Styrene butyl acrylate (SBA) copolymer latex nanoparticles which contain vinyltrimethoxysilane as binding agent were prepared using microemulsion polymerization and were used for coating sisal fiber. The structure of SBA and coated sisal fiber (CF) was confirmed by Fourier transform infrared spectroscopy. The effect of the surface coating of sisal fiber (SF) on the SF/natural rubber (NR) composite properties was systematically evaluated through curing characteristics, morphological properties, mechanical properties, water absorption resistance, biodegradability and dynamic mechanical analysis. As indicated from the morphological study, the coating of SF with SBA enhanced the interfacial adhesion between SF and the NR matrix. In addition, the tensile strength was improved by 26.9% and 43% after the addition of 5 and 10 phr (parts per hundred rubber), respectively, of CF to NR. The coating process improved the water resistance of SF/NR composite significantly especially at high SF loading level, where the composite that contained 30 phr CF absorbed 6.7% water compared to 13.2% for the composite containing uncoated sisal fiber (UF). Dynamic mechanical analysis confirmed that the coating process improved the interfacial adhesion between the SF and NR matrix as indicated from the higher values of storage modulus and lower values of maximum loss factor (tan δmax) recorded for composites containing CF compared to those containing UF. © 2021 Society of Industrial Chemistry.

No abstract

N ANOSTRUCTURED materials are an important subject in different applications. Zinc oxide (ZnO) nanoparticles have much attention because of their unique properties. The objective of this work is to synthesise zinc oxide nanoparticles by simplest chemical method (direct aqueous precipitation). Also, the effect of zinc oxide addition to polyurethane foam (PUF) on the mechanical and sound properties has been evaluated. Different concentrations of ZnO (0.25, 0.5, 1, 2 and 3 wt.%) were used. ZnO nanoparticles were characterized by some techniques such as X-Ray diffraction, Energy dispersive X-ray spectrometry and Transmission electron microscopy analysis. Scanning electron microscope was used to describe the dispersion state of the nanoparticles in the polyurethane foam. Density of PUF increased while the particle size decreased. Finally, it was confirmed that the mechanical and acoustic properties of polyurethane nanocomposites were improved and depend on the amount of nanozinc oxide.

A sponge rubber nanocomposite based on styrene–butadiene rubber (SBR)/nanoclay (montmorillonite, MMT) or nano-calcium carbonate (CaCO3) fillers with various foaming agent contents was produced by a simple technique, roll milling. The nanoparticles were examined by different techniques, such as X-ray fluorescence (XRF), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and Fourier-transform infrared (FT–IR). The sponge rubber nanocomposites were characterized by scanning electron microscopy (SEM) image analysis before and after exposures to radiation doses, as well as by the XRD patterns for the unirradiated samples. The different properties of the obtained nanocomposites, including their foaming degree, tensile strength, elongation at break, and thermal conductivity, were also investigated. The foam composites containing nano-CaCO3 possessed the best cell and crosslinking densities and mechanical properties among the other composites, while its foaming degree was the lowest. The results indicated that the thermal conductivity was reduced by increasing the foaming agent concentration. However, it increased as the radiation dose increased, and the optimum radiation dose was obtained at 75 kGy. The foam containing MMT exhibited an intermediate behavior while high thermal conductivity was recorded for the foam containing the CaCO3 nanoparticles.

A new antioxidant was prepared by graft copolymerization of N (4‐phenylenediamine) maleimide (pPDAM) onto natural rubber (NR). Fourier transform infrared technique was used to confirm the grafting of (pPDAM) onto the NR backbone. The grafted copolymer (NR‐g‐pPDAM) was incorporated into the ethylene propylene diene monomer rubber (EPDM) rubber mix as an antioxidant. For comparison purposes, a widely used antioxidant N‐(1,3‐dimethylbutyl)‐N′‐phenyl‐p‐phenylenediamine (6PPD) was used in addition to a blank sample without antioxidant. The rheometric characteristics of EPDM vulcanizates were determined using an oscillating disc rheometer. Different mechanical properties of the EPDM vulcanizates were measured before and after exposure to thermal and ultraviolet/ozone (UV/O3) accelerated aging. The results revealed that the grafted antioxidant NR‐g‐pPDAM is more efficient, for EPDM rubber vulcanizates than the commercial antioxidant (6PPD). EPDM containing grafted (NR‐g‐pPDAM) antioxidant exhibited promising properties, such that it is expected to fulfill major requirements of industrial, automotive, and construction applications.