Polysulfone, oligomers

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... 

Two-phase, yet optically transparent, glass-glassy block copolymers can be produced from polycarbonate and polysulfone oligomers either by increasing average block weight beyond 16,000 g/mol or by increasing... 

The reaction takes place in the organic phase (tetrachloroethane or CHCl ) between the hydroxyl terminated polysulfone oligomer and the terephthaloyl chloride. Thus, this technique is not an interfacial technique in that the reaction is not taking place at the interface but the by-product (HCl) crosses the interface into the aqueous phase. 

The phenolic end groups of the polysulfone oligomers were potentio-metrically titrated to find the number average molecular weight using tetramethylammonium hydroxide. The oligomers were dissolved in freshly distilled NMP and then titrated by a method developed in our laboratory... 

The limiting viscosity number, [ri]dl/g, of the polysulfone oligomers and segmented copolymers were found using a Cannon-Ubbelohde (number 50) dilution viscometer at 25.0 0.01 C with chloroform as the solvent. 

Starting Polysulfone Oligomer Mole % Added Blphenol % Yield... 

Table 4. Interfacially Synthesized Segmented Copolymers Based on 5350 Polysulfone Oligomer...

Figure 1. FT-IR spectra of hydroxyl terminated polysulfone oligomer and segmented copolymer.

Figure 2. FT-IR spectras of polysulfone oligomer and segmented copolymers.

GPC and intrinsic viscosities were used as an indication of the molecular weight increase obtained by reaction of the polysulfone oligomer with the acid chloride to form the segmented copol3rmer. Figure 3 contains GPC... 

In order to incorporate the polyarylester segments into the polysulfone, we chose to simply extend the interfacial procedure used by Conix. This is accomplished by replacing some of the bisphenol-A with a hydroxyl-terminated polysulfone oligomer as outlined in Equation 4. As can be seen, several parameters such as the molecular weight of the polysulfone oligomer, the over-all polyester-polysulfone composition, and the acid chloride composition can all be varied. It is important, however, that the polysulfone oligomer be hydroxyl-terminated and that the molecular weight be known accurately since this reaction is stoichiometric. 

Copolymerizations were carried out interfacially in a laboratory Waring blender. A typical reaction was conducted as follows To a stirred solution of 1.5 g sodium hydroxide in 200 ml water in the blender was added 3.500 g of bisphenol-A. Then, 2.0 g tetraethyl ammonium chloride was added, followed by 150 mJl of methylene cjiloride. A solution of 9.900 g of a -10,000 gm/mole (Mn) polysulfone oligomer in 100 ml methylene chloride was then introduced. Next, a solution of 3.3172 g of terephthaloyl chloride in 100 mH of methylene chloride was added to the reaction mixture and stirred vigorously. Agitation was stopped after approximately 5 minutes of... 

Number-average molecular weights ("Rn) of several of the polysulfone oligomers were measured using chloroform solutions at 40 C with a Wescan model 233 vapor phase osmometer. Sucrose octaacetate was used to calibrate the instrument. 

The copolymers listed in Tables 1 and 2 comprise two series. In the first series (Table 1), a polysulfone oligomer of 6,000 g/mole was utilized. The sulfone-ester composition was held constant at 50-50 weight ratios while the composition of the polyester block itself was varied from 100% isophthalate to 100% terephthalate. At the extremes of composition (Samples I-l, 1-2, 1-7), the... 

---