Rui Li

To address the issues of significant polarity mismatch and weak interfacial bonding between polar starch nanoparticles (SNPs) and nonpolar natural rubber latex (NRL), epoxidized natural rubber (ENR) was introduced as an interfacial modifier in this work, aiming to optimize the interfacial interactions and comprehensive properties of SNPs/NRL composites. Mechanistic analysis revealed that ENR exerted a unique “bridging” effect: the epoxy groups on its molecular chains formed hydrogen‐bonded physical interactions with the hydroxyl groups on the surface of SNPs, while the carbon–carbon double bonds participated in the co‐vulcanization reaction of the NRL matrix, thereby constructing a dense interfacial cross‐linking network. This dual effect effectively inhibited the agglomeration of SNPs and significantly reduced the interfacial defects within the composites. The experimental results demonstrated that the optimal modification effect was achieved at an ENR loading of 5 phr. Compared with the neat control sample without ENR addition, the tensile strength of the composite was increased by 40.56%, the wet abrasion loss was reduced by 61.58%, the cross‐linking density reached the peak value, and the microscopic morphology of the composite exhibited a high degree of uniformity and densification. This work provides a theoretical basis for the interfacial design of high‐performance NRL‐based composites.

Thermoplastic vulcanized rubber (TPV) result in intermaterial incompatibility due to the thermodynamic incompatibility of the components that make up their soft and hard segments, which results in significant low‐temperature brittleness and poor mechanical properties of the material. And the low‐temperature properties of thermoplastic elastomers, especially based on ethylene propylene monomer/polypropylene (EPDM/PP) thermoplastic elastomers, and the corresponding mechanism of action have not been elucidated. The balance between low temperature performance and mechanical properties is a real challenge for TPV. In this paper, polyisobutylene (PIB1300) was introduced into the interstices of the molecular chain as an adhesive plasticizer to enhance the interfacial adhesion between PP and EPDM. The torque change showed that the presence of PIB1300 increased the interfacial interaction between PP and EPDM. The contact angle test and the calculation of the compatibilizer's position of action further confirmed that PIB1300 could be used as an effective compatibilizer to improve the compatibility of the material. When the amount of PIB1300 was 3 phr, EPDM/PP with both mechanical properties and compatibility, low temperature resistance, low temperature elasticity, and low temperature brittleness was finally determined, and the tensile strength of the material was 12.34 MPa, which was by 109.86%.

Metal coordination bonds can be coordinated to specific functional groups in polymers. This special coordination can give the material excellent self‐healing and mechanical properties. Nitrile rubber (XNBR)/CuCl ₂ composites were prepared by solid‐state blending. By changing the coordination reaction temperature, different coordination bonds were formed between the nitrile rubber and copper ions. The starting temperature of the coordination reaction was determined to be 100°C by observing the changes in the coordination reaction curve. With the increase of temperature from 100°C to 190°C, the copper ions' oxidation state was raised to 3, while part of C ≡ N was transformed to C=N at high temperature. Quantitative analysis revealed that the linear coordination [Cu ²⁺ –N _L ] was predominantly triple‐coordinated, and the curved coordination [Cu ³⁺ –N _B ] was coordinated in the form of ionic clusters. In addition to this, the formation of linear coordination bonds was easier and more reversible based on the calculation of the apparent activation energy of the coordination reaction. Macroscopically, the mechanical properties and self‐repairing ability of XNBR/CuCl ₂ ‐10‐100°C were higher than those of XNBR/CuCl ₂ ‐10‐190°C. The design of cross‐linked XNBR with good mechanical properties and recycling performance was of great significance in protecting the environment and realizing sustainable development. Highlights: XNBR/CuCl ₂ ‐10‐100°C composites mainly form linear coordination [Cu ²⁺ –3N _L ]. XNBR/CuCl ₂ ‐10‐190°C composites form bending coordination [Cu ³⁺ –NB]. [Cu ³⁺ –N _B ] is stronger than [Cu ²⁺ –N _L ] but less reversible.