Polycarbonate materials properties

A Comparison of Polyiminocarbonates and Polycarbonates The Effect of the NH Group on Polymer Properties. The replacement of the carbonyl oxygen by an NH group presents the only molecular difference between polyiminocarbonates and polycarbonates. In spite of the overall structural similarity between these two types of polymers, we found very significant differences between their respective material properties. In general, polyiminocarbonates and polycarbonates tend to complement each other in several aspects. 

It is essential to devote particular care to the quality and properties of the surfaces many plastics may be metallized direct but the results in practice generally are unsatisfactory except for acrylic and polycarbonate materials. With films especially, any surface contours and defects will be reproduced faithfully in the reflective coating applied. It is for such reasons that the surfaces usually are prepared by the application of a lacquer base coat as described— even, in some instances, by primer or pre-base coat lacquers. These help to ensure satisfactory adhesion, fill small defects or voids in the surface of the underlying film or moulding, and provide the smooth surface essential for an effective metallic layer. 

Plastics that are commonly processed by extrusion include acrylics (polymethacrylates, polyacrylates) and copolymers of acrylonitrile cellulosics (cellulose acetate, propionate, and acetate butyrate) polyethylene (low and high density) polypropylene polystyrene vinyl plastics polycarbonates and nylons. The material properties and extrusion properties have been reviewed by Whelan and Dunning.Additives that may be included to modify or enhance proper-ties include lubricants and antislip agents to assist processing during extrusion plasticizers to achieve softness and flexibility stabilizers and antioxidants to retard or prevent degradation and dyes and pigments. 

Material property Si (single crystal) Glass Si02 PDMS pmma " Parylene e Polycarbonate... 

Early developments in aliphatic and aromatic polycarbonates. The first significant documentation of aromatic polycarbonates synthesis began with Einhom [24]. He reacted hydroquinone, resorcinol, and catechol with phosgene in a pyridine solution, obtaining linear polymers from hydroquinone (an insoluble crystalline powder that melted above 280°C) and resorcinol (an amorphous material that melted with decomposition at 190 to 200°C), and a cyclic carbonate from catechol. Subsequent research was focused on finding more efficient preparation methods and on improving material properties [25]. 

BPA polycarbonates exhibit properties typical of aromatic polyesters with respect to flame resistance. Early on, flame resistance was enhanced in these materials by introducing tetrabromo BPA/BPA copolymers [48]. Although other, more sophisticated systems— particularly nonhalogenated ones— have since been discovered and commerciahzed, these brominated copolymers are still in use. 

D. Pi eitag, G. Pi engler, and L. Morbitzer, Routes to New Aromatic Polycarbonates with Special Material Properties, Angew. Chem. Int. Ed. Engl. 30 1598 (1991). 

Data obtained from the Lexan Polycarbonate Resin Property Guide, GE Advanced Materials. 

Functionalization of more polar hydroxytelechelic polymers with the synthon resulted in comparably spectacular changes in material properties. Functionalized polyether is a material with a broad rubber plateau in DMTA, and a storage modulus of 10 MPa, whereas the starting material is a viscous liquid. The properties of functionalized polyester and functionalized polycarbonate are those of semicrystalline polymers, whereas the starting materials are very brittle. 

Of practical interest are detailed studies to influence the magnetooptical properties of RE-TM materials by the substrate material and the substrate adhesion of RE-TM layers by the selected deposition technique (226). Accordingly, measurements have been performed on glass, BPA-polycarbonate, and poly(ethylene terephthalate) (as a flexible substrate). 

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