Polycarbonate derived from bisphenol

Table 3. Aromatic Polycarbonates Derived from Bisphenols...

The production of polycarbonates, mostly the aromatic polycarbonates derived from bisphenol A, is the second largest area of phosgene usage and is probably the most important growing area. It accounts for about 1.5 tyr of polycarbonates, corresponding to a yearly phosgene consumption over 0.6 ty. ... 

Bisphenols. See also Bisphenol A (BPA) aromatic polycarbonates derived from, 19 806-808t... 

Physical properties of polycarbonates derived from diphenyl carbonate, and isosorbide and/or bisphenol and those derived from bismethylsalicylcarbonate, (1), bisphenol A and/or isosorbide are provided in Tables 1 and 2, respectively. 

Polycarbonates of numerous bisphenols have been extensively studied. However, most commercial polycarbonates are derived from bisphenol A. At first, both direct-reaction and melt-transesterification processes were employed (Figure 4). In direct-reaction processes, phosgene reacts directly with bisphenol A to produce a polymer in a solution. In transesterification, phosgene is first reacted with phenol to produce diphenyl carbonate, which in turn reacts with bisphenol A to regenerate phenol for recycle and molten, solvent-free polymer. Transesterification is reported to be the least expensive route. It was phased out, however, because of its unsuitability to produce a wide range of products. 

S Polycarbonate (PC). Although the first reported synthesis of aromatic polycarbonates from bisphenol-A can be traced back to Einhom in 1898, there were no additional investigations into this polymer for the next 50 years. Despite numerous investigations into polycarbonates derived from other aromatic diols, the foundation of the polycarbonate industry lies on bisphenol-A. Hereafter, the term PC will refer only to bisphenol-A polycarbonate. Eigure 9.8 shows the structures of the PC polymer and its monomer precursors. 

Kauth et al. (1988) have disclosed transesterification of aromatic polyesters and a polyphosphonate in a devolatiUzing extmder. For example, a polyester derived from bisphenol A and 1 1 iso/terephthalic acid dissolved in dichloromethane/chlorobenzene was devolatilized along with a similar solution of a polyphosphonate derived from methanephosphonic acid and 4,4 -dihydroxybiphenyl in a TSE at 340 °C. The isolated transparent product had a single Tg by DSC and improved impact strength compared to test parts of the individual homopolymers. Polycarbonate and polyestercarbonates were also successfully transesterified with polyphosphonate using this procedure. 

PCs of numerous bisphenols have been extensively studied. However, most commercial PCs are derived from bisphenol A (BPA) and is depicted in Fig. 1.9. Both solution and solvent free, melt-transesterification processes are used to manufacturer polycarbonates. 

Phenol was the 33rd highest-volume chemical. The 1994 U.S. production of phenol was approximately 4 billion pounds. The current world capacity is approximately 15 billion pounds. Many chemicals and polymers derive from phenol. Approximately 50% of production goes to phenolic resins. Phenol and acetone produce bis-phenol A, an important monomer for epoxy resins and polycarbonates. It is produced by condensing acetone and phenol in the presence of HCI, or by using a cation exchange resin. Figure 10-8 shows the Chiyoda Corp. bisphenol A process. 

FIGURE 5 Molecular structures of poly(Bisphenol A carbonate) and poly(Bisphenol A iminocarbonate). The poly(iminocarbonates) are, in a formal sense, derived from polycarbonates by replacement of the carbonyl oxygen by an imino group. 

As an example of the form of the information that may be derived from a pyrolysis-MS, Figure 26 [69] shows the structure of the polycarbonate (PC) and the EI-MS spectra of pyrolysis compounds obtained by DPMS of poly(bisphenol-A-carbonate) at three different probe temperatures corresponding to the three TIC (total ion current) maxima shown in Figure 27(b) Figure 27 compares the MS-TIC curve with those obtained from thermogravimetry. (The TIC trace is the sum of the relative abundances of all the ions in each mass spectrum plotted against the time (or number of scans) in a data collection sequence [70].)... 

The shatterproof glass used in impact-resistant windows is actually not a glass material derived from silicon dioxide. Instead, shatterproof glass is a thermoset plastic or thermoplastic, i.e., a pliable material that is even easier to mold when hot. Shatterproof windows are made using a specific thermoset material known as polycarbonate of bisphenol A (or bisphenol A polycarbonate). This clear,... 

Another large molecule of potential interest would be anions derived from Bisphenolacetone (Figure 8) S)mthesis (Eqn 7), notable reactions to produce polycarbonate (Eqn. 8) or epoxy resins (Eqn. 9). As reviewed recently elsewhere [45]. Bisphenol A (BPA), the s)mthesis of which is shown (Eqn. 7), is a component in the s)mthesis of polycarbonate plastics and epoxy resins (Eqn. 8, 9) that have a variety of significant uses. 

To the range of engineering plastics were added polyethylene and polybutylene tereph-thalates (PET and PBT), as well as General Electric s polyethers, the PPO (polyphenylene oxide) produced through polymerization of 2,6-xylenol and the Noryl plastic produced by blending PPO with polystyrene. Other special polymers, derived like the polycarbonates from bisphenol A, were added to this range polyarylates, polysul-fones, polyetherimides. 

Section 27.13 Most of the applications of polycarbonates center on Lexan, a polyester derived from phosgene and bisphenol A. 

Phenol is a key industrial chemical however, the output of phenol from coal tar is exceeded by that of synthetic phenol. Phenol is used for the production of phenol-formaldehyde resins, while other important uses in the plastics field include the production of polyamides such as nylon, of epoxy resins, and polycarbonates based on bisphenol A and of oil-soluble resins from p-t-butyl and p-octyl phenols. Phenol is used in the manufacture of pentachlorophenol, which is used as a fungicide and in timber preservation. Aspirin and many other pharmaceuticals, certain detergents, and tanning agents are all derived from phenol, and another important use is in the manufacture of 2,4 dichlorophenoxyacetic acid (2,4-D), which is a selective weed killer. 

This class of polymers is obtained by the reaction of diols with carbonic acid derivatives and the most important polycarbonate, PC, is made from bisphenol A and phosgene. 

---