Polycarbonate oligomers

Nelissen [157] has adopted a standard approach for the determination of FRs in polyester compounds (Figure 3.26). The analysis is complicated by spectral interferences of PET/PBT and by the complexity of FR structures, notably DBDPO, Saytex BT 93 W (ethylene-bis-tetrabromophthalimide), PDBS 80, Pyrochek 68PB, Saytex HP7010, Saytex 8010, FR1808, FR 1025, F 2400, BC 52 and BC 58 (brominated polycarbonate oligomers). 

Three flame retardants were compared in this study, namely, a brominated polycarbonate oligomer (58% bromine), a brominated polystyrene (68% bromine), and a brominated triaryl phosphate ester (60% bromine plus 4% phosphorus). These are described in Table I. Figures 1 and 2 compare the thermal stability of the brominated phosphate with commercial bromine-containing flame retardants by thermogravimetric analysis (TGA) and by differential scanning calorimetry (DSC). The brominated phosphate melts at 110°C and shows a 1% weight loss at 300°C. Brominated polycarbonate and brominated polystyrene are polymeric and are not as volatile at elevated temperatures as the monomeric flame retardants. 

Figure 4. Flame Retarding Polycarbonate/PET Polyester Alloy 1. brominated polycarbonate oligomer 2. brominated polystyrene 3. brominated aromatic phosphate ester...

BPA—polycarbonate oligomers, sohd-state polymerization of, 19 818 BPA polycarbonates, 19 808... 

At our 1958 symposium, polycarbonate was introduced. Since then this polymer has reached a domestic production of 50 million pounds per year. J. T. Gregory, J. A. Cook, and A. B. Robertson report on the synthesis of polycarbonate oligomers useful in making random and block copolycarbonates. 

The polycarbonate oligomers were prepared by solution or interfacial techniques (10,17,18). Methylene chloride and tetraethyl ammonium chloride served as the solvent and phase transfer catalyst, respectively. The block copolymerizations were performed essentially under interfacial reaction conditions. In the case of copolymerizations using the Bis-S polysulfone oligomers, it was necessary to use tetrachloroethane as the organic solvent. 

Bis-S-polysulfone oligomer (5.0 g, Mn 5300 by titration) and Bis-A-polycarbonate oligomer (5.0 g, Mn 5000 by UV) were dissolved in 300 mL of tetrachloroethane in a hood. The solution was somewhat hazy even at these concentrations. (By contrast, Bis-A-polysulfone oligomers and Bis-A-polycarbonate oligomer yield clear solutions at comparable... 

Cyclic bisphenol-A polycarbonate oligomers have been reported by Kambour et al. [1994] to be miscible with a broad range of polymers (cohesive energy density, CED = 300 - 500 MJ/m ) (much broader than linear PC). The cyclic oligo-... 

In the examples provided in this section, combinatorial methods were used to improve the properties of an industrial aromatic polymer, such as melt-polymerized bisphenol-A polycarbonate. The reactions were performed in 96-well microtiter glass plates that served as 96-microreactor arrays in a sequence of steps of increasing temperature with a maximum temperature of 280°C. An example of one of the 96-microreactor arrays after melt-polymerization is shown in Figure 5.3A. For melt-polymerization of bisphenol-A polycarbonate, the starting reaction components included diphenyl carbonate and bisphenol-A monomers and a catalyst (e.g., NaOH). The materials codes used in the examples are presented in Table 5.2. Intermediate species include polycarbonate oligomers and phenol. The bisphenol-A polycarbonate polymer often contains a branched side product that produces a detectable fluorescence signal and other species that can include nonbranched end-groups and cyclics. We used fluorescence spectroscopy for nondestructive chemical analysis of melt-polymerized bisphenol-A polycarbonate. The key attractive... 

Tetrabromobisphenol A Polycarbonate Oligomer (Tribromophenyl End Capped) [71342-77-3]. This is a thermally stable resinous solid made from tetrabromobisphenol A and phosgene. It is principally used as a flame-retardant additive for PBT, ABS, and polycarbonate for electrical and electronic apparatus housing. It is available from Great Lakes Chemical as BC-58. 

Figure 6 The copolymerization of polycarbonate oligomers with the [2]catenane 20 to form the poly[2]catenanes 22 to 24.

Xie X Q, Ranade S V and DiBenedetto A T (1999) A solid state NMR study of polycarbonate oligomer grafted onto the surface of amorphous silica. Polymer 40 6297-6306. 

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