Materials Science Forum Vol. 953

Abstract: The quality stability of the natural rubber is a key point to its use in the industries and some special fields. However, due to storage hardening caused by the complicated molecular structure of natural rubber and non-rubber component, the quality uniformity is still not controlled in the nowadays rubber factory. In the previous research, storage hardening phenomena are extensively examined but the special mechanism is controversial and detail information is need to be further revealed. The dynamic evolution of accelerated storage properties and molecular structure of natural rubber have been investigated. The results show that △P increased slowly at first but then increased apparently and PRI has no direct relationship with △P. The storage time of 24 h is the critical storage period in which besides the △P and PRI, the P₀, gel content and molecular weight also has obvious transformation. △P has a negative apparent correlation with ester content but protein content is relatively of no account in storage hardening process.

Abstract: A new type of polymer emulsion was prepared by the copolymerization of DAAM and VAc monomer with high solid content and storage stability. By addition of ADH (ketonic hydrazide cross-linking reaction), the polymer emulsion can be cross-linked at room temperature. It was found that the degree of cross-linking of the polymer reaches 71.85%, and the resistance to boiling water reaches 180min at the maximum of DAAM of 2% and DAAM / ADH = 1/1.

Abstract: The ampholytic surfactant Lauramidopropyl betaine (LAB) is a multifunctional amphoteric surfactant, which is widely used in washing formulations and is the main component of many softeners and detergent formulations. It has the advantages of less irritation to skin, mild performance and easy biodegradability. It is superior to other amphoteric surfactants. In this paper, new surfactants were synthesized by using LAB as the main component and the molar ratios of LAB to formaldehyde were 1:1, 1:2, 1:3 and 1:4, respectively. The new functional group hydroxymethyl was introduced into the LAB, and the effect of hydroxymethyl on the properties of raw materials was discussed. And the surface properties were studied, including high temperature resistance, methanol resistance and salt resistance. The results showed that the high temperature resistance of R2 is better below 50 °C, R0 has better high temperature resistance above 50 °C; In the aspect of methanol resistance, the methanol resistance of R4 is better at 10% and 20% methanol content; The effect of R0 is better in salt resistance. Finally, it can be concluded that the introduction of methylol groups improves the performance of the prepared new surfactants in certain properties.

Abstract: The ampholytic surfactant lauramidopropyl betaine (LAB) has excellent properties and very low irritation. It has good compatibility and can be used together with cationic, anionic and nonionic surfactants. In this paper, new surfactants were synthesized by using LAB as the main component and the molar ratios of LAB to formaldehyde were 1:1, 1:2, 1:3 and 1:4, respectively. The new functional group hydroxymethyl was introduced into the LAB, and the effect of hydroxymethyl on the properties of raw materials was discussed. And the surface properties were studied, including surface tension, critical micelle concentration and foaming ability. Finally, it can be concluded that the introduction of methylol groups improves the performance of the prepared new surfactants in certain properties.

Abstract: Fluorescent detection is a practical kind of methods to use in heavy metal ions detection technology. Carbonized Polymer Dots (CPDs) is good carbon-like material with low toxicity, green, ion-response. In this work, we successfully synthesized a yellowing fluorescent CPDs from folic acid. The luminescence intensity of CPDs decreased with the increase of copper ion content, and the detection limit was 0.44ppm.

Abstract: In order to solve the problems of wax deposit, this study evaluated the effect of wax cleaning agent used in Changqing and adjusted its formulation. The results showed that the wax removal rate of oil based dewaxing agent was slightly higher than that of emulsion dewaxing agent for crude oil with low salt content. It is possible that the emulsion dewaxing agent contains a certain amount of mutual solvents, which improves its wetting ability at the oil-water interface and makes the oil and water dissolve each other. So that the wax deposit surface from hydrophilic hydrophobic to hydrophilic hydrophobic, forming anti-wax film to prevent wax deposition. Therefore, the wax removal ability of 1#, 3# oil wax is higher than that of oil base wax dewaxing agent.

Abstract: Ni/Cu/Fe mixed metal oxides (Ni/Cu/Fe-MMOs) were prepared by calcination of Ni/Cu/Fe layered double hydroxides (Ni/Cu/Fe-LDHs) precursors. Their composition, structure and morphology were characterized by ICP, XRD, FT-IR, BET and SEM. Ni/Cu/Fe-MMOs were used for catalytic removal of NOx by hydrocarbon. Their catalytic activities were studied by NOx analyzer. The results show that Ni/Cu/Fe-MMOs have homogeneous distribution of hexagon with particles size around 30~50nm and specific surface areas of 10~35 m²∙g^–1. Ni/Cu/Fe-MMOs sample with molar ration of Ni/Cu/Fe = 5:1:3 exhibits the highest NOx conversion of 15.3%. Ni/Co/Cu/Fe-MMOs have better catalytic activities than both Ni/Cu/Fe-MMOs and Cu/Co/Fe-MMOs. For Ni/Cu/Fe-MMOs, propene is the better reductant than octane.

Abstract: Using 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10 oxide (DOPO) and N-methylol acrylamide as the main raw materials, the curing agent DOPO-NMA was synthesized. The flame retardant curing agent DOPO-NMA and E-51 epoxy resin (EP) were then cured to obtain epoxy resin E-51 system, and its flame retardancy, thermal stability and mechanical properties were studied. The results showed that the tensile, bending and impact strength of the cured system decreased with the increase of phosphorus mass fraction in the resin system, and the flame retardancy rating, limiting oxygen index (LOI) and char yield at 700°C increased with the increase of phosphorus mass fraction in the resin system.

Abstract: A new phosphorus-containing flame-retardant curing agent PPDTA was synthesized from phenylphosphonic dichloride (PPD) and 3-amino-1,2,4-triazole (TA) in tetrahydrofuran solvent to improve the flame retardancy of epoxy resin. The structure of the compound was analyzed and confirmed by infrared spectroscopy. The effects of reaction time, reaction temperature and ratio of reactants on yield were studied by using three-factor three-level orthogonal experiment. The results show that the yield of PPDTA can reach 86.4%, when the reaction time is 10h, reaction temperature is 70 °Cand the molar ratio of TA to PPD is 2.2:1.

Abstract: Silica fibers were prepared from the agricultural waste-rice straw via a slow calcination process. A possible formation mechanism of the obtained silica fiber was explained. The phytoliths/vascular composite fibers of rice straw work as the structural directing templates for the formation of silica fibers under the slow calcination process. Owing to the potassium silicate active site, the separable silica fiber showed great capability in removal of Cu²⁺, Ni²⁺, Cd²⁺ and Pb²⁺ from aqueous solution with efficiency higher than 99%. Additionally, over 90% of equilibrium adsorption capacity can be reached within 10 minutes, showing the easily accessible paths and active sites for ion transportation and adsorption in the as-prepared fiber. These results of this work are beneficial for scientists pursuing new synthetic route for valuable and widely applicable silica fiber materials from the agricultural waste, also helping to solve disposal of the agricultural waste and pollution problems.