News Details
Hydrophilic chain extender
2017-2-22 17:43:33
Hydrophilic chain extender, water-based polyurethane is water soluble, water and water dispersible emulsion type polyurethane. Since the 1960 s industrialization, waterborne polyurethane with its excellent performance and environmentally friendly character development rapidly. In leather finishing, textile coating, glass fiber cluster, coatings and adhesives in the fields of application, has become a research hotspot in recent years.
Waterborne polyurethane material is mainly composed of macromolecular polyol, diisocyanate, hydrophilic chain extender, neutralizer, after the chain extender, etc. Production PU dispersions of general process for: polyol vacuum distillation after dehydration, add more isocyanate, can choose whether to join the catalysts, reaction to the NCO reached the theoretical value under 80 ~ 85 ℃, to join the hydrophilic chain extender, you can choose whether to join other chain extender and acetone solvent, such as thermal reaction to NCO after reaching the theoretical value, cooled to 45 ~ 50 ℃, join the neutralizing agent, stirring 0.5 ~ 1 h, the product high speed dispersed in water at the same time to join the chain extender chain extender, uniform dispersion stability, PU dispersion products.
In the process, the effect of hydrophilic chain extender is in advance of the isocyanate polyurethane polymers for extender chain at the same time, the introduction of hydrophilic groups. According to the type of hydrophilic group, hydrophilic chain extender can be classified as chain extender anionic, cationic chain extender and non ionic chain extender. Now the most commonly used in industry is anionic chain extender (2, 2 - dihydroxy methyl propionic acid (DMPA).
As an important component of waterborne polyurethane synthesis process, varieties and amount of the type hydrophilic chain extender, join mode will directly affect the PU dispersion system and the performance of the coating. This article through the analysis of hydrophilic chain extender DMPA structures and properties, to explain its effect on the properties of the PU dispersion, and contrast DMPA and DMBA two different hydrophilic chain extender of PU dispersion system.
2, 2 - dihydroxy methyl propionic acid, also known as alpha, alpha, double hydroxyl methyl propionate, abbreviations for DMPA is a kind of multi-functional compound, its structure is a typical new amyl structure, is a kind of typical structure of glycol. The new amyl structure gives it a good heat resistance, hydrolysis resistance, and color stability.
As with carboxyl of glycol, DMPA can take part in the polyurethane chain extension reaction, in the extender chain reaction due to the steric hindrance effect and reactivity, carboxyl will be preserved, can be converted to ammonium salt or alkali metal salts and water soluble polyurethane, make give polyurethane since emulsifying performance, stability and DMPA can make good from emulsion type polyurethane.
Chinese name: Diethyl toluene diamine(DETDA)
Physical and chemical properties: light yellow transparent liquid, slightly soluble in water, soluble in alcohols, ethers, ketones and other polar organic solvents, and polyether, polyester polyol compatibility.
Density 1.022
Viscosity (20 ℃) ??mPa·ss290±10
Pour Point ℃-9
Boiling point of310°C
Flash Point°C161.1°C
DMPA because of its components as the hydrophilic group introduced, in the period of macromolecular chain distribution, dosage directly affect the particle size of dispersion, thus affecting the dispersion performance, at the same time as in the large molecules into the system of rigid chain segments, DMPA dosage may also affect the mechanical properties of the coating.
Sample preparation mechanism for conventional pharmaceutical with glue, HTPB/IPDI propellant is studied 60 c mixed 80 min, 50 c casting, 70 c curing 7 d.
Uniaxial tensile mechanical properties test. Using INSTRON4301 testing materials tensile machine, according to the specimen and conditions stipulated in the OJ924-85 test propellant mechanical properties.
Crosslinking density test. The self-made crosslinking density meter, adopts swelling modulus method. Swelling modulus method is by measuring the change sample volume before and after the swelling and swelling after the stress-strain relationship, the network of elastomer chemical crosslinking density.
Transmission electron microscope (TEM). Film of epoxy resin embedding, furnishing, ultrathin sectioning, OsO4 dyeing, again on the tem observation and document imaging.
Looked at the increase of the amount of DMPA how the effects of particle size. During the trial, with the increase of dosage of DMPA, waterborne PUA emulsion by a milky white opaque slowly become translucent, eventually becoming solution suffused with red light. This is because with the increase of DMPA content, the average particle size of emulsion changed: from the point of view of thermodynamics, the emulsion polymer in the total free energy of G is changeless, namely Δ G = gamma Δ A, when the dosage of DMPA increases (i.e., - COOH to increase), the hydrophilic polymer increases, the corollary of polymer and water interfacial tension increase with the decrease of and polymer surface area A, Y, when polymer quality must is characterized by particle size smaller.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Waterborne polyurethane material is mainly composed of macromolecular polyol, diisocyanate, hydrophilic chain extender, neutralizer, after the chain extender, etc. Production PU dispersions of general process for: polyol vacuum distillation after dehydration, add more isocyanate, can choose whether to join the catalysts, reaction to the NCO reached the theoretical value under 80 ~ 85 ℃, to join the hydrophilic chain extender, you can choose whether to join other chain extender and acetone solvent, such as thermal reaction to NCO after reaching the theoretical value, cooled to 45 ~ 50 ℃, join the neutralizing agent, stirring 0.5 ~ 1 h, the product high speed dispersed in water at the same time to join the chain extender chain extender, uniform dispersion stability, PU dispersion products.
In the process, the effect of hydrophilic chain extender is in advance of the isocyanate polyurethane polymers for extender chain at the same time, the introduction of hydrophilic groups. According to the type of hydrophilic group, hydrophilic chain extender can be classified as chain extender anionic, cationic chain extender and non ionic chain extender. Now the most commonly used in industry is anionic chain extender (2, 2 - dihydroxy methyl propionic acid (DMPA).
As an important component of waterborne polyurethane synthesis process, varieties and amount of the type hydrophilic chain extender, join mode will directly affect the PU dispersion system and the performance of the coating. This article through the analysis of hydrophilic chain extender DMPA structures and properties, to explain its effect on the properties of the PU dispersion, and contrast DMPA and DMBA two different hydrophilic chain extender of PU dispersion system.
2, 2 - dihydroxy methyl propionic acid, also known as alpha, alpha, double hydroxyl methyl propionate, abbreviations for DMPA is a kind of multi-functional compound, its structure is a typical new amyl structure, is a kind of typical structure of glycol. The new amyl structure gives it a good heat resistance, hydrolysis resistance, and color stability.
As with carboxyl of glycol, DMPA can take part in the polyurethane chain extension reaction, in the extender chain reaction due to the steric hindrance effect and reactivity, carboxyl will be preserved, can be converted to ammonium salt or alkali metal salts and water soluble polyurethane, make give polyurethane since emulsifying performance, stability and DMPA can make good from emulsion type polyurethane.
Chinese name: Diethyl toluene diamine(DETDA)
Physical and chemical properties: light yellow transparent liquid, slightly soluble in water, soluble in alcohols, ethers, ketones and other polar organic solvents, and polyether, polyester polyol compatibility.
Density 1.022
Viscosity (20 ℃) ??mPa·ss290±10
Pour Point ℃-9
Boiling point of310°C
Flash Point°C161.1°C
DMPA because of its components as the hydrophilic group introduced, in the period of macromolecular chain distribution, dosage directly affect the particle size of dispersion, thus affecting the dispersion performance, at the same time as in the large molecules into the system of rigid chain segments, DMPA dosage may also affect the mechanical properties of the coating.
Sample preparation mechanism for conventional pharmaceutical with glue, HTPB/IPDI propellant is studied 60 c mixed 80 min, 50 c casting, 70 c curing 7 d.
Uniaxial tensile mechanical properties test. Using INSTRON4301 testing materials tensile machine, according to the specimen and conditions stipulated in the OJ924-85 test propellant mechanical properties.
Crosslinking density test. The self-made crosslinking density meter, adopts swelling modulus method. Swelling modulus method is by measuring the change sample volume before and after the swelling and swelling after the stress-strain relationship, the network of elastomer chemical crosslinking density.
Transmission electron microscope (TEM). Film of epoxy resin embedding, furnishing, ultrathin sectioning, OsO4 dyeing, again on the tem observation and document imaging.
Looked at the increase of the amount of DMPA how the effects of particle size. During the trial, with the increase of dosage of DMPA, waterborne PUA emulsion by a milky white opaque slowly become translucent, eventually becoming solution suffused with red light. This is because with the increase of DMPA content, the average particle size of emulsion changed: from the point of view of thermodynamics, the emulsion polymer in the total free energy of G is changeless, namely Δ G = gamma Δ A, when the dosage of DMPA increases (i.e., - COOH to increase), the hydrophilic polymer increases, the corollary of polymer and water interfacial tension increase with the decrease of and polymer surface area A, Y, when polymer quality must is characterized by particle size smaller.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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