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Liu J.,Dalian Polytechnic University | Feng N.,Dalian Polytechnic University | Chang S.,China Leather and Footwear Industry Research Institute | Kang H.,CAS Institute of Chemistry
Applied Surface Science | Year: 2012

In order to improve the compatibility of magnesium hydroxide particles [Mg(OH) 2] and polymer matrix, poly(glycidyl methacrylate) (PGMA) grafted from magnesium hydroxide particles were synthesized via surface-initiated atom transfer radical polymerization (SI-ATRP). In this work, two approaches for the immobilization of ATRP initiator on the magnesium hydroxide particles surface were compared and selected. The density of initiator was significantly increased by the method of introducing more hydroxyl groups via ATRP of 2-hydroxyethyl methacrylate (HEMA) on the surface. The percentage of bromine atom for the initiator-functionalized magnesium hydroxide particles [Mg(OH) 2-g-PHEMA-Br] reached to 1.75%, compared to 0.48% for Mg(OH) 2-Br determined by XPS analysis. The surface-initiated ATRP of glycidyl methacrylate (GMA) can be conducted in a controlled manner, as revealed by the linear kinetic plot, linear increase of number average molecular weight (M n) with monomer conversions, and the relatively narrow molecular weight distributions (M w/M n ∼ 1.4) of PGMA chains. The percentage of grafting PG (%) and the thickness of the grafted polymer layer increased with the increasing of polymerization time and reached to 116.6% and 197.6 nm after 300 min respectively. As for the polymerization with different initial monomer concentration, the number average molecular weights (M n) and weight average molecular weights (M w) of PGMA increased with the increasing of initial monomer concentration. TGA indicated that the initial decomposition temperature of Mg(OH) 2-g-PHEMA-PGMA composite particles (253°C) was much lower than that of unmodified magnesium hydroxide particles (337°C). © 2012 Elsevier B.V. All rights reserved. Source

Xiaoxing L.,China Leather and Footwear Industry Research Institute
Journal of the Society of Leather Technologies and Chemists | Year: 2015

Some of the basic properties of tannery sludge were examined by using GC-MS, atomic absorption spectrophotometry and other methods. The effect of enzyme pre-treatment for tannery sludge was studied. The results showed that the alkaline protease 2709 and neutral protease As.1398 can effectively promote the soluble chemical oxygen demand of tannery sludge. Alkaline protease 2709 enzymatic pre-treatment can promote anaerobic digestion of tannery sludge. It can increase the rate of decomposition of organic matter by 23.01%, and increase methane gas production by 144.89%. Used together with ultrasound pre-treatment alkaline protease 2709 and can promote anaerobic digestion and increase the rate of decomposition of organic matter by 65.63% and gas production by 425%. Source

Qiang T.,Shaanxi University of Science and Technology | Gao X.,Shaanxi University of Science and Technology | Ren J.,Shaanxi University of Science and Technology | Chen X.,China Leather and Footwear Industry Research Institute | Wang X.,Shaanxi University of Science and Technology
ACS Sustainable Chemistry and Engineering | Year: 2016

This paper discusses the terminal carboxyl groups of the hyperbranched polymer (HPAE-C) complexing Al3+ in aluminum sulfate to synthesis a new chrome-free tanning agent (HPC-Al). The molecular structure of HPC-Al was characterized and analyzed by IR, UV, and XRD. In the tanning process, the results indicate the following: (1) The shrinkage temperature of HPC-Al tanning leather is 79.5°C. (2) The shrinkage temperature is greater than 95°C after chrome retanning and about 87°C after zirconium retanning. (3) It has greatly improved the fullness, softness, and physical-mechanical properties of the leather. Meanwhile, the environmental impact assessment after tanning was evaluated. The results show that biochemical oxygen demand, total dissolved solids, and total suspended solids are reduced. This indicates that the use of HPC-Al as a tanning agent, with chrome-free or chrome-less tanning, can be achieved. © 2015 American Chemical Society. Source

Wang X.,Dalian Polytechnic University | Feng N.,Dalian Polytechnic University | Chang S.,China Leather and Footwear Industry Research Institute | Zhang G.,Dalian Polytechnic University | And 2 more authors.
Journal of Applied Polymer Science | Year: 2012

Intumescent flame retardant thermoplastic polyolefin (TPO) composites were prepared to study the relationships between their structure of charred layer (including of the multicellular intumescent layer and the charry layer) and flame retardant properties. They were characterized using the LOI and UL-94 test, which indicated that the best fire retardant behavior (V-0 rating and LOI reach to 28.1%) was obtained at the formulation of TPO/ammonium dihydrogen phosphate/starch (100/60/20). Thermal gravimetric analysis demonstrated that the presence of ammonium dihydrogen phosphate/starch promoted the esterification and carbonization process in lower temperature range while enhancing the thermal stability of intumescent flame retardant TPO in high-temperature range. Scanning electron microscope and optical microscope were shown that, with combustion time prolonged, the intumescent layers obtained greater number of cells, and the charry layer became more compact while the size of the carbon granules became smaller on the surface. Introduction of starch had an obvious effect on the structure of the intumescent and charry layers. The charry layer of the composites with the content of 20 phr starch was more compact and uniform than that of the composites with 50 phr. The weight ratio of ammonium dihydrogen phosphate to starch in the intumescent flame retardant was fixed as 3: 1 which cooperated with each other well to promote a compact charry layer and to obtain the better flame retardancy performance. Therefore, the better the charred layers produced, and the better flame retardant properties they obtained. © 2011 Wiley Periodicals, Inc. Source

Wang X.,China Leather and Footwear Industry Research Institute | Feng N.,Dalian Polytechnic University | Chang S.,China Leather and Footwear Industry Research Institute
Polymer Composites | Year: 2013

The ternary composites of 1,4-cis polybutadiene rubbers (BR), styrene-butadiene rubber (SBR), and natural rubber (NR) foams containing chemical blowing agents Oxybis (benzene sulfonyl) hydrazide (OBSH) were prepared by two-stage compression molding technique with various precured degrees. Foam force rheometer indicated that the cure rate was match with foaming rate at precured degree of 30%, which the time of the maximum foaming rate was earlier only 14 s than that of the maximum cure rate. SEM presented that the number of cell was denser at precured degree of 30% than those with other precured degrees. The average cell size declined, cell wall thickness became thicker, and cell distribution became narrower just as precured degree was increasing. The results of crosslinking density was measured by equilibrium swelling technique in good agreement with that of magnetism resonance crosslinking density spectrometer measurement, which crosslinking density was increased as precured degrees increased. Differential scanning calorimeter showed that each curve exhibits two steps in heat capacity for BR/SBR/NR foams. With further increase of precured degrees, the two groups of Tgs were all shift to the higher temperature, and the area of the melting peak decreased gradually between -20°C and -40°C. TGA results demonstrated that BR/SBR/NR foams with various precured degrees obtained better thermal stability than those of non-precured foams. The high density of polymeric foams exhibits the high mechanical properties such as tensile strength, tear strength, and elongation at break. The inflection points of density, cell density, and hardness were all appeared at precured degree of 30%. © 2013 Society of Plastics Engineers. Source

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