News Details
Chain extender on the properties of new type polyurethane structure
2017-2-25 14:34:07
Chain extender on the properties of new type polyurethane structure influence, for using HDI as chain extender polyurethane elastomer, glass transition value shows that the importance of hard segment in the polyurethane elastomer. In this case, it is caused by the use of different chain extender. The change of Tg is due to the hard and soft chain segment a certain degree of mixing. It is understood. (physical) crosslinked with a soft chain segment has a significant effect on Tg.
For using DHD as chain extender for polyurethane elastomer, value of glass transition (Tg = - 57 ℃) showed that polyurethane elastomer hard chain segment between a small amount of physical crosslinking. Lower Tg temperature said there is a better phase separation.
From the HEG - type PU tga data, it points out that they appear high glass transition temperature (Tg = - 44 ℃) than those who have the same hard segment content of DHD type polyurethane elastomer. To observe the glass transition temperature change could explain the block of hard segment structure under the action of the mobility of chain extender.
Chemical crosslinking fixed the glass transition temperature of hard segment below the DHD type polyurethane elastomer. This is because the chain of liquidity to reduce and the effect of branched chain extension hinder the formation of hydrogen bonds. HEG type polyurethane elastomer, in the region of the hard and soft segments mixed, there is a similar soft chain segment of Tg value is higher than many hard segment structure of Tg values.
More orderly hard chain segment is through a soft chain segment structure of liquidity effect and formed by chemical crosslinking, this led to less orderly structure of soft segment or crystallization. Molding polyurethane elastomer (dynamic mechanics analysis of DNA) provide information on its viscoelastic properties. DHD and HFG type polyurethane elastomer elastic modulus (E ') and loss Angle tangent value (tan and), different hard segment of crosslinking temperature range from 130 ℃ to 230 ℃.
Elastic modulus (E ') at low temperature (45 ℃) - display and tan and a peak of the glass transition temperature of soft chain segment. For DHD type polyurethane elastomer, temperature, and E 'reduce, this means that the hard segment to form a sufficient number of physical crosslinking. For HEG type polyurethane elastomer, elastic modulus curve shows a smooth section, this suggests that there is physical crosslinking, thus increasing the size of the hard segment connections between areas, caused the important structure reinforcement. The steady period of the glycine as crosslinking agent of polyurethane elastomer is more extensive.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
A reagent grade additives
Elastic modulus (E ') after suddenly reduced to 50 ℃ temperature curve, this can be attributed to molten soft chain segment. DHD type of polyurethane elastomer E 'fell sharply after the curve and heated to 220 ℃ of HEG type polyurethane elastomer E' after a sharp drop in the curve of the heated to 250 ℃, indicating that the hard segment of the physical and chemical network was completely destroyed.
The mechanical properties of polyurethane elastomer depends on its hard chain segment interaction force between the molecules. Stress and strain, elastic modulus and elongation at break is an important characterization of polymers, they show you how to change the isocyanate and/or molecular weight of chain extension agent, as well as chain extender changes leading to the properties of polyurethane elastomer.
Using various chain extender but contain a same soft chain segment of stress strain curve of polyurethane elastomer, three different state is visible, pure elastic deformation in under the condition of the low deformation. Second, the study of all polymer has a shape flow area. Finally, in more than 300% of the curve of pressure increases as you can see, this can be attributed to strain the crystallization of the soft chain segment of chain.
With the increase of dosage of DMPA, dispersions overall decrease of particle size, narrow particle size distribution, stability, film tensile strength and shear strength increase, elongation at break decreased. But DMPA content too high will cause water resistance decreased, by phase transition point, the emulsification process need more water, solids is greatly reduced.
When DMPA content is low, the emulsion viscosity changes along with the increase of DMPA content is not obvious, but when the DMPA content is higher, with the increase of content of hydrophilic group, electric double layer thickness increases and water swelling factors dominate, emulsion viscosity increases significantly.
DMBA as a new generation of hydrophilic chain extender, structure and DMPA are similar, but it can shorten the reaction time, lower energy consumption, save energy, the more superior product performance, but the price is far higher than that of DMPA, so less in industrial application.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
For using DHD as chain extender for polyurethane elastomer, value of glass transition (Tg = - 57 ℃) showed that polyurethane elastomer hard chain segment between a small amount of physical crosslinking. Lower Tg temperature said there is a better phase separation.
From the HEG - type PU tga data, it points out that they appear high glass transition temperature (Tg = - 44 ℃) than those who have the same hard segment content of DHD type polyurethane elastomer. To observe the glass transition temperature change could explain the block of hard segment structure under the action of the mobility of chain extender.
Chemical crosslinking fixed the glass transition temperature of hard segment below the DHD type polyurethane elastomer. This is because the chain of liquidity to reduce and the effect of branched chain extension hinder the formation of hydrogen bonds. HEG type polyurethane elastomer, in the region of the hard and soft segments mixed, there is a similar soft chain segment of Tg value is higher than many hard segment structure of Tg values.
More orderly hard chain segment is through a soft chain segment structure of liquidity effect and formed by chemical crosslinking, this led to less orderly structure of soft segment or crystallization. Molding polyurethane elastomer (dynamic mechanics analysis of DNA) provide information on its viscoelastic properties. DHD and HFG type polyurethane elastomer elastic modulus (E ') and loss Angle tangent value (tan and), different hard segment of crosslinking temperature range from 130 ℃ to 230 ℃.
Elastic modulus (E ') at low temperature (45 ℃) - display and tan and a peak of the glass transition temperature of soft chain segment. For DHD type polyurethane elastomer, temperature, and E 'reduce, this means that the hard segment to form a sufficient number of physical crosslinking. For HEG type polyurethane elastomer, elastic modulus curve shows a smooth section, this suggests that there is physical crosslinking, thus increasing the size of the hard segment connections between areas, caused the important structure reinforcement. The steady period of the glycine as crosslinking agent of polyurethane elastomer is more extensive.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine Raw material ：
TDA industrial, Sichuan production
Ethylene (Et) polymer grade, Shanghai production
TEA industrial imports
A reagent grade additives
Elastic modulus (E ') after suddenly reduced to 50 ℃ temperature curve, this can be attributed to molten soft chain segment. DHD type of polyurethane elastomer E 'fell sharply after the curve and heated to 220 ℃ of HEG type polyurethane elastomer E' after a sharp drop in the curve of the heated to 250 ℃, indicating that the hard segment of the physical and chemical network was completely destroyed.
The mechanical properties of polyurethane elastomer depends on its hard chain segment interaction force between the molecules. Stress and strain, elastic modulus and elongation at break is an important characterization of polymers, they show you how to change the isocyanate and/or molecular weight of chain extension agent, as well as chain extender changes leading to the properties of polyurethane elastomer.
Using various chain extender but contain a same soft chain segment of stress strain curve of polyurethane elastomer, three different state is visible, pure elastic deformation in under the condition of the low deformation. Second, the study of all polymer has a shape flow area. Finally, in more than 300% of the curve of pressure increases as you can see, this can be attributed to strain the crystallization of the soft chain segment of chain.
With the increase of dosage of DMPA, dispersions overall decrease of particle size, narrow particle size distribution, stability, film tensile strength and shear strength increase, elongation at break decreased. But DMPA content too high will cause water resistance decreased, by phase transition point, the emulsification process need more water, solids is greatly reduced.
When DMPA content is low, the emulsion viscosity changes along with the increase of DMPA content is not obvious, but when the DMPA content is higher, with the increase of content of hydrophilic group, electric double layer thickness increases and water swelling factors dominate, emulsion viscosity increases significantly.
DMBA as a new generation of hydrophilic chain extender, structure and DMPA are similar, but it can shorten the reaction time, lower energy consumption, save energy, the more superior product performance, but the price is far higher than that of DMPA, so less in industrial application.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
Spanish
French
Italian
Portuguese
Japanese
Korean
Arabic
Russian