A green and high-efficiency method was developed to prepare low-cost and high-quality graphene on a large scale through direct exfoliation of graphite in aqueous media using tannic acid (TA) as the stabilizer. The influence of preparation parameters on graphene concentration (C G ) and graphite exfoliation efficiency (C G /C G,i ), including TA concentration (C TA ), initial graphite concentration (C G,i ), pH, ionic strength, sonication time, and cycles, was systematically investigated. Under the optimum conditions, the highest C G that can be attained is 1.25 mg•mL −1 with C G /C G,i equal to 2.5%, and 92% of the as-formed graphene are few-layer graphene (below 5 layers) with the electrical conductivity as high as 488 S•cm −1 . Due to TA on the graphene surface acting as the dual roles of dispersant and interfacial regulator, the high-quality graphene can be uniformly dispersed and tightly integrated into polymer matrices for high-performance and multifunctional polymer nanocomposites. In a word, this contribution provides a simple, green, high-efficiency, and scalable avenue for mass production and utilization of highquality graphene.

Elastomer foams based on EVA, PU, and EVA/PU blends formulated for shoe-sole applications were prepared by a supercritical N 2 batch foaming process and characterized for physicomechanical, friction and abrasion properties. The blending of EVA with PU was aimed for improving the friction and wear characteristics of the EVA based foams. All of the foams prepared showed spherical cells with closed-cell morphology and the cell sizes varied with varying the EVA/PU blend ratio and CaCO 3 content of the foams. The properties such as hardness and resilience, friction coefficients and abrasion resistance improved for the EVA/PU blend foams compared to the EVA foam, but their compression set, tensile strength, and tear strength were inferior to the EVA foam. The incorporation of CaCO 3 filler increased density, hardness, tensile strength, and tear strength of the EVA/PU blend foams but decreased resilience, compression set, friction coefficients, and abrasion resistance. The improvement in friction coefficients and wear resistance obtained in the EVA/ PU blend foams was significant for shoe-sole applications. POLYM. ENG. SCI., 58:673-682, 2018.

This paper proposes a new technique for the preparation of foamed Eucommia ulmoides gum (EUG)/high-density polyethylene (HDPE) shape memory composites and establishes the relationship between structures and properties in foamed shape memory composites. Eucommia ulmoides gum/HDPE shape memory composites are designed to memorize 2 temporary shapes by exploiting the different melting points of the 2 phases; the triple shape memory effect in the composites is investigated via mechanical measurements, thermal analysis, and shape memory behavior analysis. The results show that HDPE phase enables the composites to effectively memorize the first temporary shape and EUG phase contributes the second temporary shape. When the ratios of EUG and HDPE were 80/20 and 70/ 30, the composite exhibited satisfactory shape memory behavior with favorable shape fixity ratio and shape recovery ratio, in addition to excellent mechanical properties (tensile strength of 15 MPa, tear strength above 51 KN/m, and foam porosity of about 11%).

Shape memory materials are a type of smart material with potential applications in sensors, textiles, aerospace engineering and medical devices. In this study, we prepared Eucommia rubber and high density polyethylene (HDPE) composites with co-continuous architecture by a simple physical blending method. The shape memory composites memorized two temporary shapes using different melting points of natural Eucommia rubber and HDPE with the addition of dicumyl peroxide (DCP). The architecture of Eucommia rubber/HDPE composites is critical to the materials' properties: each component forms a three-dimensional percolating network and good properties of the two components may be synergically combined. Our results showed that the memory behavior of the composites was dependent on the degree of crystallinity in the composites. When the DCP was 1 phr, the physical and mechanical properties of the Eucommia rubber/HDPE composites improved and exhibited excellent shape memory behavior, with better values of the shape fixity ratio than of the shape recovery ratio. When DCP was 6 phr, the crystalline phase of Eucommia rubber in the composites was almost completely destroyed, which resulted in one temporary shape memory behavior of the composites.

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