SGE has a number of different and unique tubing products (Glass Lined Tubing – GLT™ and PEEK™ coated fused silica tubing – PEEKsil™) which allow the chromatographers to perform the applications which are not possible without these formats.
Keep reading on to learn more about how the choice of the correct tubing can help to enhance your chromatography and biotechnology applications.
SGE has been manufacturing silica capillary for more than 30 years and has been successful in bringing together the technologies which have employed optical fiber and tube re-draw industries and merged them with silica glass structure and surface sciences.
Coated fused silica capillary tubing exhibits a remarkable flexibility, with most of the sizes being capable of being looped to a bend radius of 1 inch without the glass fracturing. The key to gaining this flexibility comes from the coating material which is used as it protects the glass from abrasive damage. The resins SGE uses are semiconductor grade polyimides that possess excellent high temperature and electrical insulating properties. The resins also offer exceptional resistance to scuff which is very important for application where the capillary is frequently handled.
High-Temperature Polyimide Coating
- Low Coefficient of Thermal Expansion (CTE): closely matches glass substrate.
- High modulus of elasticity: low deformation when “stretched”.
- High tensile strength supports “tight coiled” capillary applications.
- Continuous operation +400 °C: polyimide cross-linking ensures adequate thermal protection.
- Solvent resistant: cannot be damaged by laboratory chemicals.
- Moderately high modulus of elongation: good flexibility.
- Resistant to UV breakdown: durable to UV exposure.
- Low surface tension finishes: repels oil and water.
- Good optical properties: high light throughput from UV to IR.
- High modulus of elongation: good flexibility.
- Thermoplastic properties: excellent welding properties.
- Easy window production: either chemical or thermal.
- Zero residues on the glass after window production.
Once the drawing process is completed, the capillary tubing is subjected to stress testing many times above the general handling levels to ensure that it is free from structural defects.
The capillary tubing features are:
- High homogeneity.
- 100% proof tested for strength.
- Excellent resistance to thermal shock.
- Chemical inertness.
- Standard polyimide temperature resistance to +400 °C – equivalent to other high-temperature polyimides.
- The polyimide coating is chemically resistant.
- Acrylic coating UV transparent (>240 nm).
- Low dielectric constant, low dielectric loss.
- Impermeable to all gases (except H2, He).
- Free of thermal hysteresis.
- Low weight loss (below devitrification temperature).
- Optical properties of uncoated – transparent above 180 nm.
- High intrinsic tensile strength.
- Uncoated, temperature resistant to 1000 °C.
- Pressure resistant to 1000 bar.
- Very low thermal expansion.
- The internal surface modification is available.
Fused Silica Stability
Fused silica is very stable chemically and shows really excellent resistance to acids. These properties make it perfect for applications which involve various solvents. Distillation of acid solutions and organic reactions. However, in many of the hydrofluoric and phosphoric acids, alkalis and alkali-metalized compounds, dissolution of silica glass and surface devirtification may occur.
Non-deactivated fused silica
- Used in a wide range of capillary GC, HPLC and Bioanalytical applications.
- Made of high quality fused silica.
- Tubing protected with a high-temperature Polyimide resin.