In this study, Metakaolin was used as source material, NaOH and sodium silicate were used as alkali activators.Preparation of three sets of geopolymer samples subject different NaOH concentration from 8 to16mol/L. The effect of alkaline concentration on compressive strength was analyzed. NaOH concentrations at 12mol/L and 16mol/L resulted in high 7-day compressive strengths. And the compressive strength of geopolymeric cement reached the maximum when adding 24mL sodium silicate at SiO2:Na2O ratio 3.3.
Properties of corn starch dissolved in NaOH/urea aqueous solutions were studied in this research, and NaOH/urea at different ratios in aqueous system was used to treat corn starch (CS). NaOH/urea breaks down the structure of CS, resulting in chemical degradation. After degradation, the change of molecular weight was analyzed by GPC-MALLS. The degraded CS (DS) and native CS(NS) were grafted with acrylic acid and compared in FTIR and both DS and NS were successfully grafted with AA.
The corrosion of stainless steel was experimentally investigated and analyzed to improve the service-life of the crucible and fi xture clamps. Through the experiment, stainless steel was found to satisfy the crucible and fi xture clamps materials. As the chromium element mass percentage of the stainless steel increased, the corrosion decreased rapidly at first and then slowly increased. With the corrosion time prolonging, the corrosion growth rate is generally a downward trend. With Chromium 20%, the corrosive were the least. With Nickel element mass percentage increased, the corrosion increased rapidly at fi rst and then decreased rapidly, fl atten at the last. It was special that the corrosion had little relationship with the Chromium and Nickel mass percentage when the Nickel percentage is more than 35%. The most remarkable corrosion is corresponding with the Nickel element 12%, the least corrosion with Nickel element 80%. So Nickel element 35% is the most optional.
Ethyl cellulose (EC) was grafted with phthalic anhydride (PA) by esterification reaction without any catalyst in ethanol-methylbenzene mixture. The chemical structure and thermal stability of grafted copolymer (EC-g-PA) were analyzed by FT-IR and TGA, respectively, and compared with those of EC. The FT-IR results showed that EC has been grafted successfully with PA and the TGA results also show different thermal behavior between EC and EC-g-PA.
A pH-sensitive semi-interpenetrating polymer network (semi-IPN) hydrogel based on Konjac glucomannan(KGM) and methylacrylic acid(MAA) was prepared by free radical polymerization at different concentrations of initiator potassium persulfate (KPS) in presence of crosslinker N,N-methylene-bis-acrylamide (MBA). The chemical structure and rheological properties of hydrogels were characterized by FT-IR and rheometry, respectively. In addition, the swelling behavior of the hydrogels were studied in buffer solution at different pHs.
The micro-structure of the surface of Hevea brasiliensis latex particles has been found by the means of atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), and electrokinetics over a broad range of KNO3electrolyte concentrations (4-300 mM) and pH values (1-8). Based on the atomic force microscopy analysis of the fresh natural rubber latex, it could be estimated that the protein-lipid layer is covered with the rubber particles. The molecules in the particle were labeled with fluorescent Rhodamine (RB), and were monitored by CLSM. SEM and TEM were used to observe the surface of fresh natural rubber particles and were dyed by osmium tetroxide. Fourier Transform Infrared Spectroscopy (FTIR) has been used to characterize the nitrogenous groups in natural rubber and deproteinized natural rubber (DPNR). The FTIR and1H-NMR analysis of phosphatase-treated DPNR confirmed that the presence of mono- and diphosphate terminations without phospholipids was also unlikely owing to the presence of a methylene proton signal of an isoprene unit linked to mono- and diphosphate groups. The , [η] and Higgins’ k’ of DPNR decreased after being treated with lipase.
Rice husk is a plentiful agricultural byproduct. In this paper, rice husk (RH) surface was first treated by NaOH/urea into a modified-rice husk(MRH), then the MRH was used as a new template for polymerization of acrylamide(AM) on MRH, as a result, the product named as MRH-g-AM, was formed by the free-radical initiation in aqueous solution using ammonium persulfate as an initiator. The polymer grafted on the MRH was considered as a novel copolymer which was thereafter analyzed by FTIR and SEM. The product was washed thoroughly with distilled water to remove all unreactive chemicals. The results showed that MRH was successfully reacted with AM. The SEM images indicated that MRH-g-AM appeared distinct cracks and formed a loosen structure in comparison with RH, indicating the facilitation of heavy metal ion adsorption in the future wastewater treatment.
D-glucose was used to react with methyl methacrylate (MMA) (and methyl acrylate(MA) as comparison) to generate new biomass-based materials in presence of free radical initiator. Potassium peroxydisulfate was used as free-radical initiator in the reaction. The final chemical structure and thermal stability were analyzed by FT-IR and TGA. The results showed that the Glucose-co-MMA (G-MMA) and Glucose-co-MA (G-MA) copolymers had better thermal performance than PMMA and PMA.
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