Yixing Zhan,Yating Wang,Ming Wang,Xiaoqing Ding,Xinlong Wang
The nano metal–organic framework particles (nano ZIF-8) are grafted onto the surface of short carbon fibers (SCFs) by a facile in situ growth method in order to functionalize SCFs. The morphology, crystal structure, and chemical element composition of modified SCFs (ZIF-8@SCFs) are investigated. The grafted nano-ZIF-8 could remarkably enhance the roughness, polarity, and wettability of SCFs surface and promote the curing reaction of epoxy composites. The tensile strength, flexural strength, elastic modulus, toughness, and impact strength of the epoxy composites with 1 wt% ZIF-8@SCFs are increased by 25%, 31%, 51%, 28%, and 42% compared to that of the composites with 1 wt% SCFs, respectively. Furthermore, the storage modulus ( E ′) and glass transition temperature ( T g ) are enhanced from 2558 MPa and 108.2 °C to 3000 MPa and 147.6 °C. The significant improvement in mechanical and thermomechanical properties of the prepared composites could be ascribed to the ameliorated wettability, enhanced mechanical interlock, and increased chemical bonding induced by ZIF-8@SCFs.
Yang Shuquan,Wang Yating,Li Huazheng,Zhan Yixing,Ding Xiaoqing,Wang Ming,Wang Xinlong,Xiao Leqin
p -Hydroxybenzoic acid is an emerging contaminant because it has multiple sources such as the hydrolysis of methylparaben, ethylparaben and propylparaben used widely as preservatives in food and drinks, and as well as from the agro-industrial wastewaters. In this study, the nano-ZIF-8@chitosan microspheres (ZIF-8@CSM) were fabricated via the combination of inverse emulsion method and in-situ growth method. The performance of ZIF-8@CSM for the adsorption of p -hydroxybenzoic acid from aqueous solution was studied. The adsorption kinetics showed that the adsorption rapidly reached the equilibrium about 30 s. The equilibrium data were well described by the Langmuir isothermal model and the estimated maximum adsorption capacity was 128.70 mg/g. The thermodynamics analysis indicated negative free energy, enthalpy, and entropy changes suggesting that the adsorption process was spontaneous and exothermic. ZIF-8@CSM is promising to be used as a good adsorption material to remove p -hydroxybenzoic acid rapidly from aqueous solutions.
Linna Zhong,Junyu Chen,Zhiyong Ma,Hao Feng,Song Chen,He Cai,Yiyuan Xue,Xibo Pei,Jian Wang,Qianbing Wan
Bone substitute biomaterials, whose compositions and structures both play vital roles in bone defect healing, hold promising prospects in the clinical treatment of bone defects. Three-dimensional (3D) printed porous scaffolds incorporating osteoinductive components are considered as ideal bone grafts, because of the accurate control of structure parameters and the capacity to enhance bone tissue regeneration. Our previous studies demonstrated that nanoscale zeolitic imidazolate framework-8 (nanoZIF-8), a subclass of metal organic frameworks (MOFs), presented minimal cytotoxicity, inhibited bacterial activities, and promoted osteogenesis both in vitro and in vivo. However, the application of nanoZIF-8 in the 3D printed scaffold system remains unknown. In this study, nanoZIF-8 was incorporated into composite scaffolds composed of polycaprolactone (PCL) and dicalcium phosphate dihydrate (DCPD) via extrusion-based 3D printing technology. The results revealed that the composite scaffolds possessed increased mechanical strength and exhibited homogeneous structure with highly interconnected macropores. In vitro studies indicated that scaffolds showed biocompatibility to bone mesenchymal stem cells (BMSCs), significantly up-regulated the expression of osteogenesis-related genes and proteins, and facilitated the extracellular matrix mineralization. In vivo results showed that 3D printed porous scaffolds promoted new bone formation and enhanced micro-architecture at the critical defect sites (Φ10 mm) in rabbits, compared with the blank control group. Moreover, composite scaffolds significantly improved calvarial defect healing in comparison with scaffolds without nanoZIF-8 incorporation. In summary, nanoZIF-8 modified 3D printed porous composite scaffolds demonstrated great potential in the treatment of critical-sized bone defects, proving the effectiveness of MOF incorporation in 3D printed composite scaffolds to promote osteogenesis in the field of bone tissue engineering.
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