Jian Jun Xie

Properties of the Soy Protein Isolate/PVAc Latex Blend Adhesives

Soybean proteins have shown great potential for use as renewable, environmentally friendly adhesives. In this research, poly(vinyl acetate)(PVAc) latex and some auxiliary agent were used to modify soy protein isolate(SPI). The chemical microstructure of the adhesives was obtained by means of Fourier transform infrared spectrometry (FTIR). The influence factors of the bonding strength and the water resistance of SPI adhesive were studied by different mass ratios of the SPI and PVAc latex, the blending time and the crosslink time. A better synthesis condition is as follow, the mass concentration of SPI is 13%; the mass concentrations of urea, PVAc latex and the crosslinker is 6%, 11.1% and 1.5%, respectively(relative to the total mass of SPI and water), and the crosslink time is 1.5h. The thermal properties are studied and the mechanism is discussed.

Adsorption Properties for Superabsorbent of Inverse Suspension Polymerization Poly(acrylate-Co-Acrylamide)

Superabsorbent polymers are lightly crosslinked, hydrophilic polymer network having many functional groups. The adsorption properties in heavy metal ion solutions using poly(acrylate-co-acrylamide)(PAAM) are investigated. It is found that PAAM has a high uptake to heavy metal ions, and that the adsorption of heavy metal ions is greatly influenced by pH and the initial solution concentrations. The biggest and the smallest amount of adsorption are Cu2+ and Cr3+ in CuCl2 and CrCl3 solution, respectively. It was feasible for selective adsorption of the metal ions in the solution onto PAAM hydrogel by controlling the pH values of the mixing solution for CuCl2, FeCl3, CrCl3. Langmiur equatiom can satisfactorily fit for the adsorption of Cu2+ while not fit for that of Fe3+ and Cr3+.

Research on Rheological Properties of Room-Temperature Curing Epoxy Adhesive

The rheological mechanical properties of two kinds of self-designed epoxy adhesive curing systems were studied in this paper through the dynamic and static thermodynamics instrument named EPLEXOR 500N made by GABO® company in Germany. Short-term creep tests were carried out under three different temperature conditions of 20°C, 30°C and 40°C and the rheological model is developed to describe the materials creep law. In addition, the test results from the two different epoxy adhesive are also compared and analyzed.

Preparation and its Properties of the Urea Modified Soy Protein Isolate Adhesives

Soy proteins have shown great potential for use as renewable and environmentally friendly adhesives. The orthogonal experiments are designed for the urea-modified soy protein isolate(SPI) adhesives and the optimum formula is obtained. The mass concentrations of SPI and urea are 14% and 8%(relative to the total mass of SPI and water), the reaction temperature and time are 35°C and 60 min, respectively. Some basic and adhesion properties and its structure of the modified SPI adhesive for the optimum formula are measured. The viscosity is 43Pa.s, and the dry- and wet-state adhesion strengths of the urea-modified SPI optimum formula are 0.96MPa and 0.78MPa(>0.72MPa), respectively according to GB/T10724-2006, which satisfied with the requirement of the II-type plywood. Its surface hydrophobicity is improved and the thermal properties is slightly improved after 200°C. Recently, some concerns about environmental pollution, resource scarcity, and related health issues have pushed scientists to replace the petrochemicals-based synthetic polymers, which are used extensively in construction, packaging, glue and plywood industries, with the bio-based adhesives. SPI adhesives have shown great potential for use as environmentally friendly adhesives in plywood since 1930s when it’s first be developed. And it has been modified by chemical alkali[1], sodium dodecyl sulfate(SDS)[2,3], and urea[2], guanidine hydrochloride[4], etc. However, most of these modifications can not very well improve the water resistance and the bonding strength separately. Poor water resistance is a fatal weakness which seriously restricts the application in the industry. Many studies[5~8] have shown that the adhesives with some enhanced performances, for example, adhesion strength and water-resistant, can be obtained by unloading SPI molecular chain with the hydrophobic group using urea, SDS, other surfactant and guanidine hydrochloride, etc. And the unloading mechanism of the SPI molecular chain with the hydrophobic group is proclaimed. The optimum concentration of urea is 1mol/L for the water-resistant. The aim of this research was to improve the tacky strength and the water resistance[9] by using urea to modify SPI and evaluate the resulting adhesive’s potential for use in the plywood.

High Temperature Resistance of Epoxy Adhesives under the Room-Temperature Curing

High-temperature resistant epoxy adhesives cured under room-temperature becomes more and more important in many industries such as aerospace and aviation, the locomotive and diesel, etc. In this paper three self-made amine-based mannich-amide was mixed with E-44 epoxy resin under the same technological parameters, and the epoxy adhesives cured by the three amine-based mannich-amides under room-temperature are tested by FTIR, TGA and DMA. Results of TGA show a quicker drop in weight occurrence within 150-250°C for epoxy networks cured by multiamine-based mannich amides than the long-chain alkyl one. Results of FTIR show completely curing of epoxy adhesives cured by mannich amides under room temperature and the height of absorption band 1502cm-1 (C-N) is much lower after 12h under 150°C,200°C atmosphere than 25°C. Results of DMA show that the Tg determined by DMA has an order EP AN2(89.9°C) >EP AN1(89.7°C)>EP AN3(80.8°C). In the rest results of DMA, the EP-AN3 system has the biggest storage modulus (E’) within 100-150°C while the EP-AN3 system has the smallest loss modulus(E”) within 100-150°C. As a whole, the epoxy adhesives cured by AN3 under room-temperature have the best high temperature resistance.

Inorganic Clay/Sodium Lignosulfonate Graft Acrylamide and Maleic Anhydride Adsorbent Composites

Adsorbent composites comprising of inorganic clay/sodium lignosulfonate graft-polymerized with acrylamide and maleic anhydride were synthesized by free radical solution copolymerization. The synthesized copolymers presented high adsorption capacity when the monomer ratio of acrylamide to maleic anhydride was 3:2 and montmrillonite was introduced as inorganic clay. The equilibrium adsorption of Pb2+ on these copolymers was well represented by Langmuir model which indicated that the Pb2+ adsorption was a monolayer chemical adsorption. The calculated adsorption capacity of the copolymers could reach a maximum of 176.70 mg/g for Pb2+ and 24.95 mg/g for Cu2+. In addition, these copolymers could selectively remove Pb2+ from Pb2+/Cu2+ binary solution and the maximum selective coefficient of Pb2+ to Cu2+ was 11.939.

Preparation of Adsorbent Composites Based on Bentonite/Sodium Lignosulfonate-g-AM

Adsorbent composites comprising of bentonite/sodium lignosulfonate graft-polymerized with acrylamide (BLPAM) were synthesized. Results showed that the optimized preparation conditions within the experimental range were as follows: the mass ratio of acrylamide to sodium lignosulfonate was 14, the pH of the reaction medium was 4.0, the mass concentrations of the initiator and cross-linker were 0.45% and 0.30%, respectively. The Pb2+ adsorption capacity of the as-prepared BLPAM was 0.161mmol/g.

Saponification of Adsorbent BLPAMA

The saponification conditions for bentonite/sodium lignosulfonate graft acrylamide and maleic anhydride adsorbent composites (BLPAMA) prepared by solution polymerization were studied in detail. The results had shown that the optimum conditions of saponification were that the concentration of NaOH (CNaOH) = 1.0mol/L, the temperature (T) = 90°C and the saponification time (t) = 1.5h. And the maximum adsorption quantity of saponified BLPAMA to Pb2+ was 1.304mmol/g in the Pb2+/Cu2+ binary metal solution.

Preparation and Properties of the Underwater Curing Epoxy Adhesives

The epoxy adhesive is prepared according to the optimal formula of the orthogonal experiment, and its curing properties, the dynamic mechanic parameters, Fourier transform infrared spectrometer(FTIR) and the thermogravimetric analysis(TGA) are measured. And its shear adhesive strength is about 22.0MPa, its tensile strength is about 12.50MPa and its charpy impact strength is 9.41kJ/m2. The result of TGA and dynamic mechanic analysis(DMA) test have shown that the thermal stability of the epoxy adhesive is good before 335°C and its weight retention ratio is more than 90% and Tg≈50°C. By exploring the experiments, the tensile adhesive strength of the dumbbell sample in the concrete for the underwater curing epoxy adhesives is more than 2.26~2.98MPa. Epoxy resins have many excellent properties of mechanics and adhesion. By suitable modification of the epoxy resins, they have widely been applied for the leakage proofing in the underground and the submarine tunnel; the repairing and reinforcing of the dikes, dams and bridges; the repairing of the mechanical, electrical and chemical equipments[1]. Since1960’s, the underwater curing epoxy adhesives are developed and a great many works are done[2-10], for example, α-cyanoacrylate adhesive, the organosilicone adhesive, the urethane adhesive. But the open literatures abroad are few[11]. Zhang et al[12] investigated systematically the viscosity, reavtivity, mechanic and adhesive properties of the underwater curing epoxy adhesives for different curing agent systems, However, these studies concentrate on the laboratory results on the sheet steel piece, and the experimental testes on the damp and underwater concrete samples have not been seen up to now. This paper tried to explore the experiments on the damp and underwater concrete samples and obtained some good results based on the laboratory development on the sheet steel pieces.

Effect of the Ion Strengths in Different Salt Solutions on the Absorbencies of Poly(acrylic acid-co-acrylamide) Superabsorbent by Inverse Suspension Polymerization

The absorbencies of poly(acrylic acid-co-acrylamide) (PAAM) are measured for the ion strengths of the salt solutions using the self-made PAAM by inverse suspension polymerization. The effects of various salt solutions on the swelling properties were studied systemically, and the relationship between the absorbency (Q) of PAAM and the concentrations of different salt solutions(c) could be expressed as Q=kcn. The absorbencies of PAAM decrease obviously with the ion strengths (less than 0.03mol/kg) and had no great change when the ion strengths were higher than 0.03mol/kg for the same solution systems. The absorbency decreased with an increase in charge of the metal cation. The absorbencies of the PAAM in the sodium solutions with different anion decreased with an increase of the ion strengths. However, the absorbencies increased with the increase in charge of the anionic group and were in order PO43->CO32->Cl-.