Pyridine‐Modified Polymer as a Non‐Covalent Compatibilizer for Multi‐Walled CNT/Poly[ethylene‐co‐(methacrylic acid)] Composites Fabricated by Direct Melt Mixing

Abstract

Multi-wall CNT/poly[ethylene-co-(methacrylic acid)] composites were prepared by melt mixing. To improve dispersion and promote polymer/nanotube interactions, a novel non-covalent compatibilizer is synthesized by reacting the polymer with 4-(aminomethyl)pyridine. The composite based on the pristine polymer shows electrical and rheological percolation thresholds at nanotube loadings of 1.85 and 1.4 wt%, respectively. When 5 wt% of the pyridine-modified compatibilizer is added, the corresponding values are reduced to 1.44 and 0.8 wt%, respectively. The electrical resistivity decreases even further as 10 wt% of the novel dispersing agent is used. Microscopy and Raman spectroscopy confirm the improved dispersion and p-interactions established during melt mixing.

Pyridine modified polyethylene copolymer compatibilizer for melt blended carbon nanotube composites: effects of chain structure and matrix viscosity

“…The compatibilizer was synthesized similarly to a process reported elsewhere . Fifty grams of PEAA was dissolved in 500 ml of THF at 67°C for 12 h. A stoichiometric amount of AMP (3:1 molar ratio with respect to the acrylic acid content) were added, and the reaction was carried out for 12 h. The pyridine modified polymeric compatibilizer (PEAA‐AMP) was precipitated with cold methanol, filtered, washed extensively with methanol, and vacuum dried at 60°C.…”

“…In this work we continue to develop our previous concept, which is based on the pyridine modification of acidic copolymer as a route toward the synthesis of π‐interaction compatibilizer family for CNT composites. The advantage of such compatibilizer is that it does not change the CNT inherent structure and electrical properties from the one hand, but it is able to form strong non‐covalent interactions with the CNTs to increase chemical affinity.…”

Noncovalent compatibilization of polypropylene/MWCNT composites using an amino-pyridine grafted polypropylene matrix

“…The addition of the aromatic functionality to the PP backbone caused a more pronounced shift, providing evidence of increased polymer/filler interactions. This is likely attributable to the noncovalent p-p interaction between pyridine groups and nanotube sidewalls [3,27]. Figure 8 shows that addition of 1.7 vol% MWCNTs resulted in an increase in composite conductivity by approximately 13 orders of magnitude.…”

“…Fitting of this model to the data shown in Fig. 8 resulted in a percolation threshold value of u c 50.7 vol% (1.2 wt% estimated using a MWCNT density of 1.65 g/ cm 3 ) for both PP/PP-g-MA and PP/PP-g-Py matrices. These values are lower than the percolation thresholds reported in the literature for PP.…”

“…MWCNTs were first premixed with the PP in a Carver hot press at 200 C for 1 min, by folding and hot-pressing three times. The resulting mixtures were subsequently added in the microcompounder, together with Irganox B225, to produce composites containing 0.5 to 5 wt% (0.3 to 2.8 vol% converted assuming densities of 0.9 and 1.65 g/cm 3 for PP and MWCNTs, respectively). Neat PP was subjected to a similar processing history, to provide a basis for comparison.…”