Solutions for polymer characterization with Advanced Polymer Chromatography(APC)
Polymeric substances are mixtures of molecules with a distribution of molecular weights, and in polymeric materials, this mixture has been developed and used with this distribution present. For this reason characterization of molecular weight distribution is an essential solution to improve material quality standards and speed up product innovation. By adopting state-of-the-art size exclusion chromatography (SEC), we not only shorten analyzing and processing time but also improve quality by more detailed characterization analysis, and lead the business to success.
There is generally no technique for separating and purifying a synthetic polymer into individual chain lengths, there will always be a distribution present. On the other hand, it is also known that the difference of molecular weight and degree of irregularity (molecular weight distribution) greatly influence the fundamental properties of polymers, and furthermore the properties as materials. For this reason, polymers used as materials have responded to market needs by improving and controlling this molecular weight distribution. Today the use of polymeric materials is increasingly diversified. Molecular design of materials including control of molecular weight is indispensable in order to obtain higher performance and higher functional materials which are suitable for individual purposes.
Size exclusion chromatography (SEC), also known as gel permeation chromatography (GPC) is a technique widely used for molecular weight distribution measurement. Measurable parameters include number-average molecular weight, weight-average molecular weight, Z-average molecular weight, and critically molecular weight distribution, which is a fundamental property of polymers. In addition, high resolution GPC can also separate complicated polymer compounds into components such as polymers, oligomers, monomers and additives. Assuming the types and ratios of the additives added to the polymer material are exactly the same, if the molecular weight distribution differs even only slightly between the lots, and if the high molecular weight polymer is excessively mixed during processing, the following features in the end use might be significantly different. Hence, polymer characterization is particularly important when strict performance criteria are required for end use or when tolerances are required under harsh conditions in use.
Example of molecular weight distribution between on- and off-specification products
There are two materials made of the same polymer resin, which have exactly the same tensile strength and melt viscosity, but the performance varies greatly when processing to durable products. This is because there is a slight difference in molecular weight distribution between the two materials and it appears as a serious difference in product performance. This is because there is a slight difference in molecular weight distribution between the two materials and it appears as a serious difference in product performance. The ability to separate and detect small differences on GPC not only reduces products with serious defects, improves yield, but also greatly boost up the development of higher added value products.
Advanced Polymer Chromatography ACQUITY APC
ACQUITY Advanced Polymer Chromatography (ACQUITY APC) technology is a high-speed, high-resolution, size-based separation technology using a low dispersion ACQUITY system and detector, a rigid and high pore volume hybrid particle column. As shown in the figure, APC has much better resolution performance and improvement of analysis time compared with conventional GPC.
The key technology that brings about this result is as follows.
- By using Bridged Ethylene Hybrid (BEH)-based material as a stationary phase of column, it can achieve small particle (less than 3um diameter) with high pressure tolerance.
- Improving bed stability
- The optimized pore volumes and particle sizes provide unmatched separation speed, resolution and chromatographic efficiency.
- Low dispersion system introducing ACQUITY UPLC technology into GPC
- High pressure tolerance and stable pumping system.
- Detector adopting low volume cell that does not compromise separation of peaks
The advantages of APC technology brings to polymer characterization are…
- Sharp peak with high resolution by low dispersion system and high performance column with smaller particle size.
- High speed analysis without compromising high chromatographic resolution.
- One system with several types of solvent analysis.
Rapid solvent switching due to low system volume and elimination of the shrinking and swelling that often occurs with polymeric stationary phase.
- Better chromatographic repeatability by stable and precise flow and low system volume.
Any minor flow fluctuation will result in a potentially large error in molecular weight. It is to your advantage to use the most precise fluid-handling device you can.
ACQUITY APC column
In the development of polymer materials we deal with various types of base polymers, end groups, molecular weight regions and molecular weight distributions. ACQUITY APC XT column allows you to select columns with appropriate configurations for your application. For example, it is possible to set up a column configuration that covers a wide range of molecular weight, such as additives and monomers to target polymer itself, or a molecular weight range that focuses on low or high molecular weight regions.
A simulation for selecting a column configuration with target molecular weight range can be easily calculated with the APC Column Selector.
High resolution and speed allow not only to acquire more detailed information in a short time, but also to obtain more calibration curve points quickly and easily, thus enabling better characterization analysis. In addition, calibration curves can be created for each analysis to improve data quality and reliability.
Empower 3 software
Empower 3 software is a chromatography data software (CDS) package that allows to acquire data, manage, process, and generate reports. The GPC option to process GPC chromatogram can display polymer data including molecular weight distribution plots in various ways. Based on calibration curves using monodispersed or broad standard samples, this software can automatically calculate not only each average molecular weight such as Mn, Mw, Mz, Mp, Mw/Mn from the sliced molecular weight and easily characterize polymer, but also is flexible software that allow to create customized reports.
Functional electronic polymer materials
Among polymeric materials having high functionality, development of electronics polymer materials is particularly active in recent years. Performance required for each material is different, but because performances different from general-purpose polymers such as coatability, photosensitivity, thermal durability, elasticity, physical strength, light weight, water resistance, oxygen permeability, etc. are required, development is carried out not only from the type and blending ratio of additives but also from the design of the base polymer itself.
By introducing APC technology from the early stage of development, we can understand correlation with other physical test results, difference between development batches etc in more detail and quickly. By controlling the molecular weight distribution peculiar to the polymer material, it is possible to reduce the production cost.
System solution for polymer molecular weight distribution and characterization
ACQUITY APC system
- High speed and high resolution, low dispersion system（https://www.waters.com/waters/library.htm?cid=511436&lid=134729285） (https://www.waters.com/waters/en_IN/ACQUITY-Advanced-Polymer-Chromatography-System—The-Next-Era-in-Polymer-Separation/nav.htm?cid=134724426)
- Optimally designed low dispersion, low noise detectors (Refractive Index detector, Photodiode Array detector, UV / VIS detector, Evaporative Light Scattering detector)（https://www.waters.com/waters/ACQUITY-UPLC-Refractive-Index-Detector/nav.htm?cid=134726507）
- Empower 3 software（GPC option）（https://www.waters.com/waters/Empower-3-Chromatography-Data-Software/nav.htm?cid=10190669）
- ACQUITY APC Column（https://www.waters.com/waters/ACQUITY-APC-Columns/nav.htm?cid=134722533）
- ACQUITY Advanced Polymer Chromatography Calibration Standards Kits（https://www.waters.com/waters/ACQUITY-Advanced-Polymer-Chromatography-Calibration-Standards-Kits/nav.htm?cid=134820439）
- APC column selector（https://www.waters.com/waters/promotionDetail.htm?id=134823417 )