Bisphenol temperature maximum

High-resolution thermogravimetry has been successfully utilised to investigate the thermal degradation of the bisphenol-A poly(sulfone) [a.l98]. The degradation parameters of the bisphenol-A poly(sulfone), involving temperature, maximum decomposition rate, char yield at 800 °C, activation energy, reaction order and frequency factor, exhibit a... 

Figure 23. Stress-relaxation curves of amorphous bisphenol A polycarbonate at the different temperatures shown by the curves. The numbers in brackets are the maximum deformations used in the tests. (From Ref. 217.)...

For maximum heat resistance, pyromellitic dianhydride is often used. The composition and properties of metal-to-metal adhesives based on a combination of epoxy novolac and a bisphenol A epoxy resin have been described in Sec. 12.5.1. Depending on the cure temperature and the choice of amine curing agent, strength as high as 3000 psi at room temperature and over 1000 psi in the range of-55 to + 150°C is possible. 

Figures 14 and 15 show the relations between the amount of iron arene initiator, the reaction enthalpy (AHj and the glass transition temperature Tg of the polymerized Bisphenol-A diglycidylether (cf. Table 2, structure I, x = 0.15) and the oligomer product based on the former compound (cf. Table 2, structure I, x = 11.8). The maximum polymerization heat per mole of epoxide is observed ivith an initiator concentration of 1.5-2.5% (w/w). At this concentration, Tg of the crosslinked resin is about 115 °C for the polymerized low-molecular-weight expoxide and about 80 "C for the polymerized high-molecular-weight epoxide resin.

The reaction could not be carried out with the usual sulfonic acid ion-exchange resin, because its maximum use temperature was 120°C. The product cannot be made directly from acetone and aniline owing to the formation of a dihydroquinoline by-product (from two molecules of acetone and one of aniline). A shape-selective zeolite might allow the reaction to take place without formation of this byproduct. An inexpensive way of making this diamine from acetone and aniline, similar to the preparation of bisphenol A from acetone and phenol, could lead to new families of polyamides, polyimides, polyureas, polyurethanes, and epoxy resins. A palladium catalyst supported on Nafion dimerized ethylene much faster in water than in organic solvents. The butene was easy to separate.18... 

It has been asserted (14) that above their melting points, the structural relaxation times in polymer fluids would be much less than 10" sec. This proved to be true for molten PE. However, for polyethylene oxide (PEO) a temperature of maximum loss was observed at approximately 60°C at a frequency of 6.06 GHz (J5). The melting point of PEO is near 60°C. The temperature of maximum loss for bisphenol-A polycarbonate (16) was 280°C at a frequency of 5.43 GHz. The melting point of bisphenol-A polycarbonate is 240°C. Thus any general correlation between Tm and structural relaxation in fluids seems unwarranted. 

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... 

Polysulfones are a family of engineering thermoplastics that exhibit excellent high-temperature properties. Many variations of this material have a continuous use temperature of 150 C and a maximum temperature of around 170 C. Polysulfones are produced by the Friedel-Crafts reaction of sulfonyl chloride groups with aromatic nuclei, or by reacting 4,4 -dichlorodiphenylsulfone with alkali salt of bisphenol A. The latter polycondensation is conducted in highly polar solvents, such as dimethylsulfoxide or sulfolane. These materials can be injection molded into complex shapes and can compete with many metals. The following is the chemical structure ... 

The bisphenol A novolac epoxy resin is a non-ionic aqueous dispersion of a polyfunctional aromatic epoxy resin. It contains reactive epoxide functionality and is intended for high performance applications which require maximum chemical and solvent resistance and/or elevated temperature service. This thixotropic dispersion contains no organic solvent and is completely water reducible. Upon evaporation of water, the novolac epoxy coalesces to... 

Recently, because high-performance epoxy resin is strict in its requirements, polyfunctional epoxy has been offered in practical fields. In particular, epoxy novolac resin (ENR) is largely used as electronic encapsulation material because of its well-known thermal resistance properties. Because the strucmres of ENR exert a significant influence on the properties of the cured resins, it is necessary to understand their structure-property relationship. Despite various advantages, epoxy needs modifications to overcome some crucial disadvantages like limited solubility in polar solvents, higher cost of bisphenol A-based epoxy and maximum service temperature of only about 100 °C. 

Polymers that show a rate maximum with respect to temperature in the pure state do so also when crystallizing from diluent mixtures.(42a,67,88) Two examples are shown in Figs. 13.32 and 13.33 for isotactic poly(styrene) crystallizing from ether benzophenone or dimethyl phthalate respectively.(42a,67) Characteristically, the addition of the diluent causes a shift of the crystallization range to lower temperatures. A similar effect was observed with bisphenol-A poly(carbonate).(88) In addition, the growth rate maximum increases with the initial addition of diluent. This phenomenon is observed up to about 20% diluent in the case of benzophenone (Fig. 13.32) and about 50% with dimethyl phthalate (Fig. 13.33). A similar pattern is also indicated for the poly(carbonate)-diluent mixture.(89) With further additions of diluent there is a continuous decrease in the growth maxima up to very dilute... 

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