Flow Injection Polymer Analysis (FIPA)

Introduction

Flow injection polymer analysis is a fast, automated technique for measuring molecular weight, molecular size and intrinsic viscosity of macromolecules. Depending on the sample, analysis times may be optimized to 6-10 samples per hour. Another bonus of FIPA measurements is minimal solvent and sample usage.

Applications

FIPA is a precise, accurate, and effective way to measure polymer properties for routine quality control or process development. The technique can be applied to a variety of aqueous or organic applications like: polyesters, polyamides, polycarbonates, proteins, polysaccharides etc.

Description

In FIPA the polymer or protein in solution is injected in a FIPA system with RI, light scattering and viscometer detectors. Unlike GPC/SEC, FIPA does not provide a distribution of information. Instead, the column technology in the FIPA experiment is used to separate the polymer or protein of interest from any low molecular weight constituents such as diluents, additives or salts that may be in the sample. The sample is measured as a single batch and the analysis takes only a few minutes.

FIPA uses advanced detector technology to fully characterise the sample. The low angle light scattering detector provides absolute molecular weight; the viscometer detector provides intrinsic viscosity and size; while concentration detector(s) provide concentration and information on composition. The precision on all quantities is typically < 1.0 % RSD, and FIPA run times can be under 5 minutes.

Because of the simplicity, speed, precision and accuracy of the analysis, FIPA is well suited to process development or at-line applications where control of processes requires a fast turnaround time for sequential measurements of the extent of reaction. It is also uniquely suited for high throughput scenarios where the number of samples is simply too great for the analysis times involved in GPC/SEC.

Advantages

FIPA is a simple but powerful technique. It is easily automated because unlike GPC it requires no user intervention and is therefore operator independent. FIPA results are obtained quickly, accurately and precisely - allowing rapid decisions to be made about the product quality or process progress.

Results

Using FIPA, the following results can be obtained:

• Molecular weight
• Hydrodynamic size
• Intrinsic viscosity
• Concentration
• Branching
• Copolymer/Conjugate composition

Table 1: Fully automated FIPA results for a broad polystyrene sample. Analysis repeated every 9 minutes and the data analysed automatically by the OmniSEC software without any user intervention.

Examples

A selection of proven FIPA applications include:

• Polycarbonate
• Polyvinyl acetate
• Polymethyl methacrylate
• Linear and branched polystyrene
• Block copolymers
• Low crystallinity olefin rubber
• Polyimide
• Phenolic resins
• Polyurethane
• High crystallinity olefin rubber
• Xylene solubles of polyolefins
• Polyvinyl alcohol
• Polyacrylamide
  

More information

	Featured presentations and application notes:
	Application Communication: FIPA of block copolymers (SBS and SIS) Poly(styrene-butadiene-styrene) a.k.a. SBS rubber as well as SIS elastomers are characterized quickly by FIPA. Accurate absolute molecular weight measurement and intrinsic viscosities are presented.
	Application Communication: FIPA of polyvinyl alcohol (PVOH) Molecular weight and intrinsic viscosities has been measured for 3 samples of polyvinyl alcohol. The mobile phase was water with 0.1 M sodium nitrate. The results show less than 0.5 % relative standard deviation in four measurements.
	Application Communication: FIPA for xylene soluble fraction of polypropylene and impact copolymer A quick Xylene Soluble (XS) test is described in this Application Note. The FIPA method is used to obtain XS results in minutes as opposed to hours. Lengthy filtering and evaporation is not needed for this FIPA analysis.
	Application Communication: FIPA of polymers in HFIP Results for fast FIPA analysis of PET, PBT and Nylon 6,6 are presented. Excellent repeatability on absolute molecular weight, intrinsic viscosity and hydrodynamic radius is presented. The molecular weight measured is in good agreement with the nominal MW.
	Application Communication: FIPA of EPDM elastomers Measurements of Ethylene Propylene Diene (EPDM), a random amorphous elastomer, is carried in 4 minutes in THF at 60 C. Molecular weights and intrinsic viscosities by FIPA and conventional GPC are in good agreement.
	More application notes and online presentations are available to search for FREE in the Malvern Application Library and Presentations Database (Requires Free registration).