Solvent resistance tests

Fig. 19.9 Structure-property relationships in BPA-HQ-RS copolymers measured using developed high-throughput screening approach. Relation between HQ monomer concentration and BPA-HQ-RS copolymer solvent-resistance measured as the normalized frequency shift of sensor response for different levels of RS and BPA. Solvents (a, b) THF, (c, d) chloroform, (e, f) MEK. RS monomer a, c, and e. BPA monomer b, d, and f. Error bars, 1 SD from three replicate solvent-resistance testes. Reprinted with permission from Potyrailo et al.23 Copyright 2006 American Chemical Society...

Low Temperature Properties. The property of solvent resistance makes fluorosihcone elastomers usefiil where alternative fluorocarbon elastomers cannot function. The abiHty to retract to 10% of their original extension after a 100% elongation at low temperature is an important test result. Eluorosihcones can typically pass this test down to —59°C. The brittle point is approximately —68°C. 

All resins except polybutadiene formulated with conventional melamine cross-linkers, applied to SAE 1010 bare steel paint test panels, and baked to yield cross-linked, solvent resistant films. 

Effects of BPA, HQ, and RS on solvent-resistance were further established by relating resistance of BPA-HQ-RS compositions to THF, chloroform, and MEK solvents. The structure-property relationships in BPA-HQ-RS copolymers established using the developed high-throughput screening approach are summarized in Fig. 19.9. The solvent-resistance of BPA-HQ-RS copolymers was plotted as a function of HQ monomer concentration because HQ had the strongest effect on solvent-resistance (Fig. 19.8). At maximum tested HQ concentration of 40%, the solvent resistance was the best for all tested solvents. Also, different concentrations of BPA (40 and 60%) and RS (0 and 20%) did not affect the solvent resistance, while without... 

Desirable blend properties are impact strength (withstand drop test at -29°C), solvent resistance and weatherability. Blends predominantly used include impact-modified PA (6 and 66), PC/PEST and PC/ABS. 

Ritter et al. have synthesized a variety of (meth)acrylamides in good yields from (meth)acrylic acid and aliphatic and aromatic amines under solvent-free microwave irradiation conditions [14]. It was found that addition of a polymerization initiator (AIBN) to the reaction mixture led directly to poly(meth)acrylamides in a single step. In these polymerization procedures, 11.6 mmol methacrylic acid was mixed with 11.6 mmol amine and 0.58 mmol AIBN in a pressure-resistant test tube. The tubes were sealed and irradiated in a single-mode microwave reactor for 30 min at 140 W (Scheme 14.4). The experiments were performed without temperature control and were not compared with conventional conditions. 

Solvent Resistance. Solvent resistance has been tested by the so-called MEK rubbing test on very thin coatings with thickness in the range of 0.2-0.3 mils. 

For cigarette burn resistance test, a lit cigarette is placed horizontally on the coating surface for 1 min. The tested area is cleaned with water and suitable solvent and then examined for change in surface appearance or visible aspects of coating. 

Blends of a PAI and poly(aryl ether ketone) exhibit improved solvent resistance and hydrolytic stability. Blends of sulfonated poly(ether ether ketone) and PAI have been tested as membrane materials for direct methanol fuel cells. Miscible blends can be obtained. Blends of poly(urethane)s (PU)s and PAI, as the minor component have been reported for membrane applications. The resulting membranes are immiscible. Phase separation occurs when the amount of PU decreases. 

The water and organic solvent resistance was tested and the solubility in water, ethanol and acetone was evaluated (Table 6). 

The test most widely used in the printed-circuit industry to measure the efficiency of a cleaning process is the resistivity of solvent extracts test known as ROSE. According to this test, after the assembly has been cleaned, the part is flushed with a solution of 75% isopropanol and 25% deionized water and the electrical resistivity of the extracts measured. Ionic residues dissolved in the extracts reduce the resistivity of the original... 

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