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The graft polymer Dex-g-PSSS was obtained through poly(sodium 4-styrene sulfonate) (PSSS) grafted on dextran(Dex) by using the cerium salt-hydroxyl group redox initiation system. The cross-linked microspheres C(Dex-g-PSSS) were synthesized by suspension polymerization with epichlorohydrin as the cross-linking agent. The chemical structure and physicochemical characteristics of C(Dex-g-PSSS) microspheres were represented by infrared spectroscopy (FTIR), optical microscope, and zeta potential analysis. The aim of the study is to constitute a colon-specific drug delivery system via molecular design, using C(Dex-g-PSSS) microspheres as the drug-carrying material and taking 5-fluorouracil (5-FU) as the model drug. The drug-carrying ability and mechanism of the cross-linked microspheres C(Dex-g-PSSS) for 5-FU were investigated. Finally, in vitro release tests for the drug-carrying microspheres were conducted. The experimental results show that in the medium with pH 2, the cross-linked microspheres C(Dex-g-PSSS) exhibit a strong adsorption ability for 5-FU because of strong electrostatic interactions and have an adsorption capacity of 154 ± 7.5 mg/g, displaying high drug-carrying efficiency. The in vitro release behavior of the drug-carrying microspheres is highly dependent on pH and dextranase. In the medium with pH 2, the drug-carrying microspheres do not release the drug and in the medium with pH 1, they release a little, whereas in the medium with pH 7.4, a sudden delivery phenomenon of the drug will occur, and in the presence of dextranase, a more sudden delivery phenomenon of the drug will occur, displaying an excellent colon-specific drug delivery behavior.

Considering the recent eco-friendly and efficient utilization of three kinds of solid waste, including calcium silicate slag (CSS), fly ash (FA), and blast-furnace slag (BFS), alkali-activated cementitious composite materials using these three waste products were prepared with varying content of sodium silicate solution. The hydration mechanisms of the cementitious materials were analyzed by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy. The results show that the composite is a binary cementitious system composed of C(N)-A-S-H and C-S-H. Si and Al minerals in FA and BFS are depolymerized to form the Q0 structure of SiO4 and AlO4. Meanwhile, β-dicalcium silicate in CSS hydrates to form C-S-H and Ca(OH)2. Part of Ca(OH)2 reacts with the Q0 structure of AlO4 and SiO4 to produce lawsonite and wairakite with a low polymerization degree of the Si-O and Al-O bonds. With the participation of Na+, part of Ca(OH)2 reacts with the Q0 structure of AlO4 and the Q3 structure of SiO4, which comes from the sodium silicate solution. When the sodium silicate content is 9.2%, the macro properties of the composites effectively reach saturation. The compressive strength for composites with 9.2% sodium silicate was 23.7 and 35.9 MPa after curing for 7 and 28 days, respectively.

In order to realize high-value utilization of calcium silicon slag (CSS) and silica fume (SF), the dynamic hydrothermal synthesis experiments of CSS and SF were carried out under different hydrothermal synthesis temperatures. In addition, phase category, microstructure, and micropore parameters of the synthesis product were analyzed through testing methods of XRD, SEM, EDS and micropore analysis. The results show that the main mechanism of synthesis reaction is that firstly β-Dicalcium silicate, the main mineral in CSS, hydrates to produce amorphous C–S–H and Ca(OH)2, and the environment of system is induced to strong alkaline. Therefore, the highly polymerized Si-O bond of SF is broken under the polarization of OH− to form (SiO4) of Q0. Next, amorphous C–S–H, Ca(OH)2 and (SiO4) of Q0 react each other to gradually produce various of calcium silicate minerals. With an increase of synthesis temperature, the crystal evolution order for calcium silicate minerals is cocoon-like C–S–H, mesh-like C–S–H, large flake-like gyrolite, small flake-like gyrolite, petal-like gyrolite, square flake-like calcium silicate hydroxide hydrate, and strip-like tobermorite. In addition, petal-like calcium silicate with high average pore volume (APV), specific surface area (SSA) and low average pore diameter (APD) can be prepared under the 230 °C synthesis condition.

Calcium silicate slag (CSS) is used as a secondary solid waste produced by aluminum extraction technology from high alumina fly ash, and its resource utilization has always been a key issue to be solved. In this study, CSS was used to replace a portion of fly ash (FA) to prepare a new inorganic binder stabilized material for road base. The unconfined compressive strength (UCS), phase composition, microstructure, durability and performance index of the base of the test section of the CSS pavement base material were studied. The results showed that with the increase in CSS content, the UCS of pavement base materials gradually increased. Under standard curing conditions, the UCS increased 6.90~17.24% after 7 days, and 7.90~28.95% after 28 days. The main reason was that as the hydration time increased from 7 d to 28 d, the hydration products C-A-S-H gel and C-S-H gel increased, the [SiO4] polymerization degree increased, the crystal type changed, and the structure denser, which supported the good development of mechanical strength of CSS pavement base material. In addition, the research has been successfully applied to a pilot test in Hohhot, China. The freeze–thaw resistance, water stability and UCS of the CSS pavement base material were tested to meet the requirements of Chinese road construction standards, indicating that the application of CSS in pavement base is feasible.