Polycarbonate mechanical strength

Poly (iminocarbonates) are little known polymers that, in a formal sense, are derived from polycarbonates by the replacement of the carbonyl oxygen by an imino group (Fig. 5). This backbone modification dramatically increases the hydrolytic lability of the backbone, without appreciably affecting the physicomechanical properties of the polymer the mechanical strength and toughness of thin,... 

The major features for advanced photo-systems relative to the base film are a small-size thrust cartridge and return inside the cartridge. These features require low core-set curl values and high mechanical strength. The cellulose triacetate (CTA), polycarbonate and PET materials currently used in the photographic industry are not able to satisfy these requirements. Some newly developed film materials, such as modified-PET and syndiotactic polystyrene, were also unable to satisfy such requirements. It is known that annealing films just below the Tg (BTA treatment) could reduce core-set curl tendencies. BTA treatments of... 

Requirements for CD-quality material are polycarbonate with low levels of chemical impurities, low particle levels, thermal stability, excellent mold release, excellent clarity, as well as constant flow and constant mechanical behavior (for reproducibility). There exists a time/cost balance. High molecular weight polycarbonate offers a little increase in physical property but the flow rate is slow, making rapid production of CDs difficult. The molecular weight where good mechanical strength and reasonable flow occurs, and that allows for short cycles, is in the range of 16,000-28,000 Da. 

The MF membranes are usually made from natural or synthetic polymers such as cellulose acetate (CA), polyvinylidene difiuoride, polyamides, polysulfone, polycarbonate, polypropylene, and polytetrafiuoroethylene (FIFE) (13). Some of the newer MF membranes are ceramic membranes based on alumina, membranes formed during the anodizing of aluminium, and carbon membrane. Glass is being used as a membrane material. Zirconium oxide can also be deposited onto a porous carbon tube. Sintered metal membranes are fabricated from stainless steel, silver, gold, platinum, and nickel, in disks and tubes. The properties of membrane materials are directly reflected in their end applications. Some criteria for their selection are mechanical strength, temperature resistance, chemical compatibility, hydrophobility, hydrophilicity, permeability, permselectivity and the cost of membrane material as well as manufacturing process. 

Second 1950 1965 High-density polyethylene, isotactic polypropylene, polycarbonate, polysulfones, linear polyesters, synthetic rubbers Improved mechanical strength... 

Polyetherimide (Ultem 1000, GEC) is a high performance engineering thermoplastic with high heat distortion temperature (> 200°C), high mechanical strength and inherent flame-retardancy characteristics. Recently blends of polyetherimide with polycarbonate have been commercially offered as thermoformable sheets and as molding compounds (Table 15.28). The primary reason for... 

Apart from these, CS membranes find applications in the field of hemodialysis. The excellent fitm-forming nature and high mechanical strength of CS membranes made it a suitable candidate for hemodialysis application. For example, chitosan-poly(ethylene oxide) blend membranes showed improved permeability and blood compatibility due to their hydrophilic and porous nature [28]. However, the cellulosic membranes and synthetic membranes (made up of polyaryle-thersulfone, polyamide, PVP, polycarbonate, and PAN) have a well-established hemodialysis field as compared to CS-based membranes. 

In most materials, small amoimts of moisture will cause a change in the polymer s melt viscosity which, in turn, will affect the way it processes. When polymers, such as polycarbonate and polyester, are heated above the melt temperature, small amounts of moisture in the pellets or on the surface will cause a chemical reaction. This reaction can degrade the polymer, changing its molecular weight, melt viscosity, and mechanical strength. Larger amounts of moisture may result in a rough and scaly surface finish and even bubbles and voids in the product. 

Polycarbonate (PC) has excellent mechanical strength, particularly impact strength, good electrical properties and transparency, and is widely utilised in a variety of fields including office machinery, electric and electronic machinery, automobiles, architecture and so on. Many applications require that a PC composition be flame retardant(s) (FR) and combine ease of processing with good optical properties. Table 2.7 illustrates some of the physical properties of PC. 

Polycarbonate possesses high mechanical strength, high thermal stability, transparency, good dielectric properties, thanks to which it is finding wide use in various branches of industry. It was shown in [22] that the thermal decomposition of polycarbonate, analogous to certain polyarylates, begins at temperatures above 400°C and is accompanied... 

Finally, CarboSil and ChronoSil are thermoplastic polysiloxane/polycarbonate/ PU copolymers able to combine the mechanical strength of polycarbonate-based PUs with the biostability and hemocompatibihty of siloxane-based PUs. These products are also resistant to environmental stress aacking and therefore suitable for long-term cardiovascular applications. 

Thus poly(p-xylene carbonate) has been synthesized from potassium carbonate and p-xylene dibromide under the influence of 18-crown-6-ether. The crown ether formed a complex with the metal cation, thereby providing highly reactive unsolvated anions. Aromatic polycarbonates have been prepared and subjected to studies of their heat stability, mechanical strength, transparency, and electrical properties. Spiro o-carbonates have been synthesized and their poly-racrizability, by cationic initiation, has been assessed. 

Polycarbonate has good mechanical strength, is heat resistant, has dimensional stability, and is widely used as a general purpose engineering plastic. However, its viscosity, chemical resistance, and dependence of impact strength on wall thickness are not suitable for some applications. Idemitsu alloys are highly-functional polycarbonate-based polymer alloys. While retaining the best properties of polycarbonate the as above mentioned problems have been virtually eliminated. 

Polycarbonate Panlite L-1250 High mechanical strength Electrical parts Teijin Chemicals Ltd. 

Parts molded from polycarbonate can be cleaned, disinfected, and sterilized by most methods known in practical operation. With some materials, caution is advisable if aldehydes or phenols are active ingredients. Under certain conditions, damage in the form of stress-cracks can occur under contact with cleaning, disinfectant, and sterilizing media. They result in a reduction in mechanical strength. Moreover, there also other effects not always visible, such as initial swelling or chemical degradation in the plastic that can also impair mechanical properties. 

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