Inspired by the micro structure of loofah sponge in nature, this article successfully employs a biomimetic approach to develop a novel series of natural Eucommia rubber foamed materials with excellent shape memory properties. This article explores the characteristic features of natural Eucommia ulmoides rubber foamed materials, including the foaming process, mechanical properties, shape memory performance, and adsorption properties. This paper introduces the innovative use of natural Eucommia ulmoides rubber’s shape memory properties to create a temperature-responsive foam adsorbent material. The foamed material’s unique ability to modify its pore structure through simple compression and heating processes offers tailored adsorption speed and capacity for varied practical applications. The adjustable adsorption properties of this foamed material present novel opportunities for its utilization in adsorption applications.

This paper extends previous studies by the authors that aimed to describe the effect of apparent cross-link density (CLD) of the rubber polymer networks on the fracture mechanism caused by cut and chip (CC) wear of natural rubber (NR), demonstrating the positive effect of conventional vulcanization (CV). This work is focused on the determination of the effect of CLD while keeping constant the accelerator-to-sulfur ratio A/S = 0.2, typical for CV systems. For this ratio, different sulfur quantities were chosen, and the concentration of the accelerator N-tert-butyl-benzothiazole sulphonamide (TBBS) was calculated to achieve CLDs in a range from 35 to 524 μmol・cm^–3. Standard analyses such as tensile tests, hardness, rebound resilience and DIN abrasion were performed. From these analyses, the optimum physical properties of the NR-based rubber were estimated to be in the CLD range of approximately 60 to 160 μmol・cm^–3. A CC wear analysis was performed with an Instrumented cut and chip analyzer (ICCA) and it was found that the highest CC wear resistance of the NR is in the CLD range of 35 to 100 μmol・cm^–3. Furthermore, the effect of straininduced crystallization (SIC) of NR on CC wear and its dependence on the CLD region was discussed. For the first time, we determine a CLD range for a CV system in which the material achieves both optimal mechanical properties and CC wear resistance.

The present study aimed to prepare prevulcanized latex from modified natural rubber (NR) latex, graft copolymers of natural rubber and poly(vinylbenzyl chloride), NR-g-PVBC. The prevulcanized latex was prepared by heating NR-g-PVBC latex in the presence of adipic acid dihydrazide (ADH). The study showed that the tensile strength of the NR-g-PVBC films with ADH was significantly higher than that without ADH. Interactions of NR-g-PVBC with ADH were further investigated using X-ray photoelectron spectroscopy (XPS). Higher storage modulus (E′) in the rubbery plateau region was also observed for the films with ADH than that without ADH. These results corroborated that the crosslinking reaction occurred in the film with the addition of ADH. It was found that the optimal prevulcanization time was 20 min at 55 °C. After that, the effect of storage on the tensile properties of the prevulcanized latex was studied. Atomic force microscopy (AFM) analysis was performed to follow changes in the surface morphology of films obtained from the prevulcanized latex. A zeta potential value of –37.83 was observed for the prevulcanized latex after being stored for 60 days. Therefore, the present study demonstrated that grafting poly(vinylbenzyl chloride) onto NR particles offered an opportunity to prepare a new type of prevulcanized latex. This new system was accelerator-free and zinc-free, considered more environment-friendly than a sulfur-prevulcanization system.

Epoxidized natural rubber (ENR) with varying levels of epoxide groups ranging from 10 to 50 mol% was prepared and dynamically phenolic vulcanized by blending it with poly(ether-block-amide) copolymer (PEBA). The results indicate that the thermoplastic vulcanizates (TPVs) of ENR/PEBA blends display a sea-island morphology and enhance a number of properties. Specifically, increasing the epoxide content and PEBA proportion enhances strength properties, including higher Young’s modulus (stiffness), toughness, tensile properties, and hardness, along with smaller vulcanized ENR domains dispersed in the PEBA matrix. Moreover, the decrease in tension set values indicates an improvement in the elastic properties. The attributed cause of this is the interaction between the polar groups present in the phenolic-cured ENR domains and the PEBA molecules. As a result, interfacial adhesion between the ENR domains and PEBA interfaces improved, contributing to the observed enhancements in the strength and elastic properties of the TPVs with smaller ENR domains. Furthermore, an increase in the epoxide content was found to be correlated with a decrease in tanδ and tension set, which further supported the observed improvements in strength and elasticity. Additionally, the ENR/PEBA blends showed a single glass transition temperature (T_g), while pure PEBA exhibited two T_gs. The presence of a single T_g in the ENR/PEBA blend is attributed to the overlapping of the T_g of the ENR and PEBA immiscible blend components.