Polycarbonate commercially available

The range of polycarbonates commercially available has increased greatly in recent years. The main differences between these grades are largely due to ... 

Polyarylates can be blended with a wide range of commercially available thermoplastics, including polyamides, polycarbonates, polyetherketones, polyesters, and poly(phenylene sulfide), thus broadening their application domain. 

Polybutadienes, polycaprolactones, polycarbonates, and amine-terminated polyethers (ATPEs) are shown in Scheme 4.4 as examples of other commercially available polyols. They are all specialty materials, used in situations where specific property profiles are required. For example, ATPEs are utilized in spray-applied elastomers where fast-reacting, high-molecular-weight polyamines give quick gel times and rapid viscosity buildup. Polycarbonates are used for implantation devices because polyuredtanes based on them perform best in this very demanding environment. Polycaprolactones and polybutadienes may be chosen for applications which require exceptional light stability, hydrolysis resistance, and/or low-temperature flexibility. 

The pores in a commercially available polycarbonate filtration membrane (Poretics) were used as templates to form the nanotubules (pore diameter = 50 nm pore density = 6 X 10 pores cm thickness = 6 pm). As before, the electrolessly plated Au deposits both on the pore walls and the membrane faces [71]. The gold surface layers on the membrane faces allow us to make electrical contact to the Au nanotubules within the pores. The thickness of the gold layers deposited on the pore walls can be controlled... 

The electroless plating procedure described above was used to plate the Au nanotubules into the pores of commercially available polycarbonate track-etch filters [Osmonics, 6 pm thick, pore dia. = 50 nm (28 nm-dia. Au tubules) or 30 nm (all other Au tubules), 6 X 10 pores cm ]. The... 

The photoablation process consists of the absorption of a short-wavelength laser pulse to break covalent bonds in polymer molecules and eject decomposed polymer fragments. Channels of various geometries and dimensions can be obtained using an appropriate mask. Many commercially available polymers can be photoablated, including polycarbonate, poly(methyl methacrylate) (PMMA), polystyrene, nitrocellulose, poly(ethylene terphtalate) (PET), and poly(tetrafluoroethylene) (Teflon). ... 

A number of the polymers considered previously—polycarbonate, aramid, and polyary-late—were among the first commercial successes in the efforts to synthesize polymers with increasingly high use temperatures. In the following sections we will discuss some of the other commercially available heat-resistant polymers followed by a consideration of research efforts to move further up in the temperature scale. 

Cyclic carbonates are not commercially available and have to be synthesized prior to use. As a result, commercially available carbonates such as diethyl carbonate [55-57] or diphenyl carbonate [93] were evaluated in polycondensation reactions with diols to prepare polycarbonates since they allow a broader spectrum of polymers to be accessed. Unfortunately, polymerizations employing diethyl carbonate require the use of an excess diethyl carbonate [55]. Nevertheless, polymers with molecular weight of 40kDa were achieved within 16 h. Also, the polymerization of diphenyl carbonate with butane-1,4-diol or hexane-1,6-diol via the formation of a cyclic dimer produced polymers with molecular weights ranging from 119 to 339kDa [93]. 

To determine if the tensile properties of the commercially available polycarbonate from 4, 4 -isopropylidenediphenol were similarly affected, several of the antiplasticizers were also added to this polymer. The bisphenol itself is commonly known as bisphenol A. 

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. 

Abstract Makrolon , a commercially available polycarbonate with a glassy ultramicroporous structure (mean pore-volume 0.1 nm3), was often employed as sensitive layer for optical sensors in recent years. Due to the definite pore volume-distribution, it can be used as a size-selective sensitive layer. The interaction behaviour of Makrolon of different layer-thicknesses under the influence of methanol, ethanol and 1-propanol is characterized by Spectral El-lipsometry (SE), Surface Plasmon Resonance Spectroscopy (SPR)... 

The most commonly used hard templates are anodic aluminum oxide (AAO) and track-etched polycarbonate membranes, both of which are porous structured and commercially available. The pore size and thickness of the membranes can be well controlled, which then determine the dimension of the products templated by them. The pores in the AAO films prepared electrochemically from aluminum metals form a regular hexagonal array, with diameters of 200 nm commercially available. Smaller pore diameters down to 5 nm have also been reported (Martin 1995). Without external influences, capillary force is the main driving force for the Ti-precursor species to enter the pores of the templates. When the pore size is very small, electrochemical techniques have been employed to enhance the mass transfer into the nanopores (Limmer et al. 2002). 

Microdialysis probes are now commercially available in various sizes, designs and materials. Microdialysis probes can be flexible for soft peripheral tissues and fluids or rigid for brain. Four probe geometries are available linear, loop, side-by-side and concentric. The semipermeable membrane is generally chosen as long as possible, typically between 1 and 10 mm. The probe radius is generally chosen as small as possible, typically between 200 and 400 im O.D. to cause minimal disturbances within the tissue. Dialysis probes are made of various materials (for example celluloses and copolymers like polyacetonitrile/sodium methallyl sulfonate and polycarbonate/ether). The molecular mass cut off (5-50 kDa), inertness and permeability to solutes of the probes could be different. 

---