Sulfone resin temperature

Figure 2. TICA temperature scan of the AT sulfone resin in (a) nitrogen environment and in (b) air.

However, the curves in Figure 2 shows that while the nitrogen cure shows a vitrification temperature of the sulfone resin at 208°C the corresponding air scan vitrification temperature is 222 >C. 

Because of the lower glass transition temperature of the precured sulfone resin, the viscosity of the reactive resin during the scan was low. This may have helped the diffusion of air through the sample, thus accentuating the difference between the air and nitrogen scan results. 

Figure 3. Isothermal cure results of the sulfone resin at 170 The time tjj is the time where the resin had a glass transition temperature equal to the cure temperature.

Figure 5. Time to vitrification of the sulfone resin as a function of temperature.

Figure 6. Temperature scan of the sulfone resin after curing in nitrogen at 131 °C for 4 hours. The temperature was scanned down when a maximum temperature of 350 was reached.

Figure 13. Plot of Tg of the sulfone resin at different cure temperature. All specimens had been cured for 4 hours.

Zhou et al. (2001, 2003) dip coated resol-type phenohc resin and a novalak-type sulfo-nated phenolic resin/phenolic resin mixture onto porous a-alumina tubes. The membranes were then pyrolyzed at various temperatures in a nitrogen purge. As expected, the separation performance depended on pyrolysis temperature. The sulfonated resin had much better separation performance with both high O2 permeance (240 GPU for 500°C CMS) and reasonably attractive selectivity (O2/N2 = 5.2). 

The typical acid catalysts used for novolak resins are sulfuric acid, sulfonic acid, oxaUc acid, or occasionally phosphoric acid. Hydrochloric acid, although once widely used, has been abandoned because of the possible formation of toxic chloromethyl ether by-products. The type of acid catalyst used and reaction conditions affect resin stmcture and properties. For example, oxaUc acid, used for resins chosen for electrical appHcations, decomposes into volatile by-products at elevated processing temperatures. OxaUc acid-cataly2ed novolaks contain small amounts (1—2% of the original formaldehyde) of ben2odioxanes formed by the cycli2ation and dehydration of the ben2yl alcohol hemiformal intermediates. 

An important aspect of this procedure is the use of latent acid catalysts, such as phenyl hydrogen maleate, phenyl trifluoracetate, and butadiene sulfone. These catalysts reduce the peak exotherm from over 200°C to 130—160°C. The resin catalyst mixture has a working life of up to several days at RT. The elevated temperature of mol ding these latent catalysts generates the corresponding acids, namely, maleic, trifluoracetic, and phenolsulfonic, which cataly2e the resole reaction. Typically, a cycle time of 1—2 min is requited for a mold temperature of - 150° C. 

Eor more demanding uses at higher temperatures, for example, in aircraft and aerospace and certain electrical and electronic appHcations, multifunctional epoxy resin systems based on epoxy novolac resins and the tetraglycidyl amine of methylenedianiline are used. The tetraglycidyl amine of methylenedianiline is currently the epoxy resin most often used in advance composites. Tetraglycidyl methylenedianiline [28768-32-3] (TGALDA) cured with diamino diphenyl sulfone [80-08-0] (DDS) was the first system to meet the performance requirements of the aerospace industry and is still used extensively. 

Both sulfuric acid and hydrofluoric acid catalyzed alkylations are low temperature processes. Table 3-13 gives the alkylation conditions for HF and H2SO4 processes. One drawback of using H2SO4 and HF in alkylation is the hazards associated with it. Many attempts have been tried to use solid catalysts such as zeolites, alumina and ion exchange resins. Also strong solid acids such as sulfated zirconia and SbFs/sulfonic acid resins were tried. Although they were active, nevertheless they lack stability. No process yet proved successful due to the fast deactivation of the catalyst. A new process which may have commercial possibility, uses... 

Tests showed that a fluid loss additive on a base of a sulfonated tannic-phenolic resin is effective for fluid loss control at high temperature and pressure, and it exhibits good resistance to salt and acid [868]. 

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