Polymer Material Characterization

A polymer is a chainlike molecule made up of small molecular units. These small molecular units are called monomers. Monomers of polymer can be joined together either naturally or synthetically. Polymer and small molecules behave very differently, which is mainly due to the molecular weight. A small molecule has a determined small value while a polymer molecule usually has an average value and the value is bigger than small molecule's.

Polymers can be classified according to different criteria. For example, depending on the source, the polymer can be divided into natural polymers and synthetic polymers. Both natural and synthetic polymers play significant roles in our daily life. The most commonly used natural polymer is cellulose which is an important source of textile industry and the demands are still increasing. Synthetic polymers have been used everywhere in our life, such as car tires/bumpers, water pipelines, some drinking cups, containers, cellphone, clothes and shoes. According to their properties, polymer can be divided into three groups: plastic, rubber and fiber. Each type of polymer has its own unique properties. It can be selected according to the requirements in practical application.

Fig. 1. The examples of polymers.

The most basic reaction of synthetic macromolecules consists of two types: condensation polymerization and addition polymerization. The monomer structure, polymerization mechanism and specific polymerization methods of these two kinds of synthetic reactions are different.

Different reaction mechanisms will correspond to different synthesis methods such as bulk polymerization, solution polymerization and emulsion polymerization. The obtained products of each polymerization have different performance and can be applied in different areas. If a polymer is expected to be used in mass production, the properties are very critical. For example, if a new developed rubber is expected to produce car tires, the physical and chemical properties of this material must meet the requirements.

Alfa Chemistry offers polymer characterizations for:

• Plastics: PP/PE/PST, etc.

• Rubbers: EPR/ABS/IIR, etc.

• Polymer adhesive/ glue

• Polymer coating

• Polymer based composites

With professional knowledge of the various types of polymer materials, as well as an understanding of the dependence of their behaviors on the characteristics, scientists and engineers at Alfa Chemistry can provide many testing services about composite materials. Here are some examples.

• A differential scanning calorimeter (DSC) is a thermoanalytical technique that can be used to measure heat capacity, identify unknown polymer/additives (blends, fillers, plasticizers, process aids), estimate crystallinity percentage, determine process temperatures (cure, injection/extrusion/thermoforming molding, heat welding), and monitor aging/oxidation effects, etc. It provides the thermal properties (heat capacity, glass transition Tg, crystallization degree) of a polymer.

• Gel Permeation Chromatography (GPC), also known as Size Exclusion Chromatography, is used to determine the relative molecular weight of polymer samples as well as the distribution of molecular weights. The distribution of molecular weights is a very important parameter that will determine the performance of a polymer material, such as tensile strength, adhesive strength and melt viscosity.

• Thermal Gravity Analysis (TGA) is a method of thermal analysis in which the mass of a sample is measured over time as the temperature changes. This measurement provides information about physical phenomena, such as phase transitions, absorption and desorption; as well as chemical phenomena including chemisorptions, thermal decomposition, and solid-gas reactions.

• Universal testing machine is used to test the tensile strength and compressive strength of polymer materials.

• Fourier Transform Infrared Spectroscopy (FTIR) can be used to measure the inter/intra molecular interactions of PP/PE/PS.

• X-ray fluorescence (XRF) is used to determine the elements of a polymer.

• Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) are very powerful instruments that can reveal the microscopic information of a polymer.

• HPLC and MS are extractable and leachable for an uncertain polymer.

Alfa Chemistry is professional in polymer material characterizations and we can provide accurate and reliable tests results within the time constraint. We have conducted failure analysis, small batch test trials, competitor analysis, physical/chemical/mechanical analysis, extractable and leachable for different polymer materials. Please feel free to contact us if you have any concern or would like us to perform any polymer material testing. Check our instruments list for our capabilities.