Preparation of a Latent Accelerator for Hot Curing of Epoxy Resin and Study of Its Effect on Mechanical Properties of Carbon Fiber Epoxy Composites

Document Type : Research Paper

Authors

1 Science and Research Branch, Islamic Azad University, Postal Code 1477893855, Tehran, Iran

2 Department of Composite, Faculty of Polymer Processing, Iran Polymer and Petrochemical Institute, P.O. Box 14975-112, Tehran, Iran

Abstract

Hypothesis: Some adducts were prepared from three kinds of DGEBA-based epoxy resins, phthalic anhydride and an alkanol amine accelerator, as a latent accelerator for one-pot epoxy/dicy systems. These adducts come with two kinds of accelerators: DMP-30 A, which is lab-grade and Ax-10, which is industrial-grade, as well as DGEBA based epoxy resins Epikote 828, Epiran 06 and ML 504. The adduct made of Epikote 828 and DMP-30 A was considered as a reference. It seems that it might be possible to prepare a new efficient latent accelerator with change of epoxy resin and accelerator.
Methods: For this purpose, four different adducts with resins and accelerators and four different epoxy/dicy mixtures with four adduct types and AX-10 accelerator and one with no adduct as a reference were prepared. Measuring the melting point, viscosity build-up versus time, gelation time, non-isothermal differential scanning calorimetry (DSC) and glass transition temperature characterization and also lap shear, interlaminar shear strength, transvers tensile and scanning electron microscope (SEM) were used to study the latent properties of the prepared adducts in the epoxy/dicy system and find its effect on mechanical properties of the final composites and all were compared with references.
Findings: Melting point of all adducts is above room temperature, so they are solid at room temperature. The results show that the adducts containing the industrial accelerator in one-pot epoxy/dicy system has lower gel time at high temperature, higher viscosity changes at ambient temperature and pot life and has made no significant change in cure temperature. The mechanical properties of the composite made with an adduct consisting of ML 504 resin are accompanied by a decrease in the related values. In general, the adduct made with Epiran 06 or Epikote 828 resin and industrial accelerator is an efficient and new latent accelerator and is suitable for preparing one-pot epoxy/dicy systems.

Keywords


  1. Ke L., Li C., He J., Dong S., Chen C., and Jiao Y., Effects of Elevated Temperatures on Mechanical Behavior of Epoxy Adhesives and CFRP-Steel Hybrid Joints, Compos. Struct., 235, 111789-11798, 2020.
  2. Mozaffari S.M. and Beheshty M.H., Thermally-Latent Curing Agents for Epoxy Resins: A Review, J. Polym. Scie. Technol. (Persian), 31, 409-426, 2018.
  3. Yang B., Mao Y., Zhang Y., Guofeng B., Zhang L., Wei Y., and Liu W., A Novel Liquid Imidazole-Copper (II) Complex as a Thermal Latent Curing Agent for Epoxy Resins, Polymer, 178, 121586, 2019.
  4. Varganici C.D., Rosu L., Rosu D., Hamciuc C., Rosca I., and Vasiliu A.L., Effect of Hardener Type on the Photochemical and Antifungal Performance of Epoxy and Oligophosphonate S–IPNs, Polymers, 14, 3784-3805, 2022.
  5. Shi K., Shen Y., Yang Y., and Wang T., Novel Imidazole Derivatives with Recoverable Activity as Latent Curing Agents for Epoxy, Appl. Polym. Sci., 138, 49730, 2021.
  6. Gaukler J.C., Müller U., Krüger J.K., and Possart W., Functional Nano Fillers in Epoxy-Dicyandiamide Adhesives for Prolonged Shelf Life and Efficient Cure, e-Polymers, 11, 2011.
  7. Mozaffari S.M. and Beheshty M.H., and Nanoclay-Modified Microcapsules as a Latent Curing Agent in Epoxy, Bull., 78, 3103-3115. 2021.
  8. Reuther P., Dünnwald P., Tabatabai M., Schuh C., Hartmann L., and Ritter H., Thermally Controlled Acceleration of Epoxy Resin Curing through Polymer-Bound Imidazole Derivatives with High Latency,ACS Appl. Polym. Mater., 4, 1150-1158, 2022.
  9. Hamerton I., Howlin B.J., and Jepson P., Metals and Coordination Compounds as Modifiers for Epoxy Resins, Chem. Rev., 224, 67-85, 2002.
  10. Barton J.M., Buist G.J., Hamerton L., Howlin B.J., Jones J.R., and Liu S., Preparation and Characterization of Imidazole-Metal Complexes and Evaluation of Cured Epoxy Networks, Mater. Chem., 4, 379-384, 1994.
  11. Lin R.H., Chen C.L., Kao L.H., and Yang P.R., Cure Behavior of Epoxy Resins with Different Kinds of Onium Salts as Latent Thermal Catalysts, Appl. Polym. Sci., 82, 3539-3551, 2001.
  12. Smith J.D.B., Quaternary Phosphonium Compound Latent Accelerators for Anhydride-Cured Epoxy Resins, Appl. Polym. Sci., 23, 47-56, 2009.
  13. Xing S., Yang J., Huang Y., Zheng Q., and Zeng J., Preparation and Characterization of a Novel Microcapsule-Type Latent Curing Agent for Epoxy Resin, Design, 85, 661-670, 2015.
  14. Xu Y., Wang J., Tan Y., Qi M., Chen L., and Wang Y., A Novel and Feasible Approach for One-Pack Flame-Retardant Epoxy Resin with Long Pot Life and Fast Curing, Eng. J., 337, 30-39, 2018.
  15. Liu X.D., Kimura M., Sudo A., and Endo T., Accelerating Effects of N-Aryl-N′,N′-Dialkyl Ureas on Epoxy-Dicyandiamide Curing System, Polym. Sci., Part A: Polym. Chem., 48, 5298-5305, 2010.
  16. Liu X.D., Zhao C.H., Sudo A., and Endo T., Storage Stability and Curing Behavior of Epoxy-Dicyandiamide Systems with Carbonyldiimidazole-Cu (II) Complexes as the Accelerator, Polym. Sci., Part A: Polym. Chem., 51, 3470-3476, 2013.
  17. Hesabi M., Salimi A., and Beheshty M.H., Development of Amine-Based Latent Accelerator for One-Pot Epoxy System with Low Curing Temperature and High Shelf Life, Polym. J., 112, 736-748, 2019
  18. Niazi M. and Beheshty M.H., A New Latent Accelerator and Study of Its Effect on Physical, Mechanical and Shelf-Life of Carbon Fiber Epoxy Prepreg, Polym. J., 28, 337-346, 2019.
  19. Saadatyar S., Beheshty M.H., and Sahraeian R., Mechanical Properties of Multiwall Carbon Nanotubes/Unidirectional Carbon Fiber-Reinforced Epoxy Hybrid Nanocomposites in Transverse and Longitudinal Fiber Directions, Polym. Compos., 29, S74-S84, 2021.
  20. Kamalipour J., Beheshty M.H., and Zohurianmehr J., Novel Phosphonated Hardeners Derived from Diamino Diphenyl Sulfone for Epoxy Resins: Synthesis and One-Pack Flame-Retardant Formulation Alongside Dicyandiamide, Degrad. Stab., 199, 109917-109935, 2022.
  21. Dareh M., Beheshty M.H., and Bazgir S., Effect of Type and Amount of Accelerator on Reactivity and Curing Behavior of Epoxy/Dicyandiamide/Accelerator System, J. Polym. Sci. Technol. (Persian), 33, 329–338, 2020.
  22. Yang S., Zhang Q., Hu Y., Ding G., and Wang J., Synthesis of Maleimide Modified Imidazole Derivatives and Their Application in One-Component Epoxy Resin Systems, Lett., 234, 379-383, 2019.
  23. Guzmán D., Ramis X., Fernández-Francos X., and Serra A., New Catalysts for Diglycidyl Ether of Bisphenol A Curing Based on Thiol–Epoxy Click Reaction, Polym. J., 59, 377-386, 2014.
  24. Baek D., Sim K.B., and Kim H.J., Mechanical Characterization of Core-Shell Rubber/Epoxy Polymers for Automotive Structural Adhesives as a Function of Operating Temperature, Polymers, 13, 734, 2021.
  25. Xiao S., Bi. M., Huang L., Rong H., Jia L., Ran J., Low Viscosity and High Strength Room Temperature Cured Epoxy Structural Adhesive Based on Different Amine Curing Agents, Available at SSRN,18 February 2022. DOI: http://dx.doi.org/10.2139/ssrn.4135042