Synthetic rubber Ethylene Propylene Diene Monomer (EPDM) is extensively utilised throughout multiple sectors, especially for applications including seals, gaskets, hoses, and O-rings that directly interact with liquids. One of the challenges in using EPDM is improving its impermeability-related properties, which can be achieved by reducing the free volume within the material. This can be done by increasing the cross-link density, which is influenced by several factors, including the use of accelerators. This study aims to evaluate the effect of varying accelerator concentrations on the cross-link density of EPDM. Accelerators were added in different amounts: 0.6 phr (per hundred rubber), 1.2 phr, 1.8 phr, and 2.4 phr. The variations were analysed through rheology tests, tensile tests, cross-link density tests, and swelling tests. The findings indicate that the incorporation of accelerators markedly influenced the rheological properties of EPDM, with increased accelerator levels necessitating greater torque during processing. Tensile, cross-link density, and swelling tests indicated that the optimal accelerator concentration for achieving the best cross-link density and performance was 1.8 phr. Further increases in accelerator concentration did not necessarily lead to higher cross-link density, indicating that a higher accelerator concentration does not always guarantee better cross-linking results.
Natural rubber (NR)/acrylonitrile-butadiene rubber (NBR) blends suffer from poor interfacial compatibility, which limits their performance. In this study, epoxidised natural rubber (ENR) was used as a compatibiliser, whereas halloysite nanotubes (HNTs) and APTES-functionalised HNTs (AHNTs) (0–10 phr) were incorporated to enhance reinforcement. Surface functionalisation improved filler dispersion and interfacial adhesion through chemical interactions. At the optimum loading (6 phr), tensile strength increased by 129
With particular attention to awareness, perception, and adoption of recommended cultivation and processing practices, this study examined the spatial dynamics of technology adoption among the smallholder rubber farmers in Sri Lanka. The research analysed how neighbourhood effects influence different stages of the adoption process and the implications for policy using Moran’s I statistics, spatial econometric models, and spatial mapping. Significant positive spatial autocorrelation was found in both awareness and perception, demonstrating that knowledge and attitudes diffuse effectively through farmer networks and local interactions. By contrast, while adoption also exhibited statistically significant positive spatial autocorrelation, its degree of spatial clustering was markedly weaker than that of awareness and perception. Once individual-level covariates were controlled for in the spatial autoregressive model, the spatial dependence in adoption became statistically insignificant, suggesting that behavioural change is driven primarily by individual-level conditions rather than spatial contagion. However, farmers’ awareness and perceptions are strongly associated with adoption, indicating that while spatial proximity facilitates the spread of information and attitudes, the adoption decision is shaped by individual resources and farm-level conditions. The findings highlight a diffusion hierarchy; in particular, awareness and perception function as spatially driven precursors to adoption. Spatial spillovers could be leveraged by encouraging farmer-to-farmer learning, demonstration plots, and farmer organisations to fast-track the diffusion of knowledge and attitudes. Simultaneously, targeted measures should be employed to overcome constraints that hinder adoption, such as limited credit access, input support, and assistance with labour-intensive practices.
This study explores the effect of using citric acid (CA) as a sustainable, non-toxic alternative green co-crosslinker in the preparation of pre-vulcanised ENR/CA/S blend films. The work also focuses on achieving complete pre-vulcanisation within 24 h by optimising both compounding time and maturation time. Results show that increasing the compounding time to 4 h reduces the toluene swell index (TSI) to 1.70. The incorporation of 5–10 phr of CA, in combination with sulphur, contributes to improved crosslinking characteristics, as reflected by a reduced TSI value and enhanced mechanical properties. However, pH remains the primary factor governing crosslink density, while CA plays a secondary role by promoting additional interactions within the network. The pH of the ENR/CA/S latex decreases as CA content increases. A low pH at high CA content significantly reduces both mechanical strength and thermal stability of ENR/15CA/S. The pre-vulcanised ENR/5CA/0.9S exhibits the optimal performance, with a tensile strength of 4.18 MPa and a glass transition temperature (Tg) of –21.77 °C. This work highlights the potential of CA as a vulcanising supportive crosslinker in a sulphur-based vulcanisation system for latex applications, which opens new possibilities for developing diverse latex-dipped products.
Mechanical, thermal, tribological, flammability, and water absorption behaviours of vinyl ester composites under varied service temperature circumstances are examined in this work in relation to the influence of Citrus maxima peel-derived biochar and asparagus bean stem fibre treated with KOH–silane. To improve interfacial compatibility, the biochar was modified using a combination of alkali and silane treatment after being created by controlled pyrolysis. Using 50 °C and 70 °C as service temperatures, composites were made with biochar loadings ranging from 1 to 5 vol
