus enhance their mechanical properties . BF was treated with 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidation system and N-hydroxyphthalimide (NHPI) oxidation system, respectively, to obtain BFO- T and BFO- N oxidation products with different surface morphologies . The effects of different oxidation treatments on the tensile strength ( σ c ) and elongation at break ( ε c ) of the composites were evaluated. Compared with the untreated BF/EP samples, BFO- T/EP showed a 56.9% increase in σ c with a non-significant change in the increase in ε c . BFO- N/EP showed a 30.1% increase in σ c , but the improvement of ε c reached 473.7%. The results of single-yarn pull-out tests and atomic force microscopy indicated that the proper size of grooves may be the key to improve the strength of the two-phase interface. The larger size of the grooves, the easier it is for the resin to infiltrate and fill the voids, thus forming occlusal structures that strengthen the interfacial bonding. Small-sized grooves, on the other hand, are not conducive to resin impregnation and therefore voids at the two-phase interface, thus hindering load transfer.
Bo Zhang,Songyue Liu,Lijie Yin,Ming Tian,Nanying Ning,Liqun Zhang,Wencai Wang
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 .
In this research, ultraviolet (UV) irradiation induced graft polymerization of glycidyl methacrylate (GMA) was performed to modify the surface properties of poly-p-phenyleneterephthamide (PPTA) fibers. The improvement of adhesion with a rubber matrix was achieved due to the introduction of epoxy groups. The successful grafting of GMA on the PPTA fiber surface was ascertained by characterization using X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and scanning electron microscopy (SEM). The tensile properties of PPTA fibers after each stage of surface modification were determined by tensile testing of single-filaments. A single-fiber pull-out test was applied to evaluate the adhesion of PPTA fibers with the rubber matrix. The pull-out force of grafted PPTA fibers exceeded that of the pristine fibers by 53.7%. Resorcinol–formaldehyde–latex (RFL) dipping was applied to further improve the adhesion properties. As a result, the fibers with GMA grafting followed by RFL dipping exhibited a 80.8% improvement compared with the pristine fibers and achieved much higher adhesion strength with rubber matrix, compared to the PPTA fibers modified with conventional industrial method of isocyanate (NCO) and RFL two bath dipping.
危险品化学品经营许可证（带存储）