Bisphenol crystallization

Bisphenol F Resin. Bisphenol F [2467-02-9] epoxy resin is of the same general stmcture as the epoxy phenol novolaks. Bisphenol F is 2,2Emethylene bisphenol. Whereas the epoxy phenol novolaks vary from viscous Hquids to soHd materials, the bisphenol F resin has a low viscosity (ca 4 Pa-s (40 P)) and 165 epoxy equivalent weight. Its n value (degree of polymerization) is about 0.15 and crystallization, often a problem with low viscosity conventional bisphenol A resins, is reduced with the bisphenol F resin. 

Yet another recent development has been the alloying of polycarbonates with liquid crystal polymers such as Vectra (see Section 25.8.1). These alloys are notable for their very good flow properties and higher strength and rigidity than conventional bisphenol A polycarbonates. 

Recent developments have allowed atomic force microscopic (AFM) studies to follow the course of spherulite development and the internal lamellar structures as the spherulite evolves [206-209]. The major steps in spherulite formation were followed by AFM for poly(bisphenol) A octane ether [210,211] and more recently, as seen in the example of Figure 12 for a propylene 1-hexene copolymer [212] with 20 mol% comonomer. Accommodation of significant content of 1-hexene in the lattice allows formation and propagation of sheaf-like lamellar structure in this copolymer. The onset of sheave formation is clearly discerned in the micrographs of Figure 12 after crystallization for 10 h. Branching and development of the sheave are shown at later times. The direct observation of sheave and spherulitic formation by AFM supports the major features that have been deduced from transmission electron and optical microscopy. The fibrous internal spherulite structure could be directly observed by AFM. 

The major uses of BPA are in the production of polycarbonate resins (63%) and epoxy resins (27%). Polycarbonates have major outlets in automotive parts, compact discs, eyeglasses, and sheet and glazing applications, and have caused bisphenol A consumption to more than double during the past decade. Epoxy resins are two-component adhesives for very strong bonding. Miscellaneous uses include flame retardants (mostly tetrabromobisphenol A) and other polymer manufacture. Polycarbonate grade bisphenol A is >99% p,p isomer. The epoxy grade is 95% p,p. The p,p and o,p isomers can be separated by a combination of distillation and crystallization. 

Statistical copolymerization of ethylene glycol and 1,4-butanediol with dimethyl ter-ephthalate results in products with improved crystallization and processing rates compared to poly(ethylene terephthalate). Polyarylates (trade names Ardel, Arylon, Durel), copolymers of bisphenol A with iso- and terephthalate units, combine the toughness, clarity, and proce-sibility of polycarbonate with the chemical and heat resistance of poly(ethylene terephthalate). The homopolymer containing only terephthalate units is crystalline, insoluble, sometimes infusible, and difficult to process. The more useful copolymers, containing both tere- and isophthalate units, are amorphous, clear, and easy to process. Polyarylates are used in automotive and appliance hardware and printed-circuit boards. Similar considerations in the copolymerization of iso- and terephthalates with 1,4-cyclohexanedimethanol or hexa-methylene diamine yield clear, amorphous, easy-to-process copolyesters or copolyamides,... 

Crystallization behavior in miscible blends containing crystallizable components has been extensively studied [174-180]. Generally, when a crystallizable component is mixed with an amorphous component its melting temperature goes down and its crystallinity lowers. The same trend has been reported for blends with intercomponent hydrogen bonding such as PCL/STVPh [181], PCL/poly(hydroxyl ether of bisphenol A) [182] and phenoxy resin/PEO [183]. 

The Tm of PCs is decreased from 225 to 195 C when the methyl pendant groups in bisphenol A are replaced by propyl groups. This is due to the added volume occupied by the propyl groups which act against both crystallization and compact inter-chain structure. 

The blend of poly(bisphenol A carbonate)-(poly(caprolactone) PC-PCL is particularly unusual in that both polymers are capable of crystallization and FT-IR has been used to study the state of order in these blends as a function of the method of preparation 254,255). In this case, PCL is a macromolecular plasticizer for PC. The PCL becomes progressively less crystalline as the concentration of PC increases. PC is amorphous if the blend is cast from methylene chloride but semicrystalline if cast from tetrahydrofuran. When PC in the pure form is exposed to acetone, it will not crystallize, but in the blend, exposure of acetone causes the PC to crystallize which emphasizes the additional mobility of the PC in the blend. 

In the early literature it is suggested that polycarbonates can be easily plasticized with common plasticizers. Plasticization of polycarbonate has been investigated by Kozlov et al. (12). These authors described the influence of plasticization on softening points and mechanical properties of bisphenol A polycarbonates. They conclude that the behavior of plasticized polycarbonate is similar to that encountered for most amorphous polymers. The influence of crystallization effects promoted by the plasticizer was not taken into account. 

The object of this study was to investigate more closely the influence of a plasticizer on the crystallization behavior of bisphenol A polycarbonate and to deduce some fundamental thermodynamic properties of the polymer. 

Bisacodyl. 4,4 -(2-Pyridylmethylene)bisphenol diacetate [603-50-9] (Dulcolax) (9) is a white to off-white crystalline powder in which particles of 50 Jim dia predominate. It is very soluble in water, freely soluble in chloroform and alcohol, soluble in methanol and benzene, and slighdy soluble in diethyl ether. Bisacodyl may be prepared from 2-pyridine-carboxaldehyde by condensation with phenol and the aid of a dehydrant such as sulfuric acid. The resulting 4,4 -(pyridylmethylene)diphenol is esterified by treatment with acetic anhydride and anhydrous sodium acetate. Crystallization is from ethanol. 

These solvents include tetrahydrofuran (THF), 1,4-dioxane, chloroform, dichloromethane, and chlorobenzene. The relatively broad solubility characteristics of PSF have been key in the development of solution-based hollow-fiber spinning processes in the manufacture of polysulfone asymmetric membranes (see Hollow-fibermembranes). The solvent list for PES and PPSF is short because of the propensity of these polymers to undergo solvent-induced crystallization in many solvents. When the PES structure contains a small proportion of a second bisphenol comonomer, as in the case of RADEL A (Amoco Corp.) polyethersulfone, solution stability is much improved over that of PES homopolymer. 

Gross, S. M. Roberts, G. W. Kiserow, D. J. DeSimone, J. M. Crystallization and Solid State Polymerization of Poly(bisphenol A carbonate) Facilitated by Supercritical C02. Macromolecules 2000, 33, 40 -5. 

Komiya et al. [13] recently introduced the novel, environmentally friendly process from Asahi Chemical Industry Co. for the production of polycarbonates, which requires neither phosgene nor solvent (Scheme 1). In this process bisphenol A undergoes a prepolymerization with diphenyl carbonate in the melt. A simple crystallization of the prepolymer is fol-... 

The lower-viscosity grades have an EEW of about 175 and are virtually pure diglycidyl ethers of bisphenol A. They are so pure, however, that they will crystallize on storage. The crystals melt on warming above 40°C, and heating can be used to restore a crystallized resin to its previous form. Special crystallization-free resins systems have been formed by blending low-viscosity DGEBA resins with more conventional bisphenol A-based epoxy resins. 

Bisphenol F resins are often mixed with conventional DGEBA epoxy resins because of the relatively high cost of the bisphenol F product. When mixed with bisphenol A resins, the two form crystallization-free resins of moderate viscosity. 

Description In the bisphenol reaction section (1), acetone is reacted with excess phenol in multiple fixed-bed reactors, containing a DOWEX resin catalyst, to form BPA and water. The outlet from the reactors is fed to the adduct crystallizers (2) where a crystal adduct... 

Reticulate composites comprising needles of TTT-TCNQ (tetrathiotetra-cene-tetracyaiioquinodimethane) in poly(bisphenol-A-carbonate) were first described in the early 1980s. The composites were prepared by casting thin films from a solution of the components in o-dichloromethane. The composite contained a network of fine interconnected needle crystals of the CT salt and had a percolation threshold of 2-3 mass% of the CT salt, as shown in Fig. 8.22. 

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