News Details
Chain extender agent on the properties of WPU emulsion
2017-2-27 12:18:30
Chain extender agent on the properties of WPU emulsion, average size and its distribution. This work by Ng210 macromolecular hydrophobic chain segment composition of soft segment, IPDI and small molecule chain extender hard period of synthesis of WPU emulsion, using two step will hydrophilic chain extender according to certain quality than the introduction of hard segment region, makes the WPU with similar effect of polymeric surfactants, can pass the emulsifying dispersion in water to form stable emulsion.
In the molar ratio of NCO and OH groups of 2, DHPA dosage on the properties of the emulsion were studied. The study found that with the increase of dosage of DHPA, particle size of emulsion is reduced, the narrow particle size distribution, this is because the DHPA continuously introducing the WPU the hydrophilicity of polymer chain segment has been increasing.
, compared to the carboxylic acid type WPU emulsion preparation by this work smaller mean particle size less than 100 nm (dn), particle size distribution is more even less than 012 (PDI), because the acid salt - SO3Na hydrophilic than weak acid salt - COO (NCH2CH3). 3. PDI were greater than 011 emulsion, emulsion is more dispersed system, the carboxylic acid type WPU emulsion are similar, but the latex solid content up to 61%.
The viscosity and rheology. Increase significantly with the increase of DHPA dosage, emulsion viscosity, this is because is the most main factors that affect the viscosity of the emulsion system of emulsion particle size and size distribution. In polymer composition and under the constant ionic strength, the smaller the particle size of latex particle, its surface area is larger, the stronger the interaction between particles, leading to the system viscosity, especially for the larger amount of hydrophilic group increased faster.
This is because the amount of hydrophilic group, the greater the number of particles, the smaller the particle size, the smaller the average distance between particles. Reduce means that the distance between any two particles into attract each other the opportunity to increase rapidly, displacement is difficult, lead to the emulsion viscosity. In addition, with the increase of the amount of hydrophilic group, the result of the hydrophilic enhancement of water swelling sex make effective particle size increases, as a result, the particle moving resistance increases, the emulsion viscosity increase.
Increase with the shear rate, apparent viscosity of the emulsion fell sharply at the beginning, then become slow and steady, namely the high solid content of WPU emulsion exist "shear thinned" behavior, show that the emulsion has the characteristics of pseudoplastic fluid.
The micro morphology. WPU emulsion basic spherical colloidal particle, no obvious rod structure, which with high solid content reported in literatures WPU emulsion significant differences in the colloidal particle shape.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Uses:
The product is identical to Ethancure 100 and Lonza DETDA 80, DETDA is very effective polyurethane elastomer chain extender; also be used as polyurethane and epoxy resin curing agent, epoxy resin of an antioxidant, industrial oils and lubricants . In addition, also as intermediates in organic synthesis.Especially for the RIM (reaction injection molding), is important in the field of spray polyurea chain extender species. Also can be used for casting polyurethane elastomer (CPU) and a curing agent, epoxy curing agent, epoxy resin of antioxidants, lubricants and industrial oils other antioxidants.
The latex particle size is bigger and is very uneven, gap between particles is very large, basic no obvious adhesion between particles and phenomenon. The latex particle size decreased significantly, and the particle is dense, per unit volume of the particle number increased significantly, the solid content in the former of obviously is increased.
Stability. When the DHPA mass fraction is less than 4%, emulsion appeared 3 times of freeze-thaw gel; When DHPA mass fraction is more than 5%, emulsion by 4 times freeze-thaw gel, suggesting that the emulsion has certain frost resistance, but not as good as nonionic lotion frost resistance is good, the reason for this is that the ionic emulsion stability is derived from the "electric double layer structure of latex particles, so the frost resistance is a bit poor.
Emulsion showed good stability at high temperature, it is because the DHPA provides latex particles with sulfonic acid ions, these highly hydrophilic groups provide charge for latex particle, to enhance the "electric double layer structure" of potential, between latex particles formed strong electrostatic repulsion, prevent the latex particle agglomeration.
Hydrophilic groups will be a layer of water adsorption in the surface of latex particle, hydrate formation, increase the space of latex particle size, prevent the latex particles due to close to the chance of condensation. So while latex solid content as high as 60%, its still very stable. The storage stability of the emulsion is very good also, placed more than 6 months at room temperature does not appear obvious stratification.
The mechanical properties of polyurethane (pu) not only associated with the structure of hard segment, but also depends on the number of hydrogen bonds formed between hard segment and hard segment. Change the mechanical properties of polyurethane chain extender agent income has a significant difference.
Because, with the increase of dosage of chain extender polyurethane hard segment structure exists in the ammonia ester, urea, ester, ether groups such as the number and distribution of hydrogen bond has changed.
The crosslinking effect of hydrogen bond formation, thus greatly improve the mechanical properties of materials. In addition, the membrane of elongation at break increased as the hard segment of polyurethane also gradually decline.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
In the molar ratio of NCO and OH groups of 2, DHPA dosage on the properties of the emulsion were studied. The study found that with the increase of dosage of DHPA, particle size of emulsion is reduced, the narrow particle size distribution, this is because the DHPA continuously introducing the WPU the hydrophilicity of polymer chain segment has been increasing.
, compared to the carboxylic acid type WPU emulsion preparation by this work smaller mean particle size less than 100 nm (dn), particle size distribution is more even less than 012 (PDI), because the acid salt - SO3Na hydrophilic than weak acid salt - COO (NCH2CH3). 3. PDI were greater than 011 emulsion, emulsion is more dispersed system, the carboxylic acid type WPU emulsion are similar, but the latex solid content up to 61%.
The viscosity and rheology. Increase significantly with the increase of DHPA dosage, emulsion viscosity, this is because is the most main factors that affect the viscosity of the emulsion system of emulsion particle size and size distribution. In polymer composition and under the constant ionic strength, the smaller the particle size of latex particle, its surface area is larger, the stronger the interaction between particles, leading to the system viscosity, especially for the larger amount of hydrophilic group increased faster.
This is because the amount of hydrophilic group, the greater the number of particles, the smaller the particle size, the smaller the average distance between particles. Reduce means that the distance between any two particles into attract each other the opportunity to increase rapidly, displacement is difficult, lead to the emulsion viscosity. In addition, with the increase of the amount of hydrophilic group, the result of the hydrophilic enhancement of water swelling sex make effective particle size increases, as a result, the particle moving resistance increases, the emulsion viscosity increase.
Increase with the shear rate, apparent viscosity of the emulsion fell sharply at the beginning, then become slow and steady, namely the high solid content of WPU emulsion exist "shear thinned" behavior, show that the emulsion has the characteristics of pseudoplastic fluid.
The micro morphology. WPU emulsion basic spherical colloidal particle, no obvious rod structure, which with high solid content reported in literatures WPU emulsion significant differences in the colloidal particle shape.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Uses:
The product is identical to Ethancure 100 and Lonza DETDA 80, DETDA is very effective polyurethane elastomer chain extender; also be used as polyurethane and epoxy resin curing agent, epoxy resin of an antioxidant, industrial oils and lubricants . In addition, also as intermediates in organic synthesis.Especially for the RIM (reaction injection molding), is important in the field of spray polyurea chain extender species. Also can be used for casting polyurethane elastomer (CPU) and a curing agent, epoxy curing agent, epoxy resin of antioxidants, lubricants and industrial oils other antioxidants.
The latex particle size is bigger and is very uneven, gap between particles is very large, basic no obvious adhesion between particles and phenomenon. The latex particle size decreased significantly, and the particle is dense, per unit volume of the particle number increased significantly, the solid content in the former of obviously is increased.
Stability. When the DHPA mass fraction is less than 4%, emulsion appeared 3 times of freeze-thaw gel; When DHPA mass fraction is more than 5%, emulsion by 4 times freeze-thaw gel, suggesting that the emulsion has certain frost resistance, but not as good as nonionic lotion frost resistance is good, the reason for this is that the ionic emulsion stability is derived from the "electric double layer structure of latex particles, so the frost resistance is a bit poor.
Emulsion showed good stability at high temperature, it is because the DHPA provides latex particles with sulfonic acid ions, these highly hydrophilic groups provide charge for latex particle, to enhance the "electric double layer structure" of potential, between latex particles formed strong electrostatic repulsion, prevent the latex particle agglomeration.
Hydrophilic groups will be a layer of water adsorption in the surface of latex particle, hydrate formation, increase the space of latex particle size, prevent the latex particles due to close to the chance of condensation. So while latex solid content as high as 60%, its still very stable. The storage stability of the emulsion is very good also, placed more than 6 months at room temperature does not appear obvious stratification.
The mechanical properties of polyurethane (pu) not only associated with the structure of hard segment, but also depends on the number of hydrogen bonds formed between hard segment and hard segment. Change the mechanical properties of polyurethane chain extender agent income has a significant difference.
Because, with the increase of dosage of chain extender polyurethane hard segment structure exists in the ammonia ester, urea, ester, ether groups such as the number and distribution of hydrogen bond has changed.
The crosslinking effect of hydrogen bond formation, thus greatly improve the mechanical properties of materials. In addition, the membrane of elongation at break increased as the hard segment of polyurethane also gradually decline.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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