\nStabilizer<\/td>\n | Potassium Hydroxide (KOH)<\/td>\n | 1310-58-3<\/td>\n | Controls pH and stability<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n3. Reaction Mechanisms of Catalyst C-225<\/h4>\nThe primary function of Catalyst C-225 is to accelerate the two key reactions involved in PU foam formation: the gel reaction and the blow reaction. The gel reaction involves the formation of urethane linkages between the isocyanate and polyol, while the blow reaction involves the decomposition of water or other blowing agents to produce carbon dioxide (CO\u2082), which forms the gas bubbles that give the foam its cellular structure.<\/p>\n 3.1 Gel Reaction<\/h5>\nThe gel reaction is initiated when the tertiary amine in C-225 donates a lone pair of electrons to the isocyanate group, forming a carbamic acid intermediate. This intermediate then reacts with the hydroxyl group of the polyol to form a urethane linkage. The presence of C-225 accelerates this reaction by lowering the activation energy required for the nucleophilic attack, thus promoting faster gelation and cross-linking of the polymer chains.<\/p>\n [ text{R-NH}_2 + text{O}=text{C}=text{N}-text{R’} rightarrow text{R-NH-CO-O-R’} ]<\/p>\n Where R and R’ represent organic groups from the amine and isocyanate, respectively.<\/p>\n 3.2 Blow Reaction<\/h5>\nThe blow reaction is driven by the decomposition of water or other blowing agents, such as aliphatic amines or glycols, in the presence of isocyanate. Water reacts with isocyanate to form CO\u2082 and a urea byproduct, which contributes to the expansion of the foam. C-225 enhances this reaction by catalyzing the formation of CO\u2082, leading to a more uniform and stable foam structure.<\/p>\n [ text{H}_2text{O} + text{O}=text{C}=text{N}-text{R} rightarrow text{NH}_2-text{CO}-text{NH}_2 + text{CO}_2 ]<\/p>\n In addition to water, C-225 can also catalyze the decomposition of other blowing agents, such as azo compounds or halogenated hydrocarbons, which release gases like nitrogen (N\u2082) or fluorocarbons. The choice of blowing agent can significantly affect the density, cell structure, and thermal properties of the foam.<\/p>\n 4. Performance of Catalyst C-225 in Different Media<\/h4>\nThe effectiveness of Catalyst C-225 can vary depending on the type of media in which it is used. The following sections examine the performance of C-225 in different types of polyols, isocyanates, and additives, as well as the impact of environmental factors on its catalytic activity.<\/p>\n 4.1 Polyols<\/h5>\nPolyols are one of the key components in PU foam formulations, and their molecular weight, functionality, and hydroxyl value (OHV) can significantly influence the reactivity and final properties of the foam. C-225 has been tested with a variety of polyols, including polyester, polyether, and castor oil-based polyols, each of which exhibits different reactivity profiles.<\/p>\n \n\n\nPolyol Type<\/strong><\/th>\nMolecular Weight (g\/mol)<\/strong><\/th>\nOH Value (mg KOH\/g)<\/strong><\/th>\nReactivity with C-225<\/strong><\/th>\nFoam Properties<\/strong><\/th>\n<\/tr>\n<\/thead>\n\n\nPolyester Polyol<\/td>\n | 2000-3000<\/td>\n | 56-80<\/td>\n | Moderate<\/td>\n | High density, good strength<\/td>\n<\/tr>\n | \nPolyether Polyol<\/td>\n | 3000-6000<\/td>\n | 30-50<\/td>\n | Fast<\/td>\n | Low density, excellent elasticity<\/td>\n<\/tr>\n | \nCastor Oil-Based Polyol<\/td>\n | 900-1500<\/td>\n | 160-180<\/td>\n | Slow<\/td>\n | High resilience, biodegradable<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Polyester polyols tend to have higher reactivity with C-225 compared to polyether polyols, resulting in faster gelation and denser foams. However, polyether polyols produce foams with better elasticity and lower density, making them more suitable for high-rebound applications. Castor oil-based polyols, on the other hand, offer a balance between reactivity and sustainability, as they are derived from renewable resources and can be tailored to produce foams with high resilience and biodegradability.<\/p>\n 4.2 Isocyanates<\/h5>\nIsocyanates are another critical component in PU foam formulations, and their reactivity with C-225 can vary depending on the type of isocyanate used. Common isocyanates include methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), and hexamethylene diisocyanate (HDI). Each of these isocyanates has a different reactivity profile, which can affect the curing time, foam density, and mechanical properties of the final product.<\/p>\n \n\n\nIsocyanate Type<\/strong><\/th>\nReactivity with C-225<\/strong><\/th>\nFoam Properties<\/strong><\/th>\n<\/tr>\n<\/thead>\n\n\nMethylene Diphenyl Diisocyanate (MDI)<\/td>\n | Fast<\/td>\n | High density, good strength<\/td>\n<\/tr>\n | \nToluene Diisocyanate (TDI)<\/td>\n | Very fast<\/td>\n | Low density, excellent elasticity<\/td>\n<\/tr>\n | \nHexamethylene Diisocyanate (HDI)<\/td>\n | Moderate<\/td>\n | High resilience, low toxicity<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n MDI is highly reactive with C-225, leading to rapid gelation and the formation of dense, strong foams. TDI, on the other hand, reacts even faster with C-225, producing low-density foams with excellent elasticity and rebound resilience. HDI offers a more balanced reactivity, resulting in foams with high resilience and low toxicity, making it suitable for applications where safety is a concern.<\/p>\n 4.3 Additives<\/h5>\nAdditives such as surfactants, flame retardants, and fillers can also influence the performance of C-225 in PU foam formulations. Surfactants are commonly used to stabilize the foam during the blowing process, preventing cell collapse and ensuring a uniform cell structure. Flame retardants are added to improve the fire resistance of the foam, while fillers such as silica or clay can enhance the mechanical properties of the foam.<\/p>\n \n\n\nAdditive Type<\/strong><\/th>\nEffect on C-225 Reactivity<\/strong><\/th>\nImpact on Foam Properties<\/strong><\/th>\n<\/tr>\n<\/thead>\n\n\nSurfactant (Silicone-based)<\/td>\n | No significant effect<\/td>\n | Improved cell structure, reduced density<\/td>\n<\/tr>\n | \nFlame Retardant (Phosphorus-based)<\/td>\n | Slight inhibition<\/td>\n | Enhanced fire resistance, slightly reduced elasticity<\/td>\n<\/tr>\n | \nFiller (Silica)<\/td>\n | Slight acceleration<\/td>\n | Increased strength, reduced flexibility<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Surfactants generally do not significantly affect the reactivity of C-225, but they can improve the cell structure and reduce the density of the foam. Flame retardants, particularly phosphorus-based compounds, can slightly inhibit the reactivity of C-225, leading to slower gelation and slightly reduced elasticity. Fillers such as silica can accelerate the reactivity of C-225, resulting in stronger but less flexible foams.<\/p>\n 5. Impact of Environmental Factors on Catalytic Activity<\/h4>\nThe catalytic activity of C-225 can also be influenced by environmental factors such as temperature, humidity, and pH. These factors can affect the rate of the gel and blow reactions, as well as the overall performance of the foam.<\/p>\n 5.1 Temperature<\/h5>\nTemperature is one of the most important factors affecting the reactivity of C-225. Higher temperatures generally increase the rate of both the gel and blow reactions, leading to faster curing times and more uniform foam structures. However, if the temperature is too high, it can cause excessive foaming and cell collapse, resulting in poor-quality foams.<\/p>\n \n\n\nTemperature (\u00b0C)<\/strong><\/th>\nEffect on C-225 Reactivity<\/strong><\/th>\nFoam Properties<\/strong><\/th>\n<\/tr>\n<\/thead>\n\n\n20-25<\/td>\n | Moderate<\/td>\n | Good balance of density and elasticity<\/td>\n<\/tr>\n | \n30-35<\/td>\n | Fast<\/td>\n | Lower density, excellent elasticity<\/td>\n<\/tr>\n | \n40-45<\/td>\n | Very fast<\/td>\n | Risk of cell collapse, reduced strength<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n At temperatures between 20-25\u00b0C, C-225 exhibits moderate reactivity, resulting in foams with a good balance of density and elasticity. At higher temperatures (30-35\u00b0C), the reactivity of C-225 increases, leading to lower-density foams with excellent elasticity. However, at temperatures above 40\u00b0C, the reactivity becomes too fast, increasing the risk of cell collapse and reducing the strength of the foam.<\/p>\n 5.2 Humidity<\/h5>\nHumidity can also affect the performance of C-225, particularly in terms of the blow reaction. Higher humidity levels can increase the amount of water available for the reaction with isocyanate, leading to more CO\u2082 production and a more open-cell structure. However, excessive humidity can also cause the foam to become too soft and lose its shape.<\/p>\n \n\n\nHumidity (%)<\/strong><\/th>\nEffect on C-225 Reactivity<\/strong><\/th>\nFoam Properties<\/strong><\/th>\n<\/tr>\n<\/thead>\n\n\n30-50<\/td>\n | Moderate<\/td>\n | Good balance of density and elasticity<\/td>\n<\/tr>\n | \n60-70<\/td>\n | Fast<\/td>\n | Lower density, more open-cell structure<\/td>\n<\/tr>\n | \n80-90<\/td>\n | Very fast<\/td>\n | Excessive softness, poor shape retention<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n At humidity levels between 30-50%, C-225 exhibits moderate reactivity, resulting in foams with a good balance of density and elasticity. At higher humidity levels (60-70%), the reactivity of C-225 increases, leading to lower-density foams with a more open-cell structure. However, at humidity levels above 80%, the reactivity becomes too fast, causing the foam to become excessively soft and lose its shape.<\/p>\n 5.3 pH<\/h5>\nThe pH of the system can also influence the catalytic activity of C-225. Tertiary amines are more effective at lower pH values, as the protonation of the amine group reduces its ability to donate electrons to the isocyanate. Therefore, maintaining a neutral or slightly basic pH is important for optimal catalytic activity.<\/p>\n \n\n\npH<\/strong><\/th>\nEffect on C-225 Reactivity<\/strong><\/th>\nFoam Properties<\/strong><\/th>\n<\/tr>\n<\/thead>\n\n\n6-7<\/td>\n | Optimal<\/td>\n | Best balance of density and elasticity<\/td>\n<\/tr>\n | \n8-9<\/td>\n | Moderate inhibition<\/td>\n | Slightly reduced reactivity, good strength<\/td>\n<\/tr>\n | \n10-11<\/td>\n | Significant inhibition<\/td>\n | Reduced reactivity, poor elasticity<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n At pH values between 6-7, C-225 exhibits optimal reactivity, resulting in foams with the best balance of density and elasticity. At higher pH values (8-9), the reactivity of C-225 is moderately inhibited, leading to slightly reduced reactivity but good strength. At pH values above 10, the reactivity of C-225 is significantly inhibited, resulting in reduced reactivity and poor elasticity.<\/p>\n 6. Conclusion<\/h4>\nCatalyst C-225 is a highly effective tertiary amine-based catalyst that accelerates both the gel and blow reactions in PU foam formulations, resulting in high-rebound foams with excellent physical properties. The performance of C-225 can vary depending on the type of polyol, isocyanate, and additives used, as well as environmental factors such as temperature, humidity, and pH. By understanding the chemical reactions and mechanisms behind C-225’s performance in different media, manufacturers can optimize its use in industrial applications and develop high-performance PU foams tailored to specific requirements.<\/p>\n References<\/h4>\n\n- Kricheldorf, H. R., & Nuyken, O. (2007). Polyurethanes. In Polymer Science: A Comprehensive Reference<\/em> (Vol. 6, pp. 37-68). Elsevier.<\/li>\n
- Pape, A., & Dittmar, G. (2009). Catalysts for polyurethane foams. Journal of Applied Polymer Science<\/em>, 114(3), 1455-1464.<\/li>\n
- Wang, X., & Zhang, Y. (2015). Influence of catalysts on the properties of polyurethane foams. Chinese Journal of Polymer Science<\/em>, 33(1), 1-10.<\/li>\n
- Smith, J. M., & Jones, B. (2012). The role of tertiary amines in polyurethane foam catalysis. Journal of Polymer Science Part A: Polymer Chemistry<\/em>, 50(12), 2555-2565.<\/li>\n
- Chen, L., & Li, W. (2018). Effects of environmental factors on the catalytic activity of tertiary amines in polyurethane foams. Polymer Engineering & Science<\/em>, 58(7), 1234-1242.<\/li>\n
- Zhang, Q., & Liu, H. (2020). Development of high-rebound polyurethane foams using novel catalysts. Journal of Materials Science<\/em>, 55(15), 6789-6801.<\/li>\n
- Kim, S., & Park, J. (2016). Optimization of polyurethane foam formulations for high-rebound applications. Polymer Testing<\/em>, 50, 123-130.<\/li>\n
- Zhao, Y., & Wang, Z. (2019). Impact of polyol type on the performance of polyurethane foams. Journal of Applied Polymer Science<\/em>, 136(15), 45678.<\/li>\n
- Brown, D., & Taylor, R. (2014). The influence of isocyanate type on the properties of polyurethane foams. Journal of Polymer Research<\/em>, 21(1), 1-12.<\/li>\n
- Yang, M., & Chen, X. (2017). Additives in polyurethane foams: Effects on catalytic activity and foam properties. Polymer Composites<\/em>, 38(10), 2567-2575.<\/li>\n<\/ol>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"
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