Publications

Polydopamine (PDA) is a natural melanin derived from marine mussels that has good biocompatibility, biodegradability, and photothermal conversion ability. As a new coating material, it offers a novel way to modify the surface of various substances. The drug loading capacity and encapsulation efficiency of PDA are greatly improved via the use of mesoporous materials. The abundant pore canals on mesoporous polydopamine (MPDA) exhibit a uniquely large surface area, which provides a structural basis for drug delivery. In this review, we systematically summarized the characteristics and manufacturing process of MPDA, introduced its application in the diagnosis and treatment of cancer, and discussed the existing problems in its development and clinical application. This comprehensive review will facilitate further research on MPDA in the fields of medicine including cancer therapy, materials science, and biology.

Elastomers with unique high elasticity are recognized as strategic materials. The development of elastomers with the combination of high-performance and functionality is of great importance. In recent years, inspired by the structural characteristics of natural materials, the concept of sacrificial bonding has been successfully applied in the design of elastomeric materials, aiming at significantly improving mechanical and functional properties. In this short review, followed by brief description of the principle of sacrificial bonding, we summarize the main progress of the design of the elastomers with sacrificial bonds, and the main performance characteristics. The sacrificial units, including the covalent and non-covalent sacrificial bonds, may be engineered in rubber chains or the interfaces of rubber nanocomposites. In addition, the mechanisms of sacrificial bonding in conferring the functionalities have been described. Several important functionalities, including shape memory effects, damping and self-healing capability combined with robustness, are introduced. Based on the state of the art of the elastomers with sacrificial bonds, the prospective and challenges of are accordingly presented and discussed.

Two kinds of thiol ionic liquids (ILs), 1-methylimidazolium mercaptopropionate (MimMP) and bis (1-methylimidazolium) mercaptosuccinate (BMimMS), were investigated as novel interfacial modifiers for styrene butadiene rubber/halloysite nanotubes (SBR/HNTs) composites. According to model compounds, it was found that their affinities toward HNTs were originated from hydrogen bonding and that they could be grafted onto SBR chains via thiol-ene reactions. The ILs addition could promote vulcanization and effectively facilitate HNTs dispersion in rubber matrix. The interfacial interaction, quantitatively evaluated by a proposed equation based on rubber elasticity and reinforcement theory, was consistently increased. Mechanical properties of SBR/HNTs vulcanizates were largely improved and better than those of the 3-mercaptopropyl trimethoxysilane modified system. The BMimMS’s efficiency on modifying SBR/HNTs vulcanizates was higher than the other for its Gemini structure. Significantly mechanical improvements and lowered mechanical loss in the range of 50–80 °C were correlated to the improved HNTs dispersion and strengthened interfacial interactions.

No abstract is provided for this article.

It is a challenge to simultaneously achieve high stretchability, high modulus, and recoverability of polymers. Inspired by the multiphase structure of mussel byssus cuticles, we circumvent this dilemma by introducing a deformable microphase-separated granule with rich coordination into a ductile rubber network. The granule can serve as an additional cross-link to improve the modulus, while the sacrificial, reversible coordination can dissociate and reconstruct continuously during stretching to dissipate energy. The elastomer with such a bioinspired multiphase structure exhibits over a 10-fold increase in toughness compared to the original sample. We envision that this work offers a novel yet facile biomimetic route toward high-performance elastomers.

So far, most of the preparation methods for polymer/boron nitride nanosheets (BNNSs) composites are not suitable for mass production. Here, cost-effective and environmentally friendly water/ethanol were selected as the solvents to prepare BNNSs slurry on large scale by liquid exfoliation/solvent exchange. The slurry was then compounded with styrene-butadiene rubber (SBR) to form the rubber/BNNSs composites via conventional two-roll milling. The sulfide-containing silane was introduced to modify the interface between BNNSs and the rubber. The silane modified BNNSs (Si-BNNSs) has been characterized by FTIR, XPS and TGA. It is found that, with in situ modification of the silane, the rubber/BNNSs composites exhibited significantly improved thermal conductivity. With 10.5 vol% Si-BNNSs incorporated, the thermal conductivity of the composites is increased by 253%, comparing to the neat SBR. Meanwhile, the mechanical properties of the composites are simultaneously largely enhanced. The scalable yet environmentally-friendly slurry approach paves the way for industrial-scale utilization of BNNSs in thermally conductive polymer composites.

Biobased elastomers (bioelastomers) with high strength and good biocompatibility have emerged as promising biomaterials for soft tissue engineering. In the present work, we synthesized a series of biobased copolyesters, converting semicrystalline copolyesters into elastomers by introducing isosorbide, a bicyclic carbohydrate-based diol. The molecular weights, polymer structures and thermal transitions of the synthesized bioelastomers were characterized by GPC, NMR, FTIR, TGA, DSC and WAXD. The composition, melting point, and crystallinity of the bioelastomers could be tuned by changing the content of isosorbide. Furthermore, high strength composites could be prepared by compositing the synthesized bioelastomers with nanosilica. To substantiate the potential biocompatibility of the reinforced bioelastomers, the cell adhesion and proliferation were evaluated, and the results indicated that the reinforced bioelastomers were essentially noncytotoxic. The combination of sustainability, high strength and noncytotoxicity makes these bioelastomers potential candidates for high-strength biomedical materials.

The dispersion of filler and interfacial interaction are crucial in determining the properties of rubber composites. Aiming to improve the dispersion and filler–rubber interaction, we introduce rubber graft bearing oniums in a rubber/silica composite. To fulfill this goal, the graft, which is prepared via thio‐ene click reaction between 1‐methylimidazolium mercaptopropionate (MMP) and the pendent vinyl groups of a solution‐polymerized styrene‐butadiene rubber (SSBR), is introduced into the silica‐filled styrene‐butadiene rubber (SBR) composite. The dispersion of silica and interfacial interaction are improved via hydrogen bonding interaction. Moreover, the graft exhibits catalytic effect toward the silanization, which can improve interfacial interaction in the composites with bis [3‐(triethoxysilyl) propyl] tetrasulfide. With 2 phr of the graft, the tensile modulus (stress at 300% strain) is increased by 18% and the abrasion loss is decreased by 31%. This study opens a new attempt to improve the filler dispersion and filler–rubber interaction in the composites with onium‐bearing polymers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 48243.

Transition metal phosphides (TMPs) are a promising catalyst material for the hydrogen evolution reaction (HER). In this study, we introduced inexpensive red phosphorus (P4) into a homogeneous solution as a phosphorus source. Using the electrostatic spinning technique combined with high temperature carbonization, we successfully prepared self-supported carbon nanofibers doped with nitrogen (N) and loaded with ruthenium (Ru)-modified cobalt phosphide (Co2P) nanoparticles catalysts (Ru@Co2P/CNFs). The Ru@Co2P phosphide nanoparticles were evenly distributed on the surface of the carbon fibers, forming a three-dimensional network structure. The synergistic effect between the Ru and Co2P systems resulted in excellent catalytic activity and stability for the hydrogen evolution reaction in alkaline solutions. The N-doped conducting carbon matrix and large specific surface area of the active sites contributed to this enhanced performance. The Ru@Co2P/CNFs catalysts only required an overpotential of 48 mV at a current density of 10 mA cm−2, outperforming the noble metal platinum/carbon (Pt/C) catalysts, which required an overpotential of 52 mV. Furthermore, the Ru@Co2P nanoparticles were protected by a carbon layer, preventing catalyst corrosion during long-term operation. The HER performance of the Ru@Co2P/CNFs catalysts remained stable even after 40 h of continuous operation, demonstrating their long-lasting stability. This research introduces a new approach to developing cost-effective and highly active self-supported network-structured phosphide catalysts.

The nanocomposites of nitrile–butadiene rubber (NBR) and organo‐montmorillonite modified by hexadecyltrimethyl ammonium bromide (HMMT) were prepared by the reactive mixing intercalation method in the presence of the resorcinol and hexamethylenetetramine complex (RH). The structure of the NBR–RH–HMMT nanocomposites was characterized by XRD, TEM, FTIR, determination of crosslinking density, and so on. The results showed that the d‐ spacing of HMMT increased substantially with RH addition and the layers of HMMT were dispersed in rubber matrix on a nanometer scale. The mechanical properties of the NBR–RH–HMMT nanocomposites were far superior to those of NBR–HMMT composites, and the glass transition temperature of NBR–RH–HMMT nanocomposite was higher than that of NBR. The reactive mixing intercalation method by introducing RH could enhance the interface combination between the rubber and the organoclay through the interactions of RH with NBR and modified clay. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1905–1913, 2006

We reported the use of an inverse vulcanised polysulfide (SP) as an intelligent interfacial modifier in the NR/CB composites to remarkably decrease the hysteresis loss by enhancing the interfacial adhesion and improving CB dispersion. Specifically, SP synthesized by the bulk copolymerization of sulfur and styrene was grafted onto CB surface by trapping the sulfur radicals generated from SP, and the grafted polysulfides can participate in the crosslinking reaction with NR, which greatly improves CB dispersion and strengthens interfacial adhesion in the composites. As a consequence, the rolling resistance and heat build-up of the modified composites are remarkably decreased, showing great advantages in tire application in term of reducing fuel consumption and extending service life.

Construction of segregated structures in polymer composites is an efficient way to improve the electrical conductivity and reduce the percolation threshold by confining conductive fillers into the interstitial areas between polymer domains. Yet, it remains a great challenge to engineer segregated structures into thermosets as the cross-linked structure prohibits the "sintering" of polymer domains into a coherent material. Thus far, the state of art approaches to create segregated network in cross-linked polymers involve tedious procedures and are limited to latex mixing technology. Here, inspired by solid state plasticity of vitrimers, we present a simple method to create segregated structures in covalently cross-linked networks by compression molding of conductive filler-coated vitrimer granules. Specifically, dynamic boronic ester-cross-linked styrene–butadiene rubber vitrimers was ground into granules and then mechanically mixed with carbon nanotubes (CNTs) to coat CNTs onto vitrimer granules, followed by hot-press molding. During the molding process, the transesterifications of boronic esters enable cross-linked granules to adhere together through molecular bonding, and the high viscosity of granules forces CNTs to selectively localize at their boundary region. As a result, coherently segregated composites with an ultralow percolation threshold, good flexibility, and healing capability are obtained. With this example, we envisage that this work provides a conceptual method to create segregated structures in cross-linked polymers.

Di/polysulfide linkages in vulcanizates can be thermally cleaved to initiate the addition of functional vinyl monomers into rubber skeletons, leading to the formation of functionalized diene-elastomers via dynamic covalent polymerization.

Vitrimers are a class of covalently cross-linked polymers that have drawn great attention due to their fascinating properties such as malleability and reprocessability. The state of art approach to improve their mechanical properties is the addition of fillers, which, however, greatly restricts the chain mobility and impedes network topology rearrangement, thereby deteriorating the dynamic properties of vitrimer composites. Here, we demonstrate that the integration of sacrificial bonds into a vitrimeric network can remarkably enhance the overall mechanical properties while facilitating network rearrangement. Specifically, commercially available epoxidized natural rubber is covalently cross-linked with sebacic acid and simultaneously grafted with N-acetylglycine (NAg) through the chemical reaction between epoxy and carboxyl groups, generating exchangeable β-hydroxyl esters and introducing amide functionalities into the networks. The hydrogen bonds arising from amide functionalities act in a sacrificial and reversible manner, that is, preferentially break prior to the covalent framework and undergo reversible breaking and reforming to dissipate mechanical energy under external load, which leads to a rarely achieved combination of high strength, modulus, and toughness. The topology rearrangement of the cross-linked networks can be accomplished through transesterification reactions at high temperatures, which is accelerated with the increase of grafting NAg amount due to the dissociation of transient hydrogen bonds and increase of the ester concentration in the system.

An advanced elastomer was developed by incorporating a dual-dynamic network into <italic>cis</italic>-polyisoprene, which combines excellent mechanical properties with high self-healing capability.

Sodium deoxycholate (SDC), a kind of bile derivative, is used to noncovalently functionalize graphene. Stable and high concentration (up to 20 mg ml −1 ) of graphene colloid is obtained. The stabilization mechanism is revealed to be hydrophobic interaction, electrostatic repulsion and hydrogen bonding. Single-layer and few-layer graphene are obtained in the colloid. Subsequently, the obtained graphene sheets are incorporated into a polyvinyl alcohol (PVA) matrix by solution casting to fabricate PVA/graphene composites. Morphological observations substantiate the homogeneous dispersion of graphene in the PVA matrix and strong interfacial adhesion between them. Significant improvements in tensile strength and modulus of the composite films are observed.