Polyisobutylene (PIB) does not have one fixed molar mass because it is a polymer with different chain lengths. Tianjin Gnee Biotech Co., Ltd. supplies Polyisobutylene (PIB) in different molecular weight grades and provides product specifications for buyer evaluation. PIB is also known as polyisobutene and has CAS No. 9003-27-4.
What Is the Molar Mass of PIB?
The repeating unit of Polyisobutylene has a molar mass of about 56.11 g/mol. Its repeating-unit formula is (C₄H₈)ₙ, with the simplified structure:
–[CH₂–C(CH₃)₂]ₙ–
The actual molar mass of PIB depends on the number of repeating units (n). Therefore, 56.11 g/mol refers to one C₄H₈ repeating unit, not the complete PIB polymer.
Why Do PIB Grades Have Different Molecular Weights?
Different PIB grades have different molecular weights because they contain polymer chains of different lengths. Lower-molecular-weight PIB generally offers easier flow and blending, while higher-molecular-weight PIB provides greater viscosity and cohesive properties.
PIB grades are commonly described using Mn (number-average molecular weight), Mw (weight-average molecular weight), or Mv (viscosity-average molecular weight). The suitable grade depends on the requirements of the final application, such as lubricant additives, adhesives, sealants, and rubber modification.
Ready to discuss your requirements? [Get a Quote for Polyisobutylene (PIB)] and tell us your required grade, quantity, and delivery destination.
What Should Buyers Know When Purchasing PIB?
Buyers should specify the required molecular weight or PIB grade when requesting a quotation. CAS No. 9003-27-4 alone does not identify a specific molecular-weight grade.
For Polyisobutylene (PIB) CAS 9003-27-4, buyers can provide the required molecular weight, quantity, packaging, and application when contacting Tianjin Gnee Biotech Co., Ltd.
| PIB Grade | Approximate Molecular Weight | Typical Form | Common Uses |
|---|---|---|---|
| Low MW PIB | 300–3,000 g/mol | Viscous liquid | Fuel and lubricant additives, tackifiers |
| Medium MW PIB | 40,000–150,000 g/mol | Semi-solid to solid | Sealants, rubber compounding |
| High MW PIB | 300,000–1,000,000+ g/mol | Solid elastomer | Butyl rubber, specialty elastomers |
Need a specific molecular weight grade for your application? Check our [Polyisobutylene (PIB) Product Details] for specifications and available grades.
FAQ
How Do I Choose the Right PIB Molecular Weight Grade?
The right PIB grade depends on the application, required viscosity, and processing requirements. Low molecular weight PIB is generally easier to blend, while higher molecular weight grades provide greater viscosity and cohesive properties.
What PIB Molecular Weight Should I Specify in an RFQ?
Buyers should specify the target molecular weight or molecular weight range when requesting PIB. If available, providing Mn, Mw, or Mv requirements helps suppliers identify the appropriate grade more accurately.
Does Higher Molecular Weight PIB Mean Higher Viscosity?
Higher molecular weight generally results in higher viscosity, although the actual value also depends on temperature, concentration, and product grade. Buyers should therefore compare viscosity data under the same test conditions.
Can Different PIB Grades Be Used for the Same Application?
Different PIB grades may be suitable for the same application but can provide different processing and performance characteristics. Buyers should evaluate molecular weight, viscosity, and formulation requirements before selecting a grade.
Need to evaluate the product before placing an order? [Request a PIB Sample] for your application testing.