News Details
Chain extender for polyurethane elastomer structure performance influence
2017-2-24 23:21:26
Chain extender for polyurethane elastomer structure performance influence, the influence of infrared spectrum is used to study the structure of polyurethane elastomer hard chain segment. Polyurethane elastomer infrared research mainly focused on the vibration of the two main areas: one is N - H stretching vibration (3200-3500 cm - 1), the other one is C = O stretching vibration (1690-1730 cm - 1). Because there is a provide N - H and C = O receptor keys, so the polyurethane elastomer can form a variety of hydrogen bond. The spectrum has been widely applied to the characterization of hydrogen bonding of micro phase separation of polymer and related. It is well known that the N - H key polyurethane, N - H and C = O appears in low frequency probability is less than N - H key of polyurethane.
In the case of a new type of polyurethane elastomer, appeared in 3300 cm - 1 a single N - H bond, most of the N - H key is containing hydrogen bond. In the DHD type polyurethane, N - H absorption peak at 3330 cm - 1, shows how low the tendency of polyurethane elastomer hydrogen bond formation, this is due to a three-dimensional DHD branched chain caused by the thermal resistance effect of (22, 24). Crosslinking polyurethane elastomers according to expand areas of absorption peak at 3300 cm - 1, this shows that the hydrogen bond between the low degree of hard segment and soft segment.
For thermal stability test, thermogravimetric analysis is considered to be the best way. Various chain extender polyurethane elastomer thermogravimetric analysis. PU1 and PU2 and PU3 weight loss is very slow, up to 300 ℃, the second is the increase of the weight loss is in 450-500 ℃. To PU4 PU5, PU6, the increase of the weight loss is at 250 ℃. When the temperature range of 300-500 ℃ found that weightlessness curve DHD - PU similar to each other. The HEG - pu from and other curves are different.
Pu4 pu5, and pu6 thermogravimetric data reveal the different structure of the degradation process of hard segment, join the CO of polyurethane, fastest loss is at 250 ℃. And based on the glycine, loss of the fastest is at 350 ℃. Based on the PU weight loss of CO in low temperature, this is according to the existing plasticizing CO chain effect. In the chemical structure of PU HEG (linear in extension and high amount of hydrogen bond in PU chain) the results of the degradation from 250 to 235 ℃. Its main degradation process can be under the condition of the temperature about 400 ℃ was observed.
Polyurethane elastomer thermogravimetric curve, the largest chain extender for DHD is 380-410 ℃, HEG cases is 330-400 ℃. Increase the maximum temperature of crosslinking polyurethane showed that the diffusion of matrix in lower rate of substrate degradation products.
NH12MDI: nPTMEG - 1000 = 3:1, isocyanate index (R = 1 for synthesis. Comparison of PU - EG, PU - 1, 4 - BG and PU - 1, 6 - PG three elastomer, EG extender chain when the PU elastomer hardness, tensile modulus, tensile strength and peel strength are the biggest, tear strength and PU - 1, 4 - BG, but the elongation at break of the lowest when EG extender chain. This is because as the number of carbon atoms in the molecular chain extension agent, the density of hard segment in elastomer became smaller, the compatibility of hard segment and soft segment phase, phase separation effect, make the mechanical properties of PU elastomer come down.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine packing： net weight 200KG/ galvanized iron drum (a small cabinet pallet loaded 16 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons or 23 tons of ISOTANK).
Will PU - 1, 3 - PG compared with PU - 1, 2 - PG, PU - 1, 4 - BG compared with PU - 1, 3 - BG, found in asymmetric 1, 2 - PG and 1, 3 - BG reaction for mechanical properties of PU than with 1, 3 - PG and 1, 4 - BG reaction to get bad, this is because the former of hard segment have the characteristics of asymmetric structure with side group, weakened side base force between molecules, unfavorable to crystallization, so the degree of phase separation is abate, poor mechanical properties.
PMMA and PU interface photos show that after the separation of the PU film with organic glass plate strip away after joining EG as chain extender agent of glass surface is tear off part of the organic glass, glue sample cohesion damage happened; Use other chain extender after stripping machine glass surface damage is lesser, shows that the PU - EG and PMMA adhesive effect is best.
H12MDI main component is 4, 4 'isomer, also contains 3% ~ 10% of 2, 4' isomer. Because there are many kinds of isomer H12MDI, which greatly increases the difficulty for PU molecular structure.
The influence of chain extender on the optical performance. Different chain extender get eight kinds of PU elastomer optical transparency of relationship with the structure of the chain extender. Light transmittance of the PU elastomer were reached more than 90%, the fog degree is less than 1.5%, and chain extender structure on the PU elastomer optical transparency effect is very small. In addition, ultraviolet-visible spectrophotometer to measure the PU - EG, PU - 1, 4 - BDO and PU - 1, 6 - HG light transmittance, you can see that in the visible band, their light transmittance were above 90%.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
In the case of a new type of polyurethane elastomer, appeared in 3300 cm - 1 a single N - H bond, most of the N - H key is containing hydrogen bond. In the DHD type polyurethane, N - H absorption peak at 3330 cm - 1, shows how low the tendency of polyurethane elastomer hydrogen bond formation, this is due to a three-dimensional DHD branched chain caused by the thermal resistance effect of (22, 24). Crosslinking polyurethane elastomers according to expand areas of absorption peak at 3300 cm - 1, this shows that the hydrogen bond between the low degree of hard segment and soft segment.
For thermal stability test, thermogravimetric analysis is considered to be the best way. Various chain extender polyurethane elastomer thermogravimetric analysis. PU1 and PU2 and PU3 weight loss is very slow, up to 300 ℃, the second is the increase of the weight loss is in 450-500 ℃. To PU4 PU5, PU6, the increase of the weight loss is at 250 ℃. When the temperature range of 300-500 ℃ found that weightlessness curve DHD - PU similar to each other. The HEG - pu from and other curves are different.
Pu4 pu5, and pu6 thermogravimetric data reveal the different structure of the degradation process of hard segment, join the CO of polyurethane, fastest loss is at 250 ℃. And based on the glycine, loss of the fastest is at 350 ℃. Based on the PU weight loss of CO in low temperature, this is according to the existing plasticizing CO chain effect. In the chemical structure of PU HEG (linear in extension and high amount of hydrogen bond in PU chain) the results of the degradation from 250 to 235 ℃. Its main degradation process can be under the condition of the temperature about 400 ℃ was observed.
Polyurethane elastomer thermogravimetric curve, the largest chain extender for DHD is 380-410 ℃, HEG cases is 330-400 ℃. Increase the maximum temperature of crosslinking polyurethane showed that the diffusion of matrix in lower rate of substrate degradation products.
NH12MDI: nPTMEG - 1000 = 3:1, isocyanate index (R = 1 for synthesis. Comparison of PU - EG, PU - 1, 4 - BG and PU - 1, 6 - PG three elastomer, EG extender chain when the PU elastomer hardness, tensile modulus, tensile strength and peel strength are the biggest, tear strength and PU - 1, 4 - BG, but the elongation at break of the lowest when EG extender chain. This is because as the number of carbon atoms in the molecular chain extension agent, the density of hard segment in elastomer became smaller, the compatibility of hard segment and soft segment phase, phase separation effect, make the mechanical properties of PU elastomer come down.
Chinese name: Diethyl toluene diamine(DETDA)
Diethyltoluenediamine packing： net weight 200KG/ galvanized iron drum (a small cabinet pallet loaded 16 tons), 1000KG/IB barrels (a small cabinet loaded 18 tons or 23 tons of ISOTANK).
Will PU - 1, 3 - PG compared with PU - 1, 2 - PG, PU - 1, 4 - BG compared with PU - 1, 3 - BG, found in asymmetric 1, 2 - PG and 1, 3 - BG reaction for mechanical properties of PU than with 1, 3 - PG and 1, 4 - BG reaction to get bad, this is because the former of hard segment have the characteristics of asymmetric structure with side group, weakened side base force between molecules, unfavorable to crystallization, so the degree of phase separation is abate, poor mechanical properties.
PMMA and PU interface photos show that after the separation of the PU film with organic glass plate strip away after joining EG as chain extender agent of glass surface is tear off part of the organic glass, glue sample cohesion damage happened; Use other chain extender after stripping machine glass surface damage is lesser, shows that the PU - EG and PMMA adhesive effect is best.
H12MDI main component is 4, 4 'isomer, also contains 3% ~ 10% of 2, 4' isomer. Because there are many kinds of isomer H12MDI, which greatly increases the difficulty for PU molecular structure.
The influence of chain extender on the optical performance. Different chain extender get eight kinds of PU elastomer optical transparency of relationship with the structure of the chain extender. Light transmittance of the PU elastomer were reached more than 90%, the fog degree is less than 1.5%, and chain extender structure on the PU elastomer optical transparency effect is very small. In addition, ultraviolet-visible spectrophotometer to measure the PU - EG, PU - 1, 4 - BDO and PU - 1, 6 - HG light transmittance, you can see that in the visible band, their light transmittance were above 90%.
Copyright: Zhang Jia Gang YaRui Chemical co.,Ltd
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