Study On The Time-of-flight Mass Spectronmetry Of Phenolic Resin Under Different Synthesis Conditions

Phenolic resin is the first synthetic resin, which was synthesized one hundred years ago. Becauase of its raw materials is easy to get, synthetic convenience and good performance, it is widely used in industry, such as molding compounds, coatings, friction materials, foundry resins, adhesives, etc.With the development of industry, higher demands for phenolic resin have been proposed, such as higher decomposition temperature, good wear resistance, sufficient toughness and strength, etc. Furthermore, people pay more attentoin to material flammability, low smoke and low toxicity, so the applications of phenolic resin are limited, which make people look at the ancient material again. Although the synthesis of phenolic resins is mature and it is widely used in actual production, no one can get the absolute its molecular weight and guess the structure of monomer connection in different reactions, because of the complexity of synthesis and other factors. If we can get the absolute molecular weight of phenolic resins, its structure of monomer connection and the key synthesis factors of high-ortho novolak resin, we will be able to control the production of high-ortho novolak resin and solve the problem fundamentally.In this paper, under the guide of novolac reaction principle in polymer chemistry and refering to a lot of papers, we synthesized general novolac, high-ortho novolak resin and novolac synthesized in ionic liquids successfully, which are more concerned and representative to the study on the synthesis process of novolac. The products have been characterized by means of infrared absorption spectrum(IR), nuclear magnetic resonance(1H-NMR and 13C-NMR), time of flight mass spectrometry (MALDI-TOF-MS) and gel permeation chromatography(GPC). The results of IR showed that the as-prepared novolac was target and the relative proportion of o-methylene and p-methylene. The results of 1H-NMR and 13C-NMR showed that the synthesized novolac was target further and the percentage of o-o methylene, o-p methylene and p-p methylene. The results of NMR were consistent with those of IR. The results of MALDI-TOF-MS showed that the absolute molecular weight, the molecular weight distribution, and the possible structure of different polymerization degree novolac through its terminal group. In the paper, the absolute molecular weight and the weight distribution were determined for the first time by MALDI-TOF-MS. Combining with the percentage of o-o methylene, o-p methylene, p-p methylene and branched structure from the 13C-NMR, we obtained the possible structure of phenolic resin, which created conditions for the synthesis of high-ortho novolak resin and established the theoretical foundation for the synthesis mechanism of phenolic resin and its more extensive applications.