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采用2组试验对乙烯酮二聚物的施胶过程进行研究。第1组试验,评价8种乙烯酮二聚物的熔点、蒸气压和相对分子质量对施胶增效速率的影响。实验表明:乙烯酮二聚物的熔点对施胶增效速率具有显著影响;高熔点比低熔点的二聚物在更高的纸页水分下施胶,且达到最终施胶水平也较快;这些结果表明固体和液体乙烯酮二聚物有着不同的施胶增效机理;而蒸气压和相对分子质量对施胶增效速率没有相同影响。第2组试验,在55～85℃干燥温度范围内,测定高熔点的固体乙烯酮二聚物和液体乙烯酮二聚物的准一级施胶增效速率常数。实验表明,随着干燥温度的升高,液体乙烯酮二聚物的速率常数稳定增加,并且由速率常数Arrhenius曲线图可得到45.87kJ/mol活化能。这与内酯环的化学反应是液体乙烯酮二聚物施胶增效的速率决定步骤的结论一致。高熔点的固体乙烯酮二聚物遵循更复杂的动力学原理,其施胶机理由多种机理组合而成。固体和液体乙烯酮二聚物具有不同的施胶效应,可能是由于未反应的和水解的二聚物对施胶的贡献不同。
Two sets of experiments were used to study the sizing process of ketene dimer. In the first set of experiments, the effect of melting point, vapor pressure and relative molecular mass of eight ketene dimers on sizing efficiency was evaluated. The experimental results show that the melting point of ketene dimer has a significant effect on the synergistic rate of sizing; the dimer with a higher melting point than the lower melting point sizing at higher paper moisture and the final sizing level is faster; These results indicate that the solid and liquid ketene dimers have different sizing synergistic mechanisms whereas the vapor pressure and relative molecular weights have no equivalent effect on sizing efficiency. In the second set of experiments, the quasi-first-rate syngas rate constant of the high-melting-point solid ketene dimer and the liquid ketene dimer was determined at a temperature in the range of 55 to 85 ° C. Experiments show that as the drying temperature increases, the rate constant of the liquid ketene dimer increases steadily, and the activation energy of 45.87 kJ / mol can be obtained from the Arrhenius rate constant curve. This is consistent with the conclusion that the chemical reaction of the lactone ring is the rate determining step for the synergism of the liquid ketene dimer. High-melting solid ketene dimers follow more complex kinetic principles and their sizing mechanisms are combined by a variety of mechanisms. Solid and liquid ketene dimers have different sizing effects, possibly due to the different contribution of unreacted and hydrolyzed dimers to sizing.