Papers by Author: Guo Zheng

Abstract: Lubricant base oil is an environmentally friendly lubricant with good lubricity and biodegradability. The thermostability and stability of rapeseed oil get improved through chemical modification. Fatty acid methyl ester (FAME),prepared by rapeseed oil as starting material with methanol by transesterification,the composition of FAME was detected by gas chromatograph-mass spectrometer (GC-MS).Trimethylolpropane (TMP) esters of fatty acids were synthesized by transesterifying FAME with TMP using zinc oxide as catalyst. The structures of products were characterized by mean of FTIR. The reaction conditions were studied and optimized, the optimum conditions were as follows: the temperature at 140°C~150°C, the reactant mass ratio of 1:9, the reaction time for 6 h, the mass content of catalyst of 0.5%.The thermal stability of product was conducted by thermogravimetry (TG) .It could be concluded that TMP esters of fatty acids possess better thermal stability.

Abstract: Boric acid and glycerol were adopted as the starting materials to react with cation exchange resin (CER) as the catalyst. The conversion of the products was characterized by acid value, titrated by potassium hydroxide (KOH) ethanol solution. It showed that the yield of the optimum products got to about 89%. Then they were modified with EO, gaining more than four carbon chains, and hydrolytic time was prolonged to 48 h. The structures of the unmodified and modified products were further confirmed by IR. The results indicated that hard hydrolytic borate ester surfactants with C-O-C bond were synthesized.

Abstract: In this article, acrylic fiber which was from factory production lines was chosen as samples. The method consisted of extraction of Diethyl Formamide (DMF) via using solid-liquid extraction technique and Gas Chromatograph (GC) analysis. DMF in acrylic fiber were extracted by distilled water, separated though DB-17 capillary column and detected by Flame Ionization Detector (FID). By means of external standard method quantitative analysis was accurately investigated. Detection limit was 3 ppm and recovery rate of DMF was in the range of 94% and 98%. These results showed that this test method was of high precision and sensitivity, which achieved the enterprise production requirements.

Abstract: Polyurethane (PU) prepolymer with the isocyanine-based were synthesized by toluene -2, 4-diisocyanate (TDI), polyethylene glycol (PEG-400) and polyethylene glycol (PEG-1000) with N-methylpyrrolidone as the solvent. The effects of temperature and time on the synthesis of polyurethane prepolymer were examined in this paper. The structures of PU, unmodified epoxy resin and modified epoxy resin were identified by FI-IR spectra. It was shown that polyurethane prepolymer was synthesized at 70°C for 5 hours and modified epoxy resin was synthesized successfully.

Abstract: Amino silicone (PDMS) with lower viscosity were synthesized at a certain temperature by ring opening copolymerization of octamethylcyclotetrasiloxane (D4), N-β-aminoethyl-γ- aminopropyl methyl dimethoxysiloxane (YDH-602), hexamethyldisiloxane (MM) with KOH as catalyst and DMSO as accelerating agent. The chemical structure was characterized via IR and 1HNMR. And the important factors were investigated carefully and the best technology of synthesis was obtained: reaction temperature 100-110°C, time 3h, KOH 0.05%, DMSO 0.5% and MM 5-7%, distilling at 110°C/0.095Mpa for 40 min.

Abstract: In this paper, borate ester had been synthesized by the raw materials glycerol and boric acid. The hydrolytic stability of borate ester was made in-depth study by Karl Fischer trace water analyzer. The result shows that the method was simple and accurate. It not only determined the hydrolytic stability of borate ester, but also quantified the extent of its hydrolysis which had important significance in actual production.

Abstract: This study investigated the structures and properties of cationic dyeable poly(ethylene terephthalate) (CDP) and easy cationic dyeable poly(ethylene terephthalate) (ECDP) by FTIR, X-ray diffraction, mechanical test, and DSC. The results showed that the FTIR spectrums of CDP and ester-type ECDP fibers were similar to the that of PET. It suggested that the adding of the third monomer and the fourth monomer had good compatible with the original structure unit of PET. the position of X-ray diffraction peak of CDP and ester-type ECDP were the same as which of PET, the third monomer and the fourth monomer did not pack into the original polyester unit cell but concentrated at the polyester crystalline surface and the amorphous regions.With adding the third monmome and the fourth monmomer, the initial modulus of the CDP and ester-type ECDP fibers became inferior. But the breaking elongation of them increased. The DSC suggested that The melting range of CDP and ECDP finished fiber were wider than that of PET fiber, but the melting point and crystallinity were less than them of PET fiber.

Abstract: Polyamic acids (PAA) were synthesized by solution polycondensation of aromatic diamine with dianhydride and PAA were readily soluble in polar organic solvents (N-methylpyrrolidinone, N, N-dimethylacetamide and DMF). It was found that the most appropriated reaction conditions of synthesis of PAA solution were the ratio of dianhydride with diamine being 1.02:1and 3h reaction time at ambient temperature in both N-methylpyrrolidinone and N, N-dimethylacetamide polar organic solvents. PAA thin films were prepared by PAA solution spread on the glass plate and PI thin films were obtained by the casted thin films which underwent a special high-temperature (300°C, 2h) heat curing. The structures of PAA and PI films were characterized by FT-IR spectra and degree of imidization of PAA solution was indicated from IR spectra. The thermal stability was studied by thermogravimetric analysis (TGA) and the thermal behaviors were investigated by differential scanning calorimetry (DSC) in this paper. It was shown that PAA solution were imidization at 200°C mostly and PI had higher thermal stability.

Abstract: A novel PEG200 lauric acid diester was synthesized high yield by direct esterification using polyethylene glycol and lauric acid respectively was presented in this work. The product of PEG200 lauric acid diester was characterized by a fourier transform infrared spectrometer(FTIR). The effects of catalyst, reaction time, reaction temperature and molar ratio on the reaction were discussed. The optimum synthetic condition of PEG200 lauric acid diester: esynthesis is based on protection of N₂ and the ressure is 0.08Mpa. Using mass fraction 0.45% in p-toluene sulphonic acid as catalyst, molar ratio of polyethylene glycol and oleic acid 1:1.95, reaction temperature about 130-140°C, and reaction time 9-10h. The results of testing of diester products showed that the yield of PEG200 lauric acid diester is 98.2%.And this article reviewed the effect of concentration on viscosity. The characteristic curve of Viscosity-Concentration showed the viscosity increased with increase of the concentration which brought about the increase of particle size. Especially focusing on the maximum viscosity appeard on 80% because of the phenomenon of reverse micelles. Then the viscosity decreased with increase of the concentration.

Abstract: we introduced a fast, specific, and sensitive sensing probe to detect Toxoplasma gondii DNA based on mechanism of fluorescence resonance energy transfer (FRET), and a multifunctional and magnetic-fluorescent CdTe/Ni quantum dots (mQDs) was prepared as energy donor, and BHQ2 was used as energy acceptor, respectively. CdTe/Ni mQDs were synthesized with a more simple method using Ni nanoparticles as core material and CdTe as shell material. The sensing probe was fabricated through labeling a stem-loop Toxoplasma gondii DNA oligonucleotide with CdTe/Ni mQDs at the 5′ end and BHQ2 at 3′ end, respectively, and the resulting sensing probe can be conveniently isolated and purified with a common magnet. Properties of mQDs and sensing probe were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), and fluorescence spectrum (FS) methods. The TEM data demonstrated that the size of Ni nanoparticles was estimated to be ~10nm, and size of CdTe/Ni is 15nm. XRD data showed similar spectrum of CdTe and CdTe/Ni, intensity of Ni (111) typical diffraction peak was detected, which inferred the formation of CdTe on surface of Ni core. An obvious fluorescence recovery (FR) was observed when the complete complimentary target Toxoplasma gondii DNA was introduced comparing with the target DNA with one-basepair-mismatch, this result revealed the sensing probe has high sensitivity and specificity. The current sensing probe will has great potential applications in the life science and gene diagnostics.