Hao Ran Zhou

One-step synthesis of PI@Fe3O4 composite microspheres and practical applications in Cu(II) ion adsorption

Polyimide(PI)@magnetite(Fe3O4) composite microspheres have been successfully synthesized from poly(amic acid) triethylamine salts (PAAS) and Fe(III) ions by a facile one-step solvothermal process. Furthermore, the formation mechanism of the PI@Fe3O4 composite microspheres has been investigated. The morphology and structure of the samples were both characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and infrared spectroscopy (IR). The results obtained show that the surface of magnetite could be successfully coated with polyimide and the coating could permeate throughout the crystals via a self-assembly process. The size of the composite microspheres was found to increase upon increasing the concentration of PAAS. The thermal properties of the composite microspheres were studied via thermogravimetric analysis (TGA) and the magnetic properties were determined by a vibrating sample magnetometer (VSM). Even though the saturation magnetization of the PI@Fe3O4 composite microspheres is lower than that of pure Fe3O4, the microspheres coated with PI exhibit an increased stability. In addition, basic hydrolysis of the composite microspheres has been carried out and the Cu(II)-adsorption properties of the composite microspheres before and after hydrolysis have been investigated. In doing so, it could be determined that the adsorption capacity of hydrolyzed composite microspheres increases from 5.84 mg g−1 to 24.63 mg g−1.

Research on Performance of Flame-Retardant Epoxy Resin Electronic Packaging Materials

In this article, a new flame-retardant epoxy electronic packaging materials was synthesized through the reaction of matrix resin (E-51), flame retardant (neopentyl glycol phosphate melamine sale, NPM), toughening agent (nitrile rubber, CTBN), curing agent (4, 4-diamino diphenyl sulfone, DDS) and curing catalyst (dosage of benzoyl peroxide, BPO). The results showed that: when the flame retardant was added in an amount of 5wt%, ultimate index (LOI) value of the EPNPM system was increased 2 than that of the EPAl (OH)3 system. When the NPM was added in an amount of 5wt%, the tensile shear strength of the composite was increased 18.27% than that of pure composite. Consequently, the EPNPM system prepared showed betterflame retardance and the mechanical properties.

The Preparation and Characteristics of Chitosan-Acetaminophen Drug-Loading Micropheres

CS-ACAP drug-loading microsperes are prepared with using CS and ACAP as the main raw materials by emulsification-crosslinking method. Orthogonal experiment was designed to optimize the preparation process of the CS-ACAP drug-loading microspheres. FT-IR and SEM were applied to characterize the structure and morphology of microspheres. The sustained release effect of CS-ACAP microsphere was measured by sustained release measurement. The results showed that the CS-ACAP drug-loading micropheres were successfully prepared by emulsification-crosslinking method. Obtained microspheres as a perforated sphere, the average particle size of the microspheres was 30μm and the microspheres had a uniformly particle size distribution; the drug-loaded microspheres had good sustained release effect.

Preparation and characterization of a copper@polyimide core–shell structure via an in situ induction/imidization route

Based on the combination of an in situ induction and imidization method for improving the interface bonding of an inorganic material and a polymer, copper@polyimide (Cu@PI) core–shell composite particles have been successfully prepared from poly(amic acid) ammonium salts (PAAS) and a Cu complex via a simple solvothermal process. The structures and the morphologies of the samples were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM), respectively. It was found that PAAS formed PI via a thermal imidization and subsequently precipitated in the solvent. Through crystallization induction, it then successfully coated on the surface of the formed Cu particles. Based on thermo gravimetric analyses curves and due to no Cu oxidation reactions taking place in the core coated with high-temperature-resistant PI, the weight increase was determined to be 106.4%, instead of up to 124.0% in samples consisting of pure Cu.

Research on Performance of Epoxy Electronic Packaging Materials

This article the epoxy resin electronic packaging materials was prepared via epoxy resin E-51 as matrix resin, MNA for curing agent, the CTBN as toughening agents, BPO, DMP-30, Al(MM)3, 2E4MZ as curing promoting agents by mechanical blending. The cured condition was 80°C curing 2 h, 90°C curing 2 h, 100°C curing 5 h. The structure of the epoxy resin electronic packaging materials was characterized via FT-IR, the result showed that epoxy resin cured completely. Dynamic mechanical analysis (DMA) is evaluated material thermal stability. The results show that anhydride dosage 7.7 g. The dielectric loss and volume resistivity of epoxy electronic potting were measured via the electrical performance analysis. The results show that epoxy electronic potting having BPO (0.2 g) and DMP-30 (0.1 g) had electrical optimal performance. In the curing process conditions, its performance is meet potting requirements, curing process is feasible.

Preparation and Sustained-Release Testing of Chitosan/Montmorillonite/Acetaminophen Microspheres

Chitosan (CS) is an important slow-release carrier of drugs and fertilizers. The pure chitosan have poor performance, it should be added to a certain amount of crosslinking agents, emulsifiers and porogenic agents to improve the performance of it. The advantage of montmorillonite is no pollution and no toxicity, composite material filled in montmorillonite has an excellent mechanical properties. In this article, CS/MMT/ACAP drug-loading microsperes was prepared with the CS, ACAP and MMT as the main raw materials by emulsification-crosslinking method. Orthogonal experiment was designed to optimize the preparation process of the CS/MMT/ACAP drug-loading microspheres. FT-IR, XRD and SEM were applied to characterize the structure and morphology of microspheres. The sustained release effect of CS/MMT/ACAP microsphere was measured by sustained release measurement. The results show that the CS/MMT/ACAP drug-loading micropheres were successfully prepared by emulsification-crosslinking method. The microspheres assumed a good sphericity and a uniform particle size distribution; the drug-loading microspheres had good sustained release effect.

Preparation of Waterborne Epoxy Resin Emulsion

Waterborne epoxy resin was prepared through introducing hydroxyl and carboxyl groups in the main chain of epoxy resin with the bisphenol epoxy resin, toluene diisocyanate and 2,2-dimethylol propionic acid by self-emulsification. Analyzed the structure of products via Fourier transform infrared spectrometer, then to test the water-soluble and stability. And the best conditions of reaction were determined through studying the influence of material ratio, reaction time and reaction temperature to products. The result shows that the synthesized waterborne epoxy resin has favorable stability and water-dispersion.

Research on NPM Used in Flame Retardant Epoxy Potting

As the epoxy potting compound widely used, their flame retardant properties were concerned day by day.This paper neopentyl glycol phosphate melamine salt (NPM) was synthesised via phosphorus oxychloride as the acid source, neopentyl glycol as carbon source, melamine as gas source. The structure of NPM was characterized via infrared spectroscopic analysis (IR). Then the flame retardant properties of NPM/epoxy resin systerm were researched via the limiting oxygen index (LOI), vertical burning experiment, thermal gravimetric analysis (TGA) . The result shows that When the dosage of NPM is 27%, limiting oxygen index of epoxy resin have a extremum, is 32.4, char yield is 18.7% at 600°C. NPM can play a significant role in the improvement of the flame retardant properties of the epoxy.