Publications

Poly(vinyl chloride)(PVC)/halloysite nanotubes (HNTs) nanocomposites were prepared by melt blending. The effects of HNT content on the mechanical properties, morphology, and rheological properties of the nanocomposites were investigated. The results showed that HNTs were effective in toughening and reinforcing PVC nanocomposites. The notched impact, tensile and flexural strength, and flexural modulus of the nanocomposites were remarkably increased compared with those for the pure PVC. Scanning electron microscopy (SEM) results illustrated the ductile behavior of the nanocomposites, with a possible cavitation mechanism. Transmission electron microscopy (TEM) results showed that HNTs were uniformly dispersed in the PVC matrix. Interfacial interaction of hydrogen bonding between the HNTs and PVC matrix was substantiated. The plasticization times of PVC/HNTs nanocomposites were found to be shorter and the equilibrium torque was higher than that for the pure PVC.

Silica-filled rubber composite is the main component of the "green tire" featured with a high fuel economy. Nowadays, incorporating sulfur-containing silane coupling agents (SSCAs) to improve the compatibility between silica and rubber is essential to optimizing the comprehensive properties of the resultant composites. However, SSCA synthesis requires multistep procedures and organic solvents and many intractable issues, such as low modification efficiency and volatile organic compound (VOC) emissions, cannot be resolved with regard to the use of SSCAs. Herein, we presented the facile synthesis of an epoxy-engineered polysulfide (SPVE) via inverse vulcanization of styrene, 1,2-epoxy-4-vinylcyclohexane, and sulfur and utilized it as a new-brand modifier for silica-filled rubber composite. The coupling mechanism of SPVE is revealed. Specifically, the polysulfides of SPVE can graft onto rubber chains; meanwhile, the epoxy groups of SPVE readily react with silanol groups on the silica surface, creating molecular linkages between rubber and silica. Consequently, incorporating SPVE remarkably improves silica dispersion and enhances the interfacial adhesion of the composites, thereby leading to superior mechanical properties and significantly decreased hysteresis loss. Compared with the commonly used SSCA, bis[3-(triethoxysilyl)propyl] tetrasulfide, SPVE exhibits a higher coupling efficiency without VOC emissions, providing an environmentally friendly solution for the manufacture of energy-saving tires.

Creating segregated structure within composites can significantly improve electrical conductivity but usually compromises mechanical properties. In this contribution, we introduced a straightforward and universal method to fabricate segregated rubber composites with a rare integration of high electrical conductivity and mechanical robustness by utilizing an inverse vulcanized copolymer (SP) as an adhesive to bind the segregated domains. Specifically, sulfur-crosslinked butadiene styrene rubber (SBR) granules were mixed with SP and carbon nanotubes (CNTs), followed by compression molding. CNTs embedded within SP are strategically dispersed along the boundaries of SBR granules, and the reaction of SP with SBR granules creates covalent bonding among the segregated domains and increases their crosslinking density. The segregated skeleton constituted by highly interconnected CNTs is robust, which imparts the composites with high electrical conductivity that is stable upon deformations and is able to heal after damage. In addition, the rigid segregated skeleton preferentially ruptures to dissipate enormous energy, and the cohesive interphase facilitates chain finite extensibility in the highly crosslinked segregated domains, resulting in remarkable enhancements on the tensile strength and modulus of the composites. The universality of this strategy is further demonstrated by using ground waste tyre rubber as matrix and boron nitride sheets as filler.

Constructing three-dimensional segregated graphene (3DG) network in polymer matrix is very effective in fabricating highly conductive polymer composites. However, it remains challenging to control the distribution of graphene with a concise and efficient method though the past efforts have been made. In this contribution, we propose a novel hydrothermal self-assembled strategy in combination of the post-impregnation process to prepare highly conductive polymer/graphene composites. Specifically, styrene-butadiene rubber/graphene nanocomposites with a three-dimensional graphene network (3DG-SBR) were prepared by employing the hydrothermal self-assembling, followed by impregnating by silver nitrate. The resultant graphene/styrene-butadiene rubber/silver particle (3DG-SBR-Ag) nanocomposite with 1.66 vol% of graphene exhibits the conductivity of 512 S m−1, which is competitive to those prepared by template-guided assembly strategy. Impressively, the polymer composite possesses mechanical robustness due to the strong interfacial reaction between graphene and polymer matrix. This synthetic approach for graphene-based nanocomposites is generic, scalable, flexibility in complex geometry and cost-effective. The as-prepared products could potentially be applied as competitive candidates for practical application in electromagnetic wave absorption and electromagnetic interference shielding.

The reinforcement effects of halloysite nanotubes on styrene-butadiene rubber and the modification effect of epoxidized natural rubber on styrene-butadiene rubber/halloysite nanotubes composites were studied. The structure, morphology and properties of styrene-butadiene rubber/halloysite nanotubes composites before and after the incorporation of epoxidized natural rubber were investigated. The results indicated that epoxidized natural rubber can promote the dispersion and orientation of halloysite nanotubes in styrene-butadiene rubber matrix at nanoscale and strengthen interfacial combination between halloysite nanotubes and styrene-butadiene rubber by the formation of covalent bonds and hydrogen bonds between epoxidized natural rubber and halloysite nanotubes. Consequently epoxidized natural rubber can improve the mechanical properties of the vulcanizates of styrene-butadiene rubber/halloysite nanotubes composites. Besides epoxidized natural rubber can decrease the rolling resistance of the vulcanizates and increase the wet grip property of the vulcanizates.

Individually dispersed graphene colloid is prepared using common and industrially available fluorescent whitening agents (FWAs) as stabilizers. Characterizations by UV-vis, fluorescence and Raman spectra demonstrate that FWAs are successfully anchored onto graphene sheets by π–π interaction. The results from AFM indicate the individual dispersion of graphene sheets in water. FWAs are demonstrated as highly efficient in suspending graphene with high concentration(6.2 mg ml−1). Subsequently, the obtained graphene sheet is incorporated into a chitosan (CS) matrix by solution casting to fabricate CS/graphene composites. Morphological observations substantiate the homogeneous dispersion of graphene in the CS matrix and the strong interfacial adhesion between them. The significant improvements in tensile strength and toughness of the composite films are concurrently observed.

High gas barrier rubber composites are crucial for the applications requiring the combination of high resilience and gas impermeability. Layered fillers are commonly used to enhance the gas barrier performance by reducing free volume and creating tortuous gas diffusion paths. However, it remains challenging to strengthen interfacial interactions and manipulate filler distribution, which significantly affect free volume and gas diffusion paths. Herein, we present a facile strategy to build a segregated structure in modified rubber composites with dynamic interfacial cross-linking toward mechanically robust, high gas barrier elastomer composites. Concretely, boehmite (BM) nanoplatelets modified with biobased phytic acid (PA) are utilized to cross-link epoxidized natural rubber (ENR), forming dynamic β-hydroxy phosphate ester cross-links for strong interfacial interaction. This system allows a segregated structure to be readily established by hot pressing the compounds containing ENR gum, PA-modified BM, precross-linked ENR granules and zinc acetate. The volume exclusion effect of ENR granules drives the selective dispersion of BM, generating a two-phase segregated structure with the bridged interfaces across phases formed via bond exchange of dynamic cross-links. This results in excellent gas barrier performance along with distinctly improved mechanical properties. Notably, the N2 permeability of the segregated composites is reduced by 90% to 4.23 × 10–19 m3·m/(m2·s·Pa) compared to neat ENR. Additionally, improved fire safety is achieved benefiting from the combined effects of PA, BM, and the segregated structure. This work offers a promising and scalable approach for fabricating high-performance elastomer composites that combine outstanding gas barrier properties, mechanical durability and flame retardance, making them suitable for a wide range of demanding applications.

Bacteria, viruses, and temperatures change can affect the preservation of food and medicines, so it is necessary to develop an intelligent textile for antibacterial and thermal regulation. In this paper, we used coaxial electrospinning technology to achieve antibacterial thermo-regulating intelligent textiles. The polyacrylonitrile (PAN)/curcumin is the sheath, and n-octadecane is the core. The composite fiber has excellent comprehensive properties. When the curcumin concentration is 10 wt%, the antibacterial effect is the best, and the bacteriostatic rate is 100%. When the core feed rate is 0.25 mL/h, the latent heat can reach 123.94 J/g. The multifunctional textiles have potential application value in the clothing fabrics, preservation and storage quality of functional foods, biomedical products, and other fields.

Transition bimetallic phosphides (TMPs) are a prospective catalytic material for HER. In this paper, inexpensive red phosphorus (P4) was doped into the homogeneous solution as a phosphorus source, and self-supported N-doped carbon nanofibers loaded with Ru-modified cobalt phosphide nanoparticles catalysts (Ru@Co2P/CNFs) were successfully prepared by electrostatic spinning technique combined with high temperature carbonization. The Ru@Co2P phosphide nanoparticles were uniformly dispersed on the surface of carbon fibers with three-dimensional network structure. Due to the synergistic effect between Ru and Co2P systems, the prepared Ru@Co2P/CNFs catalysts have excellent hydrogen evolution reaction activity and stability in alkaline solutions with N-doped conducting carbon matrix and large specific surface area active sites, only need an overpotential of only 48 mV at a current density of 10 mA cm-2, which is better than that of the noble metal Pt/C (52 mV). In addition, the Ru@Co2P nanoparticles were encapsulated by a carbon layer to prevent the catalyst from corrosion during long-term operation, and their HER performance did not change significantly after 40 h of operation, showing long-lasting stability. This research provide a new idea for exploring new self-supported network structured phosphide catalysts with low cost and high activity.

It is still a huge challenge to implement multiple energy dissipation mechanisms into polymers toward strong yet tough elastomers. Here, we describe a biomimetic design for diene-rubber by incorporating carbon nanodots (CDs) into a chemically cross-linked network. The high-functionality CDs serve as both physical and chemical cross-linkers, which give rise to a covalent network that interlinks multiple chains with nonuniform lengths, and interfacial hydrogen bonds. Upon stretching, the hydrogen bonds preferentially detach, leading to the orientation of short covalent bridging, which contributes the forward onset of strain-induced crystallization. The subsequent rupture of short covalent bridging, together with the successive detachment of hydrogen bonds result in further orientation of hidden length, which enhances the crystallinity. Consequently, the samples exhibit an integrated improvement of strength and toughness, and intact stretchability. We envisage that this strategy may provide a new avenue to implement biomimetic design for high-performance elastomers through multiple energy dissipation mechanisms.

A green approach is explored in crosslinking diene rubbers by using an inverse vulcanised co-polymer of sulfur and styrene.

Ordinary packaging film only has the functions of storing food and transporting food, while the external environment can affect the storage period of food. In this study, a common degradable material, polylactic acid (PLA), was chosen as the base material, and the material was endowed with antibacterial function by adding curcumin (Cur). Coaxial electrostatic spinning technology has a unique advantage in the preparation of core‐sheath structured fibers, and a PLA/Cur/n‐octadecane (OD) phase change thermoregulation fiber was prepared by selecting OD as the core material, which gives the fiber film thermoregulation function. The fiber structure, mechanical properties, and thermal properties were characterized. The antibacterial activity of the composite films against Escherichia coli and Staphylococcus aureus was investigated. The temperature regulation function of the composite film was evaluated, and the unique core‐sheath structure endowed the fiber film with a temperature regulation function. The storage of bananas was studied in which to explore the effect on food preservation. The composite films showed excellent bactericidal as well as antioxidant properties and successfully delayed the warming phenomenon.

Novel biobased isosorbide-containing copolyesters (PBISI copolyesters) with both biocompatibility and sustainability were synthesized by using commercially available biobased diols and diacids. Due to the presence of itaconate in copolyesters, it can be readily crosslinked by peroxide into a crystallizable network. The structure and thermal properties of PBISI copolyesters were determined by 1H NMR, FTIR, DSC, and WAXD. The chain composition, melting point and crystallinity of the PBISI copolyesters can be tuned continuously by changing the content of isosorbide. The crosslinked copolyester is demonstrated to be a promising shape memory polymer (SMP) with excellent shape memory properties including shape fixity and shape recovery rate close to 100%. The switching temperatures of PBISI-based SMPs can be tuned between 26 °C and 54 °C by altering the composition of PBISI copolyesters and curing extent. Cell adhesion and proliferation were adopted to evaluate the potential biocompatibility of PBISI-based SMPs, and the results indicated that all the PBISI-based SMPs were essentially noncytotoxic, making them suitable for fabricating biomedical devices.