Chun Peng Wang

Preparation and Characterization of Lignin-Phenolic Foam

In this paper, lignin could partly replaced phenol to prepare lignin-phenolic(LPF) foam.The effects of amount of lignin on mechanical properties, thermal stability, fire-retardant and micro-structure of LPF foam. The results indicated that the addition of lignin decreased the brittleness and flexibility of foam, and the foam hole became larger in diameter and distributed more unevenly. When the lignin replacement amount was lower, the foam had regular foam hole structure and even distribution of foam hole, the size of foam hole increased with an increase of lignin content, SEM observations were in accordance with the early research of the mechanical properties of foams. And the addition of lignin slightly affected the fire-retardant and thermal stability of foam. When lignin replacement amount was 30% and 40%, the critical oxygen index of foam was even slightly higher than the pure PF foam.

Chemical Modification of Soy Flour Protein and Its Properties

This work is to examine ways to chemically modify soy proteins flours and analyze the results and determine the adhesive performance. Reaction with acetic anhydride converts amine and hydroxyl groups to amides and esters, respectively that are less polar and can make the adhesive more water resistant.The succinic anhydride reacts with these same groups but the products have terminal carboxylic acid groups that can react with the polyamidoamine-epichlorohydrin (PAE) resin that is used to cross-link the soy adhesives for improving bond strength. The attenuated total reflectance infrared spectroscopy (ATR-IR) is used to examine changes in the soy flour in going from unmodified to acetylated and succinylated state.

Preparation and Performance Research on Phenolic Insulation Foam Used Low-Temperature Foaming Technology

The phenolic(PF) foams were prepared used low-temperature foaming and curing method. The optimum low-temperature foaming processing technology conditions and material proportioning were described below. The curing temperature was 40 °C, the amount of foaming agent iso-pentane was 8-10wt.%, tween-80 dosage was 6-7wt.%, the amount of composite curing agent was 15-18wt.%.The effects of low-temperature foaming on mechanical properties, heat insulation, fire-retardant, foam hole form and micro-structure were discussed. 40°C and 70°C curing PF foam performance comparison results showed that low-temperature curing technology slightly affect the fire-retardant properties of PF foam. And excellent overall performance PF foam were prepared with 40°C foaming technology, the foam hole morphology structure, toughness and strength of PF foam were better. In addition, the low-temperature curing PF foam had more even foam hole distribution, more regular foam hole structure, more clean foam hole arrangement.

Preparation and Characterization of Phenolic Foam Modified by Nitrile Butadiene Rubber Powder

Abstract: Phenolic-Formaldehyde(PF) foam was improved by co-foaming of PF resin modified using Nitrile Butadiene Rubber Power(NBRP) and other additives in the closing mould at 70°C. The effects of amount of NBRP on mechanical properties and microscopic structure of NBRP-PF foam were investigated. The results indicated that NBRP can improve the mechanical properties.When 2 percent NBRP of foam was used, the comprehensive performance was the best. This could be a consequence of cooperation of NBRP and PF resin.

The Physical and Chemical Analysis of Carbohydrate Content in Acorn Kernel

Carbohydrates are the main source which required to maintain energy equilibrium and normal life activities. In acorn kernel, soluble polysaccharides and starch are the main carbohydrate. In order to accurately measure the carbohydrate content of the acorn kernel in Nanjing Area. Dual-wavelength spectrophotometry and anthrone-sulfuric methods were applied to measure the content of amylose, amylopeetin and soluble polysaccharides,respectively.The other two samples were simultaneously measured for comparative analysis.Testing results show that acorn kernel contain about 79.40% of starch, amylopectin content was up to 59.01%, polysaccharide content is 6.53%.The results indicate that acorn kernel was an important raw material for preparing food, feed and starch-based composites.

A fluorometric and colorimetric dual-mode sensor based on nitrogen and iron co-doped graphene quantum dots for detection of ferric ions in biological fluids and cellular imaging

N, Fe co-doped graphene quantum dots (N, Fe-GQDs) with excellent fluorescence performance were prepared by a simple one-pot hydrothermal method. During this process a dual doping strategy with chelated metal ions in combination with nitrogen passivation was developed. With this strategy, introducing Fe and retaining more oxygen-containing groups by chelation, in conjunction with N passivation, led to a dramatic enhancement of photoluminescence for N, Fe-GQDs. Furthermore, a fluorometric and colorimetric dual mode nanosensor based on the N, Fe-GQDs was prepared for effective and selective detecting of Fe3+ ions. More significantly, it was found that the as-prepared N, Fe-GQDs can be applied to detection of Fe3+ ions in biological samples and cellular imaging, which has a huge potential for utilization in practical applications.

Preparation and Property Studies of Core-Shell Structure Polyacrylate Microspheres for Plastisol

Soft-core/hard-shell polyacrylate latex with different cross-linking degree and shell thickness were prepared by semi-continuous seed emulsion copolymerization .The size, size distribution and morphology of latex particles were characterized using dynamic light scattering (DLS) and scanning electron microscopy (SEM). The properties of plastisol were investigated by testing their dynamic viscoelasticity and storage stability as well as the mechanical properties. The results showed that the latex particles always keep regular spherical structure throughout the polymerization process; Dynamic viscoelasticity of plasticized system with different cross-linking degree however had little changed. The mechanical properties of the plastigels could be improved by increasing the thickness of shell.

Study on Mechanical Property of Polylactic Acid Toughened by Polyacrylate Microsphere

Polyacrylate microsphere with different core/shell ratio (mass ratio) were prepared by semi-continuous seed emulsion copolymerization using butyl acrylate (BA) and methyl methacrylate (MMA) as main monomers，which were used to toughen polylactic acid (PLA) after drying. The effect of core/shell ratio of polyacrylate toughening agent (ACR) on mechanical properties of PLA was studied. The results showed that when adding 8wt%ACR, the impact strength and elongation at break of PLA were both first increased and then decreased as increasing of core/shell ratio, while the tensile strength loss of PLA was little changed. It is found that the impact strength was increased about 24% than that of neat PLA as well as the elongation at break was increased from 2% to 12% when the ratio was 7/3, which was the best ratio.

Effect of Acid Curing Agent on the Foaming of Liquefied Bamboo-Based Resol Resin

In this paper, effect of acid curing agent on the foaming of liquefied bamboo-based resol resin (PBF) were studied. The research result indicated that the optimal acid curing agent were mixture of p-toluenesulfonic acid and H3PO4, curing of PBF resol resin was analysized in detail and computer-aided software was applied for calculating thermodynamics characteristic of foaming process so that integrative assistantwas controlled better. Its apparent activation energy was 1.226 kJ·mol-1. The PBF foam showed satisfactory densities and compressive properties.

Preparation and Properties of Internally Plasticized Bio-Based Film

This paper demonstrated acylation of cellulose with long chain fatty acid and internally plasticized cellulose films obtained by casting. The degrees of substitution (DS) and molar yields of fatty acid, Ts-Cl amounts and reaction time, and as well as the property of final products were studied. Partially derivative celluloses presented glass transition compared to starting cellulose. However, thermal behaviors of the internally plasticized esters with different DS were similar. Dynamic mechanical thermal analysis (DMTA) in tension mode revealed separate relaxations, denoted α and β, corresponding to the glass transition and side-chain melting processes, respectively. According to this, these longer chain esters (LCCEs) showed promise as internally plasticized cellulose films because the supermolecular structure of cellulose was significantly changed with the introduction of longer substituent.