ABRON- R 750
PRODUCT TRADE NAME : ABRON R 750
PRODUCT TYPE : POLYIMIDE RESIN (Bis-itaconimide type) Powder Resin
As a result of the efforts of Indian Space Research Organization to develop a processible polyimide, a prepolymer having excellent processability, stability at room temperature and with moderate cure temperatures was developed. Composites made from this prepolymer have yielded components for space and aerospace applications. ABRON-R 750 is being manufactured by A B R ORGANICS LIMITED with the license from Indian Space Research Organization.
ABRON-R 750 is highly amenable for polar & filament winding technology also. The prepregs made from ABRON-R 750 have a long shelf life of 3 to 6 months at room temperature.
GENERAL PROSEDURE FOR MAKING LAMINATES
Silica/Glass/Carbon cloth is impregnated with the resin solution. The solvent is allowed to evaporate (at 55 – 60°C when DMF is used as an solvent). The prepreg should have resin content of 35 – 40% weight.
The tack & drape of the prepreg is controlled by adjusting the residual solvent content.
The prepregs are stacked in mold and heated to 120°C and held for one hour under 60 psi pressure. The mold temperature is raised to 160 – 165 °C as a second step and maintained for another hour. Final cure is done by heating the mold to 200 – 220 °C for 2 hours under pressure. The laminate is released after cooling under pressure to 80 – 100 °C. Post curing is to be done at about 125 °C for 6 hours.
This procedure, however is not same for all shapes and thickness of laminates. The exact cycle has to be determined based on trials.
APPLICATIONS
- Aerospace & space applications as resin matrix for composites ·
- Slot wedges for locomotive traction motors
SPECIFICATIONS OF ABRON – R 750
| State | Fine Powder |
| Colour | Light Pinkish Brown |
| Specific Gravity at 25°C | 1.1 |
| Solubility | NMP / DMF |
| Bulk viscosity of 40% Solution | 40 – 100 cP |
| Shelf life of Resin Powder | 6 months at ambient temperatures (< 400 C ) |
| Service Temperature | -200 to +300°C |
| Cure Temperature | 200 °C – 230 °C |
| Dielectric Constant | 80 – 90 KV/mm |
| Surface Resistivity at 25 °C | 0.5 X 1014 Ohm.cm |
| Volume Resistivity at 25 °C | 2.9 X 1014 Ohm.cm |
| Tan d at 25 °C | 0.004 |
| Volume Resistivity at 200 °C | 4.7 X 1012 Ohm.cm |
| Tan d at 200 °C | 0.025 |
MECHANICAL PROPERTIES OF LAMINATES (ASTMD – 1184)
CARBON FIBRE ( UNIDIRECTIONAL)
| TENSILE STRENGTH | 8 X 103 kg/cm2 |
| FLEXURAL STRENGTH | 5.5 x 103 kg/cm2 |
| INTERLAMINAR SHEAR STRENGTH | 305 kg/cm2 |
GLASS FIBRE ( UNIDIRECTIONAL )
| TENSILE STRENGH | 5.2 X 103 kg/cm3 |
| FLEXURAL STRENGTH | 5.0 X 103 kg/cm3 |
| INTERLAMINAR SHEAR STRENGTH | 135 kg/cm2 |
ELECTRICAL PROPERTIES OF GLASS POLYMIDE COMPOSITE
- Dielectric Constant at 10 KHz frequency with 3.3 mm thick laminate = 2.1
- Descipation factor at 10 KHz frequency with 3.3 mm thick laminate = 0
- a) Electromagnetic radiation transparency with unidirectional glass/ PI laminate at 11.9 G.Hz ——- 89%
- b) Glass cloth – PI laminate ——- 52% c) Glass cloth-epoxy laminate ——- 5 6%
| Tensile strength | 400 Mpa |
| Flexural strength | 450 Mpa |
| Inter Laminar Shear strength | 25 Mpa |
| Resin content | 26 to 28% only |
| Density | 1.8 – 1.9 gm/cc |
The above properties meet the requirements of composites functioning uptoo 220°C and at 400°C for short duration application.
MECHANICAL PROPERTIES OF LAMINATES BASED ON ABRON – R 750
| Composite systems | Tensile strength 103 kg/cm2 Av S.D |
Flexural strength 103 kg/cm2 Av. S.D |
Interlaminar shear
Strength kg/cm2 Av. S.D |
|
ABRON R 750/carbonUnidirectional |
8.094 0.055 |
5.79 0.565 |
305.55 23.22
|
|
ABRON R 750/glassUnidirectional |
– – |
8.614 1.15 |
325.9 6.30
|
|
ABRON R 750/glass Cloth |
– – |
3.62 0.11 |
250.9 5.8 |
MECHANICAL PROPERTIES OF THERMALLY AGED PROPERTIES
|
Temperature0 C
|
Flexural strength |
ILSS |
| ABRON R 750 | ABRON R 750 | |
| 30 | 2530 | 325 |
| 150 | 2741 | – |
| 175 | 2806 | – |
| 200 | 2840 (2261)* | 291.5 |
| 250 | 3022 | 300 |
Value obtained after soaking the sample for 100 hrs at 200°C.