Polycarbonate blends

Standard polycarbonate, (PC), is made from bisphenol A and phosgene via an interfacial polymerization process. The polymer backbone has an aromatic polycarbonate structure with a recurring carbonate, moiety which, uniquely accounts for the outstanding toughness of the polycarbonate and the rigid aromatic unit contributes to its high glass transition temperature. 

Although a large number of applications of polycarbonate have been based on its unique combination of high impact strength, heat resistance and clarity there are still a few property deficiencies 

lack of an adequate low temperature notched Izod impact strength  

lack of an adequate solvent resistance and stress crack resistance (Table 15.23)  

hmited long-term hydrolytic stability at elevated temperatures  

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Triphenyl phosphate [115-86-6] C gH O P, is a colorless soHd, mp 48—49°C, usually produced in the form of flakes or shipped in heated vessels as a hquid. An early appHcation was as a flame retardant for cellulose acetate safety film. It is also used in cellulose nitrate, various coatings, triacetate film and sheet, and rigid urethane foam. It has been used as a flame-retardant additive for engineering thermoplastics such as polyphenylene oxide—high impact polystyrene and ABS—polycarbonate blends. 

General Electric now also offer polyetherimide-polycarbonate blends. Although these materials are not transparent and have a lower specification than the basic polyetherimide, they are less expensive and find use in microwave oven trays and automotive reflectors. 

The range of blends now available comprises a broad spectrum of materials superior in many respects, particularly heat deformation resistance, to the general purpose thermoplastics but at a lower price than the more heat-resistant materials such as the polycarbonates, polyphenylene sulphides and polysulphones. At the present time the materials that come closest to them in properties are the ABS/ polycarbonate blends. Some typical properties are given in Table 21.1. 

In multiphase polymeric systems, the properties of the end products do not solely depend on the properties of the pure components, but other various parameters also have a great impact (Fig. 1). In order to emphasize these factors, the following systems are taken into consideration (I) elastomer toughened styrene system, (2) elastomer toughened polycarbonate blends, and (3) direct reactive blend processing. 

Heterogeneous compatible blends of preformed elastomers and brittle plastics are also an important route for the development of blends of enhanced performance with respect to crack or impact resistance. Polycarbonate blends with preformed rubber particles of different sizes have been used to provide an insight into the impact properties and the fracture modes of these toughened materials. Izod impact strength of the blends having 5-7.5 wt% of rubber particles exhibits best overall product performance over a wide range temperature (RT to -40°C) [151-154]. 

Polycarbonate-ABS blends, 19 824-825 Polycarbonate blends, 20 361-362 Polycarbonate-polyester blends, 19 824, 825 Polycarbonate resin(s)... 

B. Perret and B. Schartel, The effect of different impact modifiers in halogen-free flame retarded polycarbonate blends - ii. fire behaviour, Polym. Degrad. Stab., In Press, Corrected Proof, 2009. 

P.D. Phelps, E.P Boden, G.C. Davis, D.R. Joyce, and J.F. Hoover, Silicone-polycarbonate block copolymers and polycarbonate blends having reduced haze, and method for making, US Patent 5530083, assigned to General Electric Company (Schenectady, NY), June 25,1996. 

Acrylic -polycarbonate blends [POLYCARBONATES] (Vol 19) - [FIBERS-ACRYLIC](Vol 10) - [FIBERS - CELLULOSE ESTERS] (Vol 10) - [COATINGS] (Vol 6) - [FIBERS-REGENERATEDCELLULOSICS](Vol 10) -m friction materials [BRAKE LININGS AND CLUTCH FACINGS] (Vol 4)... 

Some of these block copolymers have improved low temperature impact strength and higher stress-crack resistance than neat BPA polycarbonate Blends. The concept of blending two or more commercially available materials to create a new material having properties different from either starting material has generated a great deal of interest. Polycarbonate blends are used to tailor performance and price to specific markets. 

Kolarik J, Lednicky F, Locati G, Fambri L (1997) Ultimate properties of polycarbonate blends effects of inclusion plastic deformation and of matrix phase continuity. Polym Eng Sd 37 128-137... 

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