2012年4月8日星期日

The homopolymer live hydrolysis

Homopolymer site hydrolysis process is divided into two parts, the first non-ionic PAM homopolymerization process to produce non-ionic PAM powder; then use the on-site construction hydrolysis device will produce dry powder dissolved, then add sodium hydroxide hydrolysis get the anionic PAM aqueous solution. Redispersible latex powder

Before adding alkali hydrolysis polymerization process

Before adding alkali hydrolysis process multiple complex low-temperature initiator system, and add a degree of polymerization of functional monomers and to improve the solubility of high molecular weight polymer cosolvent in the polymerization process. Polymerization, the polymerization of the polymer gel by cutting, granulation, drying, screening processing powdered poor child quality anionic polyacrylamide product in the kettle or tank reactor. The process is the production of PAM products, relative molecular mass of 19 million.

Homopolymer hydrolysis process

Are poly Hydrolysis process is the first non-ionic PAM homopolymer into the granulation after sodium hydroxide hydrolysis, and finally by drying powdered PAM products. Redispersible latex powder

The composite catalyst system in the process, ie oxidation of the reductant and the thermal decomposition catalyst compound, oxidation of the reducing agent from the role of polymerization reaction, the reaction is essentially an adiabatic process. Colloid by the end of the polymerization after cutting anyone to hydrolysis, high temperature alkali spray to rubber or directly adding alkali particles, and maintain the hydrolysis temperature at 80 . After the hydrolysis process to produce polymer relative molecular mass of about 20 million, but the molecular weight distribution of a wide, high production costs.

2012年4月7日星期六

The Origin of Neutral polyester sizing agent

Sizing papermaking process, the degree of sizing is an important physical indicators indicate the quality of paper or paperboard, and the sizing process is to use the strong hydrophobic material covering the surface of the paper fibers to form a layer of hydrophobic filmreduces the fiber surface free energy, in order to resist the diffusion of water or other liquids on the fiber surface, wetting or penetration, and with this performance material called sizing agent.

The earliest material as a sizing agent is a natural rosin, since the discovery in 1807, it was used nearly 200 years, is still used, just through a variety of methods were modified, conventional sizing acidic sizing, sizing process must make use of aluminum sulfate as a retention agent, rosin acid with negative charge retention in the fiber, to achieve the purpose of sizing, though later on the rosin was modified, prepared maleic rosin saponification gum, fumaric acid rosin, acrylic rosin sizing effect greatly improved, but still must be carried out under acidic conditions sizing.

Many shortcomings due to the acidic sizing, so attention has turned to neutral sizing, 1956, the successful development of synthetic sizing agent of AKD, invented in 1968, ASA synthetic sizing agent, because of the sizing agent of the class applied for reactive glue, can and fiber reaction, keep their own, and thus do not need the help of aluminum sulfate, sizing in high PH value, neutral or alkaline sizing.








2012年4月6日星期五

Cationic rosin sizing agent Review(一)

Domestic cationic rosin sizing agent there are three kinds of methods: cationic method, the cationic emulsion method and the transformation method.
Cationic law

Itself cationic use the reaction of the carboxyl or small monomer rosin and unsaturated cationic copolymer introduced in the rosin molecule cationic achieve cationic, namely through the rosin itself to the formation of the cation, then add the cationic or non-ionic surfactant agent rosin emulsified and dispersed, some cationic rosin itself is a surface active agent can be directly on the rosin emulsified and dispersed to obtain high dispersion glue. The formation of cation resin such as rosin and unsaturated quaternary ammonium salts by the Diels-Alder reaction. Unsaturated monomer and rosin acid copolymer ene Class C trimethyl ammonium chloride, allyl butyl trimethyl ammonium chloride, dimethyl (dimethylamino) ethyl acrylate and so on. The cationic rosin, synthetic methods:  abietic acid with epichlorohydrin reaction and generate intermediates and then further reacted with amines to the formation of quaternary ammonium salts can also be as rosin Mr. glycidyl, and then amination quarter post-ammonium quaternary ammonium salt; rosin acid is first formed with diethylene triamine  amide, and then dimethyl sulfate quaternized; rosin amine reaction with ethylene oxide generated rosin acid polyoxyethylene ether, quaternary ammonium salt with chlorine methylamines .
Cationic rosin sizing material is generally difficult to emulsify, to select the appropriate emulsifier, emulsifying temperature and time conditions. Studies have shown that certain amount according to the method  the synthesis of their own cationic rosin material, respectively, under mechanical stirring the water with the temperature, mass fraction of 0.1% peregal -15 aqueous solution, 0.1% OP-10 aqueous solution 0.1% TX-10 solution dubbed a certain concentration of latex, rubber latex interface migration rate determined by electrophoresis, the calculation of the zeta potential of 30 mV, more than the product of the U.S. Hercules .

2012年4月4日星期三

Effects of Fatty Acid Components Present in AKD Wax on Emulsion Stability and Paper Sizing Performance

abstract

  Commercial alkyl ketene dimer (AKD) waxes generally contain 80-90% AKD and the rest of the components are by-products, such as fatty acids, acid anhydrides, and AKD oligomers. 
In this paper the effects of fatty acid components present in AKD waxes
 on AKD emulsion stability and paper sizing performance were using AKD 
emulsions prepared from a mixed AKD wax with 0-12% stearic acid and palmitic acid. Repeated thermal-shock treatments revealed that the fatty acids-containing AKD emulsions unstable at 3% fatty acid content was, while those
 with 12% fatty acids were quite stable. When the addition of fatty acids was increased 
up to 12%, increased zeta potentials of the AKD emulsion particles of 1.4 mV to 4.4 mV 
with increasing fatty acids. This increase of the zeta potential can be one of the factors that 
will lead to a decrease in AKD retention ratios in broadsheets. Thus reducing fatty acid
 components in AKD waxes not only the pure AKD content present in the growth, 
but also have negative effects on the emulsion stability and paper sizing performance. 
These results indicate that fatty acids in AKD waxes are regulated sufficiently kept 
as low as possible to a standard level of AKD wax to maintain quality.

2012年3月31日星期六

Flocculation of starch-coated solidified emulsion droplets and calcium carbonate particles


abstract

  In paper manufacture, many colloidal particles are added to improve with a pulp suspension on paper. Under the right conditions, these various colloids flocculate and interact. Examples of colloids papermaking fillers and internal sizing agents, opacity and hydrophobicity to improve the paper, respectively. Internal sizing agents (added in the wet end of a paper machine) together emulsion droplets stabilized by cationic starch and other stabilizers solidified. We studied the interaction of a common internal sizing agent, alkyl ketene dimer (AKD), with calcium carbonate fillers. AKD is a liquid over 50-65 ° C (depending on the alkyl chain length) which can be emulsified above its melting point in the presence of a stabilizer, which include, after cooling in the solid colloidal particles to 1 micron in size. We have investigated the interaction of AKD particles stabilized by cationic starch, with precipitated calcium carbonate (PCC) particles. Pure PCC particles are positively charged, but they are in the process water is negative. Flocculation experiments with positively charged and negatively charged AKD were PCC with a photometric dispersion analyzer. Instead of the expected heteroflocculation between AKD and PCC, we observed homoflocculation PCC and AKD homoflocculation, results confirmed by SEM. The results from the transfer of starch from AKD to PCC explains what to PCC flocculation by starch and AKD destabilization due to depletion of the stabilizer.
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2012年3月30日星期五

Preparation of α-alumina-g-polyacrylamide composite abrasive and chemical mechanical polishing behavior


abstract                          
  α-alumina-g-polyacrylamide (α-Al2O3-g-PAM) composite abrasive filaments prepared by surface graft polymerization. Composition, structure and morphology of the product were determined by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectroscopy and scanning electron microscopy, is in each case. Then, the chemical mechanical polishing performance of the composite abrasive body were studied on glass substrates. Atomic force microscopy images show that the average roughness of the polished glass substrate surface can be reduced from 0.74 nm for pure α-Al2O3 abrasive to 0.45 nm for α-Al2O3-g-PAM abrasive.

2012年3月29日星期四

Synthesis and characterization of organic–inorganic hybrid thin films from poly(acrylic) and monodispersed colloidalsilica

abstract
  Hybrid thin films with nano-sized inorganic domain were synthesized from poly (acrylic) and monodispersed colloidalsilica with adhesion promoter. The 3 - (trimethoxysilyl) propyl methacrylate (MSMA) was treated with colloidalsilica first, is bound and then polymerized with acrylic monomer to form a precursor. Then, the precursor was spin-coated and cured to form the hybrid films. The silica content in the hybrid thin films was varied from 0 to 50 wt%. The experimental results showed that the coverage area of the silica particles from the MSMA decreased with increasing silica content and resulted in the aggregation of silica particles in the hybrid films. In this way the silica in the hybrid films from 20 to 35 nm was varied by varying molar ratios MSMA to silica. The results of scanning electron microscopy, transmission electron microscope, and elemental analysis support the above results. The prepared hybrid films from the crosslinked acrylic polymer moiety showed much better film uniformity, thermal stability and mechanical properties than the poly (methyl methacrylate) (PMMA) hybrid materials. Large needle holes were in the PMMA-silica hybrid films found probably due to the significant difference in the thermal properties between the two groups or the evaporation of solvent. The refractive index increases linearly with increasing proportion of silica in the hybrid films. Excellent optical clarity was obtained in the prepared hybrid films. These results show that the hybrid thin films have potential applications as passive films for optical devices.