The Importance of Polymer Characterization
Polymer characterization studies focus on establishing the molecular structure, mass, and morphology of synthetic and natural polymeric materials. These are comprised of concurrent structures, or chains, of covalently-bonded macromolecules. The thermodynamic and mechanical properties of these structures vary depending upon their chemical or biological composition, but they typically emerge as high-versatility materials with a range of interdisciplinary applications. Natural polymers include materials such as wool and rubber, while synthetic polymers are primarily comprised of plastics such as polythene and polystyrene.
Polymer and Water Vapor Interactions
Water vapor permeation of polymer products can cause significant structural and mechanical damage, necessitating accurate analysis of a polymer’s vapor sorption properties. Gravimetric methods can be used to precisely measure vapor-solid interactions for polymer characterization, analyzing changes in sample molecular mass using sorption isotherms and diffusion coefficients.
Multiple kinetic parameters such as pressure and temperature can be controlled and monitored to a fine degree throughout, with continuous sample weight measurement. Intelligent equilibration methods ensure that accurate results are acquired from automatically measured isotherms, providing precise insights into hygroscopic swelling, mechanical instability, and immobilization of polymer chains. These are all primary concerns for many polymer characterization applications, providing insights into the viability of both synthetic and organic materials.
Polymer Characterization for Solvent Interactions
Organic solvents also interact with polymers, permeating the molar structure and solvating it to degrade the product’s mechanical stability.
Modern gravimetric analyzers can perform organic solvent flow measurements for polymer characterization to help quantify their polymorphic qualities. Polymer characterization methods can determine amorphous phase conditions of plastics under distinct thermodynamic conditions. Analysts use these equilibrium isotherms to qualify the usability of polymers in specific atmospheric conditions. These are fundamental for further polymer characterization of gas and vapor interactions, illuminating a materials’ potential hydrophobicity and adsorption.
Gas Sorption in Polymers
Gas species can also interact with porous polymers such as polymers of intrinsic microporosity (PIMs) and hybrid organic-inorganic membranes. Gas sorption measurements allow the simultaneous determination of gas uptake, also referred to as gas solubility, and gas transport, sometimes called gas diffusivity.
Applications of Polymer Characterization
Polymer characterization through gravimetric methods has an enormous range of applications. It enables highly-accurate quality control of plastic materials such as polymer thin films for packaging of fast-moving consumer goods such as pharmaceuticals and healthcare products. Electronics, construction, and energy all rely on accurate polymer characterization to improve product performances and ensure their continued operation at expected standards.
Emerging materials such as graphene-based polymers, bio-mimetic membranes and mixed matrix membranes inherently rely on gravimetric sorption techniques to quantify gas and vapor permeability and sorption or solubility of these exciting new products.
Gravimetric Polymer Characterization with Hiden Isochema
Research and quality control using gravimetric polymer characterization requires instruments with excellent long-term stability, to ensure experimental parameters are maintained throughout multiple kinetic and thermodynamically sensitive experiments. This also ensures that results obtained from the characterization are accurate, consistent and repeatable.
Hiden Isochema provides a range of gravimetric instruments and permeation analyzers for polymer characterization applications, including:
- IGA-002: a high resolution, single-component gravimetric gas and vapor sorption analyzer with unrivalled versatility;
- IGAsorp: an automated dynamic vapor sorption (DVS) analyzer for operation with unparalleled measurement precision;
- XEMIS-002: an advanced gravimetric gas and vapor sorption analyzer capable of operating with corrosive vapor species, and at gas pressures up to 170 bar.
- The MBR membrane permeation analyzer, for directly measuring selective gas permeation through polymeric membranes under various composition conditions.