Dispersion of nano-silica in monomer casting nylon6 and its effect on the structure and properties of composites

Abstract

Abstract.To promote dispersion of nano-silica in monomer casting nylon6 (MC nylon6), nano-silica was dispersed in melted caprolactam with the assistance of ultrasound, anionic polymerization was then initiated to form silica/MC nylon6 in-situ nanocomposites. It was found that hydrogen bonds were formed between nano-silica and caprolactam, in the meantime, ultrasound helped to break the nanoparticles aggregations into smaller ones or even mono-dispersing particles. Therefore, the agglomerated nanoparticles were pulled apart and stabilized by caprolactam. Additionally, the rapid anionic polymerization of caprolactam also contributed to the avoidance of re-agglomeration and deposition of nanoparticles during the polymerization process, leading to the uniform distribution of nanoparticles in the polymer matrix. Mechanical tests indicated that the silica/MC nylon6 in-situ nanocomposites prepared according to the above strategy were simultaneously toughened, strengthened and stiffened. Thermogravimetric analysis (TGA) results showed that thermal stability of nanocomposites was notably improved compared to neat MC nylon6.

Synthesis of Polyamide-6/Montmorillonite Nanocomposites by Direct In-situ Polymerization Catalysed by Exchanged Clay

“…According to Theng 32 and Velde 33 , the interaction between the amide groups of PA6 molecules and the ionic groups at the clay surfaces probably suppresses thermal degradation of the composite matrix. However, it is interesting to find that thermal stability of nanocomposites is slightly inferior to the virgin PA6 when higher weight loss (90%) is considered, the same results are obtained by Cai et al,34 . Such results indicate that the introduction of clay might change the decomposition mechanism of PA6 under high temperature.…”

In situ polymerization to prepare graphene-toughened monomer cast nylon composites

“…The results showed that the impact strength, tensile strength, and modulus of composites were doubled compared to pure MC nylon, while the thermal performance was also improved with 2 wt% of silica. He et al [4] prepared Y(OH) 3 /MC nylon composite, and it was found that with the incorporation of 0.25 wt% of Y(OH) 3 , the toughness of the composite increased by 60 %, and the water absorption reduced by 34 %, but the thermal stability barely changed. Huang et al [5] used the hydrotalcite as filler to prepare MC nylon composites.…”

“…It has been reported on utilizing nanomaterial to toughen MC nylon in various papers. Cai et al [3] added nanosilica into the melting caprolactam to prepare MC nylon nanocomposites by in situ polymerization. The results showed that the impact strength, tensile strength, and modulus of composites were doubled compared to pure MC nylon, while the thermal performance was also improved with 2 wt% of silica.…”

Polyamide 6/silica hybrid materials by a coupled polymerization reaction

“…by sol-gel processing 22 or the in situ polymerization of ε-caprolactam in presence of preformed silica particles. 15,[23][24][25][26] The grafting of PA6 on surface functionalized SiO 2 particles is also a suitable route to fabricate polymer/SiO 2 hybrid materials. 27,28 As an additional way, the simultaneous formation of both polymer components within one procedure is known.…”