Determination and application of 1,3-Bis(aminomethyl)benzene

Introduction

1,3-Bis(aminomethyl)benzene (Figure 1),3-(aminomethyl)-benzylamine, m-xylylenediamine, and C8H12N2 (PM reference number 13000, CAS number 1477-55-0) are used in the synthesis of polyamides (for bags, barrier packs, etc.) and as hardeners for epoxy resin coatings intended for certain food containers (large metal or concrete vats or tanks for water, fruit juices, wine, oil, etc.). After manufacture, residual 1,3-bis(aminomethyl)benzene monomer can remain in the polymer and may migrate into foodstuffs coming into contact with the plastic material or article. [1]

1,3-Bis(aminomethyl)benzene determination in the official EU aqueous food simulants

The objective of this work was to develop a simple and rapid HPLC method for the quantitative determination of 1,3-bis(aminomethyl)benzene as its difluorescamine derivative in the three official EU aqueous food simulants: distilled water, 3% (w/v) acetic acid in water, and15% (v/v) ethanol in water.European Union directive 90/128/EEC prescribes a specific migration limit of 0.05 mg/kg for the aliphatic diamine 1,3-bis(aminomethyl)benzene into food or food simultants, but there is no generally accepted method of analysis available for compliance testing with the given restriction. A method is described for the determination of 1,3-bis(aminomethyl)benzene monomer in the following food simulants: distilled water, 3% (w/v) acetic acid, and 15% (v/v) ethanol. The method is appropriate for the quantitative determination of 1,3-bis(aminomethyl)benzene at a minimum level of 0.020 mg/kg in these food simulants. Detection limits are in the range of 0.004 to 0.010 mg 1,3-bis(aminomethyl)benzene per kilogram food simulant (depending on the type of food simulant). The method should also be applicable to other aqueous food simulants. 1,3-Bis(aminomethyl)benzene in aqueous simulant test samples is determined by high-performance liquid chromatography with fluorescence detection following derivatization with fluorescamine. Quantitation is relative to external standards. The identity of 1,3-bis(aminomethyl)benzene may be confirmed by the presence of a second peak in the chromatograms obtained from samples derivatized with less fluorescamine or by comparison with authentic samples.[1]

Synthesized MX and MXU resins 

Structural adhesion at high temperature has been a challenge for organic adhesives, and the commercially available adhesives that can work at a temperature above 150 °C is rather limited. Herein, two novel polymers were designed and synthesized via facile strategy, which involves polymerization between melamine (M) and 1,3-bis(aminomethyl)benzene (X), as well as copolymerization of MX and urea (U). With well-balanced rigid-flexible structures, the obtained MX and MXU resins were proved to be outstanding structural adhesives at a wide range temperature of -196~200 °C. They provided room-temperature bonding strength of 13~27 MPa for various substrates, steel bonding strength of 17~18 MPa at cryogenic temperature (-196 °C), and 15~17 MPa at 150 °C. Remarkably, high bonding strength of 10~11 MPa was retained even at 200 °C. Such superior performances were attributed to a high content of aromatic units, which leads to high glass transition temperature (Tg) up to ~179 °C, as well as the structural flexibility endowed by the dispersed rotatable methylene linkages.[2]

Synthesized thermo-Responsive Shape-Memory Dual-Cured Polymers

The development of thermo-responsive shape-memory polymers has attracted attention due to their ability to undergo reversible deformations based on temperature changes. Vegetable oils are confirmed to be an excellent biorenewable source of starting materials for the synthesis of polymers. Therefore, the objective of this research was to synthesize thermo-responsive shape-memory polymers based on vegetable oils by using the dual-curing technique and obtaining polymers with tailorable properties. Acrylated epoxidized soybean oil and two epoxidized vegetable oils, linseed oil and camelina oil, were chosen for dual curing with 1,3-bis(aminomethyl)benzene. Rheological tests were used to analyze the curing kinetics of systems undergoing radical photopolymerization, thermal cationic polymerization, and dual-curing processes. The rheological, mechanical, and thermal characteristics of the polymers were enhanced by the second curing stage. Dual-cured vegetable oil-based polymers had shape-memory properties with a recovery ratio of 100%, making them suitable for a variety of applications, including electronics, biomedical devices, and robotics.[3]

References

[1] Paseiro-Losada P, Simal-Gándara J, Sanmartin-Fenollera P, Pérez-Lamela C, López-Fabal F. m-Xylylenediamine determination in the official EU aqueous food simulants. J Chromatogr Sci. 1998;36(11):554-560. doi:10.1093/chromsci/36.11.554

[2] Niu H, Wang S, Shen Y, et al. Tough Structural Adhesives with Ultra-Resistance to Both High and Cryogenic Temperature. Polymers (Basel). 2023;15(10):2284. Published 2023 May 12. doi:10.3390/polym15102284

[3] Petrauskas R, Grauzeliene S, Ostrauskaite J. Thermo-Responsive Shape-Memory Dual-Cured Polymers Based on Vegetable Oils. Materials (Basel). 2023;17(1):24. Published 2023 Dec 20. doi:10.3390/ma17010024

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