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This study proposes a green, low-cost, and robust method to synthesize spherical calcium hydroxide (CH) nanoparticles based on the co-precipitation of Ca2+ and OH− in the presence of tannic acid (TA), an inexpensive plant-derived polyphenol. It has been found that the morphology and crystalline phase of the produced CH nanoparticles can be controlled by TA. With the increasing dosage of TA, the crystallinity of the CH particles reduces, changing from well crystallization to amorphous phases. Experimental evidence suggests that complexion reaction took place between TA and Ca2+, which gave the Ca2+ a strong bond effect. As a result, the nucleation and growth of CH were significantly affected. CH nanoparticles with sizes of about 50 nm have been successfully synthesized by using 0.3% or more TA.

Normal-strength concrete is widely used in construction sites considering the cost, technology, and structural safety. The ecological upgrade of such materials is more meaningful for the sustainable development in a greener way. To this end, the feasibility of ecological upgrade of normal-strength mortars (NSM) by using high volume of ground granulated blast furnace slag (GGBS) (70%–90%) was evaluated in this paper. Comprehensive experiments were conducted to investigate the influences of experimental variables such as content of cement, curing temperature, and mass ratio of water to binder (w/b) on the fresh properties, compressive strength, hydration products, microstructure, and pore structure of NSM. Ecoefficiency evaluation was conducted based on the energy requirement for the whole production of cement and GGBS. Experimental results showed that ecological upgrade of NSM was viable and feasible. When substituting 70% to 90% cement by GGBS, the energy requirement of 1 t binder can be accordingly saved by 67% to 86%, and the performance energy can be reduced from 25.4 (kWh/t)/MPa to 6 to 8 (kWh/t)/MPa. With proper contents of GGBS (70% or 75%), the 28 d compressive strengths were acceptable with reductions less than 10%. Evaluated curing temperatures and decreased w/b were viable methods to promote the early-age compressive strength of NSM incorporating high volume of GGBS. For instance, raising the curing temperature to 40°C can help achieve higher early-age compressive strength than that of the control group. In addition, the pore sizes within ZII (

High-performance poly(lactic acid) (PLA) foam has been recognized as a promising material because of its biodegradability. However, low flexibility and foamability of PLAs has limited its use in different fields. In this study, a blend-toughening technology was used to toughen PLA and prepare flexible foams. The mechanical properties of PLA blends were evaluated, and the cellular structure of these foaming blends was characterized. The results show that the blending components significantly affected the overall mechanical properties and foaming behavior of PLA. The toughness of PLA was enhanced by adding poly(butylene adipate- co-terephthalate) (PBAT) and rigid particles. The rheological behavior of PLA was also affected by adding PBAT. Therefore, the cellular structure of the PLA foams was affected. A constitutive model was also used to fit the experimental results of the compression property of the PLA foam.

Foams of poly(lactic acid) (PLA)/octa(epoxycyclohexyl) polyhedral oligomeric silsesquioxanes (ePOSS) composite were prepared by melt-mixing and solid-state foaming methods. A systematic and accurate method was applied to evaluate the effects of epoxy-based POSS on the structure of dispersion, thermal behavior, and rheological properties of PLA composites. The application of secondary electron–electron back-scattered diffraction technique was used to observe the cellular micromorphology and micro-phase dispersion in composite foams, simultaneously. The results indicated that secondary dispersion of POSS aggregates occurred in foaming process. The enhanced melt elasticity, dispersity of POSS, and crystallization morphology of PLA/POSS composite had a significant effect on the controlling foaming behavior. Thus, a homogeneous and finer cellular morphology of PLA/POSS composite foam with high expansion ratio was obtained with a proper content of POSS in the composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46399.