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Highlights: [•] The synthetic processes of β-cyclodextrin (CD) based functional monomers were improved and characterized in detail. [•] Based on the monovinyl CD based monomer, a new copolymer (PCDs) bearing CD pendants was synthesized and used as superplasticizer. [•] PCDs behaved excellent dispersion ability and strong retarding effect. [ABSTRACT FROM AUTHOR]

Abstract: Comb-like polycarboxylate copolymers (PCs) were synthesized and first used as the dispersants for kaolin suspensions. The apparent viscosity, adsorption behavior, zeta potential, rheological behavior, and TEM images of concentrated kaolin slurries deflocculated with these copolymers were systematically investigated. Sodium acrylate homopolymer (SA) was selected as a reference in order to contribute to the knowledge of how the electrostatic interaction and molecular structure of these copolymers influenced the dispersion, adsorption, and rheological properties of colloidal kaolin suspensions. The results showed that the dispersion of kaolin slurries mainly depended on the synergistic effects of electrostatic interaction and steric hindrance for APEG type comb-like copolymers. PC2 bearing proper carboxylic groups and side chains produced stable dispersion and fluidity in concentrated kaolin slurries. Based on the electrostatic and steric effect of comb-like copolymers, the kaolin slurries displayed a shear thickening behavior, and the Herschel–Bulkley model well described their rheological behaviors. [Copyright &y& Elsevier]

The flexural strength and compressive strength are the two most important parameters that characterize the mechanical properties of cement-based materials, but the two are usually mutually exclusive or negatively correlated. The flexural strength of cement-based materials cannot be effectively improved by a single nanomaterial without reducing their compressive properties. Therefore, compounding various micro–nano materials, fully utilizing their respective advantages, and developing composite materials with new properties and application characteristics are important techniques for enhancing the mechanical properties of cement-based materials. This study aimed to investigate the synergistic enhancement of the mechanical properties of concrete by using microcrystalline cellulose (MCC) and nano-silica (NS) composites. MCC and NS were mixed and modified to synthesize MCCNS materials, which were added to cement slurry for experiments. Results indicated that the flexural strength and compressive strength of the cement paste with MCCNS materials were significantly increased compared with those of the cement pastes without MCCNS or with only NS. The flexural strength of the cement paste with MCCNS-1 was increased by 47%, 20%, 6.3%, and 6.8% after curing for 1, 7, 28, and 56 days, respectively. Meanwhile, compressive strength was also increased by 14.4%, 6.3%, 6.8% and 6.5%, respectively. In addition, the reaction mechanism was speculated through a variety of test results. The addition of MCCNS material facilitated the formation of additional C-S-H, which also contributed to enhancing the mechanical properties of cement paste. • Novel nanocomposites were synthesized using MCC and NS through adsorption-phase reaction and sol–gel methods. • The mechanical properties of cement-based materials were notably enhanced by incorporating MCCNS materials. • The volcanic ash activity of NS led to additional C-S-H formation, improving the mechanical strength of the cement paste. [ABSTRACT FROM AUTHOR]

• Novel organic/inorganic nanocomposites LNTS-1 and CNTS-2 were synthesized from NS and alpha thioctic acid. • Compared with bulk CNTS-2, linear LNTS-1 can effectively improve the macro flexural strength of cement-based materials. • The results of adsorption experiments show that LNTS-1 has strong adsorption on calcium ions. Using organic/inorganic nanocomposites to optimize the microstructures of cement hydration products at the micro/nanometre scale is a promising method for improving the mechanical properties of cement-based materials. One type of novel nanohybrid material modified by the flexible autonomous healing polymer poly-TA (thioctic acid) was synthesized and used as a highly efficient mechanical improvement agent for cement paste. The nanohybrids linear LNTS-1 and bulk CNTS-2 were synthesized from silane-coupled nanosilica and alpha thioctic acid. Due to the existence of hydrogen bonds, coordination bonds and dynamic covalent S S bonds, this type of linear poly-TA with a certain amount of calcium content exhibited good self-healing properties. Linear LNTS-1 can effectively improve the macro flexural strength of cement-based materials without a negative effect on their compressive strength. The flexural strength of cement pastes with 1.0‰ LNTS-1 increased by 11.9%, 15.6%, and 16.9% after curing for 3, 7, and 28 d compared with the control cement paste. The results of adsorption experiments show that nanohybrid LNTS-1 has strong adsorption on calcium ions, which affects the formation of cement hydration products. [ABSTRACT FROM AUTHOR]

A ternary system thermoresponsive hydrogel, poly( N -isopropylacrylamide- co -hydroxyethyl methylacrylate polycaprolactone)/hydroxypropyl cellulose (or P(NIPAAm- co -HEMAPCL)/HPC), was prepared via “alkynyl/azide” click chemistry between the azide modified graft copolymer P(NIPAAm- co -HEMAPCL-N 3 ) and the alkynyl modified HPC (or alkynyl-HPC). The structures of P(NIPAAm- co -HEMAPCL-N 3 ) and alkynyl-HPC were characterized by 1 H NMR, SEC and FT-IR, and the results demonstrated that the mole ratio of the alkynyl and azide functional groups, and the feed ratios of HPC, PCL, and PNIPAAm could be easily adjusted. The incorporation of PCL and HPC dramatically enhanced the compression modulus of the P(NIPAAm- co -HEMAPCL)/HPC hydrogel, which ranged from 500 to 1000 g/cm 2 . Due to the immiscibility of HPC and PCL, a heterogeneous and semicontinuous structure was observed via SEM. The incorporation of HPC accelerated the water absorption rate and enhanced the hydrogel's ability to shed water. The swelling–deswelling and compressive properties could also be adjusted by changing the feeding ratio. The hydrogel exhibited reversible swelling–deswelling behavior after three “swelling–deswelling” cycles. [ABSTRACT FROM AUTHOR]

Abstract: A novel Eu-complex Eu(TTA)2vinyl-phen has been designed and synthesized via simple reaction as an efficient fluorescent sensor for F−, CH3COO−, and H2PO4 −. The anion-sensitivity of Eu-complex was evaluated using a series of anion in DMSO solution. On binding with F−, CH3COO−, or H2PO4 −, fluorescence quenching of Eu-complex was easily observed, while no obvious fluorescence change could be observed in the presence of other anions. More importantly, the Eu-complex exhibited excellent selectivity and sensitivity for F− and H2PO4 − in water/DMSO (5/5) solution. The titration results of UV–vis, fluorescence, and 1H NMR spectra indicated that the fluorescence quenching can be attributed to the strong hydrogen bonding interaction between anions and imidazole group of Eu-complex. To meet application requirements for biological and environmental detection in water, we successfully prepared a Eu-based fluorescent hydrogel probe using Eu(TTA)2vinyl-phen and N-isopropyl acrylamide (NIPAAm) as monomers through free radical copolymerization in DMF. Emission spectra titration experiments indicated that this hydrogel probe can effectively recognize H2PO4 − (detection limit 10−5 M), but cannot recognize F− and CH3COO− in pure water. To the best of our knowledge, this is first report that Eu-based fluorescent hydrogel probe for H2PO4 − detection in pure water. In addition, the emission of Eu-complex is also found to be sensitive to molecular oxygen through energy back-transfer mechanism. [Copyright &y& Elsevier]