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Investigation of the Performance and Properties of a New Generation Additives with Dual Purpose, Cell Opening and Delay Action Catalyst; in MDI and Polyester Polyol Based PU System

Karimi Dastenaei, Mohammad Reza | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54063 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Shojaei, Akbar; Moghimi, Abolghasem
  7. Abstract:
  8. Polyurethanes are polymers prepared by the reaction of polyols with isocyanates. Due to the wide range of raw materials from which polyurethanes are synthesized, as well as their various applications, they are classified into several groups, of which polyurethane foams are one of the most important products that have significant consumption. One of the most important diisocyanates is methylene diphenyl diisocyanate and also one of the most commonly used polyols in the polyurethane industry are polyesters.In addition, chain extenders, catalysts and suitable additives such as foaming agents, surfactants, fillers, etc., are all raw materials that participate in the production of polyurethane foam. One of the most important goals of using conventional catalysts is to increase the speed of the gelling and blowing reaction and to balance the two, so that ultimately, the production time of the polyurethane production process and consequently the molding time is reduced.A common problem in the polyurethane molding industries, is the rapid onset of component reactions immediately after mixing, which can lead to problems such as blockage of injection lines, improper filling of large and complex molds, and so on. Occur. On the other hand, in many cases, the amount of catalyst cannot be reduced, because it increases the production time of polyurethane and slows down production and increases costs. It should be possible to use materials that slow down the reaction at first but do not adversely affect the overall process and production time. Polyurethane cell opener additives are used in low-density foam to prevent volume shrinkage after molding the product and also to create properties such as foam permeability.In this study, the use of polybutadiene-acrylonitrile copolymer in order to achieve both delaying in reaction and opening the foam cells, with acceptable results has been presented. This additive has acidic groups in its polymer chain (functionality about 2) and the amount of acrylonitrile monomer is insignificant. Acidity and long polymer chain, delayed the performance of tertiary amine catalysts and opened of foam cells, respectively
  9. Keywords:
  10. Cell Opener ; Delay Action Catalyst ; Acid-Blocked Tertiary Amine Catalyst ; Polyurethane Foam ; Methylene Diphenyl Diisosyanate

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