Resins percent conversion

Although reactivity ratios indicate that VP is the more reactive monomer, reaction conditions such as solvent polarity, initiator type, percent conversion, and molecular weight of the growing radical can alter these ratios (138). Therefore, depending on polymerization conditions, copolymers produced by one manufacturer may not be identical to those of another, especially if the end use appHcation of the resin is sensitive to monomer sequence distribution and MWD. 

V. P. Gupta and W. J. M. Douglas [AIChE J., 13 (1967) 883] carried out the isobutylene hydration reaction with excess water in a stirred tank reactor utilizing a cationic exchange resin as the catalyst. Use the following data to determine the effectiveness factor for the ion exchange resin at 85°C and 3.9 percent conversion. 

Thus, the percent conversion of the monomer resin to cured polymer is given by ... 

Important insights regarding the interrelationship of exposure time and Iq have been reported for photoinitiated crosslinking (by radical polymerization) of highly functional acrylated resins. Based on simultaneous differential scanning calorimetry (DSC) and thermomechanical analysis (TMA), these elegant studies demonstrate that percent conversions are limited by rapid formation of highly crosslinked domains with immobilized radicals, the reactivity of which is essentially unaffected by continued irradiation. Conversions increased with temperature, as expected for thermal mobilization of the trapped radicals. 

The agreement between experimental data and those predicted by Equations 2.16 and 2.17 is very good, but it has been verified only up to 20 percent of conversion and only for a specific type of resin. 

The main by-products are 1-chlorobutadiene, produced from the residual dichloro 2-butenes or formed during the reaction, polymers, sodium chloride and monochloro-butenes (l-chloro 1-butene, 2-diloro 2-butenes, 2-chloro 1-butene, etc.) To control the undesirable polymerizations, the reaction takes place in an oxygen-free environment, at the lowest possible temperature, and with an inhibitor. Also effective is the presence of a solvent (methanol, ethanol) or a catalyst In this case, however, it is necessary to raise the caustic soda concentrations (30 per cent) or to employ other bases (liquid ammonia, ion exchange resins, etc.). In the absence of catalyst, the residence time is 3 to 5 h. and selectivity exceeds 95 molar percent for a once-through conversion of nearly 95 per cent... 

The polymerization kinetics were studied via time-conversion relationships at different dose rates (Figures 6-9). The radiation curing was carried out at room temperature in closed aluminum capsules. Percent monomer conversion was determined gravimetrically for N-vinylpyrrolidone. Evaporation was accomplished under vacuum in a ventilated oven at 50 °C until the weight was constant. For butyl methacrylate and polyester resins, the residual monomer content was determined by gas chromatographic analysis after immersion of the cured products in acetone. 

Cyanate esters also function as epoxy converters. Incorporating 50-65 percent epoxy resin will provide essentially complete conversion at 177°C. 

Kawase (1966) used simulated moving-bed reactor for production of phenethyl acetate from acetic acid and phenethyl alcohol with ion exchange resin Amberlyst 15 as catalyst. They proved that flow rates and temperature were the most important factors to achieve almost 100% conversion. Lode et al. (2001) used a simulated moving-bed reactor for recovery of dilute acetic acid from wastewater, by esterification with methanol in presence of ion exchange resin catalyst. They found that the overall efficiency of acetic acid recovery was about 96 percent. 

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