Influence of uniaxial orientation of fluorinated polymer/phosphonate‐modified needle‐like nanofiller composite by drawing

Abstract

The orientation effect of sepiolite natural clay, a needle‐shaped nanoparticle, in a polymer matrix was investigated. Uniaxial drawing was performed on polymer‐based nanocomposites containing organo‐modified sepiolite, achieving uniform dispersion in the crystalline polymer by modifying the surface with organic molecular chains. Fluorinated polymer was used as the matrix, and sepiolite was modified using fluorinated chains. High‐temperature drawing was conducted to increase the density of amorphous chains in the fluoropolymer. Observations confirmed the orientation of the nanofiller in the drawing direction. When the filler content was intentionally increased, it was as if it were a nanosized mille‐feuille. As a result of 5× drawing, a 20% improvement in crystallinity was calculated. Small‐angle X‐ray scattering (SAXS) analysis showed a 32 Å increase in long‐period values. When high‐drawing was conducted, some amorphous parts transformed into crystals, and the difference in electron densities between the two regions widened, increasing the long‐period value while decreasing the SAXS intensity. The crystallization temperature increased by 1.8°C, and the Young's modulus calculated from the strain‐stress curve showed a nearly 4× increase. The mechanical strength doubled when the neat fluoropolymer was drawn five times. This provides a clear understanding of the enhancement behavior of the structural and physical properties of a uniform dispersible polymer/needle nanoparticle nanocomposite using uniaxially oriented nanofillers.

Infrared Linear Dichroism for the Analysis of Molecular Orientation in Polymers and in Polymer Composites

“…Other studies have used sepiolite fibers as filler in various polymeric matrices on account of their intrinsically anisotropic character and their orienting capability upon uniaxial drawing [ 69 , 70 , 71 , 72 ]. In the work of Hirayama et al [ 72 ] performed on polyvinylidene fluoride/fluorinated phosphonate-modified sepiolite composites, transmission electron microscopy imaging of uniaxially drawn films reveals a high degree of orientation of the needle-shaped nanoparticles along the stretching direction. The mechanical properties of the composites are seen to be significantly enhanced as a result of the uniaxial orientation of the dispersed nanofiller.…”

Curing, thermal, tensile and flammability characteristics of sepiolite/ethylene propylene diene monomer rubber composites with glut palmitate salt and silane coupling agents

“…[15,16] The potential of SEP as a filler was broadly studied in various polymer matrices. [17] They included natural rubber (NR), [18,19] fluorinated polymer [20] epoxidized natural rubber (ENR), [21] and nitrile butadiene rubber. [22] In general, the chemical nature of the matrix and nanofiller, as well as the degree of nanofiller dispersion, have a significant impact on the properties of the nanocomposites prepared.…”

Study on the improvement of dispersibility and orientation control of fluorocarbon‐modified single‐walled carbon nanotubes in a fluorinated polymer matrix

“…[25] On the other hand, there are cases where the fluorophilicity of the surfactant-modified molecular chain and the polymer is used in the preparation of polymer-based nanocomposites. [26,27] In the field of polymer physics, "nanocomposite" preparation technology that improves heat resistance and mechanical properties by dispersing a very small number of nanoparticles in a polymer is well known (Figure 1, upper part). [28][29][30] However, as mentioned above, there are generally few examples of improving the function of fluorinated crystalline polymers by compounding because of their phase separation characteristics.…”