Thermal properties, i.e. melting point and decomposition temperature of polymers, azodicarbonamide (ADC), and other additives mixture, are the most important information to determine the appropriate foaming process parameters. ADC has been widely used as a blowing agent for foam fabrication. Here, ADC will decompose and release gas which will be trapped in the melting polymer to make a foamed product. Originally, ADC has a decomposition temperature at around 220°C. In this study, the effect of Zinc Oxide (ZnO) addition on the thermal properties of intermediate product and Polyethylene/Ethylene Vinyl Acetate (PE/EVA) foam with ADC as the blowing agent was investigated. ZnO addition decreased the decomposition temperature of ADC. The thermal properties were characterized by Differential Scanning Calorimetry (DSC). The result showed that the decomposition temperature of ADC significantly decreased from the temperature of 220°C to 170°C with the increment of the ZnO.

Polymeric materials have been employed in a wide range of applications in both dry and wet environments. When these materials suffer damage, it becomes crucial to initiate repairs in order to mitigate further losses. The use of self-healing materials emerges as a promising strategy not only to address this issue but also possess the advantage of prolonging the product’s lifespan. Nevertheless, the development of self-healing materials tailored for wet environments presents a set of obstacles and complexities. The review examines the current state of research in the field and highlights the challenges associated with developing self-healing materials that can effectively repair damage in such environments. We discuss the self-healing mechanisms and various polymers that are extensively employed in the advancement of self-healing materials. We study the progress made in the research and development of self-healing materials specifically designed for wet environments. Furthermore, it provides a summary of various applications of self-healing materials in wet environments.

MATEC Web of Conferences, open access proceedings in Materials science, Engineering and Chemistry

Epoxy resin, a thermosetting polymer, is widely used across industries for its exceptional mechanical strength, heat resistance, and chemical stability. However, traditional epoxy derived from petroleum is not recyclable or remoldable, which limits its sustainability. To address these limitations, researchers have developed recyclable and reprocessable epoxy materials. Vanillin, a naturally occurring compound, has emerged as a promising alternative. Vanillin reacts with amines to form imine bonds, which serve as the foundation for reprocessable epoxy resins. These resins can be produced using vanillin either as a monomer or as a hardener. This review highlights recent advancements in the application of vanillin for these purposes, emphasizing the role of Schiff base mechanisms. The discussion begins with an overview of dynamic covalent bonds, particularly Schiff bases, in reprocessable epoxy systems. It further explores how vanillin derivatives function as monomers or hardeners in the development of epoxy vitrimer. Finally, the review addresses potential challenges and opportunities in utilizing vanillin for sustainable epoxy resin production. In the future, the research on vanillin-based epoxy vitrimer should focus on improving its stability and mechanical properties, optimizing its scalability, and assessing its environmental impact to advance sustainable materials and the circular economy.

Epoxy is a thermoset material with excellent mechanical performance, dimensional stability, as well as thermal and chemical stability. This performance is influenced by the cross-linked structure of epoxy. Usually, the cross-linker used for epoxy is amine and anhydride-based material. Other materials such as poly(carboxylic acid) can also be used as a cross-linker. In this study, the use of combinations of amine-based and poly(carboxylic acid) cross-linker is reported. A modified citric acid (CA) was synthesized in this study by reacting CA with ethylene glycol (EG) at various molar ratios. This modified CA was then mixed with the epoxy with multiple weight ratios. Thermal analyses such as differential scanning calorimeter (DSC) and thermogravimetry analysis (TGA) show that the curing and decomposition temperatures of epoxy are influenced by the type of cross-linker used. Curing temperature of epoxy with modified CA is 164.44°C while with amine based cross-linker is 57.43°C. The thermal stability of epoxy cross-linked with modified CA is higher compared to the one with amine-based cross-linker. Increasing the EG content in modified CA can decrease the decomposition temperature of the epoxy.

Process parameters are crucial to produce targeted qualities in polypropylene (PP)/clay nanocomposites, due to their roles on the generation of shear and diffusion. Thus, this research aims to observe their effects on structures and properties of PP/clay nanocomposites. Samples were produced by mixing PP, PP grafting maleic anhydride (PP-g-MA), and Cloisite 20A at fixed compositions, 88/9/3 wt%, respectively, in an internal mixer with variations on temperatures (210, 220, 230 °C) and speeds (60, 80, 100 rpm). Effect of mixing parameters on nanocomposite structures and properties were investigated from XRD, SEM and flexural properties. The results showed that all samples had intercalated as well as agglomerated structures. Further analysis on XRD and SEM showed that samples produced at high conditions (230 °C or 100 rpm) had similar structures. In contrast, low setting sample (210 °C and 60 rpm), despite its similarity on dispersion level, had longer agglomerates than that of mixed at high settings. Correlated both increase of d-spacing and agglomerates length to flexural properties suggested that modulus was more influenced by dispersion level, while strength was affected by agglomerates. However, it was worth to note that improvement on d-spacing, with availability of long agglomerates might not guarantee modulus and strength improvement due to low interfacial bonding.