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3 Composites Prepared by Dip-Drawing Method
Published in Mahmood Aliofkhazraei, Advances in Nanostructured Composites, 2019
Fluorescent PS latexes were produced via emulsion polymerisation process (Liu et al. 1994). The polymerisation was performed batchwise, using a thermostated reactor equipped with a condenser, thermocouple, mechanical stirring paddle and nitrogen inlet. Water (50 mL), styrene monomer (3 g; 99% pure from Janssen) and 0.014 g of fluorescent 1-Pyrenylmethyl methacrylate (PolyFluor 394) were first mixed in the polymerisation reactor where the temperature was kept constant at 70°C. The water soluble radical initiator potassium persulphate (1.6% wt/wt over styrene) which dissolved in a small amount of water (2 mL) was then introduced in order to induce styrene polymerisation. Different surfactant sodium dodecyl sulphate concentrations (0.03 and 0.12% wt/vol) were added in the polymerisation recipe to change the particle size keeping all other experimental conditions the same. The polymerisation was conducted under 400 rev.min−1 agitation during 12 h under nitrogen atmosphere at 70°C. The particle size was measured using Malven Instrument NanoZS. The mean diameter of these particles is 203 nm (SmPS) and 382 nm (LgPS). The weight average molecular weights (Mw) of individual PS chain (Mw) were measured by gel permeation chromatography and found to be 90 × 103 g.mol−1 for both 203 nm (SmPS) and 382 nm (LgPS). Glass transition temperature (Tg) of the PS latexes were determined using differential scanning calorimeter and found to be around 105°C.
Environmental Aspects and Analysis of Phenols in the Aquatic Environment
Published in B. K. Afghan, Alfred S. Y. Chau, Analysis of Trace Organics in the Aquatic Environment, 2017
Reagents Buffered 4-aminoantipyrine (4-AAP) solution: Dissolve 27 g potassium bicarbonate (KHCO3), 27 g boric acid (H3B03), and 35 g potassium hydroxide (KOH) in approximately 750 ml distilled water and dilute to 1 1. Dissolve 2.1 g 4-aminoantipyrine, C11H13N,O, in this buffer solution. Prepare daily.Potassium persulfate solution, 2.5%: Dissolve 25 g potassium persulfate, K2S2O8, in distilled water and dilute to 1 1. Adjust the pH to approximately 11 with potassium hydroxide. Prepare daily.Wash solution: Dissolve 1 g copper sulfate, CuSO4-5H2O, in distilled water. Add 2 ml phosphoric acid, H3P04, and dilute to 1 1 with distilled water. Approximately 6 1 of wash solution is required daily.Phenol stock solution, 1000 mg/1: Dissolve 1.00 g phenol, C6H5OH, in distilled water (phenol-free) and dilute to 1 1. Preserve with copper sulfate solution and store in a dark bottle in the refrigerator. Prepare weekly.Phenol intermediate solution, 10 mg/1: Dilute 10 ml of phenol stock solution (7.4) to 1 1 with distilled water containing copper sulfate and phosphoric acid in the same proportions as in the wash solution (7.3). Phenol standard solution, 0.10 mg/1: Dilute 10 ml of intermediate solution (7.5) to 1 1. Preserve with copper sulfate solution.Phenol working standards: Prepare a series of working standards in the required concentration range by appropriate dilutions of the standard solution (7.6). Prepare daily. Preserve with copper sulfate solution.
Inhibition Characteristics of Gel-Based TiO2/OPC/CPAAM Composite Inhibitor to Control Coal Spontaneous Combustion
Published in Combustion Science and Technology, 2023
Zhian Huang, Hao Ding, Chuanwu Sun, Zhiwei Tan, Guanhua Wang, Yinghua Zhang, Pengfei Wang, Sainan Quan, Xinhui Zhao
Graft copolymerization is mainly composed of three primary reactions: chain initiation, chain propagation, and chain termination (see Figure 2). During the chain initiation reaction, the initiator potassium persulfate is decomposed. The resulting primary radicals can break the bond between C2 and C3 in the chitosan molecule and the phenolic hydroxyl bond in the procyanidins molecule. During the chain propagation reaction, potassium persulfate can trigger the generation of free radicals from acrylic acid and acrylamide, which can be grafted onto chitosan molecules. Under the action of a crosslinking agent, each monomer can be rapidly grafted and copolymerized to form longer carbon chains and larger polymer molecules. At the chain termination stage, the polymer molecule includes the main chain, side chain, and highly cross-linked three-dimensional network structure. These features indicate that the polymer gel has been prepared.