Intertek determines the birefringent properties of a wide range of optical materials materials for clients. However, when these materials are subjected to stresses from extrusion, stretching and injection, blow molding processes, or even post manufacturing unintentional damage, the induced stress shows up as birefringence in the finished materials. A polymer molecular chain has a polarizability anisotropy originated from its three-dimensional chemical structure. 'Double Refraction' is another way to describe Birefringence. Whether your business is local or global, we can ensure your products meet quality, health, environmental, safety, and social accountability standards for virtually any market around the world. Learn More, Evaluating how your products and services meet and exceed quality, safety, sustainability and performance standards. Polymer Testing, Inspection, and Problem Solving Brochure (PDF), Testing of Plastics, Elastomers, Composites and Film Brochure (PDF), G Mark Requirements for Electronics Imported to the Gulf Member States, Pilot Plant Processing for Polymers and Plastics, Physical and Mechanical Testing of Polymers, Polymer Regulatory and Consulting Services, Polymer Product Processing Development Support, Microbeads and Microplastics Testing and Consultancy, Coatings and Thin Films Analysis and Testing, Adhesives Analysis and Formulation Testing. Approaches The analysis can be performed on large parts or with small parts under magnification. Learn More, Validating the specifications, value and safety of your raw materials, products and assets. Examples of isotropic solids are glass, table salt (sodium chloride, illustrated in Figure 1(a)), many polymers, and a wide variety of both organic and inorganic co… liquid containers, packaging films, consumer product packaging) and high performance plastics (e.g. B: orientation, exhibiting birefringence. Intertek is the industry leader with over 46,000 people in 1,000 locations in over 100 countries. Polymer Engineering & Science 2014 , 54 (9) , 2097-2111. Website best viewed with IE 9+, Chrome, Firefox and Safari. speed of light in vacuo speed of light in sample c n v = = The refractive index varies linearly with the polarizability of the bonds in the sample. Design of zero-zero-birefringence polymers in methacrylate copolymer systems containing trichloroethyl methacrylate. These polymers are subject to the same handling stresses as petrochemical plastics and as such will exhibit polymer birefringence in the same way. The birefringence is often quantified as the maximum difference between refractive indices exhibited by the material. Learn More, Formally confirming that your products and services meet all trusted external and internal standards. Optical birefringence allows for a non-destructive qualitative assessment of residual or molded-in stress of transparent materials and parts by examining a sample between cross polarizers. Using birefringence to understand the physical properties of these new materials can help establish usage parameters and lifetime predictive characteristics. Figure 3. Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. Polymer birefringence is predominately the result of manufacturing processes. birefringence. If the composition or orientation of the polymer varies throughout the thickness the laboratory will not pick this up, and the sample should have at least one flat surface on which measurements can be made. This effect is achieved by combining suitable amounts of … Birefringence is close to zero even in injection-molded plates of the polymer. Birefringence Analysis of Polymers. Birefringence, or double refraction, is the difference in the refractive index of light along two perpendicular directions in a material. Contact us to see how Hinds Instruments works with our customers to solve complex metrology problems. Optical birefringence allows for a non-destructive qualitative assessment of residual or molded-in stress of transparent materials and parts by examining a sample between cross polarizers. To parse the two mechanisms of light retardation, polycrystalline spherulites of polylactide enantiomers were analyzed by Mueller matrix microscopy. Polymer Birefringence. Many transparent solids are optically isotropic, meaning that the index of refraction is equal in all directions throughout the crystalline lattice. Biopolymers are polymers, films and bulk plastics sourced from agricultural or biological materials rather than petrochemical sources. Our website uses cookies to ensure that we give you a good experience. Spectral studies of Donepezil release from streched PVA polymer films. Our scientists examine the nature of the high and low areas of a material's birefringence in order to aid development scientists and engineers improve process specifications, and to improve overall yield; the benefit of which will manifest in the areas of high volume and high performance plastics. DOI: 10.1002/app.39136. Birefringence is formally defined as the double refraction of light in a transparent, molecularly ordered material, which is manifested by the existence of orientation-dependent differences in refractive index. Most polymer plastics are inherently isotropic and as such would not show birefringence in an unstressed state. The circular birefringence of polycrystalline polymers is invariably obscured by strong linear birefringence. The phenomenon is commonly observed in some crystals. Exicor® MT for inline manufacturing of bulk polymer films process and quality control, Exicor® 150AT for the quality control or research laboratory setting, Exicor® product line - Kerr Constant measurement system for evaluation of block co-polymers, R&D Evaluation of Polymer Structure Using Birefringence. We thought that, during photoelastic birefringence generation, the α-CH3 group of the MMA unit hinders the rotation of the benzene ring of St units that are adjacent to MMA units. Birefringence in polymer films measures polymer orientation, which is related to physical properties of the films. A typical optical setup is shown in . The dispersion of birefringence in oriented amorphous polymers is discussed. Minimisation of birefringence is important in processing polymers for applications such as CD and DVD manufacturing. Most polymer plastics are inherently isotropic and as such would not show birefringence in an unstressed state. Journal of Applied Polymer Science 2013, 130 (1) , 138-144. Birefringence (Double Refraction) Testing of Plastic and Polymeric Materials for high volume and high performance materials. Birefringence makes use of the refractive index, n, of a material, as defined below.