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The vulcanization of natural rubber (NR)-blended acrylonitrile-butadiene-styrene (ABS) was carried out with a phenolic curing agent by a melt-mixing process. The NR compound was first prepared before blending with ABS. The effects of the phenolic curative contents (10, 15, and 20 phr) and blend proportions (NR/ABS ratio 5 50 : 50, 60 : 40, and 70 : 30) on the mechanical, dynamic, thermal, and morphological properties of the vulcanized NR/ABS blends were investigated. The tensile strength and hardness of the blends increased with increasing ABS content, whereas the elongation at break decreased. The strength property resulting from the thermoplastic component and the vulcanized NR was an essential component for improving the elasticity of the blends. These blends showed a greater elastic response than the neat ABS. The thermal stability of the blends increased with increasing ABS component. Scanning electron micrographs of the blends showed a two-phase morphology system. The vulcanized 60 : 40 NR/ABS blend with 15-phr phenolic resin showed a uniform styrene-co-acrylonitrile phase dispersed in the vulcanized NR phase; it provided better dispersion between the NR and ABS phases, and this resulted in superior elastic properties. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42520.

This article describes the effectiveness of online learning during the COVID-19 pandemic of the demonstration school. Teachers’ online instructional model, the availability of students’ online learning tools, as well as students’ and parents’ perspectives of, and satisfaction with, online learning was investigated. Participants were teachers (N = 70), students (N = 981), and parents (N = 981) from a demonstration school in Thailand during the second semester of 2021. The research design used a mixed method approach using survey questions administered to teachers, students, and parents. The findings revealed that most teachers preferred live-teaching (93.30%) through Microsoft Teams (96.70%) to facilitate online teaching and learning. Students had good online learning facilities, including learning tools and internet access. Only a small percentage of students (1.73%) did not have computer access for online learning. While online learning has proved to support the health of students during the pandemic, students and parents moderately agreed that there is no difference in effectiveness between traditional face-to-face learning and online learning (students = 41.87%, parents = 57.54%). They highly agreed that traditional face-to-face learning is still important for learning (students = 96.93%, parents = 90.40%). Students’ and parents’ preference of face-to face learning is attributed to the various challenges associated with online teaching and learning. Our research led to the development of an effective and suitable online learning management system for the COVID-19. Parents and students had high levels of satisfaction with online learning, demonstrating the effectiveness of this technique. These findings are valuable for educators, students and parents to adopt and promote online learning during the COVID-19 pandemic.

Dynamically vulcanized NR/ABS blends by phenolic curing were carried out using an internal mixer at 180 °C. The effect of NR/ABS ratio (i.e., 50/50, 60/40, 70/30) on mechanical, dynamical and morphological properties was investigated. It was found that the tensile strength and hardness increased with an increase in ABS loading whilst the elongation at break decreased, indicating that the strength and hardness attributed to thermoplastic component whereas the elasticity of the blends contributed to the vulcanized NR. The results showed that the 60/40 NR/ABS blend provided the well-balanced mechanical properties. The storage modulus of thermoplastic vulcanizates (TPVs) increased with increasing contents of rubber. This is due to that a higher content of vulcanized NR domain was dispersed in the ABS matrix. The results agreed well with the tan δ and complex viscosity of the TPV at various blend ratios. SEM micrographs of 60/40 NR/ABS blend showed that vulcanized rubber domains were dispersed in a continuous ABS phase and it contributed to greater interfacial adhesion between the two phases and thus provided superior properties.